/* $NetBSD: sysv_shm.c,v 1.89 2006/07/23 22:06:11 ad Exp $ */ /*- * Copyright (c) 1999 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, * NASA Ames Research Center. * * 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 the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * 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 __KERNEL_RCSID(0, "$NetBSD: sysv_shm.c,v 1.89 2006/07/23 22:06:11 ad Exp $"); #define SYSVSHM #include #include #include #include #include #include #include #include /* XXX for */ #include #include #include #include #include #include #include static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); /* * Provides the following externally accessible functions: * * shminit(void); initialization * shmexit(struct vmspace *) cleanup * shmfork(struct vmspace *, struct vmspace *) fork handling * * Structures: * shmsegs (an array of 'struct shmid_ds') * per proc array of 'struct shmmap_state' */ int shm_nused; struct shmid_ds *shmsegs; struct shmmap_entry { SLIST_ENTRY(shmmap_entry) next; vaddr_t va; int shmid; }; static int shm_last_free, shm_committed; static POOL_INIT(shmmap_entry_pool, sizeof(struct shmmap_entry), 0, 0, 0, "shmmp", &pool_allocator_nointr); struct shmmap_state { unsigned int nitems; unsigned int nrefs; SLIST_HEAD(, shmmap_entry) entries; }; static int shm_find_segment_by_key(key_t); static void shm_deallocate_segment(struct shmid_ds *); static void shm_delete_mapping(struct vmspace *, struct shmmap_state *, struct shmmap_entry *); static int shmget_existing(struct lwp *, struct sys_shmget_args *, int, int, register_t *); static int shmget_allocate_segment(struct lwp *, struct sys_shmget_args *, int, register_t *); static struct shmmap_state *shmmap_getprivate(struct proc *); static struct shmmap_entry *shm_find_mapping(struct shmmap_state *, vaddr_t); static int shm_find_segment_by_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(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) == 0) return NULL; if ((shmseg->shm_perm.mode & (SHMSEG_REMOVED|SHMSEG_RMLINGER)) == SHMSEG_REMOVED) return NULL; if (shmseg->shm_perm._seq != IPCID_TO_SEQ(shmid)) return NULL; return shmseg; } static void shm_deallocate_segment(struct shmid_ds *shmseg) { struct uvm_object *uobj = shmseg->_shm_internal; size_t size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; #ifdef SHMDEBUG printf("shm freeing key 0x%lx seq 0x%x\n", shmseg->shm_perm._key, shmseg->shm_perm._seq); #endif (*uobj->pgops->pgo_detach)(uobj); shmseg->_shm_internal = NULL; shm_committed -= btoc(size); shmseg->shm_perm.mode = SHMSEG_FREE; shm_nused--; } static void shm_delete_mapping(struct vmspace *vm, struct shmmap_state *shmmap_s, struct shmmap_entry *shmmap_se) { struct shmid_ds *shmseg; int segnum; size_t size; segnum = IPCID_TO_IX(shmmap_se->shmid); #ifdef DEBUG if (segnum < 0 || segnum >= shminfo.shmmni) panic("shm_delete_mapping: vmspace %p state %p entry %p - " "entry segment ID bad (%d)", vm, shmmap_s, shmmap_se, segnum); #endif shmseg = &shmsegs[segnum]; size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; uvm_deallocate(&vm->vm_map, shmmap_se->va, size); SLIST_REMOVE(&shmmap_s->entries, shmmap_se, shmmap_entry, next); shmmap_s->nitems--; pool_put(&shmmap_entry_pool, shmmap_se); shmseg->shm_dtime = time_second; if ((--shmseg->shm_nattch <= 0) && (shmseg->shm_perm.mode & SHMSEG_REMOVED)) { shm_deallocate_segment(shmseg); shm_last_free = segnum; } } /* * Get a non-shared shm map for that vmspace. * 3 cases: * - no shm map present: create a fresh one * - a shm map with refcount=1, just used by ourselves: fine * - a shared shm map: copy to a fresh one and adjust refcounts */ static struct shmmap_state * shmmap_getprivate(struct proc *p) { struct shmmap_state *oshmmap_s, *shmmap_s; struct shmmap_entry *oshmmap_se, *shmmap_se; oshmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; if (oshmmap_s && oshmmap_s->nrefs == 1) return (oshmmap_s); shmmap_s = malloc(sizeof(struct shmmap_state), M_SHM, M_WAITOK); memset(shmmap_s, 0, sizeof(struct shmmap_state)); shmmap_s->nrefs = 1; SLIST_INIT(&shmmap_s->entries); p->p_vmspace->vm_shm = (caddr_t)shmmap_s; if (!oshmmap_s) return (shmmap_s); #ifdef SHMDEBUG printf("shmmap_getprivate: vm %p split (%d entries), was used by %d\n", p->p_vmspace, oshmmap_s->nitems, oshmmap_s->nrefs); #endif SLIST_FOREACH(oshmmap_se, &oshmmap_s->entries, next) { shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); shmmap_se->va = oshmmap_se->va; shmmap_se->shmid = oshmmap_se->shmid; SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); } shmmap_s->nitems = oshmmap_s->nitems; oshmmap_s->nrefs--; return (shmmap_s); } static struct shmmap_entry * shm_find_mapping(struct shmmap_state *map, vaddr_t va) { struct shmmap_entry *shmmap_se; SLIST_FOREACH(shmmap_se, &map->entries, next) { if (shmmap_se->va == va) return shmmap_se; } return 0; } int sys_shmdt(struct lwp *l, void *v, register_t *retval) { struct sys_shmdt_args /* { syscallarg(const void *) shmaddr; } */ *uap = v; struct proc *p = l->l_proc; struct shmmap_state *shmmap_s, *shmmap_s1; struct shmmap_entry *shmmap_se; shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; if (shmmap_s == NULL) return EINVAL; shmmap_se = shm_find_mapping(shmmap_s, (vaddr_t)SCARG(uap, shmaddr)); if (!shmmap_se) return EINVAL; shmmap_s1 = shmmap_getprivate(p); if (shmmap_s1 != shmmap_s) { /* map has been copied, lookup entry in new map */ shmmap_se = shm_find_mapping(shmmap_s1, (vaddr_t)SCARG(uap, shmaddr)); KASSERT(shmmap_se != NULL); } #ifdef SHMDEBUG printf("shmdt: vm %p: remove %d @%lx\n", p->p_vmspace, shmmap_se->shmid, shmmap_se->va); #endif shm_delete_mapping(p->p_vmspace, shmmap_s1, shmmap_se); return 0; } int sys_shmat(struct lwp *l, void *v, register_t *retval) { struct sys_shmat_args /* { syscallarg(int) shmid; syscallarg(const void *) shmaddr; syscallarg(int) shmflg; } */ *uap = v; int error, flags; struct proc *p = l->l_proc; kauth_cred_t cred = l->l_cred; struct shmid_ds *shmseg; struct shmmap_state *shmmap_s; struct uvm_object *uobj; vaddr_t attach_va; vm_prot_t prot; vsize_t size; struct shmmap_entry *shmmap_se; 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; shmmap_s = (struct shmmap_state *)p->p_vmspace->vm_shm; if (shmmap_s && shmmap_s->nitems >= shminfo.shmseg) return EMFILE; size = (shmseg->shm_segsz + PGOFSET) & ~PGOFSET; 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_mmap() about where to put it. */ attach_va = p->p_emul->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr, size); } uobj = shmseg->_shm_internal; (*uobj->pgops->pgo_reference)(uobj); error = uvm_map(&p->p_vmspace->vm_map, &attach_va, size, uobj, 0, 0, UVM_MAPFLAG(prot, prot, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); if (error) { (*uobj->pgops->pgo_detach)(uobj); return error; } shmmap_se = pool_get(&shmmap_entry_pool, PR_WAITOK); shmmap_se->va = attach_va; shmmap_se->shmid = SCARG(uap, shmid); shmmap_s = shmmap_getprivate(p); #ifdef SHMDEBUG printf("shmat: vm %p: add %d @%lx\n", p->p_vmspace, shmmap_se->shmid, attach_va); #endif SLIST_INSERT_HEAD(&shmmap_s->entries, shmmap_se, next); shmmap_s->nitems++; shmseg->shm_lpid = p->p_pid; shmseg->shm_atime = time_second; shmseg->shm_nattch++; retval[0] = attach_va; return 0; } int sys___shmctl13(struct lwp *l, void *v, register_t *retval) { struct sys___shmctl13_args /* { syscallarg(int) shmid; syscallarg(int) cmd; syscallarg(struct shmid_ds *) buf; } */ *uap = v; struct shmid_ds shmbuf; int cmd, error; cmd = SCARG(uap, cmd); if (cmd == IPC_SET) { error = copyin(SCARG(uap, buf), &shmbuf, sizeof(shmbuf)); if (error) return (error); } error = shmctl1(l, SCARG(uap, shmid), cmd, (cmd == IPC_SET || cmd == IPC_STAT) ? &shmbuf : NULL); if (error == 0 && cmd == IPC_STAT) error = copyout(&shmbuf, SCARG(uap, buf), sizeof(shmbuf)); return (error); } int shmctl1(struct lwp *l, int shmid, int cmd, struct shmid_ds *shmbuf) { kauth_cred_t cred = l->l_cred; struct shmid_ds *shmseg; int error = 0; shmseg = shm_find_segment_by_shmid(shmid); if (shmseg == NULL) return EINVAL; switch (cmd) { case IPC_STAT: if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_R)) != 0) return error; memcpy(shmbuf, shmseg, sizeof(struct shmid_ds)); break; case IPC_SET: if ((error = ipcperm(cred, &shmseg->shm_perm, IPC_M)) != 0) return error; shmseg->shm_perm.uid = shmbuf->shm_perm.uid; shmseg->shm_perm.gid = shmbuf->shm_perm.gid; shmseg->shm_perm.mode = (shmseg->shm_perm.mode & ~ACCESSPERMS) | (shmbuf->shm_perm.mode & ACCESSPERMS); shmseg->shm_ctime = time_second; 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(shmid); } break; case SHM_LOCK: case SHM_UNLOCK: default: return EINVAL; } return 0; } static int shmget_existing(struct lwp *l, struct sys_shmget_args *uap, int mode, int segnum, register_t *retval) { struct shmid_ds *shmseg; kauth_cred_t cred = l->l_cred; 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; } static int shmget_allocate_segment(struct lwp *l, struct sys_shmget_args *uap, int mode, register_t *retval) { int i, segnum, shmid, size; kauth_cred_t cred = l->l_cred; struct shmid_ds *shmseg; 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) + PGOFSET) & ~PGOFSET; 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; shmid = IXSEQ_TO_IPCID(segnum, shmseg->shm_perm); shmseg->_shm_internal = uao_create(size, 0); shmseg->shm_perm.cuid = shmseg->shm_perm.uid = kauth_cred_geteuid(cred); shmseg->shm_perm.cgid = shmseg->shm_perm.gid = kauth_cred_getegid(cred); shmseg->shm_perm.mode = (shmseg->shm_perm.mode & SHMSEG_WANTED) | (mode & (ACCESSPERMS|SHMSEG_RMLINGER)) | SHMSEG_ALLOCATED; shmseg->shm_segsz = SCARG(uap, size); shmseg->shm_cpid = l->l_proc->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++; *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(struct lwp *l, 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, shmflg) & _SHM_RMLINGER) mode |= SHMSEG_RMLINGER; #ifdef SHMDEBUG printf("shmget: key 0x%lx size 0x%x shmflg 0x%x mode 0x%x\n", SCARG(uap, key), SCARG(uap, size), SCARG(uap, shmflg), mode); #endif if (SCARG(uap, key) != IPC_PRIVATE) { again: segnum = shm_find_segment_by_key(SCARG(uap, key)); if (segnum >= 0) { error = shmget_existing(l, uap, mode, segnum, retval); if (error == EAGAIN) goto again; return error; } if ((SCARG(uap, shmflg) & IPC_CREAT) == 0) return ENOENT; } return shmget_allocate_segment(l, uap, mode, retval); } void shmfork(struct vmspace *vm1, struct vmspace *vm2) { struct shmmap_state *shmmap_s; struct shmmap_entry *shmmap_se; vm2->vm_shm = vm1->vm_shm; if (vm1->vm_shm == NULL) return; #ifdef SHMDEBUG printf("shmfork %p->%p\n", vm1, vm2); #endif shmmap_s = (struct shmmap_state *)vm1->vm_shm; SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch++; shmmap_s->nrefs++; } void shmexit(struct vmspace *vm) { struct shmmap_state *shmmap_s; struct shmmap_entry *shmmap_se; shmmap_s = (struct shmmap_state *)vm->vm_shm; if (shmmap_s == NULL) return; vm->vm_shm = NULL; if (--shmmap_s->nrefs > 0) { #ifdef SHMDEBUG printf("shmexit: vm %p drop ref (%d entries), now used by %d\n", vm, shmmap_s->nitems, shmmap_s->nrefs); #endif SLIST_FOREACH(shmmap_se, &shmmap_s->entries, next) shmsegs[IPCID_TO_IX(shmmap_se->shmid)].shm_nattch--; return; } #ifdef SHMDEBUG printf("shmexit: vm %p cleanup (%d entries)\n", vm, shmmap_s->nitems); #endif while (!SLIST_EMPTY(&shmmap_s->entries)) { shmmap_se = SLIST_FIRST(&shmmap_s->entries); shm_delete_mapping(vm, shmmap_s, shmmap_se); } KASSERT(shmmap_s->nitems == 0); free(shmmap_s, M_SHM); } void shminit(void) { int i, sz; vaddr_t v; /* Allocate pageable memory for our structures */ sz = shminfo.shmmni * sizeof(struct shmid_ds); v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED); if (v == 0) panic("sysv_shm: cannot allocate memory"); shmsegs = (void *)v; 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; }