pngerror.c

   1
   2 /* pngerror.c - stub functions for i/o and memory allocation
   3  *
   4  * Last changed in libpng 1.5.1 [February 3, 2011]
   5  * Copyright (c) 1998-2011 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_structp 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_structp 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_structp png_ptr, png_const_charp error_message),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_ptr, error_message);
  83
  84    /* If the custom handler doesn't exist, or if it returns,
  85       use the default handler, which will not return. */
  86    png_default_error(png_ptr, error_message);
  87 }
  88 #else
  89 PNG_FUNCTION(void,PNGAPI
  90 png_err,(png_structp png_ptr),PNG_NORETURN)
  91 {
  92    if (png_ptr != NULL && png_ptr->error_fn != NULL)
  93       (*(png_ptr->error_fn))(png_ptr, '\0');
  94
  95    /* If the custom handler doesn't exist, or if it returns,
  96       use the default handler, which will not return. */
  97    png_default_error(png_ptr, '\0');
  98 }
  99 #endif /* PNG_ERROR_TEXT_SUPPORTED */
 100
 101 #ifdef PNG_WARNINGS_SUPPORTED
 102 /* This function is called whenever there is a non-fatal error.  This function
 103  * should not be changed.  If there is a need to handle warnings differently,
 104  * you should supply a replacement warning function and use
 105  * png_set_error_fn() to replace the warning function at run-time.
 106  */
 107 void PNGAPI
 108 png_warning(png_structp png_ptr, png_const_charp warning_message)
 109 {
 110    int offset = 0;
 111    if (png_ptr != NULL)
 112    {
 113 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 114    if (png_ptr->flags&
 115        (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
 116 #endif
 117       {
 118          if (*warning_message == PNG_LITERAL_SHARP)
 119          {
 120             for (offset = 1; offset < 15; offset++)
 121                if (warning_message[offset] == ' ')
 122                   break;
 123          }
 124       }
 125    }
 126    if (png_ptr != NULL && png_ptr->warning_fn != NULL)
 127       (*(png_ptr->warning_fn))(png_ptr, warning_message + offset);
 128    else
 129       png_default_warning(png_ptr, warning_message + offset);
 130 }
 131 #endif /* PNG_WARNINGS_SUPPORTED */
 132
 133 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
 134 void PNGAPI
 135 png_benign_error(png_structp png_ptr, png_const_charp error_message)
 136 {
 137   if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
 138      png_warning(png_ptr, error_message);
 139   else
 140      png_error(png_ptr, error_message);
 141 }
 142 #endif
 143
 144 /* These utilities are used internally to build an error message that relates
 145  * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
 146  * this is used to prefix the message.  The message is limited in length
 147  * to 63 bytes, the name characters are output as hex digits wrapped in []
 148  * if the character is invalid.
 149  */
 150 #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
 151 static PNG_CONST char png_digit[16] = {
 152    '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 153    'A', 'B', 'C', 'D', 'E', 'F'
 154 };
 155
 156 #define PNG_MAX_ERROR_TEXT 64
 157 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
 158 static void /* PRIVATE */
 159 png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
 160     error_message)
 161 {
 162    int iout = 0, iin = 0;
 163
 164    while (iin < 4)
 165    {
 166       int c = png_ptr->chunk_name[iin++];
 167       if (isnonalpha(c))
 168       {
 169          buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET;
 170          buffer[iout++] = png_digit[(c & 0xf0) >> 4];
 171          buffer[iout++] = png_digit[c & 0x0f];
 172          buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET;
 173       }
 174
 175       else
 176       {
 177          buffer[iout++] = (png_byte)c;
 178       }
 179    }
 180
 181    if (error_message == NULL)
 182       buffer[iout] = '\0';
 183
 184    else
 185    {
 186       buffer[iout++] = ':';
 187       buffer[iout++] = ' ';
 188       png_memcpy(buffer + iout, error_message, PNG_MAX_ERROR_TEXT);
