/*- * 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. */ /*- * Copyright (c) 2003-2005 McAfee, Inc. * All rights reserved. * * This software was developed for the FreeBSD Project in part by McAfee * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research * program. * * 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 AUTHOR 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 AUTHOR 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. */ #include __FBSDID("$FreeBSD$"); #include "opt_sysvipc.h" #include "opt_mac.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues"); static void msginit(void); static int msgunload(void); static int sysvmsg_modload(struct module *, int, void *); #ifdef MSG_DEBUG #define DPRINTF(a) printf a #else #define DPRINTF(a) #endif static void msg_freehdr(struct msg *msghdr); /* XXX casting to (sy_call_t *) is bogus, as usual. */ static sy_call_t *msgcalls[] = { (sy_call_t *)msgctl, (sy_call_t *)msgget, (sy_call_t *)msgsnd, (sy_call_t *)msgrcv }; #ifndef MSGSSZ #define MSGSSZ 8 /* Each segment must be 2^N long */ #endif #ifndef MSGSEG #define MSGSEG 2048 /* must be less than 32767 */ #endif #define MSGMAX (MSGSSZ*MSGSEG) #ifndef MSGMNB #define MSGMNB 2048 /* max # of bytes in a queue */ #endif #ifndef MSGMNI #define MSGMNI 40 #endif #ifndef MSGTQL #define MSGTQL 40 #endif /* * Based on the configuration parameters described in an SVR2 (yes, two) * config(1m) man page. * * Each message is broken up and stored in segments that are msgssz bytes * long. For efficiency reasons, this should be a power of two. Also, * it doesn't make sense if it is less than 8 or greater than about 256. * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of * two between 8 and 1024 inclusive (and panic's if it isn't). */ struct msginfo msginfo = { MSGMAX, /* max chars in a message */ MSGMNI, /* # of message queue identifiers */ MSGMNB, /* max chars in a queue */ MSGTQL, /* max messages in system */ MSGSSZ, /* size of a message segment */ /* (must be small power of 2 greater than 4) */ MSGSEG /* number of message segments */ }; /* * macros to convert between msqid_ds's and msqid's. * (specific to this implementation) */ #define MSQID(ix,ds) ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000)) #define MSQID_IX(id) ((id) & 0xffff) #define MSQID_SEQ(id) (((id) >> 16) & 0xffff) /* * The rest of this file is specific to this particular implementation. */ struct msgmap { short next; /* next segment in buffer */ /* -1 -> available */ /* 0..(MSGSEG-1) -> index of next segment */ }; #define MSG_LOCKED 01000 /* Is this msqid_ds locked? */ 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 */ static struct msqid_kernel *msqids; /* MSGMNI msqid_kernel struct's */ static struct mtx msq_mtx; /* global mutex for message queues. */ static void msginit() { register int i; TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg); TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz); msginfo.msgmax = msginfo.msgseg * msginfo.msgssz; TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni); TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb); TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql); msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK); if (msgpool == NULL) panic("msgpool is NULL"); msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK); if (msgmaps == NULL) panic("msgmaps is NULL"); msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK); if (msghdrs == NULL) panic("msghdrs is NULL"); msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG, M_WAITOK); if (msqids == NULL) panic("msqids is NULL"); /* * 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) { DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz, msginfo.msgssz)); panic("msginfo.msgssz