1 2 /* pngerror.c - stub functions for i/o and memory allocation 3 * 4 * Last changed in libpng 1.6.10 [March 6, 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 /* PNG_WARNINGS_SUPPORTED */ 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)) 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) 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) 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 /* PNG_ERROR_TEXT_SUPPORTED */ 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 || 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) if (count == 5) if (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) 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)) 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 /* PNG_WARNINGS_SUPPORTED */ 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) 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) 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) 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 /* These utilities are used internally to build an error message that relates 419 * to the current chunk. The chunk name comes from png_ptr->chunk_name, 420 * this is used to prefix the message. The message is limited in length 421 * to 63 bytes, the name characters are output as hex digits wrapped in [] 422 * if the character is invalid. 423 */ 424 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) 425 static PNG_CONST char png_digit[16] = { 426 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 427 'A', 'B', 'C', 'D', 'E', 'F' 428 }; 429 430 #define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */ 431 #if defined(PNG_WARNINGS_SUPPORTED) || \ 432 (defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)) 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)) 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 /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */ 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 /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */ 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 /* PNG_WARNINGS_SUPPORTED */ 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) 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 /* PNG_READ_SUPPORTED */ 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) 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)) 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) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0) 581 { 582 msg[fixed_message_ln + iin] = name[iin]; 583 ++iin; 584 } 585 msg[fixed_message_ln + iin] = 0; 586 png_error(png_ptr, msg); 587 } 588 #endif 589 #endif 590 591 #ifdef PNG_SETJMP_SUPPORTED 592 /* This API only exists if ANSI-C style error handling is used, 593 * otherwise it is necessary for png_default_error to be overridden. 594 */ 595 jmp_buf* PNGAPI 596 png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn, 597 size_t jmp_buf_size) 598 { 599 /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value 600 * and it must not change after that. Libpng doesn't care how big the 601 * buffer is, just that it doesn't change. 602 * 603 * If the buffer size is no *larger* than the size of jmp_buf when libpng is 604 * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0 605 * semantics that this call will not fail. If the size is larger, however, 606 * the buffer is allocated and this may fail, causing the function to return 607 * NULL. 608 */ 609 if (png_ptr == NULL) 610 return NULL; 611 612 if (png_ptr->jmp_buf_ptr == NULL) 613 { 614 png_ptr->jmp_buf_size = 0; /* not allocated */ 615 616 if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local)) 617 png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; 618 619 else 620 { 621 png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *, 622 png_malloc_warn(png_ptr, jmp_buf_size)); 623 624 if (png_ptr->jmp_buf_ptr == NULL) 625 return NULL; /* new NULL return on OOM */ 626 627 png_ptr->jmp_buf_size = jmp_buf_size; 628 } 629 } 630 631 else /* Already allocated: check the size */ 632 { 633 size_t size = png_ptr->jmp_buf_size; 634 635 if (size == 0) 636 { 637 size = (sizeof png_ptr->jmp_buf_local); 638 if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local) 639 { 640 /* This is an internal error in libpng: somehow we have been left 641 * with a stack allocated jmp_buf when the application regained 642 * control. It's always possible to fix this up, but for the moment 643 * this is a png_error because that makes it easy to detect. 