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

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    1 /*      $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $      */
    2 /*-
    3  * Copyright (c) 1994 Adam Glass and Charles Hannum.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 3. All advertising materials mentioning features or use of this software
   14  *    must display the following acknowledgement:
   15  *      This product includes software developed by Adam Glass and Charles
   16  *      Hannum.
   17  * 4. The names of the authors may not be used to endorse or promote products
   18  *    derived from this software without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
   21  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   22  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   23  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   25  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   29  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   30  */
   31 /*-
   32  * Copyright (c) 2003-2005 McAfee, Inc.
   33  * All rights reserved.
   34  *
   35  * This software was developed for the FreeBSD Project in part by McAfee
   36  * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
   37  * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
   38  * program.
   39  *
   40  * Redistribution and use in source and binary forms, with or without
   41  * modification, are permitted provided that the following conditions
   42  * are met:
   43  * 1. Redistributions of source code must retain the above copyright
   44  *    notice, this list of conditions and the following disclaimer.
   45  * 2. Redistributions in binary form must reproduce the above copyright
   46  *    notice, this list of conditions and the following disclaimer in the
   47  *    documentation and/or other materials provided with the distribution.
   48  *
   49  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   59  * SUCH DAMAGE.
   60  */
   61 
   62 #include <sys/cdefs.h>
   63 __FBSDID("$FreeBSD: src/sys/kern/sysv_shm.c,v 1.102 2005/05/12 20:04:48 jhb Exp $");
   64 
   65 #include "opt_compat.h"
   66 #include "opt_sysvipc.h"
   67 #include "opt_mac.h"
   68 
   69 #include <sys/param.h>
   70 #include <sys/systm.h>
   71 #include <sys/kernel.h>
   72 #include <sys/lock.h>
   73 #include <sys/sysctl.h>
   74 #include <sys/shm.h>
   75 #include <sys/proc.h>
   76 #include <sys/malloc.h>
   77 #include <sys/mman.h>
   78 #include <sys/module.h>
   79 #include <sys/mutex.h>
   80 #include <sys/resourcevar.h>
   81 #include <sys/stat.h>
   82 #include <sys/syscall.h>
   83 #include <sys/syscallsubr.h>
   84 #include <sys/sysent.h>
   85 #include <sys/sysproto.h>
   86 #include <sys/jail.h>
   87 #include <sys/mac.h>
   88 
   89 #include <vm/vm.h>
   90 #include <vm/vm_param.h>
   91 #include <vm/pmap.h>
   92 #include <vm/vm_object.h>
   93 #include <vm/vm_map.h>
   94 #include <vm/vm_page.h>
   95 #include <vm/vm_pager.h>
   96 
   97 #ifdef MAC_DEBUG
   98 #define MPRINTF(a)      printf a
   99 #else
  100 #define MPRINTF(a)      
  101 #endif
  102 
  103 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
  104 
  105 struct oshmctl_args;
  106 static int oshmctl(struct thread *td, struct oshmctl_args *uap);
  107 
  108 static int shmget_allocate_segment(struct thread *td,
  109     struct shmget_args *uap, int mode);
  110 static int shmget_existing(struct thread *td, struct shmget_args *uap,
  111     int mode, int segnum);
  112 
  113 /* XXX casting to (sy_call_t *) is bogus, as usual. */
  114 static sy_call_t *shmcalls[] = {
  115         (sy_call_t *)shmat, (sy_call_t *)oshmctl,
  116         (sy_call_t *)shmdt, (sy_call_t *)shmget,
  117         (sy_call_t *)shmctl
  118 };
  119 
  120 #define SHMSEG_FREE             0x0200
  121 #define SHMSEG_REMOVED          0x0400
  122 #define SHMSEG_ALLOCATED        0x0800
  123 #define SHMSEG_WANTED           0x1000
  124 
  125 static int shm_last_free, shm_nused, shm_committed, shmalloced;
  126 static struct shmid_kernel      *shmsegs;
  127 
  128 struct shmmap_state {
  129         vm_offset_t va;
  130         int shmid;
  131 };
  132 
  133 static void shm_deallocate_segment(struct shmid_kernel *);
  134 static int shm_find_segment_by_key(key_t);
  135 static struct shmid_kernel *shm_find_segment_by_shmid(int);
  136 static struct shmid_kernel *shm_find_segment_by_shmidx(int);
  137 static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
  138 static void shmrealloc(void);
  139 static void shminit(void);
  140 static int sysvshm_modload(struct module *, int, void *);
  141 static int shmunload(void);
  142 static void shmexit_myhook(struct vmspace *vm);
  143 static void shmfork_myhook(struct proc *p1, struct proc *p2);
  144 static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
  145 
  146 /*
  147  * Tuneable values.
