NetBSD/sys/kern/sysv_shm.c

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/* $NetBSD: sysv_shm.c,v 1.48 1998/08/15 03:02:49 mycroft Exp $ */
/*
* Copyright (c) 1994 Adam Glass and Charles M. 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.
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* 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 M.
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* 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.
*
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* 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_uvm.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/shm.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <sys/time.h>
#include <sys/malloc.h>
#include <sys/mman.h>
#include <sys/systm.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <vm/vm.h>
#ifdef UVM
#include <uvm/uvm_extern.h>
#else
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#endif
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struct shmid_ds *shm_find_segment_by_shmid __P((int));
/*
* Provides the following externally accessible functions:
*
* shminit(void); initialization
* shmexit(struct vmspace *) cleanup
* shmfork(struct vmspace *, struct vmspace *) fork handling
* shmsys(arg1, arg2, arg3, arg4); shm{at,ctl,dt,get}(arg2, arg3, arg4)
*
* Structures:
* shmsegs (an array of 'struct shmid_ds')
* per proc array of 'struct shmmap_state'
*/
#define SHMSEG_FREE 0x0200
#define SHMSEG_REMOVED 0x0400
#define SHMSEG_ALLOCATED 0x0800
#define SHMSEG_WANTED 0x1000
int shm_last_free, shm_nused, shm_committed;
struct shm_handle {
#ifdef UVM
struct uvm_object *shm_object;
#else
vm_object_t shm_object;
#endif
};
struct shmmap_state {
vaddr_t va;
int shmid;
};
static int shm_find_segment_by_key __P((key_t));
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static void shm_deallocate_segment __P((struct shmid_ds *));
static int shm_delete_mapping __P((struct vmspace *, struct shmmap_state *));
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static int shmget_existing __P((struct proc *, struct sys_shmget_args *,
int, int, register_t *));
static int shmget_allocate_segment __P((struct proc *, struct sys_shmget_args *,
int, register_t *));
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;
}
struct shmid_ds *
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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;
size = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET;
#ifdef UVM
uao_detach(shm_handle->shm_object);
#else
vm_object_deallocate(shm_handle->shm_object);
#endif
free((caddr_t)shm_handle, M_SHM);
shmseg->shm_internal = NULL;
shm_committed -= btoc(size);
shmseg->shm_perm.mode = SHMSEG_FREE;
shm_nused--;
}
static int
shm_delete_mapping(vm, shmmap_s)
struct vmspace *vm;
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 = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET;
#ifdef UVM
result = uvm_deallocate(&vm->vm_map, shmmap_s->va, size);
#else
result = vm_map_remove(&vm->vm_map,
shmmap_s->va, shmmap_s->va + size);
#endif
if (result != KERN_SUCCESS)
return EINVAL;
shmmap_s->shmid = -1;
shmseg->shm_dtime = time.tv_sec;
if ((--shmseg->shm_nattch <= 0) &&
(shmseg->shm_perm.mode & SHMSEG_REMOVED)) {
shm_deallocate_segment(shmseg);
shm_last_free = segnum;
}
return 0;
}
int
sys_shmdt(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_shmdt_args /* {
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syscallarg(const void *) shmaddr;
} */ *uap = v;
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 == (vaddr_t)SCARG(uap, shmaddr))
break;
if (i == shminfo.shmseg)
return EINVAL;
return shm_delete_mapping(p->p_vmspace, shmmap_s);
}
int
sys_shmat(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_shmat_args /* {
syscallarg(int) shmid;
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syscallarg(const void *) shmaddr;
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syscallarg(int) shmflg;
} */ *uap = v;
int error, i, flags;
struct ucred *cred = p->p_ucred;
struct shmid_ds *shmseg;
struct shmmap_state *shmmap_s = NULL;
struct shm_handle *shm_handle;
vaddr_t attach_va;
vm_prot_t prot;
vsize_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);
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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(SCARG(uap, shmid));
if (shmseg == NULL)
return EINVAL;
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error = ipcperm(cred, &shmseg->shm_perm,
(SCARG(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 = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET;
prot = VM_PROT_READ;
if ((SCARG(uap, shmflg) & SHM_RDONLY) == 0)
prot |= VM_PROT_WRITE;
flags = MAP_ANON | MAP_SHARED;
if (SCARG(uap, shmaddr)) {
flags |= MAP_FIXED;
if (SCARG(uap, shmflg) & SHM_RND)
attach_va =
(vaddr_t)SCARG(uap, shmaddr) & ~(SHMLBA-1);
else if (((vaddr_t)SCARG(uap, shmaddr) & (SHMLBA-1)) == 0)
attach_va = (vaddr_t)SCARG(uap, shmaddr);
else
return EINVAL;
} else {
/* This is just a hint to vm_mmap() about where to put it. */
attach_va =
round_page(p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ);
}
shm_handle = shmseg->shm_internal;
#ifdef UVM
uao_reference(shm_handle->shm_object);
rv = uvm_map(&p->p_vmspace->vm_map, &attach_va, size,
shm_handle->shm_object, 0,
UVM_MAPFLAG(prot, prot, UVM_INH_SHARE,
UVM_ADV_RANDOM, 0));
if (rv != KERN_SUCCESS) {
return ENOMEM;
}
#else
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);
if (rv != KERN_SUCCESS) {
return ENOMEM;
}
vm_map_protect(&p->p_vmspace->vm_map, attach_va, attach_va + size,
prot, 0);
vm_map_inherit(&p->p_vmspace->vm_map,
attach_va, attach_va + size, VM_INHERIT_SHARE);
#endif
shmmap_s->va = attach_va;
