The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_descrip.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1989, 1991, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  * (c) UNIX System Laboratories, Inc.
    5  * All or some portions of this file are derived from material licensed
    6  * to the University of California by American Telephone and Telegraph
    7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
    8  * the permission of UNIX System Laboratories, Inc.
    9  *
   10  * Redistribution and use in source and binary forms, with or without
   11  * modification, are permitted provided that the following conditions
   12  * are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above copyright
   16  *    notice, this list of conditions and the following disclaimer in the
   17  *    documentation and/or other materials provided with the distribution.
   18  * 4. Neither the name of the University nor the names of its contributors
   19  *    may be used to endorse or promote products derived from this software
   20  *    without specific prior written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   32  * SUCH DAMAGE.
   33  *
   34  *      @(#)kern_descrip.c      8.6 (Berkeley) 4/19/94
   35  */
   36 
   37 #include <sys/cdefs.h>
   38 __FBSDID("$FreeBSD: releng/8.1/sys/kern/kern_descrip.c 207513 2010-05-02 15:58:25Z bz $");
   39 
   40 #include "opt_compat.h"
   41 #include "opt_ddb.h"
   42 #include "opt_ktrace.h"
   43 
   44 #include <sys/param.h>
   45 #include <sys/systm.h>
   46 
   47 #include <sys/conf.h>
   48 #include <sys/domain.h>
   49 #include <sys/fcntl.h>
   50 #include <sys/file.h>
   51 #include <sys/filedesc.h>
   52 #include <sys/filio.h>
   53 #include <sys/jail.h>
   54 #include <sys/kernel.h>
   55 #include <sys/limits.h>
   56 #include <sys/lock.h>
   57 #include <sys/malloc.h>
   58 #include <sys/mount.h>
   59 #include <sys/mqueue.h>
   60 #include <sys/mutex.h>
   61 #include <sys/namei.h>
   62 #include <sys/priv.h>
   63 #include <sys/proc.h>
   64 #include <sys/protosw.h>
   65 #include <sys/resourcevar.h>
   66 #include <sys/signalvar.h>
   67 #include <sys/socketvar.h>
   68 #include <sys/stat.h>
   69 #include <sys/sx.h>
   70 #include <sys/syscallsubr.h>
   71 #include <sys/sysctl.h>
   72 #include <sys/sysproto.h>
   73 #include <sys/tty.h>
   74 #include <sys/unistd.h>
   75 #include <sys/user.h>
   76 #include <sys/vnode.h>
   77 #ifdef KTRACE
   78 #include <sys/ktrace.h>
   79 #endif
   80 
   81 #include <security/audit/audit.h>
   82 
   83 #include <vm/uma.h>
   84 
   85 #include <ddb/ddb.h>
   86 
   87 static MALLOC_DEFINE(M_FILEDESC, "filedesc", "Open file descriptor table");
   88 static MALLOC_DEFINE(M_FILEDESC_TO_LEADER, "filedesc_to_leader",
   89                      "file desc to leader structures");
   90 static MALLOC_DEFINE(M_SIGIO, "sigio", "sigio structures");
   91 
   92 static uma_zone_t file_zone;
   93 
   94 
   95 /* Flags for do_dup() */
   96 #define DUP_FIXED       0x1     /* Force fixed allocation */
   97 #define DUP_FCNTL       0x2     /* fcntl()-style errors */
   98 
   99 static int do_dup(struct thread *td, int flags, int old, int new,
  100     register_t *retval);
  101 static int      fd_first_free(struct filedesc *, int, int);
  102 static int      fd_last_used(struct filedesc *, int, int);
  103 static void     fdgrowtable(struct filedesc *, int);
  104 static void     fdunused(struct filedesc *fdp, int fd);
  105 static void     fdused(struct filedesc *fdp, int fd);
  106 
  107 /*
  108  * A process is initially started out with NDFILE descriptors stored within
  109  * this structure, selected to be enough for typical applications based on
  110  * the historical limit of 20 open files (and the usage of descriptors by
  111  * shells).  If these descriptors are exhausted, a larger descriptor table
  112  * may be allocated, up to a process' resource limit; the internal arrays
  113  * are then unused.
  114  */
  115 #define NDFILE          20
  116 #define NDSLOTSIZE      sizeof(NDSLOTTYPE)
  117 #define NDENTRIES       (NDSLOTSIZE * __CHAR_BIT)
  118 #define NDSLOT(x)       ((x) / NDENTRIES)
  119 #define NDBIT(x)        ((NDSLOTTYPE)1 << ((x) % NDENTRIES))
  120 #define NDSLOTS(x)      (((x) + NDENTRIES - 1) / NDENTRIES)
  121 
  122 /*
  123  * Storage required per open file descriptor.
  124  */
  125 #define OFILESIZE (sizeof(struct file *) + sizeof(char))
  126 
  127 /*
  128  * Storage to hold unused ofiles that need to be reclaimed.
  129  */
  130 struct freetable {
  131         struct file     **ft_table;
  132         SLIST_ENTRY(freetable) ft_next;
  133 };
  134 
  135 /*
  136  * Basic allocation of descriptors:
  137  * one of the above, plus arrays for NDFILE descriptors.
  138  */
  139 struct filedesc0 {
  140         struct  filedesc fd_fd;
  141         /*
  142          * ofiles which need to be reclaimed on free.
  143          */
  144         SLIST_HEAD(,freetable) fd_free;
  145         /*
  146          * These arrays are used when the number of open files is
  147          * <= NDFILE, and are then pointed to by the pointers above.
  148          */
  149         struct  file *fd_dfiles[NDFILE];
  150         char    fd_dfileflags[NDFILE];
  151         NDSLOTTYPE fd_dmap[NDSLOTS(NDFILE)];
  152 };
  153 
  154 /*
  155  * Descriptor management.
  156  */
  157 volatile int openfiles;                 /* actual number of open files */
  158 struct mtx sigio_lock;          /* mtx to protect pointers to sigio */
  159 void    (*mq_fdclose)(struct thread *td, int fd, struct file *fp);
  160 
  161 /* A mutex to protect the association between a proc and filedesc. */
  162 static struct mtx       fdesc_mtx;
  163 
  164 /*
  165  * Find the first zero bit in the given bitmap, starting at low and not
  166  * exceeding size - 1.
  167  */
  168 static int
  169 fd_first_free(struct filedesc *fdp, int low, int size)
  170 {
  171         NDSLOTTYPE *map = fdp->fd_map;
  172         NDSLOTTYPE mask;
  173         int off, maxoff;
  174 
  175         if (low >= size)
  176                 return (low);
  177 
  178         off = NDSLOT(low);
  179         if (low % NDENTRIES) {
  180                 mask = ~(~(NDSLOTTYPE)0 >> (NDENTRIES - (low % NDENTRIES)));
  181                 if ((mask &= ~map[off]) != 0UL)
  182                         return (off * NDENTRIES + ffsl(mask) - 1);
  183                 ++off;
  184         }
  185         for (maxoff = NDSLOTS(size); off < maxoff; ++off)
  186                 if (map[off] != ~0UL)
  187                         return (off * NDENTRIES + ffsl(~map[off]) - 1);
  188         return (size);
  189 }
  190 
  191 /*
  192  * Find the highest non-zero bit in the given bitmap, starting at low and
  193  * not exceeding size - 1.
  194  */
  195 static int
  196 fd_last_used(struct filedesc *fdp, int low, int size)
  197 {
  198         NDSLOTTYPE *map = fdp->fd_map;
  199         NDSLOTTYPE mask;
  200         int off, minoff;
  201 
  202         if (low >= size)
  203                 return (-1);
  204 
  205         off = NDSLOT(size);
  206         if (size % NDENTRIES) {
  207                 mask = ~(~(NDSLOTTYPE)0 << (size % NDENTRIES));
  208                 if ((mask &= map[off]) != 0)
  209                         return (off * NDENTRIES + flsl(mask) - 1);
  210                 --off;
  211         }
  212         for (minoff = NDSLOT(low); off >= minoff; --off)
  213                 if (map[off] != 0)
  214                         return (off * NDENTRIES + flsl(map[off]) - 1);
  215         return (low - 1);
  216 }
  217 
  218 static int
  219 fdisused(struct filedesc *fdp, int fd)
  220 {
  221         KASSERT(fd >= 0 && fd < fdp->fd_nfiles,
  222             ("file descriptor %d out of range (0, %d)", fd, fdp->fd_nfiles));
  223         return ((fdp->fd_map[NDSLOT(fd)] & NDBIT(fd)) != 0);
  224 }
  225 
  226 /*
  227  * Mark a file descriptor as used.
  228  */
  229 static void
  230 fdused(struct filedesc *fdp, int fd)
  231 {
  232 
  233         FILEDESC_XLOCK_ASSERT(fdp);
  234         KASSERT(!fdisused(fdp, fd),
  235             ("fd already used"));
  236 
  237         fdp->fd_map[NDSLOT(fd)] |= NDBIT(fd);
  238         if (fd > fdp->fd_lastfile)
  239                 fdp->fd_lastfile = fd;
  240         if (fd == fdp->fd_freefile)
  241                 fdp->fd_freefile = fd_first_free(fdp, fd, fdp->fd_nfiles);
  242 }
  243 
  244 /*
  245  * Mark a file descriptor as unused.
  246  */
  247 static void
  248 fdunused(struct filedesc *fdp, int fd)
  249 {
  250 
  251         FILEDESC_XLOCK_ASSERT(fdp);
  252         KASSERT(fdisused(fdp, fd),
  253             ("fd is already unused"));
  254         KASSERT(fdp->fd_ofiles[fd] == NULL,
  255             ("fd is still in use"));
  256 
  257         fdp->fd_map[NDSLOT(fd)] &= ~NDBIT(fd);
  258         if (fd < fdp->fd_freefile)
  259                 fdp->fd_freefile = fd;
  260         if (fd == fdp->fd_lastfile)
  261                 fdp->fd_lastfile = fd_last_used(fdp, 0, fd);
  262 }
  263 
  264 /*
  265  * System calls on descriptors.
  266  */
  267 #ifndef _SYS_SYSPROTO_H_
  268 struct getdtablesize_args {
  269         int     dummy;
  270 };
  271 #endif
  272 /* ARGSUSED */
  273 int
  274 getdtablesize(struct thread *td, struct getdtablesize_args *uap)
  275 {
  276         struct proc *p = td->td_proc;
  277 
  278         PROC_LOCK(p);
  279         td->td_retval[0] =
  280             min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
  281         PROC_UNLOCK(p);
  282         return (0);
  283 }
  284 
  285 /*
  286  * Duplicate a file descriptor to a particular value.
  287  *
  288  * Note: keep in mind that a potential race condition exists when closing
  289  * descriptors from a shared descriptor table (via rfork).
  290  */
  291 #ifndef _SYS_SYSPROTO_H_
  292 struct dup2_args {
  293         u_int   from;
  294         u_int   to;
  295 };
  296 #endif
  297 /* ARGSUSED */
  298 int
  299 dup2(struct thread *td, struct dup2_args *uap)
  300 {
  301 
  302         return (do_dup(td, DUP_FIXED, (int)uap->from, (int)uap->to,
  303                     td->td_retval));
  304 }
  305 
  306 /*
  307  * Duplicate a file descriptor.
  308  */
  309 #ifndef _SYS_SYSPROTO_H_
  310 struct dup_args {
  311         u_int   fd;
  312 };
  313 #endif
  314 /* ARGSUSED */
  315 int
  316 dup(struct thread *td, struct dup_args *uap)
  317 {
  318 
  319         return (do_dup(td, 0, (int)uap->fd, 0, td->td_retval));
  320 }
  321 
  322 /*
  323  * The file control system call.
  324  */
  325 #ifndef _SYS_SYSPROTO_H_
  326 struct fcntl_args {
  327         int     fd;
  328         int     cmd;
  329         long    arg;
  330 };
  331 #endif
  332 /* ARGSUSED */
  333 int
  334 fcntl(struct thread *td, struct fcntl_args *uap)
  335 {
  336         struct flock fl;
  337         struct oflock ofl;
  338         intptr_t arg;
  339         int error;
  340         int cmd;
  341 
  342         error = 0;
  343         cmd = uap->cmd;
  344         switch (uap->cmd) {
  345         case F_OGETLK:
  346         case F_OSETLK:
  347         case F_OSETLKW:
  348                 /*
  349                  * Convert old flock structure to new.
  350                  */
  351                 error = copyin((void *)(intptr_t)uap->arg, &ofl, sizeof(ofl));
  352                 fl.l_start = ofl.l_start;
  353                 fl.l_len = ofl.l_len;
  354                 fl.l_pid = ofl.l_pid;
  355                 fl.l_type = ofl.l_type;
  356                 fl.l_whence = ofl.l_whence;
  357                 fl.l_sysid = 0;
  358 
  359                 switch (uap->cmd) {
  360                 case F_OGETLK:
  361                     cmd = F_GETLK;
  362                     break;
  363                 case F_OSETLK:
  364                     cmd = F_SETLK;
  365                     break;
  366                 case F_OSETLKW:
  367                     cmd = F_SETLKW;
  368                     break;
  369                 }
  370                 arg = (intptr_t)&fl;
  371                 break;
  372         case F_GETLK:
  373         case F_SETLK:
  374         case F_SETLKW:
  375         case F_SETLK_REMOTE:
  376                 error = copyin((void *)(intptr_t)uap->arg, &fl, sizeof(fl));
  377                 arg = (intptr_t)&fl;
  378                 break;
  379         default:
  380                 arg = uap->arg;
  381                 break;
  382         }
  383         if (error)
  384                 return (error);
  385         error = kern_fcntl(td, uap->fd, cmd, arg);
  386         if (error)
  387                 return (error);
  388         if (uap->cmd == F_OGETLK) {
  389                 ofl.l_start = fl.l_start;
  390                 ofl.l_len = fl.l_len;
  391                 ofl.l_pid = fl.l_pid;
  392                 ofl.l_type = fl.l_type;
  393                 ofl.l_whence = fl.l_whence;
  394                 error = copyout(&ofl, (void *)(intptr_t)uap->arg, sizeof(ofl));
  395         } else if (uap->cmd == F_GETLK) {
  396                 error = copyout(&fl, (void *)(intptr_t)uap->arg, sizeof(fl));
  397         }
  398         return (error);
  399 }
  400 
  401 static inline struct file *
  402 fdtofp(int fd, struct filedesc *fdp)
  403 {
  404         struct file *fp;
  405 
  406         FILEDESC_LOCK_ASSERT(fdp);
  407         if ((unsigned)fd >= fdp->fd_nfiles ||
  408             (fp = fdp->fd_ofiles[fd]) == NULL)
  409                 return (NULL);
  410         return (fp);
  411 }
  412 
  413 int
  414 kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg)
  415 {
  416         struct filedesc *fdp;
  417         struct flock *flp;
  418         struct file *fp;
  419         struct proc *p;
  420         char *pop;
  421         struct vnode *vp;
  422         int error, flg, tmp;
  423         int vfslocked;
  424         u_int old, new;
  425         uint64_t bsize;
  426 
  427         vfslocked = 0;
  428         error = 0;
  429         flg = F_POSIX;
  430         p = td->td_proc;
  431         fdp = p->p_fd;
  432 
  433         switch (cmd) {
  434         case F_DUPFD:
  435                 tmp = arg;
  436                 error = do_dup(td, DUP_FCNTL, fd, tmp, td->td_retval);
  437                 break;
  438 
  439         case F_DUP2FD:
  440                 tmp = arg;
  441                 error = do_dup(td, DUP_FIXED, fd, tmp, td->td_retval);
  442                 break;
  443 
  444         case F_GETFD:
  445                 FILEDESC_SLOCK(fdp);
  446                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  447                         FILEDESC_SUNLOCK(fdp);
  448                         error = EBADF;
  449                         break;
  450                 }
  451                 pop = &fdp->fd_ofileflags[fd];
  452                 td->td_retval[0] = (*pop & UF_EXCLOSE) ? FD_CLOEXEC : 0;
  453                 FILEDESC_SUNLOCK(fdp);
  454                 break;
  455 
  456         case F_SETFD:
  457                 FILEDESC_XLOCK(fdp);
  458                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  459                         FILEDESC_XUNLOCK(fdp);
  460                         error = EBADF;
  461                         break;
  462                 }
  463                 pop = &fdp->fd_ofileflags[fd];
  464                 *pop = (*pop &~ UF_EXCLOSE) |
  465                     (arg & FD_CLOEXEC ? UF_EXCLOSE : 0);
  466                 FILEDESC_XUNLOCK(fdp);
  467                 break;
  468 
  469         case F_GETFL:
  470                 FILEDESC_SLOCK(fdp);
  471                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  472                         FILEDESC_SUNLOCK(fdp);
  473                         error = EBADF;
  474                         break;
  475                 }
  476                 td->td_retval[0] = OFLAGS(fp->f_flag);
  477                 FILEDESC_SUNLOCK(fdp);
  478                 break;
  479 
  480         case F_SETFL:
  481                 FILEDESC_SLOCK(fdp);
  482                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  483                         FILEDESC_SUNLOCK(fdp);
  484                         error = EBADF;
  485                         break;
  486                 }
  487                 fhold(fp);
  488                 FILEDESC_SUNLOCK(fdp);
  489                 do {
  490                         tmp = flg = fp->f_flag;
  491                         tmp &= ~FCNTLFLAGS;
  492                         tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS;
  493                 } while(atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0);
  494                 tmp = fp->f_flag & FNONBLOCK;
  495                 error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
  496                 if (error) {
  497                         fdrop(fp, td);
  498                         break;
  499                 }
  500                 tmp = fp->f_flag & FASYNC;
  501                 error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td);
  502                 if (error == 0) {
  503                         fdrop(fp, td);
  504                         break;
  505                 }
  506                 atomic_clear_int(&fp->f_flag, FNONBLOCK);
  507                 tmp = 0;
  508                 (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td);
  509                 fdrop(fp, td);
  510                 break;
  511 
  512         case F_GETOWN:
  513                 FILEDESC_SLOCK(fdp);
  514                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  515                         FILEDESC_SUNLOCK(fdp);
  516                         error = EBADF;
  517                         break;
  518                 }
  519                 fhold(fp);
  520                 FILEDESC_SUNLOCK(fdp);
  521                 error = fo_ioctl(fp, FIOGETOWN, &tmp, td->td_ucred, td);
  522                 if (error == 0)
  523                         td->td_retval[0] = tmp;
  524                 fdrop(fp, td);
  525                 break;
  526 
  527         case F_SETOWN:
  528                 FILEDESC_SLOCK(fdp);
  529                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  530                         FILEDESC_SUNLOCK(fdp);
  531                         error = EBADF;
  532                         break;
  533                 }
  534                 fhold(fp);
  535                 FILEDESC_SUNLOCK(fdp);
  536                 tmp = arg;
  537                 error = fo_ioctl(fp, FIOSETOWN, &tmp, td->td_ucred, td);
  538                 fdrop(fp, td);
  539                 break;
  540 
  541         case F_SETLK_REMOTE:
  542                 error = priv_check(td, PRIV_NFS_LOCKD);
  543                 if (error)
  544                         return (error);
  545                 flg = F_REMOTE;
  546                 goto do_setlk;
  547 
  548         case F_SETLKW:
  549                 flg |= F_WAIT;
  550                 /* FALLTHROUGH F_SETLK */
  551 
  552         case F_SETLK:
  553         do_setlk:
  554                 FILEDESC_SLOCK(fdp);
  555                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  556                         FILEDESC_SUNLOCK(fdp);
  557                         error = EBADF;
  558                         break;
  559                 }
  560                 if (fp->f_type != DTYPE_VNODE) {
  561                         FILEDESC_SUNLOCK(fdp);
  562                         error = EBADF;
  563                         break;
  564                 }
  565                 flp = (struct flock *)arg;
  566                 if (flp->l_whence == SEEK_CUR) {
  567                         if (fp->f_offset < 0 ||
  568                             (flp->l_start > 0 &&
  569                              fp->f_offset > OFF_MAX - flp->l_start)) {
  570                                 FILEDESC_SUNLOCK(fdp);
  571                                 error = EOVERFLOW;
  572                                 break;
  573                         }
  574                         flp->l_start += fp->f_offset;
  575                 }
  576 
  577                 /*
  578                  * VOP_ADVLOCK() may block.
