The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/kern/sysv_msg.c

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    1 /*-
    2  * Implementation of SVID messages
    3  *
    4  * Author:  Daniel Boulet
    5  *
    6  * Copyright 1993 Daniel Boulet and RTMX Inc.
    7  *
    8  * This system call was implemented by Daniel Boulet under contract from RTMX.
    9  *
   10  * Redistribution and use in source forms, with and without modification,
   11  * are permitted provided that this entire comment appears intact.
   12  *
   13  * Redistribution in binary form may occur without any restrictions.
   14  * Obviously, it would be nice if you gave credit where credit is due
   15  * but requiring it would be too onerous.
   16  *
   17  * This software is provided ``AS IS'' without any warranties of any kind.
   18  */
   19 /*-
   20  * Copyright (c) 2003-2005 McAfee, Inc.
   21  * All rights reserved.
   22  *
   23  * This software was developed for the FreeBSD Project in part by McAfee
   24  * Research, the Security Research Division of McAfee, Inc under DARPA/SPAWAR
   25  * contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS research
   26  * program.
   27  *
   28  * Redistribution and use in source and binary forms, with or without
   29  * modification, are permitted provided that the following conditions
   30  * are met:
   31  * 1. Redistributions of source code must retain the above copyright
   32  *    notice, this list of conditions and the following disclaimer.
   33  * 2. Redistributions in binary form must reproduce the above copyright
   34  *    notice, this list of conditions and the following disclaimer in the
   35  *    documentation and/or other materials provided with the distribution.
   36  *
   37  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   38  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   39  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   40  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   41  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   42  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   43  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   45  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   46  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   47  * SUCH DAMAGE.
   48  */
   49 
   50 #include <sys/cdefs.h>
   51 __FBSDID("$FreeBSD: releng/9.0/sys/kern/sysv_msg.c 225617 2011-09-16 13:58:51Z kmacy $");
   52 
   53 #include "opt_compat.h"
   54 #include "opt_sysvipc.h"
   55 
   56 #include <sys/param.h>
   57 #include <sys/systm.h>
   58 #include <sys/sysproto.h>
   59 #include <sys/kernel.h>
   60 #include <sys/priv.h>
   61 #include <sys/proc.h>
   62 #include <sys/lock.h>
   63 #include <sys/mutex.h>
   64 #include <sys/module.h>
   65 #include <sys/msg.h>
   66 #include <sys/racct.h>
   67 #include <sys/syscall.h>
   68 #include <sys/syscallsubr.h>
   69 #include <sys/sysent.h>
   70 #include <sys/sysctl.h>
   71 #include <sys/malloc.h>
   72 #include <sys/jail.h>
   73 
   74 #include <security/mac/mac_framework.h>
   75 
   76 FEATURE(sysv_msg, "System V message queues support");
   77 
   78 static MALLOC_DEFINE(M_MSG, "msg", "SVID compatible message queues");
   79 
   80 static int msginit(void);
   81 static int msgunload(void);
   82 static int sysvmsg_modload(struct module *, int, void *);
   83 
   84 
   85 #ifdef MSG_DEBUG
   86 #define DPRINTF(a)      printf a
   87 #else
   88 #define DPRINTF(a)      (void)0
   89 #endif
   90 
   91 static void msg_freehdr(struct msg *msghdr);
   92 
   93 #ifndef MSGSSZ
   94 #define MSGSSZ  8               /* Each segment must be 2^N long */
   95 #endif
   96 #ifndef MSGSEG
   97 #define MSGSEG  2048            /* must be less than 32767 */
   98 #endif
   99 #define MSGMAX  (MSGSSZ*MSGSEG)
  100 #ifndef MSGMNB
  101 #define MSGMNB  2048            /* max # of bytes in a queue */
  102 #endif
  103 #ifndef MSGMNI
  104 #define MSGMNI  40
  105 #endif
  106 #ifndef MSGTQL
  107 #define MSGTQL  40
  108 #endif
  109 
  110 /*
  111  * Based on the configuration parameters described in an SVR2 (yes, two)
  112  * config(1m) man page.
  113  *
  114  * Each message is broken up and stored in segments that are msgssz bytes
  115  * long.  For efficiency reasons, this should be a power of two.  Also,
  116  * it doesn't make sense if it is less than 8 or greater than about 256.
  117  * Consequently, msginit in kern/sysv_msg.c checks that msgssz is a power of
  118  * two between 8 and 1024 inclusive (and panic's if it isn't).
  119  */
  120 struct msginfo msginfo = {
  121                 MSGMAX,         /* max chars in a message */
  122                 MSGMNI,         /* # of message queue identifiers */
  123                 MSGMNB,         /* max chars in a queue */
  124                 MSGTQL,         /* max messages in system */
  125                 MSGSSZ,         /* size of a message segment */
  126                                 /* (must be small power of 2 greater than 4) */
  127                 MSGSEG          /* number of message segments */
  128 };
  129 
  130 /*
  131  * macros to convert between msqid_ds's and msqid's.
  132  * (specific to this implementation)
  133  */
  134 #define MSQID(ix,ds)    ((ix) & 0xffff | (((ds).msg_perm.seq << 16) & 0xffff0000))
  135 #define MSQID_IX(id)    ((id) & 0xffff)
  136 #define MSQID_SEQ(id)   (((id) >> 16) & 0xffff)
  137 
  138 /*
  139  * The rest of this file is specific to this particular implementation.
  140  */
  141 
  142 struct msgmap {
  143         short   next;           /* next segment in buffer */
  144                                 /* -1 -> available */
  145                                 /* 0..(MSGSEG-1) -> index of next segment */
  146 };
  147 
  148 #define MSG_LOCKED      01000   /* Is this msqid_ds locked? */
  149 
  150 static int nfree_msgmaps;       /* # of free map entries */
  151 static short free_msgmaps;      /* head of linked list of free map entries */
  152 static struct msg *free_msghdrs;/* list of free msg headers */
  153 static char *msgpool;           /* MSGMAX byte long msg buffer pool */
  154 static struct msgmap *msgmaps;  /* MSGSEG msgmap structures */
  155 static struct msg *msghdrs;     /* MSGTQL msg headers */
  156 static struct msqid_kernel *msqids;     /* MSGMNI msqid_kernel struct's */
  157 static struct mtx msq_mtx;      /* global mutex for message queues. */
  158 
  159 static struct syscall_helper_data msg_syscalls[] = {
  160         SYSCALL_INIT_HELPER(msgctl),
  161         SYSCALL_INIT_HELPER(msgget),
  162         SYSCALL_INIT_HELPER(msgsnd),
  163         SYSCALL_INIT_HELPER(msgrcv),
  164 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
  165     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
  166         SYSCALL_INIT_HELPER(msgsys),
  167         SYSCALL_INIT_HELPER_COMPAT(freebsd7_msgctl),
  168 #endif
  169         SYSCALL_INIT_LAST
  170 };
  171 
  172 #ifdef COMPAT_FREEBSD32
  173 #include <compat/freebsd32/freebsd32.h>
  174 #include <compat/freebsd32/freebsd32_ipc.h>
  175 #include <compat/freebsd32/freebsd32_proto.h>
  176 #include <compat/freebsd32/freebsd32_signal.h>
  177 #include <compat/freebsd32/freebsd32_syscall.h>
  178 #include <compat/freebsd32/freebsd32_util.h>
  179 
  180 static struct syscall_helper_data msg32_syscalls[] = {
  181         SYSCALL32_INIT_HELPER(freebsd32_msgctl),
  182         SYSCALL32_INIT_HELPER(freebsd32_msgsnd),
  183         SYSCALL32_INIT_HELPER(freebsd32_msgrcv),
  184         SYSCALL32_INIT_HELPER_COMPAT(msgget),
  185         SYSCALL32_INIT_HELPER(freebsd32_msgsys),
  186 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
  187     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
  188         SYSCALL32_INIT_HELPER(freebsd7_freebsd32_msgctl),
  189 #endif
  190         SYSCALL_INIT_LAST
  191 };
  192 #endif
  193 
  194 static int
  195 msginit()
  196 {
  197         int i, error;
  198 
  199         TUNABLE_INT_FETCH("kern.ipc.msgseg", &msginfo.msgseg);
  200         TUNABLE_INT_FETCH("kern.ipc.msgssz", &msginfo.msgssz);
  201         msginfo.msgmax = msginfo.msgseg * msginfo.msgssz;
  202         TUNABLE_INT_FETCH("kern.ipc.msgmni", &msginfo.msgmni);
  203         TUNABLE_INT_FETCH("kern.ipc.msgmnb", &msginfo.msgmnb);
  204         TUNABLE_INT_FETCH("kern.ipc.msgtql", &msginfo.msgtql);
  205 
  206         msgpool = malloc(msginfo.msgmax, M_MSG, M_WAITOK);
  207         msgmaps = malloc(sizeof(struct msgmap) * msginfo.msgseg, M_MSG, M_WAITOK);
  208         msghdrs = malloc(sizeof(struct msg) * msginfo.msgtql, M_MSG, M_WAITOK);
  209         msqids = malloc(sizeof(struct msqid_kernel) * msginfo.msgmni, M_MSG,
  210             M_WAITOK);
  211 
  212         /*
  213          * msginfo.msgssz should be a power of two for efficiency reasons.
