newlib-cygwin/newlib/libc/sys/linux/mq_receive.c

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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>
2002-07-15 Jeff Johnston <jjohnstn@redhat.com> * libc/sys/linux/Makefile.am: Add new files. * libc/sys/linux/Makefile.in: Regenerated. * libc/sys/linux/bp-sym.h: Moved to include directory. * libc/sys/linux/mmap.c: Add weak aliases: __mmap, __munmap, __mremap. * libc/sys/linux/inode.c: Set _LIBC to 1. * libc/sys/linux/mq_close.c: Ditto. * libc/sys/linux/mq_getattr.c: Ditto. * libc/sys/linux/mq_open.c: Ditto. * libc/sys/linux/mq_receive.c: Ditto. * libc/sys/linux/mq_send.c: Ditto. * libc/sys/linux/mq_setattr.c: Ditto. * libc/sys/linux/mq_unlink.c: Ditto. * libc/sys/linux/calloc.c: New file. * libc/sys/linux/callocr.c: Ditto. * libc/sys/linux/cfreer.c: Ditto. * libc/sys/linux/config.h: Ditto. * libc/sys/linux/free.c: Ditto. * libc/sys/linux/freer.c: Ditto. * libc/sys/linux/msize.c: Ditto. * libc/sys/linux/msizer.c: Ditto. * libc/sys/linux/mstats.c: Ditto. * libc/sys/linux/mtrim.c: Ditto. * libc/sys/linux/mtrimr.c: Ditto. * libc/sys/linux/pvallocr.c: Ditto. * libc/sys/linux/realloc.c: Ditto. * libc/sys/linux/reallocr.c: Ditto. * libc/sys/linux/thread-m.h: Ditto. * libc/sys/linux/vallocr.c: Ditto. * libc/sys/linux/bp-checks.h: Ditto. * libc/sys/linux/libc-symbols.h: Ditto. * libc/sys/linux/libc-tsd.h: Ditto. * libc/sys/linux/libintl.h: Ditto. * libc/sys/linux/malign.c: Ditto. * libc/sys/linux/malignr.c: Ditto. * libc/sys/linux/mallinfor.c: Ditto. * libc/sys/linux/malloc.c: Ditto. * libc/sys/linux/mallocr.c: Ditto. * libc/sys/linux/malloptr.c: Ditto. * libc/sys/linux/mallstatsr.c: Ditto. * libc/sys/linux/mcheck.c: Ditto. * libc/sys/linux/mhooks.h: Ditto. * libc/sys/linux/include/bp-sym.h: Ditto. * libc/sys/linux/include/malloc.h: Ditto. * libc/sys/linux/include/mcheck.h: Ditto. * libc/sys/linux/machine/i386/getpagesize.c: New file. * libc/sys/linux/machine/i386/Makefile.am: Add getpagesize.c. * libc/sys/linux/machine/i386/Makefile.in: Regenerated. * libc/sys/linux/machine/i386/sysdep.h: New file. * libc/sys/linux/machine/i386/weakalias.h: Add weak_function support. * libc/sys/linux/sys/dirent.h: Set _LIBC to 1. * libc/sys/linux/sys/types.h: Add new types.
2002-07-16 04:16:32 +08:00
#define _LIBC 1
#include <sys/lock.h>
#undef _LIBC
#include "mqlocal.h"
__LOCK_INIT(static, mq_rdbuf_lock);
ssize_t
mq_receive (mqd_t msgid, 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, IPC_NOWAIT};
struct sembuf sb5 = {5, 1, IPC_NOWAIT};
ssize_t num_bytes;
int ipcflag;
info = __find_mq (msgid);
if (info == NULL || (info->oflag & O_ACCMODE) == O_WRONLY)
{
errno = EBADF;
return -1;
}
if (msg_len < info->attr->mq_msgsize)
{
errno = EMSGSIZE;
return -1;
}
__lock_acquire (mq_rdbuf_lock);
ipcflag = (info->attr->mq_flags & O_NONBLOCK) ? IPC_NOWAIT : 0;
semop (info->semid, &sb5, 1); /* increase number of readers */
num_bytes = msgrcv (info->msgqid, info->rdbuf, msg_len, -MQ_PRIO_MAX, ipcflag);
sb5.sem_op = -1;
semop (info->semid, &sb5, 1); /* decrease number of readers */
if (num_bytes != (ssize_t)-1)
{
semop (info->semid, &sb2, 1); /* add one to messages left to write */
semop (info->semid, &sb3, 1); /* subtract one from messages to read */
memcpy (msg, info->rdbuf->text, num_bytes);
if (msg_prio != NULL)
*msg_prio = MQ_PRIO_MAX - info->rdbuf->type;
}
__lock_release (mq_rdbuf_lock);
return num_bytes;
}