  148  */
  149 #ifndef SHMMAXPGS
  150 #define SHMMAXPGS       8192    /* Note: sysv shared memory is swap backed. */
  151 #endif
  152 #ifndef SHMMAX
  153 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
  154 #endif
  155 #ifndef SHMMIN
  156 #define SHMMIN  1
  157 #endif
  158 #ifndef SHMMNI
  159 #define SHMMNI  192
  160 #endif
  161 #ifndef SHMSEG
  162 #define SHMSEG  128
  163 #endif
  164 #ifndef SHMALL
  165 #define SHMALL  (SHMMAXPGS)
  166 #endif
  167 
  168 struct  shminfo shminfo = {
  169         SHMMAX,
  170         SHMMIN,
  171         SHMMNI,
  172         SHMSEG,
  173         SHMALL
  174 };
  175 
  176 static int shm_use_phys;
  177 static int shm_allow_removed;
  178 
  179 SYSCTL_DECL(_kern_ipc);
  180 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
  181     "Maximum shared memory segment size");
  182 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
  183     "Minimum shared memory segment size");
  184 SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0,
  185     "Number of shared memory identifiers");
  186 SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0,
  187     "Number of segments per process");
  188 SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
  189     "Maximum number of pages available for shared memory");
  190 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
  191     &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
  192 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
  193     &shm_allow_removed, 0,
  194     "Enable/Disable attachment to attached segments marked for removal");
  195 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD,
  196     NULL, 0, sysctl_shmsegs, "",
  197     "Current number of shared memory segments allocated");
  198 
  199 static int
  200 shm_find_segment_by_key(key)
  201         key_t key;
  202 {
  203         int i;
  204 
  205         for (i = 0; i < shmalloced; i++)
  206                 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) &&
  207                     shmsegs[i].u.shm_perm.key == key)
  208                         return (i);
  209         return (-1);
  210 }
  211 
  212 static struct shmid_kernel *
  213 shm_find_segment_by_shmid(int shmid)
  214 {
  215         int segnum;
  216         struct shmid_kernel *shmseg;
  217 
  218         segnum = IPCID_TO_IX(shmid);
  219         if (segnum < 0 || segnum >= shmalloced)
  220                 return (NULL);
  221         shmseg = &shmsegs[segnum];
  222         if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
  223             (!shm_allow_removed &&
  224              (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) ||
  225             shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid))
  226                 return (NULL);
  227         return (shmseg);
  228 }
  229 
  230 static struct shmid_kernel *
  231 shm_find_segment_by_shmidx(int segnum)
  232 {
  233         struct shmid_kernel *shmseg;
  234 
  235         if (segnum < 0 || segnum >= shmalloced)
  236                 return (NULL);
  237         shmseg = &shmsegs[segnum];
  238         if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
  239             (!shm_allow_removed &&
  240              (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0))
  241                 return (NULL);
  242         return (shmseg);
  243 }
  244 
  245 static void
  246 shm_deallocate_segment(shmseg)
  247         struct shmid_kernel *shmseg;
  248 {
  249         size_t size;
  250 
  251         GIANT_REQUIRED;
  252 
  253         vm_object_deallocate(shmseg->u.shm_internal);
  254         shmseg->u.shm_internal = NULL;
  255         size = round_page(shmseg->u.shm_segsz);
  256         shm_committed -= btoc(size);
  257         shm_nused--;
  258         shmseg->u.shm_perm.mode = SHMSEG_FREE;
  259 #ifdef MAC
  260         mac_cleanup_sysv_shm(shmseg);
  261 #endif
  262 }
  263 
  264 static int
  265 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
  266 {
  267         struct shmid_kernel *shmseg;
  268         int segnum, result;
  269         size_t size;
  270 
  271         GIANT_REQUIRED;
  272 
  273         segnum = IPCID_TO_IX(shmmap_s->shmid);
  274         shmseg = &shmsegs[segnum];
  275         size = round_page(shmseg->u.shm_segsz);
  276         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
  277         if (result != KERN_SUCCESS)
  278                 return (EINVAL);
  279         shmmap_s->shmid = -1;
  280         shmseg->u.shm_dtime = time_second;
  281         if ((--shmseg->u.shm_nattch <= 0) &&
  282             (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) {
  283                 shm_deallocate_segment(shmseg);
  284                 shm_last_free = segnum;
  285         }
  286         return (0);
  287 }
  288 
  289 #ifndef _SYS_SYSPROTO_H_
