1 files changed, 67 insertions, 0 deletions
diff --git a/newlib/libc/sys/linux/mq_receive.c b/newlib/libc/sys/linux/mq_receive.c
new file mode 100644
index 000000000..1aa7b9fb3
--- /dev/null
+++ b/newlib/libc/sys/linux/mq_receive.c
@@ -0,0 +1,67 @@
+/* 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>
+#define _LIBC
+#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;
+}
+      
+
+
+
+
+