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NetBSD/sys/kern/sys_mqueue.c

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/* $NetBSD: sys_mqueue.c,v 1.39 2015/06/29 15:44:45 christos Exp $ */
/*
* Copyright (c) 2007-2011 Mindaugas Rasiukevicius <rmind at NetBSD org>
* 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 (mqueue_head) is protected by mqlist_lock.
* Each message queue and its members are protected by mqueue::mq_mtx.
* Note that proc_t::p_mqueue_cnt is updated atomically.
*
* Lock order:
*
* mqlist_lock ->
* mqueue::mq_mtx
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sys_mqueue.c,v 1.39 2015/06/29 15:44:45 christos Exp $");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/atomic.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kauth.h>
#include <sys/lwp.h>
#include <sys/mqueue.h>
#include <sys/module.h>
#include <sys/poll.h>
#include <sys/select.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/syscall.h>
#include <sys/syscallvar.h>
#include <sys/syscallargs.h>
#include <miscfs/genfs/genfs.h>
MODULE(MODULE_CLASS_MISC, mqueue, NULL);
/* 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 u_int mq_max_maxmsg = 16 * 32;
static pool_cache_t mqmsg_cache __read_mostly;
static kmutex_t mqlist_lock __cacheline_aligned;
static LIST_HEAD(, mqueue) mqueue_head __cacheline_aligned;
static struct sysctllog * mqsysctl_log;
static kauth_listener_t mq_listener;
static int mqueue_sysinit(void);
static int mqueue_sysfini(bool);
static int mqueue_sysctl_init(void);
static int mq_poll_fop(file_t *, int);
static int mq_stat_fop(file_t *, struct stat *);
static int mq_close_fop(file_t *);
static const struct fileops mqops = {
.fo_read = fbadop_read,
.fo_write = fbadop_write,
.fo_ioctl = fbadop_ioctl,
.fo_fcntl = fnullop_fcntl,
.fo_poll = mq_poll_fop,
.fo_stat = mq_stat_fop,
.fo_close = mq_close_fop,
.fo_kqfilter = fnullop_kqfilter,
.fo_restart = fnullop_restart,
};
static const struct syscall_package mqueue_syscalls[] = {
{ SYS_mq_open, 0, (sy_call_t *)sys_mq_open },
{ SYS_mq_close, 0, (sy_call_t *)sys_mq_close },
{ SYS_mq_unlink, 0, (sy_call_t *)sys_mq_unlink },
{ SYS_mq_getattr, 0, (sy_call_t *)sys_mq_getattr },
{ SYS_mq_setattr, 0, (sy_call_t *)sys_mq_setattr },
{ SYS_mq_notify, 0, (sy_call_t *)sys_mq_notify },
{ SYS_mq_send, 0, (sy_call_t *)sys_mq_send },
{ SYS_mq_receive, 0, (sy_call_t *)sys_mq_receive },
{ SYS___mq_timedsend50, 0, (sy_call_t *)sys___mq_timedsend50 },
{ SYS___mq_timedreceive50, 0, (sy_call_t *)sys___mq_timedreceive50 },
{ 0, 0, NULL }
};
static int
mq_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
void *arg0, void *arg1, void *arg2, void *arg3)
{
mqueue_t *mq;
int result;
if (action != KAUTH_SYSTEM_MQUEUE)
return KAUTH_RESULT_DEFER;
result = KAUTH_RESULT_DEFER;
mq = arg1;
if (kauth_cred_geteuid(cred) == mq->mq_euid)
result = KAUTH_RESULT_ALLOW;
return result;
}
/*
* Initialisation and unloading of POSIX message queue subsystem.