  579                  */
  580                 fhold(fp);
  581                 FILEDESC_SUNLOCK(fdp);
  582                 vp = fp->f_vnode;
  583                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  584                 switch (flp->l_type) {
  585                 case F_RDLCK:
  586                         if ((fp->f_flag & FREAD) == 0) {
  587                                 error = EBADF;
  588                                 break;
  589                         }
  590                         PROC_LOCK(p->p_leader);
  591                         p->p_leader->p_flag |= P_ADVLOCK;
  592                         PROC_UNLOCK(p->p_leader);
  593                         error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
  594                             flp, flg);
  595                         break;
  596                 case F_WRLCK:
  597                         if ((fp->f_flag & FWRITE) == 0) {
  598                                 error = EBADF;
  599                                 break;
  600                         }
  601                         PROC_LOCK(p->p_leader);
  602                         p->p_leader->p_flag |= P_ADVLOCK;
  603                         PROC_UNLOCK(p->p_leader);
  604                         error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_SETLK,
  605                             flp, flg);
  606                         break;
  607                 case F_UNLCK:
  608                         error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_UNLCK,
  609                             flp, flg);
  610                         break;
  611                 case F_UNLCKSYS:
  612                         /*
  613                          * Temporary api for testing remote lock
  614                          * infrastructure.
  615                          */
  616                         if (flg != F_REMOTE) {
  617                                 error = EINVAL;
  618                                 break;
  619                         }
  620                         error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
  621                             F_UNLCKSYS, flp, flg);
  622                         break;
  623                 default:
  624                         error = EINVAL;
  625                         break;
  626                 }
  627                 VFS_UNLOCK_GIANT(vfslocked);
  628                 vfslocked = 0;
  629                 /* Check for race with close */
  630                 FILEDESC_SLOCK(fdp);
  631                 if ((unsigned) fd >= fdp->fd_nfiles ||
  632                     fp != fdp->fd_ofiles[fd]) {
  633                         FILEDESC_SUNLOCK(fdp);
  634                         flp->l_whence = SEEK_SET;
  635                         flp->l_start = 0;
  636                         flp->l_len = 0;
  637                         flp->l_type = F_UNLCK;
  638                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  639                         (void) VOP_ADVLOCK(vp, (caddr_t)p->p_leader,
  640                                            F_UNLCK, flp, F_POSIX);
  641                         VFS_UNLOCK_GIANT(vfslocked);
  642                         vfslocked = 0;
  643                 } else
  644                         FILEDESC_SUNLOCK(fdp);
  645                 fdrop(fp, td);
  646                 break;
  647 
  648         case F_GETLK:
  649                 FILEDESC_SLOCK(fdp);
  650                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  651                         FILEDESC_SUNLOCK(fdp);
  652                         error = EBADF;
  653                         break;
  654                 }
  655                 if (fp->f_type != DTYPE_VNODE) {
  656                         FILEDESC_SUNLOCK(fdp);
  657                         error = EBADF;
  658                         break;
  659                 }
  660                 flp = (struct flock *)arg;
  661                 if (flp->l_type != F_RDLCK && flp->l_type != F_WRLCK &&
  662                     flp->l_type != F_UNLCK) {
  663                         FILEDESC_SUNLOCK(fdp);
  664                         error = EINVAL;
  665                         break;
  666                 }
  667                 if (flp->l_whence == SEEK_CUR) {
  668                         if ((flp->l_start > 0 &&
  669                             fp->f_offset > OFF_MAX - flp->l_start) ||
  670                             (flp->l_start < 0 &&
  671                              fp->f_offset < OFF_MIN - flp->l_start)) {
  672                                 FILEDESC_SUNLOCK(fdp);
  673                                 error = EOVERFLOW;
  674                                 break;
  675                         }
  676                         flp->l_start += fp->f_offset;
  677                 }
  678                 /*
  679                  * VOP_ADVLOCK() may block.
  680                  */
  681                 fhold(fp);
  682                 FILEDESC_SUNLOCK(fdp);
  683                 vp = fp->f_vnode;
  684                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  685                 error = VOP_ADVLOCK(vp, (caddr_t)p->p_leader, F_GETLK, flp,
  686                     F_POSIX);
  687                 VFS_UNLOCK_GIANT(vfslocked);
  688                 vfslocked = 0;
  689                 fdrop(fp, td);
  690                 break;
  691 
  692         case F_RDAHEAD:
  693                 arg = arg ? 128 * 1024: 0;
  694                 /* FALLTHROUGH */
  695         case F_READAHEAD:
  696                 FILEDESC_SLOCK(fdp);
  697                 if ((fp = fdtofp(fd, fdp)) == NULL) {
  698                         FILEDESC_SUNLOCK(fdp);
  699                         error = EBADF;
  700                         break;
  701                 }
  702                 if (fp->f_type != DTYPE_VNODE) {
  703                         FILEDESC_SUNLOCK(fdp);
  704                         error = EBADF;
  705                         break;
  706                 }
  707                 fhold(fp);
  708                 FILEDESC_SUNLOCK(fdp);
  709                 if (arg != 0) {
  710                         vp = fp->f_vnode;
  711                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
  712                         error = vn_lock(vp, LK_SHARED);
  713                         if (error != 0)
  714                                 goto readahead_vnlock_fail;
  715                         bsize = fp->f_vnode->v_mount->mnt_stat.f_iosize;
  716                         VOP_UNLOCK(vp, 0);
  717                         fp->f_seqcount = (arg + bsize - 1) / bsize;
  718                         do {
  719                                 new = old = fp->f_flag;
  720                                 new |= FRDAHEAD;
  721                         } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new));
  722 readahead_vnlock_fail:
  723                         VFS_UNLOCK_GIANT(vfslocked);
  724                         vfslocked = 0;
  725                 } else {
  726                         do {
  727                                 new = old = fp->f_flag;
  728                                 new &= ~FRDAHEAD;
  729                         } while (!atomic_cmpset_rel_int(&fp->f_flag, old, new));
  730                 }
  731                 fdrop(fp, td);
  732                 break;
  733 
  734         default:
  735                 error = EINVAL;
  736                 break;
  737         }
  738         VFS_UNLOCK_GIANT(vfslocked);
  739         return (error);
  740 }
  741 
  742 /*
  743  * Common code for dup, dup2, fcntl(F_DUPFD) and fcntl(F_DUP2FD).
  744  */
  745 static int
  746 do_dup(struct thread *td, int flags, int old, int new,
  747     register_t *retval)
  748 {
  749         struct filedesc *fdp;
  750         struct proc *p;
  751         struct file *fp;
  752         struct file *delfp;
  753         int error, holdleaders, maxfd;
  754 
  755         p = td->td_proc;
  756         fdp = p->p_fd;
  757 
  758         /*
  759          * Verify we have a valid descriptor to dup from and possibly to
  760          * dup to. Unlike dup() and dup2(), fcntl()'s F_DUPFD should
  761          * return EINVAL when the new descriptor is out of bounds.
  762          */
  763         if (old < 0)
  764                 return (EBADF);
  765         if (new < 0)
  766                 return (flags & DUP_FCNTL ? EINVAL : EBADF);
  767         PROC_LOCK(p);
  768         maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
  769         PROC_UNLOCK(p);
  770         if (new >= maxfd)
  771                 return (flags & DUP_FCNTL ? EINVAL : EMFILE);
  772 
  773         FILEDESC_XLOCK(fdp);
  774         if (old >= fdp->fd_nfiles || fdp->fd_ofiles[old] == NULL) {
  775                 FILEDESC_XUNLOCK(fdp);
  776                 return (EBADF);
  777         }
  778         if (flags & DUP_FIXED && old == new) {
  779                 *retval = new;
  780                 FILEDESC_XUNLOCK(fdp);
  781                 return (0);
  782         }
  783         fp = fdp->fd_ofiles[old];
  784         fhold(fp);
  785 
  786         /*
  787          * If the caller specified a file descriptor, make sure the file
  788          * table is large enough to hold it, and grab it.  Otherwise, just
  789          * allocate a new descriptor the usual way.  Since the filedesc
  790          * lock may be temporarily dropped in the process, we have to look
  791          * out for a race.
  792          */
  793         if (flags & DUP_FIXED) {
  794                 if (new >= fdp->fd_nfiles)
  795                         fdgrowtable(fdp, new + 1);
  796                 if (fdp->fd_ofiles[new] == NULL)
  797                         fdused(fdp, new);
  798         } else {
  799                 if ((error = fdalloc(td, new, &new)) != 0) {
  800                         FILEDESC_XUNLOCK(fdp);
  801                         fdrop(fp, td);
  802                         return (error);
  803                 }
  804         }
  805 
  806         /*
  807          * If the old file changed out from under us then treat it as a
  808          * bad file descriptor.  Userland should do its own locking to
  809          * avoid this case.
  810          */
  811         if (fdp->fd_ofiles[old] != fp) {
  812                 /* we've allocated a descriptor which we won't use */
  813                 if (fdp->fd_ofiles[new] == NULL)
  814                         fdunused(fdp, new);
  815                 FILEDESC_XUNLOCK(fdp);
  816                 fdrop(fp, td);
  817                 return (EBADF);
  818         }
  819         KASSERT(old != new,
  820             ("new fd is same as old"));
  821 
  822         /*
  823          * Save info on the descriptor being overwritten.  We cannot close
  824          * it without introducing an ownership race for the slot, since we
  825          * need to drop the filedesc lock to call closef().
  826          *
  827          * XXX this duplicates parts of close().
  828          */
  829         delfp = fdp->fd_ofiles[new];
  830         holdleaders = 0;
  831         if (delfp != NULL) {
  832                 if (td->td_proc->p_fdtol != NULL) {
  833                         /*
  834                          * Ask fdfree() to sleep to ensure that all relevant
  835                          * process leaders can be traversed in closef().
  836                          */
  837                         fdp->fd_holdleaderscount++;
  838                         holdleaders = 1;
  839                 }
  840         }
  841 
  842         /*
  843          * Duplicate the source descriptor
  844          */
  845         fdp->fd_ofiles[new] = fp;
  846         fdp->fd_ofileflags[new] = fdp->fd_ofileflags[old] &~ UF_EXCLOSE;
  847         if (new > fdp->fd_lastfile)
  848                 fdp->fd_lastfile = new;
  849         *retval = new;
  850 
  851         /*
  852          * If we dup'd over a valid file, we now own the reference to it
  853          * and must dispose of it using closef() semantics (as if a
  854          * close() were performed on it).
  855          *
  856          * XXX this duplicates parts of close().
  857          */
  858         if (delfp != NULL) {
  859                 knote_fdclose(td, new);
  860                 if (delfp->f_type == DTYPE_MQUEUE)
  861                         mq_fdclose(td, new, delfp);
  862                 FILEDESC_XUNLOCK(fdp);
  863                 (void) closef(delfp, td);
  864                 if (holdleaders) {
  865                         FILEDESC_XLOCK(fdp);
  866                         fdp->fd_holdleaderscount--;
  867                         if (fdp->fd_holdleaderscount == 0 &&
  868                             fdp->fd_holdleaderswakeup != 0) {
  869                                 fdp->fd_holdleaderswakeup = 0;
  870                                 wakeup(&fdp->fd_holdleaderscount);
  871                         }
  872                         FILEDESC_XUNLOCK(fdp);
  873                 }
  874         } else {
  875                 FILEDESC_XUNLOCK(fdp);
  876         }
  877         return (0);
  878 }
  879 
  880 /*
  881  * If sigio is on the list associated with a process or process group,
  882  * disable signalling from the device, remove sigio from the list and
  883  * free sigio.
  884  */
  885 void
  886 funsetown(struct sigio **sigiop)
  887 {
  888         struct sigio *sigio;
  889 
  890         SIGIO_LOCK();
  891         sigio = *sigiop;
  892         if (sigio == NULL) {
  893                 SIGIO_UNLOCK();
  894                 return;
  895         }
  896         *(sigio->sio_myref) = NULL;
  897         if ((sigio)->sio_pgid < 0) {
  898                 struct pgrp *pg = (sigio)->sio_pgrp;
  899                 PGRP_LOCK(pg);
  900                 SLIST_REMOVE(&sigio->sio_pgrp->pg_sigiolst, sigio,
  901                              sigio, sio_pgsigio);
  902                 PGRP_UNLOCK(pg);
  903         } else {
  904                 struct proc *p = (sigio)->sio_proc;
  905                 PROC_LOCK(p);
  906                 SLIST_REMOVE(&sigio->sio_proc->p_sigiolst, sigio,
  907                              sigio, sio_pgsigio);
  908                 PROC_UNLOCK(p);
  909         }
  910         SIGIO_UNLOCK();
  911         crfree(sigio->sio_ucred);
  912         free(sigio, M_SIGIO);
  913 }
  914 
  915 /*
  916  * Free a list of sigio structures.
  917  * We only need to lock the SIGIO_LOCK because we have made ourselves
  918  * inaccessible to callers of fsetown and therefore do not need to lock
  919  * the proc or pgrp struct for the list manipulation.
  920  */
  921 void
  922 funsetownlst(struct sigiolst *sigiolst)
  923 {
  924         struct proc *p;
  925         struct pgrp *pg;
  926         struct sigio *sigio;
  927 
  928         sigio = SLIST_FIRST(sigiolst);
  929         if (sigio == NULL)
  930                 return;
  931         p = NULL;
  932         pg = NULL;
  933 
  934         /*
  935          * Every entry of the list should belong
  936          * to a single proc or pgrp.