  214          * It is also pretty silly if msginfo.msgssz is less than 8
  215          * or greater than about 256 so ...
  216          */
  217 
  218         i = 8;
  219         while (i < 1024 && i != msginfo.msgssz)
  220                 i <<= 1;
  221         if (i != msginfo.msgssz) {
  222                 DPRINTF(("msginfo.msgssz=%d (0x%x)\n", msginfo.msgssz,
  223                     msginfo.msgssz));
  224                 panic("msginfo.msgssz not a small power of 2");
  225         }
  226 
  227         if (msginfo.msgseg > 32767) {
  228                 DPRINTF(("msginfo.msgseg=%d\n", msginfo.msgseg));
  229                 panic("msginfo.msgseg > 32767");
  230         }
  231 
  232         for (i = 0; i < msginfo.msgseg; i++) {
  233                 if (i > 0)
  234                         msgmaps[i-1].next = i;
  235                 msgmaps[i].next = -1;   /* implies entry is available */
  236         }
  237         free_msgmaps = 0;
  238         nfree_msgmaps = msginfo.msgseg;
  239 
  240         for (i = 0; i < msginfo.msgtql; i++) {
  241                 msghdrs[i].msg_type = 0;
  242                 if (i > 0)
  243                         msghdrs[i-1].msg_next = &msghdrs[i];
  244                 msghdrs[i].msg_next = NULL;
  245 #ifdef MAC
  246                 mac_sysvmsg_init(&msghdrs[i]);
  247 #endif
  248         }
  249         free_msghdrs = &msghdrs[0];
  250 
  251         for (i = 0; i < msginfo.msgmni; i++) {
  252                 msqids[i].u.msg_qbytes = 0;     /* implies entry is available */
  253                 msqids[i].u.msg_perm.seq = 0;   /* reset to a known value */
  254                 msqids[i].u.msg_perm.mode = 0;
  255 #ifdef MAC
  256                 mac_sysvmsq_init(&msqids[i]);
  257 #endif
  258         }
  259         mtx_init(&msq_mtx, "msq", NULL, MTX_DEF);
  260 
  261         error = syscall_helper_register(msg_syscalls);
  262         if (error != 0)
  263                 return (error);
  264 #ifdef COMPAT_FREEBSD32
  265         error = syscall32_helper_register(msg32_syscalls);
  266         if (error != 0)
  267                 return (error);
  268 #endif
  269         return (0);
  270 }
  271 
  272 static int
  273 msgunload()
  274 {
  275         struct msqid_kernel *msqkptr;
  276         int msqid;
  277 #ifdef MAC
  278         int i;
  279 #endif
  280 
  281         syscall_helper_unregister(msg_syscalls);
  282 #ifdef COMPAT_FREEBSD32
  283         syscall32_helper_unregister(msg32_syscalls);
  284 #endif
  285 
  286         for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
  287                 /*
  288                  * Look for an unallocated and unlocked msqid_ds.
  289                  * msqid_ds's can be locked by msgsnd or msgrcv while
  290                  * they are copying the message in/out.  We can't
  291                  * re-use the entry until they release it.
  292                  */
  293                 msqkptr = &msqids[msqid];
  294                 if (msqkptr->u.msg_qbytes != 0 ||
  295                     (msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
  296                         break;
  297         }
  298         if (msqid != msginfo.msgmni)
  299                 return (EBUSY);
  300 
  301 #ifdef MAC
  302         for (i = 0; i < msginfo.msgtql; i++)
  303                 mac_sysvmsg_destroy(&msghdrs[i]);
  304         for (msqid = 0; msqid < msginfo.msgmni; msqid++)
  305                 mac_sysvmsq_destroy(&msqids[msqid]);
  306 #endif
  307         free(msgpool, M_MSG);
  308         free(msgmaps, M_MSG);
  309         free(msghdrs, M_MSG);
  310         free(msqids, M_MSG);
  311         mtx_destroy(&msq_mtx);
  312         return (0);
  313 }
  314 
  315 
  316 static int
  317 sysvmsg_modload(struct module *module, int cmd, void *arg)
  318 {
  319         int error = 0;
  320 
  321         switch (cmd) {
  322         case MOD_LOAD:
  323                 error = msginit();
  324                 if (error != 0)
  325                         msgunload();
  326                 break;
  327         case MOD_UNLOAD:
  328                 error = msgunload();
  329                 break;
  330         case MOD_SHUTDOWN:
  331                 break;
  332         default:
  333                 error = EINVAL;
  334                 break;
  335         }
  336         return (error);
  337 }
  338 
  339 static moduledata_t sysvmsg_mod = {
  340         "sysvmsg",
  341         &sysvmsg_modload,
  342         NULL
  343 };
  344 
  345 DECLARE_MODULE(sysvmsg, sysvmsg_mod, SI_SUB_SYSV_MSG, SI_ORDER_FIRST);
  346 MODULE_VERSION(sysvmsg, 1);
  347 
  348 static void
  349 msg_freehdr(msghdr)
  350         struct msg *msghdr;
  351 {
  352         while (msghdr->msg_ts > 0) {
  353                 short next;
  354                 if (msghdr->msg_spot < 0 || msghdr->msg_spot >= msginfo.msgseg)
  355                         panic("msghdr->msg_spot out of range");
  356                 next = msgmaps[msghdr->msg_spot].next;
  357                 msgmaps[msghdr->msg_spot].next = free_msgmaps;
  358                 free_msgmaps = msghdr->msg_spot;
  359                 nfree_msgmaps++;
  360                 msghdr->msg_spot = next;
  361                 if (msghdr->msg_ts >= msginfo.msgssz)
  362                         msghdr->msg_ts -= msginfo.msgssz;
  363                 else
  364                         msghdr->msg_ts = 0;
  365         }
  366         if (msghdr->msg_spot != -1)
  367                 panic("msghdr->msg_spot != -1");
  368         msghdr->msg_next = free_msghdrs;
  369         free_msghdrs = msghdr;
  370 #ifdef MAC
  371         mac_sysvmsg_cleanup(msghdr);
  372 #endif
  373 }
  374 
  375 #ifndef _SYS_SYSPROTO_H_
  376 struct msgctl_args {
  377         int     msqid;
  378         int     cmd;
  379         struct  msqid_ds *buf;
  380 };
  381 #endif
  382 int
  383 sys_msgctl(td, uap)
  384         struct thread *td;
  385         register struct msgctl_args *uap;
  386 {
  387         int msqid = uap->msqid;
  388         int cmd = uap->cmd;
  389         struct msqid_ds msqbuf;
  390         int error;
  391 
  392         DPRINTF(("call to msgctl(%d, %d, %p)\n", msqid, cmd, uap->buf));
  393         if (cmd == IPC_SET &&
  394             (error = copyin(uap->buf, &msqbuf, sizeof(msqbuf))) != 0)
  395                 return (error);
  396         error = kern_msgctl(td, msqid, cmd, &msqbuf);
  397         if (cmd == IPC_STAT && error == 0)
  398                 error = copyout(&msqbuf, uap->buf, sizeof(struct msqid_ds));
  399         return (error);
  400 }
  401 
  402 int
  403 kern_msgctl(td, msqid, cmd, msqbuf)
  404         struct thread *td;
  405         int msqid;
  406         int cmd;
  407         struct msqid_ds *msqbuf;
  408 {
  409         int rval, error, msqix;
  410         register struct msqid_kernel *msqkptr;
  411 
  412         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  413                 return (ENOSYS);
  414 
  415         msqix = IPCID_TO_IX(msqid);
  416 
  417         if (msqix < 0 || msqix >= msginfo.msgmni) {
  418                 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
  419                     msginfo.msgmni));
  420                 return (EINVAL);
  421         }
  422 
  423         msqkptr = &msqids[msqix];
  424 
  425         mtx_lock(&msq_mtx);
  426         if (msqkptr->u.msg_qbytes == 0) {
  427                 DPRINTF(("no such msqid\n"));
  428                 error = EINVAL;
  429                 goto done2;
  430         }
  431         if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
  432                 DPRINTF(("wrong sequence number\n"));
  433                 error = EINVAL;
  434                 goto done2;
  435         }
  436 #ifdef MAC
  437         error = mac_sysvmsq_check_msqctl(td->td_ucred, msqkptr, cmd);
  438         if (error != 0)
  439                 goto done2;
  440 #endif
  441 
  442         error = 0;
  443         rval = 0;
  444 
  445         switch (cmd) {
  446 
  447         case IPC_RMID:
  448         {
  449                 struct msg *msghdr;
  450                 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
  451                         goto done2;
  452 
  453 #ifdef MAC
  454                 /*
  455                  * Check that the thread has MAC access permissions to
  456                  * individual msghdrs.  Note: We need to do this in a
  457                  * separate loop because the actual loop alters the
  458                  * msq/msghdr info as it progresses, and there is no going
  459                  * back if half the way through we discover that the
  460                  * thread cannot free a certain msghdr.  The msq will get
  461                  * into an inconsistent state.
  462                  */
  463                 for (msghdr = msqkptr->u.msg_first; msghdr != NULL;
  464                     msghdr = msghdr->msg_next) {
  465                         error = mac_sysvmsq_check_msgrmid(td->td_ucred, msghdr);
  466                         if (error != 0)
  467                                 goto done2;
  468                 }
  469 #endif
  470 
  471                 racct_sub_cred(msqkptr->cred, RACCT_NMSGQ, 1);
  472                 racct_sub_cred(msqkptr->cred, RACCT_MSGQQUEUED, msqkptr->u.msg_qnum);
  473                 racct_sub_cred(msqkptr->cred, RACCT_MSGQSIZE, msqkptr->u.msg_cbytes);
  474                 crfree(msqkptr->cred);
  475                 msqkptr->cred = NULL;
  476 
  477                 /* Free the message headers */
  478                 msghdr = msqkptr->u.msg_first;
  479                 while (msghdr != NULL) {
  480                         struct msg *msghdr_tmp;
  481 
  482                         /* Free the segments of each message */
  483                         msqkptr->u.msg_cbytes -= msghdr->msg_ts;
  484                         msqkptr->u.msg_qnum--;
  485                         msghdr_tmp = msghdr;
  486                         msghdr = msghdr->msg_next;
  487                         msg_freehdr(msghdr_tmp);
  488                 }
  489 
  490                 if (msqkptr->u.msg_cbytes != 0)
  491                         panic("msg_cbytes is screwed up");
  492                 if (msqkptr->u.msg_qnum != 0)
  493                         panic("msg_qnum is screwed up");
  494 
  495                 msqkptr->u.msg_qbytes = 0;      /* Mark it as free */
  496 
  497 #ifdef MAC
  498                 mac_sysvmsq_cleanup(msqkptr);
  499 #endif
  500 
  501                 wakeup(msqkptr);
  502         }
  503 
  504                 break;
  505 
  506         case IPC_SET:
  507                 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_M)))
  508                         goto done2;
  509                 if (msqbuf->msg_qbytes > msqkptr->u.msg_qbytes) {
  510                         error = priv_check(td, PRIV_IPC_MSGSIZE);
  511                         if (error)
  512                                 goto done2;
  513                 }
  514                 if (msqbuf->msg_qbytes > msginfo.msgmnb) {
  515                         DPRINTF(("can't increase msg_qbytes beyond %d"
  516                             "(truncating)\n", msginfo.msgmnb));
  517                         msqbuf->msg_qbytes = msginfo.msgmnb;    /* silently restrict qbytes to system limit */
  518                 }
  519                 if (msqbuf->msg_qbytes == 0) {
  520                         DPRINTF(("can't reduce msg_qbytes to 0\n"));
  521                         error = EINVAL;         /* non-standard errno! */
  522                         goto done2;
  523                 }
  524                 msqkptr->u.msg_perm.uid = msqbuf->msg_perm.uid; /* change the owner */
  525                 msqkptr->u.msg_perm.gid = msqbuf->msg_perm.gid; /* change the owner */
  526                 msqkptr->u.msg_perm.mode = (msqkptr->u.msg_perm.mode & ~0777) |
  527                     (msqbuf->msg_perm.mode & 0777);
  528                 msqkptr->u.msg_qbytes = msqbuf->msg_qbytes;
  529                 msqkptr->u.msg_ctime = time_second;
  530                 break;
  531 
  532         case IPC_STAT:
  533                 if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
  534                         DPRINTF(("requester doesn't have read access\n"));
  535                         goto done2;
  536                 }
  537                 *msqbuf = msqkptr->u;
  538                 break;
  539 
  540         default:
  541                 DPRINTF(("invalid command %d\n", cmd));
  542                 error = EINVAL;
  543                 goto done2;
  544         }
  545 
  546         if (error == 0)
  547                 td->td_retval[0] = rval;
  548 done2:
  549         mtx_unlock(&msq_mtx);
  550         return (error);
  551 }
  552 
  553 #ifndef _SYS_SYSPROTO_H_
  554 struct msgget_args {
  555         key_t   key;
  556         int     msgflg;
  557 };
  558 #endif
  559 
  560 int
  561 sys_msgget(td, uap)
  562         struct thread *td;
  563         register struct msgget_args *uap;
  564 {
  565         int msqid, error = 0;
  566         int key = uap->key;
  567         int msgflg = uap->msgflg;
  568         struct ucred *cred = td->td_ucred;
  569         register struct msqid_kernel *msqkptr = NULL;
  570 
  571         DPRINTF(("msgget(0x%x, 0%o)\n", key, msgflg));
  572 
  573         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  574                 return (ENOSYS);
  575 
  576         mtx_lock(&msq_mtx);
  577         if (key != IPC_PRIVATE) {
  578                 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
  579                         msqkptr = &msqids[msqid];
  580                         if (msqkptr->u.msg_qbytes != 0 &&
  581                             msqkptr->u.msg_perm.key == key)
  582                                 break;
  583                 }
  584                 if (msqid < msginfo.msgmni) {
  585                         DPRINTF(("found public key\n"));
  586                         if ((msgflg & IPC_CREAT) && (msgflg & IPC_EXCL)) {
  587                                 DPRINTF(("not exclusive\n"));
  588                                 error = EEXIST;
  589                                 goto done2;
  590                         }
  591                         if ((error = ipcperm(td, &msqkptr->u.msg_perm,
  592                             msgflg & 0700))) {
  593                                 DPRINTF(("requester doesn't have 0%o access\n",
  594                                     msgflg & 0700));
  595                                 goto done2;
  596                         }
  597 #ifdef MAC
  598                         error = mac_sysvmsq_check_msqget(cred, msqkptr);
  599                         if (error != 0)
  600                                 goto done2;
  601 #endif
  602                         goto found;
  603                 }
  604         }
  605 
  606         DPRINTF(("need to allocate the msqid_ds\n"));
  607         if (key == IPC_PRIVATE || (msgflg & IPC_CREAT)) {
  608                 for (msqid = 0; msqid < msginfo.msgmni; msqid++) {
  609                         /*
  610                          * Look for an unallocated and unlocked msqid_ds.
  611                          * msqid_ds's can be locked by msgsnd or msgrcv while
  612                          * they are copying the message in/out.  We can't
  613                          * re-use the entry until they release it.
