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


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

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

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    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: releng/8.0/sys/kern/sysv_shm.c 194976 2009-06-25 17:11:27Z jhb $");
   64 
   65 #include "opt_compat.h"
   66 #include "opt_sysvipc.h"
   67 
   68 #include <sys/param.h>
   69 #include <sys/systm.h>
   70 #include <sys/kernel.h>
   71 #include <sys/limits.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 
   88 #include <security/mac/mac_framework.h>
   89 
   90 #include <vm/vm.h>
   91 #include <vm/vm_param.h>
   92 #include <vm/pmap.h>
   93 #include <vm/vm_object.h>
   94 #include <vm/vm_map.h>
   95 #include <vm/vm_page.h>
   96 #include <vm/vm_pager.h>
   97 
   98 static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
   99 
  100 static int shmget_allocate_segment(struct thread *td,
  101     struct shmget_args *uap, int mode);
  102 static int shmget_existing(struct thread *td, struct shmget_args *uap,
  103     int mode, int segnum);
  104 
  105 #define SHMSEG_FREE             0x0200
  106 #define SHMSEG_REMOVED          0x0400
  107 #define SHMSEG_ALLOCATED        0x0800
  108 #define SHMSEG_WANTED           0x1000
  109 
  110 static int shm_last_free, shm_nused, shmalloced;
  111 vm_size_t shm_committed;
  112 static struct shmid_kernel      *shmsegs;
  113 
  114 struct shmmap_state {
  115         vm_offset_t va;
  116         int shmid;
  117 };
  118 
  119 static void shm_deallocate_segment(struct shmid_kernel *);
  120 static int shm_find_segment_by_key(key_t);
  121 static struct shmid_kernel *shm_find_segment_by_shmid(int);
  122 static struct shmid_kernel *shm_find_segment_by_shmidx(int);
  123 static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
  124 static void shmrealloc(void);
  125 static void shminit(void);
  126 static int sysvshm_modload(struct module *, int, void *);
  127 static int shmunload(void);
  128 static void shmexit_myhook(struct vmspace *vm);
  129 static void shmfork_myhook(struct proc *p1, struct proc *p2);
  130 static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
  131 
  132 /*
  133  * Tuneable values.
  134  */
  135 #ifndef SHMMAXPGS
  136 #define SHMMAXPGS       8192    /* Note: sysv shared memory is swap backed. */
  137 #endif
  138 #ifndef SHMMAX
  139 #define SHMMAX  (SHMMAXPGS*PAGE_SIZE)
  140 #endif
  141 #ifndef SHMMIN
  142 #define SHMMIN  1
  143 #endif
  144 #ifndef SHMMNI
  145 #define SHMMNI  192
  146 #endif
  147 #ifndef SHMSEG
  148 #define SHMSEG  128
  149 #endif
  150 #ifndef SHMALL
  151 #define SHMALL  (SHMMAXPGS)
  152 #endif
  153 
  154 struct  shminfo shminfo = {
  155         SHMMAX,
  156         SHMMIN,
  157         SHMMNI,
  158         SHMSEG,
  159         SHMALL
  160 };
  161 
  162 static int shm_use_phys;
  163 static int shm_allow_removed;
  164 
  165 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
  166     "Maximum shared memory segment size");
  167 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
  168     "Minimum shared memory segment size");
  169 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0,
  170     "Number of shared memory identifiers");
  171 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0,
  172     "Number of segments per process");
  173 SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
  174     "Maximum number of pages available for shared memory");
  175 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
  176     &shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
  177 SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
  178     &shm_allow_removed, 0,
  179     "Enable/Disable attachment to attached segments marked for removal");
  180 SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLFLAG_RD,
  181     NULL, 0, sysctl_shmsegs, "",
  182     "Current number of shared memory segments allocated");
  183 
  184 static int
  185 shm_find_segment_by_key(key)
  186         key_t key;
  187 {
  188         int i;
  189 
  190         for (i = 0; i < shmalloced; i++)
  191                 if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) &&
  192                     shmsegs[i].u.shm_perm.key == key)
  193                         return (i);
  194         return (-1);
  195 }
  196 
  197 static struct shmid_kernel *
  198 shm_find_segment_by_shmid(int shmid)
  199 {
  200         int segnum;
  201         struct shmid_kernel *shmseg;
  202 
  203         segnum = IPCID_TO_IX(shmid);