*/
static int
mqueue_sysinit(void)
{
int error;
mqmsg_cache = pool_cache_init(MQ_DEF_MSGSIZE, coherency_unit,
0, 0, "mqmsgpl", NULL, IPL_NONE, NULL, NULL, NULL);
mutex_init(&mqlist_lock, MUTEX_DEFAULT, IPL_NONE);
LIST_INIT(&mqueue_head);
error = mqueue_sysctl_init();
if (error) {
(void)mqueue_sysfini(false);
return error;
}
error = syscall_establish(NULL, mqueue_syscalls);
if (error) {
(void)mqueue_sysfini(false);
}
mq_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM,
mq_listener_cb, NULL);
return error;
}
static int
mqueue_sysfini(bool interface)
{
if (interface) {
int error;
bool inuse;
/* Stop syscall activity. */
error = syscall_disestablish(NULL, mqueue_syscalls);
if (error)
return error;
/* Check if there are any message queues in use. */
mutex_enter(&mqlist_lock);
inuse = !LIST_EMPTY(&mqueue_head);
mutex_exit(&mqlist_lock);
if (inuse) {
error = syscall_establish(NULL, mqueue_syscalls);
KASSERT(error == 0);
return EBUSY;
}
}
if (mqsysctl_log != NULL)
sysctl_teardown(&mqsysctl_log);
kauth_unlisten_scope(mq_listener);
mutex_destroy(&mqlist_lock);
pool_cache_destroy(mqmsg_cache);
return 0;
}
/*
* Module interface.
*/
static int
mqueue_modcmd(modcmd_t cmd, void *arg)
{
switch (cmd) {
case MODULE_CMD_INIT:
return mqueue_sysinit();
case MODULE_CMD_FINI:
return mqueue_sysfini(true);
default:
return ENOTTY;
}
}
/*
* 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;
size_t msz;
u_int i;
/* Note MQ_PQSIZE + 1. */
for (i = 0; i <= MQ_PQSIZE; i++) {
while ((msg = TAILQ_FIRST(&mq->mq_head[i])) != NULL) {
TAILQ_REMOVE(&mq->mq_head[i], msg, msg_queue);
msz = sizeof(struct mq_msg) + msg->msg_len;
mqueue_freemsg(msg, msz);
}
}
if (mq->mq_name) {
kmem_free(mq->mq_name, MQ_NAMELEN);
}
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));
}
/*
* mqueue_lookup: lookup for file name in general list of message queues.
*
* => locks the message queue on success
*/
static mqueue_t *
mqueue_lookup(const char *name)
{
mqueue_t *mq;
KASSERT(mutex_owned(&mqlist_lock));
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;
}
/*
* mqueue_get: get the mqueue from the descriptor.
*
* => locks the message queue, if found.
* => holds a reference on the file descriptor.
*/
int
mqueue_get(mqd_t mqd, int fflag, mqueue_t **mqret)
{
const int fd = (int)mqd;
mqueue_t *mq;
file_t *fp;
fp = fd_getfile(fd);
if (__predict_false(fp == NULL)) {
return EBADF;
}
if (__predict_false(fp->f_type != DTYPE_MQUEUE)) {
fd_putfile(fd);
return EBADF;
}
if (fflag && (fp->f_flag & fflag) == 0) {
fd_putfile(fd);
return EBADF;
}
mq = fp->f_mqueue;
mutex_enter(&mq->mq_mtx);
*mqret = mq;
return 0;
}
/*
* mqueue_linear_insert: perform linear insert according to the message
* priority into the reserved queue (MQ_PQRESQ). Reserved queue is a
* sorted list used only when mq_prio_max is increased via sysctl.
*/
static inline void
mqueue_linear_insert(struct mqueue *mq, struct mq_msg *msg)
{
struct mq_msg *mit;
TAILQ_FOREACH(mit, &mq->mq_head[MQ_PQRESQ], msg_queue) {
if (msg->msg_prio > mit->msg_prio)
break;
}
if (mit == NULL) {
TAILQ_INSERT_TAIL(&mq->mq_head[MQ_PQRESQ], msg, msg_queue);
} else {
TAILQ_INSERT_BEFORE(mit, msg, msg_queue);
}
}
static int
mq_stat_fop(file_t *fp, struct stat *st)
{
struct mqueue *mq = fp->f_mqueue;
memset(st, 0, sizeof(*st));
mutex_enter(&mq->mq_mtx);
st->st_mode = mq->mq_mode;
st->st_uid = mq->mq_euid;
st->st_gid = mq->mq_egid;
st->st_atimespec = mq->mq_atime;
st->st_mtimespec = mq->mq_mtime;
st->st_ctimespec = st->st_birthtimespec = mq->mq_btime;
st->st_uid = kauth_cred_geteuid(fp->f_cred);
st->st_gid = kauth_cred_getegid(fp->f_cred);
mutex_exit(&mq->mq_mtx);
return 0;
}
static int
mq_poll_fop(file_t *fp, int events)
{
struct mqueue *mq = fp->f_mqueue;
struct mq_attr *mqattr;
int revents = 0;
mutex_enter(&mq->mq_mtx);
mqattr = &mq->mq_attrib;
if (events & (POLLIN | POLLRDNORM)) {
/* Ready for receiving, if there are messages in the queue. */
if (mqattr->mq_curmsgs)
revents |= events & (POLLIN | POLLRDNORM);
else
selrecord(curlwp, &mq->mq_rsel);
}
if (events & (POLLOUT | POLLWRNORM)) {
/* Ready for sending, if the message queue is not full. */
if (mqattr->mq_curmsgs < mqattr->mq_maxmsg)
revents |= events & (POLLOUT | POLLWRNORM);
else
selrecord(curlwp, &mq->mq_wsel);
}
mutex_exit(&mq->mq_mtx);
return revents;
}
static int
mq_close_fop(file_t *fp)
{
proc_t *p = curproc;
mqueue_t *mq = fp->f_mqueue;
bool destroy = false;
mutex_enter(&mq->mq_mtx);
KASSERT(mq->mq_refcnt > 0);
if (--mq->mq_refcnt == 0) {
/* Destroy if the last reference and unlinked. */
destroy = (mq->mq_attrib.mq_flags & MQ_UNLINKED) != 0;
}
mutex_exit(&mq->mq_mtx);
if (destroy) {
mqueue_destroy(mq);
}
atomic_dec_uint(&p->p_mqueue_cnt);
return 0;
}
static int
mqueue_access(mqueue_t *mq, int access, kauth_cred_t cred)
{
mode_t acc_mode = 0;
/* Note the difference between VREAD/VWRITE and FREAD/FWRITE. */
if (access & FREAD) {
acc_mode |= VREAD;
}
if (access & FWRITE) {
acc_mode |= VWRITE;
}
if (genfs_can_access(VNON, mq->mq_mode, mq->mq_euid,
mq->mq_egid, acc_mode, cred)) {
return EACCES;
}
return 0;
}
static int
mqueue_create(lwp_t *l, char *name, struct mq_attr *attr, mode_t mode,
int oflag, mqueue_t **mqret)
{
proc_t *p = l->l_proc;
struct cwdinfo *cwdi = p->p_cwdi;
mqueue_t *mq;
u_int i;
/* Pre-check the limit. */
if (p->p_mqueue_cnt >= mq_open_max) {
return EMFILE;
}
/* Empty name is invalid. */
if (name[0] == '\0') {
return EINVAL;
}
/* Check for mqueue attributes. */
if (attr) {
if (attr->mq_maxmsg <= 0 || attr->mq_maxmsg > mq_max_maxmsg ||
attr->mq_msgsize <= 0 ||
attr->mq_msgsize > mq_max_msgsize) {
return EINVAL;
}
attr->mq_curmsgs = 0;
}
/*
* Allocate new message queue, initialize data structures, copy the
* name attributes. Note that the initial reference is set here.
*/
mq = kmem_zalloc(sizeof(mqueue_t), KM_SLEEP);
mutex_init(&mq->mq_mtx, MUTEX_DEFAULT, IPL_NONE);
cv_init(&mq->mq_send_cv, "mqsendcv");
cv_init(&mq->mq_recv_cv, "mqrecvcv");
for (i = 0; i < (MQ_PQSIZE + 1); i++) {
TAILQ_INIT(&mq->mq_head[i]);
}
selinit(&mq->mq_rsel);
selinit(&mq->mq_wsel);
mq->mq_name = name;
mq->mq_refcnt = 1;
if (attr != NULL) {
memcpy(&mq->mq_attrib, attr, sizeof(struct mq_attr));
} else {
memset(&mq->mq_attrib, 0, sizeof(struct mq_attr));
mq->mq_attrib.mq_maxmsg = mq_def_maxmsg;
mq->mq_attrib.mq_msgsize = MQ_DEF_MSGSIZE - sizeof(struct mq_msg);
}
CTASSERT((O_MASK & (MQ_UNLINKED | MQ_RECEIVE)) == 0);
mq->mq_attrib.mq_flags = (O_MASK & oflag);
/* Store mode and effective UID with GID. */
mq->mq_mode = ((mode & ~cwdi->cwdi_cmask) & ALLPERMS) & ~S_ISTXT;
mq->mq_euid = kauth_cred_geteuid(l->l_cred);
mq->mq_egid = kauth_cred_getegid(l->l_cred);
*mqret = mq;
return 0;
}
/*
* Helper function for mq_open() - note that "u_name" is a userland pointer,
* while "attr" is a kernel pointer!