644 */ 645 png_error(png_ptr, "Libpng jmp_buf still allocated"); 646 /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */ 647 } 648 } 649 650 if (size != jmp_buf_size) 651 { 652 png_warning(png_ptr, "Application jmp_buf size changed"); 653 return NULL; /* caller will probably crash: no choice here */ 654 } 655 } 656 657 /* Finally fill in the function, now we have a satisfactory buffer. It is 658 * valid to change the function on every call. 659 */ 660 png_ptr->longjmp_fn = longjmp_fn; 661 return png_ptr->jmp_buf_ptr; 662 } 663 664 void /* PRIVATE */ 665 png_free_jmpbuf(png_structrp png_ptr) 666 { 667 if (png_ptr != NULL) 668 { 669 jmp_buf *jb = png_ptr->jmp_buf_ptr; 670 671 /* A size of 0 is used to indicate a local, stack, allocation of the 672 * pointer; used here and in png.c 673 */ 674 if (jb != NULL && png_ptr->jmp_buf_size > 0) 675 { 676 677 /* This stuff is so that a failure to free the error control structure 678 * does not leave libpng in a state with no valid error handling: the 679 * free always succeeds, if there is an error it gets ignored. 680 */ 681 if (jb != &png_ptr->jmp_buf_local) 682 { 683 /* Make an internal, libpng, jmp_buf to return here */ 684 jmp_buf free_jmp_buf; 685 686 if (!setjmp(free_jmp_buf)) 687 { 688 png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */ 689 png_ptr->jmp_buf_size = 0; /* stack allocation */ 690 png_ptr->longjmp_fn = longjmp; 691 png_free(png_ptr, jb); /* Return to setjmp on error */ 692 } 693 } 694 } 695 696 /* *Always* cancel everything out: */ 697 png_ptr->jmp_buf_size = 0; 698 png_ptr->jmp_buf_ptr = NULL; 699 png_ptr->longjmp_fn = 0; 700 } 701 } 702 #endif 703 704 /* This is the default error handling function. Note that replacements for 705 * this function MUST NOT RETURN, or the program will likely crash. This 706 * function is used by default, or if the program supplies NULL for the 707 * error function pointer in png_set_error_fn(). 708 */ 709 static PNG_FUNCTION(void /* PRIVATE */, 710 png_default_error,(png_const_structrp png_ptr, png_const_charp error_message), 711 PNG_NORETURN) 712 { 713 #ifdef PNG_CONSOLE_IO_SUPPORTED 714 #ifdef PNG_ERROR_NUMBERS_SUPPORTED 715 /* Check on NULL only added in 1.5.4 */ 716 if (error_message != NULL && *error_message == PNG_LITERAL_SHARP) 717 { 718 /* Strip "#nnnn " from beginning of error message. */ 719 int offset; 720 char error_number[16]; 721 for (offset = 0; offset<15; offset++) 722 { 723 error_number[offset] = error_message[offset + 1]; 724 if (error_message[offset] == ' ') 725 break; 726 } 727 728 if ((offset > 1) && (offset < 15)) 729 { 730 error_number[offset - 1] = '\0'; 731 fprintf(stderr, "libpng error no. %s: %s", 732 error_number, error_message + offset + 1); 733 fprintf(stderr, PNG_STRING_NEWLINE); 734 } 735 736 else 737 { 738 fprintf(stderr, "libpng error: %s, offset=%d", 739 error_message, offset); 740 fprintf(stderr, PNG_STRING_NEWLINE); 741 } 742 } 743 else 744 #endif 745 { 746 fprintf(stderr, "libpng error: %s", error_message ? error_message : 747 "undefined"); 748 fprintf(stderr, PNG_STRING_NEWLINE); 749 } 750 #else 751 PNG_UNUSED(error_message) /* Make compiler happy */ 752 #endif 753 png_longjmp(png_ptr, 1); 754 } 755 756 PNG_FUNCTION(void,PNGAPI 757 png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN) 758 { 759 #ifdef PNG_SETJMP_SUPPORTED 760 if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr) 761 png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val); 762 #endif 763 764 /* If control reaches this point, png_longjmp() must not return. The only 765 * choice is to terminate the whole process (or maybe the thread); to do 766 * this the ANSI-C abort() function is used unless a different method is 767 * implemented by overriding the default configuration setting for 768 * PNG_ABORT(). 769 */ 770 PNG_ABORT(); 771 } 772 773 #ifdef PNG_WARNINGS_SUPPORTED 774 /* This function is called when there is a warning, but the library thinks 775 * it can continue anyway. Replacement functions don't have to do anything 776 * here if you don't want them to. In the default configuration, png_ptr is 777 * not used, but it is passed in case it may be useful. 778 */ 779 static void /* PRIVATE */ 780 png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message) 781 { 782 #ifdef PNG_CONSOLE_IO_SUPPORTED 783 # ifdef PNG_ERROR_NUMBERS_SUPPORTED 784 if (*warning_message == PNG_LITERAL_SHARP) 785 { 786 int offset; 787 char warning_number[16]; 788 for (offset = 0; offset < 15; offset++) 789 { 790 warning_number[offset] = warning_message[offset + 1]; 791 if (warning_message[offset] == ' ') 792 break; 793 } 794 795 if ((offset > 1) && (offset < 15)) 796 { 797 warning_number[offset + 1] = '\0'; 798 fprintf(stderr, "libpng warning no. %s: %s", 799 warning_number, warning_message + offset); 800 fprintf(stderr, PNG_STRING_NEWLINE); 801 } 802 803 else 804 { 805 fprintf(stderr, "libpng warning: %s", 806 warning_message); 