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/* Copyright 2002, Red Hat Inc. */
#include <mqueue.h>
#include <errno.h>
#include <sys/sem.h>
#include <string.h>
#define _LIBC 1
#include <sys/lock.h>
#undef _LIBC
#include "mqlocal.h"
int
mq_setattr (mqd_t msgid, const struct mq_attr *mqstat, struct mq_attr *omqstat)
{
struct libc_mq *info;
struct sembuf sb0 = {0, -1, 0};
int num_msgs;
int rc = 0;
info = __find_mq (msgid);
if (info == NULL)
{
errno = EBADF;
return -1;
}
/* temporarily lock message queue */
semop (info->semid, &sb0, 1);
/* make copy of old structure */
if (omqstat != NULL)
{
num_msgs = semctl (info->semid, 3, GETVAL);
if (num_msgs >= 0)
{
memcpy (omqstat, info->attr, sizeof(struct mq_attr));
omqstat->mq_curmsgs = num_msgs;
}
else
rc = -1;
}
/* only the mq_flags field can be changed */
info->attr->mq_flags = mqstat->mq_flags;
/* release message queue */
sb0.sem_op = 1;
semop (info->semid, &sb0, 1);
return rc;
}
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