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freebsd-dev/sys/kern/sysv_shm.c
Alan Cox 7dc0ace10e Close a race due to dropping of the map lock between creating a map entry 
for a shared mapping and marking the entry for inheritance.

Reviewed by:	kib
X-MFC after:	r231526
2012-02-19 00:28:49 +00:00

1407 lines
36 KiB
C
Raw Blame History

/* $NetBSD: sysv_shm.c,v 1.23 1994/07/04 23:25:12 glass Exp $ */
/*-
* Copyright (c) 1994 Adam Glass and Charles Hannum. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Adam Glass and Charles
* Hannum.
* 4. The names of the authors may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*-
* Copyright (c) 2003-2005 McAfee, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project in part by McAfee
* Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
* contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
* program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include "opt_sysvipc.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/shm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/racct.h>
#include <sys/resourcevar.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/syscallsubr.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/jail.h>
#include <security/mac/mac_framework.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_object.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
FEATURE(sysv_shm, "System V shared memory segments support");
static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
static int shmget_allocate_segment(struct thread *td,
struct shmget_args *uap, int mode);
static int shmget_existing(struct thread *td, struct shmget_args *uap,
int mode, int segnum);
#define SHMSEG_FREE 0x0200
#define SHMSEG_REMOVED 0x0400
#define SHMSEG_ALLOCATED 0x0800
#define SHMSEG_WANTED 0x1000
static int shm_last_free, shm_nused, shmalloced;
vm_size_t shm_committed;
static struct shmid_kernel *shmsegs;
struct shmmap_state {
vm_offset_t va;
int shmid;
};
static void shm_deallocate_segment(struct shmid_kernel *);
static int shm_find_segment_by_key(key_t);
static struct shmid_kernel *shm_find_segment_by_shmid(int);
static struct shmid_kernel *shm_find_segment_by_shmidx(int);
static int shm_delete_mapping(struct vmspace *vm, struct shmmap_state *);
static void shmrealloc(void);
static int shminit(void);
static int sysvshm_modload(struct module *, int, void *);
static int shmunload(void);
static void shmexit_myhook(struct vmspace *vm);
static void shmfork_myhook(struct proc *p1, struct proc *p2);
static int sysctl_shmsegs(SYSCTL_HANDLER_ARGS);
/*
* Tuneable values.
*/
#ifndef SHMMAXPGS
#define SHMMAXPGS 131072 /* Note: sysv shared memory is swap backed. */
#endif
#ifndef SHMMAX
#define SHMMAX (SHMMAXPGS*PAGE_SIZE)
#endif
#ifndef SHMMIN
#define SHMMIN 1
#endif
#ifndef SHMMNI
#define SHMMNI 192
#endif
#ifndef SHMSEG
#define SHMSEG 128
#endif
#ifndef SHMALL
#define SHMALL (SHMMAXPGS)
#endif
struct shminfo shminfo = {
SHMMAX,
SHMMIN,
SHMMNI,
SHMSEG,
SHMALL
};
static int shm_use_phys;
static int shm_allow_removed;
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0,
"Maximum shared memory segment size");
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0,
"Minimum shared memory segment size");
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RDTUN, &shminfo.shmmni, 0,
"Number of shared memory identifiers");
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RDTUN, &shminfo.shmseg, 0,
"Number of segments per process");
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0,
"Maximum number of pages available for shared memory");
SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW,
&shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RW,
&shm_allow_removed, 0,
"Enable/Disable attachment to attached segments marked for removal");
SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLTYPE_OPAQUE | CTLFLAG_RD,
NULL, 0, sysctl_shmsegs, "",
"Current number of shared memory segments allocated");
static int
shm_find_segment_by_key(key)
key_t key;
{
int i;
for (i = 0; i < shmalloced; i++)
if ((shmsegs[i].u.shm_perm.mode & SHMSEG_ALLOCATED) &&
shmsegs[i].u.shm_perm.key == key)
return (i);
return (-1);
}
static struct shmid_kernel *
shm_find_segment_by_shmid(int shmid)
{
int segnum;
struct shmid_kernel *shmseg;
segnum = IPCID_TO_IX(shmid);
