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Side by Side Diff: third_party/lpng_v163/pngerror.c

Issue 1591483003: XFA: Upgrade libpng to 1.6.20. (Closed) Base URL: https://pdfium.googlesource.com/pdfium.git@xfa
Patch Set: rebase Created 4 years, 11 months ago
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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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