Commit | Line | Data |
---|---|---|
ed3ef339 DE |
1 | /* GDB/Scheme support for safe calls into the Guile interpreter. |
2 | ||
42a4f53d | 3 | Copyright (C) 2014-2019 Free Software Foundation, Inc. |
ed3ef339 DE |
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 3 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, see <http://www.gnu.org/licenses/>. */ | |
19 | ||
20 | /* See README file in this directory for implementation notes, coding | |
21 | conventions, et.al. */ | |
22 | ||
23 | #include "defs.h" | |
24 | #include "filenames.h" | |
ed3ef339 | 25 | #include "guile-internal.h" |
b4987c95 | 26 | #include "common/pathstuff.h" |
ed3ef339 DE |
27 | |
28 | /* Struct to marshall args to scscm_safe_call_body. */ | |
29 | ||
30 | struct c_data | |
31 | { | |
c5192092 | 32 | const char *(*func) (void *); |
ed3ef339 DE |
33 | void *data; |
34 | /* An error message or NULL for success. */ | |
c5192092 | 35 | const char *result; |
ed3ef339 DE |
36 | }; |
37 | ||
38 | /* Struct to marshall args through gdbscm_with_catch. */ | |
39 | ||
40 | struct with_catch_data | |
41 | { | |
42 | scm_t_catch_body func; | |
43 | void *data; | |
44 | scm_t_catch_handler unwind_handler; | |
45 | scm_t_catch_handler pre_unwind_handler; | |
46 | ||
47 | /* If EXCP_MATCHER is non-NULL, it is an excp_matcher_func function. | |
48 | If the exception is recognized by it, the exception is recorded as is, | |
49 | without wrapping it in gdb:with-stack. */ | |
50 | excp_matcher_func *excp_matcher; | |
51 | ||
52 | SCM stack; | |
53 | SCM catch_result; | |
54 | }; | |
55 | ||
56 | /* The "body" argument to scm_i_with_continuation_barrier. | |
57 | Invoke the user-supplied function. */ | |
58 | ||
59 | static SCM | |
60 | scscm_safe_call_body (void *d) | |
61 | { | |
62 | struct c_data *data = (struct c_data *) d; | |
63 | ||
64 | data->result = data->func (data->data); | |
65 | ||
66 | return SCM_UNSPECIFIED; | |
67 | } | |
68 | ||
69 | /* A "pre-unwind handler" to scm_c_catch that prints the exception | |
70 | according to "set guile print-stack". */ | |
71 | ||
72 | static SCM | |
73 | scscm_printing_pre_unwind_handler (void *data, SCM key, SCM args) | |
74 | { | |
75 | SCM stack = scm_make_stack (SCM_BOOL_T, scm_list_1 (scm_from_int (2))); | |
76 | ||
77 | gdbscm_print_exception_with_stack (SCM_BOOL_F, stack, key, args); | |
78 | ||
79 | return SCM_UNSPECIFIED; | |
80 | } | |
81 | ||
82 | /* A no-op unwind handler. */ | |
83 | ||
84 | static SCM | |
85 | scscm_nop_unwind_handler (void *data, SCM key, SCM args) | |
86 | { | |
87 | return SCM_UNSPECIFIED; | |
88 | } | |
89 | ||
90 | /* The "pre-unwind handler" to scm_c_catch that records the exception | |
91 | for possible later printing. We do this in the pre-unwind handler because | |
92 | we want the stack to include point where the exception occurred. | |
93 | ||
94 | If DATA is non-NULL, it is an excp_matcher_func function. | |
95 | If the exception is recognized by it, the exception is recorded as is, | |
96 | without wrapping it in gdb:with-stack. */ | |
97 | ||
98 | static SCM | |
99 | scscm_recording_pre_unwind_handler (void *datap, SCM key, SCM args) | |
100 | { | |
9a3c8263 | 101 | struct with_catch_data *data = (struct with_catch_data *) datap; |
ed3ef339 DE |
102 | excp_matcher_func *matcher = data->excp_matcher; |
103 | ||
104 | if (matcher != NULL && matcher (key)) | |
105 | return SCM_UNSPECIFIED; | |
106 | ||