if (segnum < 0 || segnum >= shmalloced)
return (NULL);
shmseg = &shmsegs[segnum];
if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
(!shm_allow_removed &&
(shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0) ||
shmseg->u.shm_perm.seq != IPCID_TO_SEQ(shmid))
return (NULL);
return (shmseg);
}
static struct shmid_kernel *
shm_find_segment_by_shmidx(int segnum)
{
struct shmid_kernel *shmseg;
if (segnum < 0 || segnum >= shmalloced)
return (NULL);
shmseg = &shmsegs[segnum];
if ((shmseg->u.shm_perm.mode & SHMSEG_ALLOCATED) == 0 ||
(!shm_allow_removed &&
(shmseg->u.shm_perm.mode & SHMSEG_REMOVED) != 0))
return (NULL);
return (shmseg);
}
static void
shm_deallocate_segment(shmseg)
struct shmid_kernel *shmseg;
{
vm_size_t size;
GIANT_REQUIRED;
vm_object_deallocate(shmseg->object);
shmseg->object = NULL;
size = round_page(shmseg->u.shm_segsz);
shm_committed -= btoc(size);
shm_nused--;
shmseg->u.shm_perm.mode = SHMSEG_FREE;
#ifdef MAC
mac_sysvshm_cleanup(shmseg);
#endif
racct_sub_cred(shmseg->cred, RACCT_NSHM, 1);
racct_sub_cred(shmseg->cred, RACCT_SHMSIZE, size);
crfree(shmseg->cred);
shmseg->cred = NULL;
}
static int
shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s)
{
struct shmid_kernel *shmseg;
int segnum, result;
vm_size_t size;
GIANT_REQUIRED;
segnum = IPCID_TO_IX(shmmap_s->shmid);
shmseg = &shmsegs[segnum];
size = round_page(shmseg->u.shm_segsz);
result = vm_map_remove(&vm->vm_map, shmmap_s->va, shmmap_s->va + size);
if (result != KERN_SUCCESS)
return (EINVAL);
shmmap_s->shmid = -1;
shmseg->u.shm_dtime = time_second;
if ((--shmseg->u.shm_nattch <= 0) &&
(shmseg->u.shm_perm.mode & SHMSEG_REMOVED)) {
shm_deallocate_segment(shmseg);
shm_last_free = segnum;
}
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct shmdt_args {
const void *shmaddr;
};
#endif
int
sys_shmdt(td, uap)
struct thread *td;
struct shmdt_args *uap;
{
struct proc *p = td->td_proc;
struct shmmap_state *shmmap_s;
#ifdef MAC
struct shmid_kernel *shmsegptr;
#endif
int i;
int error = 0;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
mtx_lock(&Giant);
shmmap_s = p->p_vmspace->vm_shm;
if (shmmap_s == NULL) {
error = EINVAL;
goto done2;
}
for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
if (shmmap_s->shmid != -1 &&
shmmap_s->va == (vm_offset_t)uap->shmaddr) {
break;
}
}
if (i == shminfo.shmseg) {
error = EINVAL;
goto done2;
}
#ifdef MAC
shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)];
error = mac_sysvshm_check_shmdt(td->td_ucred, shmsegptr);
if (error != 0)
goto done2;
#endif
error = shm_delete_mapping(p->p_vmspace, shmmap_s);
done2:
mtx_unlock(&Giant);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct shmat_args {
int shmid;
const void *shmaddr;
int shmflg;
};
#endif
int
kern_shmat(td, shmid, shmaddr, shmflg)
struct thread *td;
int shmid;
const void *shmaddr;
int shmflg;
{
struct proc *p = td->td_proc;
int i, flags;
struct shmid_kernel *shmseg;
struct shmmap_state *shmmap_s = NULL;
vm_offset_t attach_va;
vm_prot_t prot;
vm_size_t size;
int rv;
int error = 0;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
mtx_lock(&Giant);
shmmap_s = p->p_vmspace->vm_shm;
if (shmmap_s == NULL) {
shmmap_s = malloc(shminfo.shmseg * sizeof(struct shmmap_state),
M_SHM, M_WAITOK);
for (i = 0; i < shminfo.shmseg; i++)
shmmap_s[i].shmid = -1;
p->p_vmspace->vm_shm = shmmap_s;
}
shmseg = shm_find_segment_by_shmid(shmid);
if (shmseg == NULL) {
error = EINVAL;
goto done2;
}
error = ipcperm(td, &shmseg->u.shm_perm,
(shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
if (error)
goto done2;
#ifdef MAC
error = mac_sysvshm_check_shmat(td->td_ucred, shmseg, shmflg);
if (error != 0)
goto done2;
#endif
for (i = 0; i < shminfo.shmseg; i++) {
if (shmmap_s->shmid == -1)
break;
shmmap_s++;
}
if (i >= shminfo.shmseg) {
error = EMFILE;
goto done2;
}
size = round_page(shmseg->u.shm_segsz);
prot = VM_PROT_READ;
if ((shmflg & SHM_RDONLY) == 0)
prot |= VM_PROT_WRITE;
flags = MAP_ANON | MAP_SHARED;
if (shmaddr) {
flags |= MAP_FIXED;
if (shmflg & SHM_RND) {
attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
} else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0) {
attach_va = (vm_offset_t)shmaddr;
} else {
error = EINVAL;
goto done2;
}
} else {
/*
* This is just a hint to vm_map_find() about where to
* put it.
