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freebsd/sys/kern/sysv_shm.c
1999-04-27 12:21:16 +00:00

614 lines
16 KiB
C

/* $Id: sysv_shm.c,v 1.40 1999/01/21 08:29:04 dillon Exp $ */
/* $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.
*/
#include "opt_compat.h"
#include "opt_rlimit.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/shm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/sysent.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/vm_prot.h>
#include <sys/lock.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>
#include <vm/vm_inherit.h>
#ifndef _SYS_SYSPROTO_H_
struct shmat_args;
extern int shmat __P((struct proc *p, struct shmat_args *uap));
struct shmctl_args;
extern int shmctl __P((struct proc *p, struct shmctl_args *uap));
struct shmdt_args;
extern int shmdt __P((struct proc *p, struct shmdt_args *uap));
struct shmget_args;
extern int shmget __P((struct proc *p, struct shmget_args *uap));
#endif
static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments");
static void shminit __P((void *));
SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL)
struct oshmctl_args;
static int oshmctl __P((struct proc *p, struct oshmctl_args *uap));
static int shmget_allocate_segment __P((struct proc *p, struct shmget_args *uap, int mode));
static int shmget_existing __P((struct proc *p, struct shmget_args *uap, int mode, int segnum));
/* XXX casting to (sy_call_t *) is bogus, as usual. */
static sy_call_t *shmcalls[] = {
(sy_call_t *)shmat, (sy_call_t *)oshmctl,
(sy_call_t *)shmdt, (sy_call_t *)shmget,
(sy_call_t *)shmctl
};
#define SHMSEG_FREE 0x0200
#define SHMSEG_REMOVED 0x0400
#define SHMSEG_ALLOCATED 0x0800
#define SHMSEG_WANTED 0x1000
static int shm_last_free, shm_nused, shm_committed;
struct shmid_ds *shmsegs;
struct shm_handle {
/* vm_offset_t kva; */
vm_object_t shm_object;
};
struct shmmap_state {
vm_offset_t va;
int shmid;
};
static void shm_deallocate_segment __P((struct shmid_ds *));
static int shm_find_segment_by_key __P((key_t));
static struct shmid_ds *shm_find_segment_by_shmid __P((int));
static int shm_delete_mapping __P((struct proc *, struct shmmap_state *));
static int
shm_find_segment_by_key(key)
key_t key;
{
int i;
for (i = 0; i < shminfo.shmmni; i++)
if ((shmsegs[i].shm_perm.mode & SHMSEG_ALLOCATED) &&
shmsegs[i].shm_perm.key == key)
return i;
return -1;
}
static struct shmid_ds *
shm_find_segment_by_shmid(shmid)
int shmid;
{
int segnum;
struct shmid_ds *shmseg;
segnum = IPCID_TO_IX(shmid);
if (segnum < 0 || segnum >= shminfo.shmmni)
return NULL;
shmseg = &shmsegs[segnum];
if ((shmseg->shm_perm.mode & (SHMSEG_ALLOCATED | SHMSEG_REMOVED))
!= SHMSEG_ALLOCATED ||
shmseg->shm_perm.seq != IPCID_TO_SEQ(shmid))
return NULL;
return shmseg;
}
static void
shm_deallocate_segment(shmseg)
struct shmid_ds *shmseg;
{
struct shm_handle *shm_handle;
size_t size;
shm_handle = shmseg->shm_internal;
vm_object_deallocate(shm_handle->shm_object);
free((caddr_t)shm_handle, M_SHM);
shmseg->shm_internal = NULL;
size = round_page(shmseg->shm_segsz);
shm_committed -= btoc(size);
shm_nused--;
shmseg->shm_perm.mode = SHMSEG_FREE;
}
static int
shm_delete_mapping(p, shmmap_s)
struct proc *p;
struct shmmap_state *shmmap_s;
{
