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3fbdd536 | 1 | /* Fork a Unix child process, and set up to debug it, for GDB. |
ba47c66a | 2 | Copyright 1990, 1991, 1992, 1993, 1994 Free Software Foundation, Inc. |
3fbdd536 JG |
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" | |
ba47c66a | 22 | #include <string.h> |
3fbdd536 JG |
23 | #include "frame.h" /* required by inferior.h */ |
24 | #include "inferior.h" | |
25 | #include "target.h" | |
26 | #include "wait.h" | |
27 | #include "gdbcore.h" | |
c18b613a | 28 | #include "terminal.h" |
100f92e2 | 29 | #include "thread.h" |
3fbdd536 JG |
30 | |
31 | #include <signal.h> | |
32 | ||
33 | #ifdef SET_STACK_LIMIT_HUGE | |
34 | #include <sys/time.h> | |
35 | #include <sys/resource.h> | |
36 | ||
37 | extern int original_stack_limit; | |
38 | #endif /* SET_STACK_LIMIT_HUGE */ | |
39 | ||
40 | extern char **environ; | |
41 | ||
3fbdd536 JG |
42 | #ifndef SHELL_FILE |
43 | #define SHELL_FILE "/bin/sh" | |
44 | #endif | |
45 | ||
08f74b92 JK |
46 | /* Start an inferior Unix child process and sets inferior_pid to its pid. |
47 | EXEC_FILE is the file to run. | |
48 | ALLARGS is a string containing the arguments to the program. | |
49 | ENV is the environment vector to pass. SHELL_FILE is the shell file, | |
50 | or NULL if we should pick one. Errors reported with error(). */ | |
51 | ||
3fbdd536 | 52 | void |
08f74b92 JK |
53 | fork_inferior (exec_file, allargs, env, traceme_fun, init_trace_fun, |
54 | shell_file) | |
3fbdd536 JG |
55 | char *exec_file; |
56 | char *allargs; | |
57 | char **env; | |
58 | void (*traceme_fun) PARAMS ((void)); | |
59 | void (*init_trace_fun) PARAMS ((int)); | |
08f74b92 | 60 | char *shell_file; |
3fbdd536 JG |
61 | { |
62 | int pid; | |
63 | char *shell_command; | |
3fbdd536 JG |
64 | static char default_shell_file[] = SHELL_FILE; |
65 | int len; | |
3fbdd536 JG |
66 | /* Set debug_fork then attach to the child while it sleeps, to debug. */ |
67 | static int debug_fork = 0; | |
68 | /* This is set to the result of setpgrp, which if vforked, will be visible | |
69 | to you in the parent process. It's only used by humans for debugging. */ | |
70 | static int debug_setpgrp = 657473; | |
71 | char **save_our_env; | |
72 | ||
73 | /* If no exec file handed to us, get it from the exec-file command -- with | |
74 | a good, common error message if none is specified. */ | |
75 | if (exec_file == 0) | |
76 | exec_file = get_exec_file(1); | |
77 | ||
78 | /* The user might want tilde-expansion, and in general probably wants | |
79 | the program to behave the same way as if run from | |
80 | his/her favorite shell. So we let the shell run it for us. | |
4142aab8 | 81 | FIXME-maybe, we might want a "set shell" command so the user can change |
08f74b92 JK |
82 | the shell from within GDB (if so, change callers which pass in a non-NULL |
83 | shell_file too). */ | |
84 | if (shell_file == NULL) | |
85 | shell_file = getenv ("SHELL"); | |
3fbdd536 JG |
86 | if (shell_file == NULL) |
87 | shell_file = default_shell_file; | |
3768398d JK |
88 | |
89 | /* Multiplying the length of exec_file by 4 is to account for the fact | |
90 | that it may expand when quoted; it is a worst-case number based on | |
91 | every character being '. */ | |
92 | len = 5 + 4 * strlen (exec_file) + 1 + strlen (allargs) + 1 + /*slop*/ 12; | |
3fbdd536 JG |
93 | /* If desired, concat something onto the front of ALLARGS. |
94 | SHELL_COMMAND is the result. */ | |
95 | #ifdef SHELL_COMMAND_CONCAT | |
96 | shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + len); | |
97 | strcpy (shell_command, SHELL_COMMAND_CONCAT); | |
98 | #else | |
99 | shell_command = (char *) alloca (len); | |