*/
PROC_LOCK(p);
attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
lim_max(p, RLIMIT_DATA));
PROC_UNLOCK(p);
}
vm_object_reference(shmseg->object);
rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->object,
0, &attach_va, size, (flags & MAP_FIXED) ? VMFS_NO_SPACE :
VMFS_ANY_SPACE, prot, prot, MAP_INHERIT_SHARE);
if (rv != KERN_SUCCESS) {
vm_object_deallocate(shmseg->object);
error = ENOMEM;
goto done2;
}
shmmap_s->va = attach_va;
shmmap_s->shmid = shmid;
shmseg->u.shm_lpid = p->p_pid;
shmseg->u.shm_atime = time_second;
shmseg->u.shm_nattch++;
td->td_retval[0] = attach_va;
done2:
mtx_unlock(&Giant);
return (error);
}
int
sys_shmat(td, uap)
struct thread *td;
struct shmat_args *uap;
{
return kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg);
}
int
kern_shmctl(td, shmid, cmd, buf, bufsz)
struct thread *td;
int shmid;
int cmd;
void *buf;
size_t *bufsz;
{
int error = 0;
struct shmid_kernel *shmseg;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
mtx_lock(&Giant);
switch (cmd) {
/*
* It is possible that kern_shmctl is being called from the Linux ABI
* layer, in which case, we will need to implement IPC_INFO. It should
* be noted that other shmctl calls will be funneled through here for
* Linix binaries as well.
*
* NB: The Linux ABI layer will convert this data to structure(s) more
* consistent with the Linux ABI.
*/
case IPC_INFO:
memcpy(buf, &shminfo, sizeof(shminfo));
if (bufsz)
*bufsz = sizeof(shminfo);
td->td_retval[0] = shmalloced;
goto done2;
case SHM_INFO: {
struct shm_info shm_info;
shm_info.used_ids = shm_nused;
shm_info.shm_rss = 0; /*XXX where to get from ? */
shm_info.shm_tot = 0; /*XXX where to get from ? */
shm_info.shm_swp = 0; /*XXX where to get from ? */
shm_info.swap_attempts = 0; /*XXX where to get from ? */
shm_info.swap_successes = 0; /*XXX where to get from ? */
memcpy(buf, &shm_info, sizeof(shm_info));
if (bufsz)
*bufsz = sizeof(shm_info);
td->td_retval[0] = shmalloced;
goto done2;
}
}
if (cmd == SHM_STAT)
shmseg = shm_find_segment_by_shmidx(shmid);
else
shmseg = shm_find_segment_by_shmid(shmid);
if (shmseg == NULL) {
error = EINVAL;
goto done2;
}
#ifdef MAC
error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd);
if (error != 0)
goto done2;
#endif
switch (cmd) {
case SHM_STAT:
case IPC_STAT:
error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
if (error)
goto done2;
memcpy(buf, &shmseg->u, sizeof(struct shmid_ds));
if (bufsz)
*bufsz = sizeof(struct shmid_ds);
if (cmd == SHM_STAT)
td->td_retval[0] = IXSEQ_TO_IPCID(shmid, shmseg->u.shm_perm);
break;
case IPC_SET: {
struct shmid_ds *shmid;
shmid = (struct shmid_ds *)buf;
error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
if (error)
goto done2;
shmseg->u.shm_perm.uid = shmid->shm_perm.uid;
shmseg->u.shm_perm.gid = shmid->shm_perm.gid;
shmseg->u.shm_perm.mode =
(shmseg->u.shm_perm.mode & ~ACCESSPERMS) |
(shmid->shm_perm.mode & ACCESSPERMS);
shmseg->u.shm_ctime = time_second;
break;
}
case IPC_RMID:
error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
if (error)
goto done2;
shmseg->u.shm_perm.key = IPC_PRIVATE;
shmseg->u.shm_perm.mode |= SHMSEG_REMOVED;
if (shmseg->u.shm_nattch <= 0) {
shm_deallocate_segment(shmseg);
shm_last_free = IPCID_TO_IX(shmid);
}
break;
#if 0
case SHM_LOCK:
case SHM_UNLOCK:
#endif
default:
error = EINVAL;
break;
}
done2:
mtx_unlock(&Giant);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct shmctl_args {
int shmid;
int cmd;
struct shmid_ds *buf;
};
#endif
int
sys_shmctl(td, uap)
struct thread *td;
struct shmctl_args *uap;
{
int error = 0;
struct shmid_ds buf;
size_t bufsz;
/*
* The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support
* Linux binaries. If we see the call come through the FreeBSD ABI,
* return an error back to the user since we do not to support this.
*/
if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO ||
uap->cmd == SHM_STAT)
return (EINVAL);
/* IPC_SET needs to copyin the buffer before calling kern_shmctl */
if (uap->cmd == IPC_SET) {
if ((error = copyin(uap->buf, &buf, sizeof(struct shmid_ds))))
goto done;
}
error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
if (error)
goto done;
/* Cases in which we need to copyout */
switch (uap->cmd) {
case IPC_STAT:
error = copyout(&buf, uap->buf, bufsz);
break;
}
done:
if (error) {
/* Invalidate the return value */
td->td_retval[0] = -1;
}
return (error);
}
static int
shmget_existing(td, uap, mode, segnum)
struct thread *td;
struct shmget_args *uap;
int mode;
int segnum;
{
struct shmid_kernel *shmseg;
int error;
shmseg = &shmsegs[segnum];
if (shmseg->u.shm_perm.mode & SHMSEG_REMOVED) {
/*
* This segment is in the process of being allocated. Wait
* until it's done, and look the key up again (in case the
* allocation failed or it was freed).