struct shmid_ds *shmseg;
int segnum, result;
size_t size;
segnum = IPCID_TO_IX(shmmap_s->shmid);
shmseg = &shmsegs[segnum];
size = round_page(shmseg->shm_segsz);
result = vm_map_remove(&p->p_vmspace->vm_map, shmmap_s->va, shmmap_s->va + size);
if (result != KERN_SUCCESS)
return EINVAL;
shmmap_s->shmid = -1;
shmseg->shm_dtime = time_second;
if ((--shmseg->shm_nattch <= 0) &&
(shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
shm_deallocate_segment(shmseg);
shm_last_free = segnum;
}
return 0;
}
#ifndef _SYS_SYSPROTO_H_
struct shmdt_args {
void *shmaddr;
};
#endif
int
shmdt(p, uap)
struct proc *p;
struct shmdt_args *uap;
{
struct shmmap_state *shmmap_s;
int i;
shmmap_s = (struct shmmap_state *)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)uap->shmaddr)
break;
if (i == shminfo.shmseg)
return EINVAL;
return shm_delete_mapping(p, shmmap_s);
}
#ifndef _SYS_SYSPROTO_H_
struct shmat_args {
int shmid;
void *shmaddr;
int shmflg;
};
#endif
int
shmat(p, uap)
struct proc *p;
struct shmat_args *uap;
{
int error, i, flags;
struct shmid_ds *shmseg;
struct shmmap_state *shmmap_s = NULL;
struct shm_handle *shm_handle;
vm_offset_t attach_va;
vm_prot_t prot;
vm_size_t size;
int rv;
shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
if (shmmap_s == NULL) {
size = shminfo.shmseg * sizeof(struct shmmap_state);
shmmap_s = malloc(size, M_SHM, M_WAITOK);
for (i = 0; i < shminfo.shmseg; i++)
shmmap_s[i].shmid = -1;
p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
}
shmseg = shm_find_segment_by_shmid(uap->shmid);
if (shmseg == NULL)
return EINVAL;
error = ipcperm(p, &shmseg->shm_perm,
(uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W);
if (error)
return error;
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->shm_segsz);
prot = VM_PROT_READ;
if ((uap->shmflg & SHM_RDONLY) == 0)
prot |= VM_PROT_WRITE;
flags = MAP_ANON | MAP_SHARED;
if (uap->shmaddr) {
flags |= MAP_FIXED;
if (uap->shmflg & SHM_RND)
attach_va = (vm_offset_t)uap->shmaddr & ~(SHMLBA-1);
else if (((vm_offset_t)uap->shmaddr & (SHMLBA-1)) == 0)
attach_va = (vm_offset_t)uap->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_taddr + MAXTSIZ + MAXDSIZ);
}
shm_handle = shmseg->shm_internal;
vm_object_reference(shm_handle->shm_object);
rv = vm_map_find(&p->p_vmspace->vm_map, shm_handle->shm_object,
0, &attach_va, size, (flags & MAP_FIXED)?0:1, prot, prot, 0);
if (rv != KERN_SUCCESS) {
return ENOMEM;
}
vm_map_inherit(&p->p_vmspace->vm_map,
attach_va, attach_va + size, VM_INHERIT_SHARE);
shmmap_s->va = attach_va;
shmmap_s->shmid = uap->shmid;
shmseg->shm_lpid = p->p_pid;
shmseg->shm_atime = time_second;
shmseg->shm_nattch++;
p->p_retval[0] = attach_va;
return 0;
}
struct oshmid_ds {
struct ipc_perm shm_perm; /* operation perms */
int shm_segsz; /* size of segment (bytes) */
ushort shm_cpid; /* pid, creator */
ushort 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(p, uap)
struct proc *p;
struct oshmctl_args *uap;
{
#ifdef COMPAT_43
int error;
struct shmid_ds *shmseg;
struct oshmid_ds outbuf;
shmseg = shm_find_segment_by_shmid(uap->shmid);
if (shmseg == NULL)
return EINVAL;
switch (uap->cmd) {
case IPC_STAT:
error = ipcperm(p, &shmseg->shm_perm, IPC_R);
if (error)
return error;
outbuf.shm_perm = shmseg->shm_perm;