*/
int
mq_handle_open(struct lwp *l, const char *u_name, int oflag, mode_t mode,
struct mq_attr *attr, register_t *retval)
{
struct proc *p = l->l_proc;
struct mqueue *mq, *mq_new = NULL;
int mqd, error;
file_t *fp;
char *name;
/* Get the name from the user-space. */
name = kmem_alloc(MQ_NAMELEN, KM_SLEEP);
error = copyinstr(u_name, name, MQ_NAMELEN - 1, NULL);
if (error) {
kmem_free(name, MQ_NAMELEN);
return error;
}
/* Allocate file structure and descriptor. */
error = fd_allocfile(&fp, &mqd);
if (error) {
kmem_free(name, MQ_NAMELEN);
return error;
}
fp->f_type = DTYPE_MQUEUE;
fp->f_flag = FFLAGS(oflag) & (FREAD | FWRITE);
fp->f_ops = &mqops;
if (oflag & O_CREAT) {
/* Create a new message queue. */
error = mqueue_create(l, name, attr, mode, oflag, &mq_new);
if (error) {
goto err;
}
KASSERT(mq_new != NULL);
}
/* Lookup for a message queue with such name. */
mutex_enter(&mqlist_lock);
mq = mqueue_lookup(name);
if (mq) {
KASSERT(mutex_owned(&mq->mq_mtx));
mutex_exit(&mqlist_lock);
/* Check for exclusive create. */
if (oflag & O_EXCL) {
mutex_exit(&mq->mq_mtx);
error = EEXIST;
goto err;
}
/* Verify permissions. */
if (mqueue_access(mq, fp->f_flag, l->l_cred) != 0) {
mutex_exit(&mq->mq_mtx);
error = EACCES;
goto err;
}
/* If we have the access, add a new reference. */
mq->mq_refcnt++;
mutex_exit(&mq->mq_mtx);
} else {
/* Fail if not found and not creating. */
if ((oflag & O_CREAT) == 0) {
mutex_exit(&mqlist_lock);
KASSERT(mq_new == NULL);
error = ENOENT;
goto err;
}
/* Account and check for the limit. */
if (atomic_inc_uint_nv(&p->p_mqueue_cnt) > mq_open_max) {
mutex_exit(&mqlist_lock);
atomic_dec_uint(&p->p_mqueue_cnt);
error = EMFILE;
goto err;
}
/* Initial timestamps. */
mq = mq_new;
getnanotime(&mq->mq_btime);
mq->mq_atime = mq->mq_mtime = mq->mq_btime;
/*
* Finally, insert message queue into the list.
* Note: it already has the initial reference.
*/
LIST_INSERT_HEAD(&mqueue_head, mq, mq_list);
mutex_exit(&mqlist_lock);
mq_new = NULL;
name = NULL;
}
KASSERT(mq != NULL);
fp->f_mqueue = mq;
fd_affix(p, fp, mqd);
*retval = mqd;
err:
if (error) {
fd_abort(p, fp, mqd);
}
if (mq_new) {
/* Note: will free the 'name'. */
mqueue_destroy(mq_new);
} else if (name) {
kmem_free(name, MQ_NAMELEN);
}
return error;
}
/*
* 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 mq_attr *attr = NULL, a;
int error;
if ((SCARG(uap, oflag) & O_CREAT) != 0 && SCARG(uap, attr) != NULL) {
error = copyin(SCARG(uap, attr), &a, sizeof(a));
if (error)
return error;
attr = &a;
}
return mq_handle_open(l, SCARG(uap, name), SCARG(uap, oflag),
SCARG(uap, mode), attr, retval);
}
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_recv1() function.
*/
int
mq_recv1(mqd_t mqdes, void *msg_ptr, size_t msg_len, u_int *msg_prio,
struct timespec *ts, ssize_t *mlen)
{
struct mqueue *mq;
struct mq_msg *msg = NULL;
struct mq_attr *mqattr;
u_int idx;
int error;
error = mqueue_get(mqdes, FREAD, &mq);
if (error) {
return error;
}
getnanotime(&mq->mq_atime);
mqattr = &mq->mq_attrib;
/* Check the message size limits */
if (msg_len < mqattr->mq_msgsize) {
error = EMSGSIZE;
goto error;
}
/* Check if queue is empty */
while (mqattr->mq_curmsgs == 0) {
int t;
if (mqattr->mq_flags & O_NONBLOCK) {
error = EAGAIN;
goto error;
}
if (ts) {
error = ts2timo(CLOCK_REALTIME, TIMER_ABSTIME, ts, &t,
NULL);
if (error)
goto error;
} else
t = 0;
/*
* Block until someone sends the message.
