Line data Source code
1 :
2 : /* pngerror.c - stub functions for i/o and memory allocation
3 : *
4 : * Last changed in libpng 1.6.26 [October 20, 2016]
5 : * Copyright (c) 1998-2002,2004,2006-2016 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 0 : 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 0 : if (png_ptr != NULL && png_ptr->error_fn != NULL)
83 0 : (*(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 0 : 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 0 : png_safecat(png_charp buffer, size_t bufsize, size_t pos,
113 : png_const_charp string)
114 : {
115 0 : if (buffer != NULL && pos < bufsize)
116 : {
117 0 : if (string != NULL)
118 0 : while (*string != '\0' && pos < bufsize-1)
119 0 : buffer[pos++] = *string++;
120 :
121 0 : buffer[pos] = '\0';
122 : }
123 :
124 0 : 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 0 : png_format_number(png_const_charp start, png_charp end, int format,
134 : png_alloc_size_t number)
135 : {
136 0 : int count = 0; /* number of digits output */
137 0 : int mincount = 1; /* minimum number required */
138 0 : int output = 0; /* digit output (for the fixed point format) */
139 :
140 0 : *--end = '\0';
141 :
142 : /* This is written so that the loop always runs at least once, even with
143 : * number zero.
144 : */
145 0 : while (end > start && (number != 0 || count < mincount))
146 : {
147 :
148 : static const char digits[] = "0123456789ABCDEF";
149 :
150 0 : switch (format)
151 : {
152 : case PNG_NUMBER_FORMAT_fixed:
153 : /* Needs five digits (the fraction) */
154 0 : mincount = 5;
155 0 : if (output != 0 || number % 10 != 0)
156 : {
157 0 : *--end = digits[number % 10];
158 0 : output = 1;
159 : }
160 0 : number /= 10;
161 0 : break;
162 :
163 : case PNG_NUMBER_FORMAT_02u:
164 : /* Expects at least 2 digits. */
165 0 : mincount = 2;
166 : /* FALL THROUGH */
167 :
168 : case PNG_NUMBER_FORMAT_u:
169 0 : *--end = digits[number % 10];
170 0 : number /= 10;
171 0 : break;
172 :
173 : case PNG_NUMBER_FORMAT_02x:
174 : /* This format expects at least two digits */
175 0 : mincount = 2;
176 : /* FALL THROUGH */
177 :
178 : case PNG_NUMBER_FORMAT_x:
179 0 : *--end = digits[number & 0xf];
180 0 : number >>= 4;
181 0 : break;
182 :
183 : default: /* an error */
184 0 : number = 0;
185 0 : break;
186 : }
187 :
188 : /* Keep track of the number of digits added */
189 0 : ++count;
190 :
191 : /* Float a fixed number here: */
192 0 : 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 0 : if (output != 0)
199 0 : *--end = '.';
200 0 : else if (number == 0) /* and !output */
201 0 : *--end = '0';
202 : }
203 : }
204 :
205 0 : 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 0 : png_warning(png_const_structrp png_ptr, png_const_charp warning_message)
217 : {
218 0 : int offset = 0;
219 0 : 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 0 : if (*warning_message == PNG_LITERAL_SHARP)
227 : {
228 0 : for (offset = 1; offset < 15; offset++)
229 0 : if (warning_message[offset] == ' ')
230 0 : break;
231 : }
232 : }
233 : }
234 0 : if (png_ptr != NULL && png_ptr->warning_fn != NULL)
235 0 : (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr),
236 : warning_message + offset);
237 : else
238 0 : png_default_warning(png_ptr, warning_message + offset);
239 0 : }
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 0 : png_warning_parameter(png_warning_parameters p, int number,
248 : png_const_charp string)
249 : {
250 0 : if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT)
251 0 : (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string);
252 0 : }
253 :
254 : void
255 0 : 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 0 : png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value));
260 0 : }
261 :
262 : void
263 0 : 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 0 : u = (png_alloc_size_t)value;
272 0 : if (value < 0)
273 0 : u = ~u + 1;
274 :
275 0 : str = PNG_FORMAT_NUMBER(buffer, format, u);
276 :
277 0 : if (value < 0 && str > buffer)
278 0 : *--str = '-';
279 :
280 0 : png_warning_parameter(p, number, str);
281 0 : }
282 :
283 : void
284 0 : 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 0 : 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 0 : 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 0 : if (p != NULL && *message == '@' && message[1] != '\0')
307 : {
308 0 : int parameter_char = *++message; /* Consume the '@' */
309 : static const char valid_parameters[] = "123456789";
310 0 : int parameter = 0;
311 :
312 : /* Search for the parameter digit, the index in the string is the
313 : * parameter to use.