  290 struct shmdt_args {
  291         const void *shmaddr;
  292 };
  293 #endif
  294 
  295 /*
  296  * MPSAFE
  297  */
  298 int
  299 shmdt(td, uap)
  300         struct thread *td;
  301         struct shmdt_args *uap;
  302 {
  303         struct proc *p = td->td_proc;
  304         struct shmmap_state *shmmap_s;
  305 #ifdef MAC
  306         struct shmid_kernel *shmsegptr;
  307 #endif
  308         int i;
  309         int error = 0;
  310 
  311         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
  312                 return (ENOSYS);
  313         mtx_lock(&Giant);
  314         shmmap_s = p->p_vmspace->vm_shm;
  315         if (shmmap_s == NULL) {
  316                 error = EINVAL;
  317                 goto done2;
  318         }
  319         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
  320                 if (shmmap_s->shmid != -1 &&
  321                     shmmap_s->va == (vm_offset_t)uap->shmaddr) {
  322                         break;
  323                 }
  324         }
  325         if (i == shminfo.shmseg) {
  326                 error = EINVAL;
  327                 goto done2;
  328         }
  329 #ifdef MAC
  330         shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)];
  331         error = mac_check_sysv_shmdt(td->td_ucred, shmsegptr);
  332         if (error != 0) {
  333                 MPRINTF(("mac_check_sysv_shmdt returned %d\n", error));
  334                 goto done2;
  335         }
  336 #endif
  337         error = shm_delete_mapping(p->p_vmspace, shmmap_s);
  338 done2:
  339         mtx_unlock(&Giant);
  340         return (error);
  341 }
  342 
  343 #ifndef _SYS_SYSPROTO_H_
  344 struct shmat_args {
  345         int shmid;
  346         const void *shmaddr;
  347         int shmflg;
  348 };
  349 #endif
  350 
  351 /*
  352  * MPSAFE
  353  */
  354 int
  355 kern_shmat(td, shmid, shmaddr, shmflg)
  356         struct thread *td;
  357         int shmid;
  358         const void *shmaddr;
  359         int shmflg;
  360 {
  361         struct proc *p = td->td_proc;
  362         int i, flags;
  363         struct shmid_kernel *shmseg;
  364         struct shmmap_state *shmmap_s = NULL;
  365         vm_offset_t attach_va;
  366         vm_prot_t prot;
  367         vm_size_t size;
  368         int rv;
  369         int error = 0;
  370 
  371         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
  372                 return (ENOSYS);
  373         mtx_lock(&Giant);
  374         shmmap_s = p->p_vmspace->vm_shm;
  375         if (shmmap_s == NULL) {
  376                 size = shminfo.shmseg * sizeof(struct shmmap_state);
  377                 shmmap_s = malloc(size, M_SHM, M_WAITOK);
  378                 for (i = 0; i < shminfo.shmseg; i++)
  379                         shmmap_s[i].shmid = -1;
  380                 p->p_vmspace->vm_shm = shmmap_s;
  381         }
  382         shmseg = shm_find_segment_by_shmid(shmid);
  383         if (shmseg == NULL) {
  384                 error = EINVAL;
  385                 goto done2;
  386         }
  387         error = ipcperm(td, &shmseg->u.shm_perm,
  388             (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
  389         if (error)
  390                 goto done2;
  391 #ifdef MAC
  392         error = mac_check_sysv_shmat(td->td_ucred, shmseg, shmflg);
  393         if (error != 0) {
  394                 MPRINTF(("mac_check_sysv_shmat returned %d\n", error));
  395                 goto done2;
  396         }
  397 #endif
  398         for (i = 0; i < shminfo.shmseg; i++) {
  399                 if (shmmap_s->shmid == -1)
  400                         break;
  401                 shmmap_s++;
  402         }
  403         if (i >= shminfo.shmseg) {
  404                 error = EMFILE;
  405                 goto done2;
  406         }
  407         size = round_page(shmseg->u.shm_segsz);
  408 #ifdef VM_PROT_READ_IS_EXEC
  409         prot = VM_PROT_READ | VM_PROT_EXECUTE;
  410 #else
  411         prot = VM_PROT_READ;
  412 #endif
  413         if ((shmflg & SHM_RDONLY) == 0)
  414                 prot |= VM_PROT_WRITE;
  415         flags = MAP_ANON | MAP_SHARED;
  416         if (shmaddr) {
  417                 flags |= MAP_FIXED;
  418                 if (shmflg & SHM_RND) {
  419                         attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
  420                 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
  421                         attach_va = (vm_offset_t)shmaddr;
  422                 } else {
  423                         error = EINVAL;
  424                         goto done2;
  425                 }
  426         } else {
  427                 /*
  428                  * This is just a hint to vm_map_find() about where to
  429                  * put it.