*/
shmseg->u.shm_perm.mode |= SHMSEG_WANTED;
error = tsleep(shmseg, PLOCK | PCATCH, "shmget", 0);
if (error)
return (error);
return (EAGAIN);
}
if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
return (EEXIST);
#ifdef MAC
error = mac_sysvshm_check_shmget(td->td_ucred, shmseg, uap->shmflg);
if (error != 0)
return (error);
#endif
if (uap->size != 0 && uap->size > shmseg->u.shm_segsz)
return (EINVAL);
td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
return (0);
}
static int
shmget_allocate_segment(td, uap, mode)
struct thread *td;
struct shmget_args *uap;
int mode;
{
int i, segnum, shmid;
size_t size;
struct ucred *cred = td->td_ucred;
struct shmid_kernel *shmseg;
vm_object_t shm_object;
GIANT_REQUIRED;
if (uap->size < shminfo.shmmin || uap->size > shminfo.shmmax)
return (EINVAL);
if (shm_nused >= shminfo.shmmni) /* Any shmids left? */
return (ENOSPC);
size = round_page(uap->size);
if (shm_committed + btoc(size) > shminfo.shmall)
return (ENOMEM);
if (shm_last_free < 0) {
shmrealloc(); /* Maybe expand the shmsegs[] array. */
for (i = 0; i < shmalloced; i++)
if (shmsegs[i].u.shm_perm.mode & SHMSEG_FREE)
break;
if (i == shmalloced)
return (ENOSPC);
segnum = i;
} else {
segnum = shm_last_free;
shm_last_free = -1;
}
shmseg = &shmsegs[segnum];
#ifdef RACCT
PROC_LOCK(td->td_proc);
if (racct_add(td->td_proc, RACCT_NSHM, 1)) {
PROC_UNLOCK(td->td_proc);
return (ENOSPC);
}
if (racct_add(td->td_proc, RACCT_SHMSIZE, size)) {
racct_sub(td->td_proc, RACCT_NSHM, 1);
PROC_UNLOCK(td->td_proc);
return (ENOMEM);
}
PROC_UNLOCK(td->td_proc);
#endif
/*
* In case we sleep in malloc(), mark the segment present but deleted
* so that noone else tries to create the same key.
*/
shmseg->u.shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
shmseg->u.shm_perm.key = uap->key;
shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff;
shmid = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
/*
* We make sure that we have allocated a pager before we need
* to.
*/
shm_object = vm_pager_allocate(shm_use_phys ? OBJT_PHYS : OBJT_SWAP,
0, size, VM_PROT_DEFAULT, 0, cred);
if (shm_object == NULL) {
#ifdef RACCT
PROC_LOCK(td->td_proc);
racct_sub(td->td_proc, RACCT_NSHM, 1);
racct_sub(td->td_proc, RACCT_SHMSIZE, size);
PROC_UNLOCK(td->td_proc);
#endif
return (ENOMEM);
}
VM_OBJECT_LOCK(shm_object);
vm_object_clear_flag(shm_object, OBJ_ONEMAPPING);
vm_object_set_flag(shm_object, OBJ_NOSPLIT);
VM_OBJECT_UNLOCK(shm_object);
shmseg->object = shm_object;
shmseg->u.shm_perm.cuid = shmseg->u.shm_perm.uid = cred->cr_uid;
shmseg->u.shm_perm.cgid = shmseg->u.shm_perm.gid = cred->cr_gid;
shmseg->u.shm_perm.mode = (shmseg->u.shm_perm.mode & SHMSEG_WANTED) |
(mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
shmseg->cred = crhold(cred);
shmseg->u.shm_segsz = uap->size;
shmseg->u.shm_cpid = td->td_proc->p_pid;
shmseg->u.shm_lpid = shmseg->u.shm_nattch = 0;
shmseg->u.shm_atime = shmseg->u.shm_dtime = 0;
#ifdef MAC
mac_sysvshm_create(cred, shmseg);
#endif
shmseg->u.shm_ctime = time_second;
shm_committed += btoc(size);
shm_nused++;
if (shmseg->u.shm_perm.mode & SHMSEG_WANTED) {
/*
* Somebody else wanted this key while we were asleep. Wake
* them up now.