  614                          */
  615                         msqkptr = &msqids[msqid];
  616                         if (msqkptr->u.msg_qbytes == 0 &&
  617                             (msqkptr->u.msg_perm.mode & MSG_LOCKED) == 0)
  618                                 break;
  619                 }
  620                 if (msqid == msginfo.msgmni) {
  621                         DPRINTF(("no more msqid_ds's available\n"));
  622                         error = ENOSPC;
  623                         goto done2;
  624                 }
  625 #ifdef RACCT
  626                 PROC_LOCK(td->td_proc);
  627                 error = racct_add(td->td_proc, RACCT_NMSGQ, 1);
  628                 PROC_UNLOCK(td->td_proc);
  629                 if (error != 0) {
  630                         error = ENOSPC;
  631                         goto done2;
  632                 }
  633 #endif
  634                 DPRINTF(("msqid %d is available\n", msqid));
  635                 msqkptr->u.msg_perm.key = key;
  636                 msqkptr->u.msg_perm.cuid = cred->cr_uid;
  637                 msqkptr->u.msg_perm.uid = cred->cr_uid;
  638                 msqkptr->u.msg_perm.cgid = cred->cr_gid;
  639                 msqkptr->u.msg_perm.gid = cred->cr_gid;
  640                 msqkptr->u.msg_perm.mode = (msgflg & 0777);
  641                 msqkptr->cred = crhold(cred);
  642                 /* Make sure that the returned msqid is unique */
  643                 msqkptr->u.msg_perm.seq = (msqkptr->u.msg_perm.seq + 1) & 0x7fff;
  644                 msqkptr->u.msg_first = NULL;
  645                 msqkptr->u.msg_last = NULL;
  646                 msqkptr->u.msg_cbytes = 0;
  647                 msqkptr->u.msg_qnum = 0;
  648                 msqkptr->u.msg_qbytes = msginfo.msgmnb;
  649                 msqkptr->u.msg_lspid = 0;
  650                 msqkptr->u.msg_lrpid = 0;
  651                 msqkptr->u.msg_stime = 0;
  652                 msqkptr->u.msg_rtime = 0;
  653                 msqkptr->u.msg_ctime = time_second;
  654 #ifdef MAC
  655                 mac_sysvmsq_create(cred, msqkptr);
  656 #endif
  657         } else {
  658                 DPRINTF(("didn't find it and wasn't asked to create it\n"));
  659                 error = ENOENT;
  660                 goto done2;
  661         }
  662 
  663 found:
  664         /* Construct the unique msqid */
  665         td->td_retval[0] = IXSEQ_TO_IPCID(msqid, msqkptr->u.msg_perm);
  666 done2:
  667         mtx_unlock(&msq_mtx);
  668         return (error);
  669 }
  670 
  671 #ifndef _SYS_SYSPROTO_H_
  672 struct msgsnd_args {
  673         int     msqid;
  674         const void      *msgp;
  675         size_t  msgsz;
  676         int     msgflg;
  677 };
  678 #endif
  679 int
  680 kern_msgsnd(td, msqid, msgp, msgsz, msgflg, mtype)
  681         struct thread *td;
  682         int msqid;
  683         const void *msgp;       /* XXX msgp is actually mtext. */
  684         size_t msgsz;
  685         int msgflg;
  686         long mtype;
  687 {
  688         int msqix, segs_needed, error = 0;
  689         register struct msqid_kernel *msqkptr;
  690         register struct msg *msghdr;
  691         short next;
  692 #ifdef RACCT
  693         size_t saved_msgsz;
  694 #endif
  695 
  696         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
  697                 return (ENOSYS);
  698 
  699         mtx_lock(&msq_mtx);
  700         msqix = IPCID_TO_IX(msqid);
  701 
  702         if (msqix < 0 || msqix >= msginfo.msgmni) {
  703                 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
  704                     msginfo.msgmni));
  705                 error = EINVAL;
  706                 goto done2;
  707         }
  708 
  709         msqkptr = &msqids[msqix];
  710         if (msqkptr->u.msg_qbytes == 0) {
  711                 DPRINTF(("no such message queue id\n"));
  712                 error = EINVAL;
  713                 goto done2;
  714         }
  715         if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
  716                 DPRINTF(("wrong sequence number\n"));
  717                 error = EINVAL;
  718                 goto done2;
  719         }
  720 
  721         if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_W))) {
  722                 DPRINTF(("requester doesn't have write access\n"));
  723                 goto done2;
  724         }
  725 
  726 #ifdef MAC
  727         error = mac_sysvmsq_check_msqsnd(td->td_ucred, msqkptr);
  728         if (error != 0)
  729                 goto done2;
  730 #endif
  731 
  732 #ifdef RACCT
  733         PROC_LOCK(td->td_proc);
  734         if (racct_add(td->td_proc, RACCT_MSGQQUEUED, 1)) {
  735                 PROC_UNLOCK(td->td_proc);
  736                 error = EAGAIN;
  737                 goto done2;
  738         }
  739         saved_msgsz = msgsz;
  740         if (racct_add(td->td_proc, RACCT_MSGQSIZE, msgsz)) {
  741                 racct_sub(td->td_proc, RACCT_MSGQQUEUED, 1);
  742                 PROC_UNLOCK(td->td_proc);
  743                 error = EAGAIN;
  744                 goto done2;
  745         }
  746         PROC_UNLOCK(td->td_proc);
  747 #endif
  748 
  749         segs_needed = (msgsz + msginfo.msgssz - 1) / msginfo.msgssz;
  750         DPRINTF(("msgsz=%zu, msgssz=%d, segs_needed=%d\n", msgsz,
  751             msginfo.msgssz, segs_needed));
  752         for (;;) {
  753                 int need_more_resources = 0;
  754 
  755                 /*
  756                  * check msgsz
  757                  * (inside this loop in case msg_qbytes changes while we sleep)
  758                  */
  759 
  760                 if (msgsz > msqkptr->u.msg_qbytes) {
  761                         DPRINTF(("msgsz > msqkptr->u.msg_qbytes\n"));
  762                         error = EINVAL;
  763                         goto done3;
  764                 }
  765 
  766                 if (msqkptr->u.msg_perm.mode & MSG_LOCKED) {
  767                         DPRINTF(("msqid is locked\n"));
  768                         need_more_resources = 1;
  769                 }
  770                 if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes) {
  771                         DPRINTF(("msgsz + msg_cbytes > msg_qbytes\n"));
  772                         need_more_resources = 1;
  773                 }
  774                 if (segs_needed > nfree_msgmaps) {
  775                         DPRINTF(("segs_needed > nfree_msgmaps\n"));
  776                         need_more_resources = 1;
  777                 }
  778                 if (free_msghdrs == NULL) {
  779                         DPRINTF(("no more msghdrs\n"));
  780                         need_more_resources = 1;
  781                 }
  782 
  783                 if (need_more_resources) {
  784                         int we_own_it;
  785 
  786                         if ((msgflg & IPC_NOWAIT) != 0) {
  787                                 DPRINTF(("need more resources but caller "
  788                                     "doesn't want to wait\n"));
  789                                 error = EAGAIN;
  790                                 goto done3;
  791                         }
  792 
  793                         if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0) {
  794                                 DPRINTF(("we don't own the msqid_ds\n"));
  795                                 we_own_it = 0;
  796                         } else {
  797                                 /* Force later arrivals to wait for our
  798                                    request */
  799                                 DPRINTF(("we own the msqid_ds\n"));
  800                                 msqkptr->u.msg_perm.mode |= MSG_LOCKED;
  801                                 we_own_it = 1;
  802                         }
  803                         DPRINTF(("msgsnd:  goodnight\n"));
  804                         error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
  805                             "msgsnd", hz);
  806                         DPRINTF(("msgsnd:  good morning, error=%d\n", error));
  807                         if (we_own_it)
  808                                 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
  809                         if (error == EWOULDBLOCK) {
  810                                 DPRINTF(("msgsnd:  timed out\n"));
  811                                 continue;
  812                         }
  813                         if (error != 0) {
  814                                 DPRINTF(("msgsnd:  interrupted system call\n"));
  815                                 error = EINTR;
  816                                 goto done3;
  817                         }
  818 
  819                         /*
  820                          * Make sure that the msq queue still exists
  821                          */
  822 
  823                         if (msqkptr->u.msg_qbytes == 0) {
  824                                 DPRINTF(("msqid deleted\n"));
  825                                 error = EIDRM;
  826                                 goto done3;
  827                         }
  828 
  829                 } else {
  830                         DPRINTF(("got all the resources that we need\n"));
  831                         break;
  832                 }
  833         }
  834 
  835         /*
  836          * We have the resources that we need.