100 | shell_command[0] = '\0'; | |
101 | #endif | |
102 | strcat (shell_command, "exec "); | |
3768398d | 103 | |
38bbfd37 | 104 | /* Now add exec_file, quoting as necessary. */ |
3768398d JK |
105 | { |
106 | char *p; | |
38bbfd37 | 107 | int need_to_quote; |
3768398d | 108 | |
38bbfd37 JK |
109 | /* Quoting in this style is said to work with all shells. But csh |
110 | on IRIX 4.0.1 can't deal with it. So we only quote it if we need | |
111 | to. */ | |
112 | p = exec_file; | |
113 | while (1) | |
3768398d | 114 | { |
38bbfd37 JK |
115 | switch (*p) |
116 | { | |
117 | case '\'': | |
118 | case '"': | |
119 | case '(': | |
120 | case ')': | |
121 | case '$': | |
122 | case '&': | |
123 | case ';': | |
124 | case '<': | |
125 | case '>': | |
126 | case ' ': | |
127 | case '\n': | |
128 | case '\t': | |
129 | need_to_quote = 1; | |
130 | goto end_scan; | |
131 | ||
132 | case '\0': | |
133 | need_to_quote = 0; | |
134 | goto end_scan; | |
135 | ||
136 | default: | |
137 | break; | |
138 | } | |
139 | ++p; | |
3768398d | 140 | } |
38bbfd37 JK |
141 | end_scan: |
142 | if (need_to_quote) | |
143 | { | |
144 | strcat (shell_command, "'"); | |
145 | for (p = exec_file; *p != '\0'; ++p) | |
146 | { | |
147 | if (*p == '\'') | |
148 | strcat (shell_command, "'\\''"); | |
149 | else | |
150 | strncat (shell_command, p, 1); | |
151 | } | |
152 | strcat (shell_command, "'"); | |
153 | } | |
154 | else | |
155 | strcat (shell_command, exec_file); | |
3768398d JK |
156 | } |
157 | ||
3fbdd536 JG |
158 | strcat (shell_command, " "); |
159 | strcat (shell_command, allargs); | |
160 | ||
161 | /* exec is said to fail if the executable is open. */ | |
162 | close_exec_file (); | |
163 | ||
164 | /* Retain a copy of our environment variables, since the child will | |
165 | replace the value of environ and if we're vforked, we have to | |
166 | restore it. */ | |
167 | save_our_env = environ; | |
168 | ||
169 | /* Tell the terminal handling subsystem what tty we plan to run on; | |
170 | it will just record the information for later. */ | |
171 | ||
172 | new_tty_prefork (inferior_io_terminal); | |
173 | ||
174 | /* It is generally good practice to flush any possible pending stdio | |
175 | output prior to doing a fork, to avoid the possibility of both the | |
176 | parent and child flushing the same data after the fork. */ | |
177 | ||
199b2450 TL |
178 | gdb_flush (gdb_stdout); |
179 | gdb_flush (gdb_stderr); | |
3fbdd536 JG |
180 | |
181 | #if defined(USG) && !defined(HAVE_VFORK) | |
182 | pid = fork (); | |
183 | #else | |
184 | if (debug_fork) | |
185 | pid = fork (); | |
186 | else | |
187 | pid = vfork (); | |
188 | #endif | |
189 | ||
190 | if (pid < 0) | |
191 | perror_with_name ("vfork"); | |
192 | ||
193 | if (pid == 0) | |
194 | { | |
195 | if (debug_fork) | |
196 | sleep (debug_fork); | |
197 | ||
3fbdd536 | 198 | /* Run inferior in a separate process group. */ |
c2e247c4 | 199 | debug_setpgrp = gdb_setpgid (); |
3fbdd536 JG |
200 | if (debug_setpgrp == -1) |
201 | perror("setpgrp failed in child"); | |
3fbdd536 JG |
202 | |
203 | #ifdef SET_STACK_LIMIT_HUGE | |
204 | /* Reset the stack limit back to what it was. */ | |
205 | { | |
206 | struct rlimit rlim; | |
207 | ||
208 | getrlimit (RLIMIT_STACK, &rlim); | |
209 | rlim.rlim_cur = original_stack_limit; | |
210 | setrlimit (RLIMIT_STACK, &rlim); | |
211 | } | |
212 | #endif /* SET_STACK_LIMIT_HUGE */ | |
213 | ||
214 | /* Ask the tty subsystem to switch to the one we specified earlier | |
215 | (or to share the current terminal, if none was specified). */ | |
216 | ||
217 | new_tty (); | |
218 | ||
219 | /* Changing the signal handlers for the inferior after | |
220 | a vfork can also change them for the superior, so we don't mess | |
