141 lines
3.6 KiB
C
141 lines
3.6 KiB
C
/*
|
|
* Copyright (c) 2009, Erik van der Kouwe
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright notice,
|
|
* this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright notice,
|
|
* this list of conditions and the following disclaimer in the documentation
|
|
* and/or other materials provided with the distribution.
|
|
* 3. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
|
|
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
|
|
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
|
|
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
|
|
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
|
|
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
|
|
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
|
|
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
* Functionality implemented according to this specification:
|
|
* http://www.opengroup.org/onlinepubs/000095399/utilities/nohup.html
|
|
*/
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <limits.h>
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <sys/stat.h>
|
|
#include <unistd.h>
|
|
|
|
#define NOHUP_OUT_FILENAME "nohup.out"
|
|
|
|
static void print_usage(const char *argv0)
|
|
{
|
|
printf("Usage: %s command [arg...]\n", argv0);
|
|
}
|
|
|
|
static int redirect_tty(void)
|
|
{
|
|
int fd;
|
|
char buffer[PATH_MAX + 1], *home;
|
|
|
|
/* redirect stdout to a file if needed */
|
|
if (isatty(STDOUT_FILENO))
|
|
{
|
|
/* first try: current directory */
|
|
fd = open(NOHUP_OUT_FILENAME, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
|
|
if (fd < 0)
|
|
{
|
|
/* alternative: home directory */
|
|
home = getenv("HOME");
|
|
if (home)
|
|
{
|
|
snprintf(buffer, sizeof(buffer), "%s/%s", home, NOHUP_OUT_FILENAME);
|
|
buffer[sizeof(buffer) - 1] = 0;
|
|
fd = open(buffer, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
|
|
}
|
|
}
|
|
|
|
if (fd < 0)
|
|
{
|
|
perror("cannot create " NOHUP_OUT_FILENAME " and $HOME/" NOHUP_OUT_FILENAME);
|
|
return -1;
|
|
}
|
|
|
|
/* move the fd to stdout */
|
|
if (dup2(fd, STDOUT_FILENO) < 0 || close(fd) < 0)
|
|
{
|
|
perror("cannot redirect stdout");
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* redirect stderr to stdout if needed */
|
|
if (isatty(STDERR_FILENO))
|
|
{
|
|
if (dup2(STDOUT_FILENO, STDERR_FILENO) < 0)
|
|
{
|
|
perror("cannot redirect stderr");
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
struct sigaction sa;
|
|
|
|
/* check parameters */
|
|
if (argc < 2)
|
|
{
|
|
print_usage(argv[0]);
|
|
return 127;
|
|
}
|
|
|
|
/* ignore SIGHUP */
|
|
sa.sa_handler = SIG_IGN;
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags = 0;
|
|
if (sigaction(SIGHUP, &sa, NULL) < 0)
|
|
{
|
|
perror("cannot ignore SIGHUP");
|
|
return 127;
|
|
}
|
|
|
|
/* redirect TTY input and output */
|
|
if (redirect_tty() < 0)
|
|
return 127;
|
|
|
|
/* run the command */
|
|
execvp(argv[1], argv + 1);
|
|
perror("cannot execute");
|
|
|
|
/* exit code depends on whether the utility was found */
|
|
switch (errno)
|
|
{
|
|
case ELOOP:
|
|
case ENAMETOOLONG:
|
|
case ENOENT:
|
|
case ENOTDIR:
|
|
/* utility not found */
|
|
return 127;
|
|
|
|
default:
|
|
/* exec failed for other reason */
|
|
return 126;
|
|
}
|
|
}
|