* While doing this, notification should not be sent.
*/
mqattr->mq_flags |= MQ_RECEIVE;
error = cv_timedwait_sig(&mq->mq_send_cv, &mq->mq_mtx, t);
mqattr->mq_flags &= ~MQ_RECEIVE;
if (error || (mqattr->mq_flags & MQ_UNLINKED)) {
error = (error == EWOULDBLOCK) ? ETIMEDOUT : EINTR;
goto error;
}
}
/*
* Find the highest priority message, and remove it from the queue.
* At first, reserved queue is checked, bitmap is next.
*/
msg = TAILQ_FIRST(&mq->mq_head[MQ_PQRESQ]);
if (__predict_true(msg == NULL)) {
idx = ffs(mq->mq_bitmap);
msg = TAILQ_FIRST(&mq->mq_head[idx]);
KASSERT(msg != NULL);
} else {
idx = MQ_PQRESQ;
}
TAILQ_REMOVE(&mq->mq_head[idx], msg, msg_queue);
/* Unmark the bit, if last message. */
if (__predict_true(idx) && TAILQ_EMPTY(&mq->mq_head[idx])) {
KASSERT((MQ_PQSIZE - idx) == msg->msg_prio);
mq->mq_bitmap &= ~(1 << --idx);
}
/* Decrement the counter and signal waiter, if any */
mqattr->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;
} */
ssize_t mlen;
int error;
error = mq_recv1(SCARG(uap, mqdes), SCARG(uap, msg_ptr),
SCARG(uap, msg_len), SCARG(uap, msg_prio), NULL, &mlen);
if (error == 0)
*retval = mlen;
return error;
}
int
sys___mq_timedreceive50(struct lwp *l,
const struct sys___mq_timedreceive50_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;
} */
struct timespec ts, *tsp;
ssize_t mlen;
int error;
/* Get and convert time value */
if (SCARG(uap, abs_timeout)) {
error = copyin(SCARG(uap, abs_timeout), &ts, sizeof(ts));
if (error)
return error;
tsp = &ts;
} else {
tsp = NULL;
}
error = mq_recv1(SCARG(uap, mqdes), SCARG(uap, msg_ptr),
SCARG(uap, msg_len), SCARG(uap, msg_prio), tsp, &mlen);
if (error == 0)
*retval = mlen;
return error;
}
/*
* Primary mq_send1() function.
*/
int
mq_send1(mqd_t mqdes, const char *msg_ptr, size_t msg_len, u_int msg_prio,
struct timespec *ts)
{
struct mqueue *mq;
struct mq_msg *msg;
struct mq_attr *mqattr;
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;
error = mqueue_get(mqdes, FWRITE, &mq);
if (error) {
mqueue_freemsg(msg, size);
return error;
}
getnanotime(&mq->mq_mtime);
mqattr = &mq->mq_attrib;
/* Check the message size limit */
if (msg_len <= 0 || msg_len > mqattr->mq_msgsize) {
error = EMSGSIZE;
goto error;
}
/* Check if queue is full */
while (mqattr->mq_curmsgs >= mqattr->mq_maxmsg) {
int t;
if (mqattr->mq_flags & O_NONBLOCK) {
error = EAGAIN;
goto error;
}
if (ts) {
error = ts2timo(CLOCK_REALTIME, TIMER_ABSTIME, ts, &t,
NULL);
if (error)
goto error;
} else
t = 0;
/* Block until queue becomes available */
error = cv_timedwait_sig(&mq->mq_recv_cv, &mq->mq_mtx, t);
if (error || (mqattr->mq_flags & MQ_UNLINKED)) {
error = (error == EWOULDBLOCK) ? ETIMEDOUT : error;
goto error;
}
}
KASSERT(mqattr->mq_curmsgs < mqattr->mq_maxmsg);
/*
* Insert message into the queue, according to the priority.
* Note the difference between index and priority.
