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https://github.com/topjohnwu/ndk-busybox.git
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New version of nohup that's much smaller, less paranoid, consistent,
vaguely portable, and licensed GPLv2 "or later".
This commit is contained in:
Rob Landley
parent
4148afe049
commit
c020f5f518
@ -1,185 +1,55 @@
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/* vi: set sw=4 ts=4: */
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/* nohup -- run a command immune to hangups, with output to a non-tty
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Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
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Licensed under the GPL v2, see the file LICENSE in this tarball.
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/* vi:set ts=4: */
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/* nohup - invoke a utility immune to hangups.
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*
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* Busybox version based on nohup specification at
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* http://www.opengroup.org/onlinepubs/007904975/utilities/sed.html
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*
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* Copyright 2006 Rob Landley <rob@landley.net>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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/* Written by Jim Meyering */
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/* initial busybox port by Bernhard Fischer */
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#include <stdio_ext.h> /* __fpending */
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <signal.h>
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#include <errno.h>
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#include <unistd.h>
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#include "busybox.h"
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#define EXIT_CANNOT_INVOKE (126)
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#define NOHUP_FAILURE (127)
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#define EXIT_ENOENT NOHUP_FAILURE
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#if defined F_GETFD && defined F_SETFD
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static inline int set_cloexec_flag (int desc)
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int nohup_main(int argc, char *argv[])
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{
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int flags = fcntl (desc, F_GETFD, 0);
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if (0 <= flags) {
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if (flags == (flags |= FD_CLOEXEC) ||
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fcntl (desc, F_SETFD, flags) != -1) {
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return 0;
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}
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}
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return -1;
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}
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#else
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#define set_cloexec_flag(desc) (0)
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#endif
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int temp, nullfd;
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char *nohupout = "nohup.out", *home = NULL;
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static int fd_reopen (int desired_fd, char const *file, int flags)
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{
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int fd;
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if (argc<2) bb_show_usage();
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close (desired_fd);
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fd = open (file, flags | O_WRONLY, S_IRUSR | S_IWUSR);
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if (fd == desired_fd || fd < 0)
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return fd;
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else {
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int fd2 = fcntl (fd, F_DUPFD, desired_fd);
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int saved_errno = errno;
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close (fd);
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errno = saved_errno;
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return fd2;
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}
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}
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nullfd = bb_xopen(bb_dev_null, O_WRONLY|O_APPEND);
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// If stdin is a tty, detach from it.
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if (isatty(0)) dup2(nullfd, 0);
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/* Close standard output, exiting with status 'exit_failure' on failure.
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If a program writes *anything* to stdout, that program should close
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stdout and make sure that it succeeds before exiting. Otherwise,
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suppose that you go to the extreme of checking the return status
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of every function that does an explicit write to stdout. The last
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printf can succeed in writing to the internal stream buffer, and yet
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the fclose(stdout) could still fail (due e.g., to a disk full error)
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when it tries to write out that buffered data. Thus, you would be
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left with an incomplete output file and the offending program would
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exit successfully. Even calling fflush is not always sufficient,
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since some file systems (NFS and CODA) buffer written/flushed data
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until an actual close call.
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// Redirect stdout to nohup.out, either in "." or in "$HOME".
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Besides, it's wasteful to check the return value from every call
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that writes to stdout -- just let the internal stream state record
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the failure. That's what the ferror test is checking below.
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It's important to detect such failures and exit nonzero because many
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tools (most notably `make' and other build-management systems) depend
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on being able to detect failure in other tools via their exit status. */
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static void close_stdout (void)
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{
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int prev_fail = ferror (stdout);
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int none_pending = (0 == __fpending (stdout));
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int fclose_fail = fclose (stdout);
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if (prev_fail || fclose_fail) {
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/* If ferror returned zero, no data remains to be flushed, and we'd
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otherwise fail with EBADF due to a failed fclose, then assume that
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it's ok to ignore the fclose failure. That can happen when a
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program like cp is invoked like this `cp a b >&-' (i.e., with
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stdout closed) and doesn't generate any output (hence no previous
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error and nothing to be flushed). */
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if ((fclose_fail ? errno : 0) == EBADF && !prev_fail && none_pending)
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return;
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bb_perror_msg_and_die(bb_msg_write_error);
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}
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}
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int nohup_main (int argc, char **argv)
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{
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int saved_stderr_fd;
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if (argc < 2)
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bb_show_usage();
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bb_default_error_retval = NOHUP_FAILURE;
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atexit (close_stdout);
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/* If standard input is a tty, replace it with /dev/null.