  837          * Make sure!
  838          */
  839 
  840         if (msqkptr->u.msg_perm.mode & MSG_LOCKED)
  841                 panic("msg_perm.mode & MSG_LOCKED");
  842         if (segs_needed > nfree_msgmaps)
  843                 panic("segs_needed > nfree_msgmaps");
  844         if (msgsz + msqkptr->u.msg_cbytes > msqkptr->u.msg_qbytes)
  845                 panic("msgsz + msg_cbytes > msg_qbytes");
  846         if (free_msghdrs == NULL)
  847                 panic("no more msghdrs");
  848 
  849         /*
  850          * Re-lock the msqid_ds in case we page-fault when copying in the
  851          * message
  852          */
  853 
  854         if ((msqkptr->u.msg_perm.mode & MSG_LOCKED) != 0)
  855                 panic("msqid_ds is already locked");
  856         msqkptr->u.msg_perm.mode |= MSG_LOCKED;
  857 
  858         /*
  859          * Allocate a message header
  860          */
  861 
  862         msghdr = free_msghdrs;
  863         free_msghdrs = msghdr->msg_next;
  864         msghdr->msg_spot = -1;
  865         msghdr->msg_ts = msgsz;
  866         msghdr->msg_type = mtype;
  867 #ifdef MAC
  868         /*
  869          * XXXMAC: Should the mac_sysvmsq_check_msgmsq check follow here
  870          * immediately?  Or, should it be checked just before the msg is
  871          * enqueued in the msgq (as it is done now)?
  872          */
  873         mac_sysvmsg_create(td->td_ucred, msqkptr, msghdr);
  874 #endif
  875 
  876         /*
  877          * Allocate space for the message
  878          */
  879 
  880         while (segs_needed > 0) {
  881                 if (nfree_msgmaps <= 0)
  882                         panic("not enough msgmaps");
  883                 if (free_msgmaps == -1)
  884                         panic("nil free_msgmaps");
  885                 next = free_msgmaps;
  886                 if (next <= -1)
  887                         panic("next too low #1");
  888                 if (next >= msginfo.msgseg)
  889                         panic("next out of range #1");
  890                 DPRINTF(("allocating segment %d to message\n", next));
  891                 free_msgmaps = msgmaps[next].next;
  892                 nfree_msgmaps--;
  893                 msgmaps[next].next = msghdr->msg_spot;
  894                 msghdr->msg_spot = next;
  895                 segs_needed--;
  896         }
  897 
  898         /*
  899          * Validate the message type
  900          */
  901 
  902         if (msghdr->msg_type < 1) {
  903                 msg_freehdr(msghdr);
  904                 msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
  905                 wakeup(msqkptr);
  906                 DPRINTF(("mtype (%ld) < 1\n", msghdr->msg_type));
  907                 error = EINVAL;
  908                 goto done3;
  909         }
  910 
  911         /*
  912          * Copy in the message body
  913          */
  914 
  915         next = msghdr->msg_spot;
  916         while (msgsz > 0) {
  917                 size_t tlen;
  918                 if (msgsz > msginfo.msgssz)
  919                         tlen = msginfo.msgssz;
  920                 else
  921                         tlen = msgsz;
  922                 if (next <= -1)
  923                         panic("next too low #2");
  924                 if (next >= msginfo.msgseg)
  925                         panic("next out of range #2");
  926                 mtx_unlock(&msq_mtx);
  927                 if ((error = copyin(msgp, &msgpool[next * msginfo.msgssz],
  928                     tlen)) != 0) {
  929                         mtx_lock(&msq_mtx);
  930                         DPRINTF(("error %d copying in message segment\n",
  931                             error));
  932                         msg_freehdr(msghdr);
  933                         msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
  934                         wakeup(msqkptr);
  935                         goto done3;
  936                 }
  937                 mtx_lock(&msq_mtx);
  938                 msgsz -= tlen;
  939                 msgp = (const char *)msgp + tlen;
  940                 next = msgmaps[next].next;
  941         }
  942         if (next != -1)
  943                 panic("didn't use all the msg segments");
  944 
  945         /*
  946          * We've got the message.  Unlock the msqid_ds.
  947          */
  948 
  949         msqkptr->u.msg_perm.mode &= ~MSG_LOCKED;
  950 
  951         /*
  952          * Make sure that the msqid_ds is still allocated.
  953          */
  954 
  955         if (msqkptr->u.msg_qbytes == 0) {
  956                 msg_freehdr(msghdr);
  957                 wakeup(msqkptr);
  958                 error = EIDRM;
  959                 goto done3;
  960         }
  961 
  962 #ifdef MAC
  963         /*
  964          * Note: Since the task/thread allocates the msghdr and usually
  965          * primes it with its own MAC label, for a majority of policies, it
  966          * won't be necessary to check whether the msghdr has access
  967          * permissions to the msgq.  The mac_sysvmsq_check_msqsnd check would
  968          * suffice in that case.  However, this hook may be required where
  969          * individual policies derive a non-identical label for the msghdr
  970          * from the current thread label and may want to check the msghdr
  971          * enqueue permissions, along with read/write permissions to the
  972          * msgq.
  973          */
  974         error = mac_sysvmsq_check_msgmsq(td->td_ucred, msghdr, msqkptr);
  975         if (error != 0) {
  976                 msg_freehdr(msghdr);
  977                 wakeup(msqkptr);
  978                 goto done3;
  979         }
  980 #endif
  981 
  982         /*
  983          * Put the message into the queue
  984          */
  985         if (msqkptr->u.msg_first == NULL) {
  986                 msqkptr->u.msg_first = msghdr;
  987                 msqkptr->u.msg_last = msghdr;
  988         } else {
  989                 msqkptr->u.msg_last->msg_next = msghdr;
  990                 msqkptr->u.msg_last = msghdr;
  991         }
  992         msqkptr->u.msg_last->msg_next = NULL;
  993 
  994         msqkptr->u.msg_cbytes += msghdr->msg_ts;
  995         msqkptr->u.msg_qnum++;
  996         msqkptr->u.msg_lspid = td->td_proc->p_pid;
  997         msqkptr->u.msg_stime = time_second;
  998 
  999         wakeup(msqkptr);
 1000         td->td_retval[0] = 0;
 1001 done3:
 1002 #ifdef RACCT
 1003         if (error != 0) {
 1004                 PROC_LOCK(td->td_proc);
 1005                 racct_sub(td->td_proc, RACCT_MSGQQUEUED, 1);
 1006                 racct_sub(td->td_proc, RACCT_MSGQSIZE, saved_msgsz);
 1007                 PROC_UNLOCK(td->td_proc);
 1008         }
 1009 #endif
 1010 done2:
 1011         mtx_unlock(&msq_mtx);
 1012         return (error);
 1013 }
 1014 
 1015 int
 1016 sys_msgsnd(td, uap)
 1017         struct thread *td;
 1018         register struct msgsnd_args *uap;
 1019 {
 1020         int error;
 1021         long mtype;
 1022 
 1023         DPRINTF(("call to msgsnd(%d, %p, %zu, %d)\n", uap->msqid, uap->msgp,
 1024             uap->msgsz, uap->msgflg));
 1025 
 1026         if ((error = copyin(uap->msgp, &mtype, sizeof(mtype))) != 0) {
 1027                 DPRINTF(("error %d copying the message type\n", error));
 1028                 return (error);
 1029         }
 1030         return (kern_msgsnd(td, uap->msqid,
 1031             (const char *)uap->msgp + sizeof(mtype),
 1032             uap->msgsz, uap->msgflg, mtype));
 1033 }
 1034 
 1035 #ifndef _SYS_SYSPROTO_H_
 1036 struct msgrcv_args {
 1037         int     msqid;
 1038         void    *msgp;
 1039         size_t  msgsz;
 1040         long    msgtyp;
 1041         int     msgflg;
 1042 };
 1043 #endif
 1044 int
 1045 kern_msgrcv(td, msqid, msgp, msgsz, msgtyp, msgflg, mtype)
 1046         struct thread *td;
 1047         int msqid;
 1048         void *msgp;     /* XXX msgp is actually mtext. */
 1049         size_t msgsz;
 1050         long msgtyp;
 1051         int msgflg;
 1052         long *mtype;
 1053 {
 1054         size_t len;
 1055         register struct msqid_kernel *msqkptr;
 1056         register struct msg *msghdr;
 1057         int msqix, error = 0;
 1058         short next;
 1059 
 1060         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
 1061                 return (ENOSYS);
 1062 
 1063         msqix = IPCID_TO_IX(msqid);
 1064 
 1065         if (msqix < 0 || msqix >= msginfo.msgmni) {
 1066                 DPRINTF(("msqid (%d) out of range (0<=msqid<%d)\n", msqix,
 1067                     msginfo.msgmni));
 1068                 return (EINVAL);
 1069         }
 1070 
 1071         msqkptr = &msqids[msqix];
 1072         mtx_lock(&msq_mtx);
 1073         if (msqkptr->u.msg_qbytes == 0) {
 1074                 DPRINTF(("no such message queue id\n"));
