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1479465f GJ |
1 | /* |
2 | * libdpkg - Debian packaging suite library routines | |
3 | * ehandle.c - error handling | |
4 | * | |
5 | * Copyright © 1994,1995 Ian Jackson <ijackson@chiark.greenend.org.uk> | |
6 | * Copyright © 2008-2014 Guillem Jover <guillem@debian.org> | |
7 | * | |
8 | * This is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program. If not, see <https://www.gnu.org/licenses/>. | |
20 | */ | |
21 | ||
22 | #include <config.h> | |
23 | #include <compat.h> | |
24 | ||
25 | #include <errno.h> | |
26 | #include <string.h> | |
27 | #include <unistd.h> | |
28 | #include <stdarg.h> | |
29 | #include <stdlib.h> | |
30 | #include <stdio.h> | |
31 | ||
32 | #include <dpkg/macros.h> | |
33 | #include <dpkg/i18n.h> | |
34 | #include <dpkg/progname.h> | |
35 | #include <dpkg/color.h> | |
36 | #include <dpkg/ehandle.h> | |
37 | ||
38 | /* Incremented when we do some kind of generally necessary operation, | |
39 | * so that loops &c know to quit if we take an error exit. Decremented | |
40 | * again afterwards. */ | |
41 | volatile int onerr_abort = 0; | |
42 | ||
43 | #define NCALLS 2 | |
44 | ||
45 | struct cleanup_entry { | |
46 | struct cleanup_entry *next; | |
47 | struct { | |
48 | int mask; | |
49 | void (*call)(int argc, void **argv); | |
50 | } calls[NCALLS]; | |
51 | int cpmask, cpvalue; | |
52 | int argc; | |
53 | void *argv[1]; | |
54 | }; | |
55 | ||
56 | struct error_context { | |
57 | struct error_context *next; | |
58 | ||
59 | enum { | |
60 | HANDLER_TYPE_FUNC, | |
61 | HANDLER_TYPE_JUMP, | |
62 | } handler_type; | |
63 | ||
64 | union { | |
65 | error_handler_func *func; | |
66 | jmp_buf *jump; | |
67 | } handler; | |
68 | ||
69 | struct { | |
70 | error_printer_func *func; | |
71 | const void *data; | |
72 | } printer; | |
73 | ||
74 | struct cleanup_entry *cleanups; | |
75 | ||
76 | char *errmsg; | |
77 | }; | |
78 | ||
79 | static struct error_context *volatile econtext = NULL; | |
80 | ||
81 | /** | |
82 | * Emergency variables. | |
83 | * | |
84 | * These are used when the system is out of resources, and we want to be able | |
85 | * to proceed anyway at least to the point of a controlled shutdown. | |
86 | */ | |
87 | static struct { | |
88 | struct cleanup_entry ce; | |
89 | void *args[20]; | |
90 | ||
91 | /** | |
92 | * Emergency error message buffer. | |
93 | * | |
94 | * The size is estimated using the following heuristic: | |
95 | * - 6x255 For inserted strings (%.255s &c in fmt; and %s with limited | |
96 | * length arg). | |
97 | * - 1x255 For constant text. | |
98 | * - 1x255 For strerror(). | |
99 | * - And the total doubled just in case. | |
100 | */ | |
101 | char errmsg[4096]; | |
102 | } emergency; | |
103 | ||
104 | /** | |
105 | * Default fatal error handler. | |
106 | * | |
107 | * This handler performs all error unwinding for the current context, and | |
108 | * terminates the program with an error exit code. | |
109 | */ | |
110 | void | |
111 | catch_fatal_error(void) | |
112 | { | |
113 | pop_error_context(ehflag_bombout); | |
114 | exit(2); | |
115 | } | |
116 | ||
117 | void | |
118 | print_fatal_error(const char *emsg, const void *data) | |
119 | { | |
120 | fprintf(stderr, "%s%s:%s %s%s:%s %s\n", | |
121 | color_get(COLOR_PROG), dpkg_get_progname(), color_reset(), | |
122 | color_get(COLOR_ERROR), _("error"), color_reset(), emsg); | |
123 | } | |
124 | ||
125 | static void | |
126 | print_abort_error(const char *etype, const char *emsg) | |
127 | { | |
128 | fprintf(stderr, _("%s%s%s: %s%s:%s\n %s\n"), | |
129 | color_get(COLOR_PROG), dpkg_get_progname(), color_reset(), | |
130 | color_get(COLOR_ERROR), etype, color_reset(), emsg); | |
131 | } | |
132 | ||
133 | static struct error_context * | |
134 | error_context_new(void) | |
