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freebsd-skq/sys/kern/sysv_shm.c
Edward Tomasz Napierala 92001b9497 Change the default setting of kern.ipc.shm_allow_removed from 0 to 1. 
This removes the need for manually changing this flag for Google Chrome
users. It also improves compatibility with Linux applications running under
Linuxulator compatibility layer, and possibly also helps in porting software
from Linux.

Generally speaking, the flag allows applications to create the shared memory
segment, attach it, remove it, and then continue to use it and to reattach it
later. This means that the kernel will automatically "clean up" after the
application exits.

It could be argued that it's against POSIX. However, SUSv3 says this
about IPC_RMID: "Remove the shared memory identifier specified by shmid from
the system and destroy the shared memory segment and shmid_ds data structure
associated with it." From my reading, we break it in any case by deferring
removal of the segment until it's detached; we won't break it any more
by also deferring removal of the identifier.

This is the behaviour exhibited by Linux since... probably always, and
also by OpenBSD since the following commit:

revision 1.54
date: 2011/10/27 07:56:28; author: robert; state: Exp; lines: +3 -8;
Allow segments to be used even after they were marked for deletion with
the IPC_RMID flag.
This is permitted as an extension beyond the standards and this is similar
to what other operating systems like linux do.

MFC after:	1 month
Relnotes:	yes
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D3603
2015-10-10 09:29:47 +00:00

1365 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/rwlock.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
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(int, bool);
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 = SHMMAX,
.shmmin = SHMMIN,
.shmmni = SHMMNI,
.shmseg = SHMSEG,
.shmall = SHMALL
};
static int shm_use_phys;
static int shm_allow_removed = 1;
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RWTUN, &shminfo.shmmax, 0,
"Maximum shared memory segment size");
SYSCTL_ULONG(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RWTUN, &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_RWTUN, &shminfo.shmall, 0,
"Maximum number of pages available for shared memory");
SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RWTUN,
&shm_use_phys, 0, "Enable/Disable locking of shared memory pages in core");
SYSCTL_INT(_kern_ipc, OID_AUTO, shm_allow_removed, CTLFLAG_RWTUN,
&shm_allow_removed, 0,
"Enable/Disable attachment to attached segments marked for removal");
SYSCTL_PROC(_kern_ipc, OID_AUTO, shmsegs, CTLTYPE_OPAQUE | CTLFLAG_RD |
CTLFLAG_MPSAFE, NULL, 0, sysctl_shmsegs, "",
"Current number of shared memory segments allocated");
static struct sx sysvshmsx;
#define SYSVSHM_LOCK() sx_xlock(&sysvshmsx)
#define SYSVSHM_UNLOCK() sx_xunlock(&sysvshmsx)
#define SYSVSHM_ASSERT_LOCKED() sx_assert(&sysvshmsx, SA_XLOCKED)
static int
shm_find_segment_by_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);
}
/*
* Finds segment either by shmid if is_shmid is true, or by segnum if
* is_shmid is false.