221 | with signals here. See comments in | |
222 | initialize_signals for how we get the right signal handlers | |
223 | for the inferior. */ | |
224 | ||
225 | /* "Trace me, Dr. Memory!" */ | |
226 | (*traceme_fun) (); | |
227 | ||
228 | /* There is no execlpe call, so we have to set the environment | |
229 | for our child in the global variable. If we've vforked, this | |
230 | clobbers the parent, but environ is restored a few lines down | |
231 | in the parent. By the way, yes we do need to look down the | |
232 | path to find $SHELL. Rich Pixley says so, and I agree. */ | |
233 | environ = env; | |
234 | execlp (shell_file, shell_file, "-c", shell_command, (char *)0); | |
235 | ||
199b2450 | 236 | fprintf_unfiltered (gdb_stderr, "Cannot exec %s: %s.\n", shell_file, |
3fbdd536 | 237 | safe_strerror (errno)); |
199b2450 | 238 | gdb_flush (gdb_stderr); |
3fbdd536 JG |
239 | _exit (0177); |
240 | } | |
241 | ||
242 | /* Restore our environment in case a vforked child clob'd it. */ | |
243 | environ = save_our_env; | |
244 | ||
de43d7d0 SG |
245 | init_thread_list(); |
246 | ||
bc28a06c JK |
247 | inferior_pid = pid; /* Needed for wait_for_inferior stuff below */ |
248 | ||
3fbdd536 JG |
249 | /* Now that we have a child process, make it our target, and |
250 | initialize anything target-vector-specific that needs initializing. */ | |
251 | (*init_trace_fun)(pid); | |
252 | ||
bc28a06c JK |
253 | /* We are now in the child process of interest, having exec'd the |
254 | correct program, and are poised at the first instruction of the | |
255 | new program. */ | |
256 | #ifdef SOLIB_CREATE_INFERIOR_HOOK | |
257 | SOLIB_CREATE_INFERIOR_HOOK (pid); | |
258 | #endif | |
259 | } | |
260 | ||
261 | /* Accept NTRAPS traps from the inferior. */ | |
262 | ||
263 | void | |
264 | startup_inferior (ntraps) | |
265 | int ntraps; | |
266 | { | |
267 | int pending_execs = ntraps; | |
268 | int terminal_initted; | |
269 | ||
5d76c8e6 JK |
270 | /* The process was started by the fork that created it, |
271 | but it will have stopped one instruction after execing the shell. | |
272 | Here we must get it up to actual execution of the real program. */ | |
3fbdd536 | 273 | |
3fbdd536 JG |
274 | clear_proceed_status (); |
275 | ||
3fbdd536 JG |
276 | init_wait_for_inferior (); |
277 | ||
01dfd415 | 278 | terminal_initted = 0; |
3fbdd536 JG |
279 | |
280 | while (1) | |
281 | { | |
282 | stop_soon_quietly = 1; /* Make wait_for_inferior be quiet */ | |
283 | wait_for_inferior (); | |
67ac9759 | 284 | if (stop_signal != TARGET_SIGNAL_TRAP) |
3fbdd536 JG |
285 | { |
286 | /* Let shell child handle its own signals in its own way */ | |
287 | /* FIXME, what if child has exit()ed? Must exit loop somehow */ | |
288 | resume (0, stop_signal); | |
289 | } | |
290 | else | |
291 | { | |
292 | /* We handle SIGTRAP, however; it means child did an exec. */ | |
01dfd415 JK |
293 | if (!terminal_initted) |
294 | { | |
295 | /* Now that the child has exec'd we know it has already set its | |
296 | process group. On POSIX systems, tcsetpgrp will fail with | |
297 | EPERM if we try it before the child's setpgid. */ | |
298 | ||
299 | /* Set up the "saved terminal modes" of the inferior | |
300 | based on what modes we are starting it with. */ | |
301 | target_terminal_init (); | |
302 | ||
303 | /* Install inferior's terminal modes. */ | |
304 | target_terminal_inferior (); | |
305 | ||
306 | terminal_initted = 1; | |
307 | } | |
3fbdd536 JG |
308 | if (0 == --pending_execs) |
309 | break; | |
67ac9759 | 310 | resume (0, TARGET_SIGNAL_0); /* Just make it go on */ |
3fbdd536 JG |
311 | } |
312 | } | |
313 | stop_soon_quietly = 0; | |
3fbdd536 | 314 | } |