135 | { | |
136 | struct error_context *necp; | |
137 | ||
138 | necp = malloc(sizeof(struct error_context)); | |
139 | if (!necp) | |
140 | ohshite(_("out of memory for new error context")); | |
141 | necp->next= econtext; | |
142 | necp->cleanups= NULL; | |
143 | necp->errmsg = NULL; | |
144 | econtext= necp; | |
145 | ||
146 | return necp; | |
147 | } | |
148 | ||
149 | static void | |
150 | set_error_printer(struct error_context *ec, error_printer_func *func, | |
151 | const void *data) | |
152 | { | |
153 | ec->printer.func = func; | |
154 | ec->printer.data = data; | |
155 | } | |
156 | ||
157 | static void | |
158 | set_func_handler(struct error_context *ec, error_handler_func *func) | |
159 | { | |
160 | ec->handler_type = HANDLER_TYPE_FUNC; | |
161 | ec->handler.func = func; | |
162 | } | |
163 | ||
164 | static void | |
165 | set_jump_handler(struct error_context *ec, jmp_buf *jump) | |
166 | { | |
167 | ec->handler_type = HANDLER_TYPE_JUMP; | |
168 | ec->handler.jump = jump; | |
169 | } | |
170 | ||
171 | static void | |
172 | error_context_errmsg_free(struct error_context *ec) | |
173 | { | |
174 | if (ec->errmsg != emergency.errmsg) | |
175 | free(ec->errmsg); | |
176 | } | |
177 | ||
178 | static void | |
179 | error_context_errmsg_set(struct error_context *ec, char *errmsg) | |
180 | { | |
181 | error_context_errmsg_free(ec); | |
182 | ec->errmsg = errmsg; | |
183 | } | |
184 | ||
185 | static int DPKG_ATTR_VPRINTF(1) | |
186 | error_context_errmsg_format(const char *fmt, va_list args) | |
187 | { | |
188 | va_list args_copy; | |
189 | char *errmsg = NULL; | |
190 | int rc; | |
191 | ||
192 | va_copy(args_copy, args); | |
193 | rc = vasprintf(&errmsg, fmt, args); | |
194 | va_end(args_copy); | |
195 | ||
196 | /* If the message was constructed successfully, at least we have some | |
197 | * error message, which is better than nothing. */ | |
198 | if (rc >= 0) | |
199 | error_context_errmsg_set(econtext, errmsg); | |
200 | ||
201 | if (rc < 0) { | |
202 | /* If there was any error, just use the emergency error message buffer, | |
203 | * even if it ends up being truncated, at least we will have a big part | |
204 | * of the problem. */ | |
205 | rc = vsnprintf(emergency.errmsg, sizeof(emergency.errmsg), fmt, args); | |
206 | ||
207 | /* Return failure only if we get truncated. */ | |
208 | if (rc >= (int)sizeof(emergency.errmsg)) | |
209 | rc = -1; | |
210 | ||
211 | error_context_errmsg_set(econtext, emergency.errmsg); | |
212 | } | |
213 | ||
214 | return rc; | |
215 | } | |
216 | ||
217 | void | |
218 | push_error_context_func(error_handler_func *handler, | |
219 | error_printer_func *printer, | |
220 | const void *printer_data) | |
221 | { | |
222 | struct error_context *ec; | |
223 | ||
224 | ec = error_context_new(); | |
225 | set_error_printer(ec, printer, printer_data); | |
226 | set_func_handler(ec, handler); | |
227 | onerr_abort = 0; | |
228 | } | |
229 | ||
230 | void | |
231 | push_error_context_jump(jmp_buf *jumper, | |
232 | error_printer_func *printer, | |
233 | const void *printer_data) | |
234 | { | |
235 | struct error_context *ec; | |
236 | ||
237 | ec = error_context_new(); | |
238 | set_error_printer(ec, printer, printer_data); | |
239 | set_jump_handler(ec, jumper); | |
240 | onerr_abort = 0; | |
241 | } | |
242 | ||
243 | void | |
244 | push_error_context(void) | |
245 | { | |
246 | push_error_context_func(catch_fatal_error, print_fatal_error, NULL); | |
247 | } | |
248 | ||
249 | static void | |
250 | print_cleanup_error(const char *emsg, const void *data) | |
251 | { | |
252 | print_abort_error(_("error while cleaning up"), emsg); | |
253 | } | |
254 | ||
255 | static void | |
256 | run_cleanups(struct error_context *econ, int flagsetin) | |
257 | { | |
258 | static volatile int preventrecurse= 0; | |
