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1 | |
2 /* pngerror.c - stub functions for i/o and memory allocation | |
3 * | |
4 * Last changed in libpng 1.6.15 [November 20, 2014] | |
5 * Copyright (c) 1998-2014 Glenn Randers-Pehrson | |
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) | |
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) | |
8 * | |
9 * This code is released under the libpng license. | |
10 * For conditions of distribution and use, see the disclaimer | |
11 * and license in png.h | |
12 * | |
13 * This file provides a location for all error handling. Users who | |
14 * need special error handling are expected to write replacement functions | |
15 * and use png_set_error_fn() to use those functions. See the instructions | |
16 * at each function. | |
17 */ | |
18 | |
19 #include "pngpriv.h" | |
20 | |
21 #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) | |
22 | |
23 static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr, | |
24 png_const_charp error_message)),PNG_NORETURN); | |
25 | |
26 #ifdef PNG_WARNINGS_SUPPORTED | |
27 static void /* PRIVATE */ | |
28 png_default_warning PNGARG((png_const_structrp png_ptr, | |
29 png_const_charp warning_message)); | |
30 #endif /* WARNINGS */ | |
31 | |
32 /* This function is called whenever there is a fatal error. This function | |
33 * should not be changed. If there is a need to handle errors differently, | |
34 * you should supply a replacement error function and use png_set_error_fn() | |
35 * to replace the error function at run-time. | |
36 */ | |
37 #ifdef PNG_ERROR_TEXT_SUPPORTED | |
38 PNG_FUNCTION(void,PNGAPI | |
39 png_error,(png_const_structrp png_ptr, png_const_charp error_message), | |
40 PNG_NORETURN) | |
41 { | |
42 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
43 char msg[16]; | |
44 if (png_ptr != NULL) | |
45 { | |
46 if ((png_ptr->flags & | |
47 (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0 | |
48 { | |
49 if (*error_message == PNG_LITERAL_SHARP) | |
50 { | |
51 /* Strip "#nnnn " from beginning of error message. */ | |
52 int offset; | |
53 for (offset = 1; offset<15; offset++) | |
54 if (error_message[offset] == ' ') | |
55 break; | |
56 | |
57 if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0) | |
58 { | |
59 int i; | |
60 for (i = 0; i < offset - 1; i++) | |
61 msg[i] = error_message[i + 1]; | |
62 msg[i - 1] = '\0'; | |
63 error_message = msg; | |
64 } | |
65 | |
66 else | |
67 error_message += offset; | |
68 } | |
69 | |
70 else | |
71 { | |
72 if ((png_ptr->flags & PNG_FLAG_STRIP_ERROR_TEXT) != 0) | |
73 { | |
74 msg[0] = '0'; | |
75 msg[1] = '\0'; | |
76 error_message = msg; | |
77 } | |
78 } | |
79 } | |
80 } | |
81 #endif | |
82 if (png_ptr != NULL && png_ptr->error_fn != NULL) | |
83 (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), | |
84 error_message); | |
85 | |
86 /* If the custom handler doesn't exist, or if it returns, | |
87 use the default handler, which will not return. */ | |
88 png_default_error(png_ptr, error_message); | |
89 } | |
90 #else | |
91 PNG_FUNCTION(void,PNGAPI | |
92 png_err,(png_const_structrp png_ptr),PNG_NORETURN) | |
93 { | |
94 /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed | |
95 * erroneously as '\0', instead of the empty string "". This was | |
96 * apparently an error, introduced in libpng-1.2.20, and png_default_error | |
97 * will crash in this case. | |
98 */ | |
99 if (png_ptr != NULL && png_ptr->error_fn != NULL) | |
100 (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), ""); | |
101 | |
102 /* If the custom handler doesn't exist, or if it returns, | |
103 use the default handler, which will not return. */ | |
104 png_default_error(png_ptr, ""); | |
105 } | |
106 #endif /* ERROR_TEXT */ | |
107 | |
108 /* Utility to safely appends strings to a buffer. This never errors out so | |
109 * error checking is not required in the caller. | |
110 */ | |
111 size_t | |
112 png_safecat(png_charp buffer, size_t bufsize, size_t pos, | |
113 png_const_charp string) | |
114 { | |
115 if (buffer != NULL && pos < bufsize) | |
116 { | |
117 if (string != NULL) | |
118 while (*string != '\0' && pos < bufsize-1) | |
119 buffer[pos++] = *string++; | |
120 | |
121 buffer[pos] = '\0'; | |
122 } | |
123 | |
124 return pos; | |
125 } | |
126 | |
127 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED) | |
128 /* Utility to dump an unsigned value into a buffer, given a start pointer and | |
129 * and end pointer (which should point just *beyond* the end of the buffer!) | |
130 * Returns the pointer to the start of the formatted string. | |
131 */ | |
132 png_charp | |
133 png_format_number(png_const_charp start, png_charp end, int format, | |
134 png_alloc_size_t number) | |
135 { | |
136 int count = 0; /* number of digits output */ | |
137 int mincount = 1; /* minimum number required */ | |
138 int output = 0; /* digit output (for the fixed point format) */ | |
139 | |
140 *--end = '\0'; | |
141 | |
142 /* This is written so that the loop always runs at least once, even with | |
143 * number zero. | |
144 */ | |
145 while (end > start && (number != 0 || count < mincount)) | |
146 { | |
147 | |
148 static const char digits[] = "0123456789ABCDEF"; | |
149 | |
150 switch (format) | |
151 { | |
152 case PNG_NUMBER_FORMAT_fixed: | |
153 /* Needs five digits (the fraction) */ | |
154 mincount = 5; | |
155 if (output != 0 || number % 10 != 0) | |
156 { | |
157 *--end = digits[number % 10]; | |
158 output = 1; | |
159 } | |
160 number /= 10; | |
161 break; | |
162 | |
163 case PNG_NUMBER_FORMAT_02u: | |
164 /* Expects at least 2 digits. */ | |
165 mincount = 2; | |
166 /* FALL THROUGH */ | |
167 | |
168 case PNG_NUMBER_FORMAT_u: | |
169 *--end = digits[number % 10]; | |
170 number /= 10; | |
171 break; | |
172 | |
173 case PNG_NUMBER_FORMAT_02x: | |
174 /* This format expects at least two digits */ | |
175 mincount = 2; | |
176 /* FALL THROUGH */ | |
177 | |
178 case PNG_NUMBER_FORMAT_x: | |
179 *--end = digits[number & 0xf]; | |
180 number >>= 4; | |
181 break; | |
182 | |
183 default: /* an error */ | |
184 number = 0; | |
185 break; | |
186 } | |
187 | |
188 /* Keep track of the number of digits added */ | |
189 ++count; | |
190 | |
191 /* Float a fixed number here: */ | |
192 if ((format == PNG_NUMBER_FORMAT_fixed) && (count == 5) && (end > start)) | |
193 { | |
194 /* End of the fraction, but maybe nothing was output? In that case | |
195 * drop the decimal point. If the number is a true zero handle that | |
196 * here. | |
197 */ | |
198 if (output != 0) | |
199 *--end = '.'; | |
200 else if (number == 0) /* and !output */ | |
201 *--end = '0'; | |
202 } | |
203 } | |
204 | |
205 return end; | |
206 } | |
207 #endif | |
208 | |
209 #ifdef PNG_WARNINGS_SUPPORTED | |
210 /* This function is called whenever there is a non-fatal error. This function | |
211 * should not be changed. If there is a need to handle warnings differently, | |
212 * you should supply a replacement warning function and use | |
213 * png_set_error_fn() to replace the warning function at run-time. | |
214 */ | |
215 void PNGAPI | |
216 png_warning(png_const_structrp png_ptr, png_const_charp warning_message) | |
217 { | |
218 int offset = 0; | |
219 if (png_ptr != NULL) | |
220 { | |
221 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
222 if ((png_ptr->flags & | |
223 (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) != 0) | |
224 #endif | |
225 { | |
226 if (*warning_message == PNG_LITERAL_SHARP) | |
227 { | |
228 for (offset = 1; offset < 15; offset++) | |
229 if (warning_message[offset] == ' ') | |
230 break; | |
231 } | |
232 } | |
233 } | |
234 if (png_ptr != NULL && png_ptr->warning_fn != NULL) | |
235 (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr), | |
236 warning_message + offset); | |
237 else | |
238 png_default_warning(png_ptr, warning_message + offset); | |
239 } | |
240 | |
241 /* These functions support 'formatted' warning messages with up to | |
242 * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter | |
243 * is introduced by @<number>, where 'number' starts at 1. This follows the | |