  204         if (segnum < 0 || segnum >= shmalloced)
  205                 return (NULL);
  206         shmseg = &shmsegs[segnum];
  207         if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
  208             (!shm_allow_removed &&
  209              (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) ||
  210             shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid))
  211                 return (NULL);
  212         return (shmseg);
  213 }
  214 
  215 static struct shmid_kernel *
  216 shm_find_segment_by_shmidx(int segnum)
  217 {
  218         struct shmid_kernel *shmseg;
  219 
  220         if (segnum < 0 || segnum >= shmalloced)
  221                 return (NULL);
  222         shmseg = &shmsegs[segnum];
  223         if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
  224             (!shm_allow_removed &&
  225              (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0))
  226                 return (NULL);
  227         return (shmseg);
  228 }
  229 
  230 static void
  231 shm_deallocate_segment(shmseg)
  232         struct shmid_kernel *shmseg;
  233 {
  234         vm_size_t size;
  235 
  236         GIANT_REQUIRED;
  237 
  238         vm_object_deallocate(shmseg->object);
  239         shmseg->object = NULL;
  240         size = round_page(shmseg->u.shm_segsz);
  241         shm_committed -= btoc(size);
  242         shm_nused--;
  243         shmseg->u.shm_perm.mode = SHMSEG_FREE;
  244 #ifdef MAC
  245         mac_sysvshm_cleanup(shmseg);
  246 #endif
  247 }
  248 
  249 static int
  250 shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
  251 {
  252         struct shmid_kernel *shmseg;
  253         int segnum, result;
  254         vm_size_t size;
  255 
  256         GIANT_REQUIRED;
  257 
  258         segnum = IPCID_TO_IX(shmmap_s->shmid);
  259         shmseg = &shmsegs[segnum];
  260         size = round_page(shmseg->u.shm_segsz);
  261         result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
  262         if (result != KERN_SUCCESS)
  263                 return (EINVAL);
  264         shmmap_s->shmid = -1;
  265         shmseg->u.shm_dtime = time_second;
  266         if ((--shmseg->u.shm_nattch <= 0) &&
  267             (shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) {
  268                 shm_deallocate_segment(shmseg);
  269                 shm_last_free = segnum;
  270         }
  271         return (0);
  272 }
  273 
  274 #ifndef _SYS_SYSPROTO_H_
  275 struct shmdt_args {
  276         const void *shmaddr;
  277 };
  278 #endif
  279 int
  280 shmdt(td, uap)
  281         struct thread *td;
  282         struct shmdt_args *uap;
  283 {
  284         struct proc *p = td->td_proc;
  285         struct shmmap_state *shmmap_s;
  286 #ifdef MAC
  287         struct shmid_kernel *shmsegptr;
  288 #endif
  289         int i;
  290         int error = 0;
  291 
  292         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  293                 return (ENOSYS);
  294         mtx_lock(&Giant);
  295         shmmap_s = p->p_vmspace->vm_shm;
  296         if (shmmap_s == NULL) {
  297                 error = EINVAL;
  298                 goto done2;
  299         }
  300         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
  301                 if (shmmap_s->shmid != -1 &&
  302                     shmmap_s->va == (vm_offset_t)uap->shmaddr) {
  303                         break;
  304                 }
  305         }
  306         if (i == shminfo.shmseg) {
  307                 error = EINVAL;
  308                 goto done2;
  309         }
  310 #ifdef MAC
  311         shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)];
  312         error = mac_sysvshm_check_shmdt(td->td_ucred, shmsegptr);
  313         if (error != 0)
  314                 goto done2;
  315 #endif
  316         error = shm_delete_mapping(p->p_vmspace, shmmap_s);
  317 done2:
  318         mtx_unlock(&Giant);
  319         return (error);
  320 }
  321 
  322 #ifndef _SYS_SYSPROTO_H_
  323 struct shmat_args {
  324         int shmid;
  325         const void *shmaddr;
  326         int shmflg;
  327 };
  328 #endif
  329 int
  330 kern_shmat(td, shmid, shmaddr, shmflg)
  331         struct thread *td;
  332         int shmid;
  333         const void *shmaddr;
  334         int shmflg;
  335 {
  336         struct proc *p = td->td_proc;
  337         int i, flags;
  338         struct shmid_kernel *shmseg;
  339         struct shmmap_state *shmmap_s = NULL;
  340         vm_offset_t attach_va;
  341         vm_prot_t prot;
  342         vm_size_t size;
  343         int rv;
  344         int error = 0;
  345 
  346         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  347                 return (ENOSYS);
  348         mtx_lock(&Giant);
  349         shmmap_s = p->p_vmspace->vm_shm;
  350         if (shmmap_s == NULL) {
  351                 shmmap_s = malloc(shminfo.shmseg * sizeof(struct shmmap_state),
  352                     M_SHM, M_WAITOK);
  353                 for (i = 0; i < shminfo.shmseg; i++)
  354                         shmmap_s[i].shmid = -1;
  355                 p->p_vmspace->vm_shm = shmmap_s;
  356         }
  357         shmseg = shm_find_segment_by_shmid(shmid);
  358         if (shmseg == NULL) {
  359                 error = EINVAL;
  360                 goto done2;
  361         }
  362         error = ipcperm(td, &shmseg->u.shm_perm,
  363             (shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
  364         if (error)
  365                 goto done2;
  366 #ifdef MAC
  367         error = mac_sysvshm_check_shmat(td->td_ucred, shmseg, shmflg);
  368         if (error != 0)
  369                 goto done2;
  370 #endif
  371         for (i = 0; i < shminfo.shmseg; i++) {
  372                 if (shmmap_s->shmid == -1)
  373                         break;
  374                 shmmap_s++;
  375         }
  376         if (i >= shminfo.shmseg) {
  377                 error = EMFILE;
  378                 goto done2;
  379         }
  380         size = round_page(shmseg->u.shm_segsz);
  381         prot = VM_PROT_READ;
  382         if ((shmflg & SHM_RDONLY) == 0)
  383                 prot |= VM_PROT_WRITE;
  384         flags = MAP_ANON | MAP_SHARED;
  385         if (shmaddr) {
  386                 flags |= MAP_FIXED;
  387                 if (shmflg & SHM_RND) {
  388                         attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
  389                 } else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
  390                         attach_va = (vm_offset_t)shmaddr;
  391                 } else {
  392                         error = EINVAL;
  393                         goto done2;
  394                 }
  395         } else {
  396                 /*
  397                  * This is just a hint to vm_map_find() about where to
  398                  * put it.
  399                  */
  400                 PROC_LOCK(p);
  401                 attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
  402                     lim_max(p, RLIMIT_DATA));
  403                 PROC_UNLOCK(p);
  404         }
  405 
  406         vm_object_reference(shmseg->object);
  407         rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->object,
  408             0, &attach_va, size, (flags & MAP_FIXED) ? VMFS_NO_SPACE :
  409             VMFS_ANY_SPACE, prot, prot, 0);
  410         if (rv != KERN_SUCCESS) {
  411                 vm_object_deallocate(shmseg->object);
  412                 error = ENOMEM;
  413                 goto done2;
  414         }
  415         vm_map_inherit(&p->p_vmspace->vm_map,
  416                 attach_va, attach_va + size, VM_INHERIT_SHARE);
  417 
  418         shmmap_s->va = attach_va;
  419         shmmap_s->shmid = shmid;
  420         shmseg->u.shm_lpid = p->p_pid;
  421         shmseg->u.shm_atime = time_second;
  422         shmseg->u.shm_nattch++;
  423         td->td_retval[0] = attach_va;
  424 done2:
  425         mtx_unlock(&Giant);
  426         return (error);
  427 }
  428 
  429 int
  430 shmat(td, uap)
  431         struct thread *td;
  432         struct shmat_args *uap;
  433 {
  434         return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg);
  435 }
  436 
  437 int
  438 kern_shmctl(td, shmid, cmd, buf, bufsz)
  439         struct thread *td;
  440         int shmid;
  441         int cmd;
  442         void *buf;
  443         size_t *bufsz;
  444 {
  445         int error = 0;
  446         struct shmid_kernel *shmseg;
  447 
  448         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  449                 return (ENOSYS);
  450 
  451         mtx_lock(&Giant);
  452         switch (cmd) {
  453         /*
  454          * It is possible that kern_shmctl is being called from the Linux ABI
  455          * layer, in which case, we will need to implement IPC_INFO.  It should
  456          * be noted that other shmctl calls will be funneled through here for
  457          * Linix binaries as well.
  458          *
  459          * NB: The Linux ABI layer will convert this data to structure(s) more
  460          * consistent with the Linux ABI.
