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/*
* popen() for stdin, stdout and stderr.
*
* Based on popenRWE() by Bart Trojanowski.
*
* Copyright (C) 2012 Tobias Klauser <tklauser@distanz.ch>
* Copyright (C) 2009-2010 Bart Trojanowski <bart@jukie.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
/**
* Pipe stream to an application (like popen() but for std{in,out,err}).
*
* After successful return:
* - write to pipes[0] will go to stdin of the child
* - read from pipes[1] to get stdout of the child
* - read from pipes[2] to get stderr of the child
*
* @param cmd external command to execute
* @param pipes int array of three to write FDs for std{in,out,err} to
* @return PID of the executed application on success, -1 otherwise
*/
pid_t popen3(const char *cmd, int *pipes)
{
int in[2], out[2], err[2];
pid_t pid;
int ret;
/* Open pipes to stdin, stdout, stderr */
ret = pipe(in);
if (ret < 0)
goto err_in;
ret = pipe(out);
if (ret < 0)
goto err_out;
ret = pipe(err);
if (ret < 0)
goto err_err;
pid = fork();
if (pid > 0) { /* parent */
close(in[0]);
close(out[1]);
close(err[1]);
pipes[0] = in[1];
pipes[1] = out[0];
pipes[2] = err[0];
return pid;
} else if (pid == 0) { /* child */
close(in[1]);
close(out[0]);
close(err[0]);
dup2(in[0], 0);
dup2(out[1], 1);
dup2(err[1], 2);
/* just emulate what popen() does */
execl("/bin/sh", "sh", "-c", cmd, NULL);
exit(EXIT_FAILURE);
} else
goto err_fork;
return pid;
err_fork:
close(err[0]);
close(err[1]);
err_err:
close(out[0]);
close(out[1]);
err_out:
close(in[0]);
close(in[1]);
err_in:
return ret;
}
/**
* Close pipes previously opened with popen3.
*
* @param pid
* @param pipes
* @return
*/
int pclose3(pid_t pid, int *pipes)
{
int ret, status;
close(pipes[0]);
close(pipes[1]);
close(pipes[2]);
ret = waitpid(pid, &status, 0);
if (ret == 0)
return status;
else
return ret;
}
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