/* $NetBSD: sysv_msg.c,v 1.57 2008/05/22 11:25:54 njoly Exp $ */ /*- * Copyright (c) 1999, 2006, 2007 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, and by Andrew Doran. * * 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. * * 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. */ /* * Implementation of SVID messages * * Author: Daniel Boulet * * Copyright 1993 Daniel Boulet and RTMX Inc. * * This system call was implemented by Daniel Boulet under contract from RTMX. * * Redistribution and use in source forms, with and without modification, * are permitted provided that this entire comment appears intact. * * Redistribution in binary form may occur without any restrictions. * Obviously, it would be nice if you gave credit where credit is due * but requiring it would be too onerous. * * This software is provided ``AS IS'' without any warranties of any kind. */ #include __KERNEL_RCSID(0, "$NetBSD: sysv_msg.c,v 1.57 2008/05/22 11:25:54 njoly Exp $"); #define SYSVMSG #include #include #include #include #include /* XXX for */ #include #include #define MSG_DEBUG #undef MSG_DEBUG_OK #ifdef MSG_DEBUG_OK #define MSG_PRINTF(a) printf a #else #define MSG_PRINTF(a) #endif static int nfree_msgmaps; /* # of free map entries */ static short free_msgmaps; /* head of linked list of free map entries */ static struct __msg *free_msghdrs; /* list of free msg headers */ static char *msgpool; /* MSGMAX byte long msg buffer pool */ static struct msgmap *msgmaps; /* MSGSEG msgmap structures */ static struct __msg *msghdrs; /* MSGTQL msg headers */ kmsq_t *msqs; /* MSGMNI msqid_ds struct's */ kmutex_t msgmutex; /* subsystem lock */ static u_int msg_waiters = 0; /* total number of msgrcv waiters */ static bool msg_realloc_state; static kcondvar_t msg_realloc_cv; static void msg_freehdr(struct __msg *); void msginit(void) { int i, sz; vaddr_t v; /* * msginfo.msgssz should be a power of two for efficiency reasons. * It is also pretty silly if msginfo.msgssz is less than 8 * or greater than about 256 so ... */ i = 8; while (i < 1024 && i != msginfo.msgssz) i <<= 1; if (i != msginfo.msgssz) { panic("msginfo.msgssz = %d, not a small power of 2", msginfo.msgssz); } if (msginfo.msgseg > 32767) { panic("msginfo.msgseg = %d > 32767", msginfo.msgseg); } /* Allocate the wired memory for our structures */ sz = ALIGN(msginfo.msgmax) + ALIGN(msginfo.msgseg * sizeof(struct msgmap)) + ALIGN(msginfo.msgtql * sizeof(struct __msg)) + ALIGN(msginfo.msgmni * sizeof(kmsq_t)); v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED|UVM_KMF_ZERO); if (v == 0) panic("sysv_msg: cannot allocate memory"); msgpool = (void *)v; msgmaps = (void *)(ALIGN(msgpool) + msginfo.msgmax); msghdrs = (void *)(ALIGN(msgmaps) + msginfo.msgseg * sizeof(struct msgmap)); msqs = (void *)(ALIGN(msghdrs) + msginfo.msgtql * sizeof(struct __msg)); for (i = 0; i < (msginfo.msgseg - 1); i++) msgmaps[i].next = i + 1; msgmaps[msginfo.msgseg - 1].next = -1; free_msgmaps = 0; nfree_msgmaps = msginfo.msgseg; for (i = 0; i < (msginfo.msgtql - 1); i++) { msghdrs[i].msg_type = 0; msghdrs[i].msg_next = &msghdrs[i + 1]; } i = msginfo.msgtql - 1; msghdrs[i].msg_type = 0; msghdrs[i].msg_next = NULL; free_msghdrs = &msghdrs[0]; for (i = 0; i < msginfo.msgmni; i++) { cv_init(&msqs[i].msq_cv, "msgwait"); /* Implies entry is available */ msqs[i].msq_u.msg_qbytes = 0; /* Reset to a known value */ msqs[i].msq_u.msg_perm._seq = 0; } mutex_init(&msgmutex, MUTEX_DEFAULT, IPL_NONE); cv_init(&msg_realloc_cv, "msgrealc"); msg_realloc_state = false; } static int msgrealloc(int newmsgmni, int newmsgseg) { struct msgmap *new_msgmaps; struct __msg *new_msghdrs, *new_free_msghdrs; char *old_msgpool, *new_msgpool; kmsq_t *new_msqs; vaddr_t v; int i, sz, msqid, newmsgmax, new_nfree_msgmaps; short new_free_msgmaps; if (newmsgmni < 1 || newmsgseg < 1) return EINVAL; /* Allocate the wired memory for our structures */ newmsgmax = msginfo.msgssz * newmsgseg; sz = ALIGN(newmsgmax) + ALIGN(newmsgseg * sizeof(struct msgmap)) + ALIGN(msginfo.msgtql * sizeof(struct __msg)) + ALIGN(newmsgmni * sizeof(kmsq_t)); v = uvm_km_alloc(kernel_map, round_page(sz), 0, UVM_KMF_WIRED|UVM_KMF_ZERO); if (v == 0) return ENOMEM; mutex_enter(&msgmutex); if (msg_realloc_state) { mutex_exit(&msgmutex); uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); return EBUSY; } msg_realloc_state = true; if (msg_waiters) { /* * Mark reallocation state, wake-up all waiters, * and wait while they will all exit. */ for (i = 0; i < msginfo.msgmni; i++) cv_broadcast(&msqs[i].msq_cv); while (msg_waiters) cv_wait(&msg_realloc_cv, &msgmutex); } old_msgpool = msgpool; /* We cannot reallocate less memory than we use */ i = 0; for (msqid = 0; msqid < msginfo.msgmni; msqid++) { struct msqid_ds *mptr; kmsq_t *msq; msq = &msqs[msqid]; mptr = &msq->msq_u; if (mptr->msg_qbytes || (mptr->msg_perm.mode & MSG_LOCKED)) i = msqid; } if (i >= newmsgmni || (msginfo.msgseg - nfree_msgmaps) > newmsgseg) { mutex_exit(&msgmutex); uvm_km_free(kernel_map, v, sz, UVM_KMF_WIRED); return EBUSY; } new_msgpool = (void *)v; new_msgmaps = (void *)(ALIGN(new_msgpool) + newmsgmax); new_msghdrs = (void *)(ALIGN(new_msgmaps) + newmsgseg * sizeof(struct msgmap)); new_msqs = (void *)(ALIGN(new_msghdrs) + msginfo.msgtql * sizeof(struct __msg)); /* Initialize the structures */ for (i = 0; i < (newmsgseg - 1); i++) new_msgmaps[i].next = i + 1; new_msgmaps[newmsgseg - 1].next = -1; new_free_msgmaps = 0; new_nfree_msgmaps = newmsgseg; for (i = 0; i < (msginfo.msgtql - 1); i++) { new_msghdrs[i].msg_type = 0; new_msghdrs[i].msg_next = &new_msghdrs[i + 1]; } i = msginfo.msgtql - 1; new_msghdrs[i].msg_type = 0; new_msghdrs[i].msg_next = NULL; new_free_msghdrs = &new_msghdrs[0]; for (i = 0; i < newmsgmni; i++) { new_msqs[i].msq_u.msg_qbytes = 0; new_msqs[i].msq_u.msg_perm._seq = 0; cv_init(&new_msqs[i].msq_cv, "msgwait"); } /* * Copy all message queue identifiers, mesage headers and buffer * pools to the new memory location. */ for (msqid = 0; msqid < msginfo.msgmni; msqid++) { struct __msg *nmsghdr, *msghdr, *pmsghdr; struct msqid_ds *nmptr, *mptr; kmsq_t *nmsq, *msq; msq = &msqs[msqid]; mptr = &msq->msq_u; if (mptr->msg_qbytes == 0 && (mptr->msg_perm.mode & MSG_LOCKED) == 0) continue; nmsq = &new_msqs[msqid]; nmptr = &nmsq->msq_u; memcpy(nmptr, mptr, sizeof(struct msqid_ds)); /* * Go through the message headers, and and copy each * one by taking the new ones, and thus defragmenting. */ nmsghdr = pmsghdr = NULL; msghdr = mptr->_msg_first; while (msghdr) { short nnext = 0, next; u_short msgsz, segcnt; /* Take an entry from the new list of free msghdrs */ nmsghdr = new_free_msghdrs; KASSERT(nmsghdr != NULL); new_free_msghdrs = nmsghdr->msg_next; nmsghdr->msg_next = NULL; if (pmsghdr) { pmsghdr->msg_next = nmsghdr; } else { nmptr->_msg_first = nmsghdr; pmsghdr = nmsghdr; } nmsghdr->msg_ts = msghdr->msg_ts; nmsghdr->msg_spot = -1; /* Compute the amount of segments and reserve them */ msgsz = msghdr->msg_ts; segcnt = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; if (segcnt == 0) continue; while (segcnt--) { nnext = new_free_msgmaps; new_free_msgmaps = new_msgmaps[nnext].next; new_nfree_msgmaps--; new_msgmaps[nnext].next = nmsghdr->msg_spot; nmsghdr->msg_spot = nnext; } /* Copy all segments */ KASSERT(nnext == nmsghdr->msg_spot); next = msghdr->msg_spot; while (msgsz > 0) { size_t tlen; if (msgsz >= msginfo.msgssz) { tlen = msginfo.msgssz; msgsz -= msginfo.msgssz; } else { tlen = msgsz; msgsz = 0; } /* Copy the message buffer */ memcpy(&new_msgpool[nnext * msginfo.msgssz], &msgpool[next * msginfo.msgssz], tlen); /* Next entry of the map */ nnext = msgmaps[nnext].next; next = msgmaps[next].next; } /* Next message header */ msghdr = msghdr->msg_next; } nmptr->_msg_last = nmsghdr; } KASSERT((msginfo.msgseg - nfree_msgmaps) == (newmsgseg - new_nfree_msgmaps)); sz = ALIGN(msginfo.msgmax) + ALIGN(msginfo.msgseg * sizeof(struct msgmap)) + ALIGN(msginfo.msgtql * sizeof(struct __msg)) + ALIGN(msginfo.msgmni * sizeof(kmsq_t)); for (i = 0; i < msginfo.msgmni; i++) cv_destroy(&msqs[i].msq_cv); /* Set the pointers and update the new values */ msgpool = new_msgpool; msgmaps = new_msgmaps; msghdrs = new_msghdrs; msqs = new_msqs; free_msghdrs = new_free_msghdrs; free_msgmaps = new_free_msgmaps; nfree_msgmaps = new_nfree_msgmaps; msginfo.msgmni = newmsgmni; msginfo.msgseg = newmsgseg; msginfo.msgmax = newmsgmax; /* Reallocation completed - notify all waiters, if any */ msg_realloc_state = false; cv_broadcast(&msg_realloc_cv); mutex_exit(&msgmutex); uvm_km_free(kernel_map, (vaddr_t)old_msgpool, sz, UVM_KMF_WIRED); return 0; } static void msg_freehdr(struct __msg *msghdr) { KASSERT(mutex_owned(&msgmutex)); while (msghdr->msg_ts > 0) { short next; KASSERT(msghdr->msg_spot >= 0); KASSERT(msghdr->msg_spot < msginfo.msgseg); next = msgmaps[msghdr->msg_spot].next; msgmaps[msghdr->msg_spot].next = free_msgmaps; free_msgmaps = msghdr->msg_spot; nfree_msgmaps++; msghdr->msg_spot = next; if (msghdr->msg_ts >= msginfo.msgssz) msghdr->msg_ts -= msginfo.msgssz; else msghdr->msg_ts = 0; } KASSERT(msghdr->msg_spot == -1); msghdr->msg_next = free_msghdrs; free_msghdrs = msghdr; } int sys___msgctl13(struct lwp *l, const struct sys___msgctl13_args *uap, register_t *retval) { /* { syscallarg(int) msqid; syscallarg(int) cmd; syscallarg(struct msqid_ds *) buf; } */ struct msqid_ds msqbuf; int cmd, error; cmd = SCARG(uap, cmd); if (cmd == IPC_SET) { error = copyin(SCARG(uap, buf), &msqbuf, sizeof(msqbuf)); if (error) return (error); } error = msgctl1(l, SCARG(uap, msqid), cmd, (cmd == IPC_SET || cmd == IPC_STAT) ? &msqbuf : NULL); if (error == 0 && cmd == IPC_STAT) error = copyout(&msqbuf, SCARG(uap, buf), sizeof(msqbuf)); return (error); } int msgctl1(struct lwp *l, int msqid, int cmd, struct msqid_ds *msqbuf) { kauth_cred_t cred = l->l_cred; struct msqid_ds *msqptr; kmsq_t *msq; int error = 0, ix; MSG_PRINTF(("call to msgctl1(%d, %d)\n", msqid, cmd)); ix = IPCID_TO_IX(msqid); mutex_enter(&msgmutex); if (ix < 0 || ix >= msginfo.msgmni) { MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", ix, msginfo.msgmni)); error = EINVAL; goto unlock; } msq = &msqs[ix]; msqptr = &msq->msq_u; if (msqptr->msg_qbytes == 0) { MSG_PRINTF(("no such msqid\n")); error = EINVAL; goto unlock; } if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqid)) { MSG_PRINTF(("wrong sequence number\n")); error = EINVAL; goto unlock; } switch (cmd) { case IPC_RMID: { struct __msg *msghdr; if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_M)) != 0) break; /* Free the message headers */ msghdr = msqptr->_msg_first; while (msghdr != NULL) { struct __msg *msghdr_tmp; /* Free the segments of each message */ msqptr->_msg_cbytes -= msghdr->msg_ts; msqptr->msg_qnum--; msghdr_tmp = msghdr; msghdr = msghdr->msg_next; msg_freehdr(msghdr_tmp); } KASSERT(msqptr->_msg_cbytes == 0); KASSERT(msqptr->msg_qnum == 0); /* Mark it as free */ msqptr->msg_qbytes = 0; cv_broadcast(&msq->msq_cv); } break; case IPC_SET: if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_M))) break; if (msqbuf->msg_qbytes > msqptr->msg_qbytes && kauth_authorize_generic(cred, KAUTH_GENERIC_ISSUSER, NULL) != 0) { error = EPERM; break; } if (msqbuf->msg_qbytes > msginfo.msgmnb) { MSG_PRINTF(("can't increase msg_qbytes beyond %d " "(truncating)\n", msginfo.msgmnb)); /* silently restrict qbytes to system limit */ msqbuf->msg_qbytes = msginfo.msgmnb; } if (msqbuf->msg_qbytes == 0) { MSG_PRINTF(("can't reduce msg_qbytes to 0\n")); error = EINVAL; /* XXX non-standard errno! */ break; } msqptr->msg_perm.uid = msqbuf->msg_perm.uid; msqptr->msg_perm.gid = msqbuf->msg_perm.gid; msqptr->msg_perm.mode = (msqptr->msg_perm.mode & ~0777) | (msqbuf->msg_perm.mode & 0777); msqptr->msg_qbytes = msqbuf->msg_qbytes; msqptr->msg_ctime = time_second; break; case IPC_STAT: if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) { MSG_PRINTF(("requester doesn't have read access\n")); break; } memcpy(msqbuf, msqptr, sizeof(struct msqid_ds)); break; default: MSG_PRINTF(("invalid command %d\n", cmd)); error = EINVAL; break; } unlock: mutex_exit(&msgmutex); return (error); } int sys_msgget(struct lwp *l, const struct sys_msgget_args *uap, register_t *retval) { /* { syscallarg(key_t) key; syscallarg(int) msgflg; } */ int msqid, error = 0; int key = SCARG(uap, key); int msgflg = SCARG(uap, msgflg); kauth_cred_t cred = l->l_cred; struct msqid_ds *msqptr = NULL; kmsq_t *msq; mutex_enter(&msgmutex); MSG_PRINTF(("msgget(0x%x, 0%o)\n", key, msgflg)); if (key != IPC_PRIVATE) { for (msqid = 0; msqid < msginfo.msgmni; msqid++) { msq = &msqs[msqid]; msqptr = &msq->msq_u; if (msqptr->msg_qbytes != 0 && msqptr->msg_perm._key == key) break; } if (msqid < msginfo.msgmni) { MSG_PRINTF(("found public key\n")); if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) { MSG_PRINTF(("not exclusive\n")); error = EEXIST; goto unlock; } if ((error = ipcperm(cred, &msqptr->msg_perm, msgflg & 0700 ))) { MSG_PRINTF(("requester doesn't have 0%o access\n", msgflg & 0700)); goto unlock; } goto found; } } MSG_PRINTF(("need to allocate the msqid_ds\n")); if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) { for (msqid = 0; msqid < msginfo.msgmni; msqid++) { /* * Look for an unallocated and unlocked msqid_ds. * msqid_ds's can be locked by msgsnd or msgrcv while * they are copying the message in/out. We can't * re-use the entry until they release it. */ msq = &msqs[msqid]; msqptr = &msq->msq_u; if (msqptr->msg_qbytes == 0 && (msqptr->msg_perm.mode & MSG_LOCKED) == 0) break; } if (msqid == msginfo.msgmni) { MSG_PRINTF(("no more msqid_ds's available\n")); error = ENOSPC; goto unlock; } MSG_PRINTF(("msqid %d is available\n", msqid)); msqptr->msg_perm._key = key; msqptr->msg_perm.cuid = kauth_cred_geteuid(cred); msqptr->msg_perm.uid = kauth_cred_geteuid(cred); msqptr->msg_perm.cgid = kauth_cred_getegid(cred); msqptr->msg_perm.gid = kauth_cred_getegid(cred); msqptr->msg_perm.mode = (msgflg & 0777); /* Make sure that the returned msqid is unique */ msqptr->msg_perm._seq++; msqptr->_msg_first = NULL; msqptr->_msg_last = NULL; msqptr->_msg_cbytes = 0; msqptr->msg_qnum = 0; msqptr->msg_qbytes = msginfo.msgmnb; msqptr->msg_lspid = 0; msqptr->msg_lrpid = 0; msqptr->msg_stime = 0; msqptr->msg_rtime = 0; msqptr->msg_ctime = time_second; } else { MSG_PRINTF(("didn't find it and wasn't asked to create it\n")); error = ENOENT; goto unlock; } found: /* Construct the unique msqid */ *retval = IXSEQ_TO_IPCID(msqid, msqptr->msg_perm); unlock: mutex_exit(&msgmutex); return (error); } int sys_msgsnd(struct lwp *l, const struct sys_msgsnd_args *uap, register_t *retval) { /* { syscallarg(int) msqid; syscallarg(const void *) msgp; syscallarg(size_t) msgsz; syscallarg(int) msgflg; } */ return msgsnd1(l, SCARG(uap, msqid), SCARG(uap, msgp), SCARG(uap, msgsz), SCARG(uap, msgflg), sizeof(long), copyin); } int msgsnd1(struct lwp *l, int msqidr, const char *user_msgp, size_t msgsz, int msgflg, size_t typesz, copyin_t fetch_type) { int segs_needed, error = 0, msqid; kauth_cred_t cred = l->l_cred; struct msqid_ds *msqptr; struct __msg *msghdr; kmsq_t *msq; short next; MSG_PRINTF(("call to msgsnd(%d, %p, %lld, %d)\n", msqid, user_msgp, (long long)msgsz, msgflg)); restart: msqid = IPCID_TO_IX(msqidr); mutex_enter(&msgmutex); /* In case of reallocation, we will wait for completion */ while (__predict_false(msg_realloc_state)) cv_wait(&msg_realloc_cv, &msgmutex); if (msqid < 0 || msqid >= msginfo.msgmni) { MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, msginfo.msgmni)); error = EINVAL; goto unlock; } msq = &msqs[msqid]; msqptr = &msq->msq_u; if (msqptr->msg_qbytes == 0) { MSG_PRINTF(("no such message queue id\n")); error = EINVAL; goto unlock; } if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { MSG_PRINTF(("wrong sequence number\n")); error = EINVAL; goto unlock; } if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_W))) { MSG_PRINTF(("requester doesn't have write access\n")); goto unlock; } segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; MSG_PRINTF(("msgsz=%lld, msgssz=%d, segs_needed=%d\n", (long long)msgsz, msginfo.msgssz, segs_needed)); for (;;) { int need_more_resources = 0; /* * check msgsz [cannot be negative since it is unsigned] * (inside this loop in case msg_qbytes changes while we sleep) */ if (msgsz > msqptr->msg_qbytes) { MSG_PRINTF(("msgsz > msqptr->msg_qbytes\n")); error = EINVAL; goto unlock; } if (msqptr->msg_perm.mode & MSG_LOCKED) { MSG_PRINTF(("msqid is locked\n")); need_more_resources = 1; } if (msgsz + msqptr->_msg_cbytes > msqptr->msg_qbytes) { MSG_PRINTF(("msgsz + msg_cbytes > msg_qbytes\n")); need_more_resources = 1; } if (segs_needed > nfree_msgmaps) { MSG_PRINTF(("segs_needed > nfree_msgmaps\n")); need_more_resources = 1; } if (free_msghdrs == NULL) { MSG_PRINTF(("no more msghdrs\n")); need_more_resources = 1; } if (need_more_resources) { int we_own_it; if ((msgflg & IPC_NOWAIT) != 0) { MSG_PRINTF(("need more resources but caller " "doesn't want to wait\n")); error = EAGAIN; goto unlock; } if ((msqptr->msg_perm.mode & MSG_LOCKED) != 0) { MSG_PRINTF(("we don't own the msqid_ds\n")); we_own_it = 0; } else { /* Force later arrivals to wait for our request */ MSG_PRINTF(("we own the msqid_ds\n")); msqptr->msg_perm.mode |= MSG_LOCKED; we_own_it = 1; } msg_waiters++; MSG_PRINTF(("goodnight\n")); error = cv_wait_sig(&msq->msq_cv, &msgmutex); MSG_PRINTF(("good morning, error=%d\n", error)); msg_waiters--; if (we_own_it) msqptr->msg_perm.mode &= ~MSG_LOCKED; /* * In case of such state, notify reallocator and * restart the call. */ if (msg_realloc_state) { cv_broadcast(&msg_realloc_cv); mutex_exit(&msgmutex); goto restart; } if (error != 0) { MSG_PRINTF(("msgsnd: interrupted system " "call\n")); error = EINTR; goto unlock; } /* * Make sure that the msq queue still exists */ if (msqptr->msg_qbytes == 0) { MSG_PRINTF(("msqid deleted\n")); error = EIDRM; goto unlock; } } else { MSG_PRINTF(("got all the resources that we need\n")); break; } } /* * We have the resources that we need. * Make sure! */ KASSERT((msqptr->msg_perm.mode & MSG_LOCKED) == 0); KASSERT(segs_needed <= nfree_msgmaps); KASSERT(msgsz + msqptr->_msg_cbytes <= msqptr->msg_qbytes); KASSERT(free_msghdrs != NULL); /* * Re-lock the msqid_ds in case we page-fault when copying in the * message */ KASSERT((msqptr->msg_perm.mode & MSG_LOCKED) == 0); msqptr->msg_perm.mode |= MSG_LOCKED; /* * Allocate a message header */ msghdr = free_msghdrs; free_msghdrs = msghdr->msg_next; msghdr->msg_spot = -1; msghdr->msg_ts = msgsz; /* * Allocate space for the message */ while (segs_needed > 0) { KASSERT(nfree_msgmaps > 0); KASSERT(free_msgmaps != -1); KASSERT(free_msgmaps < msginfo.msgseg); next = free_msgmaps; MSG_PRINTF(("allocating segment %d to message\n", next)); free_msgmaps = msgmaps[next].next; nfree_msgmaps--; msgmaps[next].next = msghdr->msg_spot; msghdr->msg_spot = next; segs_needed--; } /* * Copy in the message type */ mutex_exit(&msgmutex); error = (*fetch_type)(user_msgp, &msghdr->msg_type, typesz); mutex_enter(&msgmutex); if (error != 0) { MSG_PRINTF(("error %d copying the message type\n", error)); msg_freehdr(msghdr); msqptr->msg_perm.mode &= ~MSG_LOCKED; cv_broadcast(&msq->msq_cv); goto unlock; } user_msgp += typesz; /* * Validate the message type */ if (msghdr->msg_type < 1) { msg_freehdr(msghdr); msqptr->msg_perm.mode &= ~MSG_LOCKED; cv_broadcast(&msq->msq_cv); MSG_PRINTF(("mtype (%ld) < 1\n", msghdr->msg_type)); error = EINVAL; goto unlock; } /* * Copy in the message body */ next = msghdr->msg_spot; while (msgsz > 0) { size_t tlen; KASSERT(next > -1); KASSERT(next < msginfo.msgseg); if (msgsz > msginfo.msgssz) tlen = msginfo.msgssz; else tlen = msgsz; mutex_exit(&msgmutex); error = copyin(user_msgp, &msgpool[next * msginfo.msgssz], tlen); mutex_enter(&msgmutex); if (error != 0) { MSG_PRINTF(("error %d copying in message segment\n", error)); msg_freehdr(msghdr); msqptr->msg_perm.mode &= ~MSG_LOCKED; cv_broadcast(&msq->msq_cv); goto unlock; } msgsz -= tlen; user_msgp += tlen; next = msgmaps[next].next; } KASSERT(next == -1); /* * We've got the message. Unlock the msqid_ds. */ msqptr->msg_perm.mode &= ~MSG_LOCKED; /* * Make sure that the msqid_ds is still allocated. */ if (msqptr->msg_qbytes == 0) { msg_freehdr(msghdr); cv_broadcast(&msq->msq_cv); error = EIDRM; goto unlock; } /* * Put the message into the queue */ if (msqptr->_msg_first == NULL) { msqptr->_msg_first = msghdr; msqptr->_msg_last = msghdr; } else { msqptr->_msg_last->msg_next = msghdr; msqptr->_msg_last = msghdr; } msqptr->_msg_last->msg_next = NULL; msqptr->_msg_cbytes += msghdr->msg_ts; msqptr->msg_qnum++; msqptr->msg_lspid = l->l_proc->p_pid; msqptr->msg_stime = time_second; cv_broadcast(&msq->msq_cv); unlock: mutex_exit(&msgmutex); return error; } int sys_msgrcv(struct lwp *l, const struct sys_msgrcv_args *uap, register_t *retval) { /* { syscallarg(int) msqid; syscallarg(void *) msgp; syscallarg(size_t) msgsz; syscallarg(long) msgtyp; syscallarg(int) msgflg; } */ return msgrcv1(l, SCARG(uap, msqid), SCARG(uap, msgp), SCARG(uap, msgsz), SCARG(uap, msgtyp), SCARG(uap, msgflg), sizeof(long), copyout, retval); } int msgrcv1(struct lwp *l, int msqidr, char *user_msgp, size_t msgsz, long msgtyp, int msgflg, size_t typesz, copyout_t put_type, register_t *retval) { size_t len; kauth_cred_t cred = l->l_cred; struct msqid_ds *msqptr; struct __msg *msghdr; int error = 0, msqid; kmsq_t *msq; short next; MSG_PRINTF(("call to msgrcv(%d, %p, %lld, %ld, %d)\n", msqid, user_msgp, (long long)msgsz, msgtyp, msgflg)); restart: msqid = IPCID_TO_IX(msqidr); mutex_enter(&msgmutex); /* In case of reallocation, we will wait for completion */ while (__predict_false(msg_realloc_state)) cv_wait(&msg_realloc_cv, &msgmutex); if (msqid < 0 || msqid >= msginfo.msgmni) { MSG_PRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqid, msginfo.msgmni)); error = EINVAL; goto unlock; } msq = &msqs[msqid]; msqptr = &msq->msq_u; if (msqptr->msg_qbytes == 0) { MSG_PRINTF(("no such message queue id\n")); error = EINVAL; goto unlock; } if (msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { MSG_PRINTF(("wrong sequence number\n")); error = EINVAL; goto unlock; } if ((error = ipcperm(cred, &msqptr->msg_perm, IPC_R))) { MSG_PRINTF(("requester doesn't have read access\n")); goto unlock; } msghdr = NULL; while (msghdr == NULL) { if (msgtyp == 0) { msghdr = msqptr->_msg_first; if (msghdr != NULL) { if (msgsz < msghdr->msg_ts && (msgflg & MSG_NOERROR) == 0) { MSG_PRINTF(("first msg on the queue " "is too big (want %lld, got %d)\n", (long long)msgsz, msghdr->msg_ts)); error = E2BIG; goto unlock; } if (msqptr->_msg_first == msqptr->_msg_last) { msqptr->_msg_first = NULL; msqptr->_msg_last = NULL; } else { msqptr->_msg_first = msghdr->msg_next; KASSERT(msqptr->_msg_first != NULL); } } } else { struct __msg *previous; struct __msg **prev; for (previous = NULL, prev = &msqptr->_msg_first; (msghdr = *prev) != NULL; previous = msghdr, prev = &msghdr->msg_next) { /* * Is this message's type an exact match or is * this message's type less than or equal to * the absolute value of a negative msgtyp? * Note that the second half of this test can * NEVER be true if msgtyp is positive since * msg_type is always positive! */ if (msgtyp != msghdr->msg_type && msghdr->msg_type > -msgtyp) continue; MSG_PRINTF(("found message type %ld, requested %ld\n", msghdr->msg_type, msgtyp)); if (msgsz < msghdr->msg_ts && (msgflg & MSG_NOERROR) == 0) { MSG_PRINTF(("requested message on the queue " "is too big (want %lld, got %d)\n", (long long)msgsz, msghdr->msg_ts)); error = E2BIG; goto unlock; } *prev = msghdr->msg_next; if (msghdr != msqptr->_msg_last) break; if (previous == NULL) { KASSERT(prev == &msqptr->_msg_first); msqptr->_msg_first = NULL; msqptr->_msg_last = NULL; } else { KASSERT(prev != &msqptr->_msg_first); msqptr->_msg_last = previous; } break; } } /* * We've either extracted the msghdr for the appropriate * message or there isn't one. * If there is one then bail out of this loop. */ if (msghdr != NULL) break; /* * Hmph! No message found. Does the user want to wait? */ if ((msgflg & IPC_NOWAIT) != 0) { MSG_PRINTF(("no appropriate message found (msgtyp=%ld)\n", msgtyp)); error = ENOMSG; goto unlock; } /* * Wait for something to happen */ msg_waiters++; MSG_PRINTF(("msgrcv: goodnight\n")); error = cv_wait_sig(&msq->msq_cv, &msgmutex); MSG_PRINTF(("msgrcv: good morning (error=%d)\n", error)); msg_waiters--; /* * In case of such state, notify reallocator