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82 lines
1.9 KiB
C
82 lines
1.9 KiB
C
/*
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* pipe.c: anonymous pipe
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*
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* Author: Wei Shen <cquark@gmail.com>
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rtems.com/license/LICENSE.
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*
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* $Id$
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*/
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#include <stdio.h>
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#include <fcntl.h>
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#include <rtems/libio_.h>
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#include <rtems/seterr.h>
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/* Incremental number added to names of anonymous pipe files */
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uint16_t rtems_pipe_no = 0;
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/*
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* Called by pipe() to create an anonymous pipe.
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*/
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int pipe_create(
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int filsdes[2]
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)
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{
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rtems_filesystem_location_info_t loc;
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rtems_libio_t *iop;
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int err = 0;
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/* Create /tmp if not exists */
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if (rtems_filesystem_evaluate_path("/tmp", 3, RTEMS_LIBIO_PERMS_RWX, &loc, TRUE)
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!= 0) {
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if (errno != ENOENT)
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return -1;
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if (mkdir("/tmp", S_IRWXU|S_IRWXG|S_IRWXO|S_ISVTX) != 0)
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return -1;
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}
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else
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rtems_filesystem_freenode(&loc);
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/* /tmp/.fifoXXXX */
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char fifopath[15];
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memcpy(fifopath, "/tmp/.fifo", 10);
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sprintf(fifopath + 10, "%04x", rtems_pipe_no ++);
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/* Try creating FIFO file until find an available file name */
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while (mkfifo(fifopath, S_IRUSR|S_IWUSR) != 0) {
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if (errno != EEXIST){
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return -1;
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}
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/* Just try once... */
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return -1;
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sprintf(fifopath + 10, "%04x", rtems_pipe_no ++);
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}
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/* Non-blocking open to avoid waiting for writers */
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filsdes[0] = open(fifopath, O_RDONLY | O_NONBLOCK);
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if (filsdes[0] < 0) {
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err = errno;
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/* Delete file at errors, or else if pipe is successfully created
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the file node will be deleted after it is closed by all. */
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unlink(fifopath);
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}
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else {
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/* Reset open file to blocking mode */
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iop = rtems_libio_iop(filsdes[0]);
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iop->flags &= ~LIBIO_FLAGS_NO_DELAY;
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filsdes[1] = open(fifopath, O_WRONLY);
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if (filsdes[1] < 0) {
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err = errno;
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close(filsdes[0]);
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}
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unlink(fifopath);
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}
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rtems_set_errno_and_return_minus_one(err);
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}
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