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1 | /* Subprocesses with pipes. |
2 | ||
3ea5f0ec | 3 | Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc. |
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4 | |
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 2, or (at your option) | |
8 | any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program; if not, write to the Free Software Foundation, | |
0fb669f9 | 17 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ |
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18 | |
19 | /* Written by Paul Eggert <eggert@twinsun.com> | |
20 | and Florian Krohm <florian@edamail.fishkill.ibm.com>. */ | |
21 | ||
22 | #if HAVE_CONFIG_H | |
23 | # include <config.h> | |
24 | #endif | |
25 | ||
b970803c | 26 | #include "subpipe.h" |
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27 | |
28 | #include <errno.h> | |
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29 | |
30 | #include <signal.h> | |
31 | #if ! defined SIGCHLD && defined SIGCLD | |
32 | # define SIGCHLD SIGCLD | |
33 | #endif | |
34 | ||
b970803c | 35 | #include <stdlib.h> |
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36 | |
37 | #if HAVE_UNISTD_H | |
38 | # include <unistd.h> | |
39 | #endif | |
40 | #ifndef STDIN_FILENO | |
41 | # define STDIN_FILENO 0 | |
42 | #endif | |
43 | #ifndef STDOUT_FILENO | |
44 | # define STDOUT_FILENO 1 | |
45 | #endif | |
46 | #if ! HAVE_DUP2 && ! defined dup2 | |
04098407 | 47 | # include <fcntl.h> |
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48 | # define dup2(f, t) (close (t), fcntl (f, F_DUPFD, t)) |
49 | #endif | |
50 | ||
51 | #if HAVE_SYS_WAIT_H | |
52 | # include <sys/wait.h> | |
53 | #endif | |
54 | #ifndef WEXITSTATUS | |
55 | # define WEXITSTATUS(stat_val) ((unsigned int) (stat_val) >> 8) | |
56 | #endif | |
57 | #ifndef WIFEXITED | |
58 | # define WIFEXITED(stat_val) (((stat_val) & 255) == 0) | |
59 | #endif | |
60 | ||
61 | #if HAVE_VFORK_H | |
62 | # include <vfork.h> | |
63 | #endif | |
64 | #if ! HAVE_WORKING_VFORK | |
65 | # define vfork fork | |
66 | #endif | |
67 | ||
68 | #include "error.h" | |
3ea5f0ec | 69 | #include "unistd-safer.h" |
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70 | |
71 | #include "gettext.h" | |
72 | #define _(Msgid) gettext (Msgid) | |
73 | ||
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74 | |
75 | /* Initialize this module. */ | |
76 | ||
77 | void | |
78 | init_subpipe (void) | |
79 | { | |
80 | #ifdef SIGCHLD | |
81 | /* System V fork+wait does not work if SIGCHLD is ignored. */ | |
82 | signal (SIGCHLD, SIG_DFL); | |
83 | #endif | |
84 | } | |
85 | ||
86 | ||
87 | /* Create a subprocess that is run as a filter. ARGV is the | |
88 | NULL-terminated argument vector for the subprocess. Store read and | |
89 | write file descriptors for communication with the subprocess into | |
90 | FD[0] and FD[1]: input meant for the process can be written into | |
91 | FD[0], and output from the process can be read from FD[1]. Return | |
92 | the subprocess id. | |
93 | ||
94 | To avoid deadlock, the invoker must not let incoming data pile up | |
95 | in FD[1] while writing data to FD[0]. */ | |
96 | ||
97 | pid_t | |
98 | create_subpipe (char const * const *argv, int fd[2]) | |
99 | { | |
100 | int pipe_fd[2]; | |
0fab8d7b | 101 | int child_fd[2]; |
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102 | pid_t pid; |
103 | ||
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104 | if (pipe (child_fd) != 0 |
105 | || (child_fd[0] = fd_safer (child_fd[0])) < 0 | |
106 | || (fd[0] = fd_safer (child_fd[1])) < 0 | |
3ea5f0ec | 107 | || pipe (pipe_fd) != 0 |
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108 | || (fd[1] = fd_safer (pipe_fd[0])) < 0 |
109 | || (child_fd[1] = fd_safer (pipe_fd[1])) < 0) | |
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110 | error (EXIT_FAILURE, errno, |
111 | "pipe"); | |
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112 | |
113 | pid = vfork (); | |
114 | if (pid < 0) | |
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115 | error (EXIT_FAILURE, errno, |
116 | "fork"); | |
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117 | |
118 | if (! pid) | |
119 | { | |
120 | /* Child. */ | |
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121 | close (fd[0]); |
122 | close (fd[1]); | |
123 | dup2 (child_fd[0], STDIN_FILENO); | |
124 | close (child_fd[0]); | |
125 | dup2 (child_fd[1], STDOUT_FILENO); | |
126 | close (child_fd[1]); | |
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127 | |
128 | /* The cast to (char **) rather than (char * const *) is needed | |
129 | for portability to older hosts with a nonstandard prototype | |
130 | for execvp. */ | |
131 | execvp (argv[0], (char **) argv); | |
3ea5f0ec | 132 | |
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133 | _exit (errno == ENOENT ? 127 : 126); |
134 | } | |
135 | ||
136 | /* Parent. */ | |
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137 | close (child_fd[0]); |
138 | close (child_fd[1]); | |
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139 | return pid; |
140 | } | |
141 | ||
142 | ||
143 | /* Wait for the subprocess to exit. */ | |
144 | ||
145 | void | |
146 | reap_subpipe (pid_t pid, char const *program) | |
147 | { | |
148 | #if HAVE_WAITPID || defined waitpid | |
149 | int wstatus; | |
150 | if (waitpid (pid, &wstatus, 0) < 0) | |
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151 | error (EXIT_FAILURE, errno, |
152 | "waitpid"); | |
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153 | else |
154 | { | |
155 | int status = WIFEXITED (wstatus) ? WEXITSTATUS (wstatus) : -1; | |
156 | if (status) | |
157 | error (EXIT_FAILURE, 0, | |
158 | _(status == 126 | |
159 | ? "subsidiary program `%s' could not be invoked" | |
160 | : status == 127 | |
161 | ? "subsidiary program `%s' not found" | |
162 | : status < 0 | |
163 | ? "subsidiary program `%s' failed" | |
164 | : "subsidiary program `%s' failed (exit status %d)"), | |
165 | program, status); | |
166 | } | |
167 | #endif | |
168 | } |