  430                  */
  431                 PROC_LOCK(p);
  432                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
  433                     lim_max(p, RLIMIT_DATA));
  434                 PROC_UNLOCK(p);
  435         }
  436 
  437         vm_object_reference(shmseg->u.shm_internal);
  438         rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->u.shm_internal,
  439                 0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
  440         if (rv != KERN_SUCCESS) {
  441                 vm_object_deallocate(shmseg->u.shm_internal);
  442                 error = ENOMEM;
  443                 goto done2;
  444         }
  445         vm_map_inherit(&p->p_vmspace->vm_map,
  446                 attach_va, attach_va + size, VM_INHERIT_SHARE);
  447 
  448         shmmap_s->va = attach_va;
  449         shmmap_s->shmid = shmid;
  450         shmseg->u.shm_lpid = p->p_pid;
  451         shmseg->u.shm_atime = time_second;
  452         shmseg->u.shm_nattch++;
  453         td->td_retval[0] = attach_va;
  454 done2:
  455         mtx_unlock(&Giant);
  456         return (error);
  457 }
  458 
  459 int
  460 shmat(td, uap)
  461         struct thread *td;
  462         struct shmat_args *uap;
  463 {
  464         return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg);
  465 }
  466 
  467 struct oshmid_ds {
  468         struct  ipc_perm shm_perm;      /* operation perms */
  469         int     shm_segsz;              /* size of segment (bytes) */
  470         u_short shm_cpid;               /* pid, creator */
  471         u_short shm_lpid;               /* pid, last operation */
  472         short   shm_nattch;             /* no. of current attaches */
  473         time_t  shm_atime;              /* last attach time */
  474         time_t  shm_dtime;              /* last detach time */
  475         time_t  shm_ctime;              /* last change time */
  476         void    *shm_handle;            /* internal handle for shm segment */
  477 };
  478 
  479 struct oshmctl_args {
  480         int shmid;
  481         int cmd;
  482         struct oshmid_ds *ubuf;
  483 };
  484 
  485 /*
  486  * MPSAFE
  487  */
  488 static int
  489 oshmctl(td, uap)
  490         struct thread *td;
  491         struct oshmctl_args *uap;
  492 {
  493 #ifdef COMPAT_43
  494         int error = 0;
  495         struct shmid_kernel *shmseg;
  496         struct oshmid_ds outbuf;
  497 
  498         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
  499                 return (ENOSYS);
  500         mtx_lock(&Giant);
  501         shmseg = shm_find_segment_by_shmid(uap->shmid);
  502         if (shmseg == NULL) {
  503                 error = EINVAL;
  504                 goto done2;
  505         }
  506         switch (uap->cmd) {
  507         case IPC_STAT:
  508                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
  509                 if (error)
  510                         goto done2;
  511 #ifdef MAC
  512                 error = mac_check_sysv_shmctl(td->td_ucred, shmseg, uap->cmd);
  513                 if (error != 0) {
  514                         MPRINTF(("mac_check_sysv_shmctl returned %d\n",
  515                             error));
  516                         goto done2;
  517                 }
  518 #endif
  519                 outbuf.shm_perm = shmseg->u.shm_perm;
  520                 outbuf.shm_segsz = shmseg->u.shm_segsz;
  521                 outbuf.shm_cpid = shmseg->u.shm_cpid;
  522                 outbuf.shm_lpid = shmseg->u.shm_lpid;
  523                 outbuf.shm_nattch = shmseg->u.shm_nattch;
  524                 outbuf.shm_atime = shmseg->u.shm_atime;
  525                 outbuf.shm_dtime = shmseg->u.shm_dtime;
  526                 outbuf.shm_ctime = shmseg->u.shm_ctime;
  527                 outbuf.shm_handle = shmseg->u.shm_internal;
  528                 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
  529                 if (error)
  530                         goto done2;
  531                 break;
  532         default:
  533                 error = shmctl(td, (struct shmctl_args *)uap);
  534                 break;
  535         }
  536 done2:
  537         mtx_unlock(&Giant);
  538         return (error);
  539 #else
  540         return (EINVAL);
  541 #endif
  542 }
  543 
  544 #ifndef _SYS_SYSPROTO_H_