244 * standard established by X/Open for internationalizable error messages. | |
245 */ | |
246 void | |
247 png_warning_parameter(png_warning_parameters p, int number, | |
248 png_const_charp string) | |
249 { | |
250 if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT) | |
251 (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string); | |
252 } | |
253 | |
254 void | |
255 png_warning_parameter_unsigned(png_warning_parameters p, int number, int format, | |
256 png_alloc_size_t value) | |
257 { | |
258 char buffer[PNG_NUMBER_BUFFER_SIZE]; | |
259 png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value)); | |
260 } | |
261 | |
262 void | |
263 png_warning_parameter_signed(png_warning_parameters p, int number, int format, | |
264 png_int_32 value) | |
265 { | |
266 png_alloc_size_t u; | |
267 png_charp str; | |
268 char buffer[PNG_NUMBER_BUFFER_SIZE]; | |
269 | |
270 /* Avoid overflow by doing the negate in a png_alloc_size_t: */ | |
271 u = (png_alloc_size_t)value; | |
272 if (value < 0) | |
273 u = ~u + 1; | |
274 | |
275 str = PNG_FORMAT_NUMBER(buffer, format, u); | |
276 | |
277 if (value < 0 && str > buffer) | |
278 *--str = '-'; | |
279 | |
280 png_warning_parameter(p, number, str); | |
281 } | |
282 | |
283 void | |
284 png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p, | |
285 png_const_charp message) | |
286 { | |
287 /* The internal buffer is just 192 bytes - enough for all our messages, | |
288 * overflow doesn't happen because this code checks! If someone figures | |
289 * out how to send us a message longer than 192 bytes, all that will | |
290 * happen is that the message will be truncated appropriately. | |
291 */ | |
292 size_t i = 0; /* Index in the msg[] buffer: */ | |
293 char msg[192]; | |
294 | |
295 /* Each iteration through the following loop writes at most one character | |
296 * to msg[i++] then returns here to validate that there is still space for | |
297 * the trailing '\0'. It may (in the case of a parameter) read more than | |
298 * one character from message[]; it must check for '\0' and continue to the | |
299 * test if it finds the end of string. | |
300 */ | |
301 while (i<(sizeof msg)-1 && *message != '\0') | |
302 { | |
303 /* '@' at end of string is now just printed (previously it was skipped); | |
304 * it is an error in the calling code to terminate the string with @. | |
305 */ | |
306 if (p != NULL && *message == '@' && message[1] != '\0') | |
307 { | |
308 int parameter_char = *++message; /* Consume the '@' */ | |
309 static const char valid_parameters[] = "123456789"; | |
310 int parameter = 0; | |
311 | |
312 /* Search for the parameter digit, the index in the string is the | |
313 * parameter to use. | |
314 */ | |
315 while (valid_parameters[parameter] != parameter_char && | |
316 valid_parameters[parameter] != '\0') | |
317 ++parameter; | |
318 | |
319 /* If the parameter digit is out of range it will just get printed. */ | |
320 if (parameter < PNG_WARNING_PARAMETER_COUNT) | |
321 { | |
322 /* Append this parameter */ | |
323 png_const_charp parm = p[parameter]; | |
324 png_const_charp pend = p[parameter] + (sizeof p[parameter]); | |
325 | |
326 /* No need to copy the trailing '\0' here, but there is no guarantee | |
327 * that parm[] has been initialized, so there is no guarantee of a | |
328 * trailing '\0': | |
329 */ | |
330 while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend) | |
331 msg[i++] = *parm++; | |
332 | |
333 /* Consume the parameter digit too: */ | |
334 ++message; | |
335 continue; | |
336 } | |
337 | |
338 /* else not a parameter and there is a character after the @ sign; just | |
339 * copy that. This is known not to be '\0' because of the test above. | |
340 */ | |
341 } | |
342 | |
343 /* At this point *message can't be '\0', even in the bad parameter case | |
344 * above where there is a lone '@' at the end of the message string. | |
345 */ | |
346 msg[i++] = *message++; | |
347 } | |
348 | |
349 /* i is always less than (sizeof msg), so: */ | |
350 msg[i] = '\0'; | |
351 | |
352 /* And this is the formatted message. It may be larger than | |
353 * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these | |
354 * are not (currently) formatted. | |
355 */ | |
356 png_warning(png_ptr, msg); | |
357 } | |
358 #endif /* WARNINGS */ | |
359 | |
360 #ifdef PNG_BENIGN_ERRORS_SUPPORTED | |
361 void PNGAPI | |
362 png_benign_error(png_const_structrp png_ptr, png_const_charp error_message) | |
363 { | |
364 if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0) | |
365 { | |
366 # ifdef PNG_READ_SUPPORTED | |
367 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
368 png_ptr->chunk_name != 0) | |
369 png_chunk_warning(png_ptr, error_message); | |
370 else | |
371 # endif | |
372 png_warning(png_ptr, error_message); | |
373 } | |
374 | |
375 else | |
376 { | |
377 # ifdef PNG_READ_SUPPORTED | |
378 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && | |
379 png_ptr->chunk_name != 0) | |
380 png_chunk_error(png_ptr, error_message); | |
381 else | |
382 # endif | |
383 png_error(png_ptr, error_message); | |
384 } | |
385 | |
386 # ifndef PNG_ERROR_TEXT_SUPPORTED | |
387 PNG_UNUSED(error_message) | |
388 # endif | |
389 } | |
390 | |
391 void /* PRIVATE */ | |
392 png_app_warning(png_const_structrp png_ptr, png_const_charp error_message) | |
393 { | |
394 if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0) | |
395 png_warning(png_ptr, error_message); | |
396 else | |
397 png_error(png_ptr, error_message); | |
398 | |
399 # ifndef PNG_ERROR_TEXT_SUPPORTED | |
400 PNG_UNUSED(error_message) | |
401 # endif | |
402 } | |
403 | |
404 void /* PRIVATE */ | |
405 png_app_error(png_const_structrp png_ptr, png_const_charp error_message) | |
406 { | |
407 if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0) | |
408 png_warning(png_ptr, error_message); | |
409 else | |
410 png_error(png_ptr, error_message); | |
411 | |
412 # ifndef PNG_ERROR_TEXT_SUPPORTED | |
413 PNG_UNUSED(error_message) | |
414 # endif | |
415 } | |
416 #endif /* BENIGN_ERRORS */ | |
417 | |
418 #define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */ | |
419 #if defined(PNG_WARNINGS_SUPPORTED) || \ | |
420 (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)) | |
421 /* These utilities are used internally to build an error message that relates | |
422 * to the current chunk. The chunk name comes from png_ptr->chunk_name, | |
423 * which is used to prefix the message. The message is limited in length | |
424 * to 63 bytes. The name characters are output as hex digits wrapped in [] | |
425 * if the character is invalid. | |
426 */ | |
427 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) | |
428 static PNG_CONST char png_digit[16] = { | |
429 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', | |
430 'A', 'B', 'C', 'D', 'E', 'F' | |
431 }; | |
432 | |
433 static void /* PRIVATE */ | |
434 png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp | |
435 error_message) | |
436 { | |
437 png_uint_32 chunk_name = png_ptr->chunk_name; | |
438 int iout = 0, ishift = 24; | |
439 | |
440 while (ishift >= 0) | |
441 { | |
442 int c = (int)(chunk_name >> ishift) & 0xff; | |
443 | |
444 ishift -= 8; | |
445 if (isnonalpha(c) != 0) | |
446 { | |
447 buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET; | |
448 buffer[iout++] = png_digit[(c & 0xf0) >> 4]; | |
449 buffer[iout++] = png_digit[c & 0x0f]; | |
450 buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET; | |
451 } | |
452 | |
453 else | |
454 { | |
455 buffer[iout++] = (char)c; | |
456 } | |
457 } | |
458 | |
459 if (error_message == NULL) | |
460 buffer[iout] = '\0'; | |
461 | |
462 else | |
463 { | |
464 int iin = 0; | |
465 | |
466 buffer[iout++] = ':'; | |
467 buffer[iout++] = ' '; | |
468 | |
469 while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0') | |
470 buffer[iout++] = error_message[iin++]; | |
471 | |
472 /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */ | |
473 buffer[iout] = '\0'; | |
474 } | |
475 } | |
476 #endif /* WARNINGS || ERROR_TEXT */ | |
477 | |
478 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED) | |
479 PNG_FUNCTION(void,PNGAPI | |