 189       buffer[iout + PNG_MAX_ERROR_TEXT - 1] = '\0';
 190    }
 191 }
 192 #endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */
 193
 194 #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED)
 195 PNG_FUNCTION(void,PNGAPI
 196 png_chunk_error,(png_structp png_ptr, png_const_charp error_message),
 197    PNG_NORETURN)
 198 {
 199    char msg[18+PNG_MAX_ERROR_TEXT];
 200    if (png_ptr == NULL)
 201       png_error(png_ptr, error_message);
 202
 203    else
 204    {
 205       png_format_buffer(png_ptr, msg, error_message);
 206       png_error(png_ptr, msg);
 207    }
 208 }
 209 #endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */
 210
 211 #ifdef PNG_WARNINGS_SUPPORTED
 212 void PNGAPI
 213 png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
 214 {
 215    char msg[18+PNG_MAX_ERROR_TEXT];
 216    if (png_ptr == NULL)
 217       png_warning(png_ptr, warning_message);
 218
 219    else
 220    {
 221       png_format_buffer(png_ptr, msg, warning_message);
 222       png_warning(png_ptr, msg);
 223    }
 224 }
 225 #endif /* PNG_WARNINGS_SUPPORTED */
 226
 227 #ifdef PNG_READ_SUPPORTED
 228 #ifdef PNG_BENIGN_ERRORS_SUPPORTED
 229 void PNGAPI
 230 png_chunk_benign_error(png_structp png_ptr, png_const_charp error_message)
 231 {
 232    if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN)
 233       png_chunk_warning(png_ptr, error_message);
 234
 235    else
 236       png_chunk_error(png_ptr, error_message);
 237 }
 238 #endif
 239 #endif /* PNG_READ_SUPPORTED */
 240
 241 #ifdef PNG_ERROR_TEXT_SUPPORTED
 242 #ifdef PNG_FLOATING_POINT_SUPPORTED
 243 PNG_FUNCTION(void,
 244 png_fixed_error,(png_structp png_ptr, png_const_charp name),PNG_NORETURN)
 245 {
 246 #  define fixed_message "fixed point overflow in "
 247 #  define fixed_message_ln ((sizeof fixed_message)-1)
 248    int  iin;
 249    char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT];
 250    png_memcpy(msg, fixed_message, fixed_message_ln);
 251    iin = 0;
 252    if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0)
 253    {
 254       msg[fixed_message_ln + iin] = name[iin];
 255       ++iin;
 256    }
 257    msg[fixed_message_ln + iin] = 0;
 258    png_error(png_ptr, msg);
 259 }
 260 #endif
 261 #endif
 262
 263 #ifdef PNG_SETJMP_SUPPORTED
 264 /* This API only exists if ANSI-C style error handling is used,
 265  * otherwise it is necessary for png_default_error to be overridden.
 266  */
 267 jmp_buf* PNGAPI
 268 png_set_longjmp_fn(png_structp png_ptr, png_longjmp_ptr longjmp_fn,
 269     size_t jmp_buf_size)
 270 {
 271    if (png_ptr == NULL || jmp_buf_size != png_sizeof(jmp_buf))
 272       return NULL;
 273
 274    png_ptr->longjmp_fn = longjmp_fn;
 275    return &png_ptr->png_jmpbuf;
 276 }
 277 #endif
 278
 279 /* This is the default error handling function.  Note that replacements for
 280  * this function MUST NOT RETURN, or the program will likely crash.  This
 281  * function is used by default, or if the program supplies NULL for the
 282  * error function pointer in png_set_error_fn().
 283  */
 284 static PNG_FUNCTION(void /* PRIVATE */,
 285 png_default_error,(png_structp png_ptr, png_const_charp error_message),
 286    PNG_NORETURN)
 287 {
 288 #ifdef PNG_CONSOLE_IO_SUPPORTED
 289 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 290    if (*error_message == PNG_LITERAL_SHARP)
 291    {
 292       /* Strip "#nnnn " from beginning of error message. */
 293       int offset;
 294       char error_number[16];
 295       for (offset = 0; offset<15; offset++)
 296       {
 297          error_number[offset] = error_message[offset + 1];
 298          if (error_message[offset] == ' ')
 299             break;
 300       }
 301
 302       if ((offset > 1) && (offset < 15))
 303       {
 304          error_number[offset - 1] = '\0';
 305          fprintf(stderr, "libpng error no. %s: %s",
 306              error_number, error_message + offset + 1);
 307          fprintf(stderr, PNG_STRING_NEWLINE);
 308       }
 309
 310       else
 311       {
 312          fprintf(stderr, "libpng error: %s, offset=%d",
 313              error_message, offset);
 314          fprintf(stderr, PNG_STRING_NEWLINE);
 315       }
