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3fbdd536 JG |
1 | /* Fork a Unix child process, and set up to debug it, for GDB. |
2 | Copyright 1990, 1991, 1992 Free Software Foundation, Inc. | |
3 | Contributed by Cygnus Support. | |
4 | ||
5 | This file is part of GDB. | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program 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 this program; if not, write to the Free Software | |
19 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
20 | ||
21 | #include "defs.h" | |
22 | #include "frame.h" /* required by inferior.h */ | |
23 | #include "inferior.h" | |
24 | #include "target.h" | |
25 | #include "wait.h" | |
26 | #include "gdbcore.h" | |
c18b613a | 27 | #include "terminal.h" |
100f92e2 | 28 | #include "thread.h" |
3fbdd536 JG |
29 | |
30 | #include <signal.h> | |
31 | ||
32 | #ifdef SET_STACK_LIMIT_HUGE | |
33 | #include <sys/time.h> | |
34 | #include <sys/resource.h> | |
35 | ||
36 | extern int original_stack_limit; | |
37 | #endif /* SET_STACK_LIMIT_HUGE */ | |
38 | ||
39 | extern char **environ; | |
40 | ||
3fbdd536 JG |
41 | #ifndef SHELL_FILE |
42 | #define SHELL_FILE "/bin/sh" | |
43 | #endif | |
44 | ||
08f74b92 JK |
45 | /* Start an inferior Unix child process and sets inferior_pid to its pid. |
46 | EXEC_FILE is the file to run. | |
47 | ALLARGS is a string containing the arguments to the program. | |
48 | ENV is the environment vector to pass. SHELL_FILE is the shell file, | |
49 | or NULL if we should pick one. Errors reported with error(). */ | |
50 | ||
3fbdd536 | 51 | void |
08f74b92 JK |
52 | fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun, |
53 | shell_file) | |
3fbdd536 JG |
54 | char *exec_file; |
55 | char *allargs; | |
56 | char **env; | |
57 | void (*traceme_fun) PARAMS ((void)); | |
58 | void (*init_trace_fun) PARAMS ((int)); | |
08f74b92 | 59 | char *shell_file; |
3fbdd536 JG |
60 | { |
61 | int pid; | |
62 | char *shell_command; | |
3fbdd536 JG |
63 | static char default_shell_file[] = SHELL_FILE; |
64 | int len; | |
3fbdd536 JG |
65 | /* Set debug_fork then attach to the child while it sleeps, to debug. */ |
66 | static int debug_fork = 0; | |
67 | /* This is set to the result of setpgrp, which if vforked, will be visible | |
68 | to you in the parent process. It's only used by humans for debugging. */ | |
69 | static int debug_setpgrp = 657473; | |
70 | char **save_our_env; | |
71 | ||
72 | /* If no exec file handed to us, get it from the exec-file command -- with | |
73 | a good, common error message if none is specified. */ | |
74 | if (exec_file == 0) | |
75 | exec_file = get_exec_file(1); | |
76 | ||
77 | /* The user might want tilde-expansion, and in general probably wants | |
78 | the program to behave the same way as if run from | |
79 | his/her favorite shell. So we let the shell run it for us. | |
4142aab8 | 80 | FIXME-maybe, we might want a "set shell" command so the user can change |
08f74b92 JK |
81 | the shell from within GDB (if so, change callers which pass in a non-NULL |
82 | shell_file too). */ | |
83 | if (shell_file == NULL) | |
84 | shell_file = getenv ("SHELL"); | |
3fbdd536 JG |
85 | if (shell_file == NULL) |
86 | shell_file = default_shell_file; | |
3768398d JK |
87 | |
88 | /* Multiplying the length of exec_file by 4 is to account for the fact | |
89 | that it may expand when quoted; it is a worst-case number based on | |
90 | every character being '. */ | |
91 | len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 12; | |
3fbdd536 JG |
92 | /* If desired, concat something onto the front of ALLARGS. |
93 | SHELL_COMMAND is the result. */ | |
94 | #ifdef SHELL_COMMAND_CONCAT | |
95 | shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len); | |