  461          */
  462         case IPC_INFO:
  463                 memcpy(buf, &shminfo, sizeof(shminfo));
  464                 if (bufsz)
  465                         *bufsz = sizeof(shminfo);
  466                 td->td_retval[0] = shmalloced;
  467                 goto done2;
  468         case SHM_INFO: {
  469                 struct shm_info shm_info;
  470                 shm_info.used_ids = shm_nused;
  471                 shm_info.shm_rss = 0;   /*XXX where to get from ? */
  472                 shm_info.shm_tot = 0;   /*XXX where to get from ? */
  473                 shm_info.shm_swp = 0;   /*XXX where to get from ? */
  474                 shm_info.swap_attempts = 0;     /*XXX where to get from ? */
  475                 shm_info.swap_successes = 0;    /*XXX where to get from ? */
  476                 memcpy(buf, &shm_info, sizeof(shm_info));
  477                 if (bufsz)
  478                         *bufsz = sizeof(shm_info);
  479                 td->td_retval[0] = shmalloced;
  480                 goto done2;
  481         }
  482         }
  483         if (cmd == SHM_STAT)
  484                 shmseg = shm_find_segment_by_shmidx(shmid);
  485         else
  486                 shmseg = shm_find_segment_by_shmid(shmid);
  487         if (shmseg == NULL) {
  488                 error = EINVAL;
  489                 goto done2;
  490         }
  491 #ifdef MAC
  492         error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd);
  493         if (error != 0)
  494                 goto done2;
  495 #endif
  496         switch (cmd) {
  497         case SHM_STAT:
  498         case IPC_STAT:
  499                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
  500                 if (error)
  501                         goto done2;
  502                 memcpy(buf, &shmseg->u, sizeof(struct shmid_ds));
  503                 if (bufsz)
  504                         *bufsz = sizeof(struct shmid_ds);
  505                 if (cmd == SHM_STAT)
  506                         td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm);
  507                 break;
  508         case IPC_SET: {
  509                 struct shmid_ds *shmid;
  510 
  511                 shmid = (struct shmid_ds *)buf;
  512                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
  513                 if (error)
  514                         goto done2;
  515                 shmseg->u.shm_perm.uid = shmid->shm_perm.uid;
  516                 shmseg->u.shm_perm.gid = shmid->shm_perm.gid;
  517                 shmseg->u.shm_perm.mode =
  518                     (shmseg->u.shm_perm.mode & ~ACCESSPERMS) |
  519                     (shmid->shm_perm.mode & ACCESSPERMS);
  520                 shmseg->u.shm_ctime = time_second;
  521                 break;
  522         }
  523         case IPC_RMID:
  524                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
  525                 if (error)
  526                         goto done2;
  527                 shmseg->u.shm_perm.key = IPC_PRIVATE;
  528                 shmseg->u.shm_perm.mode |= SHMSEG_REMOVED;
  529                 if (shmseg->u.shm_nattch <= 0) {
  530                         shm_deallocate_segment(shmseg);
  531                         shm_last_free = IPCID_TO_IX(shmid);
  532                 }
  533                 break;
  534 #if 0
  535         case SHM_LOCK:
  536         case SHM_UNLOCK:
  537 #endif
  538         default:
  539                 error = EINVAL;
  540                 break;
  541         }
  542 done2:
  543         mtx_unlock(&Giant);
  544         return (error);
  545 }
  546 
  547 #ifndef _SYS_SYSPROTO_H_
  548 struct shmctl_args {
  549         int shmid;
  550         int cmd;
  551         struct shmid_ds *buf;
  552 };
  553 #endif
  554 int
  555 shmctl(td, uap)
  556         struct thread *td;
  557         struct shmctl_args *uap;
  558 {
  559         int error = 0;
  560         struct shmid_ds buf;
  561         size_t bufsz;
  562         
  563         /*
  564          * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support
  565          * Linux binaries.  If we see the call come through the FreeBSD ABI,
  566          * return an error back to the user since we do not to support this.