*/
shmseg->u.shm_perm.mode &= ~SHMSEG_WANTED;
wakeup(shmseg);
}
td->td_retval[0] = shmid;
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct shmget_args {
key_t key;
size_t size;
int shmflg;
};
#endif
int
sys_shmget(td, uap)
struct thread *td;
struct shmget_args *uap;
{
int segnum, mode;
int error;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
mtx_lock(&Giant);
mode = uap->shmflg & ACCESSPERMS;
if (uap->key != IPC_PRIVATE) {
again:
segnum = shm_find_segment_by_key(uap->key);
if (segnum >= 0) {
error = shmget_existing(td, uap, mode, segnum);
if (error == EAGAIN)
goto again;
goto done2;
}
if ((uap->shmflg & IPC_CREAT) == 0) {
error = ENOENT;
goto done2;
}
}
error = shmget_allocate_segment(td, uap, mode);
done2:
mtx_unlock(&Giant);
return (error);
}
static void
shmfork_myhook(p1, p2)
struct proc *p1, *p2;
{
struct shmmap_state *shmmap_s;
size_t size;
int i;
mtx_lock(&Giant);
size = shminfo.shmseg * sizeof(struct shmmap_state);
shmmap_s = malloc(size, M_SHM, M_WAITOK);
bcopy(p1->p_vmspace->vm_shm, shmmap_s, size);
p2->p_vmspace->vm_shm = shmmap_s;
for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
if (shmmap_s->shmid != -1)
shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++;
mtx_unlock(&Giant);
}
static void
shmexit_myhook(struct vmspace *vm)
{
struct shmmap_state *base, *shm;
int i;
if ((base = vm->vm_shm) != NULL) {
vm->vm_shm = NULL;
mtx_lock(&Giant);
for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
if (shm->shmid != -1)
shm_delete_mapping(vm, shm);
}
mtx_unlock(&Giant);
free(base, M_SHM);
}
}
static void
shmrealloc(void)
{
int i;
struct shmid_kernel *newsegs;
if (shmalloced >= shminfo.shmmni)
return;
newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
if (newsegs == NULL)
return;
for (i = 0; i < shmalloced; i++)
bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
for (; i < shminfo.shmmni; i++) {
shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
shmsegs[i].u.shm_perm.seq = 0;
#ifdef MAC
mac_sysvshm_init(&shmsegs[i]);
#endif
}
free(shmsegs, M_SHM);
shmsegs = newsegs;
shmalloced = shminfo.shmmni;
}
static struct syscall_helper_data shm_syscalls[] = {
SYSCALL_INIT_HELPER(shmat),
SYSCALL_INIT_HELPER(shmctl),
SYSCALL_INIT_HELPER(shmdt),
SYSCALL_INIT_HELPER(shmget),
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
SYSCALL_INIT_HELPER_COMPAT(freebsd7_shmctl),
#endif
#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43))
SYSCALL_INIT_HELPER(shmsys),
#endif
SYSCALL_INIT_LAST
};
#ifdef COMPAT_FREEBSD32
#include <compat/freebsd32/freebsd32.h>
#include <compat/freebsd32/freebsd32_ipc.h>
#include <compat/freebsd32/freebsd32_proto.h>
#include <compat/freebsd32/freebsd32_signal.h>
#include <compat/freebsd32/freebsd32_syscall.h>
#include <compat/freebsd32/freebsd32_util.h>
static struct syscall_helper_data shm32_syscalls[] = {
SYSCALL32_INIT_HELPER_COMPAT(shmat),
SYSCALL32_INIT_HELPER_COMPAT(shmdt),
SYSCALL32_INIT_HELPER_COMPAT(shmget),
SYSCALL32_INIT_HELPER(freebsd32_shmsys),
SYSCALL32_INIT_HELPER(freebsd32_shmctl),
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
SYSCALL32_INIT_HELPER(freebsd7_freebsd32_shmctl),
#endif
SYSCALL_INIT_LAST
};
#endif
static int
shminit()
{
int i, error;
#ifndef BURN_BRIDGES
if (TUNABLE_ULONG_FETCH("kern.ipc.shmmaxpgs", &shminfo.shmall) != 0)
printf("kern.ipc.shmmaxpgs is now called kern.ipc.shmall!\n");
#endif
TUNABLE_ULONG_FETCH("kern.ipc.shmall", &shminfo.shmall);
if (!TUNABLE_ULONG_FETCH("kern.ipc.shmmax", &shminfo.shmmax)) {
/* Initialize shmmax dealing with possible overflow. */
for (i = PAGE_SIZE; i > 0; i--) {
shminfo.shmmax = shminfo.shmall * i;
if (shminfo.shmmax >= shminfo.shmall)
break;
}
}
TUNABLE_ULONG_FETCH("kern.ipc.shmmin", &shminfo.shmmin);
TUNABLE_ULONG_FETCH("kern.ipc.shmmni", &shminfo.shmmni);
TUNABLE_ULONG_FETCH("kern.ipc.shmseg", &shminfo.shmseg);
TUNABLE_INT_FETCH("kern.ipc.shm_use_phys", &shm_use_phys);
shmalloced = shminfo.shmmni;
shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK);
for (i = 0; i < shmalloced; i++) {
shmsegs[i].u.shm_perm.mode = SHMSEG_FREE;
shmsegs[i].u.shm_perm.seq = 0;
#ifdef MAC
mac_sysvshm_init(&shmsegs[i]);
#endif
}
shm_last_free = 0;
shm_nused = 0;
shm_committed = 0;
shmexit_hook = &shmexit_myhook;
shmfork_hook = &shmfork_myhook;
error = syscall_helper_register(shm_syscalls);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(shm32_syscalls);
if (error != 0)
return (error);
#endif
return (0);
}
static int
shmunload()
{
int i;
if (shm_nused > 0)
return (EBUSY);
#ifdef COMPAT_FREEBSD32
syscall32_helper_unregister(shm32_syscalls);
#endif
syscall_helper_unregister(shm_syscalls);
for (i = 0; i < shmalloced; i++) {
#ifdef MAC
mac_sysvshm_destroy(&shmsegs[i]);
#endif
/*
* Objects might be still mapped into the processes
* address spaces. Actual free would happen on the
* last mapping destruction.
