/* pngerror.c - stub functions for i/o and memory allocation * * Last changed in libpng 1.6.1 [March 28, 2013] * Copyright (c) 1998-2013 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h * * This file provides a location for all error handling. Users who * need special error handling are expected to write replacement functions * and use png_set_error_fn() to use those functions. See the instructions * at each function. */ #include "pngpriv.h" #if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) static PNG_FUNCTION(void, png_default_error,PNGARG((png_const_structrp png_ptr, png_const_charp error_message)),PNG_NORETURN); #ifdef PNG_WARNINGS_SUPPORTED static void /* PRIVATE */ png_default_warning PNGARG((png_const_structrp png_ptr, png_const_charp warning_message)); #endif /* PNG_WARNINGS_SUPPORTED */ /* This function is called whenever there is a fatal error. This function * should not be changed. If there is a need to handle errors differently, * you should supply a replacement error function and use png_set_error_fn() * to replace the error function at run-time. */ #ifdef PNG_ERROR_TEXT_SUPPORTED PNG_FUNCTION(void,PNGAPI png_error,(png_const_structrp png_ptr, png_const_charp error_message), PNG_NORETURN) { #ifdef PNG_ERROR_NUMBERS_SUPPORTED char msg[16]; if (png_ptr != NULL) { if (png_ptr->flags& (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) { if (*error_message == PNG_LITERAL_SHARP) { /* Strip "#nnnn " from beginning of error message. */ int offset; for (offset = 1; offset<15; offset++) if (error_message[offset] == ' ') break; if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT) { int i; for (i = 0; i < offset - 1; i++) msg[i] = error_message[i + 1]; msg[i - 1] = '\0'; error_message = msg; } else error_message += offset; } else { if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT) { msg[0] = '0'; msg[1] = '\0'; error_message = msg; } } } } #endif if (png_ptr != NULL && png_ptr->error_fn != NULL) (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), error_message); /* If the custom handler doesn't exist, or if it returns, use the default handler, which will not return. */ png_default_error(png_ptr, error_message); } #else PNG_FUNCTION(void,PNGAPI png_err,(png_const_structrp png_ptr),PNG_NORETURN) { /* Prior to 1.5.2 the error_fn received a NULL pointer, expressed * erroneously as '\0', instead of the empty string "". This was * apparently an error, introduced in libpng-1.2.20, and png_default_error * will crash in this case. */ if (png_ptr != NULL && png_ptr->error_fn != NULL) (*(png_ptr->error_fn))(png_constcast(png_structrp,png_ptr), ""); /* If the custom handler doesn't exist, or if it returns, use the default handler, which will not return. */ png_default_error(png_ptr, ""); } #endif /* PNG_ERROR_TEXT_SUPPORTED */ /* Utility to safely appends strings to a buffer. This never errors out so * error checking is not required in the caller. */ size_t png_safecat(png_charp buffer, size_t bufsize, size_t pos, png_const_charp string) { if (buffer != NULL && pos < bufsize) { if (string != NULL) while (*string != '\0' && pos < bufsize-1) buffer[pos++] = *string++; buffer[pos] = '\0'; } return pos; } #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_TIME_RFC1123_SUPPORTED) /* Utility to dump an unsigned value into a buffer, given a start pointer and * and end pointer (which should point just *beyond* the end of the buffer!) * Returns the pointer to the start of the formatted string. */ png_charp png_format_number(png_const_charp start, png_charp end, int format, png_alloc_size_t number) { int count = 0; /* number of digits output */ int mincount = 1; /* minimum number required */ int output = 0; /* digit output (for the fixed point format) */ *--end = '\0'; /* This is written so that the loop always runs at least once, even with * number zero. */ while (end > start && (number != 0 || count < mincount)) { static const char digits[] = "0123456789ABCDEF"; switch (format) { case PNG_NUMBER_FORMAT_fixed: /* Needs five digits (the fraction) */ mincount = 5; if (output || number % 10 != 0) { *--end = digits[number % 10]; output = 1; } number /= 10; break; case PNG_NUMBER_FORMAT_02u: /* Expects at least 2 digits. */ mincount = 2; /* FALL THROUGH */ case PNG_NUMBER_FORMAT_u: *--end = digits[number % 10]; number /= 10; break; case PNG_NUMBER_FORMAT_02x: /* This format expects at least two digits */ mincount = 2; /* FALL THROUGH */ case PNG_NUMBER_FORMAT_x: *--end = digits[number & 0xf]; number >>= 4; break; default: /* an error */ number = 0; break; } /* Keep track of the number of digits added */ ++count; /* Float a fixed number here: */ if (format == PNG_NUMBER_FORMAT_fixed) if (count == 5) if (end > start) { /* End of the fraction, but maybe nothing was output? In that case * drop the decimal point. If the number is a true zero handle that * here. */ if (output) *--end = '.'; else if (number == 0) /* and !output */ *--end = '0'; } } return end; } #endif #ifdef PNG_WARNINGS_SUPPORTED /* This function is called whenever there is a non-fatal error. This function * should not be changed. If there is a need to handle warnings differently, * you should supply a replacement warning function and use * png_set_error_fn() to replace the warning function at run-time. */ void PNGAPI png_warning(png_const_structrp png_ptr, png_const_charp warning_message) { int offset = 0; if (png_ptr != NULL) { #ifdef PNG_ERROR_NUMBERS_SUPPORTED if (png_ptr->flags& (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT)) #endif { if (*warning_message == PNG_LITERAL_SHARP) { for (offset = 1; offset < 15; offset++) if (warning_message[offset] == ' ') break; } } } if (png_ptr != NULL && png_ptr->warning_fn != NULL) (*(png_ptr->warning_fn))(png_constcast(png_structrp,png_ptr), warning_message + offset); else png_default_warning(png_ptr, warning_message + offset); } /* These functions support 'formatted' warning messages with up to * PNG_WARNING_PARAMETER_COUNT parameters. In the format string the parameter * is introduced by @<number>, where 'number' starts at 1. This follows the * standard established by X/Open for internationalizable error messages. */ void png_warning_parameter(png_warning_parameters p, int number, png_const_charp string) { if (number > 0 && number <= PNG_WARNING_PARAMETER_COUNT) (void)png_safecat(p[number-1], (sizeof p[number-1]), 0, string); } void png_warning_parameter_unsigned(png_warning_parameters p, int number, int format, png_alloc_size_t value) { char buffer[PNG_NUMBER_BUFFER_SIZE]; png_warning_parameter(p, number, PNG_FORMAT_NUMBER(buffer, format, value)); } void png_warning_parameter_signed(png_warning_parameters p, int number, int format, png_int_32 value) { png_alloc_size_t u; png_charp str; char buffer[PNG_NUMBER_BUFFER_SIZE]; /* Avoid overflow by doing the negate in a png_alloc_size_t: */ u = (png_alloc_size_t)value; if (value < 0) u = ~u + 1; str = PNG_FORMAT_NUMBER(buffer, format, u); if (value < 0 && str > buffer) *--str = '-'; png_warning_parameter(p, number, str); } void png_formatted_warning(png_const_structrp png_ptr, png_warning_parameters p, png_const_charp message) { /* The internal buffer is just 192 bytes - enough for all our messages, * overflow doesn't happen because this code checks! If someone figures * out how to send us a message longer than 192 bytes, all that will * happen is that the message will be truncated appropriately. */ size_t i = 0; /* Index in the msg[] buffer: */ char msg[192]; /* Each iteration through the following loop writes at most one character * to msg[i++] then returns here to validate that there is still space for * the trailing '\0'. It may (in the case of a parameter) read more than * one character from message[]; it must check for '\0' and continue to the * test if it finds the end of string. */ while (i<(sizeof msg)-1 && *message != '\0') { /* '@' at end of string is now just printed (previously it was skipped); * it is an error in the calling code to terminate the string with @. */ if (p != NULL && *message == '@' && message[1] != '\0') { int parameter_char = *++message; /* Consume the '@' */ static const char valid_parameters[] = "123456789"; int parameter = 0; /* Search for the parameter digit, the index in the string is the * parameter to use. */ while (valid_parameters[parameter] != parameter_char && valid_parameters[parameter] != '\0') ++parameter; /* If the parameter digit is out of range it will just get printed. */ if (parameter < PNG_WARNING_PARAMETER_COUNT) { /* Append this parameter */ png_const_charp parm = p[parameter]; png_const_charp pend = p[parameter] + (sizeof p[parameter]); /* No need to copy the trailing '\0' here, but there is no guarantee * that parm[] has been initialized, so there is no guarantee of a * trailing '\0': */ while (i<(sizeof msg)-1 && *parm != '\0' && parm < pend) msg[i++] = *parm++; /* Consume the parameter digit too: */ ++message; continue; } /* else not a parameter and there is a character after the @ sign; just * copy that. This is known not to be '\0' because of the test above. */ } /* At this point *message can't be '\0', even in the bad parameter case * above where there is a lone '@' at the end of the message string. */ msg[i++] = *message++; } /* i is always less than (sizeof msg), so: */ msg[i] = '\0'; /* And this is the formatted message. It may be larger than * PNG_MAX_ERROR_TEXT, but that is only used for 'chunk' errors and these * are not (currently) formatted. */ png_warning(png_ptr, msg); } #endif /* PNG_WARNINGS_SUPPORTED */ #ifdef PNG_BENIGN_ERRORS_SUPPORTED void PNGAPI png_benign_error(png_const_structrp png_ptr, png_const_charp error_message) { if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) { # ifdef PNG_READ_SUPPORTED if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && png_ptr->chunk_name != 0) png_chunk_warning(png_ptr, error_message); else # endif png_warning(png_ptr, error_message); } else { # ifdef PNG_READ_SUPPORTED if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0 && png_ptr->chunk_name != 0) png_chunk_error(png_ptr, error_message); else # endif png_error(png_ptr, error_message); } } void /* PRIVATE */ png_app_warning(png_const_structrp png_ptr, png_const_charp error_message) { if (png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) png_warning(png_ptr, error_message); else png_error(png_ptr, error_message); } void /* PRIVATE */ png_app_error(png_const_structrp png_ptr, png_const_charp error_message) { if (png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) png_warning(png_ptr, error_message); else png_error(png_ptr, error_message); } #endif /* BENIGN_ERRORS */ /* These utilities are used internally to build an error message that relates * to the current chunk. The chunk name comes from png_ptr->chunk_name, * this is used to prefix the message. The message is limited in length * to 63 bytes, the name characters are output as hex digits wrapped in [] * if the character is invalid. */ #define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97)) static PNG_CONST char png_digit[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' }; #define PNG_MAX_ERROR_TEXT 196 /* Currently limited be profile_error in png.c */ #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED) static void /* PRIVATE */ png_format_buffer(png_const_structrp png_ptr, png_charp buffer, png_const_charp error_message) { png_uint_32 chunk_name = png_ptr->chunk_name; int iout = 0, ishift = 24; while (ishift >= 0) { int c = (int)(chunk_name >> ishift) & 0xff; ishift -= 8; if (isnonalpha(c)) { buffer[iout++] = PNG_LITERAL_LEFT_SQUARE_BRACKET; buffer[iout++] = png_digit[(c & 0xf0) >> 4]; buffer[iout++] = png_digit[c & 0x0f]; buffer[iout++] = PNG_LITERAL_RIGHT_SQUARE_BRACKET; } else { buffer[iout++] = (char)c; } } if (error_message == NULL) buffer[iout] = '\0'; else { int iin = 0; buffer[iout++] = ':'; buffer[iout++] = ' '; while (iin < PNG_MAX_ERROR_TEXT-1 && error_message[iin] != '\0') buffer[iout++] = error_message[iin++]; /* iin < PNG_MAX_ERROR_TEXT, so the following is safe: */ buffer[iout] = '\0'; } } #endif /* PNG_WARNINGS_SUPPORTED || PNG_ERROR_TEXT_SUPPORTED */ #if defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED) PNG_FUNCTION(void,PNGAPI png_chunk_error,(png_const_structrp png_ptr, png_const_charp error_message), PNG_NORETURN) { char msg[18+PNG_MAX_ERROR_TEXT]; if (png_ptr == NULL) png_error(png_ptr, error_message); else { png_format_buffer(png_ptr, msg, error_message); png_error(png_ptr, msg); } } #endif /* PNG_READ_SUPPORTED && PNG_ERROR_TEXT_SUPPORTED */ #ifdef PNG_WARNINGS_SUPPORTED void PNGAPI png_chunk_warning(png_const_structrp png_ptr, png_const_charp warning_message) { char msg[18+PNG_MAX_ERROR_TEXT]; if (png_ptr == NULL) png_warning(png_ptr, warning_message); else { png_format_buffer(png_ptr, msg, warning_message); png_warning(png_ptr, msg); } } #endif /* PNG_WARNINGS_SUPPORTED */ #ifdef PNG_READ_SUPPORTED #ifdef PNG_BENIGN_ERRORS_SUPPORTED void PNGAPI png_chunk_benign_error(png_const_structrp png_ptr, png_const_charp error_message) { if (png_ptr->flags & PNG_FLAG_BENIGN_ERRORS_WARN) png_chunk_warning(png_ptr, error_message); else png_chunk_error(png_ptr, error_message); } #endif #endif /* PNG_READ_SUPPORTED */ void /* PRIVATE */ png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error) { /* This is always supported, but for just read or just write it * unconditionally does the right thing. */ # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) if (png_ptr->mode & PNG_IS_READ_STRUCT) # endif # ifdef PNG_READ_SUPPORTED { if (error < PNG_CHUNK_ERROR) png_chunk_warning(png_ptr, message); else png_chunk_benign_error(png_ptr, message); } # endif # if defined(PNG_READ_SUPPORTED) && defined(PNG_WRITE_SUPPORTED) else if (!(png_ptr->mode & PNG_IS_READ_STRUCT)) # endif # ifdef PNG_WRITE_SUPPORTED { if (error < PNG_CHUNK_WRITE_ERROR) png_app_warning(png_ptr, message); else png_app_error(png_ptr, message); } # endif } #ifdef PNG_ERROR_TEXT_SUPPORTED #ifdef PNG_FLOATING_POINT_SUPPORTED PNG_FUNCTION(void, png_fixed_error,(png_const_structrp png_ptr, png_const_charp name),PNG_NORETURN) { # define fixed_message "fixed point overflow in " # define fixed_message_ln ((sizeof fixed_message)-1) int iin; char msg[fixed_message_ln+PNG_MAX_ERROR_TEXT]; memcpy(msg, fixed_message, fixed_message_ln); iin = 0; if (name != NULL) while (iin < (PNG_MAX_ERROR_TEXT-1) && name[iin] != 0) { msg[fixed_message_ln + iin] = name[iin]; ++iin; } msg[fixed_message_ln + iin] = 0; png_error(png_ptr, msg); } #endif #endif #ifdef PNG_SETJMP_SUPPORTED /* This API only exists if ANSI-C style error handling is used, * otherwise it is necessary for png_default_error to be overridden. */ jmp_buf* PNGAPI png_set_longjmp_fn(png_structrp png_ptr, png_longjmp_ptr longjmp_fn, size_t jmp_buf_size) { /* From libpng 1.6.0 the app gets one chance to set a 'jmpbuf_size' value * and it must not change after that. Libpng doesn't care how big the * buffer is, just that it doesn't change. * * If the buffer size is no *larger* than the size of jmp_buf when libpng is * compiled a built in jmp_buf is returned; this preserves the pre-1.6.0 * semantics that this call will not fail. If the size is larger, however, * the buffer is allocated and this may fail, causing the function to return * NULL. */ if (png_ptr == NULL) return NULL; if (png_ptr->jmp_buf_ptr == NULL) { png_ptr->jmp_buf_size = 0; /* not allocated */ if (jmp_buf_size <= (sizeof png_ptr->jmp_buf_local)) png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; else { png_ptr->jmp_buf_ptr = png_voidcast(jmp_buf *, png_malloc_warn(png_ptr, jmp_buf_size)); if (png_ptr->jmp_buf_ptr == NULL) return NULL; /* new NULL return on OOM */ png_ptr->jmp_buf_size = jmp_buf_size; } } else /* Already allocated: check the size */ { size_t size = png_ptr->jmp_buf_size; if (size == 0) { size = (sizeof png_ptr->jmp_buf_local); if (png_ptr->jmp_buf_ptr != &png_ptr->jmp_buf_local) { /* This is an internal error in libpng: somehow we have been left * with a stack allocated jmp_buf when the application regained * control. It's always possible to fix this up, but for the moment * this is a png_error because that makes it easy to detect. */ png_error(png_ptr, "Libpng jmp_buf still allocated"); /* png_ptr->jmp_buf_ptr = &png_ptr->jmp_buf_local; */ } } if (size != jmp_buf_size) { png_warning(png_ptr, "Application jmp_buf size changed"); return NULL; /* caller will probably crash: no choice here */ } } /* Finally fill in the function, now we have a satisfactory buffer. It is * valid to change the function on every call. */ png_ptr->longjmp_fn = longjmp_fn; return png_ptr->jmp_buf_ptr; } void /* PRIVATE */ png_free_jmpbuf(png_structrp png_ptr) { if (png_ptr != NULL) { jmp_buf *jb = png_ptr->jmp_buf_ptr; /* A size of 0 is used to indicate a local, stack, allocation of the * pointer; used here and in png.c */ if (jb != NULL && png_ptr->jmp_buf_size > 0) { /* This stuff is so that a failure to free the error control structure * does not leave libpng in a state with no valid error handling: the * free always succeeds, if there is an error it gets ignored. */ if (jb != &png_ptr->jmp_buf_local) { /* Make an internal, libpng, jmp_buf to return here */ jmp_buf free_jmp_buf; if (!setjmp(free_jmp_buf)) { png_ptr->jmp_buf_ptr = &free_jmp_buf; /* come back here */ png_ptr->jmp_buf_size = 0; /* stack allocation */ png_ptr->longjmp_fn = longjmp; png_free(png_ptr, jb); /* Return to setjmp on error */ } } } /* *Always* cancel everything out: */ png_ptr->jmp_buf_size = 0; png_ptr->jmp_buf_ptr = NULL; png_ptr->longjmp_fn = 0; } } #endif /* This is the default error handling function. Note that replacements for * this function MUST NOT RETURN, or the program will likely crash. This * function is used by default, or if the program supplies NULL for the * error function pointer in png_set_error_fn(). */ static PNG_FUNCTION(void /* PRIVATE */, png_default_error,(png_const_structrp png_ptr, png_const_charp error_message), PNG_NORETURN) { #ifdef PNG_CONSOLE_IO_SUPPORTED #ifdef PNG_ERROR_NUMBERS_SUPPORTED /* Check on NULL only added in 1.5.4 */ if (error_message != NULL && *error_message == PNG_LITERAL_SHARP) { /* Strip "#nnnn " from beginning of error message. */ int offset; char error_number[16]; for (offset = 0; offset<15; offset++) { error_number[offset] = error_message[offset + 1]; if (error_message[offset] == ' ') break; } if ((offset > 1) && (offset < 15)) { error_number[offset - 1] = '\0'; fprintf(stderr, "libpng error no. %s: %s", error_number, error_message + offset + 1); fprintf(stderr, PNG_STRING_NEWLINE); } else { fprintf(stderr, "libpng error: %s, offset=%d", error_message, offset); fprintf(stderr, PNG_STRING_NEWLINE); } } else #endif { fprintf(stderr, "libpng error: %s", error_message ? error_message : "undefined"); fprintf(stderr, PNG_STRING_NEWLINE); } #else PNG_UNUSED(error_message) /* Make compiler happy */ #endif png_longjmp(png_ptr, 1); } PNG_FUNCTION(void,PNGAPI png_longjmp,(png_const_structrp png_ptr, int val),PNG_NORETURN) { #ifdef PNG_SETJMP_SUPPORTED if (png_ptr && png_ptr->longjmp_fn && png_ptr->jmp_buf_ptr) png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val); #endif /* Here if not setjmp support or if png_ptr is null. */ PNG_ABORT(); } #ifdef PNG_WARNINGS_SUPPORTED /* This function is called when there is a warning, but the library thinks * it can continue anyway. Replacement functions don't have to do anything * here if you don't want them to. In the default configuration, png_ptr is * not used, but it is passed in case it may be useful. */ static void /* PRIVATE */ png_default_warning(png_const_structrp png_ptr, png_const_charp warning_message) { #ifdef PNG_CONSOLE_IO_SUPPORTED # ifdef PNG_ERROR_NUMBERS_SUPPORTED if (*warning_message == PNG_LITERAL_SHARP) { int offset; char warning_number[16]; for (offset = 0; offset < 15; offset++) { warning_number[offset] = warning_message[offset + 1]; if (warning_message[offset] == ' ') break; } if ((offset > 1) && (offset < 15)) { warning_number[offset + 1] = '\0'; fprintf(stderr, "libpng warning no. %s: %s", warning_number, warning_message + offset); fprintf(stderr, PNG_STRING_NEWLINE); } else { fprintf(stderr, "libpng warning: %s", warning_message); fprintf(stderr, PNG_STRING_NEWLINE); } } else # endif { fprintf(stderr, "libpng warning: %s", warning_message); fprintf(stderr, PNG_STRING_NEWLINE); } #else PNG_UNUSED(warning_message) /* Make compiler happy */ #endif PNG_UNUSED(png_ptr) /* Make compiler happy */ } #endif /* PNG_WARNINGS_SUPPORTED */ /* This function is called when the application wants to use another method * of handling errors and warnings. Note that the error function MUST NOT * return to the calling routine or serious problems will occur. The return * method used in the default routine calls longjmp(png_ptr->jmp_buf_ptr, 1) */ void PNGAPI png_set_error_fn(png_structrp png_ptr, png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn) { if (png_ptr == NULL) return; png_ptr->error_ptr = error_ptr; png_ptr->error_fn = error_fn; #ifdef PNG_WARNINGS_SUPPORTED png_ptr->warning_fn = warning_fn; #else PNG_UNUSED(warning_fn) #endif } /* This function returns a pointer to the error_ptr associated with the user * functions. The application should free any memory associated with this * pointer before png_write_destroy and png_read_destroy are called. */ png_voidp PNGAPI png_get_error_ptr(png_const_structrp png_ptr) { if (png_ptr == NULL) return NULL; return ((png_voidp)png_ptr->error_ptr); } #ifdef PNG_ERROR_NUMBERS_SUPPORTED void PNGAPI png_set_strip_error_numbers(png_structrp png_ptr, png_uint_32 strip_mode) { if (png_ptr != NULL) { png_ptr->flags &= ((~(PNG_FLAG_STRIP_ERROR_NUMBERS | PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode); } } #endif #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) ||\ defined(PNG_SIMPLIFIED_WRITE_SUPPORTED) /* Currently the above both depend on SETJMP_SUPPORTED, however it would be * possible to implement without setjmp support just so long as there is some * way to handle the error return here: */ PNG_FUNCTION(void /* PRIVATE */, png_safe_error,(png_structp png_nonconst_ptr, png_const_charp error_message), PNG_NORETURN) { const png_const_structrp png_ptr = png_nonconst_ptr; png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); /* An error is always logged here, overwriting anything (typically a warning) * that is already there: */ if (image != NULL) { png_safecat(image->message, (sizeof image->message), 0, error_message); image->warning_or_error |= PNG_IMAGE_ERROR; /* Retrieve the jmp_buf from within the png_control, making this work for * C++ compilation too is pretty tricky: C++ wants a pointer to the first * element of a jmp_buf, but C doesn't tell us the type of that. */ if (image->opaque != NULL && image->opaque->error_buf != NULL) longjmp(png_control_jmp_buf(image->opaque), 1); /* Missing longjmp buffer, the following is to help debugging: */ { size_t pos = png_safecat(image->message, (sizeof image->message), 0, "bad longjmp: "); png_safecat(image->message, (sizeof image->message), pos, error_message); } } /* Here on an internal programming error. */ abort(); } #ifdef PNG_WARNINGS_SUPPORTED void /* PRIVATE */ png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message) { const png_const_structrp png_ptr = png_nonconst_ptr; png_imagep image = png_voidcast(png_imagep, png_ptr->error_ptr); /* A warning is only logged if there is no prior warning or error. */ if (image->warning_or_error == 0) { png_safecat(image->message, (sizeof image->message), 0, warning_message); image->warning_or_error |= PNG_IMAGE_WARNING; } } #endif int /* PRIVATE */ png_safe_execute(png_imagep image_in, int (*function)(png_voidp), png_voidp arg) { volatile png_imagep image = image_in; volatile int result; volatile png_voidp saved_error_buf; jmp_buf safe_jmpbuf; /* Safely execute function(arg) with png_error returning to this function. */ saved_error_buf = image->opaque->error_buf; result = setjmp(safe_jmpbuf) == 0; if (result) { image->opaque->error_buf = safe_jmpbuf; result = function(arg); } image->opaque->error_buf = saved_error_buf; /* And do the cleanup prior to any failure return. */ if (!result) png_image_free(image); return result; } #endif /* SIMPLIFIED READ/WRITE */ #endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */