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1 /* pngerror.c - stub functions for i/o and memory allocation | |
2 * | |
3 * Last changed in libpng 1.6.1 [March 28, 2013] | |
4 * Copyright (c) 1998-2013 Glenn Randers-Pehrson | |
5 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) | |
6 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) | |
7 * | |
8 * This code is released under the libpng license. | |
9 * For conditions of distribution and use, see the disclaimer | |
10 * and license in png.h | |
11 * | |
12 * This file provides a location for all error handling. Users who | |
13 * need special error handling are expected to write replacement functions | |
14 * and use png_set_error_fn() to use those functions. See the instructions | |
15 * at each function. | |
16 */ | |
17 | |
18 #include "pngpriv.h" | |
19 | |
20 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
21 | |
22 static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr, | |
23 png_const_charp error_message)),PNG_NORETURN); | |
24 | |
25 #ifdef PNG_WARNINGS_SUPPORTED | |
26 static void /* PRIVATE */ | |
27 png_default_warning PNGARG((png_const_structrp png_ptr, | |
28 png_const_charp warning_message)); | |
29 #endif /* PNG_WARNINGS_SUPPORTED */ | |
30 | |
31 /* This function is called whenever there is a fatal error. This function | |
32 * should not be changed. If there is a need to handle errors differently, | |
33 * you should supply a replacement error function and use png_set_error_fn() | |
34 * to replace the error function at run-time. | |
35 */ | |
36 #ifdef PNG_ERROR_TEXT_SUPPORTED | |
37 PNG_FUNCTION(void,PNGAPI | |
38 png_error,(png_const_structrp png_ptr, png_const_charp error_message), | |
39 PNG_NORETURN) | |
40 { | |
41 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
42 char msg[16]; | |
43 if (png_ptr != NULL) | |
44 { | |
45 if (png_ptr->flags& | |
46 (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) | |
47 { | |
48 if (*error_message == PNG_LITERAL_SHARP) | |
49 { | |
50 /* Strip "#nnnn " from beginning of error message. */ | |
51 int offset; | |
52 for (offset = 1; offset<15; offset++) | |
53 if (error_message[offset] == ' ') | |
54 break; | |
55 | |
56 if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT) | |
57 { | |
58 int i; | |
59 for (i = 0; i < offset - 1; i++) | |
60 msg[i] = error_message[i + 1]; | |
61 msg[i - 1] = '\0'; | |
62 error_message = msg; | |
63 } | |
64 | |
65 else | |
66 error_message += offset; | |
67 } | |
68 | |
69 else | |
70 { | |
71 if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT) | |
72 { | |
73 msg[0] = '0'; | |
74 msg[1] = '\0'; | |
75 error_message = msg; | |
76 } | |
77 } | |
78 } | |
79 } | |
80 #endif | |
81 if (png_ptr != NULL && png_ptr->error_fn != NULL) | |
82 (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), | |
83 error_message); | |
84 | |
85 /* If the custom handler doesn't exist, or if it returns, | |
86 use the default handler, which will not return. */ | |
87 png_default_error(png_ptr, error_message); | |
88 } | |
89 #else | |
90 PNG_FUNCTION(void,PNGAPI | |
91 png_err,(png_const_structrp png_ptr),PNG_NORETURN) | |
92 { | |
93 /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed | |
94 * erroneously as '\0', instead of the empty string "". This was | |
95 * apparently an error, introduced in libpng-1.2.20, and png_default_error | |
96 * will crash in this case. | |
97 */ | |
98 if (png_ptr != NULL && png_ptr->error_fn != NULL) | |
99 (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), ""); | |
100 | |
101 /* If the custom handler doesn't exist, or if it returns, | |
102 use the default handler, which will not return. */ | |
103 png_default_error(png_ptr, ""); | |
104 } | |
105 #endif /* PNG_ERROR_TEXT_SUPPORTED */ | |
106 | |
107 /* Utility to safely appends strings to a buffer. This never errors out so | |
108 * error checking is not required in the caller. | |
109 */ | |
110 size_t | |
111 png_safecat(png_charp buffer, size_t bufsize, size_t pos, | |
112 png_const_charp string) | |
113 { | |
114 if (buffer != NULL && pos < bufsize) | |
115 { | |
116 if (string != NULL) | |
117 while (*string != '\0' && pos < bufsize-1) | |
118 buffer[pos++] = *string++; | |
119 | |
120 buffer[pos] = '\0'; | |
121 } | |
122 | |
123 return pos; | |
124 } | |
125 | |
126 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED) | |
127 /* Utility to dump an unsigned value into a buffer, given a start pointer and | |
128 * and end pointer (which should point just *beyond* the end of the buffer!) | |
129 * Returns the pointer to the start of the formatted string. | |
130 */ | |
131 png_charp | |
132 png_format_number(png_const_charp start, png_charp end, int format, | |
133 png_alloc_size_t number) | |
134 { | |
135 int count = 0; /* number of digits output */ | |
136 int mincount = 1; /* minimum number required */ | |
137 int output = 0; /* digit output (for the fixed point format) */ | |
138 | |
139 *--end = '\0'; | |
140 | |
141 /* This is written so that the loop always runs at least once, even with | |
142 * number zero. | |
143 */ | |
144 while (end > start && (number != 0 || count < mincount)) | |
145 { | |
146 | |
147 static const char digits[] = "0123456789ABCDEF"; | |
148 | |
149 switch (format) | |
150 { | |
151 case PNG_NUMBER_FORMAT_fixed: | |
152 /* Needs five digits (the fraction) */ | |
153 mincount = 5; | |
154 if (output || number % 10 != 0) | |
155 { | |
156 *--end = digits[number % 10]; | |
157 output = 1; | |
158 } | |
159 number /= 10; | |
160 break; | |
161 | |
162 case PNG_NUMBER_FORMAT_02u: | |
163 /* Expects at least 2 digits. */ | |
164 mincount = 2; | |
165 /* FALL THROUGH */ | |
166 | |
167 case PNG_NUMBER_FORMAT_u: | |
168 *--end = digits[number % 10]; | |
169 number /= 10; | |
170 break; | |
171 | |
172 case PNG_NUMBER_FORMAT_02x: | |
173 /* This format expects at least two digits */ | |
174 mincount = 2; | |
175 /* FALL THROUGH */ | |
176 | |
177 case PNG_NUMBER_FORMAT_x: | |
178 *--end = digits[number & 0xf]; | |
179 number >>= 4; | |
180 break; | |
181 | |
182 default: /* an error */ | |
183 number = 0; | |
184 break; | |
185 } | |
186 | |
187 /* Keep track of the number of digits added */ | |
188 ++count; | |
189 | |
190 /* Float a fixed number here: */ | |
191 if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start) | |
192 { | |
193 /* End of the fraction, but maybe nothing was output? In that case | |
194 * drop the decimal point. If the number is a true zero handle that | |
195 * here. | |
196 */ | |
197 if (output) | |
198 *--end = '.'; | |
199 else if (number == 0) /* and !output */ | |
200 *--end = '0'; | |
201 } | |
202 } | |
203 | |
204 return end; | |
205 } | |
206 #endif | |
207 | |
208 #ifdef PNG_WARNINGS_SUPPORTED | |
209 /* This function is called whenever there is a non-fatal error. This function | |
210 * should not be changed. If there is a need to handle warnings differently, | |
211 * you should supply a replacement warning function and use | |
212 * png_set_error_fn() to replace the warning function at run-time. | |
213 */ | |
214 void PNGAPI | |
215 png_warning(png_const_structrp png_ptr, png_const_charp warning_message) | |
216 { | |
217 int offset = 0; | |
218 if (png_ptr != NULL) | |
219 { | |
220 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
221 if (png_ptr->flags& | |
222 (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) | |
223 #endif | |
224 { | |
225 if (*warning_message == PNG_LITERAL_SHARP) | |
226 { | |
227 for (offset = 1; offset < 15; offset++) | |
228 if (warning_message[offset] == ' ') | |
229 break; | |
230 } | |
231 } | |
232 } | |
233 if (png_ptr != NULL && png_ptr->warning_fn != NULL) | |
234 (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr), | |
235 warning_message + offset); | |
236 else | |
237 png_default_warning(png_ptr, warning_message + offset); | |
238 } | |
239 | |
240 /* These functions support 'formatted' warning messages with up to | |