 1075                 error = EINVAL;
 1076                 goto done2;
 1077         }
 1078         if (msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
 1079                 DPRINTF(("wrong sequence number\n"));
 1080                 error = EINVAL;
 1081                 goto done2;
 1082         }
 1083 
 1084         if ((error = ipcperm(td, &msqkptr->u.msg_perm, IPC_R))) {
 1085                 DPRINTF(("requester doesn't have read access\n"));
 1086                 goto done2;
 1087         }
 1088 
 1089 #ifdef MAC
 1090         error = mac_sysvmsq_check_msqrcv(td->td_ucred, msqkptr);
 1091         if (error != 0)
 1092                 goto done2;
 1093 #endif
 1094 
 1095         msghdr = NULL;
 1096         while (msghdr == NULL) {
 1097                 if (msgtyp == 0) {
 1098                         msghdr = msqkptr->u.msg_first;
 1099                         if (msghdr != NULL) {
 1100                                 if (msgsz < msghdr->msg_ts &&
 1101                                     (msgflg & MSG_NOERROR) == 0) {
 1102                                         DPRINTF(("first message on the queue "
 1103                                             "is too big (want %zu, got %d)\n",
 1104                                             msgsz, msghdr->msg_ts));
 1105                                         error = E2BIG;
 1106                                         goto done2;
 1107                                 }
 1108 #ifdef MAC
 1109                                 error = mac_sysvmsq_check_msgrcv(td->td_ucred,
 1110                                     msghdr);
 1111                                 if (error != 0)
 1112                                         goto done2;
 1113 #endif
 1114                                 if (msqkptr->u.msg_first == msqkptr->u.msg_last) {
 1115                                         msqkptr->u.msg_first = NULL;
 1116                                         msqkptr->u.msg_last = NULL;
 1117                                 } else {
 1118                                         msqkptr->u.msg_first = msghdr->msg_next;
 1119                                         if (msqkptr->u.msg_first == NULL)
 1120                                                 panic("msg_first/last screwed up #1");
 1121                                 }
 1122                         }
 1123                 } else {
 1124                         struct msg *previous;
 1125                         struct msg **prev;
 1126 
 1127                         previous = NULL;
 1128                         prev = &(msqkptr->u.msg_first);
 1129                         while ((msghdr = *prev) != NULL) {
 1130                                 /*
 1131                                  * Is this message's type an exact match or is
 1132                                  * this message's type less than or equal to
 1133                                  * the absolute value of a negative msgtyp?
 1134                                  * Note that the second half of this test can
 1135                                  * NEVER be true if msgtyp is positive since
 1136                                  * msg_type is always positive!
 1137                                  */
 1138 
 1139                                 if (msgtyp == msghdr->msg_type ||
 1140                                     msghdr->msg_type <= -msgtyp) {
 1141                                         DPRINTF(("found message type %ld, "
 1142                                             "requested %ld\n",
 1143                                             msghdr->msg_type, msgtyp));
 1144                                         if (msgsz < msghdr->msg_ts &&
 1145                                             (msgflg & MSG_NOERROR) == 0) {
 1146                                                 DPRINTF(("requested message "
 1147                                                     "on the queue is too big "
 1148                                                     "(want %zu, got %hu)\n",
 1149                                                     msgsz, msghdr->msg_ts));
 1150                                                 error = E2BIG;
 1151                                                 goto done2;
 1152                                         }
 1153 #ifdef MAC
 1154                                         error = mac_sysvmsq_check_msgrcv(
 1155                                             td->td_ucred, msghdr);
 1156                                         if (error != 0)
 1157                                                 goto done2;
 1158 #endif
 1159                                         *prev = msghdr->msg_next;
 1160                                         if (msghdr == msqkptr->u.msg_last) {
 1161                                                 if (previous == NULL) {
 1162                                                         if (prev !=
 1163                                                             &msqkptr->u.msg_first)
 1164                                                                 panic("msg_first/last screwed up #2");
 1165                                                         msqkptr->u.msg_first =
 1166                                                             NULL;
 1167                                                         msqkptr->u.msg_last =
 1168                                                             NULL;
 1169                                                 } else {
 1170                                                         if (prev ==
 1171                                                             &msqkptr->u.msg_first)
 1172                                                                 panic("msg_first/last screwed up #3");
 1173                                                         msqkptr->u.msg_last =
 1174                                                             previous;
 1175                                                 }
 1176                                         }
 1177                                         break;
 1178                                 }
 1179                                 previous = msghdr;
 1180                                 prev = &(msghdr->msg_next);
 1181                         }
 1182                 }
 1183 
 1184                 /*
 1185                  * We've either extracted the msghdr for the appropriate
 1186                  * message or there isn't one.
 1187                  * If there is one then bail out of this loop.
 1188                  */
 1189 
 1190                 if (msghdr != NULL)
 1191                         break;
 1192 
 1193                 /*
 1194                  * Hmph!  No message found.  Does the user want to wait?
 1195                  */
 1196 
 1197                 if ((msgflg & IPC_NOWAIT) != 0) {
 1198                         DPRINTF(("no appropriate message found (msgtyp=%ld)\n",
 1199                             msgtyp));
 1200                         /* The SVID says to return ENOMSG. */
 1201                         error = ENOMSG;
 1202                         goto done2;
 1203                 }
 1204 
 1205                 /*
 1206                  * Wait for something to happen
 1207                  */
 1208 
 1209                 DPRINTF(("msgrcv:  goodnight\n"));
 1210                 error = msleep(msqkptr, &msq_mtx, (PZERO - 4) | PCATCH,
 1211                     "msgrcv", 0);
 1212                 DPRINTF(("msgrcv:  good morning (error=%d)\n", error));
 1213 
 1214                 if (error != 0) {
 1215                         DPRINTF(("msgrcv:  interrupted system call\n"));
 1216                         error = EINTR;
 1217                         goto done2;
 1218                 }
 1219 
 1220                 /*
 1221                  * Make sure that the msq queue still exists
 1222                  */
 1223 
 1224                 if (msqkptr->u.msg_qbytes == 0 ||
 1225                     msqkptr->u.msg_perm.seq != IPCID_TO_SEQ(msqid)) {
 1226                         DPRINTF(("msqid deleted\n"));
 1227                         error = EIDRM;
 1228                         goto done2;
 1229                 }
 1230         }
 1231 
 1232         /*
 1233          * Return the message to the user.
 1234          *
 1235          * First, do the bookkeeping (before we risk being interrupted).
 1236          */
 1237 
 1238         msqkptr->u.msg_cbytes -= msghdr->msg_ts;
 1239         msqkptr->u.msg_qnum--;
 1240         msqkptr->u.msg_lrpid = td->td_proc->p_pid;
 1241         msqkptr->u.msg_rtime = time_second;
 1242 
 1243         racct_sub_cred(msqkptr->cred, RACCT_MSGQQUEUED, 1);
 1244         racct_sub_cred(msqkptr->cred, RACCT_MSGQSIZE, msghdr->msg_ts);
 1245 
 1246         /*
 1247          * Make msgsz the actual amount that we'll be returning.
 1248          * Note that this effectively truncates the message if it is too long
 1249          * (since msgsz is never increased).
