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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 |
0083c904 BK |
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; |
0083c904 BK |
67 | |
68 | /* | |
1f414ac4 | 69 | * load_data |
0083c904 BK |
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 | */ | |
1f414ac4 | 76 | static char * |
f4dbf936 | 77 | load_data (FILE* fp) |
0083c904 | 78 | { |
1f414ac4 BK |
79 | char *pz_text; |
80 | size_t text_size; | |
81 | char *pz_scan; | |
82 | char z_line[1024]; | |
d1922b48 | 83 | t_bool got_done = BOOL_FALSE; |
0083c904 | 84 | |
1f414ac4 | 85 | text_size = sizeof (z_line) * 2; |
03a9fcb8 | 86 | pz_scan = pz_text = XNEWVEC (char, text_size); |
0083c904 BK |
87 | |
88 | for (;;) | |
89 | { | |
1f414ac4 | 90 | size_t used_ct; |
0083c904 BK |
91 | |
92 | alarm (10); | |
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93 | read_pipe_timeout = BOOL_FALSE; |
94 | if (fgets (z_line, sizeof (z_line), fp) == (char *) NULL) | |
95 | break; | |
96 | ||
97 | if (strncmp (z_line, z_done, sizeof (z_done) - 1) == 0) | |
d1922b48 AO |
98 | { |
99 | got_done = BOOL_TRUE; | |
100 | break; | |
101 | } | |
1f414ac4 BK |
102 | |
103 | strcpy (pz_scan, z_line); | |
104 | pz_scan += strlen (z_line); | |
105 | used_ct = (size_t) (pz_scan - pz_text); | |
106 | ||
107 | if (text_size - used_ct < sizeof (z_line)) | |
108 | { | |
109 | size_t off = (size_t) (pz_scan - pz_text); | |
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110 | |
111 | text_size += 4096; | |
03a9fcb8 | 112 | pz_text = XRESIZEVEC (char, pz_text, text_size); |
1f414ac4 BK |
113 | pz_scan = pz_text + off; |
114 | } | |
0083c904 BK |
115 | } |
116 | ||
117 | alarm (0); | |
d1922b48 | 118 | if (read_pipe_timeout || ! got_done) |
0083c904 | 119 | { |
1f414ac4 | 120 | free ((void *) pz_text); |
0083c904 BK |
121 | return (char *) NULL; |
122 | } | |
123 | ||
92a438d1 | 124 | while ((pz_scan > pz_text) && ISSPACE (pz_scan[-1])) |
1f414ac4 BK |
125 | pz_scan--; |
126 | *pz_scan = NUL; | |
03a9fcb8 | 127 | return XRESIZEVEC (char, pz_text, strlen (pz_text) + 1); |
0083c904 BK |
128 | } |
129 | ||
130 | ||
131 | /* | |
1f414ac4 BK |
132 | * close_server |
133 | * | |
134 | * Make certain the server process is dead, close the | |
135 | * pipes to it and from it, finally NULL out the file pointers | |
0083c904 | 136 | */ |
d1c6a037 | 137 | void |
f4dbf936 | 138 | close_server (void) |
0083c904 | 139 | { |
56ce79f7 BK |
140 | if ( (server_id != NULLPROCESS) |
141 | && (server_master_pid == getpid ())) | |
d1c6a037 BK |
142 | { |
143 | kill ((pid_t) server_id, SIGKILL); | |
144 | server_id = NULLPROCESS; | |
56ce79f7 | 145 | server_master_pid = NOPROCESS; |
d1c6a037 BK |
146 | fclose (server_pair.pf_read); |
147 | fclose (server_pair.pf_write); | |
148 | server_pair.pf_read = server_pair.pf_write = (FILE *) NULL; | |
149 | } | |
0083c904 | 150 | } |
0083c904 | 151 | |
1f414ac4 BK |
152 | /* |
153 | * sig_handler really only handles the timeout and pipe signals. | |
154 | * This ensures that we do not wait forever on a request | |
155 | * to our server, and also that if the server dies, we do not | |
156 | * die from a sigpipe problem. | |
157 | */ | |
158 | static void | |
f4dbf936 | 159 | sig_handler (int signo ATTRIBUTE_UNUSED) |
0083c904 | 160 | { |
f6a65b92 RO |
161 | #ifdef DEBUG |
162 | /* FIXME: this is illegal to do in a signal handler. */ | |
163 | fprintf (stderr, | |
164 | "fixincl ERROR: sig_handler: killed pid %ld due to %s\n", | |
165 | (long) server_id, signo == SIGPIPE ? "SIGPIPE" : "SIGALRM"); | |
166 | #endif | |
1f414ac4 BK |
167 | close_server (); |
168 | read_pipe_timeout = BOOL_TRUE; | |
0083c904 BK |
169 | } |
170 | ||
171 | ||
1f414ac4 BK |
172 | /* |
173 | * server_setup Establish the signal handler for PIPE and ALARM. | |
174 | * Also establishes the current directory to give to the | |
175 | * server process at the start of every server command. | |
176 | */ | |
177 | static void | |
f4dbf936 | 178 | server_setup (void) |
0083c904 | 179 | { |
1f414ac4 | 180 | static int atexit_done = 0; |
c18b00c0 | 181 | char buff [MAXPATHLEN + 1]; |
1f414ac4 BK |
182 | |
183 | if (atexit_done++ == 0) | |
4bc49b49 | 184 | atexit (close_server); |
e9099386 BK |
185 | else |
186 | fputs ("NOTE: server restarted\n", stderr); | |