*/
if (shmsegs[i].u.shm_perm.mode != SHMSEG_FREE)
vm_object_deallocate(shmsegs[i].object);
}
free(shmsegs, M_SHM);
shmexit_hook = NULL;
shmfork_hook = NULL;
return (0);
}
static int
sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
{
return (SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0])));
}
#if defined(__i386__) && (defined(COMPAT_FREEBSD4) || defined(COMPAT_43))
struct oshmid_ds {
struct ipc_perm_old shm_perm; /* operation perms */
int shm_segsz; /* size of segment (bytes) */
u_short shm_cpid; /* pid, creator */
u_short shm_lpid; /* pid, last operation */
short shm_nattch; /* no. of current attaches */
time_t shm_atime; /* last attach time */
time_t shm_dtime; /* last detach time */
time_t shm_ctime; /* last change time */
void *shm_handle; /* internal handle for shm segment */
};
struct oshmctl_args {
int shmid;
int cmd;
struct oshmid_ds *ubuf;
};
static int
oshmctl(struct thread *td, struct oshmctl_args *uap)
{
#ifdef COMPAT_43
int error = 0;
struct shmid_kernel *shmseg;
struct oshmid_ds outbuf;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
mtx_lock(&Giant);
shmseg = shm_find_segment_by_shmid(uap->shmid);
if (shmseg == NULL) {
error = EINVAL;
goto done2;
}
switch (uap->cmd) {
case IPC_STAT:
error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
if (error)
goto done2;
#ifdef MAC
error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd);
if (error != 0)
goto done2;
#endif
ipcperm_new2old(&shmseg->u.shm_perm, &outbuf.shm_perm);
outbuf.shm_segsz = shmseg->u.shm_segsz;
outbuf.shm_cpid = shmseg->u.shm_cpid;
outbuf.shm_lpid = shmseg->u.shm_lpid;
outbuf.shm_nattch = shmseg->u.shm_nattch;
outbuf.shm_atime = shmseg->u.shm_atime;
outbuf.shm_dtime = shmseg->u.shm_dtime;
outbuf.shm_ctime = shmseg->u.shm_ctime;
outbuf.shm_handle = shmseg->object;
error = copyout(&outbuf, uap->ubuf, sizeof(outbuf));
if (error)
goto done2;
break;
default:
error = freebsd7_shmctl(td, (struct freebsd7_shmctl_args *)uap);
break;
}
done2:
mtx_unlock(&Giant);
return (error);
#else
return (EINVAL);
#endif
}
/* XXX casting to (sy_call_t *) is bogus, as usual. */
static sy_call_t *shmcalls[] = {
(sy_call_t *)sys_shmat, (sy_call_t *)oshmctl,
(sy_call_t *)sys_shmdt, (sy_call_t *)sys_shmget,
(sy_call_t *)freebsd7_shmctl
};
int
sys_shmsys(td, uap)
struct thread *td;
/* XXX actually varargs. */
struct shmsys_args /* {
int which;
int a2;
int a3;
int a4;
} */ *uap;
{
int error;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
if (uap->which < 0 ||
uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
return (EINVAL);
mtx_lock(&Giant);
error = (*shmcalls[uap->which])(td, &uap->a2);
mtx_unlock(&Giant);
return (error);
}
#endif /* i386 && (COMPAT_FREEBSD4 || COMPAT_43) */
#ifdef COMPAT_FREEBSD32
int
freebsd32_shmsys(struct thread *td, struct freebsd32_shmsys_args *uap)
{
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
switch (uap->which) {
case 0: { /* shmat */
struct shmat_args ap;
ap.shmid = uap->a2;
ap.shmaddr = PTRIN(uap->a3);
ap.shmflg = uap->a4;
return (sysent[SYS_shmat].sy_call(td, &ap));
}
case 2: { /* shmdt */
struct shmdt_args ap;
ap.shmaddr = PTRIN(uap->a2);
return (sysent[SYS_shmdt].sy_call(td, &ap));
}
case 3: { /* shmget */
struct shmget_args ap;
ap.key = uap->a2;
ap.size = uap->a3;
ap.shmflg = uap->a4;
return (sysent[SYS_shmget].sy_call(td, &ap));
}
case 4: { /* shmctl */
struct freebsd7_freebsd32_shmctl_args ap;
ap.shmid = uap->a2;
ap.cmd = uap->a3;
ap.buf = PTRIN(uap->a4);
return (freebsd7_freebsd32_shmctl(td, &ap));
}
case 1: /* oshmctl */