and * restart the call. */ if (msg_realloc_state) { cv_broadcast(&msg_realloc_cv); mutex_exit(&msgmutex); goto restart; } if (error != 0) { MSG_PRINTF(("msgsnd: interrupted system call\n")); error = EINTR; goto unlock; } /* * Make sure that the msq queue still exists */ if (msqptr->msg_qbytes == 0 || msqptr->msg_perm._seq != IPCID_TO_SEQ(msqidr)) { MSG_PRINTF(("msqid deleted\n")); error = EIDRM; goto unlock; } } /* * Return the message to the user. * * First, do the bookkeeping (before we risk being interrupted). */ msqptr->_msg_cbytes -= msghdr->msg_ts; msqptr->msg_qnum--; msqptr->msg_lrpid = l->l_proc->p_pid; msqptr->msg_rtime = time_second; /* * Make msgsz the actual amount that we'll be returning. * Note that this effectively truncates the message if it is too long * (since msgsz is never increased). */ MSG_PRINTF(("found a message, msgsz=%lld, msg_ts=%d\n", (long long)msgsz, msghdr->msg_ts)); if (msgsz > msghdr->msg_ts) msgsz = msghdr->msg_ts; /* * Return the type to the user. */ mutex_exit(&msgmutex); error = (*put_type)(&msghdr->msg_type, user_msgp, typesz); mutex_enter(&msgmutex); if (error != 0) { MSG_PRINTF(("error (%d) copying out message type\n", error)); msg_freehdr(msghdr); cv_broadcast(&msq->msq_cv); goto unlock; } user_msgp += typesz; /* * Return the segments to the user */ next = msghdr->msg_spot; for (len = 0; len < msgsz; len += msginfo.msgssz) { size_t tlen; KASSERT(next > -1); KASSERT(next < msginfo.msgseg); if (msgsz - len > msginfo.msgssz) tlen = msginfo.msgssz; else tlen = msgsz - len; mutex_exit(&msgmutex); error = (*put_type)(&msgpool[next * msginfo.msgssz], user_msgp, tlen); mutex_enter(&msgmutex); if (error != 0) { MSG_PRINTF(("error (%d) copying out message segment\n", error)); msg_freehdr(msghdr); cv_broadcast(&msq->msq_cv); goto unlock; } user_msgp += tlen; next = msgmaps[next].next; } /* * Done, return the actual number of bytes copied out. */ msg_freehdr(msghdr); cv_broadcast(&msq->msq_cv); *retval = msgsz; unlock: mutex_exit(&msgmutex); return error; } /* * Sysctl initialization and nodes. */ static int sysctl_ipc_msgmni(SYSCTLFN_ARGS) { int newsize, error; struct sysctlnode node; node = *rnode; node.sysctl_data = &newsize; newsize = msginfo.msgmni; error = sysctl_lookup(SYSCTLFN_CALL(&node)); if (error || newp == NULL) return error; sysctl_unlock(); error = msgrealloc(newsize, msginfo.msgseg); sysctl_relock(); return error; } static int sysctl_ipc_msgseg(SYSCTLFN_ARGS) { int newsize, error; struct sysctlnode node; node = *rnode; node.sysctl_data = &newsize; newsize = msginfo.msgseg; error = sysctl_lookup(SYSCTLFN_CALL(&node)); if (error || newp == NULL) return error; sysctl_unlock(); error = msgrealloc(msginfo.msgmni, newsize); sysctl_relock(); return error; } SYSCTL_SETUP(sysctl_ipc_msg_setup, "sysctl kern.ipc subtree setup") { const struct sysctlnode *node = NULL; sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "kern", NULL, NULL, 0, NULL, 0, CTL_KERN, CTL_EOL); sysctl_createv(clog, 0, NULL, &node, CTLFLAG_PERMANENT, CTLTYPE_NODE, "ipc", SYSCTL_DESCR("SysV IPC options"), NULL, 0, NULL, 0, CTL_KERN, KERN_SYSVIPC, CTL_EOL); if (node == NULL) return; sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "msgmni", SYSCTL_DESCR("Max number of message queue identifiers"), sysctl_ipc_msgmni, 0, &msginfo.msgmni, 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "msgseg", SYSCTL_DESCR("Max number of number of message segments"), sysctl_ipc_msgseg, 0, &msginfo.msgseg, 0, CTL_CREATE, CTL_EOL); }