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Note that it is deliberately opened for *writing*,
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to ensure any read evokes an error. */
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if (isatty (STDIN_FILENO))
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fd_reopen (STDIN_FILENO, bb_dev_null, 0);
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/* If standard output is a tty, redirect it (appending) to a file.
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First try nohup.out, then $HOME/nohup.out. */
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if (isatty (STDOUT_FILENO)) {
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char *in_home = NULL;
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char const *file = "nohup.out";
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int fd = fd_reopen (STDOUT_FILENO, file, O_CREAT | O_APPEND);
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if (fd < 0) {
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if ((in_home = getenv ("HOME")) != NULL) {
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in_home = concat_path_file(in_home, file);
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fd = fd_reopen (STDOUT_FILENO, in_home, O_CREAT | O_APPEND);
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if (isatty(1)) {
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close(1);
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if (open(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR) < 0) {
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home = getenv("HOME");
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if (home) {
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home = concat_path_file(home, nohupout);
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bb_xopen3(nohupout, O_CREAT|O_WRONLY|O_APPEND, S_IRUSR|S_IWUSR);
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}
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if (fd < 0) {
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bb_perror_msg("failed to open '%s'", file);
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if (in_home)
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bb_perror_msg("failed to open '%s'",in_home);
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return (NOHUP_FAILURE);
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}
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file = in_home;
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}
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} else dup2(nullfd, 1);
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umask (~(S_IRUSR | S_IWUSR));
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bb_error_msg("appending output to '%s'", file);
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if (ENABLE_FEATURE_CLEAN_UP)
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free (in_home);
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}
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// If we have a tty on strderr, announce filename and redirect to stdout.
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// Else redirect to /dev/null.
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/* If standard error is a tty, redirect it to stdout. */
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if (isatty (STDERR_FILENO)) {
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/* Save a copy of stderr before redirecting, so we can use the original
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if execve fails. It's no big deal if this dup fails. It might
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not change anything, and at worst, it'll lead to suppression of
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the post-failed-execve diagnostic. */
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saved_stderr_fd = dup (STDERR_FILENO);
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temp = isatty(2);
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if (temp) fdprintf(2,"Writing to %s\n", home ? home : nohupout);
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dup2(temp ? 1 : nullfd, 2);
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if (0 <= saved_stderr_fd && set_cloexec_flag (saved_stderr_fd) == -1)
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bb_perror_msg_and_die("failed to set the copy"
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"of stderr to close on exec");
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close(nullfd);
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if (dup2 (STDOUT_FILENO, STDERR_FILENO) < 0) {
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if (errno != EBADF)
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bb_perror_msg_and_die("failed to redirect standard error");
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close (STDERR_FILENO);
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}
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} else
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saved_stderr_fd = STDERR_FILENO;
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// Exec our new program.
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signal (SIGHUP, SIG_IGN);
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{
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char **cmd = argv + 1;
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execvp (*cmd, cmd);
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/* The execve failed. Output a diagnostic to stderr only if:
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- stderr was initially redirected to a non-tty, or
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- stderr was initially directed to a tty, and we
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can dup2 it to point back to that same tty.
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In other words, output the diagnostic if possible, but only if
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it will go to the original stderr. */
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if (dup2 (saved_stderr_fd, STDERR_FILENO) == STDERR_FILENO)
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bb_perror_msg("cannot run command '%s'",*cmd);
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return (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE);
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}
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execvp(argv[1],argv+1);
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if (ENABLE_FEATURE_CLEAN_UP) free(home);
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bb_error_msg_and_die("exec %s",argv[1]);
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}
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@ -105,4 +105,6 @@
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#define _(Text) Text
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#define N_(Text) (Text)
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#define fdprintf(...) dprintf(__VA_ARGS__)
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#endif /* platform.h */
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@ -283,21 +283,6 @@ int crond_main(int ac, char **av)
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bb_fflush_stdout_and_exit(EXIT_SUCCESS); /* not reached */
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}
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#if ENABLE_DEBUG_CROND_OPTION || ENABLE_FEATURE_CROND_CALL_SENDMAIL
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/*
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write to temp file..
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*/
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static void fdprintf(int fd, const char *ctl, ...)
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{
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va_list va;
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va_start(va, ctl);
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vdprintf(fd, ctl, va);
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va_end(va);
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}
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#endif
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static int ChangeUser(const char *user)
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{
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struct passwd *pas;
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