  567          */
  568         if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO ||
  569             uap->cmd == SHM_STAT)
  570                 return (EINVAL);
  571 
  572         /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
  573         if (uap->cmd == IPC_SET) {
  574                 if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
  575                         goto done;
  576         }
  577         
  578         error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
  579         if (error)
  580                 goto done;
  581         
  582         /* Cases in which we need to copyout */
  583         switch (uap->cmd) {
  584         case IPC_STAT:
  585                 error = copyout(&buf, uap->buf, bufsz);
  586                 break;
  587         }
  588 
  589 done:
  590         if (error) {
  591                 /* Invalidate the return value */
  592                 td->td_retval[0] = -1;
  593         }
  594         return (error);
  595 }
  596 
  597 
  598 static int
  599 shmget_existing(td, uap, mode, segnum)
  600         struct thread *td;
  601         struct shmget_args *uap;
  602         int mode;
  603         int segnum;
  604 {
  605         struct shmid_kernel *shmseg;
  606         int error;
  607 
  608         shmseg = &shmsegs[segnum];
  609         if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) {
  610                 /*
  611                  * This segment is in the process of being allocated.  Wait
  612                  * until it's done, and look the key up again (in case the
  613                  * allocation failed or it was freed).
  614                  */
  615                 shmseg->u.shm_perm.mode |= SHMSEG_WANTED;
  616                 error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
  617                 if (error)
  618                         return (error);
  619                 return (EAGAIN);
  620         }
  621         if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
  622                 return (EEXIST);
  623 #ifdef MAC
  624         error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg);
  625         if (error != 0)
  626                 return (error);
  627 #endif
  628         if (uap->size != 0 && uap->size > shmseg->u.shm_segsz)
  629                 return (EINVAL);
  630         td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
  631         return (0);
  632 }
  633 
  634 static int
  635 shmget_allocate_segment(td, uap, mode)
  636         struct thread *td;
  637         struct shmget_args *uap;
  638         int mode;
  639 {
  640         int i, segnum, shmid;
  641         size_t size;
  642         struct ucred *cred = td->td_ucred;
  643         struct shmid_kernel *shmseg;
  644         vm_object_t shm_object;
  645 
  646         GIANT_REQUIRED;
  647 
  648         if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
  649                 return (EINVAL);
  650         if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
  651                 return (ENOSPC);
  652         size = round_page(uap->size);
  653         if (shm_committed + btoc(size) > shminfo.shmall)
  654                 return (ENOMEM);
  655         if (shm_last_free < 0) {
  656                 shmrealloc();   /* Maybe expand the shmsegs[] array. */
  657                 for (i = 0; i < shmalloced; i++)
  658                         if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE)
  659                                 break;
  660                 if (i == shmalloced)
  661                         return (ENOSPC);
  662                 segnum = i;
  663         } else  {
  664                 segnum = shm_last_free;
  665                 shm_last_free = -1;
  666         }
  667         shmseg = &shmsegs[segnum];
  668         /*
  669          * In case we sleep in malloc(), mark the segment present but deleted
  670          * so that noone else tries to create the same key.
  671          */
  672         shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
  673         shmseg->u.shm_perm.key = uap->key;
  674         shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff;
  675         shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
  676         
  677         /*
  678          * We make sure that we have allocated a pager before we need
  679          * to.
  680          */
  681         shm_object = vm_pager_allocate(shm_use_phys ? OBJT_PHYS : OBJT_SWAP,
  682             0, size, VM_PROT_DEFAULT, 0, cred);
  683         if (shm_object == NULL)
  684                 return (ENOMEM);
  685         VM_OBJECT_LOCK(shm_object);
  686         vm_object_clear_flag(shm_object, OBJ_ONEMAPPING);
  687         vm_object_set_flag(shm_object, OBJ_NOSPLIT);
  688         VM_OBJECT_UNLOCK(shm_object);
  689 
  690         shmseg->object = shm_object;
  691         shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid;
  692         shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid;
  693         shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) |
  694             (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
  695         shmseg->u.shm_segsz = uap->size;
  696         shmseg->u.shm_cpid = td->td_proc->p_pid;
  697         shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0;
  698         shmseg->u.shm_atime = shmseg->u.shm_dtime = 0;
  699 #ifdef MAC
  700         mac_sysvshm_create(cred, shmseg);
  701 #endif
  702         shmseg->u.shm_ctime = time_second;
  703         shm_committed += btoc(size);
  704         shm_nused++;
  705         if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) {
  706                 /*
  707                  * Somebody else wanted this key while we were asleep.  Wake
  708                  * them up now.