outbuf.shm_segsz = shmseg->shm_segsz;
outbuf.shm_cpid = shmseg->shm_cpid;
outbuf.shm_lpid = shmseg->shm_lpid;
outbuf.shm_nattch = shmseg->shm_nattch;
outbuf.shm_atime = shmseg->shm_atime;
outbuf.shm_dtime = shmseg->shm_dtime;
outbuf.shm_ctime = shmseg->shm_ctime;
outbuf.shm_handle = shmseg->shm_internal;
error = copyout((caddr_t)&outbuf, uap->ubuf, sizeof(outbuf));
if (error)
return error;
break;
default:
/* XXX casting to (sy_call_t *) is bogus, as usual. */
return ((sy_call_t *)shmctl)(p, uap);
}
return 0;
#else
return EINVAL;
#endif
}
#ifndef _SYS_SYSPROTO_H_
struct shmctl_args {
int shmid;
int cmd;
struct shmid_ds *buf;
};
#endif
int
shmctl(p, uap)
struct proc *p;
struct shmctl_args *uap;
{
int error;
struct shmid_ds inbuf;
struct shmid_ds *shmseg;
shmseg = shm_find_segment_by_shmid(uap->shmid);
if (shmseg == NULL)
return EINVAL;
switch (uap->cmd) {
case IPC_STAT:
error = ipcperm(p, &shmseg->shm_perm, IPC_R);
if (error)
return error;
error = copyout((caddr_t)shmseg, uap->buf, sizeof(inbuf));
if (error)
return error;
break;
case IPC_SET:
error = ipcperm(p, &shmseg->shm_perm, IPC_M);
if (error)
return error;
error = copyin(uap->buf, (caddr_t)&inbuf, sizeof(inbuf));
if (error)
return error;
shmseg->shm_perm.uid = inbuf.shm_perm.uid;
shmseg->shm_perm.gid = inbuf.shm_perm.gid;
shmseg->shm_perm.mode =
(shmseg->shm_perm.mode & ~ACCESSPERMS) |
(inbuf.shm_perm.mode & ACCESSPERMS);
shmseg->shm_ctime = time_second;
break;
case IPC_RMID:
error = ipcperm(p, &shmseg->shm_perm, IPC_M);
if (error)
return error;
shmseg->shm_perm.key = IPC_PRIVATE;
shmseg->shm_perm.mode |= SHMSEG_REMOVED;
if (shmseg->shm_nattch <= 0) {
shm_deallocate_segment(shmseg);
shm_last_free = IPCID_TO_IX(uap->shmid);
}
break;
#if 0
case SHM_LOCK:
case SHM_UNLOCK:
#endif
default:
return EINVAL;
}
return 0;
}
#ifndef _SYS_SYSPROTO_H_
struct shmget_args {
key_t key;
size_t size;
int shmflg;
};
#endif
static int
shmget_existing(p, uap, mode, segnum)
struct proc *p;
struct shmget_args *uap;
int mode;
int segnum;
{
struct shmid_ds *shmseg;
int error;
shmseg = &shmsegs[segnum];
if (shmseg->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->shm_perm.mode |= SHMSEG_WANTED;
error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
if (error)
return error;
return EAGAIN;
}
error = ipcperm(p, &shmseg->shm_perm, mode);
if (error)
return error;
if (uap->size && uap->size > shmseg->shm_segsz)
return EINVAL;
if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL))
return EEXIST;
p->p_retval[0] = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
return 0;
}
static int
shmget_allocate_segment(p, uap, mode)
struct proc *p;
struct shmget_args *uap;
int mode;
{
int i, segnum, shmid, size;
struct ucred *cred = p->p_ucred;
struct shmid_ds *shmseg;
struct shm_handle *shm_handle;
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) {
for (i = 0; i < shminfo.shmmni; i++)
if (shmsegs[i].shm_perm.mode & SHMSEG_FREE)
break;
if (i == shminfo.shmmni)
panic("shmseg free count inconsistent");
segnum = i;
} else {
segnum = shm_last_free;
shm_last_free = -1;
}
shmseg = &shmsegs[segnum];
/*
* In case we sleep in malloc(), mark the segment present but deleted
* so that noone else tries to create the same key.
