sbase/nohup.c
FRIGN 6f207dac5f Don't return but _exit after failed exec*() and fork()
Quoting POSIX[0]:
"Care should be taken, also, to call _exit() rather than exit() if exec cannot be used, since
exit() flushes and closes standard I/O channels, thereby damaging the parent process' standard
I/O data structures. (Even with fork(), it is wrong to call exit(), since buffered data would
then be flushed twice.)"

[0]: http://pubs.opengroup.org/onlinepubs/009695399/functions/vfork.html
2015-03-09 01:12:59 +01:00

49 lines
891 B
C

/* See LICENSE file for copyright and license details. */
#include <sys/stat.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <unistd.h>
#include "util.h"
static void
usage(void)
{
eprintf("usage: %s cmd [arg ...]\n", argv0);
}
int
main(int argc, char *argv[])
{
int fd, savederrno;
ARGBEGIN {
default:
usage();
} ARGEND;
if (!argc)
usage();
if (signal(SIGHUP, SIG_IGN) == SIG_ERR)
enprintf(127, "signal HUP:");
if (isatty(STDOUT_FILENO)) {
if ((fd = open("nohup.out", O_APPEND | O_CREAT, S_IRUSR | S_IWUSR)) < 0)
enprintf(127, "open nohup.out:");
if (dup2(fd, STDOUT_FILENO) < 0)
enprintf(127, "dup2:");
close(fd);
}
if (isatty(STDERR_FILENO) && dup2(STDOUT_FILENO, STDERR_FILENO) < 0)
enprintf(127, "dup2:");
execvp(argv[0], argv);
savederrno = errno;
weprintf("execvp %s:", argv[0]);
_exit(126 + (savederrno == ENOENT));
}