807 fprintf(stderr, PNG_STRING_NEWLINE); 808 } 809 } 810 else 811 # endif 812 813 { 814 fprintf(stderr, "libpng warning: %s", warning_message); 815 fprintf(stderr, PNG_STRING_NEWLINE); 816 } 817 #else 818 PNG_UNUSED(warning_message) /* Make compiler happy */ 819 #endif 820 PNG_UNUSED(png_ptr) /* Make compiler happy */ 821 } 822 #endif /* PNG_WARNINGS_SUPPORTED */ 823 824 /* This function is called when the application wants to use another method 825 * of handling errors and warnings. Note that the error function MUST NOT 826 * return to the calling routine or serious problems will occur. The return 827 * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1) 828 */ 829 void PNGAPI 830 png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr, 831 png_error_ptr error_fn, png_error_ptr warning_fn) 832 { 833 if (png_ptr == NULL) 834 return; 835 836 png_ptr->error_ptr = error_ptr; 837 png_ptr->error_fn = error_fn; 838 #ifdef PNG_WARNINGS_SUPPORTED 839 png_ptr->warning_fn = warning_fn; 840 #else 841 PNG_UNUSED(warning_fn) 842 #endif 843 } 844 845 846 /* This function returns a pointer to the error_ptr associated with the user 847 * functions. The application should free any memory associated with this 848 * pointer before png_write_destroy and png_read_destroy are called. 849 */ 850 png_voidp PNGAPI 851 png_get_error_ptr(png_const_structrp png_ptr) 852 { 853 if (png_ptr == NULL) 854 return NULL; 855 856 return ((png_voidp)png_ptr->error_ptr); 857 } 858 859 860 #ifdef PNG_ERROR_NUMBERS_SUPPORTED 861 void PNGAPI 862 png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode) 863 { 864 if (png_ptr != NULL) 865 { 866 png_ptr->flags &= 867 ((~(PNG_FLAG_STRIP_ERROR_NUMBERS | 868 PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode); 869 } 870 } 871 #endif 872 873 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ 874 defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) 875 /* Currently the above both depend on SETJMP_SUPPORTED, however it would be 876 * possible to implement without setjmp support just so long as there is some 877 * way to handle the error return here: 878 */ 879 PNG_FUNCTION(void /* PRIVATE */, (PNGCBAPI 880 png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message), 881 PNG_NORETURN) 882 { 883 const png_const_structrp png_ptr = png_nonconst_ptr; 884 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); 885 886 /* An error is always logged here, overwriting anything (typically a warning) 887 * that is already there: 888 */ 889 if (image != NULL) 890 { 891 png_safecat(image->message, (sizeof image->message), 0, error_message); 892 image->warning_or_error |= PNG_IMAGE_ERROR; 893 894 /* Retrieve the jmp_buf from within the png_control, making this work for 895 * C++ compilation too is pretty tricky: C++ wants a pointer to the first 896 * element of a jmp_buf, but C doesn't tell us the type of that. 897 */ 898 if (image->opaque != NULL && image->opaque->error_buf != NULL) 899 longjmp(png_control_jmp_buf(image->opaque), 1); 900 901 /* Missing longjmp buffer, the following is to help debugging: */ 902 { 903 size_t pos = png_safecat(image->message, (sizeof image->message), 0, 904 "bad longjmp: "); 905 png_safecat(image->message, (sizeof image->message), pos, 906 error_message); 907 } 908 } 909 910 /* Here on an internal programming error. */ 911 abort(); 912 } 913 914 #ifdef PNG_WARNINGS_SUPPORTED 915 void /* PRIVATE */ PNGCBAPI 916 png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message) 917 { 918 const png_const_structrp png_ptr = png_nonconst_ptr; 919 png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); 920 921 /* A warning is only logged if there is no prior warning or error. */ 922 if (image->warning_or_error == 0) 923 { 924 png_safecat(image->message, (sizeof image->message), 0, warning_message); 925 image->warning_or_error |= PNG_IMAGE_WARNING; 926 } 927 } 928 #endif 929 930 int /* PRIVATE */ 931 png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg) 932 { 933 volatile png_imagep image = image_in; 934 volatile int result; 935 volatile png_voidp saved_error_buf; 936 jmp_buf safe_jmpbuf; 937 938 /* Safely execute function(arg) with png_error returning to this function. */ 939 saved_error_buf = image->opaque->error_buf; 940 result = setjmp(safe_jmpbuf) == 0; 941 942 if (result) 943 { 944 945 image->opaque->error_buf = safe_jmpbuf; 946 result = function(arg); 947 } 948 949 image->opaque->error_buf = saved_error_buf; 950 951 /* And do the cleanup prior to any failure return. */ 952 if (!result) 953 png_image_free(image); 954 955 return result; 956 } 957 #endif /* SIMPLIFIED READ/WRITE */ 958 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */ 959