*/
static struct shmid_kernel *
shm_find_segment(int arg, bool is_shmid)
{
struct shmid_kernel *shmseg;
int segnum;
segnum = is_shmid ? IPCID_TO_IX(arg) : arg;
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) ||
(is_shmid && shmseg->u.shm_perm.seq != IPCID_TO_SEQ(arg)))
return (NULL);
return (shmseg);
}
static void
shm_deallocate_segment(struct shmid_kernel *shmseg)
{
vm_size_t size;
SYSVSHM_ASSERT_LOCKED();
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;
SYSVSHM_ASSERT_LOCKED();
segnum = IPCID_TO_IX(shmmap_s->shmid);
KASSERT(segnum >= 0 && segnum < shmalloced,
("segnum %d shmalloced %d", segnum, shmalloced));
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);
}
static int
kern_shmdt_locked(struct thread *td, const void *shmaddr)
{
struct proc *p = td->td_proc;
struct shmmap_state *shmmap_s;
#ifdef MAC
struct shmid_kernel *shmsegptr;
int error;
#endif
int i;
SYSVSHM_ASSERT_LOCKED();
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
shmmap_s = p->p_vmspace->vm_shm;
if (shmmap_s == NULL)
return (EINVAL);
for (i = 0; i < shminfo.shmseg; i++, shmmap_s++) {
if (shmmap_s->shmid != -1 &&
shmmap_s->va == (vm_offset_t)shmaddr) {
break;
}
}
if (i == shminfo.shmseg)
return (EINVAL);
#ifdef MAC
shmsegptr = &shmsegs[IPCID_TO_IX(shmmap_s->shmid)];
error = mac_sysvshm_check_shmdt(td->td_ucred, shmsegptr);
if (error != 0)
return (error);
#endif
return (shm_delete_mapping(p->p_vmspace, shmmap_s));
}
#ifndef _SYS_SYSPROTO_H_
struct shmdt_args {
const void *shmaddr;
};
#endif
int
sys_shmdt(struct thread *td, struct shmdt_args *uap)
{
int error;
SYSVSHM_LOCK();
error = kern_shmdt_locked(td, uap->shmaddr);
SYSVSHM_UNLOCK();
return (error);
}
static int
kern_shmat_locked(struct thread *td, int shmid, const void *shmaddr,
int shmflg)
{
struct proc *p = td->td_proc;
struct shmid_kernel *shmseg;
struct shmmap_state *shmmap_s;
vm_offset_t attach_va;
vm_prot_t prot;
vm_size_t size;
int error, i, rv;
SYSVSHM_ASSERT_LOCKED();
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
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;
KASSERT(p->p_vmspace->vm_shm == NULL, ("raced"));
p->p_vmspace->vm_shm = shmmap_s;
}
shmseg = shm_find_segment(shmid, true);
if (shmseg == NULL)
return (EINVAL);
error = ipcperm(td, &shmseg->u.shm_perm,
(shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
if (error != 0)
return (error);
#ifdef MAC
error = mac_sysvshm_check_shmat(td->td_ucred, shmseg, shmflg);
if (error != 0)
return (error);
#endif
for (i = 0; i < shminfo.shmseg; i++) {
if (shmmap_s->shmid == -1)
break;
shmmap_s++;
}
if (i >= shminfo.shmseg)
return (EMFILE);
size = round_page(shmseg->u.shm_segsz);
prot = VM_PROT_READ;
if ((shmflg & SHM_RDONLY) == 0)
prot |= VM_PROT_WRITE;
if (shmaddr != NULL) {
if ((shmflg & SHM_RND) != 0)
attach_va = (vm_offset_t)shmaddr & ~(SHMLBA-1);
else if (((vm_offset_t)shmaddr & (SHMLBA-1)) == 0)
attach_va = (vm_offset_t)shmaddr;
else
return (EINVAL);
} else {
/*
* This is just a hint to vm_map_find() about where to
* put it.
*/
attach_va = round_page((vm_offset_t)p->p_vmspace->vm_daddr +
lim_max(td, RLIMIT_DATA));
}
vm_object_reference(shmseg->object);
rv = vm_map_find(&p->p_vmspace->vm_map, shmseg->object, 0, &attach_va,
size, 0, shmaddr != NULL ? VMFS_NO_SPACE : VMFS_OPTIMAL_SPACE,
prot, prot, MAP_INHERIT_SHARE | MAP_PREFAULT_PARTIAL);
if (rv != KERN_SUCCESS) {
vm_object_deallocate(shmseg->object);
return (ENOMEM);
}
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;
return (error);
}
int
kern_shmat(struct thread *td, int shmid, const void *shmaddr, int shmflg)
{
int error;
SYSVSHM_LOCK();
error = kern_shmat_locked(td, shmid, shmaddr, shmflg);
SYSVSHM_UNLOCK();
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct shmat_args {
int shmid;
const void *shmaddr;
int shmflg;
};
#endif
int
