/* pngerror.c - stub functions for i/o and memory allocation
*
* Copyright (c) 2018-2024 Cosmin Truta
* Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
* Copyright (c) 1996-1997 Andreas Dilger
* 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 /* PRIVATE */,
png_default_error,(png_const_structrp png_ptr, png_const_charp error_message),
PNG_NORETURN);
#ifdef PNG_WARNINGS_SUPPORTED
static void /* PRIVATE */
png_default_warning(png_const_structrp png_ptr,
png_const_charp warning_message);
#endif /* WARNINGS */
/* 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)) != 0)
{
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) != 0)
{
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) != 0)
{
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 /* ERROR_TEXT */
/* 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 != 0 || number % 10 != 0)
{
*--end = digits[number % 10];
output = 1;
}
number /= 10;
break;
case PNG_NUMBER_FORMAT_02u:
/* Expects at least 2 digits. */
mincount = 2;
/* FALLTHROUGH */
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;
/* FALLTHROUGH */
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) && (count == 5) && (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 != 0)
*--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)) != 0)
#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] = {0};
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] = {0};
/* 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 /* WARNINGS */
#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) != 0)
{
# 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);
}
# ifndef PNG_ERROR_TEXT_SUPPORTED
PNG_UNUSED(error_message)
# endif
}
void /* PRIVATE */
png_app_warning(png_const_structrp png_ptr, png_const_charp error_message)
{
if ((png_ptr->flags & PNG_FLAG_APP_WARNINGS_WARN) != 0)
png_warning(png_ptr, error_message);
else
png_error(png_ptr, error_message);
# ifndef PNG_ERROR_TEXT_SUPPORTED
PNG_UNUSED(error_message)
# endif
}
void /* PRIVATE */
png_app_error(png_const_structrp png_ptr, png_const_charp error_message)
{
if ((png_ptr->flags & PNG_FLAG_APP_ERRORS_WARN) != 0)
png_warning(png_ptr, error_message);
else
png_error(png_ptr, error_message);
# ifndef PNG_ERROR_TEXT_SUPPORTED
PNG_UNUSED(error_message)
# endif
}
#endif /* BENIGN_ERRORS */
#define PNG_MAX_ERROR_TEXT 196 /* Currently limited by profile_error in png.c */
#if defined(PNG_WARNINGS_SUPPORTED) || \
(defined(PNG_READ_SUPPORTED) && defined(PNG_ERROR_TEXT_SUPPORTED))
/* 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,
* which 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 const char png_digit[16] = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F'
};
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) != 0)
{
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 /* WARNINGS || ERROR_TEXT */
#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 /* READ && ERROR_TEXT */
#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 /* WARNINGS */
#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) != 0)
png_chunk_warning(png_ptr, error_message);
else
png_chunk_error(png_ptr, error_message);
# ifndef PNG_ERROR_TEXT_SUPPORTED
PNG_UNUSED(error_message)
# endif
}
#endif
#endif /* READ */
void /* PRIVATE */
png_chunk_report(png_const_structrp png_ptr, png_const_charp message, int error)
{
# ifndef PNG_WARNINGS_SUPPORTED
PNG_UNUSED(message)
# endif
/* 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) != 0)
# 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) == 0)
# 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)
unsigned 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 != NULL && png_ptr->longjmp_fn != NULL &&
png_ptr->jmp_buf_ptr != NULL)
png_ptr->longjmp_fn(*png_ptr->jmp_buf_ptr, val);
#else
PNG_UNUSED(png_ptr)
PNG_UNUSED(val)
#endif
/* If control reaches this point, png_longjmp() must not return. The only
* choice is to terminate the whole process (or maybe the thread); to do
* this the ANSI-C abort() function is used unless a different method is
* implemented by overriding the default configuration setting for
* PNG_ABORT().
*/
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 /* WARNINGS */
/* 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 */, (PNGCBAPI
png_safe_error),(png_structp png_nonconst_ptr, png_const_charp error_message),
PNG_NORETURN)
{
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 */ PNGCBAPI
png_safe_warning(png_structp png_nonconst_ptr, png_const_charp warning_message)
{
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, int (*function)(png_voidp), png_voidp arg)
{
const png_voidp saved_error_buf = image->opaque->error_buf;
jmp_buf safe_jmpbuf;
/* Safely execute function(arg), with png_error returning back here. */
if (setjmp(safe_jmpbuf) == 0)
{
int result;
image->opaque->error_buf = safe_jmpbuf;
result = function(arg);
image->opaque->error_buf = saved_error_buf;
if (result)
return 1; /* success */
}
/* The function failed either because of a caught png_error and a regular
* return of false above or because of an uncaught png_error from the
* function itself. Ensure that the error_buf is always set back to the
* value saved above:
*/
image->opaque->error_buf = saved_error_buf;
/* On the final false return, when about to return control to the caller, the
* image is freed (png_image_free does this check but it is duplicated here
* for clarity:
*/
if (saved_error_buf == NULL)
png_image_free(image);
return 0; /* failure */
}
#endif /* SIMPLIFIED READ || SIMPLIFIED_WRITE */
#endif /* READ || WRITE */