  937          */
  938         if (sigio->sio_pgid < 0) {
  939                 pg = sigio->sio_pgrp;
  940                 PGRP_LOCK_ASSERT(pg, MA_NOTOWNED);
  941         } else /* if (sigio->sio_pgid > 0) */ {
  942                 p = sigio->sio_proc;
  943                 PROC_LOCK_ASSERT(p, MA_NOTOWNED);
  944         }
  945 
  946         SIGIO_LOCK();
  947         while ((sigio = SLIST_FIRST(sigiolst)) != NULL) {
  948                 *(sigio->sio_myref) = NULL;
  949                 if (pg != NULL) {
  950                         KASSERT(sigio->sio_pgid < 0,
  951                             ("Proc sigio in pgrp sigio list"));
  952                         KASSERT(sigio->sio_pgrp == pg,
  953                             ("Bogus pgrp in sigio list"));
  954                         PGRP_LOCK(pg);
  955                         SLIST_REMOVE(&pg->pg_sigiolst, sigio, sigio,
  956                             sio_pgsigio);
  957                         PGRP_UNLOCK(pg);
  958                 } else /* if (p != NULL) */ {
  959                         KASSERT(sigio->sio_pgid > 0,
  960                             ("Pgrp sigio in proc sigio list"));
  961                         KASSERT(sigio->sio_proc == p,
  962                             ("Bogus proc in sigio list"));
  963                         PROC_LOCK(p);
  964                         SLIST_REMOVE(&p->p_sigiolst, sigio, sigio,
  965                             sio_pgsigio);
  966                         PROC_UNLOCK(p);
  967                 }
  968                 SIGIO_UNLOCK();
  969                 crfree(sigio->sio_ucred);
  970                 free(sigio, M_SIGIO);
  971                 SIGIO_LOCK();
  972         }
  973         SIGIO_UNLOCK();
  974 }
  975 
  976 /*
  977  * This is common code for FIOSETOWN ioctl called by fcntl(fd, F_SETOWN, arg).
  978  *
  979  * After permission checking, add a sigio structure to the sigio list for
  980  * the process or process group.
  981  */
  982 int
  983 fsetown(pid_t pgid, struct sigio **sigiop)
  984 {
  985         struct proc *proc;
  986         struct pgrp *pgrp;
  987         struct sigio *sigio;
  988         int ret;
  989 
  990         if (pgid == 0) {
  991                 funsetown(sigiop);
  992                 return (0);
  993         }
  994 
  995         ret = 0;
  996 
  997         /* Allocate and fill in the new sigio out of locks. */
  998         sigio = malloc(sizeof(struct sigio), M_SIGIO, M_WAITOK);
  999         sigio->sio_pgid = pgid;
 1000         sigio->sio_ucred = crhold(curthread->td_ucred);
 1001         sigio->sio_myref = sigiop;
 1002 
 1003         sx_slock(&proctree_lock);
 1004         if (pgid > 0) {
 1005                 proc = pfind(pgid);
 1006                 if (proc == NULL) {
 1007                         ret = ESRCH;
 1008                         goto fail;
 1009                 }
 1010 
 1011                 /*
 1012                  * Policy - Don't allow a process to FSETOWN a process
 1013                  * in another session.
 1014                  *
 1015                  * Remove this test to allow maximum flexibility or
 1016                  * restrict FSETOWN to the current process or process
 1017                  * group for maximum safety.
 1018                  */
 1019                 PROC_UNLOCK(proc);
 1020                 if (proc->p_session != curthread->td_proc->p_session) {
 1021                         ret = EPERM;
 1022                         goto fail;
 1023                 }
 1024 
 1025                 pgrp = NULL;
 1026         } else /* if (pgid < 0) */ {
 1027                 pgrp = pgfind(-pgid);
 1028                 if (pgrp == NULL) {
 1029                         ret = ESRCH;
 1030                         goto fail;
 1031                 }
 1032                 PGRP_UNLOCK(pgrp);
 1033 
 1034                 /*
 1035                  * Policy - Don't allow a process to FSETOWN a process
 1036                  * in another session.
 1037                  *
 1038                  * Remove this test to allow maximum flexibility or
 1039                  * restrict FSETOWN to the current process or process
 1040                  * group for maximum safety.
 1041                  */
 1042                 if (pgrp->pg_session != curthread->td_proc->p_session) {
 1043                         ret = EPERM;
 1044                         goto fail;
 1045                 }
 1046 
 1047                 proc = NULL;
 1048         }
 1049         funsetown(sigiop);
 1050         if (pgid > 0) {
 1051                 PROC_LOCK(proc);
 1052                 /*
 1053                  * Since funsetownlst() is called without the proctree
 1054                  * locked, we need to check for P_WEXIT.
 1055                  * XXX: is ESRCH correct?
 1056                  */
 1057                 if ((proc->p_flag & P_WEXIT) != 0) {
 1058                         PROC_UNLOCK(proc);
 1059                         ret = ESRCH;
 1060                         goto fail;
 1061                 }
 1062                 SLIST_INSERT_HEAD(&proc->p_sigiolst, sigio, sio_pgsigio);
 1063                 sigio->sio_proc = proc;
 1064                 PROC_UNLOCK(proc);
 1065         } else {
 1066                 PGRP_LOCK(pgrp);
 1067                 SLIST_INSERT_HEAD(&pgrp->pg_sigiolst, sigio, sio_pgsigio);
 1068                 sigio->sio_pgrp = pgrp;
 1069                 PGRP_UNLOCK(pgrp);
 1070         }
 1071         sx_sunlock(&proctree_lock);
 1072         SIGIO_LOCK();
 1073         *sigiop = sigio;
 1074         SIGIO_UNLOCK();
 1075         return (0);
 1076 
 1077 fail:
 1078         sx_sunlock(&proctree_lock);
 1079         crfree(sigio->sio_ucred);
 1080         free(sigio, M_SIGIO);
 1081         return (ret);
 1082 }
 1083 
 1084 /*
 1085  * This is common code for FIOGETOWN ioctl called by fcntl(fd, F_GETOWN, arg).
 1086  */
 1087 pid_t
 1088 fgetown(sigiop)
 1089         struct sigio **sigiop;
 1090 {
 1091         pid_t pgid;
 1092 
 1093         SIGIO_LOCK();
 1094         pgid = (*sigiop != NULL) ? (*sigiop)->sio_pgid : 0;
 1095         SIGIO_UNLOCK();
 1096         return (pgid);
 1097 }
 1098 
 1099 /*
 1100  * Close a file descriptor.
 1101  */
 1102 #ifndef _SYS_SYSPROTO_H_
 1103 struct close_args {
 1104         int     fd;
 1105 };
 1106 #endif
 1107 /* ARGSUSED */
 1108 int
 1109 close(td, uap)
 1110         struct thread *td;
 1111         struct close_args *uap;
 1112 {
 1113 
 1114         return (kern_close(td, uap->fd));
 1115 }
 1116 
 1117 int
 1118 kern_close(td, fd)
 1119         struct thread *td;
 1120         int fd;
 1121 {
 1122         struct filedesc *fdp;
 1123         struct file *fp;
 1124         int error;
 1125         int holdleaders;
 1126 
 1127         error = 0;
 1128         holdleaders = 0;
 1129         fdp = td->td_proc->p_fd;
 1130 
 1131         AUDIT_SYSCLOSE(td, fd);
 1132 
 1133         FILEDESC_XLOCK(fdp);
 1134         if ((unsigned)fd >= fdp->fd_nfiles ||
 1135             (fp = fdp->fd_ofiles[fd]) == NULL) {
 1136                 FILEDESC_XUNLOCK(fdp);
 1137                 return (EBADF);
 1138         }
 1139         fdp->fd_ofiles[fd] = NULL;
 1140         fdp->fd_ofileflags[fd] = 0;
 1141         fdunused(fdp, fd);
 1142         if (td->td_proc->p_fdtol != NULL) {
 1143                 /*
 1144                  * Ask fdfree() to sleep to ensure that all relevant
 1145                  * process leaders can be traversed in closef().
 1146                  */
 1147                 fdp->fd_holdleaderscount++;
 1148                 holdleaders = 1;
 1149         }
 1150 
 1151         /*
 1152          * We now hold the fp reference that used to be owned by the
 1153          * descriptor array.  We have to unlock the FILEDESC *AFTER*
 1154          * knote_fdclose to prevent a race of the fd getting opened, a knote
 1155          * added, and deleteing a knote for the new fd.
 1156          */
 1157         knote_fdclose(td, fd);
 1158         if (fp->f_type == DTYPE_MQUEUE)
 1159                 mq_fdclose(td, fd, fp);
 1160         FILEDESC_XUNLOCK(fdp);
 1161 
 1162         error = closef(fp, td);
 1163         if (holdleaders) {
 1164                 FILEDESC_XLOCK(fdp);
 1165                 fdp->fd_holdleaderscount--;
 1166                 if (fdp->fd_holdleaderscount == 0 &&
 1167                     fdp->fd_holdleaderswakeup != 0) {
 1168                         fdp->fd_holdleaderswakeup = 0;
 1169                         wakeup(&fdp->fd_holdleaderscount);
 1170                 }
 1171                 FILEDESC_XUNLOCK(fdp);
 1172         }
 1173         return (error);
 1174 }
 1175 
 1176 /*
 1177  * Close open file descriptors.
 1178  */
 1179 #ifndef _SYS_SYSPROTO_H_
 1180 struct closefrom_args {
 1181         int     lowfd;
 1182 };
 1183 #endif
 1184 /* ARGSUSED */
 1185 int
 1186 closefrom(struct thread *td, struct closefrom_args *uap)
 1187 {
 1188         struct filedesc *fdp;
 1189         int fd;
 1190 
 1191         fdp = td->td_proc->p_fd;
 1192         AUDIT_ARG_FD(uap->lowfd);
 1193 
 1194         /*
 1195          * Treat negative starting file descriptor values identical to
 1196          * closefrom(0) which closes all files.
 1197          */
 1198         if (uap->lowfd < 0)
 1199                 uap->lowfd = 0;
 1200         FILEDESC_SLOCK(fdp);
 1201         for (fd = uap->lowfd; fd < fdp->fd_nfiles; fd++) {
 1202                 if (fdp->fd_ofiles[fd] != NULL) {
 1203                         FILEDESC_SUNLOCK(fdp);
 1204                         (void)kern_close(td, fd);
 1205                         FILEDESC_SLOCK(fdp);
 1206                 }
 1207         }
 1208         FILEDESC_SUNLOCK(fdp);
 1209         return (0);
 1210 }
 1211 
 1212 #if defined(COMPAT_43)
 1213 /*
 1214  * Return status information about a file descriptor.
 1215  */
 1216 #ifndef _SYS_SYSPROTO_H_
 1217 struct ofstat_args {
 1218         int     fd;
 1219         struct  ostat *sb;
 1220 };
 1221 #endif
 1222 /* ARGSUSED */
 1223 int
 1224 ofstat(struct thread *td, struct ofstat_args *uap)
 1225 {
 1226         struct ostat oub;
 1227         struct stat ub;
 1228         int error;
 1229 
 1230         error = kern_fstat(td, uap->fd, &ub);
 1231         if (error == 0) {
 1232                 cvtstat(&ub, &oub);
 1233                 error = copyout(&oub, uap->sb, sizeof(oub));
 1234         }
 1235         return (error);
 1236 }
 1237 #endif /* COMPAT_43 */
 1238 
 1239 /*
 1240  * Return status information about a file descriptor.
 1241  */
 1242 #ifndef _SYS_SYSPROTO_H_
 1243 struct fstat_args {
 1244         int     fd;
 1245         struct  stat *sb;
 1246 };
 1247 #endif
 1248 /* ARGSUSED */
 1249 int
 1250 fstat(struct thread *td, struct fstat_args *uap)
 1251 {
 1252         struct stat ub;
 1253         int error;
 1254 
 1255         error = kern_fstat(td, uap->fd, &ub);
 1256         if (error == 0)
 1257                 error = copyout(&ub, uap->sb, sizeof(ub));
 1258         return (error);
 1259 }
 1260 
 1261 int
 1262 kern_fstat(struct thread *td, int fd, struct stat *sbp)
 1263 {
 1264         struct file *fp;
 1265         int error;
 1266 
 1267         AUDIT_ARG_FD(fd);
 1268 
 1269         if ((error = fget(td, fd, &fp)) != 0)
 1270                 return (error);
 1271 
 1272         AUDIT_ARG_FILE(td->td_proc, fp);
 1273 
 1274         error = fo_stat(fp, sbp, td->td_ucred, td);
 1275         fdrop(fp, td);
 1276 #ifdef KTRACE
 1277         if (error == 0 && KTRPOINT(td, KTR_STRUCT))
 1278                 ktrstat(sbp);
 1279 #endif
 1280         return (error);
 1281 }
 1282 
 1283 /*
 1284  * Return status information about a file descriptor.
 1285  */
 1286 #ifndef _SYS_SYSPROTO_H_
 1287 struct nfstat_args {
 1288         int     fd;
 1289         struct  nstat *sb;
 1290 };
 1291 #endif
 1292 /* ARGSUSED */
 1293 int
 1294 nfstat(struct thread *td, struct nfstat_args *uap)
 1295 {
 1296         struct nstat nub;
 1297         struct stat ub;
 1298         int error;
 1299 
 1300         error = kern_fstat(td, uap->fd, &ub);
 1301         if (error == 0) {
 1302                 cvtnstat(&ub, &nub);
 1303                 error = copyout(&nub, uap->sb, sizeof(nub));
 1304         }
 1305         return (error);
 1306 }
 1307 
 1308 /*
 1309  * Return pathconf information about a file descriptor.
 1310  */
 1311 #ifndef _SYS_SYSPROTO_H_
 1312 struct fpathconf_args {
 1313         int     fd;
 1314         int     name;
 1315 };
 1316 #endif
 1317 /* ARGSUSED */
 1318 int
 1319 fpathconf(struct thread *td, struct fpathconf_args *uap)
 1320 {
 1321         struct file *fp;
 1322         struct vnode *vp;
 1323         int error;
 1324 
 1325         if ((error = fget(td, uap->fd, &fp)) != 0)
 1326                 return (error);
 1327 
 1328         /* If asynchronous I/O is available, it works for all descriptors. */
 1329         if (uap->name == _PC_ASYNC_IO) {
 1330                 td->td_retval[0] = async_io_version;
 1331                 goto out;
 1332         }
 1333         vp = fp->f_vnode;
 1334         if (vp != NULL) {
 1335                 int vfslocked;
 1336                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 1337                 vn_lock(vp, LK_SHARED | LK_RETRY);
 1338                 error = VOP_PATHCONF(vp, uap->name, td->td_retval);
 1339                 VOP_UNLOCK(vp, 0);
 1340                 VFS_UNLOCK_GIANT(vfslocked);
 1341         } else if (fp->f_type == DTYPE_PIPE || fp->f_type == DTYPE_SOCKET) {
 1342                 if (uap->name != _PC_PIPE_BUF) {
 1343                         error = EINVAL;
 1344                 } else {
 1345                         td->td_retval[0] = PIPE_BUF;
 1346                 error = 0;
 1347                 }
 1348         } else {
 1349                 error = EOPNOTSUPP;
 1350         }
 1351 out:
 1352         fdrop(fp, td);
 1353         return (error);
 1354 }
 1355 
 1356 /*
 1357  * Grow the file table to accomodate (at least) nfd descriptors.  This may
 1358  * block and drop the filedesc lock, but it will reacquire it before
 1359  * returning.
 1360  */
 1361 static void
 1362 fdgrowtable(struct filedesc *fdp, int nfd)
 1363 {
 1364         struct filedesc0 *fdp0;
 1365         struct freetable *fo;
 1366         struct file **ntable;
 1367         struct file **otable;
 1368         char *nfileflags;
 1369         int nnfiles, onfiles;
 1370         NDSLOTTYPE *nmap;
 1371 
 1372         FILEDESC_XLOCK_ASSERT(fdp);
 1373 
 1374         KASSERT(fdp->fd_nfiles > 0,
 1375             ("zero-length file table"));
 1376 
 1377         /* compute the size of the new table */
 1378         onfiles = fdp->fd_nfiles;
 1379         nnfiles = NDSLOTS(nfd) * NDENTRIES; /* round up */
 1380         if (nnfiles <= onfiles)
 1381                 /* the table is already large enough */
 1382                 return;
 1383 
 1384         /* allocate a new table and (if required) new bitmaps */
 1385         FILEDESC_XUNLOCK(fdp);
 1386         ntable = malloc((nnfiles * OFILESIZE) + sizeof(struct freetable),
 1387             M_FILEDESC, M_ZERO | M_WAITOK);
 1388         nfileflags = (char *)&ntable[nnfiles];
 1389         if (NDSLOTS(nnfiles) > NDSLOTS(onfiles))
 1390                 nmap = malloc(NDSLOTS(nnfiles) * NDSLOTSIZE,
 1391                     M_FILEDESC, M_ZERO | M_WAITOK);
 1392         else
 1393                 nmap = NULL;
 1394         FILEDESC_XLOCK(fdp);
 1395 
 1396         /*
 1397          * We now have new tables ready to go.  Since we dropped the
 1398          * filedesc lock to call malloc(), watch out for a race.