not a small power of 2"); } if (msginfo.msgseg > 32767) { DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg)); panic("msginfo.msgseg > 32767"); } if (msgmaps == NULL) panic("msgmaps is NULL"); for (i = 0; i < msginfo.msgseg; i++) { if (i > 0) msgmaps[i-1].next = i; msgmaps[i].next = -1; /* implies entry is available */ } free_msgmaps = 0; nfree_msgmaps = msginfo.msgseg; if (msghdrs == NULL) panic("msghdrs is NULL"); for (i = 0; i < msginfo.msgtql; i++) { msghdrs[i].msg_type = 0; if (i > 0) msghdrs[i-1].msg_next = &msghdrs[i]; msghdrs[i].msg_next = NULL; #ifdef MAC mac_sysvmsg_init(&msghdrs[i]); #endif } free_msghdrs = &msghdrs[0]; if (msqids == NULL) panic("msqids is NULL"); for (i = 0; i < msginfo.msgmni; i++) { msqids[i].u.msg_qbytes = 0; /* implies entry is available */ msqids[i].u.msg_perm.seq = 0; /* reset to a known value */ msqids[i].u.msg_perm.mode = 0; #ifdef MAC mac_sysvmsq_init(&msqids[i]); #endif } mtx_init(&msq_mtx, "msq", NULL, MTX_DEF); } static int msgunload() { struct msqid_kernel *msqkptr; int msqid; #ifdef MAC int i; #endif 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. */ msqkptr = &msqids[msqid]; if (msqkptr->u.msg_qbytes != 0 || (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) break; } if (msqid != msginfo.msgmni) return (EBUSY); #ifdef MAC for (i = 0; i < msginfo.msgtql; i++) mac_sysvmsg_destroy(&msghdrs[i]); for (msqid = 0; msqid < msginfo.msgmni; msqid++) mac_sysvmsq_destroy(&msqids[msqid]); #endif free(msgpool, M_MSG); free(msgmaps, M_MSG); free(msghdrs, M_MSG); free(msqids, M_MSG); mtx_destroy(&msq_mtx); return (0); } static int sysvmsg_modload(struct module *module, int cmd, void *arg) { int error = 0; switch (cmd) { case MOD_LOAD: msginit(); break; case MOD_UNLOAD: error = msgunload(); break; case MOD_SHUTDOWN: break; default: error = EINVAL; break; } return (error); } static moduledata_t sysvmsg_mod = { "sysvmsg", &sysvmsg_modload, NULL }; SYSCALL_MODULE_HELPER(msgsys); SYSCALL_MODULE_HELPER(msgctl); SYSCALL_MODULE_HELPER(msgget); SYSCALL_MODULE_HELPER(msgsnd); SYSCALL_MODULE_HELPER(msgrcv); DECLARE_MODULE(sysvmsg, sysvmsg_mod, SI_SUB_SYSV_MSG, SI_ORDER_FIRST); MODULE_VERSION(sysvmsg, 1); /* * Entry point for all MSG calls. */ int msgsys(td, uap) struct thread *td; /* XXX actually varargs. */ struct msgsys_args /* { int which; int a2; int a3; int a4; int a5; int a6; } */ *uap; { int error; if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) return (ENOSYS); if (uap->which < 0 || uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0])) return (EINVAL); error = (*msgcalls[uap->which])(td, &uap->a2); return (error); } static void msg_freehdr(msghdr) struct msg *msghdr; { while (msghdr->msg_ts > 0) { short next; if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg) panic("msghdr->msg_spot out of range"); 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; } if (msghdr->msg_spot != -1) panic("msghdr->msg_spot != -1"); msghdr->msg_next = free_msghdrs; free_msghdrs = msghdr; #ifdef MAC mac_sysvmsg_cleanup(msghdr); #endif } #ifndef _SYS_SYSPROTO_H_ struct msgctl_args { int msqid; int cmd; struct msqid_ds *buf; }; #endif int msgctl(td, uap) struct thread *td; register struct msgctl_args *uap; { int msqid = uap->msqid; int cmd = uap->cmd; struct msqid_ds msqbuf; int error; DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf)); if (cmd == IPC_SET && (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0) return (error); error = kern_msgctl(td, msqid, cmd, &msqbuf); if (cmd == IPC_STAT && error == 0) error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds)); return (error); } int kern_msgctl(td, msqid, cmd, msqbuf) struct thread *td; int msqid; int cmd; struct msqid_ds *msqbuf; { int rval, error, msqix; register struct msqid_kernel *msqkptr; if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) return (ENOSYS); msqix = IPCID_TO_IX(msqid); if (msqix < 0 || msqix >= msginfo.msgmni) { DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix, msginfo.msgmni)); return (EINVAL); } msqkptr = &msqids[msqix]; mtx_lock(&msq_mtx); if (msqkptr->u.msg_qbytes == 0) { DPRINTF(("no such msqid\n")); error = EINVAL; goto done2; } if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) { DPRINTF(("wrong sequence number\n")); error = EINVAL; goto done2; } #ifdef MAC error = mac_sysvmsq_check_msqctl(td->td_ucred, msqkptr, cmd); if (error != 0) goto done2; #endif error = 0; rval = 0; switch (cmd) { case IPC_RMID: { struct msg *msghdr; if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M))) goto done2; #ifdef MAC /* * Check that the thread has MAC access permissions to * individual msghdrs. Note: We need to do this in a * separate loop because the actual loop alters the * msq/msghdr info as it progresses, and there is no going * back if half the way through we discover that the * thread cannot free a certain msghdr. The msq will get * into an inconsistent state. */ for (msghdr = msqkptr->u.msg_first; msghdr != NULL; msghdr = msghdr->msg_next) { error = mac_sysvmsq_check_msgrmid(td->td_ucred, msghdr); if (error != 0) goto done2; } #endif /* Free the message headers */ msghdr = msqkptr->u.msg_first; while (msghdr != NULL) { struct msg *msghdr_tmp; /* Free the segments of each message */ msqkptr->u.msg_cbytes -= msghdr->msg_ts; msqkptr->u.msg_qnum--; msghdr_tmp = msghdr; msghdr = msghdr->msg_next; msg_freehdr(msghdr_tmp); } if (msqkptr->u.msg_cbytes != 0) panic("msg_cbytes is screwed up"); if (msqkptr->u.msg_qnum != 0) panic("msg_qnum is screwed up"); msqkptr->u.msg_qbytes = 0; /* Mark it as free */ #ifdef MAC mac_sysvmsq_cleanup(msqkptr); #endif wakeup(msqkptr); } break; case IPC_SET: if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M))) goto done2; if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) { error = priv_check(td, PRIV_IPC_MSGSIZE); if (error) goto done2; } if (msqbuf->msg_qbytes > msginfo.msgmnb) { DPRINTF(("can't increase msg_qbytes beyond %d" "(truncating)\n", msginfo.msgmnb)); msqbuf->msg_qbytes = msginfo.msgmnb; /* silently restrict qbytes to system limit */ } if (msqbuf->msg_qbytes == 0) { DPRINTF(("can't reduce msg_qbytes to 0\n")); error = EINVAL; /* non-standard errno! */ goto done2; } msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */ msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */ msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) | (msqbuf->msg_perm.mode & 0777); msqkptr->u.msg_qbytes = msqbuf->msg_qbytes; msqkptr->u.msg_ctime = time_second; break; case IPC_STAT: if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) { DPRINTF(("requester doesn't have read access\n")); goto done2; } *msqbuf = msqkptr->u; break; default: DPRINTF(("invalid command %d\n", cmd)); error = EINVAL; goto done2; } if (error == 0) td->td_retval[0] = rval; done2: mtx_unlock(&msq_mtx); return (error); } #ifndef _SYS_SYSPROTO_H_ struct msgget_args { key_t key; int msgflg; }; #endif int msgget(td, uap) struct thread *td; register struct msgget_args *uap; { int msqid, error = 0; int key = uap->key; int msgflg = uap->msgflg; struct ucred *cred = td->td_ucred; register struct msqid_kernel *msqkptr = NULL; DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg)); if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) return (ENOSYS); mtx_lock(&msq_mtx); if (key != IPC_PRIVATE) { for (msqid = 0; msqid < msginfo.msgmni; msqid++) { msqkptr = &msqids[msqid]; if (msqkptr->u.msg_qbytes != 0 && msqkptr->u.msg_perm.key == key) break; } if (msqid < msginfo.msgmni) { DPRINTF(("found public key\n")); if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) { DPRINTF(("not exclusive\n")); error = EEXIST; goto done2; } if ((error = ipcperm(td, &msqkptr->u.msg_perm, msgflg & 0700))) { DPRINTF(("requester doesn't have 0%o access\n", msgflg & 0700)); goto done2; } #ifdef MAC error = mac_sysvmsq_check_msqget(cred, msqkptr); if (error != 0) goto done2; #endif goto found; } } DPRINTF(("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. */ msqkptr = &msqids[msqid]; if (msqkptr->u.msg_qbytes == 0 && (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0) break; } if (msqid == msginfo.msgmni) { DPRINTF(("no more msqid_ds's available\n")); error = ENOSPC; goto done2; } DPRINTF(("msqid %d is available\n", msqid)); msqkptr->u.msg_perm.key = key; msqkptr->u.msg_perm.cuid = cred->cr_uid; msqkptr->u.msg_perm.uid = cred->cr_uid; msqkptr->u.msg_perm.cgid = cred->cr_gid; msqkptr->u.msg_perm.gid = cred->cr_gid; msqkptr->u.msg_perm.mode = (msgflg & 0777); /* Make sure that the returned msqid is unique */ msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff; msqkptr->u.msg_first = NULL; msqkptr->u.msg_last = NULL; msqkptr->u.msg_cbytes = 0; msqkptr->u.msg_qnum = 0; msqkptr->u.msg_qbytes = msginfo.msgmnb; msqkptr->u.msg_lspid = 0; msqkptr->u.msg_lrpid = 0; msqkptr->u.msg_stime = 0; msqkptr->u.msg_rtime = 0; msqkptr->u.msg_ctime = time_second; #ifdef MAC mac_sysvmsq_create(cred, msqkptr); #endif } else { DPRINTF(("didn't find it and wasn't asked to create it\n")); error = ENOENT; goto done2; } found: /* Construct the unique msqid */ td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm); done2: mtx_unlock(&msq_mtx); return (error); } #ifndef _SYS_SYSPROTO_H_ struct msgsnd_args { int msqid; const void *msgp; size_t msgsz; int msgflg; }; #endif int kern_msgsnd(td, msqid, msgp, msgsz, msgflg, mtype) struct thread *td; int msqid; const void *msgp; /* XXX msgp is actually mtext. */ size_t msgsz; int msgflg; long mtype; { int msqix, segs_needed, error = 0; register struct msqid_kernel *msqkptr; register struct msg *msghdr; short next; if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) return (ENOSYS); mtx_lock(&msq_mtx); msqix = IPCID_TO_IX(msqid); if (msqix < 0 || msqix >= msginfo.msgmni) { DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix, msginfo.msgmni)); error = EINVAL; goto done2; } msqkptr = &msqids[msqix]; if (msqkptr->u.msg_qbytes == 0) { DPRINTF(("no such message queue id\n")); error = EINVAL; goto done2; } if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) { DPRINTF(("wrong sequence number\n")); error = EINVAL; goto done2; } if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) { DPRINTF(("requester doesn't have write access\n")); goto done2; } #ifdef MAC error = mac_sysvmsq_check_msqsnd(td->td_ucred, msqkptr); if (error != 0) goto done2; #endif segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz; DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz, msginfo.msgssz, segs_needed)); for (;;) { int need_more_resources = 0; /* * check msgsz * (inside this loop in case msg_qbytes changes while we sleep) */ if (msgsz > msqkptr->u.msg_qbytes) { DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n")); error = EINVAL; goto done2; } if (msqkptr->u.msg_perm.mode & MSG_LOCKED) { DPRINTF(("msqid is locked\n")); need_more_resources = 1; } if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) { DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n")); need_more_resources = 1; } if (segs_needed > nfree_msgmaps) { DPRINTF(("segs_needed > nfree_msgmaps\n")); need_more_resources = 1; } if (free_msghdrs == NULL) { DPRINTF(("no more msghdrs\n")); need_more_resources = 1; } if (need_more_resources) { int we_own_it; if ((msgflg & IPC_NOWAIT) != 0) { DPRINTF(("need more resources but caller " "doesn't want to wait\n")); error = EAGAIN; goto done2; } if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) { DPRINTF(("we don't own the msqid_ds\n")); we_own_it = 0; } else { /* Force later arrivals to wait for our request */ DPRINTF(("we own the msqid_ds\n")); msqkptr->u.msg_perm.mode |= MSG_LOCKED; we_own_it = 1; } DPRINTF(("msgsnd: goodnight\n")); error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH, "msgsnd", hz); DPRINTF(("msgsnd: good morning, error=%d\n", error)); if (we_own_it) msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; if (error == EWOULDBLOCK) { DPRINTF(("msgsnd: timed out\n")); continue; } if (error != 0) { DPRINTF(("msgsnd: interrupted system call\n")); error = EINTR; goto done2; } /* * Make sure that the msq queue still exists */ if (msqkptr->u.msg_qbytes == 0) { DPRINTF(("msqid deleted\n")); error = EIDRM; goto done2; } } else { DPRINTF(("got all the resources that we need\n")); break; } } /* * We have the resources that we need. * Make sure! */ if (msqkptr->u.msg_perm.mode & MSG_LOCKED) panic("msg_perm.mode & MSG_LOCKED"); if (segs_needed > nfree_msgmaps) panic("segs_needed > nfree_msgmaps"); if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) panic("msgsz + msg_cbytes > msg_qbytes"); if (free_msghdrs == NULL) panic("no more msghdrs"); /* * Re-lock the msqid_ds in case we page-fault when copying in the * message */ if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) panic("msqid_ds is already locked"); msqkptr->u.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; msghdr->msg_type = mtype; #ifdef MAC /* * XXXMAC: Should the mac_sysvmsq_check_msgmsq check follow here * immediately? Or, should it be checked just before the msg is * enqueued in the msgq (as it is done now)? */ mac_sysvmsg_create(td->td_ucred, msqkptr, msghdr); #endif /* * Allocate space for the message */ while (segs_needed > 0) { if (nfree_msgmaps <= 0) panic("not enough msgmaps"); if (free_msgmaps == -1) panic("nil free_msgmaps"); next = free_msgmaps; if (next <= -1) panic("next too low #1"); if (next >= msginfo.msgseg) panic("next out of range #1"); DPRINTF(("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--; } /* * Validate the message type */ if (msghdr->msg_type < 1) { msg_freehdr(msghdr); msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; wakeup(msqkptr); DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type)); error = EINVAL; goto done2; } /* * Copy in the message body */ next = msghdr->msg_spot; while (msgsz > 0) { size_t tlen; if (msgsz > msginfo.msgssz) tlen = msginfo.msgssz; else tlen = msgsz; if (next <= -1) panic("next too low #2"); if (next >= msginfo.msgseg) panic("next out of range #2"); mtx_unlock(&msq_mtx); if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz], tlen)) != 0) { mtx_lock(&msq_mtx); DPRINTF(("error %d copying in message segment\n", error)); msg_freehdr(msghdr); msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; wakeup(msqkptr); goto done2; } mtx_lock(&msq_mtx); msgsz -= tlen; msgp = (const char *)msgp + tlen; next = msgmaps[next].next; } if (next != -1) panic("didn't use all the msg segments"); /* * We've got the message. Unlock the msqid_ds. */ msqkptr->u.msg_perm.mode &= ~MSG_LOCKED; /* * Make sure that the msqid_ds is still allocated. */ if (msqkptr->u.msg_qbytes == 0) { msg_freehdr(msghdr); wakeup(msqkptr); error = EIDRM; goto done2; } #ifdef MAC /* * Note: Since the task/thread allocates the msghdr and usually * primes it with its own MAC label, for a majority of policies, it * won't