  709                  */
  710                 shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED;
  711                 wakeup(shmseg);
  712         }
  713         td->td_retval[0] = shmid;
  714         return (0);
  715 }
  716 
  717 #ifndef _SYS_SYSPROTO_H_
  718 struct shmget_args {
  719         key_t key;
  720         size_t size;
  721         int shmflg;
  722 };
  723 #endif
  724 int
  725 shmget(td, uap)
  726         struct thread *td;
  727         struct shmget_args *uap;
  728 {
  729         int segnum, mode;
  730         int error;
  731 
  732         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  733                 return (ENOSYS);
  734         mtx_lock(&Giant);
  735         mode = uap->shmflg & ACCESSPERMS;
  736         if (uap->key != IPC_PRIVATE) {
  737         again:
  738                 segnum = shm_find_segment_by_key(uap->key);
  739                 if (segnum >= 0) {
  740                         error = shmget_existing(td, uap, mode, segnum);
  741                         if (error == EAGAIN)
  742                                 goto again;
  743                         goto done2;
  744                 }
  745                 if ((uap->shmflg & IPC_CREAT) == 0) {
  746                         error = ENOENT;
  747                         goto done2;
  748                 }
  749         }
  750         error = shmget_allocate_segment(td, uap, mode);
  751 done2:
  752         mtx_unlock(&Giant);
  753         return (error);
  754 }
  755 
  756 static void
  757 shmfork_myhook(p1, p2)
  758         struct proc *p1, *p2;
  759 {
  760         struct shmmap_state *shmmap_s;
  761         size_t size;
  762         int i;
  763 
  764         mtx_lock(&Giant);
  765         size = shminfo.shmseg * sizeof(struct shmmap_state);
  766         shmmap_s = malloc(size, M_SHM, M_WAITOK);
  767         bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
  768         p2->p_vmspace->vm_shm = shmmap_s;
  769         for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
  770                 if (shmmap_s->shmid != -1)
  771                         shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++;
  772         mtx_unlock(&Giant);
  773 }
  774 
  775 static void
  776 shmexit_myhook(struct vmspace *vm)
  777 {
  778         struct shmmap_state *base, *shm;
  779         int i;
  780 
  781         if ((base = vm->vm_shm) != NULL) {
  782                 vm->vm_shm = NULL;
  783                 mtx_lock(&Giant);
  784                 for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
  785                         if (shm->shmid != -1)
  786                                 shm_delete_mapping(vm, shm);
  787                 }
  788                 mtx_unlock(&Giant);
  789                 free(base, M_SHM);
  790         }
  791 }
  792 
  793 static void
  794 shmrealloc(void)
  795 {
  796         int i;
  797         struct shmid_kernel *newsegs;
  798 
  799         if (shmalloced >= shminfo.shmmni)
  800                 return;
  801 
  802         newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
  803         if (newsegs == NULL)
  804                 return;
  805         for (i = 0; i < shmalloced; i++)
  806                 bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
  807         for (; i < shminfo.shmmni; i++) {
  808                 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
  809                 shmsegs[i].u.shm_perm.seq = 0;
  810 #ifdef MAC
  811                 mac_sysvshm_init(&shmsegs[i]);
  812 #endif
  813         }
  814         free(shmsegs, M_SHM);
  815         shmsegs = newsegs;
  816         shmalloced = shminfo.shmmni;
  817 }
  818 
  819 static void
  820 shminit()
  821 {
  822         int i;
  823 
  824         TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall);
  825         for (i = PAGE_SIZE; i > 0; i--) {
  826                 shminfo.shmmax = shminfo.shmall * i;
  827                 if (shminfo.shmmax >= shminfo.shmall)
  828                         break;
  829         }
  830         TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
  831         TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
  832         TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
  833         TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
  834 
  835         shmalloced = shminfo.shmmni;
  836         shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
  837         if (shmsegs == NULL)
  838                 panic("cannot allocate initial memory for sysvshm");
  839         for (i = 0; i < shmalloced; i++) {
  840                 shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
  841                 shmsegs[i].u.shm_perm.seq = 0;
  842 #ifdef MAC
  843                 mac_sysvshm_init(&shmsegs[i]);
  844 #endif
  845         }
  846         shm_last_free = 0;
  847         shm_nused = 0;
  848         shm_committed = 0;
  849         shmexit_hook = &shmexit_myhook;
  850         shmfork_hook = &shmfork_myhook;
  851 }
  852 
  853 static int
  854 shmunload()
  855 {
  856 #ifdef MAC
  857         int i;  
  858 #endif
  859 
  860         if (shm_nused > 0)
  861                 return (EBUSY);
  862 
  863 #ifdef MAC
  864         for (i = 0; i < shmalloced; i++)
  865                 mac_sysvshm_destroy(&shmsegs[i]);
