60 lines
1003 B
C
60 lines
1003 B
C
/* Copyright 2002, Red Hat Inc. */
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#include <mqueue.h>
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#include <errno.h>
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#include <sys/sem.h>
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#include <string.h>
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#define _LIBC 1
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#include <sys/lock.h>
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#undef _LIBC
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#include "mqlocal.h"
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int
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mq_setattr (mqd_t msgid, const struct mq_attr *mqstat, struct mq_attr *omqstat)
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{
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struct libc_mq *info;
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struct sembuf sb0 = {0, -1, 0};
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int num_msgs;
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int rc = 0;
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info = __find_mq (msgid);
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if (info == NULL)
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{
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errno = EBADF;
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return -1;
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}
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/* temporarily lock message queue */
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semop (info->semid, &sb0, 1);
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/* make copy of old structure */
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if (omqstat != NULL)
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{
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num_msgs = semctl (info->semid, 3, GETVAL);
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if (num_msgs >= 0)
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{
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memcpy (omqstat, info->attr, sizeof(struct mq_attr));
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omqstat->mq_curmsgs = num_msgs;
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}
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else
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rc = -1;
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}
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/* only the mq_flags field can be changed */
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info->attr->mq_flags = mqstat->mq_flags;
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/* release message queue */
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sb0.sem_op = 1;
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semop (info->semid, &sb0, 1);
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return rc;
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}
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