241 * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter | |
242 * is introduced by @<number>, where 'number' starts at 1. This follows the | |
243 * standard established by X/Open for internationalizable error messages. | |
244 */ | |
245 void | |
246 png_warning_parameter(png_warning_parameters p, int number, | |
247 png_const_charp string) | |
248 { | |
249 if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT) | |
250 (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string); | |
251 } | |
252 | |
253 void | |
254 png_warning_parameter_unsigned(png_warning_parameters p, int number, int format, | |
255 png_alloc_size_t value) | |
256 { | |
257 char buffer[PNG_NUMBER_BUFFER_SIZE]; | |
258 png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value)); | |
259 } | |
260 | |
261 void | |
262 png_warning_parameter_signed(png_warning_parameters p, int number, int format, | |
263 png_int_32 value) | |
264 { | |
265 png_alloc_size_t u; | |
266 png_charp str; | |
267 char buffer[PNG_NUMBER_BUFFER_SIZE]; | |
268 | |
269 /* Avoid overflow by doing the negate in a png_alloc_size_t: */ | |
270 u = (png_alloc_size_t)value; | |
271 if (value < 0) | |
272 u = ~u + 1; | |
273 | |
274 str = PNG_FORMAT_NUMBER(buffer, format, u); | |
275 | |
276 if (value < 0 && str > buffer) | |
277 *--str = '-'; | |
278 | |
279 png_warning_parameter(p, number, str); | |
280 } | |
281 | |
282 void | |
283 png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p, | |
284 png_const_charp message) | |
285 { | |
286 /* The internal buffer is just 192 bytes - enough for all our messages, | |
287 * overflow doesn't happen because this code checks! If someone figures | |
288 * out how to send us a message longer than 192 bytes, all that will | |
289 * happen is that the message will be truncated appropriately. | |
290 */ | |
291 size_t i = 0; /* Index in the msg[] buffer: */ | |
292 char msg[192]; | |
293 | |
294 /* Each iteration through the following loop writes at most one character | |
295 * to msg[i++] then returns here to validate that there is still space for | |
296 * the trailing '\0'. It may (in the case of a parameter) read more than | |
297 * one character from message[]; it must check for '\0' and continue to the | |
298 * test if it finds the end of string. | |
299 */ | |
300 while (i<(sizeof msg)-1 && *message != '\0') | |
301 { | |
302 /* '@' at end of string is now just printed (previously it was skipped); | |
303 * it is an error in the calling code to terminate the string with @. | |
304 */ | |
305 if (p != NULL && *message == '@' && message[1] != '\0') | |
306 { | |
307 int parameter_char = *++message; /* Consume the '@' */ | |
308 static const char valid_parameters[] = "123456789"; | |
309 int parameter = 0; | |
310 | |
311 /* Search for the parameter digit, the index in the string is the | |
312 * parameter to use. | |
313 */ | |
314 while (valid_parameters[parameter] != parameter_char && | |
315 valid_parameters[parameter] != '\0') | |
316 ++parameter; | |
317 | |
318 /* If the parameter digit is out of range it will just get printed. */ | |
319 if (parameter < PNG_WARNING_PARAMETER_COUNT) | |
320 { | |
321 /* Append this parameter */ | |
322 png_const_charp parm = p[parameter]; | |
323 png_const_charp pend = p[parameter] + (sizeof p[parameter]); | |
324 | |
325 /* No need to copy the trailing '\0' here, but there is no guarantee | |
326 * that parm[] has been initialized, so there is no guarantee of a | |
327 * trailing '\0': | |
328 */ | |
329 while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend) | |
330 msg[i++] = *parm++; | |
331 | |
332 /* Consume the parameter digit too: */ | |
333 ++message; | |
334 continue; | |
335 } | |
336 | |
337 /* else not a parameter and there is a character after the @ sign; just | |
338 * copy that. This is known not to be '\0' because of the test above. | |
339 */ | |
340 } | |
341 | |
342 /* At this point *message can't be '\0', even in the bad parameter case | |
343 * above where there is a lone '@' at the end of the message string. | |
344 */ | |
345 msg[i++] = *message++; | |
346 } | |
347 | |
348 /* i is always less than (sizeof msg), so: */ | |
349 msg[i] = '\0'; | |
350 | |
351 /* And this is the formatted message. It may be larger than | |
352 * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these | |
353 * are not (currently) formatted. | |
354 */ | |
355 png_warning(png_ptr, msg); | |
356 } | |
357 #endif /* PNG_WARNINGS_SUPPORTED */ | |
358 | |
359 #ifdef PNG_BENIGN_ERRORS_SUPPORTED | |
360 void PNGAPI | |
361 png_benign_error(png_const_structrp png_ptr, png_const_charp error_message) | |
362 { | |
363 if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) | |
364 { | |
365 # ifdef PNG_READ_SUPPORTED | |
366 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
367 png_ptr->chunk_name != 0) | |
368 png_chunk_warning(png_ptr, error_message); | |
369 else | |
370 # endif | |
371 png_warning(png_ptr, error_message); | |
372 } | |
373 | |
374 else | |
375 { | |
376 # ifdef PNG_READ_SUPPORTED | |
377 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
378 png_ptr->chunk_name != 0) | |
379 png_chunk_error(png_ptr, error_message); | |
380 else | |
381 # endif | |
382 png_error(png_ptr, error_message); | |
383 } | |
384 } | |
385 | |
386 void /* PRIVATE */ | |
387 png_app_warning(png_const_structrp png_ptr, png_const_charp error_message) | |
388 { | |
389 if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) | |
390 png_warning(png_ptr, error_message); | |
391 else | |
392 png_error(png_ptr, error_message); | |
393 } | |
394 | |
395 void /* PRIVATE */ | |
396 png_app_error(png_const_structrp png_ptr, png_const_charp error_message) | |
397 { | |
398 if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) | |
399 png_warning(png_ptr, error_message); | |
400 else | |
401 png_error(png_ptr, error_message); | |
402 } | |
403 #endif /* BENIGN_ERRORS */ | |
404 | |
405 /* These utilities are used internally to build an error message that relates | |
406 * to the current chunk. The chunk name comes from png_ptr->chunk_name, | |
407 * this is used to prefix the message. The message is limited in length | |
408 * to 63 bytes, the name characters are output as hex digits wrapped in [] | |
409 * if the character is invalid. | |
410 */ | |
411 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) | |
412 static PNG_CONST char png_digit[16] = { | |
413 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', | |
414 'A', 'B', 'C', 'D', 'E', 'F' | |
415 }; | |
416 | |
417 #define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */ | |
418 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED) | |
419 static void /* PRIVATE */ | |
420 png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp | |
421 error_message) | |
422 { | |
423 png_uint_32 chunk_name = png_ptr->chunk_name; | |
424 int iout = 0, ishift = 24; | |
425 | |
426 while (ishift >= 0) | |
427 { | |
428 int c = (int)(chunk_name >> ishift) & 0xff; | |
429 | |
430 ishift -= 8; | |
431 if (isnonalpha(c)) | |
432 { | |
433 buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET; | |
434 buffer[iout++] = png_digit[(c & 0xf0) >> 4]; | |
435 buffer[iout++] = png_digit[c & 0x0f]; | |
436 buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET; | |
437 } | |
438 | |
439 else | |
440 { | |
441 buffer[iout++] = (char)c; | |
442 } | |
443 } | |
444 | |
445 if (error_message == NULL) | |
446 buffer[iout] = '\0'; | |
447 | |
448 else | |
449 { | |
450 int iin = 0; | |
451 | |
452 buffer[iout++] = ':'; | |
453 buffer[iout++] = ' '; | |
454 | |
455 while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0') | |
456 buffer[iout++] = error_message[iin++]; | |
457 | |
458 /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */ | |
459 buffer[iout] = '\0'; | |
460 } | |
461 } | |
462 #endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */ | |
463 | |
464 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED) | |
465 PNG_FUNCTION(void,PNGAPI | |
466 png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message), | |
467 PNG_NORETURN) | |
468 { | |
469 char msg[18+PNG_MAX_ERROR_TEXT]; | |
470 if (png_ptr == NULL) | |
471 png_error(png_ptr, error_message); | |
472 | |
473 else | |
474 { | |
475 png_format_buffer(png_ptr, msg, error_message); | |
476 png_error(png_ptr, msg); | |
477 } | |
478 } | |
479 #endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */ | |
480 | |
481 #ifdef PNG_WARNINGS_SUPPORTED | |
482 void PNGAPI | |
483 png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message) | |
484 { | |
485 char msg[18+PNG_MAX_ERROR_TEXT]; | |
486 if (png_ptr == NULL) | |
487 png_warning(png_ptr, warning_message); | |
488 | |
489 else | |
490 { | |
491 png_format_buffer(png_ptr, msg, warning_message); | |
492 png_warning(png_ptr, msg); | |
493 } | |
494 } | |
495 #endif /* PNG_WARNINGS_SUPPORTED */ | |
496 | |
497 #ifdef PNG_READ_SUPPORTED | |
498 #ifdef PNG_BENIGN_ERRORS_SUPPORTED | |
499 void PNGAPI | |
500 png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp | |
501 error_message) | |
502 { | |
503 if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) | |
504 png_chunk_warning(png_ptr, error_message); | |
505 | |
506 else | |
507 png_chunk_error(png_ptr, error_message); | |
508 } | |
509 #endif | |
510 #endif /* PNG_READ_SUPPORTED */ | |
511 | |
512 void /* PRIVATE */ | |
513 png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error) | |
514 { | |
515 /* This is always supported, but for just read or just write it | |
516 * unconditionally does the right thing. | |
517 */ | |
518 # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) | |
519 if (png_ptr->mode & PNG_IS_READ_STRUCT) | |
520 # endif | |
521 | |
522 # ifdef PNG_READ_SUPPORTED | |
523 { | |
524 if (error < PNG_CHUNK_ERROR) | |
525 png_chunk_warning(png_ptr, message); | |
526 | |
527 else | |
528 png_chunk_benign_error(png_ptr, message); | |
529 } | |
530 # endif | |
531 | |
532 # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) | |
533 else if (!(png_ptr->mode & PNG_IS_READ_STRUCT)) | |
534 # endif | |
535 | |
536 # ifdef PNG_WRITE_SUPPORTED | |
537 { | |
538 if (error < PNG_CHUNK_WRITE_ERROR) | |
539 png_app_warning(png_ptr, message); | |
540 | |
541 else | |
542 png_app_error(png_ptr, message); | |
543 } | |
544 # endif | |
545 } | |
546 | |
547 #ifdef PNG_ERROR_TEXT_SUPPORTED | |
548 #ifdef PNG_FLOATING_POINT_SUPPORTED | |
549 PNG_FUNCTION(void, | |
550 png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN) | |
551 { | |
552 # define fixed_message "fixed point overflow in " | |
553 # define fixed_message_ln ((sizeof fixed_message)-1) | |
554 int iin; | |
555 char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT]; | |
556 memcpy(msg, fixed_message, fixed_message_ln); | |
557 iin = 0; | |
558 if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0) | |
559 { | |
560 msg[fixed_message_ln + iin] = name[iin]; | |
561 ++iin; | |
562 } | |
563 msg[fixed_message_ln + iin] = 0; | |
564 png_error(png_ptr, msg); | |
565 } | |
566 #endif | |
567 #endif | |
568 | |
569 #ifdef PNG_SETJMP_SUPPORTED | |
570 /* This API only exists if ANSI-C style error handling is used, | |
571 * otherwise it is necessary for png_default_error to be overridden. | |
572 */ | |
573 jmp_buf* PNGAPI | |
574 png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn, | |
575 size_t jmp_buf_size) | |
576 { | |
577 /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value | |
578 * and it must not change after that. Libpng doesn't care how big the | |
579 * buffer is, just that it doesn't change. | |
580 * | |
581 * If the buffer size is no *larger* than the size of jmp_buf when libpng is | |
582 * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0 | |
583 * semantics that this call will not fail. If the size is larger, however, | |
584 * the buffer is allocated and this may fail, causing the function to return | |
585 * NULL. | |
586 */ | |
587 if (png_ptr == NULL) | |
588 return NULL; | |
589 | |
590 if (png_ptr->jmp_buf_ptr == NULL) | |
591 { | |
592 png_ptr->jmp_buf_size = 0; /* not allocated */ | |
593 | |
594 if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local)) | |
595 png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; | |
596 | |
597 else | |
598 { | |
599 png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *, | |
600 png_malloc_warn(png_ptr, jmp_buf_size)); | |
601 | |
602 if (png_ptr->jmp_buf_ptr == NULL) | |
603 return NULL; /* new NULL return on OOM */ | |
604 | |
605 png_ptr->jmp_buf_size = jmp_buf_size; | |
606 } | |
607 } | |
608 | |
609 else /* Already allocated: check the size */ | |
610 { | |
611 size_t size = png_ptr->jmp_buf_size; | |
612 | |
613 if (size == 0) | |
614 { | |
615 size = (sizeof png_ptr->jmp_buf_local); | |
616 if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local) | |
617 { | |
618 /* This is an internal error in libpng: somehow we have been left | |
619 * with a stack allocated jmp_buf when the application regained | |
620 * control. It's always possible to fix this up, but for the moment | |
621 * this is a png_error because that makes it easy to detect. | |
622 */ | |
623 png_error(png_ptr, "Libpng jmp_buf still allocated"); | |
624 /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */ | |
625 } | |
626 } | |
627 | |
628 if (size != jmp_buf_size) | |
629 { | |
630 png_warning(png_ptr, "Application jmp_buf size changed"); | |
631 return NULL; /* caller will probably crash: no choice here */ | |
632 } | |
633 } | |
634 | |
635 /* Finally fill in the function, now we have a satisfactory buffer. It is | |
636 * valid to change the function on every call. | |
637 */ | |
638 png_ptr->longjmp_fn = longjmp_fn; | |
639 return png_ptr->jmp_buf_ptr; | |
640 } | |
641 | |
642 void /* PRIVATE */ | |
643 png_free_jmpbuf(png_structrp png_ptr) | |
644 { | |
645 if (png_ptr != NULL) | |
646 { | |
647 jmp_buf *jb = png_ptr->jmp_buf_ptr; | |
648 | |
649 /* A size of 0 is used to indicate a local, stack, allocation of the | |
650 * pointer; used here and in png.c | |
651 */ | |
652 if (jb != NULL && png_ptr->jmp_buf_size > 0) | |
653 { | |
654 | |
655 /* This stuff is so that a failure to free the error control structure | |
656 * does not leave libpng in a state with no valid error handling: the | |
657 * free always succeeds, if there is an error it gets ignored. | |
658 */ | |
659 if (jb != &png_ptr->jmp_buf_local) | |
660 { | |
661 /* Make an internal, libpng, jmp_buf to return here */ | |
662 jmp_buf free_jmp_buf; | |
663 | |
664 if (!setjmp(free_jmp_buf)) | |
665 { | |
666 png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */ | |
667 png_ptr->jmp_buf_size = 0; /* stack allocation */ | |
668 png_ptr->longjmp_fn = longjmp; | |
669 png_free(png_ptr, jb); /* Return to setjmp on error */ | |
670 } | |
671 } | |
672 } | |
673 | |
674 /* *Always* cancel everything out: */ | |
675 png_ptr->jmp_buf_size = 0; | |
676 png_ptr->jmp_buf_ptr = NULL; | |
677 png_ptr->longjmp_fn = 0; | |
678 } | |
679 } | |
680 #endif | |
681 | |
682 /* This is the default error handling function. Note that replacements for | |
683 * this function MUST NOT RETURN, or the program will likely crash. This | |
684 * function is used by default, or if the program supplies NULL for the | |
685 * error function pointer in png_set_error_fn(). | |
686 */ | |
687 static PNG_FUNCTION(void /* PRIVATE */, | |
688 png_default_error,(png_const_structrp png_ptr, png_const_charp error_message), | |
689 PNG_NORETURN) | |
690 { | |
691 #ifdef PNG_CONSOLE_IO_SUPPORTED | |
692 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
693 /* Check on NULL only added in 1.5.4 */ | |
694 if (error_message != NULL && *error_message == PNG_LITERAL_SHARP) | |
695 { | |
696 /* Strip "#nnnn " from beginning of error message. */ | |
697 int offset; | |
698 char error_number[16]; | |
