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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;

}