314 : */
315 0 : while (valid_parameters[parameter] != parameter_char &&
316 0 : valid_parameters[parameter] != '\0')
317 0 : ++parameter;
318 :
319 : /* If the parameter digit is out of range it will just get printed. */
320 0 : if (parameter < PNG_WARNING_PARAMETER_COUNT)
321 : {
322 : /* Append this parameter */
323 0 : png_const_charp parm = p[parameter];
324 0 : 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 0 : while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend)
331 0 : msg[i++] = *parm++;
332 :
333 : /* Consume the parameter digit too: */
334 0 : ++message;
335 0 : 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 0 : msg[i++] = *message++;
347 : }
348 :
349 : /* i is always less than (sizeof msg), so: */
350 0 : 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 0 : png_warning(png_ptr, msg);
357 0 : }
358 : #endif /* WARNINGS */
359 :
360 : #ifdef PNG_BENIGN_ERRORS_SUPPORTED
361 : void PNGAPI
362 0 : png_benign_error(png_const_structrp png_ptr, png_const_charp error_message)
363 : {
364 0 : if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
365 : {
366 : # ifdef PNG_READ_SUPPORTED
367 0 : if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
368 0 : png_ptr->chunk_name != 0)
369 0 : png_chunk_warning(png_ptr, error_message);
370 : else
371 : # endif
372 0 : png_warning(png_ptr, error_message);
373 : }
374 :
375 : else
376 : {
377 : # ifdef PNG_READ_SUPPORTED
378 0 : if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 &&
379 0 : png_ptr->chunk_name != 0)
380 0 : png_chunk_error(png_ptr, error_message);
381 : else
382 : # endif
383 0 : png_error(png_ptr, error_message);
384 : }
385 :
386 : # ifndef PNG_ERROR_TEXT_SUPPORTED
387 : PNG_UNUSED(error_message)
388 : # endif
389 0 : }
390 :
391 : void /* PRIVATE */
392 0 : png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
393 : {
394 0 : if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
395 0 : png_warning(png_ptr, error_message);
396 : else
397 0 : png_error(png_ptr, error_message);
398 :
399 : # ifndef PNG_ERROR_TEXT_SUPPORTED
400 : PNG_UNUSED(error_message)
401 : # endif
402 0 : }
403 :
404 : void /* PRIVATE */
405 0 : png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
406 : {
407 0 : if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
408 0 : png_warning(png_ptr, error_message);
409 : else
410 0 : png_error(png_ptr, error_message);
411 :
412 : # ifndef PNG_ERROR_TEXT_SUPPORTED
413 : PNG_UNUSED(error_message)
414 : # endif
415 0 : }
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 0 : png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp
435 : error_message)
436 : {
437 0 : png_uint_32 chunk_name = png_ptr->chunk_name;
438 0 : int iout = 0, ishift = 24;
439 :
440 0 : while (ishift >= 0)
441 : {
442 0 : int c = (int)(chunk_name >> ishift) & 0xff;
443 :
444 0 : ishift -= 8;
445 0 : if (isnonalpha(c) != 0)
446 : {
447 0 : buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
448 0 : buffer[iout++] = png_digit[(c & 0xf0) >> 4];
449 0 : buffer[iout++] = png_digit[c & 0x0f];
450 0 : buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
451 : }
452 :
453 : else
454 : {
455 0 : buffer[iout++] = (char)c;
456 : }
457 : }
458 :
459 0 : if (error_message == NULL)
460 0 : buffer[iout] = '\0';
461 :
462 : else
463 : {
464 0 : int iin = 0;
465 :
466 0 : buffer[iout++] = ':';
467 0 : buffer[iout++] = ' ';
468 :
469 0 : while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0')
470 0 : buffer[iout++] = error_message[iin++];
471 :
472 : /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */
473 0 : buffer[iout] = '\0';
474 : }
475 0 : }
476 : #endif /* WARNINGS || ERROR_TEXT */
477 :
478 : #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
479 0 : 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 0 : if (png_ptr == NULL)
485 0 : png_error(png_ptr, error_message);
486 :
487 : else
488 : {
489 0 : png_format_buffer(png_ptr, msg, error_message);
490 0 : png_error(png_ptr, msg);
491 : }
492 : }
493 : #endif /* READ && ERROR_TEXT */
494 :
495 : #ifdef PNG_WARNINGS_SUPPORTED
496 : void PNGAPI
497 0 : png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message)
498 : {
499 : char msg[18+PNG_MAX_ERROR_TEXT];
500 0 : if (png_ptr == NULL)
501 0 : png_warning(png_ptr, warning_message);
502 :
503 : else
504 : {
505 0 : png_format_buffer(png_ptr, msg, warning_message);
506 0 : png_warning(png_ptr, msg);
507 : }
508 0 : }
509 : #endif /* WARNINGS */
510 :
511 : #ifdef PNG_READ_SUPPORTED
512 : #ifdef PNG_BENIGN_ERRORS_SUPPORTED
513 : void PNGAPI
514 0 : png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp
515 : error_message)
516 : {
517 0 : if ((png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) != 0)
518 0 : png_chunk_warning(png_ptr, error_message);
519 :
520 : else