shmmap_s->shmid = SCARG(uap, shmid);
shmseg->shm_lpid = p->p_pid;
shmseg->shm_atime = time.tv_sec;
shmseg->shm_nattch++;
*retval = attach_va;
return 0;
}
int
sys_shmctl(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_shmctl_args /* {
syscallarg(int) shmid;
syscallarg(int) cmd;
syscallarg(struct shmid_ds *) buf;
} */ *uap = v;
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int error;
struct ucred *cred = p->p_ucred;
struct shmid_ds inbuf;
struct shmid_ds *shmseg;
shmseg = shm_find_segment_by_shmid(SCARG(uap, shmid));
if (shmseg == NULL)
return EINVAL;
switch (SCARG(uap, cmd)) {
case IPC_STAT:
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if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0)
return error;
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error = copyout((caddr_t)shmseg, SCARG(uap, buf),
sizeof(inbuf));
if (error)
return error;
break;
case IPC_SET:
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if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0)
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return error;
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error = copyin(SCARG(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.tv_sec;
break;
case IPC_RMID:
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if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0)
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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(SCARG(uap, shmid));
}
break;
case SHM_LOCK:
case SHM_UNLOCK:
default:
return EINVAL;
}
return 0;
}
static int
shmget_existing(p, uap, mode, segnum, retval)
struct proc *p;
struct sys_shmget_args /* {
syscallarg(key_t) key;
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syscallarg(size_t) size;
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syscallarg(int) shmflg;
} */ *uap;
int mode;
int segnum;
register_t *retval;
{
struct shmid_ds *shmseg;
struct ucred *cred = p->p_ucred;
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;
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error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0);
if (error)
return error;
return EAGAIN;
}
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if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0)
return error;
if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz)
return EINVAL;
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if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) ==
(IPC_CREAT | IPC_EXCL))
return EEXIST;
*retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
return 0;
}
static int
shmget_allocate_segment(p, uap, mode, retval)
struct proc *p;
struct sys_shmget_args /* {
syscallarg(key_t) key;
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syscallarg(size_t) size;
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syscallarg(int) shmflg;
} */ *uap;
int mode;
register_t *retval;
{
int i, segnum, shmid, size;
struct ucred *cred = p->p_ucred;
struct shmid_ds *shmseg;
struct shm_handle *shm_handle;
#ifndef UVM
vm_pager_t pager;
#endif
int error = 0;
if (SCARG(uap, size) < shminfo.shmmin ||
SCARG(uap, size) > shminfo.shmmax)
return EINVAL;
if (shm_nused >= shminfo.shmmni) /* any shmids left? */
return ENOSPC;
size = (SCARG(uap, size) + CLOFSET) & ~CLOFSET;
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 = SCARG(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);
#ifdef UVM
shm_handle->shm_object = uao_create(size, 0);
#else
shm_handle->shm_object = vm_object_allocate(size);
if (shm_handle->shm_object == NULL) {
/* XXX cannot happen */
error = ENOMEM;
goto out;
}
/*
* We make sure that we have allocated a pager before we need
* to.
*/
pager = vm_pager_allocate(PG_DFLT, 0, size, VM_PROT_DEFAULT, 0);
if (pager == NULL) {
error = ENOMEM;
goto out;
}
vm_object_setpager(shm_handle->shm_object, pager, 0, 0);
#endif
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 = SCARG(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.tv_sec;
shm_committed += btoc(size);
shm_nused++;
#ifndef UVM
out:
if (error) {
if (shm_handle->shm_object != NULL)
vm_object_deallocate(shm_handle->shm_object);
free(shm_handle, M_SHM);
shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED)
| SHMSEG_FREE;
} else
#endif
*retval = shmid;
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);
}
return error;
}
int
sys_shmget(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct sys_shmget_args /* {
syscallarg(key_t) key;
syscallarg(int) size;
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syscallarg(int) shmflg;
} */ *uap = v;
int segnum, mode, error;
mode = SCARG(uap, shmflg) & ACCESSPERMS;
if (SCARG(uap, key) != IPC_PRIVATE) {
again:
segnum = shm_find_segment_by_key(SCARG(uap, key));
if (segnum >= 0) {
error = shmget_existing(p, uap, mode, segnum, retval);
if (error == EAGAIN)
goto again;
return error;
}
if ((SCARG(uap, shmflg) & IPC_CREAT) == 0)
return ENOENT;
}
return shmget_allocate_segment(p, uap, mode, retval);
}
void
shmfork(vm1, vm2)
struct vmspace *vm1, *vm2;
{
struct shmmap_state *shmmap_s;
size_t size;
int i;
if (vm1->vm_shm == NULL) {
vm2->vm_shm = NULL;
return;
}
size = shminfo.shmseg * sizeof(struct shmmap_state);
shmmap_s = malloc(size, M_SHM, M_WAITOK);
memcpy(shmmap_s, vm1->vm_shm, size);
vm2->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(vm)
struct vmspace *vm;
{
struct shmmap_state *shmmap_s;
int i;
shmmap_s = (struct shmmap_state *)vm->vm_shm;
if (shmmap_s == NULL)
return;
for (i = 0; i < shminfo.shmseg; i++, shmmap_s++)
if (shmmap_s->shmid != -1)
shm_delete_mapping(vm, shmmap_s);
free(vm->vm_shm, M_SHM);
vm->vm_shm = NULL;
}
void
shminit()
{
int i;
shminfo.shmmax *= NBPG;
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;
}