 1399          */
 1400         onfiles = fdp->fd_nfiles;
 1401         if (onfiles >= nnfiles) {
 1402                 /* we lost the race, but that's OK */
 1403                 free(ntable, M_FILEDESC);
 1404                 if (nmap != NULL)
 1405                         free(nmap, M_FILEDESC);
 1406                 return;
 1407         }
 1408         bcopy(fdp->fd_ofiles, ntable, onfiles * sizeof(*ntable));
 1409         bcopy(fdp->fd_ofileflags, nfileflags, onfiles);
 1410         otable = fdp->fd_ofiles;
 1411         fdp->fd_ofileflags = nfileflags;
 1412         fdp->fd_ofiles = ntable;
 1413         /*
 1414          * We must preserve ofiles until the process exits because we can't
 1415          * be certain that no threads have references to the old table via
 1416          * _fget().
 1417          */
 1418         if (onfiles > NDFILE) {
 1419                 fo = (struct freetable *)&otable[onfiles];
 1420                 fdp0 = (struct filedesc0 *)fdp;
 1421                 fo->ft_table = otable;
 1422                 SLIST_INSERT_HEAD(&fdp0->fd_free, fo, ft_next);
 1423         }
 1424         if (NDSLOTS(nnfiles) > NDSLOTS(onfiles)) {
 1425                 bcopy(fdp->fd_map, nmap, NDSLOTS(onfiles) * sizeof(*nmap));
 1426                 if (NDSLOTS(onfiles) > NDSLOTS(NDFILE))
 1427                         free(fdp->fd_map, M_FILEDESC);
 1428                 fdp->fd_map = nmap;
 1429         }
 1430         fdp->fd_nfiles = nnfiles;
 1431 }
 1432 
 1433 /*
 1434  * Allocate a file descriptor for the process.
 1435  */
 1436 int
 1437 fdalloc(struct thread *td, int minfd, int *result)
 1438 {
 1439         struct proc *p = td->td_proc;
 1440         struct filedesc *fdp = p->p_fd;
 1441         int fd = -1, maxfd;
 1442 
 1443         FILEDESC_XLOCK_ASSERT(fdp);
 1444 
 1445         if (fdp->fd_freefile > minfd)
 1446                 minfd = fdp->fd_freefile;          
 1447 
 1448         PROC_LOCK(p);
 1449         maxfd = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
 1450         PROC_UNLOCK(p);
 1451 
 1452         /*
 1453          * Search the bitmap for a free descriptor.  If none is found, try
 1454          * to grow the file table.  Keep at it until we either get a file
 1455          * descriptor or run into process or system limits; fdgrowtable()
 1456          * may drop the filedesc lock, so we're in a race.
 1457          */
 1458         for (;;) {
 1459                 fd = fd_first_free(fdp, minfd, fdp->fd_nfiles);
 1460                 if (fd >= maxfd)
 1461                         return (EMFILE);
 1462                 if (fd < fdp->fd_nfiles)
 1463                         break;
 1464                 fdgrowtable(fdp, min(fdp->fd_nfiles * 2, maxfd));
 1465         }
 1466 
 1467         /*
 1468          * Perform some sanity checks, then mark the file descriptor as
 1469          * used and return it to the caller.
 1470          */
 1471         KASSERT(!fdisused(fdp, fd),
 1472             ("fd_first_free() returned non-free descriptor"));
 1473         KASSERT(fdp->fd_ofiles[fd] == NULL,
 1474             ("free descriptor isn't"));
 1475         fdp->fd_ofileflags[fd] = 0; /* XXX needed? */
 1476         fdused(fdp, fd);
 1477         *result = fd;
 1478         return (0);
 1479 }
 1480 
 1481 /*
 1482  * Check to see whether n user file descriptors are available to the process
 1483  * p.
 1484  */
 1485 int
 1486 fdavail(struct thread *td, int n)
 1487 {
 1488         struct proc *p = td->td_proc;
 1489         struct filedesc *fdp = td->td_proc->p_fd;
 1490         struct file **fpp;
 1491         int i, lim, last;
 1492 
 1493         FILEDESC_LOCK_ASSERT(fdp);
 1494 
 1495         PROC_LOCK(p);
 1496         lim = min((int)lim_cur(p, RLIMIT_NOFILE), maxfilesperproc);
 1497         PROC_UNLOCK(p);
 1498         if ((i = lim - fdp->fd_nfiles) > 0 && (n -= i) <= 0)
 1499                 return (1);
 1500         last = min(fdp->fd_nfiles, lim);
 1501         fpp = &fdp->fd_ofiles[fdp->fd_freefile];
 1502         for (i = last - fdp->fd_freefile; --i >= 0; fpp++) {
 1503                 if (*fpp == NULL && --n <= 0)
 1504                         return (1);
 1505         }
 1506         return (0);
 1507 }
 1508 
 1509 /*
 1510  * Create a new open file structure and allocate a file decriptor for the
 1511  * process that refers to it.  We add one reference to the file for the
 1512  * descriptor table and one reference for resultfp. This is to prevent us
 1513  * being preempted and the entry in the descriptor table closed after we
 1514  * release the FILEDESC lock.
 1515  */
 1516 int
 1517 falloc(struct thread *td, struct file **resultfp, int *resultfd)
 1518 {
 1519         struct proc *p = td->td_proc;
 1520         struct file *fp;
 1521         int error, i;
 1522         int maxuserfiles = maxfiles - (maxfiles / 20);
 1523         static struct timeval lastfail;
 1524         static int curfail;
 1525 
 1526         fp = uma_zalloc(file_zone, M_WAITOK | M_ZERO);
 1527         if ((openfiles >= maxuserfiles &&
 1528             priv_check(td, PRIV_MAXFILES) != 0) ||
 1529             openfiles >= maxfiles) {
 1530                 if (ppsratecheck(&lastfail, &curfail, 1)) {
 1531                         printf("kern.maxfiles limit exceeded by uid %i, please see tuning(7).\n",
 1532                                 td->td_ucred->cr_ruid);
 1533                 }
 1534                 uma_zfree(file_zone, fp);
 1535                 return (ENFILE);
 1536         }
 1537         atomic_add_int(&openfiles, 1);
 1538 
 1539         /*
 1540          * If the process has file descriptor zero open, add the new file
 1541          * descriptor to the list of open files at that point, otherwise
 1542          * put it at the front of the list of open files.
 1543          */
 1544         refcount_init(&fp->f_count, 1);
 1545         if (resultfp)
 1546                 fhold(fp);
 1547         fp->f_cred = crhold(td->td_ucred);
 1548         fp->f_ops = &badfileops;
 1549         fp->f_data = NULL;
 1550         fp->f_vnode = NULL;
 1551         FILEDESC_XLOCK(p->p_fd);
 1552         if ((error = fdalloc(td, 0, &i))) {
 1553                 FILEDESC_XUNLOCK(p->p_fd);
 1554                 fdrop(fp, td);
 1555                 if (resultfp)
 1556                         fdrop(fp, td);
 1557                 return (error);
 1558         }
 1559         p->p_fd->fd_ofiles[i] = fp;
 1560         FILEDESC_XUNLOCK(p->p_fd);
 1561         if (resultfp)
 1562                 *resultfp = fp;
 1563         if (resultfd)
 1564                 *resultfd = i;
 1565         return (0);
 1566 }
 1567 
 1568 /*
 1569  * Build a new filedesc structure from another.
 1570  * Copy the current, root, and jail root vnode references.
 1571  */
 1572 struct filedesc *
 1573 fdinit(struct filedesc *fdp)
 1574 {
 1575         struct filedesc0 *newfdp;
 1576 
 1577         newfdp = malloc(sizeof *newfdp, M_FILEDESC, M_WAITOK | M_ZERO);
 1578         FILEDESC_LOCK_INIT(&newfdp->fd_fd);
 1579         if (fdp != NULL) {
 1580                 FILEDESC_XLOCK(fdp);
 1581                 newfdp->fd_fd.fd_cdir = fdp->fd_cdir;
 1582                 if (newfdp->fd_fd.fd_cdir)
 1583                         VREF(newfdp->fd_fd.fd_cdir);
 1584                 newfdp->fd_fd.fd_rdir = fdp->fd_rdir;
 1585                 if (newfdp->fd_fd.fd_rdir)
 1586                         VREF(newfdp->fd_fd.fd_rdir);
 1587                 newfdp->fd_fd.fd_jdir = fdp->fd_jdir;
 1588                 if (newfdp->fd_fd.fd_jdir)
 1589                         VREF(newfdp->fd_fd.fd_jdir);
 1590                 FILEDESC_XUNLOCK(fdp);
 1591         }
 1592 
 1593         /* Create the file descriptor table. */
 1594         newfdp->fd_fd.fd_refcnt = 1;
 1595         newfdp->fd_fd.fd_holdcnt = 1;
 1596         newfdp->fd_fd.fd_cmask = CMASK;
 1597         newfdp->fd_fd.fd_ofiles = newfdp->fd_dfiles;
 1598         newfdp->fd_fd.fd_ofileflags = newfdp->fd_dfileflags;
 1599         newfdp->fd_fd.fd_nfiles = NDFILE;
 1600         newfdp->fd_fd.fd_map = newfdp->fd_dmap;
 1601         newfdp->fd_fd.fd_lastfile = -1;
 1602         return (&newfdp->fd_fd);
 1603 }
 1604 
 1605 static struct filedesc *
 1606 fdhold(struct proc *p)
 1607 {
 1608         struct filedesc *fdp;
 1609 
 1610         mtx_lock(&fdesc_mtx);
 1611         fdp = p->p_fd;
 1612         if (fdp != NULL)
 1613                 fdp->fd_holdcnt++;
 1614         mtx_unlock(&fdesc_mtx);
 1615         return (fdp);
 1616 }
 1617 
 1618 static void
 1619 fddrop(struct filedesc *fdp)
 1620 {
 1621         struct filedesc0 *fdp0;
 1622         struct freetable *ft;
 1623         int i;
 1624 
 1625         mtx_lock(&fdesc_mtx);
 1626         i = --fdp->fd_holdcnt;
 1627         mtx_unlock(&fdesc_mtx);
 1628         if (i > 0)
 1629                 return;
 1630 
 1631         FILEDESC_LOCK_DESTROY(fdp);
 1632         fdp0 = (struct filedesc0 *)fdp;
 1633         while ((ft = SLIST_FIRST(&fdp0->fd_free)) != NULL) {
 1634                 SLIST_REMOVE_HEAD(&fdp0->fd_free, ft_next);
 1635                 free(ft->ft_table, M_FILEDESC);
 1636         }
 1637         free(fdp, M_FILEDESC);
 1638 }
 1639 
 1640 /*
 1641  * Share a filedesc structure.
 1642  */
 1643 struct filedesc *
 1644 fdshare(struct filedesc *fdp)
 1645 {
 1646 
 1647         FILEDESC_XLOCK(fdp);
 1648         fdp->fd_refcnt++;
 1649         FILEDESC_XUNLOCK(fdp);
 1650         return (fdp);
 1651 }
 1652 
 1653 /*
 1654  * Unshare a filedesc structure, if necessary by making a copy
 1655  */
 1656 void
 1657 fdunshare(struct proc *p, struct thread *td)
 1658 {
 1659 
 1660         FILEDESC_XLOCK(p->p_fd);
 1661         if (p->p_fd->fd_refcnt > 1) {
 1662                 struct filedesc *tmp;
 1663 
 1664                 FILEDESC_XUNLOCK(p->p_fd);
 1665                 tmp = fdcopy(p->p_fd);
 1666                 fdfree(td);
 1667                 p->p_fd = tmp;
 1668         } else
 1669                 FILEDESC_XUNLOCK(p->p_fd);
 1670 }
 1671 
 1672 /*
 1673  * Copy a filedesc structure.  A NULL pointer in returns a NULL reference,
 1674  * this is to ease callers, not catch errors.
 1675  */
 1676 struct filedesc *
 1677 fdcopy(struct filedesc *fdp)
 1678 {
 1679         struct filedesc *newfdp;
 1680         int i;
 1681 
 1682         /* Certain daemons might not have file descriptors. */
 1683         if (fdp == NULL)
 1684                 return (NULL);
 1685 
 1686         newfdp = fdinit(fdp);
 1687         FILEDESC_SLOCK(fdp);
 1688         while (fdp->fd_lastfile >= newfdp->fd_nfiles) {
 1689                 FILEDESC_SUNLOCK(fdp);
 1690                 FILEDESC_XLOCK(newfdp);
 1691                 fdgrowtable(newfdp, fdp->fd_lastfile + 1);
 1692                 FILEDESC_XUNLOCK(newfdp);
 1693                 FILEDESC_SLOCK(fdp);
 1694         }
 1695         /* copy everything except kqueue descriptors */
 1696         newfdp->fd_freefile = -1;
 1697         for (i = 0; i <= fdp->fd_lastfile; ++i) {
 1698                 if (fdisused(fdp, i) &&
 1699                     fdp->fd_ofiles[i]->f_type != DTYPE_KQUEUE &&
 1700                     fdp->fd_ofiles[i]->f_ops != &badfileops) {
 1701                         newfdp->fd_ofiles[i] = fdp->fd_ofiles[i];
 1702                         newfdp->fd_ofileflags[i] = fdp->fd_ofileflags[i];
 1703                         fhold(newfdp->fd_ofiles[i]);
 1704                         newfdp->fd_lastfile = i;
 1705                 } else {
 1706                         if (newfdp->fd_freefile == -1)
 1707                                 newfdp->fd_freefile = i;
 1708                 }
 1709         }
 1710         newfdp->fd_cmask = fdp->fd_cmask;
 1711         FILEDESC_SUNLOCK(fdp);
 1712         FILEDESC_XLOCK(newfdp);
 1713         for (i = 0; i <= newfdp->fd_lastfile; ++i)
 1714                 if (newfdp->fd_ofiles[i] != NULL)
 1715                         fdused(newfdp, i);
 1716         if (newfdp->fd_freefile == -1)
 1717                 newfdp->fd_freefile = i;
 1718         FILEDESC_XUNLOCK(newfdp);
 1719         return (newfdp);
 1720 }
 1721 
 1722 /*
 1723  * Release a filedesc structure.
 1724  */
 1725 void
 1726 fdfree(struct thread *td)
 1727 {
 1728         struct filedesc *fdp;
 1729         struct file **fpp;
 1730         int i, locked;
 1731         struct filedesc_to_leader *fdtol;
 1732         struct file *fp;
 1733         struct vnode *cdir, *jdir, *rdir, *vp;
 1734         struct flock lf;
 1735 
 1736         /* Certain daemons might not have file descriptors. */
 1737         fdp = td->td_proc->p_fd;
 1738         if (fdp == NULL)
 1739                 return;
 1740 
 1741         /* Check for special need to clear POSIX style locks */
 1742         fdtol = td->td_proc->p_fdtol;
 1743         if (fdtol != NULL) {
 1744                 FILEDESC_XLOCK(fdp);
 1745                 KASSERT(fdtol->fdl_refcount > 0,
 1746                         ("filedesc_to_refcount botch: fdl_refcount=%d",
 1747                          fdtol->fdl_refcount));
 1748                 if (fdtol->fdl_refcount == 1 &&
 1749                     (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
 1750                         for (i = 0, fpp = fdp->fd_ofiles;
 1751                              i <= fdp->fd_lastfile;
 1752                              i++, fpp++) {
 1753                                 if (*fpp == NULL ||
 1754                                     (*fpp)->f_type != DTYPE_VNODE)
 1755                                         continue;
 1756                                 fp = *fpp;
 1757                                 fhold(fp);
 1758                                 FILEDESC_XUNLOCK(fdp);
 1759                                 lf.l_whence = SEEK_SET;
 1760                                 lf.l_start = 0;
 1761                                 lf.l_len = 0;
 1762                                 lf.l_type = F_UNLCK;
 1763                                 vp = fp->f_vnode;
 1764                                 locked = VFS_LOCK_GIANT(vp->v_mount);
 1765                                 (void) VOP_ADVLOCK(vp,
 1766                                                    (caddr_t)td->td_proc->
 1767                                                    p_leader,
 1768                                                    F_UNLCK,
 1769                                                    &lf,
 1770                                                    F_POSIX);
 1771                                 VFS_UNLOCK_GIANT(locked);
 1772                                 FILEDESC_XLOCK(fdp);
 1773                                 fdrop(fp, td);
 1774                                 fpp = fdp->fd_ofiles + i;
 1775                         }
 1776                 }
 1777         retry:
 1778                 if (fdtol->fdl_refcount == 1) {
 1779                         if (fdp->fd_holdleaderscount > 0 &&
 1780                             (td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
 1781                                 /*
 1782                                  * close() or do_dup() has cleared a reference
 1783                                  * in a shared file descriptor table.