0083c904 | 187 | |
56ce79f7 BK |
188 | server_master_pid = getpid (); |
189 | ||
1f414ac4 BK |
190 | signal (SIGPIPE, sig_handler); |
191 | signal (SIGALRM, sig_handler); | |
0083c904 | 192 | |
1f414ac4 BK |
193 | fputs ("trap : 1\n", server_pair.pf_write); |
194 | fflush (server_pair.pf_write); | |
c18b00c0 NN |
195 | getcwd (buff, MAXPATHLEN + 1); |
196 | p_cur_dir = xstrdup (buff); | |
0083c904 BK |
197 | } |
198 | ||
bebac701 FL |
199 | /* |
200 | * find_shell | |
201 | * | |
202 | * Locate a shell suitable for use. For various reasons | |
203 | * (like the use of "trap" in server_setup(), it must be a | |
204 | * Bourne-like shell. | |
205 | * | |
206 | * Most of the time, /bin/sh is preferred, but sometimes | |
207 | * it's quite broken (like on Ultrix). autoconf lets you | |
208 | * override with $CONFIG_SHELL, so we do the same. | |
209 | */ | |
210 | ||
2629a114 | 211 | static const char * |
f4dbf936 | 212 | find_shell (void) |
bebac701 FL |
213 | { |
214 | char * shell = getenv ("CONFIG_SHELL"); | |
215 | if (shell) | |
216 | return shell; | |
217 | ||
218 | return "/bin/sh"; | |
219 | } | |
220 | ||
0083c904 | 221 | |
1f414ac4 BK |
222 | /* |
223 | * run_shell | |
224 | * | |
225 | * Run a shell command on the server. The command string | |
226 | * passed in is wrapped inside the sequence: | |
227 | * | |
228 | * cd <original directory> | |
229 | * <command string> | |
230 | * echo | |
231 | * echo <end-of-command-marker> | |
232 | * | |
233 | * This ensures that all commands start at a known place in | |
234 | * the directory structure, that any incomplete output lines | |
235 | * are completed and that our special marker sequence appears on | |
236 | * a line by itself. We have chosen a marker that is | |
237 | * excessively unlikely to be reproduced in normal output: | |
238 | * | |
239 | * "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd" | |
240 | */ | |
0083c904 | 241 | char * |
f4dbf936 | 242 | run_shell (const char* pz_cmd) |
0083c904 | 243 | { |
e9099386 | 244 | tSCC zNoServer[] = "Server not running, cannot run:\n%s\n\n"; |
d1922b48 AO |
245 | t_bool retry = BOOL_TRUE; |
246 | ||
247 | do_retry: | |
1f414ac4 BK |
248 | /* IF the shell server process is not running yet, |
249 | THEN try to start it. */ | |
250 | if (server_id == NULLPROCESS) | |
251 | { | |
bebac701 FL |
252 | def_args[0] = find_shell (); |
253 | ||
1f414ac4 BK |
254 | server_id = proc2_fopen (&server_pair, def_args); |
255 | if (server_id > 0) | |
256 | server_setup (); | |
257 | } | |
0083c904 | 258 | |
1f414ac4 BK |
259 | /* IF it is still not running, THEN return the nil string. */ |
260 | if (server_id <= 0) | |
0083c904 | 261 | { |
e9099386 | 262 | fprintf (stderr, zNoServer, pz_cmd); |
03a9fcb8 | 263 | return XCNEW (char); |
0083c904 BK |
264 | } |
265 | ||
1f414ac4 BK |
266 | /* Make sure the process will pay attention to us, send the |
267 | supplied command, and then have it output a special marker that | |
268 | we can find. */ | |
f6a65b92 | 269 | fprintf (server_pair.pf_write, "cd %s\n%s\n\necho\necho %s\n", |
1f414ac4 BK |
270 | p_cur_dir, pz_cmd, z_done); |
271 | fflush (server_pair.pf_write); | |
0083c904 | 272 | |
1f414ac4 BK |
273 | /* IF the server died and we received a SIGPIPE, |
274 | THEN return an empty string. */ | |
275 | if (server_id == NULLPROCESS) | |
276 | { | |
e9099386 | 277 | fprintf (stderr, zNoServer, pz_cmd); |
03a9fcb8 | 278 | return XCNEW (char); |
1f414ac4 | 279 | } |
0083c904 | 280 | |
1f414ac4 BK |
281 | /* Now try to read back all the data. If we fail due to either a |
282 | sigpipe or sigalrm (timeout), we will return the nil string. */ | |
0083c904 | 283 | { |
1f414ac4 BK |
284 | char *pz = load_data (server_pair.pf_read); |
285 | ||
0083c904 BK |
286 | if (pz == (char *) NULL) |
287 | { | |
d1922b48 AO |
288 | close_server (); |
289 | ||
290 | if (retry) | |
291 | { | |
292 | retry = BOOL_FALSE; | |
293 | goto do_retry; | |
294 | } | |
295 | ||
1f414ac4 BK |
296 | fprintf (stderr, "CLOSING SHELL SERVER - command failure:\n\t%s\n", |
297 | pz_cmd); | |
03a9fcb8 | 298 | pz = XCNEW (char); |
0083c904 | 299 | } |
e9099386 BK |
300 | #ifdef DEBUG |
301 | fprintf( stderr, "run_shell command success: %s\n", pz ); | |
302 | #endif | |
0083c904 BK |
303 | return pz; |
304 | } | |
305 | } |