480 png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message), | |
481 PNG_NORETURN) | |
482 { | |
483 char msg[18+PNG_MAX_ERROR_TEXT]; | |
484 if (png_ptr == NULL) | |
485 png_error(png_ptr, error_message); | |
486 | |
487 else | |
488 { | |
489 png_format_buffer(png_ptr, msg, error_message); | |
490 png_error(png_ptr, msg); | |
491 } | |
492 } | |
493 #endif /* READ && ERROR_TEXT */ | |
494 | |
495 #ifdef PNG_WARNINGS_SUPPORTED | |
496 void PNGAPI | |
497 png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message) | |
498 { | |
499 char msg[18+PNG_MAX_ERROR_TEXT]; | |
500 if (png_ptr == NULL) | |
501 png_warning(png_ptr, warning_message); | |
502 | |
503 else | |
504 { | |
505 png_format_buffer(png_ptr, msg, warning_message); | |
506 png_warning(png_ptr, msg); | |
507 } | |
508 } | |
509 #endif /* WARNINGS */ | |
510 | |
511 #ifdef PNG_READ_SUPPORTED | |
512 #ifdef PNG_BENIGN_ERRORS_SUPPORTED | |
513 void PNGAPI | |
514 png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp | |
515 error_message) | |
516 { | |
517 if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0) | |
518 png_chunk_warning(png_ptr, error_message); | |
519 | |
520 else | |
521 png_chunk_error(png_ptr, error_message); | |
522 | |
523 # ifndef PNG_ERROR_TEXT_SUPPORTED | |
524 PNG_UNUSED(error_message) | |
525 # endif | |
526 } | |
527 #endif | |
528 #endif /* READ */ | |
529 | |
530 void /* PRIVATE */ | |
531 png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error) | |
532 { | |
533 # ifndef PNG_WARNINGS_SUPPORTED | |
534 PNG_UNUSED(message) | |
535 # endif | |
536 | |
537 /* This is always supported, but for just read or just write it | |
538 * unconditionally does the right thing. | |
539 */ | |
540 # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) | |
541 if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0) | |
542 # endif | |
543 | |
544 # ifdef PNG_READ_SUPPORTED | |
545 { | |
546 if (error < PNG_CHUNK_ERROR) | |
547 png_chunk_warning(png_ptr, message); | |
548 | |
549 else | |
550 png_chunk_benign_error(png_ptr, message); | |
551 } | |
552 # endif | |
553 | |
554 # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) | |
555 else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0) | |
556 # endif | |
557 | |
558 # ifdef PNG_WRITE_SUPPORTED | |
559 { | |
560 if (error < PNG_CHUNK_WRITE_ERROR) | |
561 png_app_warning(png_ptr, message); | |
562 | |
563 else | |
564 png_app_error(png_ptr, message); | |
565 } | |
566 # endif | |
567 } | |
568 | |
569 #ifdef PNG_ERROR_TEXT_SUPPORTED | |
570 #ifdef PNG_FLOATING_POINT_SUPPORTED | |
571 PNG_FUNCTION(void, | |
572 png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN) | |
573 { | |
574 # define fixed_message "fixed point overflow in " | |
575 # define fixed_message_ln ((sizeof fixed_message)-1) | |
576 int iin; | |
577 char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT]; | |
578 memcpy(msg, fixed_message, fixed_message_ln); | |
579 iin = 0; | |
580 if (name != NULL) | |
581 while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0) | |
582 { | |
583 msg[fixed_message_ln + iin] = name[iin]; | |
584 ++iin; | |
585 } | |
586 msg[fixed_message_ln + iin] = 0; | |
587 png_error(png_ptr, msg); | |
588 } | |
589 #endif | |
590 #endif | |
591 | |
592 #ifdef PNG_SETJMP_SUPPORTED | |
593 /* This API only exists if ANSI-C style error handling is used, | |
594 * otherwise it is necessary for png_default_error to be overridden. | |
595 */ | |
596 jmp_buf* PNGAPI | |
597 png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn, | |
598 size_t jmp_buf_size) | |
599 { | |
600 /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value | |
601 * and it must not change after that. Libpng doesn't care how big the | |
602 * buffer is, just that it doesn't change. | |
603 * | |
604 * If the buffer size is no *larger* than the size of jmp_buf when libpng is | |
605 * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0 | |
606 * semantics that this call will not fail. If the size is larger, however, | |
607 * the buffer is allocated and this may fail, causing the function to return | |
608 * NULL. | |