521 0 : png_chunk_error(png_ptr, error_message);
522 :
523 : # ifndef PNG_ERROR_TEXT_SUPPORTED
524 : PNG_UNUSED(error_message)
525 : # endif
526 0 : }
527 : #endif
528 : #endif /* READ */
529 :
530 : void /* PRIVATE */
531 0 : 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 0 : if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
542 : # endif
543 :
544 : # ifdef PNG_READ_SUPPORTED
545 : {
546 0 : if (error < PNG_CHUNK_ERROR)
547 0 : png_chunk_warning(png_ptr, message);
548 :
549 : else
550 0 : png_chunk_benign_error(png_ptr, message);
551 : }
552 : # endif
553 :
554 : # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED)
555 0 : else if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
556 : # endif
557 :
558 : # ifdef PNG_WRITE_SUPPORTED
559 : {
560 0 : if (error < PNG_CHUNK_WRITE_ERROR)
561 0 : png_app_warning(png_ptr, message);
562 :
563 : else
564 0 : png_app_error(png_ptr, message);
565 : }
566 : # endif
567 0 : }
568 :
569 : #ifdef PNG_ERROR_TEXT_SUPPORTED
570 : #ifdef PNG_FLOATING_POINT_SUPPORTED
571 0 : 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 : unsigned int iin;
577 : char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
578 0 : memcpy(msg, fixed_message, fixed_message_ln);
579 0 : iin = 0;
580 0 : if (name != NULL)
581 0 : while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
582 : {
583 0 : msg[fixed_message_ln + iin] = name[iin];
584 0 : ++iin;
585 : }
586 0 : msg[fixed_message_ln + iin] = 0;
587 0 : 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 65 : 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 65 : if (png_ptr == NULL)
611 0 : return NULL;
612 :
613 65 : if (png_ptr->jmp_buf_ptr == NULL)
614 : {
615 31 : png_ptr->jmp_buf_size = 0; /* not allocated */
616 :
617 31 : if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local))
618 31 : png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local;
619 :
620 : else
621 : {
622 0 : png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *,
623 : png_malloc_warn(png_ptr, jmp_buf_size));
624 :
625 0 : if (png_ptr->jmp_buf_ptr == NULL)
626 0 : return NULL; /* new NULL return on OOM */
627 :
628 0 : png_ptr->jmp_buf_size = jmp_buf_size;
629 : }
630 : }
631 :
632 : else /* Already allocated: check the size */
633 : {
634 34 : size_t size = png_ptr->jmp_buf_size;
635 :
636 34 : if (size == 0)
637 : {
638 34 : size = (sizeof png_ptr->jmp_buf_local);
639 34 : 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 0 : png_error(png_ptr, "Libpng jmp_buf still allocated");
647 : /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */
648 : }
649 : }
650 :
651 34 : if (size != jmp_buf_size)
652 : {
653 0 : png_warning(png_ptr, "Application jmp_buf size changed");
654 0 : 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 65 : png_ptr->longjmp_fn = longjmp_fn;
662 65 : return png_ptr->jmp_buf_ptr;
663 : }
664 :
665 : void /* PRIVATE */
666 31 : png_free_jmpbuf(png_structrp png_ptr)
667 : {
668 31 : if (png_ptr != NULL)
669 : {
670 31 : 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 31 : 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 0 : 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 0 : if (!setjmp(free_jmp_buf))
688 : {
689 0 : png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */
690 0 : png_ptr->jmp_buf_size = 0; /* stack allocation */
691 0 : png_ptr->longjmp_fn = longjmp;
692 0 : png_free(png_ptr, jb); /* Return to setjmp on error */
693 : }
694 : }
695 : }
696 :
697 : /* *Always* cancel everything out: */
698 31 : png_ptr->jmp_buf_size = 0;
699 31 : png_ptr->jmp_buf_ptr = NULL;
700 31 : png_ptr->longjmp_fn = 0;
701 : }
702 31 : }
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 0 : 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 0 : png_longjmp(png_ptr, 1);
755 : }
756 :
757 0 : PNG_FUNCTION(void,PNGAPI
758 : png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN)
759 : {
760 : #ifdef PNG_SETJMP_SUPPORTED
761 0 : if (png_ptr != NULL && png_ptr->longjmp_fn != NULL &&
762 0 : png_ptr->jmp_buf_ptr != NULL)
763 0 : 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 0 : 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 0 : 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 0 : }
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 31 : 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 31 : if (png_ptr == NULL)
839 0 : return;
840 :
841 31 : png_ptr->error_ptr = error_ptr;
842 31 : png_ptr->error_fn = error_fn;
843 : #ifdef PNG_WARNINGS_SUPPORTED
844 31 : 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 0 : png_get_error_ptr(png_const_structrp png_ptr)
857 : {
858 0 : if (png_ptr == NULL)
859 0 : return NULL;
860 :
861 0 : 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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