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
|
/* Creation of subprocesses, communicating via pipes.
Copyright (C) 2001 Free Software Foundation, Inc.
Written by Bruno Haible <haible@clisp.cons.org>, 2001.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
/* Specification. */
#include "pipe.h"
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#ifdef HAVE_POSIX_SPAWN
# include <spawn.h>
#else
# ifdef HAVE_VFORK_H
# include <vfork.h>
# endif
#endif
#include "error.h"
#include "exit.h"
#include "gettext.h"
#ifndef STDIN_FILENO
# define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
# define STDOUT_FILENO 1
#endif
#define _(str) gettext (str)
/* Prototypes for local functions. Needed to ensure compiler checking of
function argument counts despite of K&R C function definition syntax. */
#ifdef EINTR
static inline int nonintr_close PARAMS ((int fd));
#endif
#ifdef EINTR
/* EINTR handling for close().
These functions can return -1/EINTR even though we don't have any
signal handlers set up, namely when we get interrupted via SIGSTOP. */
static inline int
nonintr_close (fd)
int fd;
{
int retval;
do
retval = close (fd);
while (retval < 0 && errno == EINTR);
return retval;
}
#define close nonintr_close
#endif
/* Open a bidirectional pipe.
*
* write system read
* parent -> fd[1] -> STDIN_FILENO -> child
* parent <- fd[0] <- STDOUT_FILENO <- child
* read system write
*
*/
pid_t
create_pipe_bidi (progname, prog_path, prog_argv, null_stderr, exit_on_error, fd)
const char *progname;
const char *prog_path;
char **prog_argv;
bool null_stderr;
bool exit_on_error;
int fd[2];
{
int ifd[2];
int ofd[2];
#if HAVE_POSIX_SPAWN
posix_spawn_file_actions_t actions;
bool actions_allocated;
int err;
pid_t child;
#else
int child;
#endif
if (pipe (ifd) < 0)
error (EXIT_FAILURE, errno, _("cannot create pipe"));
if (pipe (ofd) < 0)
error (EXIT_FAILURE, errno, _("cannot create pipe"));
/* Data flow diagram:
*
* write system read
* parent -> ofd[1] -> ofd[0] -> child
* parent <- ifd[0] <- ifd[1] <- child
* read system write
*
*/
#if HAVE_POSIX_SPAWN
actions_allocated = false;
if ((err = posix_spawn_file_actions_init (&actions)) != 0
|| (actions_allocated = true,
(err = posix_spawn_file_actions_adddup2 (&actions,
ofd[0], STDIN_FILENO)) != 0
|| (err = posix_spawn_file_actions_adddup2 (&actions,
ifd[1], STDOUT_FILENO))
!= 0
|| (err = posix_spawn_file_actions_addclose (&actions, ofd[0])) != 0
|| (err = posix_spawn_file_actions_addclose (&actions, ifd[1])) != 0
|| (err = posix_spawn_file_actions_addclose (&actions, ofd[1])) != 0
|| (err = posix_spawn_file_actions_addclose (&actions, ifd[0])) != 0
|| (null_stderr
&& (err = posix_spawn_file_actions_addopen (&actions,
STDERR_FILENO,
"/dev/null", O_RDWR,
0))
!= 0)
|| (err = posix_spawnp (&child, prog_path, &actions, NULL, prog_argv,
environ)) != 0))
{
if (actions_allocated)
posix_spawn_file_actions_destroy (&actions);
if (exit_on_error)
error (EXIT_FAILURE, err, _("%s subprocess failed"), progname);
else
{
close (ifd[0]);
close (ifd[1]);
close (ofd[0]);
close (ofd[1]);
return -1;
}
}
posix_spawn_file_actions_destroy (&actions);
#else
/* Use vfork() instead of fork() for efficiency. */
if ((child = vfork ()) == 0)
{
/* Child process code. */
int nulloutfd;
if (dup2 (ofd[0], STDIN_FILENO) >= 0
&& dup2 (ifd[1], STDOUT_FILENO) >= 0
&& close (ofd[0]) >= 0
&& close (ifd[1]) >= 0
&& close (ofd[1]) >= 0
&& close (ifd[0]) >= 0
&& (!null_stderr
|| ((nulloutfd = open ("/dev/null", O_RDWR, 0)) >= 0
&& (nulloutfd == STDERR_FILENO
|| (dup2 (nulloutfd, STDERR_FILENO) >= 0
&& close (nulloutfd) >= 0)))))
execvp (prog_path, prog_argv);
_exit (127);
}
if (child == -1)
{
if (exit_on_error)
error (EXIT_FAILURE, errno, _("%s subprocess failed"), progname);
else
{
close (ifd[0]);
close (ifd[1]);
close (ofd[0]);
close (ofd[1]);
return -1;
}
}
#endif
close (ofd[0]);
close (ifd[1]);
fd[0] = ifd[0];
fd[1] = ofd[1];
return child;
}
|
