1 /* Subprocesses with pipes.
2
3 Copyright (C) 2005, 2006 Free Software Foundation, Inc.
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,
17 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
18
19 /* Written by Juan Manuel Guerrero <juan.guerrero@gmx.de>. */
20
21
22 #ifdef HAVE_CONFIG_H
23 # include <config.h>
24 #endif
25
26 #include "subpipe.h"
27
28 #include <errno.h>
29 #include <fcntl.h>
30 #include <sys/stat.h>
31 #include <process.h>
32 #include <signal.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <string.h>
36 #include <unistd.h>
37 #include "xalloc.h"
38
39
40 #ifndef STDIN_FILENO
41 # define STDIN_FILENO 0
42 #endif
43 #ifndef STDOUT_FILENO
44 # define STDOUT_FILENO 1
45 #endif
46
47
48 #include "error.h"
49
50 #include "gettext.h"
51 #define _(Msgid) gettext (Msgid)
52
53
54 /* Initialize this module. */
55
56
57 static int old_stdin;
58 static int old_stdout;
59 static char **arguments;
60 static char tmp_file_name[2][L_tmpnam];
61
62 #define remove_tmp_file(fd, name) \
63 do { \
64 close ((fd)); \
65 if (unlink ((name))) \
66 error (EXIT_FAILURE, 0, _("removing of `%s' failed"), (name)); \
67 } while (0)
68
69
70 void
init_subpipe(void)71 init_subpipe(void)
72 {
73 int fd;
74
75 strcpy(tmp_file_name[0], "/dev/env/TMPDIR/bnXXXXXX");
76 fd = mkstemp(tmp_file_name[0]);
77 if (fd < 0)
78 error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
79 close (fd);
80
81 strcpy(tmp_file_name[1], "/dev/env/TMPDIR/bnXXXXXX");
82 fd = mkstemp(tmp_file_name[1]);
83 if (fd < 0)
84 error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
85 close (fd);
86 }
87
88
89 /* Create a subprocess that is run as a filter. ARGV is the
90 NULL-terminated argument vector for the subprocess. Store read and
91 write file descriptors for communication with the subprocess into
92 FD[0] and FD[1]: input meant for the process can be written into
93 FD[0], and output from the process can be read from FD[1]. Return
94 the subprocess id.
95
96 Because DOS has neither fork nor pipe functionality to run the subprocess
97 as a filter, the filter is reproduced using temporary files. First bison's
98 stdout is redirected to a temporary file. After bison has produced all of
99 is output, this file is closed and connected to m4's stdin. All m4's output
100 is redirected from m4's stdout to a second temporary file and reopened as
101 bison's stdin. */
102
103 pid_t
create_subpipe(char const * const * argv,int fd[2])104 create_subpipe(char const *const *argv, int fd[2])
105 {
106 int argc;
107 int from_in_fd; /* pipe from bison to m4. */
108 pid_t pid;
109
110
111 pid = getpid();
112
113 /*
114 * Save original stdin and stdout
115 * for later restauration.
116 */
117 old_stdin = dup(STDIN_FILENO);
118 if (old_stdin < 0)
119 error(EXIT_FAILURE, 0, _("saving stdin failed"));
120
121 old_stdout = dup(STDOUT_FILENO);
122 if (old_stdout < 0)
123 error(EXIT_FAILURE, 0, _("saving stdout failed"));
124
125 /*
126 * Save argv for later use.
127 */
128 for (argc = 0; argv[argc]; argc++)
129 ;
130 argc++;
131 arguments = xmalloc(argc * sizeof(arguments[0]));
132 for (argc = 0; argv[argc]; argc++)
133 {
134 arguments[argc] = xmalloc((strlen(argv[argc]) + 1) * sizeof(arguments[0][0]));
135 strcpy(arguments[argc], argv[argc]);
136 }
137 arguments[argc] = NULL;
138
139 /*
140 * All bison's output will be gathered in this temporary file
141 * and will be redirected to m4's stdin.