609 */ | |
610 if (png_ptr == NULL) | |
611 return NULL; | |
612 | |
613 if (png_ptr->jmp_buf_ptr == NULL) | |
614 { | |
615 png_ptr->jmp_buf_size = 0; /* not allocated */ | |
616 | |
617 if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local)) | |
618 png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; | |
619 | |
620 else | |
621 { | |
622 png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *, | |
623 png_malloc_warn(png_ptr, jmp_buf_size)); | |
624 | |
625 if (png_ptr->jmp_buf_ptr == NULL) | |
626 return NULL; /* new NULL return on OOM */ | |
627 | |
628 png_ptr->jmp_buf_size = jmp_buf_size; | |
629 } | |
630 } | |
631 | |
632 else /* Already allocated: check the size */ | |
633 { | |
634 size_t size = png_ptr->jmp_buf_size; | |
635 | |
636 if (size == 0) | |
637 { | |
638 size = (sizeof png_ptr->jmp_buf_local); | |
639 if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local) | |
640 { | |
641 /* This is an internal error in libpng: somehow we have been left | |
642 * with a stack allocated jmp_buf when the application regained | |
643 * control. It's always possible to fix this up, but for the moment | |
644 * this is a png_error because that makes it easy to detect. | |
645 */ | |
646 png_error(png_ptr, "Libpng jmp_buf still allocated"); | |
647 /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */ | |
648 } | |
649 } | |
650 | |
651 if (size != jmp_buf_size) | |
652 { | |
653 png_warning(png_ptr, "Application jmp_buf size changed"); | |
654 return NULL; /* caller will probably crash: no choice here */ | |
655 } | |
656 } | |
657 | |
658 /* Finally fill in the function, now we have a satisfactory buffer. It is | |
659 * valid to change the function on every call. | |
660 */ | |
661 png_ptr->longjmp_fn = longjmp_fn; | |
662 return png_ptr->jmp_buf_ptr; | |
663 } | |
664 | |
665 void /* PRIVATE */ | |
666 png_free_jmpbuf(png_structrp png_ptr) | |
667 { | |
668 if (png_ptr != NULL) | |
669 { | |
670 jmp_buf *jb = png_ptr->jmp_buf_ptr; | |
671 | |
672 /* A size of 0 is used to indicate a local, stack, allocation of the | |
673 * pointer; used here and in png.c | |
674 */ | |
675 if (jb != NULL && png_ptr->jmp_buf_size > 0) | |
676 { | |
677 | |
678 /* This stuff is so that a failure to free the error control structure | |
679 * does not leave libpng in a state with no valid error handling: the | |
680 * free always succeeds, if there is an error it gets ignored. | |
681 */ | |
682 if (jb != &png_ptr->jmp_buf_local) | |
683 { | |
684 /* Make an internal, libpng, jmp_buf to return here */ | |
685 jmp_buf free_jmp_buf; | |
686 | |
687 if (!setjmp(free_jmp_buf)) | |
688 { | |
689 png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */ | |
690 png_ptr->jmp_buf_size = 0; /* stack allocation */ | |
691 png_ptr->longjmp_fn = longjmp; | |
692 png_free(png_ptr, jb); /* Return to setjmp on error */ | |
693 } | |
694 } | |
695 } | |
696 | |
697 /* *Always* cancel everything out: */ | |
698 png_ptr->jmp_buf_size = 0; | |
699 png_ptr->jmp_buf_ptr = NULL; | |
700 png_ptr->longjmp_fn = 0; | |
701 } | |
702 } | |
703 #endif | |
704 | |
705 /* This is the default error handling function. Note that replacements for | |
706 * this function MUST NOT RETURN, or the program will likely crash. This | |
707 * function is used by default, or if the program supplies NULL for the | |
708 * error function pointer in png_set_error_fn(). | |
709 */ | |
710 static PNG_FUNCTION(void /* PRIVATE */, | |
711 png_default_error,(png_const_structrp png_ptr, png_const_charp error_message), | |
712 PNG_NORETURN) | |
713 { | |
714 #ifdef PNG_CONSOLE_IO_SUPPORTED | |
715 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
716 /* Check on NULL only added in 1.5.4 */ | |
717 if (error_message != NULL && *error_message == PNG_LITERAL_SHARP) | |
718 { | |
719 /* Strip "#nnnn " from beginning of error message. */ | |
720 int offset; | |
721 char error_number[16]; | |
722 for (offset = 0; offset<15; offset++) | |
723 { | |
724 error_number[offset] = error_message[offset + 1]; | |
725 if (error_message[offset] == ' ') | |