 1250          */
 1251 
 1252         DPRINTF(("found a message, msgsz=%zu, msg_ts=%hu\n", msgsz,
 1253             msghdr->msg_ts));
 1254         if (msgsz > msghdr->msg_ts)
 1255                 msgsz = msghdr->msg_ts;
 1256         *mtype = msghdr->msg_type;
 1257 
 1258         /*
 1259          * Return the segments to the user
 1260          */
 1261 
 1262         next = msghdr->msg_spot;
 1263         for (len = 0; len < msgsz; len += msginfo.msgssz) {
 1264                 size_t tlen;
 1265 
 1266                 if (msgsz - len > msginfo.msgssz)
 1267                         tlen = msginfo.msgssz;
 1268                 else
 1269                         tlen = msgsz - len;
 1270                 if (next <= -1)
 1271                         panic("next too low #3");
 1272                 if (next >= msginfo.msgseg)
 1273                         panic("next out of range #3");
 1274                 mtx_unlock(&msq_mtx);
 1275                 error = copyout(&msgpool[next * msginfo.msgssz], msgp, tlen);
 1276                 mtx_lock(&msq_mtx);
 1277                 if (error != 0) {
 1278                         DPRINTF(("error (%d) copying out message segment\n",
 1279                             error));
 1280                         msg_freehdr(msghdr);
 1281                         wakeup(msqkptr);
 1282                         goto done2;
 1283                 }
 1284                 msgp = (char *)msgp + tlen;
 1285                 next = msgmaps[next].next;
 1286         }
 1287 
 1288         /*
 1289          * Done, return the actual number of bytes copied out.
 1290          */
 1291 
 1292         msg_freehdr(msghdr);
 1293         wakeup(msqkptr);
 1294         td->td_retval[0] = msgsz;
 1295 done2:
 1296         mtx_unlock(&msq_mtx);
 1297         return (error);
 1298 }
 1299 
 1300 int
 1301 sys_msgrcv(td, uap)
 1302         struct thread *td;
 1303         register struct msgrcv_args *uap;
 1304 {
 1305         int error;
 1306         long mtype;
 1307 
 1308         DPRINTF(("call to msgrcv(%d, %p, %zu, %ld, %d)\n", uap->msqid,
 1309             uap->msgp, uap->msgsz, uap->msgtyp, uap->msgflg));
 1310 
 1311         if ((error = kern_msgrcv(td, uap->msqid,
 1312             (char *)uap->msgp + sizeof(mtype), uap->msgsz,
 1313             uap->msgtyp, uap->msgflg, &mtype)) != 0)
 1314                 return (error);
 1315         if ((error = copyout(&mtype, uap->msgp, sizeof(mtype))) != 0)
 1316                 DPRINTF(("error %d copying the message type\n", error));
 1317         return (error);
 1318 }
 1319 
 1320 static int
 1321 sysctl_msqids(SYSCTL_HANDLER_ARGS)
 1322 {
 1323 
 1324         return (SYSCTL_OUT(req, msqids,
 1325             sizeof(struct msqid_kernel) * msginfo.msgmni));
 1326 }
 1327 
 1328 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmax, CTLFLAG_RD, &msginfo.msgmax, 0,
 1329     "Maximum message size");
 1330 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmni, CTLFLAG_RDTUN, &msginfo.msgmni, 0,
 1331     "Number of message queue identifiers");
 1332 SYSCTL_INT(_kern_ipc, OID_AUTO, msgmnb, CTLFLAG_RDTUN, &msginfo.msgmnb, 0,
 1333     "Maximum number of bytes in a queue");
 1334 SYSCTL_INT(_kern_ipc, OID_AUTO, msgtql, CTLFLAG_RDTUN, &msginfo.msgtql, 0,
 1335     "Maximum number of messages in the system");
 1336 SYSCTL_INT(_kern_ipc, OID_AUTO, msgssz, CTLFLAG_RDTUN, &msginfo.msgssz, 0,
 1337     "Size of a message segment");
 1338 SYSCTL_INT(_kern_ipc, OID_AUTO, msgseg, CTLFLAG_RDTUN, &msginfo.msgseg, 0,
 1339     "Number of message segments");
 1340 SYSCTL_PROC(_kern_ipc, OID_AUTO, msqids, CTLTYPE_OPAQUE | CTLFLAG_RD,
 1341     NULL, 0, sysctl_msqids, "", "Message queue IDs");
 1342 
 1343 #ifdef COMPAT_FREEBSD32
 1344 int
 1345 freebsd32_msgsys(struct thread *td, struct freebsd32_msgsys_args *uap)
 1346 {
 1347 
 1348 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
 1349     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
 1350         switch (uap->which) {
 1351         case 0:
 1352                 return (freebsd7_freebsd32_msgctl(td,
 1353                     (struct freebsd7_freebsd32_msgctl_args *)&uap->a2));
 1354         case 2:
 1355                 return (freebsd32_msgsnd(td,
 1356                     (struct freebsd32_msgsnd_args *)&uap->a2));
 1357         case 3:
 1358                 return (freebsd32_msgrcv(td,
 1359                     (struct freebsd32_msgrcv_args *)&uap->a2));
 1360         default:
 1361                 return (sys_msgsys(td, (struct msgsys_args *)uap));
 1362         }
 1363 #else
 1364         return (nosys(td, NULL));
 1365 #endif
 1366 }
 1367 
 1368 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
 1369     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
 1370 int
 1371 freebsd7_freebsd32_msgctl(struct thread *td,
 1372     struct freebsd7_freebsd32_msgctl_args *uap)
 1373 {
 1374         struct msqid_ds msqbuf;
 1375         struct msqid_ds32_old msqbuf32;
 1376         int error;
 1377 
 1378         if (uap->cmd == IPC_SET) {
 1379                 error = copyin(uap->buf, &msqbuf32, sizeof(msqbuf32));
 1380                 if (error)
 1381                         return (error);
 1382                 freebsd32_ipcperm_old_in(&msqbuf32.msg_perm, &msqbuf.msg_perm);
 1383                 PTRIN_CP(msqbuf32, msqbuf, msg_first);
 1384                 PTRIN_CP(msqbuf32, msqbuf, msg_last);
 1385                 CP(msqbuf32, msqbuf, msg_cbytes);
 1386                 CP(msqbuf32, msqbuf, msg_qnum);
 1387                 CP(msqbuf32, msqbuf, msg_qbytes);
 1388                 CP(msqbuf32, msqbuf, msg_lspid);
 1389                 CP(msqbuf32, msqbuf, msg_lrpid);
 1390                 CP(msqbuf32, msqbuf, msg_stime);
 1391                 CP(msqbuf32, msqbuf, msg_rtime);
 1392                 CP(msqbuf32, msqbuf, msg_ctime);
 1393         }
 1394         error = kern_msgctl(td, uap->msqid, uap->cmd, &msqbuf);
 1395         if (error)
 1396                 return (error);
 1397         if (uap->cmd == IPC_STAT) {
 1398                 bzero(&msqbuf32, sizeof(msqbuf32));
 1399                 freebsd32_ipcperm_old_out(&msqbuf.msg_perm, &msqbuf32.msg_perm);
 1400                 PTROUT_CP(msqbuf, msqbuf32, msg_first);
 1401                 PTROUT_CP(msqbuf, msqbuf32, msg_last);
 1402                 CP(msqbuf, msqbuf32, msg_cbytes);
 1403                 CP(msqbuf, msqbuf32, msg_qnum);
 1404                 CP(msqbuf, msqbuf32, msg_qbytes);
 1405                 CP(msqbuf, msqbuf32, msg_lspid);
 1406                 CP(msqbuf, msqbuf32, msg_lrpid);
 1407                 CP(msqbuf, msqbuf32, msg_stime);
 1408                 CP(msqbuf, msqbuf32, msg_rtime);
 1409                 CP(msqbuf, msqbuf32, msg_ctime);
 1410                 error = copyout(&msqbuf32, uap->buf, sizeof(struct msqid_ds32));
 1411         }
 1412         return (error);
 1413 }
 1414 #endif
 1415 
 1416 int
 1417 freebsd32_msgctl(struct thread *td, struct freebsd32_msgctl_args *uap)