  866 #endif
  867         free(shmsegs, M_SHM);
  868         shmexit_hook = NULL;
  869         shmfork_hook = NULL;
  870         return (0);
  871 }
  872 
  873 static int
  874 sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
  875 {
  876 
  877         return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
  878 }
  879 
  880 #if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43))
  881 struct oshmid_ds {
  882         struct  ipc_perm_old shm_perm;  /* operation perms */
  883         int     shm_segsz;              /* size of segment (bytes) */
  884         u_short shm_cpid;               /* pid, creator */
  885         u_short shm_lpid;               /* pid, last operation */
  886         short   shm_nattch;             /* no. of current attaches */
  887         time_t  shm_atime;              /* last attach time */
  888         time_t  shm_dtime;              /* last detach time */
  889         time_t  shm_ctime;              /* last change time */
  890         void    *shm_handle;            /* internal handle for shm segment */
  891 };
  892 
  893 struct oshmctl_args {
  894         int shmid;
  895         int cmd;
  896         struct oshmid_ds *ubuf;
  897 };
  898 
  899 static int
  900 oshmctl(struct thread *td, struct oshmctl_args *uap)
  901 {
  902 #ifdef COMPAT_43
  903         int error = 0;
  904         struct shmid_kernel *shmseg;
  905         struct oshmid_ds outbuf;
  906 
  907         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  908                 return (ENOSYS);
  909         mtx_lock(&Giant);
  910         shmseg = shm_find_segment_by_shmid(uap->shmid);
  911         if (shmseg == NULL) {
  912                 error = EINVAL;
  913                 goto done2;
  914         }
  915         switch (uap->cmd) {
  916         case IPC_STAT:
  917                 error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
  918                 if (error)
  919                         goto done2;
  920 #ifdef MAC
  921                 error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd);
  922                 if (error != 0)
  923                         goto done2;
  924 #endif
  925                 ipcperm_new2old(&shmseg->u.shm_perm, &outbuf.shm_perm);
  926                 outbuf.shm_segsz = shmseg->u.shm_segsz;
  927                 outbuf.shm_cpid = shmseg->u.shm_cpid;
  928                 outbuf.shm_lpid = shmseg->u.shm_lpid;
  929                 outbuf.shm_nattch = shmseg->u.shm_nattch;
  930                 outbuf.shm_atime = shmseg->u.shm_atime;
  931                 outbuf.shm_dtime = shmseg->u.shm_dtime;
  932                 outbuf.shm_ctime = shmseg->u.shm_ctime;
  933                 outbuf.shm_handle = shmseg->object;
  934                 error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
  935                 if (error)
  936                         goto done2;
  937                 break;
  938         default:
  939                 error = freebsd7_shmctl(td, (struct freebsd7_shmctl_args *)uap);
  940                 break;
  941         }
  942 done2:
  943         mtx_unlock(&Giant);
  944         return (error);
  945 #else
  946         return (EINVAL);
  947 #endif
  948 }
  949 
  950 /* XXX casting to (sy_call_t *) is bogus, as usual. */
  951 static sy_call_t *shmcalls[] = {
  952         (sy_call_t *)shmat, (sy_call_t *)oshmctl,
  953         (sy_call_t *)shmdt, (sy_call_t *)shmget,
  954         (sy_call_t *)freebsd7_shmctl
  955 };
  956 
  957 int
  958 shmsys(td, uap)
  959         struct thread *td;
  960         /* XXX actually varargs. */
  961         struct shmsys_args /* {
  962                 int     which;
  963                 int     a2;
  964                 int     a3;
  965                 int     a4;
  966         } */ *uap;
  967 {
  968         int error;
  969 
  970         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  971                 return (ENOSYS);
  972         if (uap->which < 0 ||
  973             uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
  974                 return (EINVAL);
  975         mtx_lock(&Giant);
  976         error = (*shmcalls[uap->which])(td, &uap->a2);
  977         mtx_unlock(&Giant);
  978         return (error);
  979 }
  980 
  981 SYSCALL_MODULE_HELPER(shmsys);
  982 #endif  /* i386 && (COMPAT_FREEBSD4 || COMPAT_43) */
  983 
  984 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
  985     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
  986 
  987 #define CP(src, dst, fld)       do { (dst).fld = (src).fld; } while (0)
  988 
  989 
  990 #ifndef _SYS_SYSPROTO_H_
  991 struct freebsd7_shmctl_args {
  992         int shmid;
  993         int cmd;
  994         struct shmid_ds_old *buf;
  995 };
  996 #endif
  997 int
  998 freebsd7_shmctl(td, uap)
  999         struct thread *td;
 1000         struct freebsd7_shmctl_args *uap;
 1001 {
 1002         int error = 0;
 1003         struct shmid_ds_old old;
 1004         struct shmid_ds buf;
 1005         size_t bufsz;
 1006         
 1007         /*
 1008          * The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support
 1009          * Linux binaries.  If we see the call come through the FreeBSD ABI,
 1010          * return an error back to the user since we do not to support this.
