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0083c904 BK |
1 | |
2 | /* | |
1f414ac4 | 3 | * server.c Set up and handle communications with a server process. |
0083c904 | 4 | * |
f6242907 | 5 | * Server Handling copyright 1992-1999, 2001 The Free Software Foundation |
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6 | * |
7 | * Server Handling is free software. | |
8 | * You may redistribute it and/or modify it under the terms of the | |
9 | * GNU General Public License, as published by the Free Software | |
10 | * Foundation; either version 2, or (at your option) any later version. | |
11 | * | |
12 | * Server Handling is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with Server Handling. See the file "COPYING". If not, | |
19 | * write to: The Free Software Foundation, Inc., | |
20 | * 59 Temple Place - Suite 330, | |
21 | * Boston, MA 02111-1307, USA. | |
22 | * | |
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23 | * As a special exception, The Free Software Foundation gives |
24 | * permission for additional uses of the text contained in his release | |
25 | * of ServerHandler. | |
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26 | * |
27 | * The exception is that, if you link the ServerHandler library with other | |
28 | * files to produce an executable, this does not by itself cause the | |
29 | * resulting executable to be covered by the GNU General Public License. | |
30 | * Your use of that executable is in no way restricted on account of | |
31 | * linking the ServerHandler library code into it. | |
32 | * | |
33 | * This exception does not however invalidate any other reasons why | |
34 | * the executable file might be covered by the GNU General Public License. | |
35 | * | |
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36 | * This exception applies only to the code released by The Free |
37 | * Software Foundation under the name ServerHandler. If you copy code | |
38 | * from other sources under the General Public License into a copy of | |
39 | * ServerHandler, as the General Public License permits, the exception | |
40 | * does not apply to the code that you add in this way. To avoid | |
41 | * misleading anyone as to the status of such modified files, you must | |
42 | * delete this exception notice from them. | |
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43 | * |
44 | * If you write modifications of your own for ServerHandler, it is your | |
45 | * choice whether to permit this exception to apply to your modifications. | |
46 | * If you do not wish that, delete this exception notice. | |
47 | */ | |
0083c904 | 48 | |
4977bab6 | 49 | #include "fixlib.h" |
0083c904 BK |
50 | #include "server.h" |
51 | ||
f6242907 | 52 | STATIC volatile enum t_bool read_pipe_timeout; |
56ce79f7 | 53 | STATIC pid_t server_master_pid = NOPROCESS; |
0083c904 | 54 | |
2629a114 | 55 | tSCC* def_args[] = |
1f414ac4 BK |
56 | { (char *) NULL, (char *) NULL }; |
57 | STATIC t_pf_pair server_pair = | |
58 | { (FILE *) NULL, (FILE *) NULL }; | |
59 | STATIC pid_t server_id = NULLPROCESS; | |
0083c904 BK |
60 | /* |
61 | * Arbitrary text that should not be found in the shell output. | |
62 | * It must be a single line and appear verbatim at the start of | |
63 | * the terminating output line. | |
64 | */ | |
1f414ac4 | 65 | tSCC z_done[] = "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd"; |
2629a114 | 66 | tSCC* p_cur_dir = (char *) NULL; |
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67 | |
68 | /* | |
1f414ac4 | 69 | * load_data |
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70 | * |
71 | * Read data from a file pointer (a pipe to a process in this context) | |
72 | * until we either get EOF or we get a marker line back. | |
73 | * The read data are stored in a malloc-ed string that is truncated | |
74 | * to size at the end. Input is assumed to be an ASCII string. | |
75 | */ | |
6864a6c6 | 76 | static char *load_data PARAMS ((FILE *)); |
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77 | static char * |
78 | load_data (fp) | |
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79 | FILE *fp; |
80 | { | |
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81 | char *pz_text; |
82 | size_t text_size; | |
83 | char *pz_scan; | |
84 | char z_line[1024]; | |
d1922b48 | 85 | t_bool got_done = BOOL_FALSE; |
0083c904 | 86 | |
1f414ac4 | 87 | text_size = sizeof (z_line) * 2; |
f4ce9d90 | 88 | pz_scan = pz_text = xmalloc (text_size); |
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89 | |
90 | for (;;) | |
91 | { | |
1f414ac4 | 92 | size_t used_ct; |
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93 | |
94 | alarm (10); | |
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95 | read_pipe_timeout = BOOL_FALSE; |
96 | if (fgets (z_line, sizeof (z_line), fp) == (char *) NULL) | |
97 | break; | |
98 | ||
99 | if (strncmp (z_line, z_done, sizeof (z_done) - 1) == 0) | |
d1922b48 AO |
100 | { |
101 | got_done = BOOL_TRUE; | |
102 | break; | |
103 | } | |
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104 | |
105 | strcpy (pz_scan, z_line); | |
106 | pz_scan += strlen (z_line); | |
107 | used_ct = (size_t) (pz_scan - pz_text); | |
108 | ||
109 | if (text_size - used_ct < sizeof (z_line)) | |
110 | { | |
111 | size_t off = (size_t) (pz_scan - pz_text); | |
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112 | |
113 | text_size += 4096; | |
f4ce9d90 | 114 | pz_text = xrealloc ((void *) pz_text, text_size); |
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115 | pz_scan = pz_text + off; |
116 | } | |
0083c904 BK |
117 | } |
118 | ||
119 | alarm (0); | |
d1922b48 | 120 | if (read_pipe_timeout || ! got_done) |
0083c904 | 121 | { |
1f414ac4 | 122 | free ((void *) pz_text); |
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123 | return (char *) NULL; |
124 | } | |
125 | ||
92a438d1 | 126 | while ((pz_scan > pz_text) && ISSPACE (pz_scan[-1])) |
1f414ac4 BK |
127 | pz_scan--; |
128 | *pz_scan = NUL; | |
f4ce9d90 | 129 | return xrealloc ((void *) pz_text, strlen (pz_text) + 1); |
0083c904 BK |
130 | } |
131 | ||
132 | ||
133 | /* | |
1f414ac4 BK |
134 | * close_server |
135 | * | |
136 | * Make certain the server process is dead, close the | |
137 | * pipes to it and from it, finally NULL out the file pointers | |
0083c904 | 138 | */ |
d1c6a037 | 139 | void |
1f414ac4 | 140 | close_server () |
0083c904 | 141 | { |
56ce79f7 BK |
142 | if ( (server_id != NULLPROCESS) |
143 | && (server_master_pid == getpid ())) | |
d1c6a037 BK |
144 | { |
145 | kill ((pid_t) server_id, SIGKILL); | |
146 | server_id = NULLPROCESS; | |
56ce79f7 | 147 | server_master_pid = NOPROCESS; |
d1c6a037 BK |
148 | fclose (server_pair.pf_read); |
149 | fclose (server_pair.pf_write); | |
150 | server_pair.pf_read = server_pair.pf_write = (FILE *) NULL; | |
151 | } | |
0083c904 | 152 | } |
0083c904 | 153 | |
1f414ac4 BK |
154 | /* |
155 | * sig_handler really only handles the timeout and pipe signals. | |
156 | * This ensures that we do not wait forever on a request | |
157 | * to our server, and also that if the server dies, we do not | |
158 | * die from a sigpipe problem. | |
159 | */ | |
6864a6c6 | 160 | static void sig_handler PARAMS ((int)); |
1f414ac4 BK |
161 | static void |
162 | sig_handler (signo) | |
6864a6c6 | 163 | int signo ATTRIBUTE_UNUSED; |
0083c904 | 164 | { |
f6a65b92 RO |
165 | #ifdef DEBUG |
166 | /* FIXME: this is illegal to do in a signal handler. */ | |
167 | fprintf (stderr, | |
168 | "fixincl ERROR: sig_handler: killed pid %ld due to %s\n", | |
169 | (long) server_id, signo == SIGPIPE ? "SIGPIPE" : "SIGALRM"); | |
170 | #endif | |
1f414ac4 BK |
171 | close_server (); |
172 | read_pipe_timeout = BOOL_TRUE; | |
0083c904 BK |
173 | } |
174 | ||
175 | ||
1f414ac4 BK |
176 | /* |
177 | * server_setup Establish the signal handler for PIPE and ALARM. | |
178 | * Also establishes the current directory to give to the | |
179 | * server process at the start of every server command. | |
180 | */ | |
6864a6c6 | 181 | static void server_setup PARAMS ((void)); |
1f414ac4 BK |
182 | static void |
183 | server_setup () | |
0083c904 | 184 | { |
1f414ac4 BK |
185 | static int atexit_done = 0; |
186 | ||
187 | if (atexit_done++ == 0) | |
4bc49b49 | 188 | atexit (close_server); |
e9099386 BK |
189 | else |
190 | fputs ("NOTE: server restarted\n", stderr); | |
0083c904 | 191 | |
56ce79f7 BK |
192 | server_master_pid = getpid (); |
193 | ||
1f414ac4 BK |
194 | signal (SIGPIPE, sig_handler); |
195 | signal (SIGALRM, sig_handler); | |
0083c904 | 196 | |
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197 | fputs ("trap : 1\n", server_pair.pf_write); |
198 | fflush (server_pair.pf_write); | |
199 | p_cur_dir = getcwd ((char *) NULL, MAXPATHLEN + 1); | |
0083c904 BK |
200 | } |
201 | ||
bebac701 FL |
202 | /* |
203 | * find_shell | |
204 | * | |
205 | * Locate a shell suitable for use. For various reasons | |
206 | * (like the use of "trap" in server_setup(), it must be a | |
207 | * Bourne-like shell. | |
208 | * | |
209 | * Most of the time, /bin/sh is preferred, but sometimes | |
210 | * it's quite broken (like on Ultrix). autoconf lets you | |
211 | * override with $CONFIG_SHELL, so we do the same. | |
212 | */ | |
213 | ||
2629a114 BK |
214 | static const char *find_shell PARAMS ((void)); |
215 | static const char * | |
bebac701 FL |
216 | find_shell () |
217 | { | |
218 | char * shell = getenv ("CONFIG_SHELL"); | |
219 | if (shell) | |
220 | return shell; | |
221 | ||
222 | return "/bin/sh"; | |
223 | } | |
224 | ||
0083c904 | 225 | |
1f414ac4 BK |
226 | /* |
227 | * run_shell | |
228 | * | |
229 | * Run a shell command on the server. The command string | |
230 | * passed in is wrapped inside the sequence: | |
231 | * | |
232 | * cd <original directory> | |
233 | * <command string> | |
234 | * echo | |
235 | * echo <end-of-command-marker> | |
236 | * | |
237 | * This ensures that all commands start at a known place in | |
238 | * the directory structure, that any incomplete output lines | |
239 | * are completed and that our special marker sequence appears on | |
240 | * a line by itself. We have chosen a marker that is | |
241 | * excessively unlikely to be reproduced in normal output: | |
242 | * | |
243 | * "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd" | |
244 | */ | |
0083c904 | 245 | char * |
1f414ac4 BK |
246 | run_shell (pz_cmd) |
247 | const char *pz_cmd; | |
0083c904 | 248 | { |
e9099386 | 249 | tSCC zNoServer[] = "Server not running, cannot run:\n%s\n\n"; |
d1922b48 AO |
250 | t_bool retry = BOOL_TRUE; |
251 | ||
252 | do_retry: | |
1f414ac4 BK |
253 | /* IF the shell server process is not running yet, |
254 | THEN try to start it. */ | |
255 | if (server_id == NULLPROCESS) | |
256 | { | |
bebac701 FL |
257 | def_args[0] = find_shell (); |
258 | ||
1f414ac4 BK |
259 | server_id = proc2_fopen (&server_pair, def_args); |
260 | if (server_id > 0) | |
261 | server_setup (); | |
262 | } | |
0083c904 | 263 | |
1f414ac4 BK |
264 | /* IF it is still not running, THEN return the nil string. */ |
265 | if (server_id <= 0) | |
0083c904 | 266 | { |
e9099386 | 267 | fprintf (stderr, zNoServer, pz_cmd); |
f4ce9d90 | 268 | return xcalloc (1, 1); |
0083c904 BK |
269 | } |
270 | ||
1f414ac4 BK |
271 | /* Make sure the process will pay attention to us, send the |
272 | supplied command, and then have it output a special marker that | |
273 | we can find. */ | |
f6a65b92 | 274 | fprintf (server_pair.pf_write, "cd %s\n%s\n\necho\necho %s\n", |
1f414ac4 BK |
275 | p_cur_dir, pz_cmd, z_done); |
276 | fflush (server_pair.pf_write); | |
0083c904 | 277 | |
1f414ac4 BK |
278 | /* IF the server died and we received a SIGPIPE, |
279 | THEN return an empty string. */ | |
280 | if (server_id == NULLPROCESS) | |
281 | { | |
e9099386 | 282 | fprintf (stderr, zNoServer, pz_cmd); |
f4ce9d90 | 283 | return xcalloc (1, 1); |
1f414ac4 | 284 | } |
0083c904 | 285 | |
1f414ac4 BK |
286 | /* Now try to read back all the data. If we fail due to either a |
287 | sigpipe or sigalrm (timeout), we will return the nil string. */ | |
0083c904 | 288 | { |
1f414ac4 BK |
289 | char *pz = load_data (server_pair.pf_read); |
290 | ||
0083c904 BK |
291 | if (pz == (char *) NULL) |
292 | { | |
d1922b48 AO |
293 | close_server (); |
294 | ||
295 | if (retry) | |
296 | { | |
297 | retry = BOOL_FALSE; | |
298 | goto do_retry; | |
299 | } | |
300 | ||
1f414ac4 BK |
301 | fprintf (stderr, "CLOSING SHELL SERVER - command failure:\n\t%s\n", |
302 | pz_cmd); | |
f4ce9d90 | 303 | pz = xcalloc (1, 1); |
0083c904 | 304 | } |
e9099386 BK |
305 | #ifdef DEBUG |
306 | fprintf( stderr, "run_shell command success: %s\n", pz ); | |
307 | #endif | |
0083c904 BK |
308 | return pz; |
309 | } | |
310 | } |