107 | /* There's no need to record the whole stack if we're not going to print it. | |
108 | However, convention is to still print the stack frame in which the | |
109 | exception occurred, even if we're not going to print a full backtrace. | |
110 | For now, keep it simple. */ | |
111 | ||
112 | data->stack = scm_make_stack (SCM_BOOL_T, scm_list_1 (scm_from_int (2))); | |
113 | ||
114 | /* IWBN if we could return the <gdb:exception> here and skip the unwind | |
115 | handler, but it doesn't work that way. If we want to return a | |
116 | <gdb:exception> object from the catch it needs to come from the unwind | |
117 | handler. So what we do is save the stack for later use by the unwind | |
118 | handler. */ | |
119 | ||
120 | return SCM_UNSPECIFIED; | |
121 | } | |
122 | ||
123 | /* Part two of the recording unwind handler. | |
124 | Here we take the stack saved from the pre-unwind handler and create | |
125 | the <gdb:exception> object. */ | |
126 | ||
127 | static SCM | |
128 | scscm_recording_unwind_handler (void *datap, SCM key, SCM args) | |
129 | { | |
9a3c8263 | 130 | struct with_catch_data *data = (struct with_catch_data *) datap; |
ed3ef339 DE |
131 | |
132 | /* We need to record the stack in the exception since we're about to | |
133 | throw and lose the location that got the exception. We do this by | |
134 | wrapping the exception + stack in a new exception. */ | |
135 | ||
136 | if (gdbscm_is_true (data->stack)) | |
137 | return gdbscm_make_exception_with_stack (key, args, data->stack); | |
138 | ||
139 | return gdbscm_make_exception (key, args); | |
140 | } | |
141 | ||
142 | /* Ugh. :-( | |
143 | Guile doesn't export scm_i_with_continuation_barrier which is exactly | |
144 | what we need. To cope, have our own wrapper around scm_c_catch and | |
145 | pass this as the "body" argument to scm_c_with_continuation_barrier. | |
146 | Darn darn darn. */ | |
147 | ||
148 | static void * | |
149 | gdbscm_with_catch (void *data) | |
150 | { | |
9a3c8263 | 151 | struct with_catch_data *d = (struct with_catch_data *) data; |
ed3ef339 DE |
152 | |
153 | d->catch_result | |
154 | = scm_c_catch (SCM_BOOL_T, | |
155 | d->func, d->data, | |
156 | d->unwind_handler, d, | |
157 | d->pre_unwind_handler, d); | |
158 | ||
92fab5a6 AW |
159 | #if HAVE_GUILE_MANUAL_FINALIZATION |
160 | scm_run_finalizers (); | |
161 | #endif | |
162 | ||
ed3ef339 DE |
163 | return NULL; |
164 | } | |
165 | ||
166 | /* A wrapper around scm_with_guile that prints backtraces and exceptions | |
167 | according to "set guile print-stack". | |
168 | The result if NULL if no exception occurred, otherwise it is a statically | |
169 | allocated error message (caller must *not* free). */ | |
170 | ||
c5192092 SM |
171 | const char * |
172 | gdbscm_with_guile (const char *(*func) (void *), void *data) | |
ed3ef339 DE |
173 | { |
174 | struct c_data c_data; | |
175 | struct with_catch_data catch_data; | |
176 | ||
177 | c_data.func = func; | |
178 | c_data.data = data; | |
179 | /* Set this now in case an exception is thrown. */ | |
180 | c_data.result = _("Error while executing Scheme code."); | |
181 | ||
182 | catch_data.func = scscm_safe_call_body; | |
183 | catch_data.data = &c_data; | |
184 | catch_data.unwind_handler = scscm_nop_unwind_handler; | |
185 | catch_data.pre_unwind_handler = scscm_printing_pre_unwind_handler; | |
186 | catch_data.excp_matcher = NULL; | |
187 | catch_data.stack = SCM_BOOL_F; | |