  545 struct shmctl_args {
  546         int shmid;
  547         int cmd;
  548         struct shmid_ds *buf;
  549 };
  550 #endif
  551 
  552 /*
  553  * MPSAFE
  554  */
  555 int
  556 kern_shmctl(td, shmid, cmd, buf, bufsz)
  557         struct thread *td;
  558         int shmid;
  559         int cmd;
  560         void *buf;
  561         size_t *bufsz;
  562 {
  563         int error = 0;
  564         struct shmid_kernel *shmseg;
  565 
  566         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
  567                 return (ENOSYS);
  568 
  569         mtx_lock(&Giant);
  570         switch (cmd) {
  571         case IPC_INFO:
  572                 memcpy(buf, &shminfo, sizeof(shminfo));
  573                 if (bufsz)
  574                         *bufsz = sizeof(shminfo);
  575                 td->td_retval[0] = shmalloced;
  576                 goto done2;
  577         case SHM_INFO: {
  578                 struct shm_info shm_info;
  579                 shm_info.used_ids = shm_nused;
  580                 shm_info.shm_rss = 0;   /*XXX where to get from ? */
  581                 shm_info.shm_tot = 0;   /*XXX where to get from ? */
  582                 shm_info.shm_swp = 0;   /*XXX where to get from ? */
  583                 shm_info.swap_attempts = 0;     /*XXX where to get from ? */
  584                 shm_info.swap_successes = 0;    /*XXX where to get from ? */
  585                 memcpy(buf, &shm_info, sizeof(shm_info));
  586                 if (bufsz)
  587                         *bufsz = sizeof(shm_info);
  588                 td->td_retval[0] = shmalloced;
  589                 goto done2;
  590         }
  591         }
  592         if (cmd == SHM_STAT)
  593                 shmseg = shm_find_segment_by_shmidx(shmid);
  594         else
  595                 shmseg = shm_find_segment_by_shmid(shmid);
  596         if (shmseg == NULL) {
  597                 error = EINVAL;
  598                 goto done2;
  599         }
  600 #ifdef MAC
  601         error = mac_check_sysv_shmctl(td->td_ucred, shmseg, cmd);
  602         if (error != 0) {
  603                 MPRINTF(("mac_check_sysv_shmctl returned %d\n", error));
  604                 goto done2;
  605         }
  606 #endif
  607         switch (cmd) {
  608         case SHM_STAT:
  609         case IPC_STAT:
  610                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
  611                 if (error)
  612                         goto done2;
  613                 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds));
  614                 if (bufsz)
  615                         *bufsz = sizeof(struct shmid_ds);
  616                 if (cmd == SHM_STAT)
  617                         td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm);
  618                 break;
  619         case IPC_SET: {
  620                 struct shmid_ds *shmid;
  621 
  622                 shmid = (struct shmid_ds *)buf;
  623                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
  624                 if (error)
  625                         goto done2;
  626                 shmseg->u.shm_perm.uid = shmid->shm_perm.uid;
  627                 shmseg->u.shm_perm.gid = shmid->shm_perm.gid;
  628                 shmseg->u.shm_perm.mode =
  629                     (shmseg->u.shm_perm.mode & ~ACCESSPERMS) |
  630                     (shmid->shm_perm.mode & ACCESSPERMS);
  631                 shmseg->u.shm_ctime = time_second;
  632                 break;
  633         }
  634         case IPC_RMID:
  635                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
  636                 if (error)
  637                         goto done2;
  638                 shmseg->u.shm_perm.key = IPC_PRIVATE;
  639                 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED;
  640                 if (shmseg->u.shm_nattch <= 0) {
  641                         shm_deallocate_segment(shmseg);
  642                         shm_last_free = IPCID_TO_IX(shmid);
  643                 }
  644                 break;
  645 #if 0
  646         case SHM_LOCK:
  647         case SHM_UNLOCK:
  648 #endif
  649         default:
  650                 error = EINVAL;
  651                 break;
  652         }
  653 done2:
  654         mtx_unlock(&Giant);
  655         return (error);
  656 }
  657 
  658 int