be necessary to check whether the msghdr has access * permissions to the msgq. The mac_sysvmsq_check_msqsnd check would * suffice in that case. However, this hook may be required where * individual policies derive a non-identical label for the msghdr * from the current thread label and may want to check the msghdr * enqueue permissions, along with read/write permissions to the * msgq. */ error = mac_sysvmsq_check_msgmsq(td->td_ucred, msghdr, msqkptr); if (error != 0) { msg_freehdr(msghdr); wakeup(msqkptr); goto done2; } #endif /* * Put the message into the queue */ if (msqkptr->u.msg_first == NULL) { msqkptr->u.msg_first = msghdr; msqkptr->u.msg_last = msghdr; } else { msqkptr->u.msg_last->msg_next = msghdr; msqkptr->u.msg_last = msghdr; } msqkptr->u.msg_last->msg_next = NULL; msqkptr->u.msg_cbytes += msghdr->msg_ts; msqkptr->u.msg_qnum++; msqkptr->u.msg_lspid = td->td_proc->p_pid; msqkptr->u.msg_stime = time_second; wakeup(msqkptr); td->td_retval[0] = 0; done2: mtx_unlock(&msq_mtx); return (error); } int msgsnd(td, uap) struct thread *td; register struct msgsnd_args *uap; { int error; long mtype; DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp, uap->msgsz, uap->msgflg)); if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) { DPRINTF(("error %d copying the message type\n", error)); return (error); } return (kern_msgsnd(td, uap->msqid, (const char *)uap->msgp + sizeof(mtype), uap->msgsz, uap->msgflg, mtype)); } #ifndef _SYS_SYSPROTO_H_ struct msgrcv_args { int msqid; void *msgp; size_t msgsz; long msgtyp; int msgflg; }; #endif int kern_msgrcv(td, msqid, msgp, msgsz, msgtyp, msgflg, mtype) struct thread *td; int msqid; void *msgp; /* XXX msgp is actually mtext. */ size_t msgsz; long msgtyp; int msgflg; long *mtype; { size_t len; register struct msqid_kernel *msqkptr; register struct msg *msghdr; int msqix, error = 0; short next; if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC)) return (ENOSYS); msqix = IPCID_TO_IX(msqid); if (msqix < 0 || msqix >= msginfo.msgmni) { DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix, msginfo.msgmni)); return (EINVAL); } msqkptr = &msqids[msqix]; mtx_lock(&msq_mtx); if (msqkptr->u.msg_qbytes == 0) { DPRINTF(("no such message queue id\n")); error = EINVAL; goto done2; } if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) { DPRINTF(("wrong sequence number\n")); error = EINVAL; goto done2; } if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) { DPRINTF(("requester doesn't have read access\n")); goto done2; } #ifdef MAC error = mac_sysvmsq_check_msqrcv(td->td_ucred, msqkptr); if (error != 0) goto done2; #endif msghdr = NULL; while (msghdr == NULL) { if (msgtyp == 0) { msghdr = msqkptr->u.msg_first; if (msghdr != NULL) { if (msgsz < msghdr->msg_ts && (msgflg & MSG_NOERROR) == 0) { DPRINTF(("first message on the queue " "is too big (want %zu, got %d)\n", msgsz, msghdr->msg_ts)); error = E2BIG; goto done2; } #ifdef MAC error = mac_sysvmsq_check_msgrcv(td->td_ucred, msghdr); if (error != 0) goto done2; #endif if (msqkptr->u.msg_first == msqkptr->u.msg_last) { msqkptr->u.msg_first = NULL; msqkptr->u.msg_last = NULL; } else { msqkptr->u.msg_first = msghdr->msg_next; if (msqkptr->u.msg_first == NULL) panic("msg_first/last screwed up #1"); } } } else { struct msg *previous; struct msg **prev; previous = NULL; prev = &(msqkptr->u.msg_first); while ((msghdr = *prev) != NULL) { /* * 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) { DPRINTF(("found message type %ld, " "requested %ld\n", msghdr->msg_type, msgtyp)); if (msgsz < msghdr->msg_ts && (msgflg & MSG_NOERROR) == 0) { DPRINTF(("requested message " "on the queue is too big " "(want %zu, got %hu)\n", msgsz, msghdr->msg_ts)); error = E2BIG; goto done2; } #ifdef MAC error = mac_sysvmsq_check_msgrcv( td->td_ucred, msghdr); if (error != 0) goto done2; #endif *prev = msghdr->msg_next; if (msghdr == msqkptr->u.msg_last) { if (previous == NULL) { if (prev != &msqkptr->u.msg_first) panic("msg_first/last screwed up #2"); msqkptr->u.msg_first = NULL; msqkptr->u.msg_last = NULL; } else { if (prev == &msqkptr->u.msg_first) panic("msg_first/last screwed up #3"); msqkptr->u.msg_last = previous; } } break; } previous = msghdr; prev = &(msghdr->msg_next); } } /* * 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) { DPRINTF(("no appropriate message found (msgtyp=%ld)\n", msgtyp)); /* The SVID says to return ENOMSG. */ error = ENOMSG; goto done2; } /* * Wait for something to happen */ DPRINTF(("msgrcv: goodnight\n")); error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH, "msgrcv", 0); DPRINTF(("msgrcv: good morning (error=%d)\n", error)); if (error != 0) { DPRINTF(("msgrcv: interrupted system call\n")); error = EINTR; goto done2; } /* * Make sure that the msq queue still exists */ if (msqkptr->u.msg_qbytes == 0 || msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) { DPRINTF(("msqid deleted\n")); error = EIDRM; goto done2; } } /* * Return the message to the user. * * First, do the bookkeeping (before we risk being interrupted). */ msqkptr->u.msg_cbytes -= msghdr->msg_ts; msqkptr->u.msg_qnum--; msqkptr->u.msg_lrpid = td->td_proc->p_pid; msqkptr->u.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). */ DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz, msghdr->msg_ts)); if (msgsz > msghdr->msg_ts) msgsz = msghdr->msg_ts; *mtype = msghdr->msg_type; /* * Return the segments to the user */ next = msghdr->msg_spot; for (len = 0; len < msgsz; len += msginfo.msgssz) { size_t tlen; if (msgsz - len > msginfo.msgssz) tlen = msginfo.msgssz; else tlen = msgsz - len; if (next <= -1) panic("next too low #3"); if (next >= msginfo.msgseg) panic("next out of range #3"); mtx_unlock(&msq_mtx); error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen); mtx_lock(&msq_mtx); if (error != 0) { DPRINTF(("error (%d) copying out message segment\n", error)); msg_freehdr(msghdr); wakeup(msqkptr); goto done2; } msgp = (char *)msgp + tlen; next = msgmaps[next].next; } /* * Done, return the actual number of bytes copied out. */ msg_freehdr(msghdr); wakeup(msqkptr); td->td_retval[0] = msgsz; done2: mtx_unlock(&msq_mtx); return (error); } int msgrcv(td, uap) struct thread *td; register struct msgrcv_args *uap; { int error; long mtype; DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid, uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg)); if ((error = kern_msgrcv(td, uap->msqid, (char *)uap->msgp + sizeof(mtype), uap->msgsz, uap->msgtyp, uap->msgflg, &mtype)) != 0) return (error); if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0) DPRINTF(("error %d copying the message type\n", error)); return (error); } static int sysctl_msqids(SYSCTL_HANDLER_ARGS) { return (SYSCTL_OUT(req, msqids, sizeof(struct msqid_kernel) * msginfo.msgmni)); } SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0, "Maximum message size"); SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0, "Number of message queue identifiers"); SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0, "Maximum number of bytes in a queue"); SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0, "Maximum number of messages in the system"); SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0, "Size of a message segment"); SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0, "Number of message segments"); SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLFLAG_RD, NULL, 0, sysctl_msqids, "", "Message queue IDs");