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NetBSD/sys/kern/sys_mqueue.c

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/* $NetBSD: sys_mqueue.c,v 1.11 2008/07/02 20:06:09 rmind Exp $ */
/*
* Copyright (c) 2007, 2008 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 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sys_mqueue.c,v 1.11 2008/07/02 20:06:09 rmind Exp $");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/condvar.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/filedesc.h>
#include <sys/kauth.h>
#include <sys/kernel.h>
#include <sys/kmem.h>
#include <sys/lwp.h>
#include <sys/mqueue.h>
#include <sys/mutex.h>
#include <sys/pool.h>
#include <sys/poll.h>
#include <sys/proc.h>
#include <sys/queue.h>
#include <sys/select.h>
#include <sys/signal.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
#include <sys/syscallargs.h>
#include <sys/systm.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
/* 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 = FFLAGS(oflag) & (FREAD | FWRITE);
fp->f_ops = &mqops;
/* Look up for mqueue with such name */
mutex_enter(&mqlist_mtx);
mq = mqueue_lookup(name);
if (mq) {
const int acc_mode = (oflag & O_RDWR) ? (VREAD | VWRITE) :
((oflag & O_RDONLY) ? VREAD : VWRITE);
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, acc_mode)) {
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) */
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