699 for (offset = 0; offset<15; offset++) | |
700 { | |
701 error_number[offset] = error_message[offset + 1]; | |
702 if (error_message[offset] == ' ') | |
703 break; | |
704 } | |
705 | |
706 if ((offset > 1) && (offset < 15)) | |
707 { | |
708 error_number[offset - 1] = '\0'; | |
709 fprintf(stderr, "libpng error no. %s: %s", | |
710 error_number, error_message + offset + 1); | |
711 fprintf(stderr, PNG_STRING_NEWLINE); | |
712 } | |
713 | |
714 else | |
715 { | |
716 fprintf(stderr, "libpng error: %s, offset=%d", | |
717 error_message, offset); | |
718 fprintf(stderr, PNG_STRING_NEWLINE); | |
719 } | |
720 } | |
721 else | |
722 #endif | |
723 { | |
724 fprintf(stderr, "libpng error: %s", error_message ? error_message : | |
725 "undefined"); | |
726 fprintf(stderr, PNG_STRING_NEWLINE); | |
727 } | |
728 #else | |
729 PNG_UNUSED(error_message) /* Make compiler happy */ | |
730 #endif | |
731 png_longjmp(png_ptr, 1); | |
732 } | |
733 | |
734 PNG_FUNCTION(void,PNGAPI | |
735 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN) | |
736 { | |
737 #ifdef PNG_SETJMP_SUPPORTED | |
738 if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr) | |
739 png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val); | |
740 #endif | |
741 | |
742 /* Here if not setjmp support or if png_ptr is null. */ | |
743 PNG_ABORT(); | |
744 } | |
745 | |
746 #ifdef PNG_WARNINGS_SUPPORTED | |
747 /* This function is called when there is a warning, but the library thinks | |
748 * it can continue anyway. Replacement functions don't have to do anything | |
749 * here if you don't want them to. In the default configuration, png_ptr is | |
750 * not used, but it is passed in case it may be useful. | |
751 */ | |
752 static void /* PRIVATE */ | |
753 png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message) | |
754 { | |
755 #ifdef PNG_CONSOLE_IO_SUPPORTED | |
756 # ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
757 if (*warning_message == PNG_LITERAL_SHARP) | |
758 { | |
759 int offset; | |
760 char warning_number[16]; | |
761 for (offset = 0; offset < 15; offset++) | |
762 { | |
763 warning_number[offset] = warning_message[offset + 1]; | |
764 if (warning_message[offset] == ' ') | |
765 break; | |
766 } | |
767 | |
768 if ((offset > 1) && (offset < 15)) | |
769 { | |
770 warning_number[offset + 1] = '\0'; | |
771 fprintf(stderr, "libpng warning no. %s: %s", | |
772 warning_number, warning_message + offset); | |
773 fprintf(stderr, PNG_STRING_NEWLINE); | |
774 } | |
775 | |
776 else | |
777 { | |
778 fprintf(stderr, "libpng warning: %s", | |
779 warning_message); | |
780 fprintf(stderr, PNG_STRING_NEWLINE); | |
781 } | |
782 } | |
783 else | |
784 # endif | |
785 | |
786 { | |
787 fprintf(stderr, "libpng warning: %s", warning_message); | |
788 fprintf(stderr, PNG_STRING_NEWLINE); | |
789 } | |
790 #else | |
791 PNG_UNUSED(warning_message) /* Make compiler happy */ | |
792 #endif | |
793 PNG_UNUSED(png_ptr) /* Make compiler happy */ | |
794 } | |
795 #endif /* PNG_WARNINGS_SUPPORTED */ | |
796 | |
797 /* This function is called when the application wants to use another method | |
798 * of handling errors and warnings. Note that the error function MUST NOT | |
799 * return to the calling routine or serious problems will occur. The return | |
800 * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1) | |
801 */ | |
802 void PNGAPI | |
803 png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr, | |
804 png_error_ptr error_fn, png_error_ptr warning_fn) | |
805 { | |
806 if (png_ptr == NULL) | |
807 return; | |
808 | |
809 png_ptr->error_ptr = error_ptr; | |
810 png_ptr->error_fn = error_fn; | |
811 #ifdef PNG_WARNINGS_SUPPORTED | |
812 png_ptr->warning_fn = warning_fn; | |
813 #else | |
814 PNG_UNUSED(warning_fn) | |
815 #endif | |
816 } | |
817 | |
818 | |
819 /* This function returns a pointer to the error_ptr associated with the user | |
820 * functions. The application should free any memory associated with this | |