  659 shmctl(td, uap)
  660         struct thread *td;
  661         struct shmctl_args *uap;
  662 {
  663         int error = 0;
  664         struct shmid_ds buf;
  665         size_t bufsz;
  666         
  667         /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
  668         if (uap->cmd == IPC_SET) {
  669                 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
  670                         goto done;
  671         }
  672         
  673         error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
  674         if (error)
  675                 goto done;
  676         
  677         /* Cases in which we need to copyout */
  678         switch (uap->cmd) {
  679         case IPC_INFO:
  680         case SHM_INFO:
  681         case SHM_STAT:
  682         case IPC_STAT:
  683                 error = copyout(&buf, uap->buf, bufsz);
  684                 break;
  685         }
  686 
  687 done:
  688         if (error) {
  689                 /* Invalidate the return value */
  690                 td->td_retval[0] = -1;
  691         }
  692         return (error);
  693 }
  694 
  695 
  696 #ifndef _SYS_SYSPROTO_H_
  697 struct shmget_args {
  698         key_t key;
  699         size_t size;
  700         int shmflg;
  701 };
  702 #endif
  703 
  704 static int
  705 shmget_existing(td, uap, mode, segnum)
  706         struct thread *td;
  707         struct shmget_args *uap;
  708         int mode;
  709         int segnum;
  710 {
  711         struct shmid_kernel *shmseg;
  712         int error;
  713 
  714         shmseg = &shmsegs[segnum];
  715         if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) {
  716                 /*
  717                  * This segment is in the process of being allocated.  Wait
  718                  * until it's done, and look the key up again (in case the
  719                  * allocation failed or it was freed).
  720                  */
  721                 shmseg->u.shm_perm.mode |= SHMSEG_WANTED;
  722                 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
  723                 if (error)
  724                         return (error);
  725                 return (EAGAIN);
  726         }
  727         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
  728                 return (EEXIST);
  729         error = ipcperm(td, &shmseg->u.shm_perm, mode);
  730 #ifdef MAC
  731         error = mac_check_sysv_shmget(td->td_ucred, shmseg, uap->shmflg);
  732         if (error != 0)
  733                 MPRINTF(("mac_check_sysv_shmget returned %d\n", error));
  734 #endif
  735         if (error)
  736                 return (error);
  737         if (uap->size && uap->size > shmseg->u.shm_segsz)
  738                 return (EINVAL);
  739         td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
  740         return (0);
  741 }
  742 
  743 static int
  744 shmget_allocate_segment(td, uap, mode)
  745         struct thread *td;
  746         struct shmget_args *uap;
  747         int mode;
  748 {
  749         int i, segnum, shmid, size;
  750         struct ucred *cred = td->td_ucred;
  751         struct shmid_kernel *shmseg;
  752         vm_object_t shm_object;
  753 
  754         GIANT_REQUIRED;
  755 
  756         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
  757                 return (EINVAL);
  758         if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
  759                 return (ENOSPC);
  760         size = round_page(uap->size);
  761         if (shm_committed + btoc(size) > shminfo.shmall)
  762                 return (ENOMEM);
  763         if (shm_last_free < 0) {
  764                 shmrealloc();   /* Maybe expand the shmsegs[] array. */
  765                 for (i = 0; i < shmalloced; i++)
  766                         if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE)
  767                                 break;
  768                 if (i == shmalloced)
  769                         return (ENOSPC);
  770                 segnum = i;
  771         } else  {
  772                 segnum = shm_last_free;
  773                 shm_last_free = -1;
  774         }
  775         shmseg = &shmsegs[segnum];
  776         /*
  777          * In case we sleep in malloc(), mark the segment present but deleted
  778          * so that noone else tries to create the same key.
