/* $FreeBSD: src/sys/kern/sysv_shm.c,v 1.45.2.6 2002/10/22 20:45:03 fjoe Exp $ */ /* $DragonFly: src/sys/kern/sysv_shm.c,v 1.15 2004/07/23 14:07:46 joerg 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_sysvipc.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_SHM, "shm", "SVID compatible shared memory segments"); struct oshmctl_args; static int oshmctl (struct proc *p, struct oshmctl_args *uap); static int shmget_allocate_segment (struct proc *p, struct shmget_args *uap, int mode); static int shmget_existing (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, shmalloced; static 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 (struct shmid_ds *); static int shm_find_segment_by_key (key_t); static struct shmid_ds *shm_find_segment_by_shmid (int); static int shm_delete_mapping (struct vmspace *vm, struct shmmap_state *); static void shmrealloc (void); static void shminit (void *); /* * Tuneable values */ #ifndef SHMMAXPGS #define SHMMAXPGS 8192 /* note: sysv shared memory is swap backed */ #endif #ifndef SHMMAX #define SHMMAX (SHMMAXPGS*PAGE_SIZE) #endif #ifndef SHMMIN #define SHMMIN 1 #endif #ifndef SHMMNI #define SHMMNI 192 #endif #ifndef SHMSEG #define SHMSEG 128 #endif #ifndef SHMALL #define SHMALL (SHMMAXPGS) #endif struct shminfo shminfo = { SHMMAX, SHMMIN, SHMMNI, SHMSEG, SHMALL }; static int shm_use_phys; TUNABLE_INT("kern.ipc.shmmin", &shminfo.shmmin); TUNABLE_INT("kern.ipc.shmmni", &shminfo.shmmni); TUNABLE_INT("kern.ipc.shmseg", &shminfo.shmseg); TUNABLE_INT("kern.ipc.shmmaxpgs", &shminfo.shmall); TUNABLE_INT("kern.ipc.shm_use_phys", &shm_use_phys); SYSCTL_INT(_kern_ipc, OID_AUTO, shmmax, CTLFLAG_RW, &shminfo.shmmax, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmmin, CTLFLAG_RW, &shminfo.shmmin, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmmni, CTLFLAG_RD, &shminfo.shmmni, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmseg, CTLFLAG_RW, &shminfo.shmseg, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shmall, CTLFLAG_RW, &shminfo.shmall, 0, ""); SYSCTL_INT(_kern_ipc, OID_AUTO, shm_use_phys, CTLFLAG_RW, &shm_use_phys, 0, ""); static int shm_find_segment_by_key(key) key_t key; { int i; for (i = 0; i < shmalloced; 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 >= shmalloced) 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(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 = round_page(shmseg->shm_segsz); result = vm_map_remove(&vm->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; } int shmdt(struct shmdt_args *uap) { struct proc *p = curproc; struct shmmap_state *shmmap_s; int i; if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL) return (ENOSYS); 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->p_vmspace, shmmap_s); } int shmat(struct shmat_args *uap) { struct proc *p = curproc; 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; if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL) return (ENOSYS); 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); #ifdef VM_PROT_READ_IS_EXEC prot = VM_PROT_READ | VM_PROT_EXECUTE; #else prot = VM_PROT_READ; #endif 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) { vm_object_deallocate(shm_handle->shm_object); 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++; uap->sysmsg_result = 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 { struct sysmsg sysmsg; 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; if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL) return (ENOSYS); 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 (shmctl((struct shmctl_args *)uap)); } return 0; #else return EINVAL; #endif } int shmctl(struct shmctl_args *uap) { struct proc *p = curproc; int error; struct shmid_ds inbuf; struct shmid_ds *shmseg; if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL) return (ENOSYS); 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; } 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, PCATCH, "shmget", 0); if (error) return error; return EAGAIN; } if ((uap->shmflg & (IPC_CREAT | IPC_EXCL)) == (IPC_CREAT | IPC_EXCL)) return EEXIST; error = ipcperm(p, &shmseg->shm_perm, mode); if (error) return error; if (uap->size && uap->size > shmseg->shm_segsz) return EINVAL; uap->sysmsg_result = 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) { shmrealloc(); /* maybe expand the shmsegs[] array */ for (i = 0; i < shmalloced; i++) if (shmsegs[i].shm_perm.mode & SHMSEG_FREE) break; if (i == shmalloced) return ENOSPC; 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. */ if (shm_use_phys) { shm_handle->shm_object = vm_pager_allocate(OBJT_PHYS, 0, size, VM_PROT_DEFAULT, 0); } else { 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); } uap->sysmsg_result = shmid; return 0; } int shmget(struct shmget_args *uap) { struct proc *p = curproc; int segnum, mode, error; if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL) return (ENOSYS); 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); } /* * shmsys_args(int which, int a2, ...) (VARARGS) */ int shmsys(struct shmsys_args *uap) { struct proc *p = curproc; unsigned int which = (unsigned int)uap->which; int error; if (!jail_sysvipc_allowed && p->p_ucred->cr_prison != NULL) return (ENOSYS); if (which >= sizeof(shmcalls)/sizeof(shmcalls[0])) return EINVAL; bcopy(&uap->a2, &uap->which, sizeof(struct shmsys_args) - offsetof(struct shmsys_args, a2)); error = ((*shmcalls[which])(uap)); return(error); } 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(struct vmspace *vm) { struct shmmap_state *base, *shm; int i; if ((base = (struct shmmap_state *)vm->vm_shm) != NULL) { vm->vm_shm = NULL; for (i = 0, shm = base; i < shminfo.shmseg; i++, shm++) { if (shm->shmid != -1) shm_delete_mapping(vm, shm); } free(base, M_SHM); } } static void shmrealloc(void) { int i; struct shmid_ds *newsegs; if (shmalloced >= shminfo.shmmni) return; newsegs = malloc(shminfo.shmmni * sizeof(*newsegs), M_SHM, M_WAITOK); if (newsegs == NULL) return; for (i = 0; i < shmalloced; i++) bcopy(&shmsegs[i], &newsegs[i], sizeof(newsegs[0])); for (; i < shminfo.shmmni; i++) { shmsegs[i].shm_perm.mode = SHMSEG_FREE; shmsegs[i].shm_perm.seq = 0; } free(shmsegs, M_SHM); shmsegs = newsegs; shmalloced = shminfo.shmmni; } static void shminit(dummy) void *dummy; { int i; shminfo.shmmax = shminfo.shmall * PAGE_SIZE; shmalloced = shminfo.shmmni; shmsegs = malloc(shmalloced * sizeof(shmsegs[0]), M_SHM, M_WAITOK); if (shmsegs == NULL) panic("cannot allocate initial memory for sysvshm"); for (i = 0; i < shmalloced; i++) { shmsegs[i].shm_perm.mode = SHMSEG_FREE; shmsegs[i].shm_perm.seq = 0; } shm_last_free = 0; shm_nused = 0; shm_committed = 0; } SYSINIT(sysv_shm, SI_SUB_SYSV_SHM, SI_ORDER_FIRST, shminit, NULL);