sys_shmat(struct thread *td, struct shmat_args *uap)
{
return (kern_shmat(td, uap->shmid, uap->shmaddr, uap->shmflg));
}
static int
kern_shmctl_locked(struct thread *td, int shmid, int cmd, void *buf,
size_t *bufsz)
{
struct shmid_kernel *shmseg;
struct shmid_ds *shmidp;
struct shm_info shm_info;
int error;
SYSVSHM_ASSERT_LOCKED();
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
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;
return (0);
case 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 != NULL)
*bufsz = sizeof(shm_info);
td->td_retval[0] = shmalloced;
return (0);
}
}
shmseg = shm_find_segment(shmid, cmd != SHM_STAT);
if (shmseg == NULL)
return (EINVAL);
#ifdef MAC
error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, cmd);
if (error != 0)
return (error);
#endif
switch (cmd) {
case SHM_STAT:
case IPC_STAT:
error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
if (error != 0)
return (error);
memcpy(buf, &shmseg->u, sizeof(struct shmid_ds));
if (bufsz != NULL)
*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:
shmidp = (struct shmid_ds *)buf;
error = ipcperm(td, &shmseg->u.shm_perm, IPC_M);
if (error != 0)
return (error);
shmseg->u.shm_perm.uid = shmidp->shm_perm.uid;
shmseg->u.shm_perm.gid = shmidp->shm_perm.gid;
shmseg->u.shm_perm.mode =
(shmseg->u.shm_perm.mode & ~ACCESSPERMS) |
(shmidp->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 != 0)
return (error);
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;
}
return (error);
}
int
kern_shmctl(struct thread *td, int shmid, int cmd, void *buf, size_t *bufsz)
{
int error;
SYSVSHM_LOCK();
error = kern_shmctl_locked(td, shmid, cmd, buf, bufsz);
SYSVSHM_UNLOCK();
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct shmctl_args {
int shmid;
int cmd;
struct shmid_ds *buf;
};
#endif
int
sys_shmctl(struct thread *td, struct shmctl_args *uap)
{
int error;
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(struct thread *td, struct shmget_args *uap, int mode,
int segnum)
{
struct shmid_kernel *shmseg;
#ifdef MAC
int error;
#endif
SYSVSHM_ASSERT_LOCKED();
KASSERT(segnum >= 0 && segnum < shmalloced,
("segnum %d shmalloced %d", segnum, shmalloced));
shmseg = &shmsegs[segnum];
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(struct thread *td, struct shmget_args *uap, int mode)
{
struct ucred *cred = td->td_ucred;
struct shmid_kernel *shmseg;
vm_object_t shm_object;
int i, segnum;
size_t size;
SYSVSHM_ASSERT_LOCKED();
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;
}
KASSERT(segnum >= 0 && segnum < shmalloced,
("segnum %d shmalloced %d", segnum, shmalloced));
shmseg = &shmsegs[segnum];
#ifdef RACCT
if (racct_enable) {
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
/*
* 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
if (racct_enable) {
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);
}
shm_object->pg_color = 0;
VM_OBJECT_WLOCK(shm_object);
vm_object_clear_flag(shm_object, OBJ_ONEMAPPING);
vm_object_set_flag(shm_object, OBJ_COLORED | OBJ_NOSPLIT);
VM_OBJECT_WUNLOCK(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 = (mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
shmseg->u.shm_perm.key = uap->key;
shmseg->u.shm_perm.seq = (shmseg->u.shm_perm.seq + 1) & 0x7fff;
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++;
td->td_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->u.shm_perm);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct shmget_args {
key_t key;
size_t size;
int shmflg;
};
#endif
int
sys_shmget(struct thread *td, struct shmget_args *uap)
{
int segnum, mode;
int error;
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
mode = uap->shmflg & ACCESSPERMS;
SYSVSHM_LOCK();
if (uap->key == IPC_PRIVATE) {
error = shmget_allocate_segment(td, uap, mode);
} else {
segnum = shm_find_segment_by_key(uap->key);