 316    }
 317    else
 318 #endif
 319    {
 320       fprintf(stderr, "libpng error: %s", error_message);
 321       fprintf(stderr, PNG_STRING_NEWLINE);
 322    }
 323 #endif
 324 #ifndef PNG_CONSOLE_IO_SUPPORTED
 325    PNG_UNUSED(error_message) /* Make compiler happy */
 326 #endif
 327    png_longjmp(png_ptr, 1);
 328 }
 329
 330 PNG_FUNCTION(void,PNGAPI
 331 png_longjmp,(png_structp png_ptr, int val),PNG_NORETURN)
 332 {
 333 #ifdef PNG_SETJMP_SUPPORTED
 334    if (png_ptr && png_ptr->longjmp_fn)
 335    {
 336 #  ifdef USE_FAR_KEYWORD
 337       {
 338          jmp_buf png_jmpbuf;
 339          png_memcpy(png_jmpbuf, png_ptr->png_jmpbuf, png_sizeof(jmp_buf));
 340          png_ptr->longjmp_fn(png_jmpbuf, val);
 341       }
 342
 343 #  else
 344    png_ptr->longjmp_fn(png_ptr->png_jmpbuf, val);
 345 #  endif
 346    }
 347 #endif
 348    /* Here if not setjmp support or if png_ptr is null. */
 349    PNG_ABORT();
 350 }
 351
 352 #ifdef PNG_WARNINGS_SUPPORTED
 353 /* This function is called when there is a warning, but the library thinks
 354  * it can continue anyway.  Replacement functions don't have to do anything
 355  * here if you don't want them to.  In the default configuration, png_ptr is
 356  * not used, but it is passed in case it may be useful.
 357  */
 358 static void /* PRIVATE */
 359 png_default_warning(png_structp png_ptr, png_const_charp warning_message)
 360 {
 361 #ifdef PNG_CONSOLE_IO_SUPPORTED
 362 #  ifdef PNG_ERROR_NUMBERS_SUPPORTED
 363    if (*warning_message == PNG_LITERAL_SHARP)
 364    {
 365       int offset;
 366       char warning_number[16];
 367       for (offset = 0; offset < 15; offset++)
 368       {
 369          warning_number[offset] = warning_message[offset + 1];
 370          if (warning_message[offset] == ' ')
 371             break;
 372       }
 373
 374       if ((offset > 1) && (offset < 15))
 375       {
 376          warning_number[offset + 1] = '\0';
 377          fprintf(stderr, "libpng warning no. %s: %s",
 378              warning_number, warning_message + offset);
 379          fprintf(stderr, PNG_STRING_NEWLINE);
 380       }
 381
 382       else
 383       {
 384          fprintf(stderr, "libpng warning: %s",
 385              warning_message);
 386          fprintf(stderr, PNG_STRING_NEWLINE);
 387       }
 388    }
 389    else
 390 #  endif
 391
 392    {
 393       fprintf(stderr, "libpng warning: %s", warning_message);
 394       fprintf(stderr, PNG_STRING_NEWLINE);
 395    }
 396 #else
 397    PNG_UNUSED(warning_message) /* Make compiler happy */
 398 #endif
 399    PNG_UNUSED(png_ptr) /* Make compiler happy */
 400 }
 401 #endif /* PNG_WARNINGS_SUPPORTED */
 402
 403 /* This function is called when the application wants to use another method
 404  * of handling errors and warnings.  Note that the error function MUST NOT
 405  * return to the calling routine or serious problems will occur.  The return
 406  * method used in the default routine calls longjmp(png_ptr->png_jmpbuf, 1)
 407  */
 408 void PNGAPI
 409 png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
 410     png_error_ptr error_fn, png_error_ptr warning_fn)
 411 {
 412    if (png_ptr == NULL)
 413       return;
 414
 415    png_ptr->error_ptr = error_ptr;
 416    png_ptr->error_fn = error_fn;
 417    png_ptr->warning_fn = warning_fn;
 418 }
 419
 420
 421 /* This function returns a pointer to the error_ptr associated with the user
 422  * functions.  The application should free any memory associated with this
 423  * pointer before png_write_destroy and png_read_destroy are called.
 424  */
 425 png_voidp PNGAPI
 426 png_get_error_ptr(png_const_structp png_ptr)
 427 {
 428    if (png_ptr == NULL)
 429       return NULL;
 430
 431    return ((png_voidp)png_ptr->error_ptr);
 432 }
 433
 434
 435 #ifdef PNG_ERROR_NUMBERS_SUPPORTED
 436 void PNGAPI
 437 png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
 438 {
 439    if (png_ptr != NULL)
 440    {
 441       png_ptr->flags &=
 442          ((~(PNG_FLAG_STRIP_ERROR_NUMBERS |
 443          PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
 444    }
 445 }
 446 #endif
 447 #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */