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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#if !defined (__SVR4) || !defined (__sun)
#define _XOPEN_SOURCE 600
#define _BSD_SOURCE
#include <termios.h>
#else
#include <stropts.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/termios.h>
static pid_t pty_fork();
#ifdef __CYGWIN__
//added for compatibility with cygwin 1.5
#define WCONTINUED 0
#endif
int main(int argc, char* argv[]) {
pid_t pid, w;
int status;
char *pty = NULL;
int c;
int err_flag = 0;
int close_term = 0;
while (pty == NULL && (c = getopt(argc, argv, "qp:")) != EOF) {
switch (c) {
case 'p':
pty = optarg;
break;
case 'q':
close_term = 1;
break;
default:
err_flag++;
break;
}
}
if (err_flag || (optind >= argc)) {
printf("ERROR: Usage: process_start [-q] -p pty command [arg ...]\n");
exit(1);
}
if (!pty) {
printf("ERROR: -p required\n");
exit(-1);
}
pid = fork();
if (pid == -1) {
printf("ERROR: fork failed\n");
exit(1);
}
int pty_fd = open(pty, O_RDWR);
if (pid == 0) {
int saved_stdout = -1;
int saved_errno;
// Remember stdout so that if exec fails we can still output.
// Mark the remembered fd as close-on-exec so that it's not
// inherited past the exec.
saved_stdout = fcntl(1, F_DUPFD, 3);
fcntl(saved_stdout, F_SETFD, FD_CLOEXEC);
// If we don't do this ^C/^Z etc won't work.
// We used to use 'setpgrp()' but it was only effective on Solaris
// and not Linux. 'setsid()' seems to work for both.
if (setsid() == -1) {
printf("ERROR setsid() failed -- %s\n", strerror(errno));
exit(-1);
}
// Ensure SIGINT isn't being ignored
struct sigaction act;
sigaction(SIGINT, NULL, &act);
act.sa_handler = SIG_DFL;
sigaction(SIGINT, &act, NULL);
if (pty_fd == -1) {
printf("ERROR cannot open pty \"%s\" -- %s\n",
pty, strerror(errno));
exit(-1);
}
// setsid() leaves us w/o a controlling terminal.
// On Linux and Solaris the first open makes whatever we opened
// our controlling terminal.
// On BSD/Mac we need to explicitly assign a controlling terminal
// using TIOCSCTTY. It does no harm on Linux either.
#if defined(TIOCSCTTY)
if (ioctl(pty_fd, TIOCSCTTY, 0) == -1) {
printf("ERROR ioctl(TIOCSCTTY) failed on \"%s\" -- %s\n",
pty, strerror(errno));
exit(-1);
}
#endif
// redirect stdio through the pty
dup2(pty_fd, 0);
dup2(pty_fd, 1);
dup2(pty_fd, 2);
close(pty_fd);
if (execvp(argv[optind], &argv[optind]) == -1) {
printf("ERROR: %s\n", argv[optind]);
exit(1);
}
saved_errno = errno; // save errno around close() and dup()
if (saved_stdout != -1) {
// restore stdout so the below printf works
close(1);
dup(saved_stdout);
}
printf("ERROR exec failed -- %s\n", strerror(saved_errno));
}
printf("%d\n", pid);
// Flush out the PID message before we take away stdout
fflush(stdout);
w = waitpid(pid, &status, WUNTRACED | WCONTINUED);
if (close_term) {
#if defined _XOPEN_STREAMS && _XOPEN_STREAMS != -1
tcsendbreak(pty_fd, 0);
#endif
}
if (w != -1 && WIFEXITED(status)) {
exit(WEXITSTATUS(status));
}
exit(EXIT_FAILURE);
}
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