726 break; | |
727 } | |
728 | |
729 if ((offset > 1) && (offset < 15)) | |
730 { | |
731 error_number[offset - 1] = '\0'; | |
732 fprintf(stderr, "libpng error no. %s: %s", | |
733 error_number, error_message + offset + 1); | |
734 fprintf(stderr, PNG_STRING_NEWLINE); | |
735 } | |
736 | |
737 else | |
738 { | |
739 fprintf(stderr, "libpng error: %s, offset=%d", | |
740 error_message, offset); | |
741 fprintf(stderr, PNG_STRING_NEWLINE); | |
742 } | |
743 } | |
744 else | |
745 #endif | |
746 { | |
747 fprintf(stderr, "libpng error: %s", error_message ? error_message : | |
748 "undefined"); | |
749 fprintf(stderr, PNG_STRING_NEWLINE); | |
750 } | |
751 #else | |
752 PNG_UNUSED(error_message) /* Make compiler happy */ | |
753 #endif | |
754 png_longjmp(png_ptr, 1); | |
755 } | |
756 | |
757 PNG_FUNCTION(void,PNGAPI | |
758 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN) | |
759 { | |
760 #ifdef PNG_SETJMP_SUPPORTED | |
761 if (png_ptr != NULL && png_ptr->longjmp_fn != NULL && | |
762 png_ptr->jmp_buf_ptr != NULL) | |
763 png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val); | |
764 #else | |
765 PNG_UNUSED(png_ptr) | |
766 PNG_UNUSED(val) | |
767 #endif | |
768 | |
769 /* If control reaches this point, png_longjmp() must not return. The only | |
770 * choice is to terminate the whole process (or maybe the thread); to do | |
771 * this the ANSI-C abort() function is used unless a different method is | |
772 * implemented by overriding the default configuration setting for | |
773 * PNG_ABORT(). | |
774 */ | |
775 PNG_ABORT(); | |
776 } | |
777 | |
778 #ifdef PNG_WARNINGS_SUPPORTED | |
779 /* This function is called when there is a warning, but the library thinks | |
780 * it can continue anyway. Replacement functions don't have to do anything | |
781 * here if you don't want them to. In the default configuration, png_ptr is | |
782 * not used, but it is passed in case it may be useful. | |
783 */ | |
784 static void /* PRIVATE */ | |
785 png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message) | |
786 { | |
787 #ifdef PNG_CONSOLE_IO_SUPPORTED | |
788 # ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
789 if (*warning_message == PNG_LITERAL_SHARP) | |
790 { | |
791 int offset; | |
792 char warning_number[16]; | |
793 for (offset = 0; offset < 15; offset++) | |
794 { | |
795 warning_number[offset] = warning_message[offset + 1]; | |
796 if (warning_message[offset] == ' ') | |
797 break; | |
798 } | |
799 | |
800 if ((offset > 1) && (offset < 15)) | |
801 { | |
802 warning_number[offset + 1] = '\0'; | |
803 fprintf(stderr, "libpng warning no. %s: %s", | |
804 warning_number, warning_message + offset); | |
805 fprintf(stderr, PNG_STRING_NEWLINE); | |
806 } | |
807 | |
808 else | |
809 { | |
810 fprintf(stderr, "libpng warning: %s", | |
811 warning_message); | |
812 fprintf(stderr, PNG_STRING_NEWLINE); | |
813 } | |
814 } | |
815 else | |
816 # endif | |
817 | |
818 { | |
819 fprintf(stderr, "libpng warning: %s", warning_message); | |
820 fprintf(stderr, PNG_STRING_NEWLINE); | |
821 } | |
822 #else | |
823 PNG_UNUSED(warning_message) /* Make compiler happy */ | |
824 #endif | |
825 PNG_UNUSED(png_ptr) /* Make compiler happy */ | |
826 } | |
827 #endif /* WARNINGS */ | |
828 | |
829 /* This function is called when the application wants to use another method | |
830 * of handling errors and warnings. Note that the error function MUST NOT | |
831 * return to the calling routine or serious problems will occur. The return | |
832 * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1) | |
833 */ | |
834 void PNGAPI | |
835 png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr, | |
836 png_error_ptr error_fn, png_error_ptr warning_fn) | |
837 { | |
838 if (png_ptr == NULL) | |
839 return; | |
840 | |
841 png_ptr->error_ptr = error_ptr; | |
842 png_ptr->error_fn = error_fn; | |
843 #ifdef PNG_WARNINGS_SUPPORTED | |
844 png_ptr->warning_fn = warning_fn; | |
845 #else | |
846 PNG_UNUSED(warning_fn) | |
847 #endif | |
848 } | |
849 | |
850 | |
851 /* This function returns a pointer to the error_ptr associated with the user | |
