/* $OpenBSD: sysv_shm.c,v 1.29 2002/11/06 00:17:28 art Exp $ */ /* $NetBSD: sysv_shm.c,v 1.50 1998/10/21 22:24:29 tron 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. * 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. * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include struct shminfo shminfo; struct shmid_ds *shmsegs; struct shmid_ds *shm_find_segment_by_shmid(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 { struct uvm_object *shm_object; }; struct shmmap_state { vaddr_t va; int shmid; }; int shm_find_segment_by_key(key_t); void shm_deallocate_segment(struct shmid_ds *); int shm_delete_mapping(struct vmspace *, struct shmmap_state *); int shmget_existing(struct proc *, struct sys_shmget_args *, int, int, register_t *); int shmget_allocate_segment(struct proc *, struct sys_shmget_args *, int, register_t *); 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 * 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; } void shm_deallocate_segment(shmseg) struct shmid_ds *shmseg; { struct shm_handle *shm_handle; size_t size; shm_handle = shmseg->shm_internal; size = round_page(shmseg->shm_segsz); uao_detach(shm_handle->shm_object); free((caddr_t)shm_handle, M_SHM); shmseg->shm_internal = NULL; shm_committed -= btoc(size); shmseg->shm_perm.mode = SHMSEG_FREE; shm_nused--; } int shm_delete_mapping(vm, shmmap_s) struct vmspace *vm; struct shmmap_state *shmmap_s; { struct shmid_ds *shmseg; int segnum; size_t size; segnum = IPCID_TO_IX(shmmap_s->shmid); shmseg = &shmsegs[segnum]; size = round_page(shmseg->shm_segsz); uvm_deallocate(&vm->vm_map, shmmap_s->va, size); 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 /* { 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; syscallarg(const void *) shmaddr; 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; 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(SCARG(uap, shmid)); if (shmseg == NULL) return EINVAL; 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 = round_page(shmseg->shm_segsz); 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 uvm_map() about where to put it. */ attach_va = round_page((vaddr_t)p->p_vmspace->vm_taddr + MAXTSIZ + MAXDSIZ); } shm_handle = shmseg->shm_internal; uao_reference(shm_handle->shm_object); error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, shm_handle->shm_object, 0, 0, UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); if (error) return (error); 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; 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: if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) return error; error = copyout((caddr_t)shmseg, SCARG(uap, buf), sizeof(inbuf)); if (error) return error; break; case IPC_SET: if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) return error; 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: if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) 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; } int shmget_existing(p, uap, mode, segnum, retval) struct proc *p; struct sys_shmget_args /* { syscallarg(key_t) key; syscallarg(size_t) size; 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; error = tsleep((caddr_t)shmseg, PLOCK | PCATCH, "shmget", 0); if (error) return error; return EAGAIN; } if ((error = ipcperm(cred, &shmseg->shm_perm, mode)) != 0) return error; if (SCARG(uap, size) && SCARG(uap, size) > shmseg->shm_segsz) return EINVAL; if ((SCARG(uap, shmflg) & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) return EEXIST; *retval = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); return 0; } int shmget_allocate_segment(p, uap, mode, retval) struct proc *p; struct sys_shmget_args /* { syscallarg(key_t) key; syscallarg(size_t) size; 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; 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 = round_page(SCARG(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 = 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); shm_handle->shm_object = uao_create(size, 0); 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++; *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; 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); bcopy(vm1->vm_shm, shmmap_s, 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 *= PAGE_SIZE; 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; } void shmid_n2o(n, o) struct shmid_ds *n; struct oshmid_ds *o; { o->shm_segsz = n->shm_segsz; o->shm_lpid = n->shm_lpid; o->shm_cpid = n->shm_cpid; o->shm_nattch = n->shm_nattch; o->shm_atime = n->shm_atime; o->shm_dtime = n->shm_dtime; o->shm_ctime = n->shm_ctime; o->shm_internal = n->shm_internal; ipc_n2o(&n->shm_perm, &o->shm_perm); }