 1784                                  */
 1785                                 fdp->fd_holdleaderswakeup = 1;
 1786                                 sx_sleep(&fdp->fd_holdleaderscount,
 1787                                     FILEDESC_LOCK(fdp), PLOCK, "fdlhold", 0);
 1788                                 goto retry;
 1789                         }
 1790                         if (fdtol->fdl_holdcount > 0) {
 1791                                 /*
 1792                                  * Ensure that fdtol->fdl_leader remains
 1793                                  * valid in closef().
 1794                                  */
 1795                                 fdtol->fdl_wakeup = 1;
 1796                                 sx_sleep(fdtol, FILEDESC_LOCK(fdp), PLOCK,
 1797                                     "fdlhold", 0);
 1798                                 goto retry;
 1799                         }
 1800                 }
 1801                 fdtol->fdl_refcount--;
 1802                 if (fdtol->fdl_refcount == 0 &&
 1803                     fdtol->fdl_holdcount == 0) {
 1804                         fdtol->fdl_next->fdl_prev = fdtol->fdl_prev;
 1805                         fdtol->fdl_prev->fdl_next = fdtol->fdl_next;
 1806                 } else
 1807                         fdtol = NULL;
 1808                 td->td_proc->p_fdtol = NULL;
 1809                 FILEDESC_XUNLOCK(fdp);
 1810                 if (fdtol != NULL)
 1811                         free(fdtol, M_FILEDESC_TO_LEADER);
 1812         }
 1813         FILEDESC_XLOCK(fdp);
 1814         i = --fdp->fd_refcnt;
 1815         FILEDESC_XUNLOCK(fdp);
 1816         if (i > 0)
 1817                 return;
 1818 
 1819         fpp = fdp->fd_ofiles;
 1820         for (i = fdp->fd_lastfile; i-- >= 0; fpp++) {
 1821                 if (*fpp) {
 1822                         FILEDESC_XLOCK(fdp);
 1823                         fp = *fpp;
 1824                         *fpp = NULL;
 1825                         FILEDESC_XUNLOCK(fdp);
 1826                         (void) closef(fp, td);
 1827                 }
 1828         }
 1829         FILEDESC_XLOCK(fdp);
 1830 
 1831         /* XXX This should happen earlier. */
 1832         mtx_lock(&fdesc_mtx);
 1833         td->td_proc->p_fd = NULL;
 1834         mtx_unlock(&fdesc_mtx);
 1835 
 1836         if (fdp->fd_nfiles > NDFILE)
 1837                 free(fdp->fd_ofiles, M_FILEDESC);
 1838         if (NDSLOTS(fdp->fd_nfiles) > NDSLOTS(NDFILE))
 1839                 free(fdp->fd_map, M_FILEDESC);
 1840 
 1841         fdp->fd_nfiles = 0;
 1842 
 1843         cdir = fdp->fd_cdir;
 1844         fdp->fd_cdir = NULL;
 1845         rdir = fdp->fd_rdir;
 1846         fdp->fd_rdir = NULL;
 1847         jdir = fdp->fd_jdir;
 1848         fdp->fd_jdir = NULL;
 1849         FILEDESC_XUNLOCK(fdp);
 1850 
 1851         if (cdir) {
 1852                 locked = VFS_LOCK_GIANT(cdir->v_mount);
 1853                 vrele(cdir);
 1854                 VFS_UNLOCK_GIANT(locked);
 1855         }
 1856         if (rdir) {
 1857                 locked = VFS_LOCK_GIANT(rdir->v_mount);
 1858                 vrele(rdir);
 1859                 VFS_UNLOCK_GIANT(locked);
 1860         }
 1861         if (jdir) {
 1862                 locked = VFS_LOCK_GIANT(jdir->v_mount);
 1863                 vrele(jdir);
 1864                 VFS_UNLOCK_GIANT(locked);
 1865         }
 1866 
 1867         fddrop(fdp);
 1868 }
 1869 
 1870 /*
 1871  * For setugid programs, we don't want to people to use that setugidness
 1872  * to generate error messages which write to a file which otherwise would
 1873  * otherwise be off-limits to the process.  We check for filesystems where
 1874  * the vnode can change out from under us after execve (like [lin]procfs).
 1875  *
 1876  * Since setugidsafety calls this only for fd 0, 1 and 2, this check is
 1877  * sufficient.  We also don't check for setugidness since we know we are.
 1878  */
 1879 static int
 1880 is_unsafe(struct file *fp)
 1881 {
 1882         if (fp->f_type == DTYPE_VNODE) {
 1883                 struct vnode *vp = fp->f_vnode;
 1884 
 1885                 if ((vp->v_vflag & VV_PROCDEP) != 0)
 1886                         return (1);
 1887         }
 1888         return (0);
 1889 }
 1890 
 1891 /*
 1892  * Make this setguid thing safe, if at all possible.
 1893  */
 1894 void
 1895 setugidsafety(struct thread *td)
 1896 {
 1897         struct filedesc *fdp;
 1898         int i;
 1899 
 1900         /* Certain daemons might not have file descriptors. */
 1901         fdp = td->td_proc->p_fd;
 1902         if (fdp == NULL)
 1903                 return;
 1904 
 1905         /*
 1906          * Note: fdp->fd_ofiles may be reallocated out from under us while
 1907          * we are blocked in a close.  Be careful!
 1908          */
 1909         FILEDESC_XLOCK(fdp);
 1910         for (i = 0; i <= fdp->fd_lastfile; i++) {
 1911                 if (i > 2)
 1912                         break;
 1913                 if (fdp->fd_ofiles[i] && is_unsafe(fdp->fd_ofiles[i])) {
 1914                         struct file *fp;
 1915 
 1916                         knote_fdclose(td, i);
 1917                         /*
 1918                          * NULL-out descriptor prior to close to avoid
 1919                          * a race while close blocks.
 1920                          */
 1921                         fp = fdp->fd_ofiles[i];
 1922                         fdp->fd_ofiles[i] = NULL;
 1923                         fdp->fd_ofileflags[i] = 0;
 1924                         fdunused(fdp, i);
 1925                         FILEDESC_XUNLOCK(fdp);
 1926                         (void) closef(fp, td);
 1927                         FILEDESC_XLOCK(fdp);
 1928                 }
 1929         }
 1930         FILEDESC_XUNLOCK(fdp);
 1931 }
 1932 
 1933 /*
 1934  * If a specific file object occupies a specific file descriptor, close the
 1935  * file descriptor entry and drop a reference on the file object.  This is a
 1936  * convenience function to handle a subsequent error in a function that calls
 1937  * falloc() that handles the race that another thread might have closed the
 1938  * file descriptor out from under the thread creating the file object.
 1939  */
 1940 void
 1941 fdclose(struct filedesc *fdp, struct file *fp, int idx, struct thread *td)
 1942 {
 1943 
 1944         FILEDESC_XLOCK(fdp);
 1945         if (fdp->fd_ofiles[idx] == fp) {
 1946                 fdp->fd_ofiles[idx] = NULL;
 1947                 fdunused(fdp, idx);
 1948                 FILEDESC_XUNLOCK(fdp);
 1949                 fdrop(fp, td);
 1950         } else
 1951                 FILEDESC_XUNLOCK(fdp);
 1952 }
 1953 
 1954 /*
 1955  * Close any files on exec?
 1956  */
 1957 void
 1958 fdcloseexec(struct thread *td)
 1959 {
 1960         struct filedesc *fdp;
 1961         int i;
 1962 
 1963         /* Certain daemons might not have file descriptors. */
 1964         fdp = td->td_proc->p_fd;
 1965         if (fdp == NULL)
 1966                 return;
 1967 
 1968         FILEDESC_XLOCK(fdp);
 1969 
 1970         /*
 1971          * We cannot cache fd_ofiles or fd_ofileflags since operations
 1972          * may block and rip them out from under us.
 1973          */
 1974         for (i = 0; i <= fdp->fd_lastfile; i++) {
 1975                 if (fdp->fd_ofiles[i] != NULL &&
 1976                     (fdp->fd_ofiles[i]->f_type == DTYPE_MQUEUE ||
 1977                     (fdp->fd_ofileflags[i] & UF_EXCLOSE))) {
 1978                         struct file *fp;
 1979 
 1980                         knote_fdclose(td, i);
 1981                         /*
 1982                          * NULL-out descriptor prior to close to avoid
 1983                          * a race while close blocks.
 1984                          */
 1985                         fp = fdp->fd_ofiles[i];
 1986                         fdp->fd_ofiles[i] = NULL;
 1987                         fdp->fd_ofileflags[i] = 0;
 1988                         fdunused(fdp, i);
 1989                         if (fp->f_type == DTYPE_MQUEUE)
 1990                                 mq_fdclose(td, i, fp);
 1991                         FILEDESC_XUNLOCK(fdp);
 1992                         (void) closef(fp, td);
 1993                         FILEDESC_XLOCK(fdp);
 1994                 }
 1995         }
 1996         FILEDESC_XUNLOCK(fdp);
 1997 }
 1998 
 1999 /*
 2000  * It is unsafe for set[ug]id processes to be started with file
 2001  * descriptors 0..2 closed, as these descriptors are given implicit
 2002  * significance in the Standard C library.  fdcheckstd() will create a
 2003  * descriptor referencing /dev/null for each of stdin, stdout, and
 2004  * stderr that is not already open.
 2005  */
 2006 int
 2007 fdcheckstd(struct thread *td)
 2008 {
 2009         struct filedesc *fdp;
 2010         register_t retval, save;
 2011         int i, error, devnull;
 2012 
 2013         fdp = td->td_proc->p_fd;
 2014         if (fdp == NULL)
 2015                 return (0);
 2016         KASSERT(fdp->fd_refcnt == 1, ("the fdtable should not be shared"));
 2017         devnull = -1;
 2018         error = 0;
 2019         for (i = 0; i < 3; i++) {
 2020                 if (fdp->fd_ofiles[i] != NULL)
 2021                         continue;
 2022                 if (devnull < 0) {
 2023                         save = td->td_retval[0];
 2024                         error = kern_open(td, "/dev/null", UIO_SYSSPACE,
 2025                             O_RDWR, 0);
 2026                         devnull = td->td_retval[0];
 2027                         KASSERT(devnull == i, ("oof, we didn't get our fd"));
 2028                         td->td_retval[0] = save;
 2029                         if (error)
 2030                                 break;
 2031                 } else {
 2032                         error = do_dup(td, DUP_FIXED, devnull, i, &retval);
 2033                         if (error != 0)
 2034                                 break;
 2035                 }
 2036         }
 2037         return (error);
 2038 }
 2039 
 2040 /*
 2041  * Internal form of close.  Decrement reference count on file structure.
 2042  * Note: td may be NULL when closing a file that was being passed in a
 2043  * message.
 2044  *
 2045  * XXXRW: Giant is not required for the caller, but often will be held; this
 2046  * makes it moderately likely the Giant will be recursed in the VFS case.
 2047  */
 2048 int
 2049 closef(struct file *fp, struct thread *td)
 2050 {
 2051         struct vnode *vp;
 2052         struct flock lf;
 2053         struct filedesc_to_leader *fdtol;
 2054         struct filedesc *fdp;
 2055 
 2056         /*
 2057          * POSIX record locking dictates that any close releases ALL
 2058          * locks owned by this process.  This is handled by setting
 2059          * a flag in the unlock to free ONLY locks obeying POSIX
 2060          * semantics, and not to free BSD-style file locks.
 2061          * If the descriptor was in a message, POSIX-style locks
 2062          * aren't passed with the descriptor, and the thread pointer
 2063          * will be NULL.  Callers should be careful only to pass a
 2064          * NULL thread pointer when there really is no owning
 2065          * context that might have locks, or the locks will be
 2066          * leaked.
 2067          */
 2068         if (fp->f_type == DTYPE_VNODE && td != NULL) {
 2069                 int vfslocked;
 2070 
 2071                 vp = fp->f_vnode;
 2072                 vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 2073                 if ((td->td_proc->p_leader->p_flag & P_ADVLOCK) != 0) {
 2074                         lf.l_whence = SEEK_SET;
 2075                         lf.l_start = 0;
 2076                         lf.l_len = 0;
 2077                         lf.l_type = F_UNLCK;
 2078                         (void) VOP_ADVLOCK(vp, (caddr_t)td->td_proc->p_leader,
 2079                                            F_UNLCK, &lf, F_POSIX);
 2080                 }
 2081                 fdtol = td->td_proc->p_fdtol;
 2082                 if (fdtol != NULL) {
 2083                         /*
 2084                          * Handle special case where file descriptor table is
 2085                          * shared between multiple process leaders.
 2086                          */
 2087                         fdp = td->td_proc->p_fd;
 2088                         FILEDESC_XLOCK(fdp);
 2089                         for (fdtol = fdtol->fdl_next;
 2090                              fdtol != td->td_proc->p_fdtol;
 2091                              fdtol = fdtol->fdl_next) {
 2092                                 if ((fdtol->fdl_leader->p_flag &
 2093                                      P_ADVLOCK) == 0)
 2094                                         continue;
 2095                                 fdtol->fdl_holdcount++;
 2096                                 FILEDESC_XUNLOCK(fdp);
 2097                                 lf.l_whence = SEEK_SET;
 2098                                 lf.l_start = 0;
 2099                                 lf.l_len = 0;
 2100                                 lf.l_type = F_UNLCK;
 2101                                 vp = fp->f_vnode;
 2102                                 (void) VOP_ADVLOCK(vp,
 2103                                                    (caddr_t)fdtol->fdl_leader,
 2104                                                    F_UNLCK, &lf, F_POSIX);
 2105                                 FILEDESC_XLOCK(fdp);
 2106                                 fdtol->fdl_holdcount--;
 2107                                 if (fdtol->fdl_holdcount == 0 &&
 2108                                     fdtol->fdl_wakeup != 0) {
 2109                                         fdtol->fdl_wakeup = 0;
 2110                                         wakeup(fdtol);
 2111                                 }
 2112                         }
 2113                         FILEDESC_XUNLOCK(fdp);
 2114                 }
 2115                 VFS_UNLOCK_GIANT(vfslocked);
 2116         }
 2117         return (fdrop(fp, td));
 2118 }
 2119 
 2120 /*
 2121  * Initialize the file pointer with the specified properties.
 2122  * 
 2123  * The ops are set with release semantics to be certain that the flags, type,
 2124  * and data are visible when ops is.  This is to prevent ops methods from being
 2125  * called with bad data.
 2126  */
 2127 void
 2128 finit(struct file *fp, u_int flag, short type, void *data, struct fileops *ops)
 2129 {
 2130         fp->f_data = data;
 2131         fp->f_flag = flag;
 2132         fp->f_type = type;
 2133         atomic_store_rel_ptr((volatile uintptr_t *)&fp->f_ops, (uintptr_t)ops);
 2134 }
 2135 
 2136 struct file *
 2137 fget_unlocked(struct filedesc *fdp, int fd)
 2138 {
 2139         struct file *fp;
 2140         u_int count;
 2141 
 2142         if (fd < 0 || fd >= fdp->fd_nfiles)
 2143                 return (NULL);
 2144         /*
 2145          * Fetch the descriptor locklessly.  We avoid fdrop() races by
 2146          * never raising a refcount above 0.  To accomplish this we have
 2147          * to use a cmpset loop rather than an atomic_add.  The descriptor
 2148          * must be re-verified once we acquire a reference to be certain
 2149          * that the identity is still correct and we did not lose a race
 2150          * due to preemption.
 2151          */
 2152         for (;;) {
 2153                 fp = fdp->fd_ofiles[fd];
 2154                 if (fp == NULL)
 2155                         break;
 2156                 count = fp->f_count;
 2157                 if (count == 0)
 2158                         continue;
 2159                 /*
 2160                  * Use an acquire barrier to prevent caching of fd_ofiles
 2161                  * so it is refreshed for verification.
 2162                  */
 2163                 if (atomic_cmpset_acq_int(&fp->f_count, count, count + 1) != 1)
 2164                         continue;
 2165                 if (fp == fdp->fd_ofiles[fd])
 2166                         break;
 2167                 fdrop(fp, curthread);
 2168         }
 2169 
 2170         return (fp);
 2171 }
 2172 
 2173 /*
 2174  * Extract the file pointer associated with the specified descriptor for the
 2175  * current user process.