852 * functions. The application should free any memory associated with this | |
853 * pointer before png_write_destroy and png_read_destroy are called. | |
854 */ | |
855 png_voidp PNGAPI | |
856 png_get_error_ptr(png_const_structrp png_ptr) | |
857 { | |
858 if (png_ptr == NULL) | |
859 return NULL; | |
860 | |
861 return ((png_voidp)png_ptr->error_ptr); | |
862 } | |
863 | |
864 | |
865 #ifdef PNG_ERROR_NUMBERS_SUPPORTED | |
866 void PNGAPI | |
867 png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode) | |
868 { | |
869 if (png_ptr != NULL) | |
870 { | |
871 png_ptr->flags &= | |
872 ((~(PNG_FLAG_STRIP_ERROR_NUMBERS | | |
873 PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode); | |
874 } | |
875 } | |
876 #endif | |
877 | |
878 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ | |
879 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) | |
880 /* Currently the above both depend on SETJMP_SUPPORTED, however it would be | |
881 * possible to implement without setjmp support just so long as there is some | |
882 * way to handle the error return here: | |
883 */ | |
884 PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI | |
885 png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message), | |
886 PNG_NORETURN) | |
887 { | |
888 const png_const_structrp png_ptr = png_nonconst_ptr; | |
889 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); | |
890 | |
891 /* An error is always logged here, overwriting anything (typically a warning) | |
892 * that is already there: | |
893 */ | |
894 if (image != NULL) | |
895 { | |
896 png_safecat(image->message, (sizeof image->message), 0, error_message); | |
897 image->warning_or_error |= PNG_IMAGE_ERROR; | |
898 | |
899 /* Retrieve the jmp_buf from within the png_control, making this work for | |
900 * C++ compilation too is pretty tricky: C++ wants a pointer to the first | |
901 * element of a jmp_buf, but C doesn't tell us the type of that. | |
902 */ | |
903 if (image->opaque != NULL && image->opaque->error_buf != NULL) | |
904 longjmp(png_control_jmp_buf(image->opaque), 1); | |
905 | |
906 /* Missing longjmp buffer, the following is to help debugging: */ | |
907 { | |
908 size_t pos = png_safecat(image->message, (sizeof image->message), 0, | |
909 "bad longjmp: "); | |
910 png_safecat(image->message, (sizeof image->message), pos, | |
911 error_message); | |
912 } | |
913 } | |
914 | |
915 /* Here on an internal programming error. */ | |
916 abort(); | |
917 } | |
918 | |
919 #ifdef PNG_WARNINGS_SUPPORTED | |
920 void /* PRIVATE */ PNGCBAPI | |
921 png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message) | |
922 { | |
923 const png_const_structrp png_ptr = png_nonconst_ptr; | |
924 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); | |
925 | |
926 /* A warning is only logged if there is no prior warning or error. */ | |
927 if (image->warning_or_error == 0) | |
928 { | |
929 png_safecat(image->message, (sizeof image->message), 0, warning_message); | |
930 image->warning_or_error |= PNG_IMAGE_WARNING; | |
931 } | |
932 } | |
933 #endif | |
934 | |
935 int /* PRIVATE */ | |
936 png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg) | |
937 { | |
938 volatile png_imagep image = image_in; | |
939 volatile int result; | |
940 volatile png_voidp saved_error_buf; | |
941 jmp_buf safe_jmpbuf; | |
942 | |
943 /* Safely execute function(arg) with png_error returning to this function. */ | |
944 saved_error_buf = image->opaque->error_buf; | |
945 result = setjmp(safe_jmpbuf) == 0; | |
946 | |
947 if (result != 0) | |
948 { | |
949 | |
950 image->opaque->error_buf = safe_jmpbuf; | |
951 result = function(arg); | |
952 } | |
953 | |
954 image->opaque->error_buf = saved_error_buf; | |
955 | |
956 /* And do the cleanup prior to any failure return. */ | |
957 if (result == 0) | |
958 png_image_free(image); | |
959 | |
960 return result; | |
961 } | |
962 #endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */ | |
963 #endif /* READ || WRITE */ | |
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