1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
|
/* nohup -- run a command immune to hangups, with output to a non-tty
Copyright (C) 2003-2017 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 3 of the License, 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, see <http://www.gnu.org/licenses/>. */
/* 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 "unistd--.h"
#define PROGRAM_NAME "nohup"
#define AUTHORS proper_name ("Jim Meyering")
/* Exit statuses. */
enum
{
/* 'nohup' itself failed. */
POSIX_NOHUP_FAILURE = 127
};
void
usage (int status)
{
if (status != EXIT_SUCCESS)
emit_try_help ();
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 (_("\n\
If standard input is a terminal, redirect it from an unreadable file.\n\
If standard output is a terminal, append output to 'nohup.out' if possible,\n\
'$HOME/nohup.out' otherwise.\n\
If standard error is a terminal, redirect it to standard output.\n\
To save output to FILE, use '%s COMMAND > FILE'.\n"),
program_name);
printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
emit_ancillary_info (PROGRAM_NAME);
}
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;
int exit_internal_failure;
initialize_main (&argc, &argv);
set_program_name (argv[0]);
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
/* POSIX 2008 requires that internal failure give status 127; unlike
for env, exec, nice, time, and xargs where it requires internal
failure give something in the range 1-125. For consistency with
other tools, fail with EXIT_CANCELED unless POSIXLY_CORRECT. */
exit_internal_failure = (getenv ("POSIXLY_CORRECT")
? POSIX_NOHUP_FAILURE : EXIT_CANCELED);
initialize_exit_failure (exit_internal_failure);
atexit (close_stdout);
parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, Version,
usage, AUTHORS, (char const *) NULL);
if (getopt_long (argc, argv, "+", NULL, NULL) != -1)
usage (exit_internal_failure);
if (argc <= optind)
{
error (0, 0, _("missing operand"));
usage (exit_internal_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)
{
if (fd_reopen (STDIN_FILENO, "/dev/null", O_WRONLY, 0) < 0)
error (exit_internal_failure, errno,
_("failed to render standard input unusable"));
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"), quoteaf (file));
if (in_home)
error (0, saved_errno2, _("failed to open %s"),
quoteaf (in_home));
return exit_internal_failure;
}
file = in_home;
}
umask (umask_value);
error (0, 0,
_(ignoring_input
? N_("ignoring input and appending output to %s")
: N_("appending output to %s")),
quoteaf (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 (exit_internal_failure, errno,
_("failed to set the copy of stderr to close on exec"));
if (!redirecting_stdout)
error (0, 0,
_(ignoring_input
? N_("ignoring input and redirecting stderr to stdout")
: N_("redirecting stderr to stdout")));
if (dup2 (out_fd, STDERR_FILENO) < 0)
error (exit_internal_failure, errno,
_("failed to redirect standard error"));
if (stdout_is_closed)
close (out_fd);
}
/* error() flushes stderr, but does not check for write failure.
Normally, we would catch this via our atexit() hook of
close_stdout, but execvp() gets in the way. If stderr
encountered a write failure, there is no need to try calling
error() again, particularly since we may have just changed the
underlying fd out from under stderr. */
if (ferror (stderr))
return exit_internal_failure;
signal (SIGHUP, SIG_IGN);
char **cmd = argv + optind;
execvp (*cmd, cmd);
int exit_status = errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE;
int 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, _("failed to run command %s"), quoteaf (*cmd));
return exit_status;
}
|
