1 /* Subprocesses with pipes.
2
3 Copyright (C) 2005-2012 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 3 of the License, or
8 (at your option) 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, see <http://www.gnu.org/licenses/>. */
17
18 /* Written by Juan Manuel Guerrero <juan.guerrero@gmx.de>. */
19
20
21 #include <config.h>
22
23 #include "subpipe.h"
24
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <sys/stat.h>
28 #include <process.h>
29 #include <signal.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <unistd.h>
34 #include "xalloc.h"
35
36
37 #ifndef STDIN_FILENO
38 # define STDIN_FILENO 0
39 #endif
40 #ifndef STDOUT_FILENO
41 # define STDOUT_FILENO 1
42 #endif
43
44
45 #include "error.h"
46
47 #include "gettext.h"
48 #define _(Msgid) gettext (Msgid)
49
50
51 /* Initialize this module. */
52
53
54 static int old_stdin;
55 static int old_stdout;
56 static char **arguments;
57 static char tmp_file_name[2][L_tmpnam];
58
59 #define remove_tmp_file(fd, name) \
60 do { \
61 close ((fd)); \
62 if (unlink ((name))) \
63 error (EXIT_FAILURE, 0, _("removing of '%s' failed"), (name)); \
64 } while (0)
65
66
67 void
init_subpipe(void)68 init_subpipe(void)
69 {
70 char *tmpdir;
71 int fd;
72
73 tmpdir = getenv("TMPDIR");
74 if (tmpdir == NULL)
75 tmpdir = getenv("TMP");
76 if (tmpdir == NULL)
77 tmpdir = getenv("TEMP");
78 if (access(tmpdir, D_OK))
79 tmpdir = ".";
80
81 strcpy(tmp_file_name[0], tmpdir);
82 strcat(tmp_file_name[0], "/bnXXXXXX");
83 fd = mkstemp(tmp_file_name[0]);
84 if (fd < 0)
85 error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
86 close (fd);
87
88 strcpy(tmp_file_name[1], tmpdir);
89 strcat(tmp_file_name[1], "/bnXXXXXX");
90 fd = mkstemp(tmp_file_name[1]);
91 if (fd < 0)
92 error(EXIT_FAILURE, 0, _("creation of a temporary file failed"));
93 close (fd);
94 }
95
96
97 /* Create a subprocess that is run as a filter. ARGV is the
98 NULL-terminated argument vector for the subprocess. Store read and
99 write file descriptors for communication with the subprocess into
100 FD[0] and FD[1]: input meant for the process can be written into
101 FD[0], and output from the process can be read from FD[1]. Return
102 the subprocess id.
103
104 Because DOS has neither fork nor pipe functionality to run the subprocess
105 as a filter, the filter is reproduced using temporary files. First bison's
106 stdout is redirected to a temporary file. After bison has produced all of
107 is output, this file is closed and connected to m4's stdin. All m4's output
108 is redirected from m4's stdout to a second temporary file and reopened as
109 bison's stdin. */
110
111 pid_t
create_subpipe(char const * const * argv,int fd[2])112 create_subpipe(char const *const *argv, int fd[2])
113 {
114 int argc;
115 int from_in_fd; /* pipe from bison to m4. */
116 pid_t pid;
117
118
119 pid = getpid();
120
121 /*
122 * Save original stdin and stdout
123 * for later restauration.
124 */
125 old_stdin = dup(STDIN_FILENO);
126 if (old_stdin < 0)
127 error(EXIT_FAILURE, 0, _("saving stdin failed"));
128
129 old_stdout = dup(STDOUT_FILENO);
130 if (old_stdout < 0)
131 error(EXIT_FAILURE, 0, _("saving stdout failed"));
132
133 /*
134 * Save argv for later use.
135 */
136 for (argc = 0; argv[argc]; argc++)
137 ;
138 argc++;
139 arguments = xmalloc(argc * sizeof(arguments[0]));
140 for (argc = 0; argv[argc]; argc++)
141 {
142 arguments[argc] = xmalloc((strlen(argv[argc]) + 1) * sizeof(arguments[0][0]));
143 strcpy(arguments[argc], argv[argc]);
144 }
145 arguments[argc] = NULL;
146
147 /*
148 * All bison's output will be gathered in this temporary file
149 * and will be redirected to m4's stdin.
150 */
151 from_in_fd = open(tmp_file_name[0], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR);
152 if (from_in_fd < 0)
153 error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
154 if (dup2(from_in_fd, STDOUT_FILENO) < 0)
155 {
156 remove_tmp_file(from_in_fd, tmp_file_name[0]);
157 error(EXIT_FAILURE, 0, _("redirecting bison's stdout to the temporary file failed"));
158 }
159 close(from_in_fd);
160
161
162 fd[0] = STDOUT_FILENO;
163 return pid;
164 }
165
166
167 /* A signal handler that just records that a signal has happened. */
168 static int child_interrupted;
169
170 static void
signal_catcher(int signo)171 signal_catcher(int signo)
172 {
173 child_interrupted++;
174 }
175
176
177 void
end_of_output_subpipe(pid_t pid,int fd[2])178 end_of_output_subpipe(pid_t pid, int fd[2])
179 {
180 char *program;
181 int from_out_fd = open(tmp_file_name[0], O_RDONLY, S_IRUSR); /* pipe from bison to m4. */
182 int to_in_fd = open(tmp_file_name[1], O_WRONLY | O_CREAT | O_TRUNC, S_IWUSR); /* pipe from m4 to bison. */
183 int status;
184 void (*previous_handler)(int);
185
186
187 program = strrchr(arguments[0], '/');
188 if (program)
189 program++;
190 else
191 program = arguments[0];
192
193 /*
194 * Redirect bison's output to m4's stdin.
195 */
196 if (from_out_fd < 0)
197 error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
198 if (dup2(from_out_fd, STDIN_FILENO) < 0)
199 {
200 remove_tmp_file(from_out_fd, tmp_file_name[0]);
201 error(EXIT_FAILURE, 0, _("redirecting m4's stdin from the temporary file failed"));
202 }
203 close(from_out_fd);
204
205 /*
206 * All m4's output will be gathered in this temporary file
207 * and will be redirected to bison's stdin.
208 */
209 if (to_in_fd < 0)
210 {
211 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
212 error(EXIT_FAILURE, 0, _("opening of a temporary file failed"));
213 }
214 if (dup2(to_in_fd, STDOUT_FILENO) < 0)
215 {
216 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
217 remove_tmp_file(to_in_fd, tmp_file_name[1]);
218 error(EXIT_FAILURE, 0, _("redirecting m4's stdout to a temporary file failed"));
219 }
220 close(to_in_fd);
221
222 /*
223 * Run m4.
224 */
225 child_interrupted = 0;
226 errno = 0;
227 previous_handler = signal(SIGINT, signal_catcher);
228 status = spawnvp(P_WAIT, program, arguments);
229 signal(SIGINT, previous_handler);
230 if (child_interrupted)
231 {
232 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
233 remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
234 error(EXIT_FAILURE, 0, _("subsidiary program '%s' interrupted"), program);
235 }
236 if (status)
237 {
238 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
239 remove_tmp_file(STDOUT_FILENO, tmp_file_name[1]);
240 error(EXIT_FAILURE, 0, _(errno == ENOENT
241 ? "subsidiary program '%s' not found"
242 : status < 1
243 ? "subsidiary program '%s' failed"
244 : "subsidiary program '%s' failed (status=%i, errno=%i)"), program, status, errno);
245 }
246
247
248 /*
249 * Redirect m4's output to bison's stdin.
250 */
251 if (dup2(old_stdout, STDOUT_FILENO) < 0)
252 error(EXIT_FAILURE, 0, "restore of bison's stdout failed");
253 close(old_stdout);
254 to_in_fd = open(tmp_file_name[1], O_RDONLY, S_IRUSR); /* pipe from m4 to bison. */
255 if (to_in_fd < 0)
256 {
257 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
258 error(EXIT_FAILURE, 0, _("opening of tmpfile failed"));
259 }
260 if (dup2(to_in_fd, STDIN_FILENO) < 0)
261 {
262 remove_tmp_file(STDIN_FILENO, tmp_file_name[0]);
263 remove_tmp_file(to_in_fd, tmp_file_name[1]);
264 error(EXIT_FAILURE, -1, "dup2");
265 error(EXIT_FAILURE, 0, _("redirecting bison's stdin from the temporary file failed"));
266 }
267 close(to_in_fd);
268
269
270 fd[1] = STDIN_FILENO;
271 }
272
273
274 /* Free resources, unlink temporary files and restore stdin and stdout. */
275
276 void
reap_subpipe(pid_t pid,char const * program)277 reap_subpipe(pid_t pid, char const *program)
278 {
279 int argc;
280
281 for (argc = 0; arguments[argc]; argc++)
282 free(arguments[argc]);
283 free(arguments);
284
285 if (unlink(tmp_file_name[0]))
286 error(EXIT_FAILURE, 0, _("removing of '%s' failed"), tmp_file_name[0]);
287 if (unlink(tmp_file_name[1]))
288 error(EXIT_FAILURE, 0, _("removing of '%s' failed"), tmp_file_name[1]);
289
290 if (dup2(old_stdin, STDIN_FILENO) < 0)
291 error(EXIT_FAILURE, 0, "restore of bison's stdin failed");
292 close(old_stdin);
293 }
294