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/*
* pipe.c: anonymous pipe
*
* Author: Wei Shen <cquark@gmail.com>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
#include <stdio.h>
#include <fcntl.h>
#include <rtems/libio_.h>
#include <rtems/seterr.h>
/* Incremental number added to names of anonymous pipe files */
uint16_t rtems_pipe_no = 0;
/*
* Called by pipe() to create an anonymous pipe.
*/
int pipe_create(
int filsdes[2]
)
{
rtems_filesystem_location_info_t loc;
rtems_libio_t *iop;
int err = 0;
/* Create /tmp if not exists */
if (rtems_filesystem_evaluate_path("/tmp", RTEMS_LIBIO_PERMS_RWX, &loc, TRUE)
!= 0) {
if (errno != ENOENT)
return -1;
if (mkdir("/tmp", S_IRWXU|S_IRWXG|S_IRWXO|S_ISVTX) != 0)
return -1;
}
else
rtems_filesystem_freenode(&loc);
/* /tmp/.fifoXXXX */
char fifopath[15];
memcpy(fifopath, "/tmp/.fifo", 10);
sprintf(fifopath + 10, "%04x", rtems_pipe_no ++);
/* Try creating FIFO file until find an available file name */
while (mkfifo(fifopath, S_IRUSR|S_IWUSR) != 0) {
if (errno != EEXIST)
return -1;
/* Just try once... */
return -1;
sprintf(fifopath + 10, "%04x", rtems_pipe_no ++);
}
/* Non-blocking open to avoid waiting for writers */
filsdes[0] = open(fifopath, O_RDONLY | O_NONBLOCK);
if (filsdes[0] < 0) {
err = errno;
goto out;
}
/* Reset open file to blocking mode */
iop = rtems_libio_iop(filsdes[0]);
iop->flags &= ~LIBIO_FLAGS_NO_DELAY;
filsdes[1] = open(fifopath, O_WRONLY);
if (filsdes[1] < 0) {
err = errno;
close(filsdes[0]);
}
out:
/* Delete file at errors, or else if pipe is successfully created
the file node will be deleted after it is closed by all. */
unlink(fifopath);
if (! err)
return 0;
rtems_set_errno_and_return_minus_one(err);
}
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