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Diffstat (limited to 'src/nohup.c')
| -rw-r--r-- | src/nohup.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/src/nohup.c b/src/nohup.c new file mode 100644 index 0000000..1f8e62b --- /dev/null +++ b/src/nohup.c @@ -0,0 +1,216 @@ +/* nohup -- run a command immune to hangups, with output to a non-tty + Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Jim Meyering */ + +#include <config.h> +#include <getopt.h> +#include <stdio.h> +#include <sys/types.h> +#include <signal.h> + +#include "system.h" + +#include "cloexec.h" +#include "error.h" +#include "filenamecat.h" +#include "fd-reopen.h" +#include "long-options.h" +#include "quote.h" +#include "unistd--.h" + +#define PROGRAM_NAME "nohup" + +#define AUTHORS "Jim Meyering" + +/* Exit statuses. */ +enum + { + /* `nohup' itself failed. */ + NOHUP_FAILURE = 127 + }; + +char *program_name; + +void +usage (int status) +{ + if (status != EXIT_SUCCESS) + fprintf (stderr, _("Try `%s --help' for more information.\n"), + program_name); + else + { + printf (_("\ +Usage: %s COMMAND [ARG]...\n\ + or: %s OPTION\n\ +"), + program_name, program_name); + + fputs (_("\ +Run COMMAND, ignoring hangup signals.\n\ +\n\ +"), stdout); + fputs (HELP_OPTION_DESCRIPTION, stdout); + fputs (VERSION_OPTION_DESCRIPTION, stdout); + printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME); + printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT); + } + exit (status); +} + +int +main (int argc, char **argv) +{ + int out_fd = STDOUT_FILENO; + int saved_stderr_fd = STDERR_FILENO; + bool ignoring_input; + bool redirecting_stdout; + bool stdout_is_closed; + bool redirecting_stderr; + + initialize_main (&argc, &argv); + program_name = argv[0]; + setlocale (LC_ALL, ""); + bindtextdomain (PACKAGE, LOCALEDIR); + textdomain (PACKAGE); + + initialize_exit_failure (NOHUP_FAILURE); + atexit (close_stdout); + + parse_long_options (argc, argv, PROGRAM_NAME, GNU_PACKAGE, VERSION, + usage, AUTHORS, (char const *) NULL); + if (getopt_long (argc, argv, "+", NULL, NULL) != -1) + usage (NOHUP_FAILURE); + + if (argc <= optind) + { + error (0, 0, _("missing operand")); + usage (NOHUP_FAILURE); + } + + ignoring_input = isatty (STDIN_FILENO); + redirecting_stdout = isatty (STDOUT_FILENO); + stdout_is_closed = (!redirecting_stdout && errno == EBADF); + redirecting_stderr = isatty (STDERR_FILENO); + + /* If standard input is a tty, replace it with /dev/null if possible. + Note that it is deliberately opened for *writing*, + to ensure any read evokes an error. */ + if (ignoring_input) + { + fd_reopen (STDIN_FILENO, "/dev/null", O_WRONLY, 0); + if (!redirecting_stdout && !redirecting_stderr) + error (0, 0, _("ignoring input")); + } + + /* If standard output is a tty, redirect it (appending) to a file. + First try nohup.out, then $HOME/nohup.out. If standard error is + a tty and standard output is closed, open nohup.out or + $HOME/nohup.out without redirecting anything. */ + if (redirecting_stdout || (redirecting_stderr && stdout_is_closed)) + { + char *in_home = NULL; + char const *file = "nohup.out"; + int flags = O_CREAT | O_WRONLY | O_APPEND; + mode_t mode = S_IRUSR | S_IWUSR; + mode_t umask_value = umask (~mode); + out_fd = (redirecting_stdout + ? fd_reopen (STDOUT_FILENO, file, flags, mode) + : open (file, flags, mode)); + + if (out_fd < 0) + { + int saved_errno = errno; + char const *home = getenv ("HOME"); + if (home) + { + in_home = file_name_concat (home, file, NULL); + out_fd = (redirecting_stdout + ? fd_reopen (STDOUT_FILENO, in_home, flags, mode) + : open (in_home, flags, mode)); + } + if (out_fd < 0) + { + int saved_errno2 = errno; + error (0, saved_errno, _("failed to open %s"), quote (file)); + if (in_home) + error (0, saved_errno2, _("failed to open %s"), + quote (in_home)); + exit (NOHUP_FAILURE); + } + file = in_home; + } + + umask (umask_value); + error (0, 0, + _(ignoring_input + ? "ignoring input and appending output to %s" + : "appending output to %s"), + quote (file)); + free (in_home); + } + + /* If standard error is a tty, redirect it. */ + if (redirecting_stderr) + { + /* Save a copy of stderr before redirecting, so we can use the original + if execve fails. It's no big deal if this dup fails. It might + not change anything, and at worst, it'll lead to suppression of + the post-failed-execve diagnostic. */ + saved_stderr_fd = dup (STDERR_FILENO); + + if (0 <= saved_stderr_fd + && set_cloexec_flag (saved_stderr_fd, true) != 0) + error (NOHUP_FAILURE, errno, + _("failed to set the copy of stderr to close on exec")); + + if (!redirecting_stdout) + error (0, 0, + _(ignoring_input + ? "ignoring input and redirecting stderr to stdout" + : "redirecting stderr to stdout")); + + if (dup2 (out_fd, STDERR_FILENO) < 0) + error (NOHUP_FAILURE, errno, _("failed to redirect standard error")); + + if (stdout_is_closed) + close (out_fd); + } + + signal (SIGHUP, SIG_IGN); + + { + int exit_status; + int saved_errno; + char **cmd = argv + optind; + + execvp (*cmd, cmd); + exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE); + saved_errno = errno; + + /* The execve failed. Output a diagnostic to stderr only if: + - stderr was initially redirected to a non-tty, or + - stderr was initially directed to a tty, and we + can dup2 it to point back to that same tty. + In other words, output the diagnostic if possible, but only if + it will go to the original stderr. */ + if (dup2 (saved_stderr_fd, STDERR_FILENO) == STDERR_FILENO) + error (0, saved_errno, _("cannot run command %s"), quote (*cmd)); + + exit (exit_status); + } +} |