 2176  *
 2177  * If the descriptor doesn't exist or doesn't match 'flags', EBADF is
 2178  * returned.
 2179  *
 2180  * If an error occured the non-zero error is returned and *fpp is set to
 2181  * NULL.  Otherwise *fpp is held and set and zero is returned.  Caller is
 2182  * responsible for fdrop().
 2183  */
 2184 static __inline int
 2185 _fget(struct thread *td, int fd, struct file **fpp, int flags)
 2186 {
 2187         struct filedesc *fdp;
 2188         struct file *fp;
 2189 
 2190         *fpp = NULL;
 2191         if (td == NULL || (fdp = td->td_proc->p_fd) == NULL)
 2192                 return (EBADF);
 2193         if ((fp = fget_unlocked(fdp, fd)) == NULL)
 2194                 return (EBADF);
 2195         if (fp->f_ops == &badfileops) {
 2196                 fdrop(fp, td);
 2197                 return (EBADF);
 2198         }
 2199         /*
 2200          * FREAD and FWRITE failure return EBADF as per POSIX.
 2201          *
 2202          * Only one flag, or 0, may be specified.
 2203          */
 2204         if ((flags == FREAD && (fp->f_flag & FREAD) == 0) ||
 2205             (flags == FWRITE && (fp->f_flag & FWRITE) == 0)) {
 2206                 fdrop(fp, td);
 2207                 return (EBADF);
 2208         }
 2209         *fpp = fp;
 2210         return (0);
 2211 }
 2212 
 2213 int
 2214 fget(struct thread *td, int fd, struct file **fpp)
 2215 {
 2216 
 2217         return(_fget(td, fd, fpp, 0));
 2218 }
 2219 
 2220 int
 2221 fget_read(struct thread *td, int fd, struct file **fpp)
 2222 {
 2223 
 2224         return(_fget(td, fd, fpp, FREAD));
 2225 }
 2226 
 2227 int
 2228 fget_write(struct thread *td, int fd, struct file **fpp)
 2229 {
 2230 
 2231         return(_fget(td, fd, fpp, FWRITE));
 2232 }
 2233 
 2234 /*
 2235  * Like fget() but loads the underlying vnode, or returns an error if the
 2236  * descriptor does not represent a vnode.  Note that pipes use vnodes but
 2237  * never have VM objects.  The returned vnode will be vref()'d.
 2238  *
 2239  * XXX: what about the unused flags ?
 2240  */
 2241 static __inline int
 2242 _fgetvp(struct thread *td, int fd, struct vnode **vpp, int flags)
 2243 {
 2244         struct file *fp;
 2245         int error;
 2246 
 2247         *vpp = NULL;
 2248         if ((error = _fget(td, fd, &fp, flags)) != 0)
 2249                 return (error);
 2250         if (fp->f_vnode == NULL) {
 2251                 error = EINVAL;
 2252         } else {
 2253                 *vpp = fp->f_vnode;
 2254                 vref(*vpp);
 2255         }
 2256         fdrop(fp, td);
 2257 
 2258         return (error);
 2259 }
 2260 
 2261 int
 2262 fgetvp(struct thread *td, int fd, struct vnode **vpp)
 2263 {
 2264 
 2265         return (_fgetvp(td, fd, vpp, 0));
 2266 }
 2267 
 2268 int
 2269 fgetvp_read(struct thread *td, int fd, struct vnode **vpp)
 2270 {
 2271 
 2272         return (_fgetvp(td, fd, vpp, FREAD));
 2273 }
 2274 
 2275 #ifdef notyet
 2276 int
 2277 fgetvp_write(struct thread *td, int fd, struct vnode **vpp)
 2278 {
 2279 
 2280         return (_fgetvp(td, fd, vpp, FWRITE));
 2281 }
 2282 #endif
 2283 
 2284 /*
 2285  * Like fget() but loads the underlying socket, or returns an error if the
 2286  * descriptor does not represent a socket.
 2287  *
 2288  * We bump the ref count on the returned socket.  XXX Also obtain the SX lock
 2289  * in the future.
 2290  *
 2291  * Note: fgetsock() and fputsock() are deprecated, as consumers should rely
 2292  * on their file descriptor reference to prevent the socket from being free'd
 2293  * during use.
 2294  */
 2295 int
 2296 fgetsock(struct thread *td, int fd, struct socket **spp, u_int *fflagp)
 2297 {
 2298         struct file *fp;
 2299         int error;
 2300 
 2301         *spp = NULL;
 2302         if (fflagp != NULL)
 2303                 *fflagp = 0;
 2304         if ((error = _fget(td, fd, &fp, 0)) != 0)
 2305                 return (error);
 2306         if (fp->f_type != DTYPE_SOCKET) {
 2307                 error = ENOTSOCK;
 2308         } else {
 2309                 *spp = fp->f_data;
 2310                 if (fflagp)
 2311                         *fflagp = fp->f_flag;
 2312                 SOCK_LOCK(*spp);
 2313                 soref(*spp);
 2314                 SOCK_UNLOCK(*spp);
 2315         }
 2316         fdrop(fp, td);
 2317 
 2318         return (error);
 2319 }
 2320 
 2321 /*
 2322  * Drop the reference count on the socket and XXX release the SX lock in the
 2323  * future.  The last reference closes the socket.
 2324  *
 2325  * Note: fputsock() is deprecated, see comment for fgetsock().
 2326  */
 2327 void
 2328 fputsock(struct socket *so)
 2329 {
 2330 
 2331         ACCEPT_LOCK();
 2332         SOCK_LOCK(so);
 2333         sorele(so);
 2334 }
 2335 
 2336 /*
 2337  * Handle the last reference to a file being closed.
 2338  */
 2339 int
 2340 _fdrop(struct file *fp, struct thread *td)
 2341 {
 2342         int error;
 2343 
 2344         error = 0;
 2345         if (fp->f_count != 0)
 2346                 panic("fdrop: count %d", fp->f_count);
 2347         if (fp->f_ops != &badfileops)
 2348                 error = fo_close(fp, td);
 2349         /*
 2350          * The f_cdevpriv cannot be assigned non-NULL value while we
 2351          * are destroying the file.
 2352          */
 2353         if (fp->f_cdevpriv != NULL)
 2354                 devfs_fpdrop(fp);
 2355         atomic_subtract_int(&openfiles, 1);
 2356         crfree(fp->f_cred);
 2357         uma_zfree(file_zone, fp);
 2358 
 2359         return (error);
 2360 }
 2361 
 2362 /*
 2363  * Apply an advisory lock on a file descriptor.
 2364  *
 2365  * Just attempt to get a record lock of the requested type on the entire file
 2366  * (l_whence = SEEK_SET, l_start = 0, l_len = 0).
 2367  */
 2368 #ifndef _SYS_SYSPROTO_H_
 2369 struct flock_args {
 2370         int     fd;
 2371         int     how;
 2372 };
 2373 #endif
 2374 /* ARGSUSED */
 2375 int
 2376 flock(struct thread *td, struct flock_args *uap)
 2377 {
 2378         struct file *fp;
 2379         struct vnode *vp;
 2380         struct flock lf;
 2381         int vfslocked;
 2382         int error;
 2383 
 2384         if ((error = fget(td, uap->fd, &fp)) != 0)
 2385                 return (error);
 2386         if (fp->f_type != DTYPE_VNODE) {
 2387                 fdrop(fp, td);
 2388                 return (EOPNOTSUPP);
 2389         }
 2390 
 2391         vp = fp->f_vnode;
 2392         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 2393         lf.l_whence = SEEK_SET;
 2394         lf.l_start = 0;
 2395         lf.l_len = 0;
 2396         if (uap->how & LOCK_UN) {
 2397                 lf.l_type = F_UNLCK;
 2398                 atomic_clear_int(&fp->f_flag, FHASLOCK);
 2399                 error = VOP_ADVLOCK(vp, (caddr_t)fp, F_UNLCK, &lf, F_FLOCK);
 2400                 goto done2;
 2401         }
 2402         if (uap->how & LOCK_EX)
 2403                 lf.l_type = F_WRLCK;
 2404         else if (uap->how & LOCK_SH)
 2405                 lf.l_type = F_RDLCK;
 2406         else {
 2407                 error = EBADF;
 2408                 goto done2;
 2409         }
 2410         atomic_set_int(&fp->f_flag, FHASLOCK);
 2411         error = VOP_ADVLOCK(vp, (caddr_t)fp, F_SETLK, &lf,
 2412             (uap->how & LOCK_NB) ? F_FLOCK : F_FLOCK | F_WAIT);
 2413 done2:
 2414         fdrop(fp, td);
 2415         VFS_UNLOCK_GIANT(vfslocked);
 2416         return (error);
 2417 }
 2418 /*
 2419  * Duplicate the specified descriptor to a free descriptor.
 2420  */
 2421 int
 2422 dupfdopen(struct thread *td, struct filedesc *fdp, int indx, int dfd, int mode, int error)
 2423 {
 2424         struct file *wfp;
 2425         struct file *fp;
 2426 
 2427         /*
 2428          * If the to-be-dup'd fd number is greater than the allowed number
 2429          * of file descriptors, or the fd to be dup'd has already been
 2430          * closed, then reject.
 2431          */
 2432         FILEDESC_XLOCK(fdp);
 2433         if (dfd < 0 || dfd >= fdp->fd_nfiles ||
 2434             (wfp = fdp->fd_ofiles[dfd]) == NULL) {
 2435                 FILEDESC_XUNLOCK(fdp);
 2436                 return (EBADF);
 2437         }
 2438 
 2439         /*
 2440          * There are two cases of interest here.
 2441          *
 2442          * For ENODEV simply dup (dfd) to file descriptor (indx) and return.
 2443          *
 2444          * For ENXIO steal away the file structure from (dfd) and store it in
 2445          * (indx).  (dfd) is effectively closed by this operation.
 2446          *
 2447          * Any other error code is just returned.
 2448          */
 2449         switch (error) {
 2450         case ENODEV:
 2451                 /*
 2452                  * Check that the mode the file is being opened for is a
 2453                  * subset of the mode of the existing descriptor.
 2454                  */
 2455                 if (((mode & (FREAD|FWRITE)) | wfp->f_flag) != wfp->f_flag) {
 2456                         FILEDESC_XUNLOCK(fdp);
 2457                         return (EACCES);
 2458                 }
 2459                 fp = fdp->fd_ofiles[indx];
 2460                 fdp->fd_ofiles[indx] = wfp;
 2461                 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
 2462                 if (fp == NULL)
 2463                         fdused(fdp, indx);
 2464                 fhold(wfp);
 2465                 FILEDESC_XUNLOCK(fdp);
 2466                 if (fp != NULL)
 2467                         /*
 2468                          * We now own the reference to fp that the ofiles[]
 2469                          * array used to own.  Release it.
 2470                          */
 2471                         fdrop(fp, td);
 2472                 return (0);
 2473 
 2474         case ENXIO:
 2475                 /*
 2476                  * Steal away the file pointer from dfd and stuff it into indx.
 2477                  */
 2478                 fp = fdp->fd_ofiles[indx];
 2479                 fdp->fd_ofiles[indx] = fdp->fd_ofiles[dfd];
 2480                 fdp->fd_ofiles[dfd] = NULL;
 2481                 fdp->fd_ofileflags[indx] = fdp->fd_ofileflags[dfd];
 2482                 fdp->fd_ofileflags[dfd] = 0;
 2483                 fdunused(fdp, dfd);
 2484                 if (fp == NULL)
 2485                         fdused(fdp, indx);
 2486                 FILEDESC_XUNLOCK(fdp);
 2487 
 2488                 /*
 2489                  * We now own the reference to fp that the ofiles[] array
 2490                  * used to own.  Release it.
 2491                  */
 2492                 if (fp != NULL)
 2493                         fdrop(fp, td);
 2494                 return (0);
 2495 
 2496         default:
 2497                 FILEDESC_XUNLOCK(fdp);
 2498                 return (error);
 2499         }
 2500         /* NOTREACHED */
 2501 }
 2502 
 2503 /*
 2504  * Scan all active processes and prisons to see if any of them have a current
 2505  * or root directory of `olddp'. If so, replace them with the new mount point.
 2506  */
 2507 void
 2508 mountcheckdirs(struct vnode *olddp, struct vnode *newdp)
 2509 {
 2510         struct filedesc *fdp;
 2511         struct prison *pr;
 2512         struct proc *p;
 2513         int nrele;
 2514 
 2515         if (vrefcnt(olddp) == 1)
 2516                 return;
 2517         nrele = 0;
 2518         sx_slock(&allproc_lock);
 2519         FOREACH_PROC_IN_SYSTEM(p) {
 2520                 fdp = fdhold(p);
 2521                 if (fdp == NULL)
 2522                         continue;
 2523                 FILEDESC_XLOCK(fdp);
 2524                 if (fdp->fd_cdir == olddp) {
 2525                         vref(newdp);
 2526                         fdp->fd_cdir = newdp;
 2527                         nrele++;
 2528                 }
 2529                 if (fdp->fd_rdir == olddp) {
 2530                         vref(newdp);
 2531                         fdp->fd_rdir = newdp;
 2532                         nrele++;
 2533                 }
 2534                 if (fdp->fd_jdir == olddp) {
 2535                         vref(newdp);
 2536                         fdp->fd_jdir = newdp;
 2537                         nrele++;
 2538                 }
 2539                 FILEDESC_XUNLOCK(fdp);
 2540                 fddrop(fdp);
 2541         }
 2542         sx_sunlock(&allproc_lock);
 2543         if (rootvnode == olddp) {
 2544                 vref(newdp);
 2545                 rootvnode = newdp;
 2546                 nrele++;
 2547         }
 2548         mtx_lock(&prison0.pr_mtx);
 2549         if (prison0.pr_root == olddp) {
 2550                 vref(newdp);
 2551                 prison0.pr_root = newdp;
 2552                 nrele++;
 2553         }
 2554         mtx_unlock(&prison0.pr_mtx);
 2555         sx_slock(&allprison_lock);
 2556         TAILQ_FOREACH(pr, &allprison, pr_list) {
 2557                 mtx_lock(&pr->pr_mtx);
 2558                 if (pr->pr_root == olddp) {
 2559                         vref(newdp);
 2560                         pr->pr_root = newdp;
 2561                         nrele++;
 2562                 }
 2563                 mtx_unlock(&pr->pr_mtx);
 2564         }
 2565         sx_sunlock(&allprison_lock);
 2566         while (nrele--)
 2567                 vrele(olddp);
 2568 }
 2569 
 2570 struct filedesc_to_leader *
 2571 filedesc_to_leader_alloc(struct filedesc_to_leader *old, struct filedesc *fdp, struct proc *leader)
 2572 {
 2573         struct filedesc_to_leader *fdtol;
 2574 
 2575         fdtol = malloc(sizeof(struct filedesc_to_leader),
 2576                M_FILEDESC_TO_LEADER,
 2577                M_WAITOK);
 2578         fdtol->fdl_refcount = 1;
 2579         fdtol->fdl_holdcount = 0;
 2580         fdtol->fdl_wakeup = 0;
 2581         fdtol->fdl_leader = leader;
 2582         if (old != NULL) {
 2583                 FILEDESC_XLOCK(fdp);
 2584                 fdtol->fdl_next = old->fdl_next;
 2585                 fdtol->fdl_prev = old;
 2586                 old->fdl_next = fdtol;
 2587                 fdtol->fdl_next->fdl_prev = fdtol;
 2588                 FILEDESC_XUNLOCK(fdp);
 2589         } else {
 2590                 fdtol->fdl_next = fdtol;
 2591                 fdtol->fdl_prev = fdtol;
 2592         }
 2593         return (fdtol);
 2594 }
 2595 
 2596 /*
 2597  * Get file structures globally.