default:
return (EINVAL);
}
#else
return (nosys(td, NULL));
#endif
}
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
int
freebsd7_freebsd32_shmctl(struct thread *td,
struct freebsd7_freebsd32_shmctl_args *uap)
{
int error = 0;
union {
struct shmid_ds shmid_ds;
struct shm_info shm_info;
struct shminfo shminfo;
} u;
union {
struct shmid_ds32_old shmid_ds32;
struct shm_info32 shm_info32;
struct shminfo32 shminfo32;
} u32;
size_t sz;
if (uap->cmd == IPC_SET) {
if ((error = copyin(uap->buf, &u32.shmid_ds32,
sizeof(u32.shmid_ds32))))
goto done;
freebsd32_ipcperm_old_in(&u32.shmid_ds32.shm_perm,
&u.shmid_ds.shm_perm);
CP(u32.shmid_ds32, u.shmid_ds, shm_segsz);
CP(u32.shmid_ds32, u.shmid_ds, shm_lpid);
CP(u32.shmid_ds32, u.shmid_ds, shm_cpid);
CP(u32.shmid_ds32, u.shmid_ds, shm_nattch);
CP(u32.shmid_ds32, u.shmid_ds, shm_atime);
CP(u32.shmid_ds32, u.shmid_ds, shm_dtime);
CP(u32.shmid_ds32, u.shmid_ds, shm_ctime);
}
error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&u, &sz);
if (error)
goto done;
/* Cases in which we need to copyout */
switch (uap->cmd) {
case IPC_INFO:
CP(u.shminfo, u32.shminfo32, shmmax);
CP(u.shminfo, u32.shminfo32, shmmin);
CP(u.shminfo, u32.shminfo32, shmmni);
CP(u.shminfo, u32.shminfo32, shmseg);
CP(u.shminfo, u32.shminfo32, shmall);
error = copyout(&u32.shminfo32, uap->buf,
sizeof(u32.shminfo32));
break;
case SHM_INFO:
CP(u.shm_info, u32.shm_info32, used_ids);
CP(u.shm_info, u32.shm_info32, shm_rss);
CP(u.shm_info, u32.shm_info32, shm_tot);
CP(u.shm_info, u32.shm_info32, shm_swp);
CP(u.shm_info, u32.shm_info32, swap_attempts);
CP(u.shm_info, u32.shm_info32, swap_successes);
error = copyout(&u32.shm_info32, uap->buf,
sizeof(u32.shm_info32));
break;
case SHM_STAT:
case IPC_STAT:
freebsd32_ipcperm_old_out(&u.shmid_ds.shm_perm,
&u32.shmid_ds32.shm_perm);
if (u.shmid_ds.shm_segsz > INT32_MAX)
u32.shmid_ds32.shm_segsz = INT32_MAX;
else
CP(u.shmid_ds, u32.shmid_ds32, shm_segsz);
CP(u.shmid_ds, u32.shmid_ds32, shm_lpid);
CP(u.shmid_ds, u32.shmid_ds32, shm_cpid);
CP(u.shmid_ds, u32.shmid_ds32, shm_nattch);
CP(u.shmid_ds, u32.shmid_ds32, shm_atime);
CP(u.shmid_ds, u32.shmid_ds32, shm_dtime);
CP(u.shmid_ds, u32.shmid_ds32, shm_ctime);
u32.shmid_ds32.shm_internal = 0;
error = copyout(&u32.shmid_ds32, uap->buf,
sizeof(u32.shmid_ds32));
break;
}
done:
if (error) {
/* Invalidate the return value */
td->td_retval[0] = -1;
}
return (error);
}
#endif
int
freebsd32_shmctl(struct thread *td, struct freebsd32_shmctl_args *uap)
{
int error = 0;
union {
struct shmid_ds shmid_ds;
struct shm_info shm_info;
struct shminfo shminfo;
} u;
union {
struct shmid_ds32 shmid_ds32;
struct shm_info32 shm_info32;
struct shminfo32 shminfo32;
} u32;
size_t sz;
if (uap->cmd == IPC_SET) {
if ((error = copyin(uap->buf, &u32.shmid_ds32,
sizeof(u32.shmid_ds32))))
goto done;
freebsd32_ipcperm_in(&u32.shmid_ds32.shm_perm,
&u.shmid_ds.shm_perm);
CP(u32.shmid_ds32, u.shmid_ds, shm_segsz);
CP(u32.shmid_ds32, u.shmid_ds, shm_lpid);
CP(u32.shmid_ds32, u.shmid_ds, shm_cpid);
CP(u32.shmid_ds32, u.shmid_ds, shm_nattch);
CP(u32.shmid_ds32, u.shmid_ds, shm_atime);
CP(u32.shmid_ds32, u.shmid_ds, shm_dtime);
CP(u32.shmid_ds32, u.shmid_ds, shm_ctime);
}
error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&u, &sz);
if (error)
goto done;
/* Cases in which we need to copyout */
switch (uap->cmd) {
case IPC_INFO:
CP(u.shminfo, u32.shminfo32, shmmax);
CP(u.shminfo, u32.shminfo32, shmmin);
CP(u.shminfo, u32.shminfo32, shmmni);
CP(u.shminfo, u32.shminfo32, shmseg);