  779          */
  780         shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
  781         shmseg->u.shm_perm.key = uap->key;
  782         shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff;
  783         shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
  784         
  785         /*
  786          * We make sure that we have allocated a pager before we need
  787          * to.
  788          */
  789         if (shm_use_phys) {
  790                 shm_object =
  791                     vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0);
  792         } else {
  793                 shm_object =
  794                     vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
  795         }
  796         VM_OBJECT_LOCK(shm_object);
  797         vm_object_clear_flag(shm_object, OBJ_ONEMAPPING);
  798         vm_object_set_flag(shm_object, OBJ_NOSPLIT);
  799         VM_OBJECT_UNLOCK(shm_object);
  800 
  801         shmseg->u.shm_internal = shm_object;
  802         shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid;
  803         shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid;
  804         shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) |
  805             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
  806         shmseg->u.shm_segsz = uap->size;
  807         shmseg->u.shm_cpid = td->td_proc->p_pid;
  808         shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0;
  809         shmseg->u.shm_atime = shmseg->u.shm_dtime = 0;
  810 #ifdef MAC
  811         mac_create_sysv_shm(cred, shmseg);
  812 #endif
  813         shmseg->u.shm_ctime = time_second;
  814         shm_committed += btoc(size);
  815         shm_nused++;
  816         if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) {
  817                 /*
  818                  * Somebody else wanted this key while we were asleep.  Wake
  819                  * them up now.
  820                  */
  821                 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED;
  822                 wakeup(shmseg);
  823         }
  824         td->td_retval[0] = shmid;
  825         return (0);
  826 }
  827 
  828 /*
  829  * MPSAFE
  830  */
  831 int
  832 shmget(td, uap)
  833         struct thread *td;
  834         struct shmget_args *uap;
  835 {
  836         int segnum, mode;
  837         int error;
  838 
  839         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
  840                 return (ENOSYS);
  841         mtx_lock(&Giant);
  842         mode = uap->shmflg & ACCESSPERMS;
  843         if (uap->key != IPC_PRIVATE) {
  844         again:
  845                 segnum = shm_find_segment_by_key(uap->key);
  846                 if (segnum >= 0) {
  847                         error = shmget_existing(td, uap, mode, segnum);
  848                         if (error == EAGAIN)
  849                                 goto again;
  850                         goto done2;
  851                 }
  852                 if ((uap->shmflg & IPC_CREAT) == 0) {
  853                         error = ENOENT;
  854                         goto done2;
  855                 }
  856         }
  857         error = shmget_allocate_segment(td, uap, mode);
  858 done2:
  859         mtx_unlock(&Giant);
  860         return (error);
  861 }
  862 
  863 /*
  864  * MPSAFE
  865  */
  866 int
  867 shmsys(td, uap)
  868         struct thread *td;
  869         /* XXX actually varargs. */
  870         struct shmsys_args /* {
  871                 int     which;
  872                 int     a2;
  873                 int     a3;
  874                 int     a4;
  875         } */ *uap;
  876 {
  877         int error;
  878 
  879         if (!jail_sysvipc_allowed && jailed(td->td_ucred))
  880                 return (ENOSYS);
  881         if (uap->which < 0 ||
  882             uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
  883                 return (EINVAL);
  884         mtx_lock(&Giant);
  885         error = (*shmcalls[uap->which])(td, &uap->a2);
  886         mtx_unlock(&Giant);
  887         return (error);
  888 }
  889 
  890 static void
  891 shmfork_myhook(p1, p2)
  892         struct proc *p1, *p2;
  893 {
  894         struct shmmap_state *shmmap_s;
  895         size_t size;
  896         int i;
  897 
  898         mtx_lock(&Giant);
  899         size = shminfo.shmseg * sizeof(struct shmmap_state);
  900         shmmap_s = malloc(size, M_SHM, M_WAITOK);
  901         bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
  902         p2->p_vmspace->vm_shm = shmmap_s;
  903         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
  904                 if (shmmap_s->shmid != -1)
