1 /* Copyright 2002, Red Hat Inc. */
2
3 #include <mqueue.h>
4 #include <errno.h>
5 #include <sys/sem.h>
6 #include <string.h>
7 #define _LIBC 1
8 #include <sys/lock.h>
9 #undef _LIBC
10
11 #include "mqlocal.h"
12
13 int
mq_getattr(mqd_t msgid,struct mq_attr * mqstat)14 mq_getattr (mqd_t msgid, struct mq_attr *mqstat)
15 {
16 struct libc_mq *info;
17 struct sembuf sb0 = {0, -1, 0};
18 int num_msgs;
19 int rc = 0;
20
21 info = __find_mq (msgid);
22
23 if (info == NULL)
24 {
25 errno = EBADF;
26 return -1;
27 }
28
29 /* temporarily lock message queue */
30 semop (info->semid, &sb0, 1);
31
32 num_msgs = semctl (info->semid, 3, GETVAL);
33 if (num_msgs >= 0)
34 {
35 memcpy (mqstat, info->attr, sizeof(struct mq_attr));
36 mqstat->mq_curmsgs = num_msgs;
37 }
38 else
39 rc = -1;
40
41 /* release message queue */
42 sb0.sem_op = 1;
43 semop (info->semid, &sb0, 1);
44
45 return rc;
46 }
47
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