 2598  */
 2599 static int
 2600 sysctl_kern_file(SYSCTL_HANDLER_ARGS)
 2601 {
 2602         struct xfile xf;
 2603         struct filedesc *fdp;
 2604         struct file *fp;
 2605         struct proc *p;
 2606         int error, n;
 2607 
 2608         error = sysctl_wire_old_buffer(req, 0);
 2609         if (error != 0)
 2610                 return (error);
 2611         if (req->oldptr == NULL) {
 2612                 n = 0;
 2613                 sx_slock(&allproc_lock);
 2614                 FOREACH_PROC_IN_SYSTEM(p) {
 2615                         if (p->p_state == PRS_NEW)
 2616                                 continue;
 2617                         fdp = fdhold(p);
 2618                         if (fdp == NULL)
 2619                                 continue;
 2620                         /* overestimates sparse tables. */
 2621                         if (fdp->fd_lastfile > 0)
 2622                                 n += fdp->fd_lastfile;
 2623                         fddrop(fdp);
 2624                 }
 2625                 sx_sunlock(&allproc_lock);
 2626                 return (SYSCTL_OUT(req, 0, n * sizeof(xf)));
 2627         }
 2628         error = 0;
 2629         bzero(&xf, sizeof(xf));
 2630         xf.xf_size = sizeof(xf);
 2631         sx_slock(&allproc_lock);
 2632         FOREACH_PROC_IN_SYSTEM(p) {
 2633                 if (p->p_state == PRS_NEW)
 2634                         continue;
 2635                 PROC_LOCK(p);
 2636                 if (p_cansee(req->td, p) != 0) {
 2637                         PROC_UNLOCK(p);
 2638                         continue;
 2639                 }
 2640                 xf.xf_pid = p->p_pid;
 2641                 xf.xf_uid = p->p_ucred->cr_uid;
 2642                 PROC_UNLOCK(p);
 2643                 fdp = fdhold(p);
 2644                 if (fdp == NULL)
 2645                         continue;
 2646                 FILEDESC_SLOCK(fdp);
 2647                 for (n = 0; fdp->fd_refcnt > 0 && n < fdp->fd_nfiles; ++n) {
 2648                         if ((fp = fdp->fd_ofiles[n]) == NULL)
 2649                                 continue;
 2650                         xf.xf_fd = n;
 2651                         xf.xf_file = fp;
 2652                         xf.xf_data = fp->f_data;
 2653                         xf.xf_vnode = fp->f_vnode;
 2654                         xf.xf_type = fp->f_type;
 2655                         xf.xf_count = fp->f_count;
 2656                         xf.xf_msgcount = 0;
 2657                         xf.xf_offset = fp->f_offset;
 2658                         xf.xf_flag = fp->f_flag;
 2659                         error = SYSCTL_OUT(req, &xf, sizeof(xf));
 2660                         if (error)
 2661                                 break;
 2662                 }
 2663                 FILEDESC_SUNLOCK(fdp);
 2664                 fddrop(fdp);
 2665                 if (error)
 2666                         break;
 2667         }
 2668         sx_sunlock(&allproc_lock);
 2669         return (error);
 2670 }
 2671 
 2672 SYSCTL_PROC(_kern, KERN_FILE, file, CTLTYPE_OPAQUE|CTLFLAG_RD,
 2673     0, 0, sysctl_kern_file, "S,xfile", "Entire file table");
 2674 
 2675 #ifdef KINFO_OFILE_SIZE
 2676 CTASSERT(sizeof(struct kinfo_ofile) == KINFO_OFILE_SIZE);
 2677 #endif
 2678 
 2679 #ifdef COMPAT_FREEBSD7
 2680 static int
 2681 export_vnode_for_osysctl(struct vnode *vp, int type,
 2682     struct kinfo_ofile *kif, struct filedesc *fdp, struct sysctl_req *req)
 2683 {
 2684         int error;
 2685         char *fullpath, *freepath;
 2686         int vfslocked;
 2687 
 2688         bzero(kif, sizeof(*kif));
 2689         kif->kf_structsize = sizeof(*kif);
 2690 
 2691         vref(vp);
 2692         kif->kf_fd = type;
 2693         kif->kf_type = KF_TYPE_VNODE;
 2694         /* This function only handles directories. */
 2695         if (vp->v_type != VDIR) {
 2696                 vrele(vp);
 2697                 return (ENOTDIR);
 2698         }
 2699         kif->kf_vnode_type = KF_VTYPE_VDIR;
 2700 
 2701         /*
 2702          * This is not a true file descriptor, so we set a bogus refcount
 2703          * and offset to indicate these fields should be ignored.
 2704          */
 2705         kif->kf_ref_count = -1;
 2706         kif->kf_offset = -1;
 2707 
 2708         freepath = NULL;
 2709         fullpath = "-";
 2710         FILEDESC_SUNLOCK(fdp);
 2711         vn_fullpath(curthread, vp, &fullpath, &freepath);
 2712         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 2713         vrele(vp);
 2714         VFS_UNLOCK_GIANT(vfslocked);
 2715         strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
 2716         if (freepath != NULL)
 2717                 free(freepath, M_TEMP);
 2718         error = SYSCTL_OUT(req, kif, sizeof(*kif));
 2719         FILEDESC_SLOCK(fdp);
 2720         return (error);
 2721 }
 2722 
 2723 /*
 2724  * Get per-process file descriptors for use by procstat(1), et al.
 2725  */
 2726 static int
 2727 sysctl_kern_proc_ofiledesc(SYSCTL_HANDLER_ARGS)
 2728 {
 2729         char *fullpath, *freepath;
 2730         struct kinfo_ofile *kif;
 2731         struct filedesc *fdp;
 2732         int error, i, *name;
 2733         struct socket *so;
 2734         struct vnode *vp;
 2735         struct file *fp;
 2736         struct proc *p;
 2737         struct tty *tp;
 2738         int vfslocked;
 2739 
 2740         name = (int *)arg1;
 2741         if ((p = pfind((pid_t)name[0])) == NULL)
 2742                 return (ESRCH);
 2743         if ((error = p_candebug(curthread, p))) {
 2744                 PROC_UNLOCK(p);
 2745                 return (error);
 2746         }
 2747         fdp = fdhold(p);
 2748         PROC_UNLOCK(p);
 2749         if (fdp == NULL)
 2750                 return (ENOENT);
 2751         kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK);
 2752         FILEDESC_SLOCK(fdp);
 2753         if (fdp->fd_cdir != NULL)
 2754                 export_vnode_for_osysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif,
 2755                                 fdp, req);
 2756         if (fdp->fd_rdir != NULL)
 2757                 export_vnode_for_osysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif,
 2758                                 fdp, req);
 2759         if (fdp->fd_jdir != NULL)
 2760                 export_vnode_for_osysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif,
 2761                                 fdp, req);
 2762         for (i = 0; i < fdp->fd_nfiles; i++) {
 2763                 if ((fp = fdp->fd_ofiles[i]) == NULL)
 2764                         continue;
 2765                 bzero(kif, sizeof(*kif));
 2766                 kif->kf_structsize = sizeof(*kif);
 2767                 vp = NULL;
 2768                 so = NULL;
 2769                 tp = NULL;
 2770                 kif->kf_fd = i;
 2771                 switch (fp->f_type) {
 2772                 case DTYPE_VNODE:
 2773                         kif->kf_type = KF_TYPE_VNODE;
 2774                         vp = fp->f_vnode;
 2775                         break;
 2776 
 2777                 case DTYPE_SOCKET:
 2778                         kif->kf_type = KF_TYPE_SOCKET;
 2779                         so = fp->f_data;
 2780                         break;
 2781 
 2782                 case DTYPE_PIPE:
 2783                         kif->kf_type = KF_TYPE_PIPE;
 2784                         break;
 2785 
 2786                 case DTYPE_FIFO:
 2787                         kif->kf_type = KF_TYPE_FIFO;
 2788                         vp = fp->f_vnode;
 2789                         break;
 2790 
 2791                 case DTYPE_KQUEUE:
 2792                         kif->kf_type = KF_TYPE_KQUEUE;
 2793                         break;
 2794 
 2795                 case DTYPE_CRYPTO:
 2796                         kif->kf_type = KF_TYPE_CRYPTO;
 2797                         break;
 2798 
 2799                 case DTYPE_MQUEUE:
 2800                         kif->kf_type = KF_TYPE_MQUEUE;
 2801                         break;
 2802 
 2803                 case DTYPE_SHM:
 2804                         kif->kf_type = KF_TYPE_SHM;
 2805                         break;
 2806 
 2807                 case DTYPE_SEM:
 2808                         kif->kf_type = KF_TYPE_SEM;
 2809                         break;
 2810 
 2811                 case DTYPE_PTS:
 2812                         kif->kf_type = KF_TYPE_PTS;
 2813                         tp = fp->f_data;
 2814                         break;
 2815 
 2816                 default:
 2817                         kif->kf_type = KF_TYPE_UNKNOWN;
 2818                         break;
 2819                 }
 2820                 kif->kf_ref_count = fp->f_count;
 2821                 if (fp->f_flag & FREAD)
 2822                         kif->kf_flags |= KF_FLAG_READ;
 2823                 if (fp->f_flag & FWRITE)
 2824                         kif->kf_flags |= KF_FLAG_WRITE;
 2825                 if (fp->f_flag & FAPPEND)
 2826                         kif->kf_flags |= KF_FLAG_APPEND;
 2827                 if (fp->f_flag & FASYNC)
 2828                         kif->kf_flags |= KF_FLAG_ASYNC;
 2829                 if (fp->f_flag & FFSYNC)
 2830                         kif->kf_flags |= KF_FLAG_FSYNC;
 2831                 if (fp->f_flag & FNONBLOCK)
 2832                         kif->kf_flags |= KF_FLAG_NONBLOCK;
 2833                 if (fp->f_flag & O_DIRECT)
 2834                         kif->kf_flags |= KF_FLAG_DIRECT;
 2835                 if (fp->f_flag & FHASLOCK)
 2836                         kif->kf_flags |= KF_FLAG_HASLOCK;
 2837                 kif->kf_offset = fp->f_offset;
 2838                 if (vp != NULL) {
 2839                         vref(vp);
 2840                         switch (vp->v_type) {
 2841                         case VNON:
 2842                                 kif->kf_vnode_type = KF_VTYPE_VNON;
 2843                                 break;
 2844                         case VREG:
 2845                                 kif->kf_vnode_type = KF_VTYPE_VREG;
 2846                                 break;
 2847                         case VDIR:
 2848                                 kif->kf_vnode_type = KF_VTYPE_VDIR;
 2849                                 break;
 2850                         case VBLK:
 2851                                 kif->kf_vnode_type = KF_VTYPE_VBLK;
 2852                                 break;
 2853                         case VCHR:
 2854                                 kif->kf_vnode_type = KF_VTYPE_VCHR;
 2855                                 break;
 2856                         case VLNK:
 2857                                 kif->kf_vnode_type = KF_VTYPE_VLNK;
 2858                                 break;
 2859                         case VSOCK:
 2860                                 kif->kf_vnode_type = KF_VTYPE_VSOCK;
 2861                                 break;
 2862                         case VFIFO:
 2863                                 kif->kf_vnode_type = KF_VTYPE_VFIFO;
 2864                                 break;
 2865                         case VBAD:
 2866                                 kif->kf_vnode_type = KF_VTYPE_VBAD;
 2867                                 break;
 2868                         default:
 2869                                 kif->kf_vnode_type = KF_VTYPE_UNKNOWN;
 2870                                 break;
 2871                         }
 2872                         /*
 2873                          * It is OK to drop the filedesc lock here as we will
 2874                          * re-validate and re-evaluate its properties when
 2875                          * the loop continues.
 2876                          */
 2877                         freepath = NULL;
 2878                         fullpath = "-";
 2879                         FILEDESC_SUNLOCK(fdp);
 2880                         vn_fullpath(curthread, vp, &fullpath, &freepath);
 2881                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 2882                         vrele(vp);
 2883                         VFS_UNLOCK_GIANT(vfslocked);
 2884                         strlcpy(kif->kf_path, fullpath,
 2885                             sizeof(kif->kf_path));
 2886                         if (freepath != NULL)
 2887                                 free(freepath, M_TEMP);
 2888                         FILEDESC_SLOCK(fdp);
 2889                 }
 2890                 if (so != NULL) {
 2891                         struct sockaddr *sa;
 2892 
 2893                         if (so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa)
 2894                             == 0 && sa->sa_len <= sizeof(kif->kf_sa_local)) {
 2895                                 bcopy(sa, &kif->kf_sa_local, sa->sa_len);
 2896                                 free(sa, M_SONAME);
 2897                         }
 2898                         if (so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa)
 2899                             == 0 && sa->sa_len <= sizeof(kif->kf_sa_peer)) {
 2900                                 bcopy(sa, &kif->kf_sa_peer, sa->sa_len);
 2901                                 free(sa, M_SONAME);
 2902                         }
 2903                         kif->kf_sock_domain =
 2904                             so->so_proto->pr_domain->dom_family;
 2905                         kif->kf_sock_type = so->so_type;
 2906                         kif->kf_sock_protocol = so->so_proto->pr_protocol;
 2907                 }
 2908                 if (tp != NULL) {
 2909                         strlcpy(kif->kf_path, tty_devname(tp),
 2910                             sizeof(kif->kf_path));
 2911                 }
 2912                 error = SYSCTL_OUT(req, kif, sizeof(*kif));
 2913                 if (error)
 2914                         break;
 2915         }
 2916         FILEDESC_SUNLOCK(fdp);
 2917         fddrop(fdp);
 2918         free(kif, M_TEMP);
 2919         return (0);
 2920 }
 2921 
 2922 static SYSCTL_NODE(_kern_proc, KERN_PROC_OFILEDESC, ofiledesc, CTLFLAG_RD,
 2923     sysctl_kern_proc_ofiledesc, "Process ofiledesc entries");
 2924 #endif  /* COMPAT_FREEBSD7 */
 2925 
 2926 #ifdef KINFO_FILE_SIZE
 2927 CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE);
 2928 #endif
 2929 
 2930 static int
 2931 export_vnode_for_sysctl(struct vnode *vp, int type,
 2932     struct kinfo_file *kif, struct filedesc *fdp, struct sysctl_req *req)
 2933 {
 2934         int error;
 2935         char *fullpath, *freepath;
 2936         int vfslocked;
 2937 
 2938         bzero(kif, sizeof(*kif));
 2939 
 2940         vref(vp);
 2941         kif->kf_fd = type;
 2942         kif->kf_type = KF_TYPE_VNODE;
 2943         /* This function only handles directories. */
 2944         if (vp->v_type != VDIR) {
 2945                 vrele(vp);
 2946                 return (ENOTDIR);
 2947         }
 2948         kif->kf_vnode_type = KF_VTYPE_VDIR;
 2949 
 2950         /*
 2951          * This is not a true file descriptor, so we set a bogus refcount
 2952          * and offset to indicate these fields should be ignored.
 2953          */
 2954         kif->kf_ref_count = -1;
 2955         kif->kf_offset = -1;
 2956 
 2957         freepath = NULL;
 2958         fullpath = "-";
 2959         FILEDESC_SUNLOCK(fdp);
 2960         vn_fullpath(curthread, vp, &fullpath, &freepath);
 2961         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 2962         vrele(vp);
 2963         VFS_UNLOCK_GIANT(vfslocked);
 2964         strlcpy(kif->kf_path, fullpath, sizeof(kif->kf_path));
 2965         if (freepath != NULL)
 2966                 free(freepath, M_TEMP);
 2967         /* Pack record size down */
 2968         kif->kf_structsize = offsetof(struct kinfo_file, kf_path) +
 2969             strlen(kif->kf_path) + 1;
 2970         kif->kf_structsize = roundup(kif->kf_structsize, sizeof(uint64_t));
 2971         error = SYSCTL_OUT(req, kif, kif->kf_structsize);
 2972         FILEDESC_SLOCK(fdp);
 2973         return (error);
 2974 }
 2975 
 2976 /*
 2977  * Get per-process file descriptors for use by procstat(1), et al.