  905                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++;
  906         mtx_unlock(&Giant);
  907 }
  908 
  909 static void
  910 shmexit_myhook(struct vmspace *vm)
  911 {
  912         struct shmmap_state *base, *shm;
  913         int i;
  914 
  915         if ((base = vm->vm_shm) != NULL) {
  916                 vm->vm_shm = NULL;
  917                 mtx_lock(&Giant);
  918                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
  919                         if (shm->shmid != -1)
  920                                 shm_delete_mapping(vm, shm);
  921                 }
  922                 mtx_unlock(&Giant);
  923                 free(base, M_SHM);
  924         }
  925 }
  926 
  927 static void
  928 shmrealloc(void)
  929 {
  930         int i;
  931         struct shmid_kernel *newsegs;
  932 
  933         if (shmalloced >= shminfo.shmmni)
  934                 return;
  935 
  936         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
  937         if (newsegs == NULL)
  938                 return;
  939         for (i = 0; i < shmalloced; i++)
  940                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
  941         for (; i < shminfo.shmmni; i++) {
  942                 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
  943                 shmsegs[i].u.shm_perm.seq = 0;
  944 #ifdef MAC
  945                 mac_init_sysv_shm(&shmsegs[i]);
  946 #endif
  947         }
  948         free(shmsegs, M_SHM);
  949         shmsegs = newsegs;
  950         shmalloced = shminfo.shmmni;
  951 }
  952 
  953 static void
  954 shminit()
  955 {
  956         int i;
  957 
  958         TUNABLE_INT_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall);
  959         for (i = PAGE_SIZE; i > 0; i--) {
  960                 shminfo.shmmax = shminfo.shmall * i;
  961                 if (shminfo.shmmax >= shminfo.shmall)
  962                         break;
  963         }
  964         TUNABLE_INT_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
  965         TUNABLE_INT_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
  966         TUNABLE_INT_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
  967         TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
  968 
  969         shmalloced = shminfo.shmmni;
  970         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
  971         if (shmsegs == NULL)
  972                 panic("cannot allocate initial memory for sysvshm");
  973         for (i = 0; i < shmalloced; i++) {
  974                 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
  975                 shmsegs[i].u.shm_perm.seq = 0;
  976 #ifdef MAC
  977                 mac_init_sysv_shm(&shmsegs[i]);
  978 #endif
  979         }
  980         shm_last_free = 0;
  981         shm_nused = 0;
  982         shm_committed = 0;
  983         shmexit_hook = &shmexit_myhook;
  984         shmfork_hook = &shmfork_myhook;
  985 }
  986 
  987 static int
  988 shmunload()
  989 {
  990 #ifdef MAC
  991         int i;  
  992 #endif
  993 
  994         if (shm_nused > 0)
  995                 return (EBUSY);
  996 
  997 #ifdef MAC
  998         for (i = 0; i < shmalloced; i++)
  999                 mac_destroy_sysv_shm(&shmsegs[i]);
 1000 #endif
 1001         free(shmsegs, M_SHM);
 1002         shmexit_hook = NULL;
 1003         shmfork_hook = NULL;
 1004         return (0);
 1005 }
 1006 
 1007 static int
 1008 sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
 1009 {
 1010 
 1011         return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
 1012 }
 1013 
 1014 static int
 1015 sysvshm_modload(struct module *module, int cmd, void *arg)
 1016 {
 1017         int error = 0;
 1018 
 1019         switch (cmd) {
 1020         case MOD_LOAD:
 1021                 shminit();
 1022                 break;
 1023         case MOD_UNLOAD:
 1024                 error = shmunload();
 1025                 break;
 1026         case MOD_SHUTDOWN:
 1027                 break;
 1028         default:
 1029                 error = EINVAL;
 1030                 break;
 1031         }
 1032         return (error);
 1033 }
 1034 
 1035 static moduledata_t sysvshm_mod = {
 1036         "sysvshm",
 1037         &sysvshm_modload,
 1038         NULL
 1039 };
 1040 
 1041 SYSCALL_MODULE_HELPER(shmsys);
 1042 SYSCALL_MODULE_HELPER(shmat);
 1043 SYSCALL_MODULE_HELPER(shmctl);
 1044 SYSCALL_MODULE_HELPER(shmdt);
 1045 SYSCALL_MODULE_HELPER(shmget);
 1046 
 1047 DECLARE_MODULE(sysvshm, sysvshm_mod,
 1048         SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
 1049 MODULE_VERSION(sysvshm, 1);

Cache object: 25eb8af261b63f16b70ad1bbb3af91cd


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