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/* Copyright 2002, Red Hat Inc. */
#include <mqueue.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <string.h>
#include <stdlib.h>
#define _LIBC 1
#include <sys/lock.h>
#undef _LIBC
#include "mqlocal.h"
__LOCK_INIT(static, mq_wrbuf_lock);
int
mq_send (mqd_t msgid, const char *msg, size_t msg_len, unsigned int msg_prio)
{
struct libc_mq *info;
struct sembuf sb2 = {2, -1, 0};
struct sembuf sb3 = {3, 1, 0};
int rc;
int ipcflag;
info = __find_mq (msgid);
if (info == NULL || (info->oflag & O_ACCMODE) == O_RDONLY)
{
errno = EBADF;
return -1;
}
if (msg_len > info->attr->mq_msgsize)
{
errno = EMSGSIZE;
return -1;
}
if (msg_prio > MQ_PRIO_MAX)
{
errno = EINVAL;
return -1;
}
__lock_acquire (mq_wrbuf_lock);
memcpy (info->wrbuf->text, msg, msg_len);
info->wrbuf->type = (MQ_PRIO_MAX - msg_prio);
ipcflag = (info->attr->mq_flags & O_NONBLOCK) ? IPC_NOWAIT : 0;
sb2.sem_flg = ipcflag;
/* check to see if max msgs are on queue */
rc = semop (info->semid, &sb2, 1);
if (rc == 0)
rc = msgsnd (info->msgqid, info->wrbuf, msg_len, ipcflag);
if (rc == 0)
semop (info->semid, &sb3, 1); /* increment number of reads */
__lock_release (mq_wrbuf_lock);
return rc;
}
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