259 | struct cleanup_entry *volatile cep; | |
260 | struct cleanup_entry *ncep; | |
261 | struct error_context recurserr, *oldecontext; | |
262 | jmp_buf recurse_jump; | |
263 | volatile int i, flagset; | |
264 | ||
265 | if (econ->printer.func) | |
266 | econ->printer.func(econ->errmsg, econ->printer.data); | |
267 | ||
268 | if (++preventrecurse > 3) { | |
269 | onerr_abort++; | |
270 | print_cleanup_error(_("too many nested errors during error recovery"), NULL); | |
271 | flagset= 0; | |
272 | } else { | |
273 | flagset= flagsetin; | |
274 | } | |
275 | cep= econ->cleanups; | |
276 | oldecontext= econtext; | |
277 | while (cep) { | |
278 | for (i=0; i<NCALLS; i++) { | |
279 | if (cep->calls[i].call && cep->calls[i].mask & flagset) { | |
280 | if (setjmp(recurse_jump)) { | |
281 | run_cleanups(&recurserr, ehflag_bombout | ehflag_recursiveerror); | |
282 | } else { | |
283 | memset(&recurserr, 0, sizeof(recurserr)); | |
284 | set_error_printer(&recurserr, print_cleanup_error, NULL); | |
285 | set_jump_handler(&recurserr, &recurse_jump); | |
286 | econtext= &recurserr; | |
287 | cep->calls[i].call(cep->argc,cep->argv); | |
288 | } | |
289 | econtext= oldecontext; | |
290 | } | |
291 | } | |
292 | flagset &= cep->cpmask; | |
293 | flagset |= cep->cpvalue; | |
294 | ncep= cep->next; | |
295 | if (cep != &emergency.ce) free(cep); | |
296 | cep= ncep; | |
297 | } | |
298 | preventrecurse--; | |
299 | } | |
300 | ||
301 | /** | |
302 | * Push an error cleanup checkpoint. | |
303 | * | |
304 | * This will arrange that when pop_error_context() is called, all previous | |
305 | * cleanups will be executed with | |
306 | * flagset = (original_flagset & mask) | value | |
307 | * where original_flagset is the argument to pop_error_context() (as | |
308 | * modified by any checkpoint which was pushed later). | |
309 | */ | |
310 | void push_checkpoint(int mask, int value) { | |
311 | struct cleanup_entry *cep; | |
312 | int i; | |
313 | ||
314 | cep = malloc(sizeof(struct cleanup_entry) + sizeof(char *)); | |
315 | if (cep == NULL) { | |
316 | onerr_abort++; | |
317 | ohshite(_("out of memory for new cleanup entry")); | |
318 | } | |
319 | ||
320 | for (i=0; i<NCALLS; i++) { cep->calls[i].call=NULL; cep->calls[i].mask=0; } | |
321 | cep->cpmask= mask; cep->cpvalue= value; | |
322 | cep->argc= 0; cep->argv[0]= NULL; | |
323 | cep->next= econtext->cleanups; | |
324 | econtext->cleanups= cep; | |
325 | } | |
326 | ||
327 | void push_cleanup(void (*call1)(int argc, void **argv), int mask1, | |
328 | void (*call2)(int argc, void **argv), int mask2, | |
329 | unsigned int nargs, ...) { | |
330 | struct cleanup_entry *cep; | |
331 | void **argv; | |
332 | int e = 0; | |
333 | va_list args; | |
334 | ||
335 | onerr_abort++; | |
336 | ||
337 | cep = malloc(sizeof(struct cleanup_entry) + sizeof(char *) * (nargs + 1)); | |
338 | if (!cep) { | |
339 | if (nargs > array_count(emergency.args)) | |
340 | ohshite(_("out of memory for new cleanup entry with many arguments")); | |
341 | e= errno; cep= &emergency.ce; | |
342 | } | |
343 | cep->calls[0].call= call1; cep->calls[0].mask= mask1; | |
344 | cep->calls[1].call= call2; cep->calls[1].mask= mask2; | |
345 | cep->cpmask=~0; cep->cpvalue=0; cep->argc= nargs; | |
346 | va_start(args, nargs); | |
347 | argv = cep->argv; | |
348 | while (nargs-- > 0) | |
349 | *argv++ = va_arg(args, void *); | |
350 | *argv++ = NULL; | |
351 | va_end(args); | |
352 | cep->next= econtext->cleanups; | |
353 | econtext->cleanups= cep; | |
354 | if (cep == &emergency.ce) { | |
355 | errno = e; | |
356 | ohshite(_("out of memory for new cleanup entry")); | |
357 | } | |
358 | ||
359 | onerr_abort--; | |
360 | } | |
361 | ||
362 | void pop_cleanup(int flagset) { | |
363 | struct cleanup_entry *cep; | |
364 | int i; | |
365 | ||
366 | cep= econtext->cleanups; | |
