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/*
* NOTE: The structure of the routines is identical to that of POSIX
* Message_queues to leave the option of having unnamed message
* queues at a future date. They are currently not part of the
* POSIX standard but unnamed message_queues are. This is also
* the reason for the apparently unnecessary tracking of
* the process_shared attribute. [In addition to the fact that
* it would be trivial to add pshared to the mq_attr structure
* and have process private message queues.]
*
* This code ignores the O_RDONLY/O_WRONLY/O_RDWR flag at open
* time.
*
* $Id$
*/
#include <stdarg.h>
#include <pthread.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <mqueue.h>
#include <rtems/system.h>
#include <rtems/score/watchdog.h>
#include <rtems/posix/seterr.h>
#include <rtems/posix/mqueue.h>
#include <rtems/posix/time.h>
/*PAGE
*
* 15.2.2 Open a Message Queue, P1003.1b-1993, p. 272
*/
mqd_t mq_open(
const char *name,
int oflag,
...
/* mode_t mode, */
/* struct mq_attr attr */
)
{
va_list arg;
mode_t mode;
struct mq_attr *attr;
int status;
Objects_Id the_mq_id;
POSIX_Message_queue_Control *the_mq;
if ( oflag & O_CREAT ) {
va_start(arg, oflag);
mode = (mode_t) va_arg( arg, mode_t );
attr = (struct mq_attr *) va_arg( arg, struct mq_attr * );
va_end(arg);
}
status = _POSIX_Message_queue_Name_to_id( name, &the_mq_id );
/*
* If the name to id translation worked, then the message queue exists
* and we can just return a pointer to the id. Otherwise we may
* need to check to see if this is a "message queue does not exist"
* or some other miscellaneous error on the name.
*/
if ( status ) {
if ( status == EINVAL ) { /* name -> ID translation failed */
if ( !(oflag & O_CREAT) ) { /* willing to create it? */
set_errno_and_return_minus_one( ENOENT );
return (mqd_t) -1;
}
/* we are willing to create it */
}
set_errno_and_return_minus_one( status ); /* some type of error */
return (mqd_t) -1;
} else { /* name -> ID translation succeeded */
if ( (oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL) ) {
set_errno_and_return_minus_one( EEXIST );
return (mqd_t) -1;
}
/*
* XXX In this case we need to do an ID->pointer conversion to
* check the mode. This is probably a good place for a subroutine.
*/
the_mq->open_count += 1;
return (mqd_t)&the_mq->Object.id;
}
/* XXX verify this comment...
*
* At this point, the message queue does not exist and everything has been
* checked. We should go ahead and create a message queue.
*/
status = _POSIX_Message_queue_Create_support(
name,
TRUE, /* shared across processes */
oflag,
attr,
&the_mq
);
if ( status == -1 )
return (mqd_t) -1;
return (mqd_t) &the_mq->Object.id;
}
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