busybox/coreutils/nohup.c
Denys Vlasenko 5c527dc57e make 17 state-changing execing applets (ex: "nice PROG ARGS") noexec
The applets with "<applet> [opts] PROG ARGS" API very quickly exec
another program, noexec is okay for them:

 chpst/envdir/envuidgid/softlimit/setuidgid
 chroot
 chrt
 ionice
 nice
 nohup
 setarch/linux32/linux64
 taskset
 cttyhack

"reset" and "sulogin" applets don't have this form, but also exec
another program at once, thus made noexec too.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-04 19:55:01 +02:00

98 lines
2.6 KiB
C

/* vi: set sw=4 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>
* Copyright 2006 Bernhard Reutner-Fischer
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config NOHUP
//config: bool "nohup (2 kb)"
//config: default y
//config: help
//config: run a command immune to hangups, with output to a non-tty.
//applet:IF_NOHUP(APPLET_NOEXEC(nohup, nohup, BB_DIR_USR_BIN, BB_SUID_DROP, nohup))
//kbuild:lib-$(CONFIG_NOHUP) += nohup.o
//usage:#define nohup_trivial_usage
//usage: "PROG ARGS"
//usage:#define nohup_full_usage "\n\n"
//usage: "Run PROG immune to hangups, with output to a non-tty"
//usage:
//usage:#define nohup_example_usage
//usage: "$ nohup make &"
#include "libbb.h"
/* Compat info: nohup (GNU coreutils 6.8) does this:
# nohup true
nohup: ignoring input and appending output to 'nohup.out'
# nohup true 1>/dev/null
nohup: ignoring input and redirecting stderr to stdout
# nohup true 2>zz
# cat zz
nohup: ignoring input and appending output to 'nohup.out'
# nohup true 2>zz 1>/dev/null
# cat zz
nohup: ignoring input
# nohup true </dev/null 1>/dev/null
nohup: redirecting stderr to stdout
# nohup true </dev/null 2>zz 1>/dev/null
# cat zz
(nothing)
#
*/
int nohup_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nohup_main(int argc UNUSED_PARAM, char **argv)
{
const char *nohupout;
char *home;
xfunc_error_retval = 127;
if (!argv[1]) {
bb_show_usage();
}
/* If stdin is a tty, detach from it. */
if (isatty(STDIN_FILENO)) {
/* bb_error_msg("ignoring input"); */
close(STDIN_FILENO);
xopen(bb_dev_null, O_RDONLY); /* will be fd 0 (STDIN_FILENO) */
}
nohupout = "nohup.out";
/* Redirect stdout to nohup.out, either in "." or in "$HOME". */
if (isatty(STDOUT_FILENO)) {
close(STDOUT_FILENO);
if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
home = getenv("HOME");
if (home) {
nohupout = concat_path_file(home, nohupout);
xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
} else {
xopen(bb_dev_null, O_RDONLY); /* will be fd 1 */
}
}
bb_error_msg("appending output to %s", nohupout);
}
/* If we have a tty on stderr, redirect to stdout. */
if (isatty(STDERR_FILENO)) {
/* if (stdout_wasnt_a_tty)
bb_error_msg("redirecting stderr to stdout"); */
dup2(STDOUT_FILENO, STDERR_FILENO);
}
signal(SIGHUP, SIG_IGN);
argv++;
BB_EXECVP_or_die(argv);
}