if (segnum >= 0)
error = shmget_existing(td, uap, mode, segnum);
else if ((uap->shmflg & IPC_CREAT) == 0)
error = ENOENT;
else
error = shmget_allocate_segment(td, uap, mode);
}
SYSVSHM_UNLOCK();
return (error);
}
static void
shmfork_myhook(struct proc *p1, struct proc *p2)
{
struct shmmap_state *shmmap_s;
size_t size;
int i;
SYSVSHM_LOCK();
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) {
KASSERT(IPCID_TO_IX(shmmap_s->shmid) >= 0 &&
IPCID_TO_IX(shmmap_s->shmid) < shmalloced,
("segnum %d shmalloced %d",
IPCID_TO_IX(shmmap_s->shmid), shmalloced));
shmsegs[IPCID_TO_IX(shmmap_s->shmid)].u.shm_nattch++;
}
}
SYSVSHM_UNLOCK();
}
static void
shmexit_myhook(struct vmspace *vm)
{
struct shmmap_state *base, *shm;
int i;
base = vm->vm_shm;
if (base != NULL) {
vm->vm_shm = NULL;
SYSVSHM_LOCK();
for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) {
if (shm->shmid != -1)
shm_delete_mapping(vm, shm);
}
SYSVSHM_UNLOCK();
free(base, M_SHM);
}
}
static void
shmrealloc(void)
{
struct shmid_kernel *newsegs;
int i;
SYSVSHM_ASSERT_LOCKED();
if (shmalloced >= shminfo.shmmni)
return;
newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK);
for (i = 0; i < shmalloced; i++)
bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0]));
for (; i < shminfo.shmmni; i++) {
newsegs[i].u.shm_perm.mode = SHMSEG_FREE;
newsegs[i].u.shm_perm.seq = 0;
#ifdef MAC
mac_sysvshm_init(&newsegs[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(void)
{
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
if (shminfo.shmmax == SHMMAX) {
/* Initialize shmmax dealing with possible overflow. */
for (i = PAGE_SIZE; i != 0; i--) {
shminfo.shmmax = shminfo.shmall * i;
if ((shminfo.shmmax / shminfo.shmall) == (u_long)i)
break;
}
}
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;
sx_init(&sysvshmsx, "sysvshmsx");
shmexit_hook = &shmexit_myhook;
shmfork_hook = &shmfork_myhook;
error = syscall_helper_register(shm_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
error = syscall32_helper_register(shm32_syscalls, SY_THR_STATIC_KLD);
if (error != 0)
return (error);
#endif
return (0);
}
static int
shmunload(void)
{
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;
sx_destroy(&sysvshmsx);
return (0);
}
static int
sysctl_shmsegs(SYSCTL_HANDLER_ARGS)
{
int error;
SYSVSHM_LOCK();
error = SYSCTL_OUT(req, shmsegs, shmalloced * sizeof(shmsegs[0]));
SYSVSHM_UNLOCK();
return (error);
}
#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);
if (uap->cmd != IPC_STAT) {
return (freebsd7_shmctl(td,
(struct freebsd7_shmctl_args *)uap));
}
SYSVSHM_LOCK();
shmseg = shm_find_segment(uap->shmid, true);
if (shmseg == NULL) {
SYSVSHM_UNLOCK();
return (EINVAL);
}
error = ipcperm(td, &shmseg->u.shm_perm, IPC_R);
if (error != 0) {
SYSVSHM_UNLOCK();
return (error);
}
#ifdef MAC
error = mac_sysvshm_check_shmctl(td->td_ucred, shmseg, uap->cmd);
if (error != 0) {
SYSVSHM_UNLOCK();
return (error);
}
#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;
SYSVSHM_UNLOCK();
return (copyout(&outbuf, uap->ubuf, sizeof(outbuf)));
#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
};
#ifndef _SYS_SYSPROTO_H_
/* XXX actually varargs. */
struct shmsys_args {
int which;
int a2;
int a3;
int a4;
};
#endif
int
sys_shmsys(struct thread *td, struct shmsys_args *uap)
{
if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
return (ENOSYS);
if (uap->which < 0 || uap->which >= nitems(shmcalls))
return (EINVAL);
return ((*shmcalls[uap->which])(td, &uap->a2));
}
#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;
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;
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(struct thread *td, struct freebsd7_shmctl_args *uap)
{
int error;
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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