busybox/coreutils/nohup.c

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/* vi:set ts=4: */
/* nohup - invoke a utility immune to hangups.
*
* Busybox version based on nohup specification at
* http://www.opengroup.org/onlinepubs/007904975/utilities/nohup.html
*
* Copyright 2006 Rob Landley <rob@landley.net>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
#include <fcntl.h>
#include <signal.h>
#include <unistd.h>
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#include "busybox.h"
int nohup_main(int argc, char *argv[])
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{
int temp, nullfd;
char *nohupout = "nohup.out", *home = NULL;
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// I have no idea why the standard cares about this.
bb_default_error_retval = 127;
if (argc<2) bb_show_usage();
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nullfd = bb_xopen(bb_dev_null, O_WRONLY|O_APPEND);
// If stdin is a tty, detach from it.
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if (isatty(0)) dup2(nullfd, 0);
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// Redirect stdout to nohup.out, either in "." or in "$HOME".
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if (isatty(1)) {
close(1);
if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
home = getenv("HOME");
if (home) {
home = concat_path_file(home, nohupout);
bb_xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
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}
}
} else dup2(nullfd, 1);
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// If we have a tty on strderr, announce filename and redirect to stdout.
// Else redirect to /dev/null.
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temp = isatty(2);
if (temp) fdprintf(2,"Writing to %s\n", home ? home : nohupout);
dup2(temp ? 1 : nullfd, 2);
close(nullfd);
signal (SIGHUP, SIG_IGN);
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// Exec our new program.
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execvp(argv[1],argv+1);
if (ENABLE_FEATURE_CLEAN_UP) free(home);
bb_error_msg_and_die("exec %s",argv[1]);
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}