CP(u.shminfo, u32.shminfo32, shmall);
error = copyout(&u32.shminfo32, uap->buf,
sizeof(u32.shminfo32));
break;
case SHM_INFO:
CP(u.shm_info, u32.shm_info32, used_ids);
CP(u.shm_info, u32.shm_info32, shm_rss);
CP(u.shm_info, u32.shm_info32, shm_tot);
CP(u.shm_info, u32.shm_info32, shm_swp);
CP(u.shm_info, u32.shm_info32, swap_attempts);
CP(u.shm_info, u32.shm_info32, swap_successes);
error = copyout(&u32.shm_info32, uap->buf,
sizeof(u32.shm_info32));
break;
case SHM_STAT:
case IPC_STAT:
freebsd32_ipcperm_out(&u.shmid_ds.shm_perm,
&u32.shmid_ds32.shm_perm);
if (u.shmid_ds.shm_segsz > INT32_MAX)
u32.shmid_ds32.shm_segsz = INT32_MAX;
else
CP(u.shmid_ds, u32.shmid_ds32, shm_segsz);
CP(u.shmid_ds, u32.shmid_ds32, shm_lpid);
CP(u.shmid_ds, u32.shmid_ds32, shm_cpid);
CP(u.shmid_ds, u32.shmid_ds32, shm_nattch);
CP(u.shmid_ds, u32.shmid_ds32, shm_atime);
CP(u.shmid_ds, u32.shmid_ds32, shm_dtime);
CP(u.shmid_ds, u32.shmid_ds32, shm_ctime);
error = copyout(&u32.shmid_ds32, uap->buf,
sizeof(u32.shmid_ds32));
break;
}
done:
if (error) {
/* Invalidate the return value */
td->td_retval[0] = -1;
}
return (error);
}
#endif
#if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
#ifndef CP
#define CP(src, dst, fld) do { (dst).fld = (src).fld; } while (0)
#endif
#ifndef _SYS_SYSPROTO_H_
struct freebsd7_shmctl_args {
int shmid;
int cmd;
struct shmid_ds_old *buf;
};
#endif
int
freebsd7_shmctl(td, uap)
struct thread *td;
struct freebsd7_shmctl_args *uap;
{
int error = 0;
struct shmid_ds_old old;
struct shmid_ds buf;
size_t bufsz;
/*
* The only reason IPC_INFO, SHM_INFO, SHM_STAT exists is to support
* Linux binaries. If we see the call come through the FreeBSD ABI,
* return an error back to the user since we do not to support this.
*/
if (uap->cmd == IPC_INFO || uap->cmd == SHM_INFO ||
uap->cmd == SHM_STAT)
return (EINVAL);
/* IPC_SET needs to copyin the buffer before calling kern_shmctl */
if (uap->cmd == IPC_SET) {
if ((error = copyin(uap->buf, &old, sizeof(old))))
goto done;
ipcperm_old2new(&old.shm_perm, &buf.shm_perm);
CP(old, buf, shm_segsz);
CP(old, buf, shm_lpid);
CP(old, buf, shm_cpid);
CP(old, buf, shm_nattch);
CP(old, buf, shm_atime);
CP(old, buf, shm_dtime);
CP(old, buf, shm_ctime);
}
error = kern_shmctl(td, uap->shmid, uap->cmd, (void *)&buf, &bufsz);
if (error)
goto done;
/* Cases in which we need to copyout */
switch (uap->cmd) {
case IPC_STAT:
ipcperm_new2old(&buf.shm_perm, &old.shm_perm);
if (buf.shm_segsz > INT_MAX)
old.shm_segsz = INT_MAX;
else
CP(buf, old, shm_segsz);
CP(buf, old, shm_lpid);
CP(buf, old, shm_cpid);
if (buf.shm_nattch > SHRT_MAX)
old.shm_nattch = SHRT_MAX;
else
CP(buf, old, shm_nattch);
CP(buf, old, shm_atime);
CP(buf, old, shm_dtime);
CP(buf, old, shm_ctime);
old.shm_internal = NULL;
error = copyout(&old, uap->buf, sizeof(old));
break;
}
done:
if (error) {
/* Invalidate the return value */
td->td_retval[0] = -1;
}
return (error);
}
#endif /* COMPAT_FREEBSD4 || COMPAT_FREEBSD5 || COMPAT_FREEBSD6 ||
COMPAT_FREEBSD7 */
static int
sysvshm_modload(struct module *module, int cmd, void *arg)
{
int error = 0;
switch (cmd) {
case MOD_LOAD:
error = shminit();
if (error != 0)
shmunload();
break;
case MOD_UNLOAD:
error = shmunload();
break;
case MOD_SHUTDOWN:
break;
default:
error = EINVAL;
break;
}
return (error);
}
static moduledata_t sysvshm_mod = {
"sysvshm",
&sysvshm_modload,
NULL
};
DECLARE_MODULE(sysvshm, sysvshm_mod, SI_SUB_SYSV_SHM, SI_ORDER_FIRST);
MODULE_VERSION(sysvshm, 1);
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