142 */
143 from_in_fd = open(tmp_file_name[0], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);
144 if (from_in_fd < 0)
145 error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
146 if (dup2(from_in_fd, STDOUT_FILENO) < 0)
147 {
148 remove_tmp_file(from_in_fd, tmp_file_name[0]);
149 error(EXIT_FAILURE, 0, _("redirecting bison's stdout to the temporary file failed"));
150 }
151 close(from_in_fd);
152
153
154 fd[0] = STDOUT_FILENO;
155 return pid;
156 }
157
158
159 /* A signal handler that just records that a signal has happened. */
160 static int child_interrupted;
161
162 static void
signal_catcher(int signo)163 signal_catcher(int signo)
164 {
165 child_interrupted++;
166 }
167
168
169 void
end_of_output_subpipe(pid_t pid,int fd[2])170 end_of_output_subpipe(pid_t pid, int fd[2])
171 {
172 char *program;
173 int from_out_fd = open(tmp_file_name[0], O_RDONLY, S_IRUSR); /* pipe from bison to m4. */
174 int to_in_fd = open(tmp_file_name[1], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR); /* pipe from m4 to bison. */
175 int status;
176 void (*previous_handler)(int);
177
178
179 program = strrchr(arguments[0], '/');
180 if (program)
181 program++;
182 else
183 program = arguments[0];
184
185 /*
186 * Redirect bison's output to m4's stdin.
187 */
188 if (from_out_fd < 0)
189 error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
190 if (dup2(from_out_fd, STDIN_FILENO) < 0)
191 {
192 remove_tmp_file(from_out_fd, tmp_file_name[0]);
193 error(EXIT_FAILURE, 0, _("redirecting m4's stdin from the temporary file failed"));
194 }
195 close(from_out_fd);
196
197 /*
198 * All m4's output will be gathered in this temporary file
199 * and will be redirected to bison's stdin.
200 */
201 if (to_in_fd < 0)
202 {
203 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
204 error(EXIT_FAILURE, 0, _("opening of a temporary file failed"));
205 }
206 if (dup2(to_in_fd, STDOUT_FILENO) < 0)
207 {
208 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
209 remove_tmp_file(to_in_fd, tmp_file_name[1]);
210 error(EXIT_FAILURE, 0, _("redirecting m4's stdout to a temporary file failed"));
211 }
212 close(to_in_fd);
213
214 /*
215 * Run m4.
216 */
217 child_interrupted = 0;
218 errno = 0;
219 previous_handler = signal(SIGINT, signal_catcher);
220 status = spawnvp(P_WAIT, program, arguments);
221 signal(SIGINT, previous_handler);
222 if (child_interrupted)
223 {
224 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
225 remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
226 error(EXIT_FAILURE, 0, _("subsidiary program `%s' interrupted"), program);
227 }
228 if (status)
229 {
230 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
231 remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
232 error(EXIT_FAILURE, 0, _(errno == ENOENT
233 ? "subsidiary program `%s' not found"
234 : status < 1
235 ? "subsidiary program `%s' failed"
236 : "subsidiary program `%s' failed (status=%i, errno=%i)"), program, status, errno);
237 }
238
239
240 /*
241 * Redirect m4's output to bison's stdin.
242 */
243 if (dup2(old_stdout, STDOUT_FILENO) < 0)
244 error(EXIT_FAILURE, 0, "restore of bison's stdout failed");
245 close(old_stdout);
246 to_in_fd = open(tmp_file_name[1], O_RDONLY, S_IRUSR); /* pipe from m4 to bison. */
247 if (to_in_fd < 0)
248 {
249 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
250 error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
251 }
252 if (dup2(to_in_fd, STDIN_FILENO) < 0)
253 {
254 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
255 remove_tmp_file(to_in_fd, tmp_file_name[1]);
256 error(EXIT_FAILURE, -1, "dup2");
257 error(EXIT_FAILURE, 0, _("redirecting bison's stdin from the temporary file failed"));
258 }
259 close(to_in_fd);
260
261
262 fd[1] = STDIN_FILENO;
263 }
264
265
266 /* Free resources, unlink temporary files and restore stdin and stdout. */
267
268 void
reap_subpipe(pid_t pid,char const * program)269 reap_subpipe(pid_t pid, char const *program)
270 {
271 int argc;
272
273 for (argc = 0; arguments[argc]; argc++)
274 free(arguments[argc]);
275 free(arguments);
276
277 if (unlink(tmp_file_name[0]))
278 error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[0]);
279 if (unlink(tmp_file_name[1]))
280 error(EXIT_FAILURE, 0, _("removing of `%s' failed"), tmp_file_name[1]);
281
282 if (dup2(old_stdin, STDIN_FILENO) < 0)
283 error(EXIT_FAILURE, 0, "restore of bison's stdin failed");
284 close(old_stdin);
285 }
286