188 | catch_data.catch_result = SCM_UNSPECIFIED; | |
189 | ||
190 | scm_with_guile (gdbscm_with_catch, &catch_data); | |
191 | ||
192 | return c_data.result; | |
193 | } | |
194 | ||
195 | /* Another wrapper of scm_with_guile for use by the safe call/apply routines | |
196 | in this file, as well as for general purpose calling other functions safely. | |
197 | For these we want to record the exception, but leave the possible printing | |
198 | of it to later. */ | |
199 | ||
200 | SCM | |
201 | gdbscm_call_guile (SCM (*func) (void *), void *data, | |
202 | excp_matcher_func *ok_excps) | |
203 | { | |
204 | struct with_catch_data catch_data; | |
205 | ||
206 | catch_data.func = func; | |
207 | catch_data.data = data; | |
208 | catch_data.unwind_handler = scscm_recording_unwind_handler; | |
209 | catch_data.pre_unwind_handler = scscm_recording_pre_unwind_handler; | |
210 | catch_data.excp_matcher = ok_excps; | |
211 | catch_data.stack = SCM_BOOL_F; | |
212 | catch_data.catch_result = SCM_UNSPECIFIED; | |
213 | ||
214 | #if 0 | |
215 | scm_c_with_continuation_barrier (gdbscm_with_catch, &catch_data); | |
216 | #else | |
217 | scm_with_guile (gdbscm_with_catch, &catch_data); | |
218 | #endif | |
219 | ||
220 | return catch_data.catch_result; | |
221 | } | |
222 | \f | |
223 | /* Utilities to safely call Scheme code, catching all exceptions, and | |
224 | preventing continuation capture. | |
225 | The result is the result of calling the function, or if an exception occurs | |
226 | then the result is a <gdb:exception> smob, which can be tested for with | |
227 | gdbscm_is_exception. */ | |
228 | ||
229 | /* Helper for gdbscm_safe_call_0. */ | |
230 | ||
231 | static SCM | |
232 | scscm_call_0_body (void *argsp) | |
233 | { | |
9a3c8263 | 234 | SCM *args = (SCM *) argsp; |
ed3ef339 DE |
235 | |
236 | return scm_call_0 (args[0]); | |
237 | } | |
238 | ||
239 | SCM | |
240 | gdbscm_safe_call_0 (SCM proc, excp_matcher_func *ok_excps) | |
241 | { | |
242 | SCM args[] = { proc }; | |
243 | ||
244 | return gdbscm_call_guile (scscm_call_0_body, args, ok_excps); | |
245 | } | |
246 | ||
247 | /* Helper for gdbscm_safe_call_1. */ | |
248 | ||
249 | static SCM | |
250 | scscm_call_1_body (void *argsp) | |
251 | { | |
9a3c8263 | 252 | SCM *args = (SCM *) argsp; |
ed3ef339 DE |
253 | |
254 | return scm_call_1 (args[0], args[1]); | |
255 | } | |
256 | ||
257 | SCM | |
258 | gdbscm_safe_call_1 (SCM proc, SCM arg0, excp_matcher_func *ok_excps) | |
259 | { | |
260 | SCM args[] = { proc, arg0 }; | |
261 | ||
262 | return gdbscm_call_guile (scscm_call_1_body, args, ok_excps); | |
263 | } | |
264 | ||
265 | /* Helper for gdbscm_safe_call_2. */ | |
266 | ||
267 | static SCM | |
268 | scscm_call_2_body (void *argsp) | |
269 | { | |
9a3c8263 | 270 | SCM *args = (SCM *) argsp; |
ed3ef339 DE |
271 | |
272 | return scm_call_2 (args[0], args[1], args[2]); | |
273 | } | |
274 | ||
275 | SCM | |
276 | gdbscm_safe_call_2 (SCM proc, SCM arg0, SCM arg1, excp_matcher_func *ok_excps) | |
277 | { | |
278 | SCM args[] = { proc, arg0, arg1 }; | |
279 | ||
280 | return gdbscm_call_guile (scscm_call_2_body, args, ok_excps); | |
281 | } | |
282 | ||
283 | /* Helper for gdbscm_safe_call_3. */ | |
284 | ||
285 | static SCM | |
286 | scscm_call_3_body (void *argsp) | |
287 | { | |
9a3c8263 | 288 | SCM *args = (SCM *) argsp; |
ed3ef339 DE |
289 | |
290 | return scm_call_3 (args[0], args[1], args[2], args[3]); | |
291 | } | |