 1418 {
 1419         struct msqid_ds msqbuf;
 1420         struct msqid_ds32 msqbuf32;
 1421         int error;
 1422 
 1423         if (uap->cmd == IPC_SET) {
 1424                 error = copyin(uap->buf, &msqbuf32, sizeof(msqbuf32));
 1425                 if (error)
 1426                         return (error);
 1427                 freebsd32_ipcperm_in(&msqbuf32.msg_perm, &msqbuf.msg_perm);
 1428                 PTRIN_CP(msqbuf32, msqbuf, msg_first);
 1429                 PTRIN_CP(msqbuf32, msqbuf, msg_last);
 1430                 CP(msqbuf32, msqbuf, msg_cbytes);
 1431                 CP(msqbuf32, msqbuf, msg_qnum);
 1432                 CP(msqbuf32, msqbuf, msg_qbytes);
 1433                 CP(msqbuf32, msqbuf, msg_lspid);
 1434                 CP(msqbuf32, msqbuf, msg_lrpid);
 1435                 CP(msqbuf32, msqbuf, msg_stime);
 1436                 CP(msqbuf32, msqbuf, msg_rtime);
 1437                 CP(msqbuf32, msqbuf, msg_ctime);
 1438         }
 1439         error = kern_msgctl(td, uap->msqid, uap->cmd, &msqbuf);
 1440         if (error)
 1441                 return (error);
 1442         if (uap->cmd == IPC_STAT) {
 1443                 freebsd32_ipcperm_out(&msqbuf.msg_perm, &msqbuf32.msg_perm);
 1444                 PTROUT_CP(msqbuf, msqbuf32, msg_first);
 1445                 PTROUT_CP(msqbuf, msqbuf32, msg_last);
 1446                 CP(msqbuf, msqbuf32, msg_cbytes);
 1447                 CP(msqbuf, msqbuf32, msg_qnum);
 1448                 CP(msqbuf, msqbuf32, msg_qbytes);
 1449                 CP(msqbuf, msqbuf32, msg_lspid);
 1450                 CP(msqbuf, msqbuf32, msg_lrpid);
 1451                 CP(msqbuf, msqbuf32, msg_stime);
 1452                 CP(msqbuf, msqbuf32, msg_rtime);
 1453                 CP(msqbuf, msqbuf32, msg_ctime);
 1454                 error = copyout(&msqbuf32, uap->buf, sizeof(struct msqid_ds32));
 1455         }
 1456         return (error);
 1457 }
 1458 
 1459 int
 1460 freebsd32_msgsnd(struct thread *td, struct freebsd32_msgsnd_args *uap)
 1461 {
 1462         const void *msgp;
 1463         long mtype;
 1464         int32_t mtype32;
 1465         int error;
 1466 
 1467         msgp = PTRIN(uap->msgp);
 1468         if ((error = copyin(msgp, &mtype32, sizeof(mtype32))) != 0)
 1469                 return (error);
 1470         mtype = mtype32;
 1471         return (kern_msgsnd(td, uap->msqid,
 1472             (const char *)msgp + sizeof(mtype32),
 1473             uap->msgsz, uap->msgflg, mtype));
 1474 }
 1475 
 1476 int
 1477 freebsd32_msgrcv(struct thread *td, struct freebsd32_msgrcv_args *uap)
 1478 {
 1479         void *msgp;
 1480         long mtype;
 1481         int32_t mtype32;
 1482         int error;
 1483 
 1484         msgp = PTRIN(uap->msgp);
 1485         if ((error = kern_msgrcv(td, uap->msqid,
 1486             (char *)msgp + sizeof(mtype32), uap->msgsz,
 1487             uap->msgtyp, uap->msgflg, &mtype)) != 0)
 1488                 return (error);
 1489         mtype32 = (int32_t)mtype;
 1490         return (copyout(&mtype32, msgp, sizeof(mtype32)));
 1491 }
 1492 #endif
 1493 
 1494 #if defined(COMPAT_FREEBSD4) || defined(COMPAT_FREEBSD5) || \
 1495     defined(COMPAT_FREEBSD6) || defined(COMPAT_FREEBSD7)
 1496 
 1497 /* XXX casting to (sy_call_t *) is bogus, as usual. */
 1498 static sy_call_t *msgcalls[] = {
 1499         (sy_call_t *)freebsd7_msgctl, (sy_call_t *)sys_msgget,
 1500         (sy_call_t *)sys_msgsnd, (sy_call_t *)sys_msgrcv
 1501 };
 1502 
 1503 /*
 1504  * Entry point for all MSG calls.
 1505  */
 1506 int
 1507 sys_msgsys(td, uap)
 1508         struct thread *td;
 1509         /* XXX actually varargs. */
 1510         struct msgsys_args /* {
 1511                 int     which;
 1512                 int     a2;
 1513                 int     a3;
 1514                 int     a4;
 1515                 int     a5;
 1516                 int     a6;
 1517         } */ *uap;
 1518 {
 1519         int error;
 1520 
 1521         if (!prison_allow(td->td_ucred, PR_ALLOW_SYSVIPC))
 1522                 return (ENOSYS);
 1523         if (uap->which < 0 ||
 1524             uap->which >= sizeof(msgcalls)/sizeof(msgcalls[0]))
 1525                 return (EINVAL);
 1526         error = (*msgcalls[uap->which])(td, &uap->a2);
 1527         return (error);
 1528 }
 1529 
 1530 #ifndef CP
 1531 #define CP(src, dst, fld)       do { (dst).fld = (src).fld; } while (0)
 1532 #endif
 1533 
 1534 #ifndef _SYS_SYSPROTO_H_
 1535 struct freebsd7_msgctl_args {
 1536         int     msqid;
 1537         int     cmd;
 1538         struct  msqid_ds_old *buf;
 1539 };
 1540 #endif
 1541 int
 1542 freebsd7_msgctl(td, uap)
 1543         struct thread *td;
 1544         struct freebsd7_msgctl_args *uap;
 1545 {
 1546         struct msqid_ds_old msqold;
 1547         struct msqid_ds msqbuf;
 1548         int error;
 1549 
 1550         DPRINTF(("call to freebsd7_msgctl(%d, %d, %p)\n", uap->msqid, uap->cmd,
 1551             uap->buf));
 1552         if (uap->cmd == IPC_SET) {
 1553                 error = copyin(uap->buf, &msqold, sizeof(msqold));
 1554                 if (error)
 1555                         return (error);
 1556                 ipcperm_old2new(&msqold.msg_perm, &msqbuf.msg_perm);
 1557                 CP(msqold, msqbuf, msg_first);
 1558                 CP(msqold, msqbuf, msg_last);
 1559                 CP(msqold, msqbuf, msg_cbytes);
 1560                 CP(msqold, msqbuf, msg_qnum);
 1561                 CP(msqold, msqbuf, msg_qbytes);
 1562                 CP(msqold, msqbuf, msg_lspid);
 1563                 CP(msqold, msqbuf, msg_lrpid);
 1564                 CP(msqold, msqbuf, msg_stime);
 1565                 CP(msqold, msqbuf, msg_rtime);
 1566                 CP(msqold, msqbuf, msg_ctime);
 1567         }
 1568         error = kern_msgctl(td, uap->msqid, uap->cmd, &msqbuf);
 1569         if (error)
 1570                 return (error);
 1571         if (uap->cmd == IPC_STAT) {
 1572                 bzero(&msqold, sizeof(msqold));
 1573                 ipcperm_new2old(&msqbuf.msg_perm, &msqold.msg_perm);
 1574                 CP(msqbuf, msqold, msg_first);
 1575                 CP(msqbuf, msqold, msg_last);
 1576                 CP(msqbuf, msqold, msg_cbytes);
 1577                 CP(msqbuf, msqold, msg_qnum);
 1578                 CP(msqbuf, msqold, msg_qbytes);
 1579                 CP(msqbuf, msqold, msg_lspid);
 1580                 CP(msqbuf, msqold, msg_lrpid);
 1581                 CP(msqbuf, msqold, msg_stime);
 1582                 CP(msqbuf, msqold, msg_rtime);
 1583                 CP(msqbuf, msqold, msg_ctime);
 1584                 error = copyout(&msqold, uap->buf, sizeof(struct msqid_ds_old));
 1585         }
 1586         return (error);
 1587 }
 1588 
 1589 #undef CP
 1590 
 1591 #endif  /* COMPAT_FREEBSD4 || COMPAT_FREEBSD5 || COMPAT_FREEBSD6 ||
 1592            COMPAT_FREEBSD7 */

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