*/
if (__predict_true(msg_prio < MQ_PQSIZE)) {
u_int idx = MQ_PQSIZE - msg_prio;
KASSERT(idx != MQ_PQRESQ);
TAILQ_INSERT_TAIL(&mq->mq_head[idx], msg, msg_queue);
mq->mq_bitmap |= (1 << --idx);
} else {
mqueue_linear_insert(mq, msg);
}
/* Check for the notify */
if (mqattr->mq_curmsgs == 0 && mq->mq_notify_proc &&
(mqattr->mq_flags & MQ_RECEIVE) == 0 &&
mq->mq_sig_notify.sigev_notify == SIGEV_SIGNAL) {
/* 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 */
mqattr->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(SCARG(uap, mqdes), SCARG(uap, msg_ptr),
SCARG(uap, msg_len), SCARG(uap, msg_prio), NULL);
}
int
sys___mq_timedsend50(struct lwp *l, const struct sys___mq_timedsend50_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;
} */
struct timespec ts, *tsp;
int error;
/* Get and convert time value */
if (SCARG(uap, abs_timeout)) {
error = copyin(SCARG(uap, abs_timeout), &ts, sizeof(ts));
if (error)
return error;
tsp = &ts;
} else {
tsp = NULL;
}
return mq_send1(SCARG(uap, mqdes), SCARG(uap, msg_ptr),
SCARG(uap, msg_len), SCARG(uap, msg_prio), tsp);
}
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;
} */
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;
if (sig.sigev_notify == SIGEV_SIGNAL &&
(sig.sigev_signo <=0 || sig.sigev_signo >= NSIG))
return EINVAL;
}
error = mqueue_get(SCARG(uap, mqdes), 0, &mq);
if (error) {
return error;
}
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;
} */
struct mqueue *mq;
struct mq_attr attr;
int error;
error = mqueue_get(SCARG(uap, mqdes), 0, &mq);
if (error) {
return error;
}
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;
} */
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);
error = mqueue_get(SCARG(uap, mqdes), 0, &mq);
if (error) {
return error;
}
/* 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;
} */
mqueue_t *mq;
char *name;
int error, refcnt = 0;
/* Get the name from the user-space */
name = kmem_alloc(MQ_NAMELEN, KM_SLEEP);
error = copyinstr(SCARG(uap, name), name, MQ_NAMELEN - 1, NULL);
if (error) {
kmem_free(name, MQ_NAMELEN);
return error;
}
mutex_enter(&mqlist_lock);
mq = mqueue_lookup(name);
if (mq == NULL) {
error = ENOENT;
goto err;
}
KASSERT(mutex_owned(&mq->mq_mtx));
/* Verify permissions. */
if (kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MQUEUE, 0, mq,
NULL, NULL)) {
mutex_exit(&mq->mq_mtx);
error = EACCES;
goto err;
}
/* Remove and destroy if no references. */
LIST_REMOVE(mq, mq_list);
refcnt = mq->mq_refcnt;
if (refcnt) {
/* Mark as unlinked, if there are references. */
mq->mq_attrib.mq_flags |= MQ_UNLINKED;
}
/* Wake up waiters, if there are any. */
cv_broadcast(&mq->mq_send_cv);
cv_broadcast(&mq->mq_recv_cv);
selnotify(&mq->mq_rsel, POLLHUP, 0);
selnotify(&mq->mq_wsel, POLLHUP, 0);
mutex_exit(&mq->mq_mtx);
err:
mutex_exit(&mqlist_lock);
/*
* If last reference - destroy the message queue. Otherwise,
* the last mq_close() call will do that.
*/
if (!error && refcnt == 0) {
mqueue_destroy(mq);
}
kmem_free(name, MQ_NAMELEN);
return error;
}
/*
* System control nodes.
*/
static int
mqueue_sysctl_init(void)
{
const struct sysctlnode *node = NULL;
mqsysctl_log = NULL;
sysctl_createv(&mqsysctl_log, 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(&mqsysctl_log, 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 ENXIO;
sysctl_createv(&mqsysctl_log, 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(&mqsysctl_log, 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(&mqsysctl_log, 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(&mqsysctl_log, 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);
sysctl_createv(&mqsysctl_log, 0, &node, NULL,
CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
CTLTYPE_INT, "mq_max_maxmsg",
SYSCTL_DESCR("Maximal allowed message count"),
NULL, 0, &mq_max_maxmsg, 0,
CTL_CREATE, CTL_EOL);
return 0;
}
/*
* 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) */
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