/* $NetBSD: sys_mqueue.c,v 1.10 2008/04/24 15:35:30 ad Exp $ */ /* * Copyright (c) 2007, 2008 Mindaugas Rasiukevicius * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * 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. */ /* * Implementation of POSIX message queues. * Defined in the Base Definitions volume of IEEE Std 1003.1-2001. * * Locking * Global list of message queues and proc::p_mqueue_cnt counter are protected * by mqlist_mtx lock. Concrete message queue and its members are protected * by mqueue::mq_mtx. * * Lock order: * mqlist_mtx * -> mqueue::mq_mtx */ #include __KERNEL_RCSID(0, "$NetBSD: sys_mqueue.c,v 1.10 2008/04/24 15:35:30 ad Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* System-wide limits. */ static u_int mq_open_max = MQ_OPEN_MAX; static u_int mq_prio_max = MQ_PRIO_MAX; static u_int mq_max_msgsize = 16 * MQ_DEF_MSGSIZE; static u_int mq_def_maxmsg = 32; static kmutex_t mqlist_mtx; static pool_cache_t mqmsg_cache; static LIST_HEAD(, mqueue) mqueue_head = LIST_HEAD_INITIALIZER(mqueue_head); static int mq_poll_fop(file_t *, int); static int mq_close_fop(file_t *); static const struct fileops mqops = { fbadop_read, fbadop_write, fbadop_ioctl, fnullop_fcntl, mq_poll_fop, fbadop_stat, mq_close_fop, fnullop_kqfilter }; /* * Initialize POSIX message queue subsystem. */ void mqueue_sysinit(void) { mqmsg_cache = pool_cache_init(MQ_DEF_MSGSIZE, coherency_unit, 0, 0, "mqmsg_cache", NULL, IPL_NONE, NULL, NULL, NULL); mutex_init(&mqlist_mtx, MUTEX_DEFAULT, IPL_NONE); } /* * Free the message. */ static void mqueue_freemsg(struct mq_msg *msg, const size_t size) { if (size > MQ_DEF_MSGSIZE) kmem_free(msg, size); else pool_cache_put(mqmsg_cache, msg); } /* * Destroy the message queue. */ static void mqueue_destroy(struct mqueue *mq) { struct mq_msg *msg; while ((msg = TAILQ_FIRST(&mq->mq_head)) != NULL) { TAILQ_REMOVE(&mq->mq_head, msg, msg_queue); mqueue_freemsg(msg, sizeof(struct mq_msg) + msg->msg_len); } seldestroy(&mq->mq_rsel); seldestroy(&mq->mq_wsel); cv_destroy(&mq->mq_send_cv); cv_destroy(&mq->mq_recv_cv); mutex_destroy(&mq->mq_mtx); kmem_free(mq, sizeof(struct mqueue)); } /* * Lookup for file name in general list of message queues. * => locks the message queue */ static void * mqueue_lookup(char *name) { struct mqueue *mq; KASSERT(mutex_owned(&mqlist_mtx)); LIST_FOREACH(mq, &mqueue_head, mq_list) { if (strncmp(mq->mq_name, name, MQ_NAMELEN) == 0) { mutex_enter(&mq->mq_mtx); return mq; } } return NULL; } /* * Check access against message queue. */ static inline int mqueue_access(struct lwp *l, struct mqueue *mq, mode_t acc_mode) { KASSERT(mutex_owned(&mq->mq_mtx)); return vaccess(VNON, mq->mq_mode, mq->mq_euid, mq->mq_egid, acc_mode, l->l_cred); } /* * Get the mqueue from the descriptor. * => locks the message queue * => increments the reference on file entry */ static int mqueue_get(struct lwp *l, mqd_t mqd, mode_t acc_mode, file_t **fpr) { file_t *fp; struct mqueue *mq; /* Get the file and descriptor */ fp = fd_getfile((int)mqd); if (fp == NULL) return EBADF; /* Increment the reference of file entry, and lock the mqueue */ mq = fp->f_data; *fpr = fp; mutex_enter(&mq->mq_mtx); /* Check the access mode and permission if needed */ if (acc_mode == VNOVAL) return 0; if ((acc_mode & fp->f_flag) == 0 || mqueue_access(l, mq, acc_mode)) { mutex_exit(&mq->mq_mtx); fd_putfile((int)mqd); return EPERM; } return 0; } /* * Converter from struct timespec to the ticks. * Used by mq_timedreceive(), mq_timedsend(). */ static int abstimeout2timo(const void *uaddr, int *timo) { struct timespec ts; int error; error = copyin(uaddr, &ts, sizeof(struct timespec)); if (error) return error; /* * According to POSIX, validation check is needed only in case of * blocking. Thus, set the invalid value right now, and fail latter. */ error = itimespecfix(&ts); *timo = (error == 0) ? tstohz(&ts) : -1; return 0; } static int mq_poll_fop(file_t *fp, int events) { struct mqueue *mq = fp->f_data; int revents = 0; mutex_enter(&mq->mq_mtx); if (events & (POLLIN | POLLRDNORM)) { /* Ready for receiving, if there are messages in the queue */ if (mq->mq_attrib.mq_curmsgs) revents |= (POLLIN | POLLRDNORM); else selrecord(curlwp, &mq->mq_rsel); } if (events & (POLLOUT | POLLWRNORM)) { /* Ready for sending, if the message queue is not full */ if (mq->mq_attrib.mq_curmsgs < mq->mq_attrib.mq_maxmsg) revents |= (POLLOUT | POLLWRNORM); else selrecord(curlwp, &mq->mq_wsel); } mutex_exit(&mq->mq_mtx); return revents; } static int mq_close_fop(file_t *fp) { struct proc *p = curproc; struct mqueue *mq = fp->f_data; bool destroy; mutex_enter(&mqlist_mtx); mutex_enter(&mq->mq_mtx); /* Decrease the counters */ p->p_mqueue_cnt--; mq->mq_refcnt--; /* Remove notification if registered for this process */ if (mq->mq_notify_proc == p) mq->mq_notify_proc = NULL; /* * If this is the last reference and mqueue is marked for unlink, * remove and later destroy the message queue. */ if (mq->mq_refcnt == 0 && (mq->mq_attrib.mq_flags & MQ_UNLINK)) { LIST_REMOVE(mq, mq_list); destroy = true; } else destroy = false; mutex_exit(&mq->mq_mtx); mutex_exit(&mqlist_mtx); if (destroy) mqueue_destroy(mq); return 0; } /* * General mqueue system calls. */ int sys_mq_open(struct lwp *l, const struct sys_mq_open_args *uap, register_t *retval) { /* { syscallarg(const char *) name; syscallarg(int) oflag; syscallarg(mode_t) mode; syscallarg(struct mq_attr) attr; } */ struct proc *p = l->l_proc; struct mqueue *mq, *mq_new = NULL; file_t *fp; char *name; int mqd, error, oflag; /* Check access mode flags */ oflag = SCARG(uap, oflag); if ((oflag & (O_RDWR | O_RDONLY | O_WRONLY)) == 0) return EINVAL; /* Get the name from the user-space */ name = kmem_zalloc(MQ_NAMELEN, KM_SLEEP); error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL); if (error) { kmem_free(name, MQ_NAMELEN); return error; } if (oflag & O_CREAT) { struct mq_attr attr; /* Check the limit */ if (p->p_mqueue_cnt == mq_open_max) { kmem_free(name, MQ_NAMELEN); return EMFILE; } /* Check for mqueue attributes */ if (SCARG(uap, attr)) { error = copyin(SCARG(uap, attr), &attr, sizeof(struct mq_attr)); if (error) { kmem_free(name, MQ_NAMELEN); return error; } if (attr.mq_maxmsg <= 0 || attr.mq_msgsize <= 0 || attr.mq_msgsize > mq_max_msgsize) { kmem_free(name, MQ_NAMELEN); return EINVAL; } attr.mq_curmsgs = 0; } else { memset(&attr, 0, sizeof(struct mq_attr)); attr.mq_maxmsg = mq_def_maxmsg; attr.mq_msgsize = MQ_DEF_MSGSIZE - sizeof(struct mq_msg); } /* * Allocate new mqueue, initialize data structures, * copy the name, attributes and set the flag. */ mq_new = kmem_zalloc(sizeof(struct mqueue), KM_SLEEP); mutex_init(&mq_new->mq_mtx, MUTEX_DEFAULT, IPL_NONE); cv_init(&mq_new->mq_send_cv, "mqsendcv"); cv_init(&mq_new->mq_recv_cv, "mqrecvcv"); TAILQ_INIT(&mq_new->mq_head); selinit(&mq_new->mq_rsel); selinit(&mq_new->mq_wsel); strlcpy(mq_new->mq_name, name, MQ_NAMELEN); memcpy(&mq_new->mq_attrib, &attr, sizeof(struct mq_attr)); mq_new->mq_attrib.mq_flags = oflag; /* Store mode and effective UID with GID */ mq_new->mq_mode = SCARG(uap, mode); mq_new->mq_euid = kauth_cred_geteuid(l->l_cred); mq_new->mq_egid = kauth_cred_getegid(l->l_cred); } /* Allocate file structure and descriptor */ error = fd_allocfile(&fp, &mqd); if (error) { if (mq_new) mqueue_destroy(mq_new); kmem_free(name, MQ_NAMELEN); return error; } fp->f_type = DTYPE_MQUEUE; fp->f_flag = (oflag & O_RDWR) ? (VREAD | VWRITE) : ((oflag & O_RDONLY) ? VREAD : VWRITE); fp->f_ops = &mqops; /* Look up for mqueue with such name */ mutex_enter(&mqlist_mtx); mq = mqueue_lookup(name); if (mq) { KASSERT(mutex_owned(&mq->mq_mtx)); /* Check if mqueue is not marked as unlinking */ if (mq->mq_attrib.mq_flags & MQ_UNLINK) { error = EACCES; goto exit; } /* Fail if O_EXCL is set, and mqueue already exists */ if ((oflag & O_CREAT) && (oflag & O_EXCL)) { error = EEXIST; goto exit; } /* Check the permission */ if (mqueue_access(l, mq, fp->f_flag)) { error = EACCES; goto exit; } } else { /* Fail if mqueue neither exists, nor we create it */ if ((oflag & O_CREAT) == 0) { mutex_exit(&mqlist_mtx); KASSERT(mq_new == NULL); fd_abort(p, fp, mqd); kmem_free(name, MQ_NAMELEN); return ENOENT; } /* Check the limit */ if (p->p_mqueue_cnt == mq_open_max) { error = EMFILE; goto exit; } /* Insert the queue to the list */ mq = mq_new; mutex_enter(&mq->mq_mtx); LIST_INSERT_HEAD(&mqueue_head, mq, mq_list); mq_new = NULL; } /* Increase the counters, and make descriptor ready */ p->p_mqueue_cnt++; mq->mq_refcnt++; fp->f_data = mq; exit: mutex_exit(&mq->mq_mtx); mutex_exit(&mqlist_mtx); if (mq_new) mqueue_destroy(mq_new); if (error) { fd_abort(p, fp, mqd); } else { fd_affix(p, fp, mqd); *retval = mqd; } kmem_free(name, MQ_NAMELEN); return error; } int sys_mq_close(struct lwp *l, const struct sys_mq_close_args *uap, register_t *retval) { return sys_close(l, (const void *)uap, retval); } /* * Primary mq_receive1() function. */ static int mq_receive1(struct lwp *l, mqd_t mqdes, void *msg_ptr, size_t msg_len, unsigned *msg_prio, int t, ssize_t *mlen) { file_t *fp = NULL; struct mqueue *mq; struct mq_msg *msg = NULL; int error; /* Get the message queue */ error = mqueue_get(l, mqdes, VREAD, &fp); if (error) return error; mq = fp->f_data; /* Check the message size limits */ if (msg_len < mq->mq_attrib.mq_msgsize) { error = EMSGSIZE; goto error; } /* Check if queue is empty */ while (TAILQ_EMPTY(&mq->mq_head)) { if (mq->mq_attrib.mq_flags & O_NONBLOCK) { error = EAGAIN; goto error; } if (t < 0) { error = EINVAL; goto error; } /* * Block until someone sends the message. * While doing this, notification should not be sent. */ mq->mq_attrib.mq_flags |= MQ_RECEIVE; error = cv_timedwait_sig(&mq->mq_send_cv, &mq->mq_mtx, t); mq->mq_attrib.mq_flags &= ~MQ_RECEIVE; if (error || (mq->mq_attrib.mq_flags & MQ_UNLINK)) { error = (error == EWOULDBLOCK) ? ETIMEDOUT : EINTR; goto error; } } /* Remove the message from the queue */ msg = TAILQ_FIRST(&mq->mq_head); KASSERT(msg != NULL); TAILQ_REMOVE(&mq->mq_head, msg, msg_queue); /* Decrement the counter and signal waiter, if any */ mq->mq_attrib.mq_curmsgs--; cv_signal(&mq->mq_recv_cv); /* Ready for sending now */ selnotify(&mq->mq_wsel, POLLOUT | POLLWRNORM, 0); error: mutex_exit(&mq->mq_mtx); fd_putfile((int)mqdes); if (error) return error; /* * Copy the data to the user-space. * Note: According to POSIX, no message should be removed from the * queue in case of fail - this would be violated. */ *mlen = msg->msg_len; error = copyout(msg->msg_ptr, msg_ptr, msg->msg_len); if (error == 0 && msg_prio) error = copyout(&msg->msg_prio, msg_prio, sizeof(unsigned)); mqueue_freemsg(msg, sizeof(struct mq_msg) + msg->msg_len); return error; } int sys_mq_receive(struct lwp *l, const struct sys_mq_receive_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(char *) msg_ptr; syscallarg(size_t) msg_len; syscallarg(unsigned *) msg_prio; } */ int error; ssize_t mlen; error = mq_receive1(l, SCARG(uap, mqdes), SCARG(uap, msg_ptr), SCARG(uap, msg_len), SCARG(uap, msg_prio), 0, &mlen); if (error == 0) *retval = mlen; return error; } int sys_mq_timedreceive(struct lwp *l, const struct sys_mq_timedreceive_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(char *) msg_ptr; syscallarg(size_t) msg_len; syscallarg(unsigned *) msg_prio; syscallarg(const struct timespec *) abs_timeout; } */ int error, t; ssize_t mlen; /* Get and convert time value */ if (SCARG(uap, abs_timeout)) { error = abstimeout2timo(SCARG(uap, abs_timeout), &t); if (error) return error; } else t = 0; error = mq_receive1(l, SCARG(uap, mqdes), SCARG(uap, msg_ptr), SCARG(uap, msg_len), SCARG(uap, msg_prio), t, &mlen); if (error == 0) *retval = mlen; return error; } /* * Primary mq_send1() function. */ static int mq_send1(struct lwp *l, mqd_t mqdes, const char *msg_ptr, size_t msg_len, unsigned msg_prio, int t) { file_t *fp = NULL; struct mqueue *mq; struct mq_msg *msg, *pos_msg; struct proc *notify = NULL; ksiginfo_t ksi; size_t size; int error; /* Check the priority range */ if (msg_prio >= mq_prio_max) return EINVAL; /* Allocate a new message */ size = sizeof(struct mq_msg) + msg_len; if (size > mq_max_msgsize) return EMSGSIZE; if (size > MQ_DEF_MSGSIZE) msg = kmem_alloc(size, KM_SLEEP); else msg = pool_cache_get(mqmsg_cache, PR_WAITOK); /* Get the data from user-space */ error = copyin(msg_ptr, msg->msg_ptr, msg_len); if (error) { mqueue_freemsg(msg, size); return error; } msg->msg_len = msg_len; msg->msg_prio = msg_prio; /* Get the mqueue */ error = mqueue_get(l, mqdes, VWRITE, &fp); if (error) { mqueue_freemsg(msg, size); return error; } mq = fp->f_data; /* Check the message size limit */ if (msg_len <= 0 || msg_len > mq->mq_attrib.mq_msgsize) { error = EMSGSIZE; goto error; } /* Check if queue is full */ while (mq->mq_attrib.mq_curmsgs >= mq->mq_attrib.mq_maxmsg) { if (mq->mq_attrib.mq_flags & O_NONBLOCK) { error = EAGAIN; goto error; } if (t < 0) { error = EINVAL; goto error; } /* Block until queue becomes available */ error = cv_timedwait_sig(&mq->mq_recv_cv, &mq->mq_mtx, t); if (error || (mq->mq_attrib.mq_flags & MQ_UNLINK)) { error = (error == EWOULDBLOCK) ? ETIMEDOUT : error; goto error; } } KASSERT(mq->mq_attrib.mq_curmsgs < mq->mq_attrib.mq_maxmsg); /* Insert message into the queue, according to the priority */ TAILQ_FOREACH(pos_msg, &mq->mq_head, msg_queue) if (msg->msg_prio > pos_msg->msg_prio) break; if (pos_msg == NULL) TAILQ_INSERT_TAIL(&mq->mq_head, msg, msg_queue); else TAILQ_INSERT_BEFORE(pos_msg, msg, msg_queue); /* Check for the notify */ if (mq->mq_attrib.mq_curmsgs == 0 && mq->mq_notify_proc && (mq->mq_attrib.mq_flags & MQ_RECEIVE) == 0) { /* Initialize the signal */ KSI_INIT(&ksi); ksi.ksi_signo = mq->mq_sig_notify.sigev_signo; ksi.ksi_code = SI_MESGQ; ksi.ksi_value = mq->mq_sig_notify.sigev_value; /* Unregister the process */ notify = mq->mq_notify_proc; mq->mq_notify_proc = NULL; } /* Increment the counter and signal waiter, if any */ mq->mq_attrib.mq_curmsgs++; cv_signal(&mq->mq_send_cv); /* Ready for receiving now */ selnotify(&mq->mq_rsel, POLLIN | POLLRDNORM, 0); error: mutex_exit(&mq->mq_mtx); fd_putfile((int)mqdes); if (error) { mqueue_freemsg(msg, size); } else if (notify) { /* Send the notify, if needed */ mutex_enter(proc_lock); kpsignal(notify, &ksi, NULL); mutex_exit(proc_lock); } return error; } int sys_mq_send(struct lwp *l, const struct sys_mq_send_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(const char *) msg_ptr; syscallarg(size_t) msg_len; syscallarg(unsigned) msg_prio; } */ return mq_send1(l, SCARG(uap, mqdes), SCARG(uap, msg_ptr), SCARG(uap, msg_len), SCARG(uap, msg_prio), 0); } int sys_mq_timedsend(struct lwp *l, const struct sys_mq_timedsend_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(const char *) msg_ptr; syscallarg(size_t) msg_len; syscallarg(unsigned) msg_prio; syscallarg(const struct timespec *) abs_timeout; } */ int t; /* Get and convert time value */ if (SCARG(uap, abs_timeout)) { int error = abstimeout2timo(SCARG(uap, abs_timeout), &t); if (error) return error; } else t = 0; return mq_send1(l, SCARG(uap, mqdes), SCARG(uap, msg_ptr), SCARG(uap, msg_len), SCARG(uap, msg_prio), t); } int sys_mq_notify(struct lwp *l, const struct sys_mq_notify_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(const struct sigevent *) notification; } */ file_t *fp = NULL; struct mqueue *mq; struct sigevent sig; int error; if (SCARG(uap, notification)) { /* Get the signal from user-space */ error = copyin(SCARG(uap, notification), &sig, sizeof(struct sigevent)); if (error) return error; } error = mqueue_get(l, SCARG(uap, mqdes), VNOVAL, &fp); if (error) return error; mq = fp->f_data; if (SCARG(uap, notification)) { /* Register notification: set the signal and target process */ if (mq->mq_notify_proc == NULL) { memcpy(&mq->mq_sig_notify, &sig, sizeof(struct sigevent)); mq->mq_notify_proc = l->l_proc; } else { /* Fail if someone else already registered */ error = EBUSY; } } else { /* Unregister the notification */ mq->mq_notify_proc = NULL; } mutex_exit(&mq->mq_mtx); fd_putfile((int)SCARG(uap, mqdes)); return error; } int sys_mq_getattr(struct lwp *l, const struct sys_mq_getattr_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(struct mq_attr *) mqstat; } */ file_t *fp = NULL; struct mqueue *mq; struct mq_attr attr; int error; /* Get the message queue */ error = mqueue_get(l, SCARG(uap, mqdes), VNOVAL, &fp); if (error) return error; mq = fp->f_data; memcpy(&attr, &mq->mq_attrib, sizeof(struct mq_attr)); mutex_exit(&mq->mq_mtx); fd_putfile((int)SCARG(uap, mqdes)); return copyout(&attr, SCARG(uap, mqstat), sizeof(struct mq_attr)); } int sys_mq_setattr(struct lwp *l, const struct sys_mq_setattr_args *uap, register_t *retval) { /* { syscallarg(mqd_t) mqdes; syscallarg(const struct mq_attr *) mqstat; syscallarg(struct mq_attr *) omqstat; } */ file_t *fp = NULL; struct mqueue *mq; struct mq_attr attr; int error, nonblock; error = copyin(SCARG(uap, mqstat), &attr, sizeof(struct mq_attr)); if (error) return error; nonblock = (attr.mq_flags & O_NONBLOCK); /* Get the message queue */ error = mqueue_get(l, SCARG(uap, mqdes), VNOVAL, &fp); if (error) return error; mq = fp->f_data; /* Copy the old attributes, if needed */ if (SCARG(uap, omqstat)) memcpy(&attr, &mq->mq_attrib, sizeof(struct mq_attr)); /* Ignore everything, except O_NONBLOCK */ if (nonblock) mq->mq_attrib.mq_flags |= O_NONBLOCK; else mq->mq_attrib.mq_flags &= ~O_NONBLOCK; mutex_exit(&mq->mq_mtx); fd_putfile((int)SCARG(uap, mqdes)); /* * Copy the data to the user-space. * Note: According to POSIX, the new attributes should not be set in * case of fail - this would be violated. */ if (SCARG(uap, omqstat)) error = copyout(&attr, SCARG(uap, omqstat), sizeof(struct mq_attr)); return error; } int sys_mq_unlink(struct lwp *l, const struct sys_mq_unlink_args *uap, register_t *retval) { /* { syscallarg(const char *) name; } */ struct mqueue *mq; char *name; int error, refcnt = 0; /* Get the name from the user-space */ name = kmem_zalloc(MQ_NAMELEN, KM_SLEEP); error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL); if (error) { kmem_free(name, MQ_NAMELEN); return error; } /* Lookup for this file */ mutex_enter(&mqlist_mtx); mq = mqueue_lookup(name); if (mq == NULL) { error = ENOENT; goto error; } /* Check the permissions */ if (mqueue_access(l, mq, VWRITE)) { mutex_exit(&mq->mq_mtx); error = EACCES; goto error; } /* Mark message queue as unlinking, before leaving the window */ mq->mq_attrib.mq_flags |= MQ_UNLINK; /* Wake up all waiters, if there are such */ cv_broadcast(&mq->mq_send_cv); cv_broadcast(&mq->mq_recv_cv); selnotify(&mq->mq_rsel, POLLHUP, 0); selnotify(&mq->mq_wsel, POLLHUP, 0); refcnt = mq->mq_refcnt; if (refcnt == 0) LIST_REMOVE(mq, mq_list); mutex_exit(&mq->mq_mtx); error: mutex_exit(&mqlist_mtx); /* * If there are no references - destroy the message * queue, otherwise, the last mq_close() will do that. */ if (error == 0 && refcnt == 0) mqueue_destroy(mq); kmem_free(name, MQ_NAMELEN); return error; } /* * SysCtl. */ SYSCTL_SETUP(sysctl_mqueue_setup, "sysctl mqueue setup") { const struct sysctlnode *node = NULL; sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "kern", NULL, NULL, 0, NULL, 0, CTL_KERN, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_IMMEDIATE, CTLTYPE_INT, "posix_msg", SYSCTL_DESCR("Version of IEEE Std 1003.1 and its " "Message Passing option to which the " "system attempts to conform"), NULL, _POSIX_MESSAGE_PASSING, NULL, 0, CTL_KERN, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, NULL, &node, CTLFLAG_PERMANENT, CTLTYPE_NODE, "mqueue", SYSCTL_DESCR("Message queue options"), NULL, 0, NULL, 0, CTL_KERN, CTL_CREATE, CTL_EOL); if (node == NULL) return; sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "mq_open_max", SYSCTL_DESCR("Maximal number of message queue descriptors " "that process could open"), NULL, 0, &mq_open_max, 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "mq_prio_max", SYSCTL_DESCR("Maximal priority of the message"), NULL, 0, &mq_prio_max, 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "mq_max_msgsize", SYSCTL_DESCR("Maximal allowed size of the message"), NULL, 0, &mq_max_msgsize, 0, CTL_CREATE, CTL_EOL); sysctl_createv(clog, 0, &node, NULL, CTLFLAG_PERMANENT | CTLFLAG_READWRITE, CTLTYPE_INT, "mq_def_maxmsg", SYSCTL_DESCR("Default maximal message count"), NULL, 0, &mq_def_maxmsg, 0, CTL_CREATE, CTL_EOL); } /* * Debugging. */ #if defined(DDB) void mqueue_print_list(void (*pr)(const char *, ...)) { struct mqueue *mq; (*pr)("Global list of the message queues:\n"); (*pr)("%20s %10s %8s %8s %3s %4s %4s %4s\n", "Name", "Ptr", "Mode", "Flags", "Ref", "MaxMsg", "MsgSze", "CurMsg"); LIST_FOREACH(mq, &mqueue_head, mq_list) { (*pr)("%20s %10p %8x %8x %3u %6lu %6lu %6lu\n", mq->mq_name, mq, mq->mq_mode, mq->mq_attrib.mq_flags, mq->mq_refcnt, mq->mq_attrib.mq_maxmsg, mq->mq_attrib.mq_msgsize, mq->mq_attrib.mq_curmsgs); } } #endif /* defined(DDB) */