*/
shmseg->shm_perm.mode = SHMSEG_ALLOCATED | SHMSEG_REMOVED;
shmseg->shm_perm.key = uap->key;
shmseg->shm_perm.seq = (shmseg->shm_perm.seq + 1) & 0x7fff;
shm_handle = (struct shm_handle *)
malloc(sizeof(struct shm_handle), M_SHM, M_WAITOK);
shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
/*
* We make sure that we have allocated a pager before we need
* to.
*/
shm_handle->shm_object =
vm_pager_allocate(OBJT_SWAP, 0, size, VM_PROT_DEFAULT, 0);
vm_object_clear_flag(shm_handle->shm_object, OBJ_ONEMAPPING);
vm_object_set_flag(shm_handle->shm_object, OBJ_NOSPLIT);
shmseg->shm_internal = shm_handle;
shmseg->shm_perm.cuid = shmseg->shm_perm.uid = cred->cr_uid;
shmseg->shm_perm.cgid = shmseg->shm_perm.gid = cred->cr_gid;
shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) |
(mode & ACCESSPERMS) | SHMSEG_ALLOCATED;
shmseg->shm_segsz = uap->size;
shmseg->shm_cpid = p->p_pid;
shmseg->shm_lpid = shmseg->shm_nattch = 0;
shmseg->shm_atime = shmseg->shm_dtime = 0;
shmseg->shm_ctime = time_second;
shm_committed += btoc(size);
shm_nused++;
if (shmseg->shm_perm.mode & SHMSEG_WANTED) {
/*
* Somebody else wanted this key while we were asleep. Wake
* them up now.
*/
shmseg->shm_perm.mode &= ~SHMSEG_WANTED;
wakeup((caddr_t)shmseg);
}
p->p_retval[0] = shmid;
return 0;
}
int
shmget(p, uap)
struct proc *p;
struct shmget_args *uap;
{
int segnum, mode, error;
mode = uap->shmflg & ACCESSPERMS;
if (uap->key != IPC_PRIVATE) {
again:
segnum = shm_find_segment_by_key(uap->key);
if (segnum >= 0) {
error = shmget_existing(p, uap, mode, segnum);
if (error == EAGAIN)
goto again;
return error;
}
if ((uap->shmflg & IPC_CREAT) == 0)
return ENOENT;
}
return shmget_allocate_segment(p, uap, mode);
}
int
shmsys(p, uap)
struct proc *p;
/* XXX actually varargs. */
struct shmsys_args /* {
u_int which;
int a2;
int a3;
int a4;
} */ *uap;
{
if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
return EINVAL;
return ((*shmcalls[uap->which])(p, &uap->a2));
}
void
shmfork(p1, p2)
struct proc *p1, *p2;
{
struct shmmap_state *shmmap_s;
size_t size;
int i;
size = shminfo.shmseg * sizeof(struct shmmap_state);
shmmap_s = malloc(size, M_SHM, M_WAITOK);
bcopy((caddr_t)p1->p_vmspace->vm_shm, (caddr_t)shmmap_s, size);
p2->p_vmspace->vm_shm = (caddr_t)shmmap_s;
for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
if (shmmap_s->shmid != -1)
shmsegs[IPCID_TO_IX(shmmap_s->shmid)].shm_nattch++;
}
void
shmexit(p)
struct proc *p;
{
struct shmmap_state *shmmap_s;
int i;
shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm;
for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
if (shmmap_s->shmid != -1)
shm_delete_mapping(p, shmmap_s);
free((caddr_t)p->p_vmspace->vm_shm, M_SHM);
p->p_vmspace->vm_shm = NULL;
}
void
shminit(dummy)
void *dummy;
{
int i;
for (i = 0; i < shminfo.shmmni; i++) {
shmsegs[i].shm_perm.mode = SHMSEG_FREE;
shmsegs[i].shm_perm.seq = 0;
}
shm_last_free = 0;
shm_nused = 0;
shm_committed = 0;
}