96 | strcpy (shell_command, SHELL_COMMAND_CONCAT); | |
97 | #else | |
98 | shell_command = (char *) alloca (len); | |
99 | shell_command[0] = '\0'; | |
100 | #endif | |
101 | strcat (shell_command, "exec "); | |
3768398d | 102 | |
38bbfd37 | 103 | /* Now add exec_file, quoting as necessary. */ |
3768398d JK |
104 | { |
105 | char *p; | |
38bbfd37 | 106 | int need_to_quote; |
3768398d | 107 | |
38bbfd37 JK |
108 | /* Quoting in this style is said to work with all shells. But csh |
109 | on IRIX 4.0.1 can't deal with it. So we only quote it if we need | |
110 | to. */ | |
111 | p = exec_file; | |
112 | while (1) | |
3768398d | 113 | { |
38bbfd37 JK |
114 | switch (*p) |
115 | { | |
116 | case '\'': | |
117 | case '"': | |
118 | case '(': | |
119 | case ')': | |
120 | case '$': | |
121 | case '&': | |
122 | case ';': | |
123 | case '<': | |
124 | case '>': | |
125 | case ' ': | |
126 | case '\n': | |
127 | case '\t': | |
128 | need_to_quote = 1; | |
129 | goto end_scan; | |
130 | ||
131 | case '\0': | |
132 | need_to_quote = 0; | |
133 | goto end_scan; | |
134 | ||
135 | default: | |
136 | break; | |
137 | } | |
138 | ++p; | |
3768398d | 139 | } |
38bbfd37 JK |
140 | end_scan: |
141 | if (need_to_quote) | |
142 | { | |
143 | strcat (shell_command, "'"); | |
144 | for (p = exec_file; *p != '\0'; ++p) | |
145 | { | |
146 | if (*p == '\'') | |
147 | strcat (shell_command, "'\\''"); | |
148 | else | |
149 | strncat (shell_command, p, 1); | |
150 | } | |
151 | strcat (shell_command, "'"); | |
152 | } | |
153 | else | |
154 | strcat (shell_command, exec_file); | |
3768398d JK |
155 | } |
156 | ||
3fbdd536 JG |
157 | strcat (shell_command, " "); |
158 | strcat (shell_command, allargs); | |
159 | ||
160 | /* exec is said to fail if the executable is open. */ | |
161 | close_exec_file (); | |
162 | ||
163 | /* Retain a copy of our environment variables, since the child will | |
164 | replace the value of environ and if we're vforked, we have to | |
165 | restore it. */ | |
166 | save_our_env = environ; | |
167 | ||
168 | /* Tell the terminal handling subsystem what tty we plan to run on; | |
169 | it will just record the information for later. */ | |
170 | ||
171 | new_tty_prefork (inferior_io_terminal); | |
172 | ||
173 | /* It is generally good practice to flush any possible pending stdio | |
174 | output prior to doing a fork, to avoid the possibility of both the | |
175 | parent and child flushing the same data after the fork. */ | |
176 | ||
199b2450 TL |
177 | gdb_flush (gdb_stdout); |
178 | gdb_flush (gdb_stderr); | |
3fbdd536 JG |
179 | |
180 | #if defined(USG) && !defined(HAVE_VFORK) | |
181 | pid = fork (); | |
182 | #else | |
183 | if (debug_fork) | |
184 | pid = fork (); | |
185 | else | |
186 | pid = vfork (); | |
187 | #endif | |
188 | ||
189 | if (pid < 0) | |
190 | perror_with_name ("vfork"); | |
191 | ||
192 | if (pid == 0) | |
193 | { | |
194 | if (debug_fork) | |
195 | sleep (debug_fork); | |
196 | ||
3fbdd536 | 197 | /* Run inferior in a separate process group. */ |
c2e247c4 | 198 | debug_setpgrp = gdb_setpgid (); |
3fbdd536 JG |
199 | if (debug_setpgrp == -1) |
200 | perror("setpgrp failed in child"); | |
3fbdd536 JG |
201 | |
202 | #ifdef SET_STACK_LIMIT_HUGE | |
203 | /* Reset the stack limit back to what it was. */ | |
204 | { | |
205 | struct rlimit rlim; | |
206 | ||
207 | getrlimit (RLIMIT_STACK, &rlim); | |
208 | rlim.rlim_cur = original_stack_limit; | |
209 | setrlimit (RLIMIT_STACK, &rlim); | |
210 | } | |
211 | #endif /* SET_STACK_LIMIT_HUGE */ | |
212 | ||
213 | /* Ask the tty subsystem to switch to the one we specified earlier | |
214 | (or to share the current terminal, if none was specified). */ | |
215 | ||
216 | new_tty (); | |
217 | ||
218 | /* Changing the signal handlers for the inferior after | |