367 | econtext->cleanups= cep->next; | |
368 | for (i=0; i<NCALLS; i++) { | |
369 | if (cep->calls[i].call && cep->calls[i].mask & flagset) | |
370 | cep->calls[i].call(cep->argc,cep->argv); | |
371 | } | |
372 | if (cep != &emergency.ce) free(cep); | |
373 | } | |
374 | ||
375 | /** | |
376 | * Unwind the current error context by running its registered cleanups. | |
377 | */ | |
378 | void | |
379 | pop_error_context(int flagset) | |
380 | { | |
381 | struct error_context *tecp; | |
382 | ||
383 | tecp = econtext; | |
384 | econtext = tecp->next; | |
385 | ||
386 | /* If we are cleaning up normally, do not print anything. */ | |
387 | if (flagset & ehflag_normaltidy) | |
388 | set_error_printer(tecp, NULL, NULL); | |
389 | run_cleanups(tecp, flagset); | |
390 | ||
391 | error_context_errmsg_free(tecp); | |
392 | free(tecp); | |
393 | } | |
394 | ||
395 | static void DPKG_ATTR_NORET | |
396 | run_error_handler(void) | |
397 | { | |
398 | if (onerr_abort) { | |
399 | /* We arrived here due to a fatal error from which we cannot recover, | |
400 | * and trying to do so would most probably get us here again. That's | |
401 | * why we will not try to do any error unwinding either. We'll just | |
402 | * abort. Hopefully the user can fix the situation (out of disk, out | |
403 | * of memory, etc). */ | |
404 | print_abort_error(_("unrecoverable fatal error, aborting"), econtext->errmsg); | |
405 | exit(2); | |
406 | } | |
407 | ||
408 | if (econtext == NULL) { | |
409 | print_abort_error(_("outside error context, aborting"), econtext->errmsg); | |
410 | exit(2); | |
411 | } else if (econtext->handler_type == HANDLER_TYPE_FUNC) { | |
412 | econtext->handler.func(); | |
413 | internerr("error handler returned unexpectedly!"); | |
414 | } else if (econtext->handler_type == HANDLER_TYPE_JUMP) { | |
415 | longjmp(*econtext->handler.jump, 1); | |
416 | } else { | |
417 | internerr("unknown error handler type %d!", econtext->handler_type); | |
418 | } | |
419 | } | |
420 | ||
421 | void ohshit(const char *fmt, ...) { | |
422 | va_list args; | |
423 | ||
424 | va_start(args, fmt); | |
425 | error_context_errmsg_format(fmt, args); | |
426 | va_end(args); | |
427 | ||
428 | run_error_handler(); | |
429 | } | |
430 | ||
431 | void | |
432 | ohshitv(const char *fmt, va_list args) | |
433 | { | |
434 | error_context_errmsg_format(fmt, args); | |
435 | ||
436 | run_error_handler(); | |
437 | } | |
438 | ||
439 | void ohshite(const char *fmt, ...) { | |
440 | int e, rc; | |
441 | va_list args; | |
442 | ||
443 | e=errno; | |
444 | ||
445 | /* First we construct the formatted message. */ | |
446 | va_start(args, fmt); | |
447 | rc = error_context_errmsg_format(fmt, args); | |
448 | va_end(args); | |
449 | ||
450 | /* Then if there was no error we append the string for errno. Otherwise | |
451 | * we just use the emergency error message buffer, and ignore the errno | |
452 | * value, as we will probably have no space left anyway. */ | |
453 | if (rc > 0) { | |
454 | char *errmsg = NULL; | |
455 | ||
456 | rc = asprintf(&errmsg, "%s: %s", econtext->errmsg, strerror(e)); | |
457 | if (rc > 0) | |
458 | error_context_errmsg_set(econtext, errmsg); | |
459 | } | |
460 | ||
461 | run_error_handler(); | |
462 | } | |
463 | ||
464 | void | |
465 | do_internerr(const char *file, int line, const char *func, const char *fmt, ...) | |
466 | { | |
467 | va_list args; | |
468 | ||
469 | va_start(args, fmt); | |
470 | error_context_errmsg_format(fmt, args); | |
471 | va_end(args); | |
472 | ||
473 | fprintf(stderr, "%s%s:%s:%d:%s:%s %s%s:%s %s\n", color_get(COLOR_PROG), | |
474 | dpkg_get_progname(), file, line, func, color_reset(), | |
475 | color_get(COLOR_ERROR), _("internal error"), color_reset(), | |
476 | econtext->errmsg); | |
477 | ||
478 | abort(); | |
479 | } |