821 * pointer before png_write_destroy and png_read_destroy are called. | |
822 */ | |
823 png_voidp PNGAPI | |
824 png_get_error_ptr(png_const_structrp png_ptr) | |
825 { | |
826 if (png_ptr == NULL) | |
827 return NULL; | |
828 | |
829 return ((png_voidp)png_ptr->error_ptr); | |
830 } | |
831 | |
832 | |
833 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
834 void PNGAPI | |
835 png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode) | |
836 { | |
837 if (png_ptr != NULL) | |
838 { | |
839 png_ptr->flags &= | |
840 ((~(PNG_FLAG_STRIP_ERROR_NUMBERS | | |
841 PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode); | |
842 } | |
843 } | |
844 #endif | |
845 | |
846 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ | |
847 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) | |
848 /* Currently the above both depend on SETJMP_SUPPORTED, however it would be | |
849 * possible to implement without setjmp support just so long as there is some | |
850 * way to handle the error return here: | |
851 */ | |
852 PNG_FUNCTION(void /* PRIVATE */, | |
853 png_safe_error,(png_structp png_nonconst_ptr, png_const_charp error_message), | |
854 PNG_NORETURN) | |
855 { | |
856 const png_const_structrp png_ptr = png_nonconst_ptr; | |
857 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); | |
858 | |
859 /* An error is always logged here, overwriting anything (typically a warning) | |
860 * that is already there: | |
861 */ | |
862 if (image != NULL) | |
863 { | |
864 png_safecat(image->message, (sizeof image->message), 0, error_message); | |
865 image->warning_or_error |= PNG_IMAGE_ERROR; | |
866 | |
867 /* Retrieve the jmp_buf from within the png_control, making this work for | |
868 * C++ compilation too is pretty tricky: C++ wants a pointer to the first | |
869 * element of a jmp_buf, but C doesn't tell us the type of that. | |
870 */ | |
871 if (image->opaque != NULL && image->opaque->error_buf != NULL) | |
872 longjmp(png_control_jmp_buf(image->opaque), 1); | |
873 | |
874 /* Missing longjmp buffer, the following is to help debugging: */ | |
875 { | |
876 size_t pos = png_safecat(image->message, (sizeof image->message), 0, | |
877 "bad longjmp: "); | |
878 png_safecat(image->message, (sizeof image->message), pos, | |
879 error_message); | |
880 } | |
881 } | |
882 | |
883 /* Here on an internal programming error. */ | |
884 abort(); | |
885 } | |
886 | |
887 #ifdef PNG_WARNINGS_SUPPORTED | |
888 void /* PRIVATE */ | |
889 png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message) | |
890 { | |
891 const png_const_structrp png_ptr = png_nonconst_ptr; | |
892 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); | |
893 | |
894 /* A warning is only logged if there is no prior warning or error. */ | |
895 if (image->warning_or_error == 0) | |
896 { | |
897 png_safecat(image->message, (sizeof image->message), 0, warning_message); | |
898 image->warning_or_error |= PNG_IMAGE_WARNING; | |
899 } | |
900 } | |
901 #endif | |
902 | |
903 int /* PRIVATE */ | |
904 png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg) | |
905 { | |
906 volatile png_imagep image = image_in; | |
907 volatile int result; | |
908 volatile png_voidp saved_error_buf; | |
909 jmp_buf safe_jmpbuf; | |
910 | |
911 /* Safely execute function(arg) with png_error returning to this function. */ | |
912 saved_error_buf = image->opaque->error_buf; | |
913 result = setjmp(safe_jmpbuf) == 0; | |
914 | |
915 if (result) | |
916 { | |
917 | |
918 image->opaque->error_buf = safe_jmpbuf; | |
919 result = function(arg); | |
920 } | |
921 | |
922 image->opaque->error_buf = saved_error_buf; | |
923 | |
924 /* And do the cleanup prior to any failure return. */ | |
925 if (!result) | |
926 png_image_free(image); | |
927 | |
928 return result; | |
929 } | |
930 #endif /* SIMPLIFIED READ/WRITE */ | |
931 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ | |
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