 1011          */
 1012         if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO ||
 1013             uap->cmd == SHM_STAT)
 1014                 return (EINVAL);
 1015 
 1016         /* IPC_SET needs to copyin the buffer before calling kern_shmctl */
 1017         if (uap->cmd == IPC_SET) {
 1018                 if ((error = copyin(uap->buf, &old, sizeof(old))))
 1019                         goto done;
 1020                 ipcperm_old2new(&old.shm_perm, &buf.shm_perm);
 1021                 CP(old, buf, shm_segsz);
 1022                 CP(old, buf, shm_lpid);
 1023                 CP(old, buf, shm_cpid);
 1024                 CP(old, buf, shm_nattch);
 1025                 CP(old, buf, shm_atime);
 1026                 CP(old, buf, shm_dtime);
 1027                 CP(old, buf, shm_ctime);
 1028         }
 1029         
 1030         error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
 1031         if (error)
 1032                 goto done;
 1033 
 1034         /* Cases in which we need to copyout */
 1035         switch (uap->cmd) {
 1036         case IPC_STAT:
 1037                 ipcperm_new2old(&buf.shm_perm, &old.shm_perm);
 1038                 if (buf.shm_segsz > INT_MAX)
 1039                         old.shm_segsz = INT_MAX;
 1040                 else
 1041                         CP(buf, old, shm_segsz);
 1042                 CP(buf, old, shm_lpid);
 1043                 CP(buf, old, shm_cpid);
 1044                 if (buf.shm_nattch > SHRT_MAX)
 1045                         old.shm_nattch = SHRT_MAX;
 1046                 else
 1047                         CP(buf, old, shm_nattch);
 1048                 CP(buf, old, shm_atime);
 1049                 CP(buf, old, shm_dtime);
 1050                 CP(buf, old, shm_ctime);
 1051                 old.shm_internal = NULL;
 1052                 error = copyout(&old, uap->buf, sizeof(old));
 1053                 break;
 1054         }
 1055 
 1056 done:
 1057         if (error) {
 1058                 /* Invalidate the return value */
 1059                 td->td_retval[0] = -1;
 1060         }
 1061         return (error);
 1062 }
 1063 
 1064 SYSCALL_MODULE_HELPER(freebsd7_shmctl);
 1065 
 1066 #undef CP
 1067 
 1068 #endif  /* COMPAT_FREEBSD4 || COMPAT_FREEBSD5 || COMPAT_FREEBSD6 ||
 1069            COMPAT_FREEBSD7 */
 1070 
 1071 static int
 1072 sysvshm_modload(struct module *module, int cmd, void *arg)
 1073 {
 1074         int error = 0;
 1075 
 1076         switch (cmd) {
 1077         case MOD_LOAD:
 1078                 shminit();
 1079                 break;
 1080         case MOD_UNLOAD:
 1081                 error = shmunload();
 1082                 break;
 1083         case MOD_SHUTDOWN:
 1084                 break;
 1085         default:
 1086                 error = EINVAL;
 1087                 break;
 1088         }
 1089         return (error);
 1090 }
 1091 
 1092 static moduledata_t sysvshm_mod = {
 1093         "sysvshm",
 1094         &sysvshm_modload,
 1095         NULL
 1096 };
 1097 
 1098 SYSCALL_MODULE_HELPER(shmat);
 1099 SYSCALL_MODULE_HELPER(shmctl);
 1100 SYSCALL_MODULE_HELPER(shmdt);
 1101 SYSCALL_MODULE_HELPER(shmget);
 1102 
 1103 DECLARE_MODULE(sysvshm, sysvshm_mod, SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
 1104 MODULE_VERSION(sysvshm, 1);

Cache object: 0726066a479b729e00db93934e3b1f60


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.