 2978  */
 2979 static int
 2980 sysctl_kern_proc_filedesc(SYSCTL_HANDLER_ARGS)
 2981 {
 2982         char *fullpath, *freepath;
 2983         struct kinfo_file *kif;
 2984         struct filedesc *fdp;
 2985         int error, i, *name;
 2986         struct socket *so;
 2987         struct vnode *vp;
 2988         struct file *fp;
 2989         struct proc *p;
 2990         struct tty *tp;
 2991         int vfslocked;
 2992         size_t oldidx;
 2993 
 2994         name = (int *)arg1;
 2995         if ((p = pfind((pid_t)name[0])) == NULL)
 2996                 return (ESRCH);
 2997         if ((error = p_candebug(curthread, p))) {
 2998                 PROC_UNLOCK(p);
 2999                 return (error);
 3000         }
 3001         fdp = fdhold(p);
 3002         PROC_UNLOCK(p);
 3003         if (fdp == NULL)
 3004                 return (ENOENT);
 3005         kif = malloc(sizeof(*kif), M_TEMP, M_WAITOK);
 3006         FILEDESC_SLOCK(fdp);
 3007         if (fdp->fd_cdir != NULL)
 3008                 export_vnode_for_sysctl(fdp->fd_cdir, KF_FD_TYPE_CWD, kif,
 3009                                 fdp, req);
 3010         if (fdp->fd_rdir != NULL)
 3011                 export_vnode_for_sysctl(fdp->fd_rdir, KF_FD_TYPE_ROOT, kif,
 3012                                 fdp, req);
 3013         if (fdp->fd_jdir != NULL)
 3014                 export_vnode_for_sysctl(fdp->fd_jdir, KF_FD_TYPE_JAIL, kif,
 3015                                 fdp, req);
 3016         for (i = 0; i < fdp->fd_nfiles; i++) {
 3017                 if ((fp = fdp->fd_ofiles[i]) == NULL)
 3018                         continue;
 3019                 bzero(kif, sizeof(*kif));
 3020                 vp = NULL;
 3021                 so = NULL;
 3022                 tp = NULL;
 3023                 kif->kf_fd = i;
 3024                 switch (fp->f_type) {
 3025                 case DTYPE_VNODE:
 3026                         kif->kf_type = KF_TYPE_VNODE;
 3027                         vp = fp->f_vnode;
 3028                         break;
 3029 
 3030                 case DTYPE_SOCKET:
 3031                         kif->kf_type = KF_TYPE_SOCKET;
 3032                         so = fp->f_data;
 3033                         break;
 3034 
 3035                 case DTYPE_PIPE:
 3036                         kif->kf_type = KF_TYPE_PIPE;
 3037                         break;
 3038 
 3039                 case DTYPE_FIFO:
 3040                         kif->kf_type = KF_TYPE_FIFO;
 3041                         vp = fp->f_vnode;
 3042                         break;
 3043 
 3044                 case DTYPE_KQUEUE:
 3045                         kif->kf_type = KF_TYPE_KQUEUE;
 3046                         break;
 3047 
 3048                 case DTYPE_CRYPTO:
 3049                         kif->kf_type = KF_TYPE_CRYPTO;
 3050                         break;
 3051 
 3052                 case DTYPE_MQUEUE:
 3053                         kif->kf_type = KF_TYPE_MQUEUE;
 3054                         break;
 3055 
 3056                 case DTYPE_SHM:
 3057                         kif->kf_type = KF_TYPE_SHM;
 3058                         break;
 3059 
 3060                 case DTYPE_SEM:
 3061                         kif->kf_type = KF_TYPE_SEM;
 3062                         break;
 3063 
 3064                 case DTYPE_PTS:
 3065                         kif->kf_type = KF_TYPE_PTS;
 3066                         tp = fp->f_data;
 3067                         break;
 3068 
 3069                 default:
 3070                         kif->kf_type = KF_TYPE_UNKNOWN;
 3071                         break;
 3072                 }
 3073                 kif->kf_ref_count = fp->f_count;
 3074                 if (fp->f_flag & FREAD)
 3075                         kif->kf_flags |= KF_FLAG_READ;
 3076                 if (fp->f_flag & FWRITE)
 3077                         kif->kf_flags |= KF_FLAG_WRITE;
 3078                 if (fp->f_flag & FAPPEND)
 3079                         kif->kf_flags |= KF_FLAG_APPEND;
 3080                 if (fp->f_flag & FASYNC)
 3081                         kif->kf_flags |= KF_FLAG_ASYNC;
 3082                 if (fp->f_flag & FFSYNC)
 3083                         kif->kf_flags |= KF_FLAG_FSYNC;
 3084                 if (fp->f_flag & FNONBLOCK)
 3085                         kif->kf_flags |= KF_FLAG_NONBLOCK;
 3086                 if (fp->f_flag & O_DIRECT)
 3087                         kif->kf_flags |= KF_FLAG_DIRECT;
 3088                 if (fp->f_flag & FHASLOCK)
 3089                         kif->kf_flags |= KF_FLAG_HASLOCK;
 3090                 kif->kf_offset = fp->f_offset;
 3091                 if (vp != NULL) {
 3092                         vref(vp);
 3093                         switch (vp->v_type) {
 3094                         case VNON:
 3095                                 kif->kf_vnode_type = KF_VTYPE_VNON;
 3096                                 break;
 3097                         case VREG:
 3098                                 kif->kf_vnode_type = KF_VTYPE_VREG;
 3099                                 break;
 3100                         case VDIR:
 3101                                 kif->kf_vnode_type = KF_VTYPE_VDIR;
 3102                                 break;
 3103                         case VBLK:
 3104                                 kif->kf_vnode_type = KF_VTYPE_VBLK;
 3105                                 break;
 3106                         case VCHR:
 3107                                 kif->kf_vnode_type = KF_VTYPE_VCHR;
 3108                                 break;
 3109                         case VLNK:
 3110                                 kif->kf_vnode_type = KF_VTYPE_VLNK;
 3111                                 break;
 3112                         case VSOCK:
 3113                                 kif->kf_vnode_type = KF_VTYPE_VSOCK;
 3114                                 break;
 3115                         case VFIFO:
 3116                                 kif->kf_vnode_type = KF_VTYPE_VFIFO;
 3117                                 break;
 3118                         case VBAD:
 3119                                 kif->kf_vnode_type = KF_VTYPE_VBAD;
 3120                                 break;
 3121                         default:
 3122                                 kif->kf_vnode_type = KF_VTYPE_UNKNOWN;
 3123                                 break;
 3124                         }
 3125                         /*
 3126                          * It is OK to drop the filedesc lock here as we will
 3127                          * re-validate and re-evaluate its properties when
 3128                          * the loop continues.
 3129                          */
 3130                         freepath = NULL;
 3131                         fullpath = "-";
 3132                         FILEDESC_SUNLOCK(fdp);
 3133                         vn_fullpath(curthread, vp, &fullpath, &freepath);
 3134                         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 3135                         vrele(vp);
 3136                         VFS_UNLOCK_GIANT(vfslocked);
 3137                         strlcpy(kif->kf_path, fullpath,
 3138                             sizeof(kif->kf_path));
 3139                         if (freepath != NULL)
 3140                                 free(freepath, M_TEMP);
 3141                         FILEDESC_SLOCK(fdp);
 3142                 }
 3143                 if (so != NULL) {
 3144                         struct sockaddr *sa;
 3145 
 3146                         if (so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa)
 3147                             == 0 && sa->sa_len <= sizeof(kif->kf_sa_local)) {
 3148                                 bcopy(sa, &kif->kf_sa_local, sa->sa_len);
 3149                                 free(sa, M_SONAME);
 3150                         }
 3151                         if (so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa)
 3152                             == 0 && sa->sa_len <= sizeof(kif->kf_sa_peer)) {
 3153                                 bcopy(sa, &kif->kf_sa_peer, sa->sa_len);
 3154                                 free(sa, M_SONAME);
 3155                         }
 3156                         kif->kf_sock_domain =
 3157                             so->so_proto->pr_domain->dom_family;
 3158                         kif->kf_sock_type = so->so_type;
 3159                         kif->kf_sock_protocol = so->so_proto->pr_protocol;
 3160                 }
 3161                 if (tp != NULL) {
 3162                         strlcpy(kif->kf_path, tty_devname(tp),
 3163                             sizeof(kif->kf_path));
 3164                 }
 3165                 /* Pack record size down */
 3166                 kif->kf_structsize = offsetof(struct kinfo_file, kf_path) +
 3167                     strlen(kif->kf_path) + 1;
 3168                 kif->kf_structsize = roundup(kif->kf_structsize,
 3169                     sizeof(uint64_t));
 3170                 oldidx = req->oldidx;
 3171                 error = SYSCTL_OUT(req, kif, kif->kf_structsize);
 3172                 if (error) {
 3173                         if (error == ENOMEM) {
 3174                                 /*
 3175                                  * The hack to keep the ABI of sysctl
 3176                                  * kern.proc.filedesc intact, but not
 3177                                  * to account a partially copied
 3178                                  * kinfo_file into the oldidx.
 3179                                  */
 3180                                 req->oldidx = oldidx;
 3181                                 error = 0;
 3182                         }
 3183                         break;
 3184                 }
 3185         }
 3186         FILEDESC_SUNLOCK(fdp);
 3187         fddrop(fdp);
 3188         free(kif, M_TEMP);
 3189         return (error);
 3190 }
 3191 
 3192 static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, CTLFLAG_RD,
 3193     sysctl_kern_proc_filedesc, "Process filedesc entries");
 3194 
 3195 #ifdef DDB
 3196 /*
 3197  * For the purposes of debugging, generate a human-readable string for the
 3198  * file type.
 3199  */
 3200 static const char *
 3201 file_type_to_name(short type)
 3202 {
 3203 
 3204         switch (type) {
 3205         case 0:
 3206                 return ("zero");
 3207         case DTYPE_VNODE:
 3208                 return ("vnod");
 3209         case DTYPE_SOCKET:
 3210                 return ("sock");
 3211         case DTYPE_PIPE:
 3212                 return ("pipe");
 3213         case DTYPE_FIFO:
 3214                 return ("fifo");
 3215         case DTYPE_KQUEUE:
 3216                 return ("kque");
 3217         case DTYPE_CRYPTO:
 3218                 return ("crpt");
 3219         case DTYPE_MQUEUE:
 3220                 return ("mque");
 3221         case DTYPE_SHM:
 3222                 return ("shm");
 3223         case DTYPE_SEM:
 3224                 return ("ksem");
 3225         default:
 3226                 return ("unkn");
 3227         }
 3228 }
 3229 
 3230 /*
 3231  * For the purposes of debugging, identify a process (if any, perhaps one of
 3232  * many) that references the passed file in its file descriptor array. Return
 3233  * NULL if none.
 3234  */
 3235 static struct proc *
 3236 file_to_first_proc(struct file *fp)
 3237 {
 3238         struct filedesc *fdp;
 3239         struct proc *p;
 3240         int n;
 3241 
 3242         FOREACH_PROC_IN_SYSTEM(p) {
 3243                 if (p->p_state == PRS_NEW)
 3244                         continue;
 3245                 fdp = p->p_fd;
 3246                 if (fdp == NULL)
 3247                         continue;
 3248                 for (n = 0; n < fdp->fd_nfiles; n++) {
 3249                         if (fp == fdp->fd_ofiles[n])
 3250                                 return (p);
 3251                 }
 3252         }
 3253         return (NULL);
 3254 }
 3255 
 3256 static void
 3257 db_print_file(struct file *fp, int header)
 3258 {
 3259         struct proc *p;
 3260 
 3261         if (header)
 3262                 db_printf("%8s %4s %8s %8s %4s %5s %6s %8s %5s %12s\n",
 3263                     "File", "Type", "Data", "Flag", "GCFl", "Count",
 3264                     "MCount", "Vnode", "FPID", "FCmd");
 3265         p = file_to_first_proc(fp);
 3266         db_printf("%8p %4s %8p %08x %04x %5d %6d %8p %5d %12s\n", fp,
 3267             file_type_to_name(fp->f_type), fp->f_data, fp->f_flag,
 3268             0, fp->f_count, 0, fp->f_vnode,
 3269             p != NULL ? p->p_pid : -1, p != NULL ? p->p_comm : "-");
 3270 }
 3271 
 3272 DB_SHOW_COMMAND(file, db_show_file)
 3273 {
 3274         struct file *fp;
 3275 
 3276         if (!have_addr) {
 3277                 db_printf("usage: show file <addr>\n");
 3278                 return;
 3279         }
 3280         fp = (struct file *)addr;
 3281         db_print_file(fp, 1);
 3282 }
 3283 
 3284 DB_SHOW_COMMAND(files, db_show_files)
 3285 {
 3286         struct filedesc *fdp;
 3287         struct file *fp;
 3288         struct proc *p;
 3289         int header;
 3290         int n;
 3291 
 3292         header = 1;
 3293         FOREACH_PROC_IN_SYSTEM(p) {
 3294                 if (p->p_state == PRS_NEW)
 3295                         continue;
 3296                 if ((fdp = p->p_fd) == NULL)
 3297                         continue;
 3298                 for (n = 0; n < fdp->fd_nfiles; ++n) {
 3299                         if ((fp = fdp->fd_ofiles[n]) == NULL)
 3300                                 continue;
 3301                         db_print_file(fp, header);
 3302                         header = 0;
 3303                 }
 3304         }
 3305 }
 3306 #endif
 3307 
 3308 SYSCTL_INT(_kern, KERN_MAXFILESPERPROC, maxfilesperproc, CTLFLAG_RW,
 3309     &maxfilesperproc, 0, "Maximum files allowed open per process");
 3310 
 3311 SYSCTL_INT(_kern, KERN_MAXFILES, maxfiles, CTLFLAG_RW,
 3312     &maxfiles, 0, "Maximum number of files");
 3313 
 3314 SYSCTL_INT(_kern, OID_AUTO, openfiles, CTLFLAG_RD,
 3315     __DEVOLATILE(int *, &openfiles), 0, "System-wide number of open files");
 3316 
 3317 /* ARGSUSED*/
 3318 static void
 3319 filelistinit(void *dummy)
 3320 {
 3321 
 3322         file_zone = uma_zcreate("Files", sizeof(struct file), NULL, NULL,
 3323             NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
 3324         mtx_init(&sigio_lock, "sigio lock", NULL, MTX_DEF);
 3325         mtx_init(&fdesc_mtx, "fdesc", NULL, MTX_DEF);
 3326 }
 3327 SYSINIT(select, SI_SUB_LOCK, SI_ORDER_FIRST, filelistinit, NULL);
 3328 
 3329 /*-------------------------------------------------------------------*/
 3330 
 3331 static int
 3332 badfo_readwrite(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td)
 3333 {
 3334 
 3335         return (EBADF);
 3336 }
 3337 
 3338 static int
 3339 badfo_truncate(struct file *fp, off_t length, struct ucred *active_cred, struct thread *td)
 3340 {
 3341 
 3342         return (EINVAL);
 3343 }
 3344 
 3345 static int
 3346 badfo_ioctl(struct file *fp, u_long com, void *data, struct ucred *active_cred, struct thread *td)
 3347 {
 3348 
 3349         return (EBADF);
 3350 }
 3351 
 3352 static int
 3353 badfo_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td)
 3354 {
 3355 
 3356         return (0);
 3357 }
 3358 
 3359 static int
 3360 badfo_kqfilter(struct file *fp, struct knote *kn)
 3361 {
 3362 
 3363         return (EBADF);
 3364 }
 3365 
 3366 static int
 3367 badfo_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, struct thread *td)
 3368 {
 3369 
 3370         return (EBADF);
 3371 }
 3372 
 3373 static int
 3374 badfo_close(struct file *fp, struct thread *td)
 3375 {
 3376 
 3377         return (EBADF);
 3378 }
 3379 
 3380 struct fileops badfileops = {
 3381         .fo_read = badfo_readwrite,
 3382         .fo_write = badfo_readwrite,
 3383         .fo_truncate = badfo_truncate,
 3384         .fo_ioctl = badfo_ioctl,
 3385         .fo_poll = badfo_poll,
 3386         .fo_kqfilter = badfo_kqfilter,
 3387         .fo_stat = badfo_stat,
 3388         .fo_close = badfo_close,
 3389 };
 3390 
 3391 
 3392 /*-------------------------------------------------------------------*/
 3393 
 3394 /*
 3395  * File Descriptor pseudo-device driver (/dev/fd/).
 3396  *
 3397  * Opening minor device N dup()s the file (if any) connected to file
 3398  * descriptor N belonging to the calling process.  Note that this driver
 3399  * consists of only the ``open()'' routine, because all subsequent
 3400  * references to this file will be direct to the other driver.
 3401  *
 3402  * XXX: we could give this one a cloning event handler if necessary.
 3403  */
 3404 
 3405 /* ARGSUSED */
 3406 static int
 3407 fdopen(struct cdev *dev, int mode, int type, struct thread *td)
 3408 {
 3409 
 3410         /*
 3411          * XXX Kludge: set curthread->td_dupfd to contain the value of the
 3412          * the file descriptor being sought for duplication. The error
 3413          * return ensures that the vnode for this device will be released
 3414          * by vn_open. Open will detect this special error and take the
 3415          * actions in dupfdopen below. Other callers of vn_open or VOP_OPEN
 3416          * will simply report the error.
 3417          */
 3418         td->td_dupfd = dev2unit(dev);
 3419         return (ENODEV);
 3420 }
 3421 
 3422 static struct cdevsw fildesc_cdevsw = {
 3423         .d_version =    D_VERSION,
 3424         .d_open =       fdopen,
 3425         .d_name =       "FD",
 3426 };
 3427 
 3428 static void
 3429 fildesc_drvinit(void *unused)
 3430 {
 3431         struct cdev *dev;
 3432 
 3433         dev = make_dev(&fildesc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0666, "fd/0");
 3434         make_dev_alias(dev, "stdin");
 3435         dev = make_dev(&fildesc_cdevsw, 1, UID_ROOT, GID_WHEEL, 0666, "fd/1");
 3436         make_dev_alias(dev, "stdout");
 3437         dev = make_dev(&fildesc_cdevsw, 2, UID_ROOT, GID_WHEEL, 0666, "fd/2");
 3438         make_dev_alias(dev, "stderr");
 3439 }
 3440 
 3441 SYSINIT(fildescdev, SI_SUB_DRIVERS, SI_ORDER_MIDDLE, fildesc_drvinit, NULL);

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