1 2 /* pngerror.c - stub functions for i/o and memory allocation 3 * 4 * Last changed in libpng 1.6.24 [August 4, 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 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 */ 964
