NetBSD/sys/kern/sysv_shm.c

508 lines
13 KiB
C

/*
* Copyright (c) 1994 Adam Glass
* 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. The name of the Author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY Adam Glass ``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 Adam Glass 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/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 <vm/vm.h>
#include <vm/vm_map.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
/*
* Provides the following externally accessible functions:
*
* shminit(void); initialization
* shmexit(struct proc *) cleanup
* shmfork(struct proc *, struct proc *, int) 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'
*/
int shmat(), shmctl(), shmdt(), shmget();
int (*shmcalls[])() = { shmat, shmctl, shmdt, shmget };
#define SHMSEG_FREE 0x200
#define SHMSEG_REMOVED 0x400
#define SHMSEG_ALLOCATED 0x800
vm_map_t sysvshm_map;
int shm_last_free, shm_nused, shm_committed;
struct shm_handle {
vm_offset_t kva;
};
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, 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, where)
int shmid;
int *where;
{
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;
if (where)
*where = segnum;
return shmseg;
}
static vm_offset_t
shm_find_space(p, size)
struct proc *p;
size_t size;
{
vm_offset_t low_end, range, current;
int result;
low_end = (vm_offset_t)p->p_vmspace->vm_daddr +
(p->p_vmspace->vm_dsize << PGSHIFT);
range = (USRSTACK - low_end);
/* XXXX totally bogus */
/* current = range *3/4 + low_end */
current = ((range&1)<<1 + range)>>2 + range>>1 + low_end;
#if 0
result = vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &current, size,
TRUE);
if (result)
return NULL;
#endif
return current;
}
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;
vm_deallocate(sysvshm_map, shm_handle->kva, size);
free((caddr_t)shm_handle, M_SHM);
shmseg->shm_internal = NULL;
shm_committed -= btoc(size);
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 = (shmseg->shm_segsz + CLOFSET) & ~CLOFSET;
result = vm_deallocate(&p->p_vmspace->vm_map, shmmap_s->va, size);
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;
}
struct shmdt_args {
void *shmaddr;
};
int
shmdt(p, uap, retval)
struct proc *p;
struct shmdt_args *uap;
int *retval;
{
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 &&
shmmap_s->va == (vm_offset_t)uap->shmaddr)
break;
if (i == shminfo.shmseg)
return EINVAL;
return shm_delete_mapping(p, shmmap_s);
}
struct shmat_args {
int shmid;
void *shmaddr;
int shmflg;
};
int
shmat(p, uap, retval)
struct proc *p;
struct shmat_args *uap;
int *retval;
{
int error, i, flags;
struct ucred *cred = p->p_ucred;
struct shmid_ds *shmseg;
struct shmmap_state *shmmap_s = NULL;
vm_offset_t attach_va;
vm_prot_t prot;
vm_size_t size;
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);
bzero((caddr_t)shmmap_s, size);
p->p_vmspace->vm_shm = (caddr_t)shmmap_s;
}
shmseg = shm_find_segment_by_shmid(uap->shmid, NULL);
if (shmseg == NULL)
return EINVAL;
if (error = ipcperm(cred, &shmseg->shm_perm,
(uap->shmflg & SHM_RDONLY) ? IPC_R : IPC_R|IPC_W))
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 ((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 {
attach_va = shm_find_space(p, shmseg->shm_segsz);
if (attach_va == NULL)
return ENOMEM;
}
error = vm_mmap(&p->p_vmspace->vm_map, &attach_va, size, prot,
VM_PROT_DEFAULT, flags, uap->shmid, 0);
if (error)
return error;
shmmap_s->va = attach_va;
shmmap_s->shmid = uap->shmid;
shmseg->shm_lpid = p->p_pid;
shmseg->shm_atime = time.tv_sec;
shmseg->shm_nattch++;
*retval = attach_va;
return 0;
}
struct shmctl_args {
int shmid;
int cmd;
struct shmat_ds *ubuf;
};
int
shmctl(p, uap, retval)
struct proc *p;
struct shmctl_args *uap;
int *retval;
{
int error, segnum;
struct ucred *cred = p->p_ucred;
struct shmid_ds inbuf;
struct shmid_ds *shmseg;
shmseg = shm_find_segment_by_shmid(uap->shmid, &segnum);
if (shmseg == NULL)
return EINVAL;
switch (uap->cmd) {
case IPC_STAT:
if (error = ipcperm(cred, &shmseg->shm_perm, IPC_R))
return error;
if (error = copyout((caddr_t)shmseg, uap->ubuf, sizeof(inbuf)))
return error;
break;
case IPC_SET:
if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M))
return error;
if (error = copyin(uap->ubuf, (caddr_t)&inbuf, sizeof(inbuf)))
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:
if (error = ipcperm(cred, &shmseg->shm_perm, IPC_M))
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 = segnum;
}
break;
#if 0
case SHM_LOCK:
case SHM_UNLOCK:
#endif
default:
return EINVAL;
}
return 0;
}
struct shmget_args {
key_t key;
size_t size;
int shmflg;
};
static int
shmget_existing(p, uap, mode, segnum, retval)
struct proc *p;
struct shmget_args *uap;
int mode;
int segnum;
int *retval;
{
struct shmid_ds *shmseg;
struct ucred *cred = p->p_ucred;
int error;
shmseg = &shmsegs[segnum];
if (shmseg->shm_perm.mode & SHMSEG_REMOVED)
return EBUSY;
if (error = ipcperm(cred, &shmseg->shm_perm, mode))
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;
*retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm);
return 0;
}
static int
shmget_allocate_segment(p, uap, mode, retval)
struct proc *p;
struct shmget_args *uap;
int mode;
int *retval;
{
int i, segnum, result, 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 = (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 = 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);
result = vm_mmap(sysvshm_map, &shm_handle->kva, size, VM_PROT_ALL,
VM_PROT_DEFAULT, MAP_ANON, shmid, 0);
if (result != KERN_SUCCESS) {
shmseg->shm_perm.mode = SHMSEG_FREE;
free((caddr_t)shm_handle, M_SHM);
return ENOMEM;
}
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 = (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.tv_sec;
shm_committed += btoc(size);
shm_nused++;
*retval = shmid;
return 0;
}
int
shmget(p, uap, retval)
struct proc *p;
struct shmget_args *uap;
int *retval;
{
int segnum, mode, error;
struct shmid_ds *shmseg;
mode = uap->shmflg & ACCESSPERMS;
if (uap->key != IPC_PRIVATE) {
segnum = shm_find_segment_by_key(uap->key);
if (segnum >= 0)
return shmget_existing(p, uap, mode, segnum, retval);
if ((uap->shmflg & IPC_CREAT) == 0)
return ENOENT;
}
return shmget_allocate_segment(p, uap, mode, retval);
}
struct shmsys_args {
u_int which;
};
int
shmsys(p, uap, retval)
struct proc *p;
struct shmsys_args *uap;
int *retval;
{
if (uap->which >= sizeof(shmcalls)/sizeof(shmcalls[0]))
return EINVAL;
return ((*shmcalls[uap->which])(p, &uap[1], retval));
}
void
shmfork(p1, p2, isvfork)
struct proc *p1, *p2;
int isvfork;
{
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;
struct shmid_ds *shmseg;
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()
{
int i;
vm_offset_t garbage1, garbage2;
/* actually this *should* be pageable. SHM_{LOCK,UNLOCK} */
sysvshm_map = kmem_suballoc(kernel_map, &garbage1, &garbage2,
shminfo.shmall * NBPG, FALSE);
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;
}