219 | a vfork can also change them for the superior, so we don't mess | |
220 | with signals here. See comments in | |
221 | initialize_signals for how we get the right signal handlers | |
222 | for the inferior. */ | |
223 | ||
224 | /* "Trace me, Dr. Memory!" */ | |
225 | (*traceme_fun) (); | |
226 | ||
227 | /* There is no execlpe call, so we have to set the environment | |
228 | for our child in the global variable. If we've vforked, this | |
229 | clobbers the parent, but environ is restored a few lines down | |
230 | in the parent. By the way, yes we do need to look down the | |
231 | path to find $SHELL. Rich Pixley says so, and I agree. */ | |
232 | environ = env; | |
233 | execlp (shell_file, shell_file, "-c", shell_command, (char *)0); | |
234 | ||
199b2450 | 235 | fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file, |
3fbdd536 | 236 | safe_strerror (errno)); |
199b2450 | 237 | gdb_flush (gdb_stderr); |
3fbdd536 JG |
238 | _exit (0177); |
239 | } | |
240 | ||
241 | /* Restore our environment in case a vforked child clob'd it. */ | |
242 | environ = save_our_env; | |
243 | ||
de43d7d0 SG |
244 | init_thread_list(); |
245 | ||
bc28a06c JK |
246 | inferior_pid = pid; /* Needed for wait_for_inferior stuff below */ |
247 | ||
3fbdd536 JG |
248 | /* Now that we have a child process, make it our target, and |
249 | initialize anything target-vector-specific that needs initializing. */ | |
250 | (*init_trace_fun)(pid); | |
251 | ||
bc28a06c JK |
252 | /* We are now in the child process of interest, having exec'd the |
253 | correct program, and are poised at the first instruction of the | |
254 | new program. */ | |
255 | #ifdef SOLIB_CREATE_INFERIOR_HOOK | |
256 | SOLIB_CREATE_INFERIOR_HOOK (pid); | |
257 | #endif | |
258 | } | |
259 | ||
260 | /* Accept NTRAPS traps from the inferior. */ | |
261 | ||
262 | void | |
263 | startup_inferior (ntraps) | |
264 | int ntraps; | |
265 | { | |
266 | int pending_execs = ntraps; | |
267 | int terminal_initted; | |
268 | ||
5d76c8e6 JK |
269 | /* The process was started by the fork that created it, |
270 | but it will have stopped one instruction after execing the shell. | |
271 | Here we must get it up to actual execution of the real program. */ | |
3fbdd536 | 272 | |
3fbdd536 JG |
273 | clear_proceed_status (); |
274 | ||
3fbdd536 JG |
275 | init_wait_for_inferior (); |
276 | ||
01dfd415 | 277 | terminal_initted = 0; |
3fbdd536 JG |
278 | |
279 | while (1) | |
280 | { | |
281 | stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */ | |
282 | wait_for_inferior (); | |
67ac9759 | 283 | if (stop_signal != TARGET_SIGNAL_TRAP) |
3fbdd536 JG |
284 | { |
285 | /* Let shell child handle its own signals in its own way */ | |
286 | /* FIXME, what if child has exit()ed? Must exit loop somehow */ | |
287 | resume (0, stop_signal); | |
288 | } | |
289 | else | |
290 | { | |
291 | /* We handle SIGTRAP, however; it means child did an exec. */ | |
01dfd415 JK |
292 | if (!terminal_initted) |
293 | { | |
294 | /* Now that the child has exec'd we know it has already set its | |
295 | process group. On POSIX systems, tcsetpgrp will fail with | |
296 | EPERM if we try it before the child's setpgid. */ | |
297 | ||
298 | /* Set up the "saved terminal modes" of the inferior | |
299 | based on what modes we are starting it with. */ | |
300 | target_terminal_init (); | |
301 | ||
302 | /* Install inferior's terminal modes. */ | |
303 | target_terminal_inferior (); | |
304 | ||
305 | terminal_initted = 1; | |
306 | } | |
3fbdd536 JG |
307 | if (0 == --pending_execs) |
308 | break; | |
67ac9759 | 309 | resume (0, TARGET_SIGNAL_0); /* Just make it go on */ |
3fbdd536 JG |
310 | } |
311 | } | |
312 | stop_soon_quietly = 0; | |
3fbdd536 | 313 | } |