292 | ||
293 | SCM | |
294 | gdbscm_safe_call_3 (SCM proc, SCM arg1, SCM arg2, SCM arg3, | |
295 | excp_matcher_func *ok_excps) | |
296 | { | |
297 | SCM args[] = { proc, arg1, arg2, arg3 }; | |
298 | ||
299 | return gdbscm_call_guile (scscm_call_3_body, args, ok_excps); | |
300 | } | |
301 | ||
302 | /* Helper for gdbscm_safe_call_4. */ | |
303 | ||
304 | static SCM | |
305 | scscm_call_4_body (void *argsp) | |
306 | { | |
9a3c8263 | 307 | SCM *args = (SCM *) argsp; |
ed3ef339 DE |
308 | |
309 | return scm_call_4 (args[0], args[1], args[2], args[3], args[4]); | |
310 | } | |
311 | ||
312 | SCM | |
313 | gdbscm_safe_call_4 (SCM proc, SCM arg1, SCM arg2, SCM arg3, SCM arg4, | |
314 | excp_matcher_func *ok_excps) | |
315 | { | |
316 | SCM args[] = { proc, arg1, arg2, arg3, arg4 }; | |
317 | ||
318 | return gdbscm_call_guile (scscm_call_4_body, args, ok_excps); | |
319 | } | |
320 | ||
321 | /* Helper for gdbscm_safe_apply_1. */ | |
322 | ||
323 | static SCM | |
324 | scscm_apply_1_body (void *argsp) | |
325 | { | |
9a3c8263 | 326 | SCM *args = (SCM *) argsp; |
ed3ef339 DE |
327 | |
328 | return scm_apply_1 (args[0], args[1], args[2]); | |
329 | } | |
330 | ||
331 | SCM | |
332 | gdbscm_safe_apply_1 (SCM proc, SCM arg0, SCM rest, excp_matcher_func *ok_excps) | |
333 | { | |
334 | SCM args[] = { proc, arg0, rest }; | |
335 | ||
336 | return gdbscm_call_guile (scscm_apply_1_body, args, ok_excps); | |
337 | } | |
338 | \f | |
339 | /* Utilities to call Scheme code, not catching exceptions, and | |
340 | not preventing continuation capture. | |
341 | The result is the result of calling the function. | |
342 | If an exception occurs then Guile is left to handle the exception, | |
343 | unwinding the stack as appropriate. | |
344 | ||
345 | USE THESE WITH CARE. | |
346 | Typically these are called from functions that implement Scheme procedures, | |
347 | and we don't want to catch the exception; otherwise it will get printed | |
348 | twice: once when first caught and once if it ends up being rethrown and the | |
349 | rethrow reaches the top repl, which will confuse the user. | |
350 | ||
351 | While these calls just pass the call off to the corresponding Guile | |
352 | procedure, all such calls are routed through these ones to: | |
353 | a) provide a place to put hooks or whatnot in if we need to, | |
354 | b) add "unsafe" to the name to alert the reader. */ | |
355 | ||
356 | SCM | |
357 | gdbscm_unsafe_call_1 (SCM proc, SCM arg0) | |
358 | { | |
359 | return scm_call_1 (proc, arg0); | |
360 | } | |
361 | \f | |
362 | /* Utilities for safely evaluating a Scheme expression string. */ | |
363 | ||
364 | struct eval_scheme_string_data | |
365 | { | |
366 | const char *string; | |
367 | int display_result; | |
368 | }; | |
369 | ||
370 | /* Wrapper to eval a C string in the Guile interpreter. | |
b51a69ee | 371 | This is passed to gdbscm_with_guile. */ |
ed3ef339 | 372 | |
c5192092 | 373 | static const char * |
ed3ef339 DE |
374 | scscm_eval_scheme_string (void *datap) |
375 | { | |
9a3c8263 SM |
376 | struct eval_scheme_string_data *data |
377 | = (struct eval_scheme_string_data *) datap; | |
ed3ef339 DE |
378 | SCM result = scm_c_eval_string (data->string); |
379 | ||
380 | if (data->display_result && !scm_is_eq (result, SCM_UNSPECIFIED)) | |
381 | { | |
382 | SCM port = scm_current_output_port (); | |
383 | ||
384 | scm_write (result, port); | |
385 | scm_newline (port); | |
386 | } | |
387 | ||
388 | /* If we get here the eval succeeded. */ | |
389 | return NULL; | |
390 | } | |
391 | ||
392 | /* Evaluate EXPR in the Guile interpreter, catching all exceptions | |
393 | and preventing continuation capture. | |
394 | The result is NULL if no exception occurred. Otherwise, the exception is | |
395 | printed according to "set guile print-stack" and the result is an error | |
a1a31cb8 | 396 | message. */ |
ed3ef339 | 397 | |
a1a31cb8 | 398 | gdb::unique_xmalloc_ptr<char> |
ed3ef339 DE |
399 | gdbscm_safe_eval_string (const char *string, int display_result) |
400 | { | |
401 | struct eval_scheme_string_data data = { string, display_result }; | |
c5192092 | 402 | const char *result; |
ed3ef339 DE |
403 | |
404 | result = gdbscm_with_guile (scscm_eval_scheme_string, (void *) &data); | |
405 | ||
406 | if (result != NULL) | |
a1a31cb8 | 407 | return gdb::unique_xmalloc_ptr<char> (xstrdup (result)); |
ed3ef339 DE |
408 | return NULL; |
409 | } | |
410 | \f | |
411 | /* Utilities for safely loading Scheme scripts. */ | |
412 | ||
413 | /* Helper function for gdbscm_safe_source_scheme_script. */ | |
414 | ||
c5192092 | 415 | static const char * |
ed3ef339 DE |
416 | scscm_source_scheme_script (void *data) |
417 | { | |
9a3c8263 | 418 | const char *filename = (const char *) data; |
ed3ef339 DE |
419 | |
420 | /* The Guile docs don't specify what the result is. | |
421 | Maybe it's SCM_UNSPECIFIED, but the docs should specify that. :-) */ | |
422 | scm_c_primitive_load_path (filename); | |
423 | ||
424 | /* If we get here the load succeeded. */ | |
425 | return NULL; | |
426 | } | |
427 | ||
428 | /* Try to load a script, catching all exceptions, | |
429 | and preventing continuation capture. | |
430 | The result is NULL if the load succeeded. Otherwise, the exception is | |
431 | printed according to "set guile print-stack" and the result is an error | |
432 | message allocated with malloc, caller must free. */ | |
433 | ||
434 | char * | |
435 | gdbscm_safe_source_script (const char *filename) | |
436 | { | |
437 | /* scm_c_primitive_load_path only looks in %load-path for files with | |
438 | relative paths. An alternative could be to temporarily add "." to | |
439 | %load-path, but we don't want %load-path to be searched. At least not | |
440 | by default. This function is invoked by the "source" GDB command which | |
441 | already has its own path search support. */ | |
14278e1f | 442 | gdb::unique_xmalloc_ptr<char> abs_filename; |
c5192092 | 443 | const char *result; |
ed3ef339 DE |
444 | |
445 | if (!IS_ABSOLUTE_PATH (filename)) | |
446 | { | |
447 | abs_filename = gdb_realpath (filename); | |
14278e1f | 448 | filename = abs_filename.get (); |
ed3ef339 DE |
449 | } |
450 | ||
451 | result = gdbscm_with_guile (scscm_source_scheme_script, | |
452 | (void *) filename); | |
453 | ||
ed3ef339 | 454 | if (result != NULL) |
c5192092 | 455 | return xstrdup (result); |
ed3ef339 DE |
456 | return NULL; |
457 | } | |
458 | \f | |
459 | /* Utility for entering an interactive Guile repl. */ | |
460 | ||
461 | void | |
462 | gdbscm_enter_repl (void) | |
463 | { | |
464 | /* It's unfortunate to have to resort to something like this, but | |
465 | scm_shell doesn't return. :-( I found this code on guile-user@. */ | |
466 | gdbscm_safe_call_1 (scm_c_public_ref ("system repl repl", "start-repl"), | |
467 | scm_from_latin1_symbol ("scheme"), NULL); | |
468 | } |