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dev: Make the use of stdio FILE robust. #622

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dev: Make the use of stdio FILE robust. #622

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90 changes: 81 additions & 9 deletions png.c
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Original file line number Diff line number Diff line change
Expand Up @@ -669,26 +669,99 @@ png_get_io_ptr(png_const_structrp png_ptr)
return png_ptr->io_ptr;
}

#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
#if defined(PNG_SEQUENTIAL_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
# ifdef PNG_STDIO_SUPPORTED
/* Initialize the default input/output functions for the PNG file. If you
* use your own read or write routines, you can call either png_set_read_fn()
* or png_set_write_fn() instead of png_init_io(). If you have defined
* PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
* function of your own because "FILE *" isn't necessarily available.
*/
void PNGAPI
png_init_io(png_structrp png_ptr, png_FILE_p fp)
void PNGAPI (
png_init_io)(png_structrp png_ptr, FILE *fp,
size_t (*fread)(void *ptr, size_t size, size_t nmemb, FILE*),
size_t (*fwrite)(const void *ptr, size_t size, size_t nmemb, FILE*),
int (*fflush)(FILE*))
{
png_debug(1, "in png_init_io");

if (png_ptr == NULL)
return;

png_ptr->io_ptr = (png_voidp)fp;
}
/* If SEQUENTIAL_READ is not supported and this IS a read png_struct
* png_init_io cannot be used (or, rather, it will not work). Detect this
* early.
*/
# ifndef PNG_SEQUENTIAL_READ_SUPPORTED
/* Read must be done using the progressive reader therefore: */
if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
{
png_app_error(png_ptr, "API: IO cannot be set with progressive read");
return;
}
# endif /* !SEQUENTIAL_READ */

/* First clear out any read/write functionality set by the caller. */
png_ptr->io_ptr = NULL;
# ifdef PNG_READ_SUPPORTED
png_ptr->read_data_fn = NULL;
# endif /* READ */
# ifdef PNG_WRITE_SUPPORTED
png_ptr->write_data_fn = NULL;
# endif /* WRITE */
# ifdef PNG_WRITE_FLUSH_SUPPPORTED
png_ptr->output_flush_fn = NULL;
# endif

/* Set up the stdio based read or write functions as appropriate. */
# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
if ((png_ptr->mode & PNG_IS_READ_STRUCT) != 0)
{
png_ptr->fread = fread;
png_ptr->read_data_fn = png_stdio_read;
}
else
{
png_ptr->fread = NULL;
}
# else /* !SEQUENTIAL_READ */
PNG_UNUSED(fread)
# endif /* !SEQUENTIAL_READ */

# ifdef PNG_WRITE_SUPPORTED
if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
{
png_ptr->fwrite = fwrite;
png_ptr->write_data_fn = png_stdio_write;
}
else
{
png_ptr->fwrite = NULL;
}
# else /* !WRITE */
PNG_UNUSED(fwrite)
# endif /* !WRITE */

# ifdef PNG_WRITE_FLUSH_SUPPORTED
if ((png_ptr->mode & PNG_IS_READ_STRUCT) == 0)
{
png_ptr->fflush = fflush;
png_ptr->output_flush_fn = png_stdio_flush;
}
else
{
png_ptr->fflush = NULL;
}
# else /* !WRITE_FLUSH */
PNG_UNUSED(fflush)
# endif /* !WRITE_FLUSH */

png_ptr->stdio_ptr = fp;
}
# endif /* STDIO */
#endif /* SEQUENTIAL_READ || WRITE */

#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
# ifdef PNG_SAVE_INT_32_SUPPORTED
/* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90
* defines a cast of a signed integer to an unsigned integer either to preserve
Expand Down Expand Up @@ -4556,15 +4629,14 @@ png_image_free_function(png_voidp argument)

/* First free any data held in the control structure. */
# ifdef PNG_STDIO_SUPPORTED
if (cp->owned_file != 0)
if (cp->io_file != NULL)
{
FILE *fp = png_voidcast(FILE*, cp->png_ptr->io_ptr);
cp->owned_file = 0;
FILE *fp = cp->io_file;

/* Ignore errors here. */
if (fp != NULL)
{
cp->png_ptr->io_ptr = NULL;
cp->io_file = NULL;
(void)fclose(fp);
}
}
Expand Down
27 changes: 22 additions & 5 deletions png.h
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Expand Up @@ -1541,9 +1541,17 @@ PNG_REMOVED(209, void, png_set_filter_heuristics_fixed,
*/

#ifdef PNG_STDIO_SUPPORTED
/* Initialize the input/output for the PNG file to the default functions. */
PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, png_FILE_p fp));
#endif
# if defined(PNG_SEQUENTIAL_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
/* Initialize the input/output for the PNG file to use stdio. */
PNG_EXPORT(74, void, png_init_io, (png_structrp png_ptr, FILE *fp,
size_t (*fread)(void *ptr, size_t size, size_t nmemb, FILE*),
size_t (*fwrite)(const void *ptr, size_t size, size_t nmemb, FILE*),
int (*fflush)(FILE*)));

#define png_init_io(png_ptr, fp)\
((png_init_io)(png_ptr, fp, fread, fwrite, fflush))
#endif /* SEQUENTIAL_READ || WRITE */
#endif /* STDIO */

/* Replace the (error and abort), and warning functions with user
* supplied functions. If no messages are to be printed you must still
Expand Down Expand Up @@ -2977,7 +2985,10 @@ PNG_EXPORT(234, int, png_image_begin_read_from_file, (png_imagep image,
*/

PNG_EXPORT(235, int, png_image_begin_read_from_stdio, (png_imagep image,
FILE* file));
FILE* file, size_t (*fread)(void *ptr, size_t size, size_t nmemb, FILE*)));
#define png_image_begin_read_from_stdio(image, file)\
((png_image_begin_read_from_stdio)(image, file, fread))

/* The PNG header is read from the stdio FILE object. */
#endif /* STDIO */

Expand Down Expand Up @@ -3051,8 +3062,14 @@ PNG_EXPORT(239, int, png_image_write_to_file, (png_imagep image,

PNG_EXPORT(240, int, png_image_write_to_stdio, (png_imagep image, FILE *file,
int convert_to_8_bit, const void *buffer, png_int_32 row_stride,
const void *colormap));
const void *colormap,
size_t (*fwrite)(const void *ptr, size_t size, size_t nmemb, FILE*),
int (*fflush)(FILE*)));
/* Write the image to the given (FILE*). */

#define png_image_write_to_stdio(png_ptr, fp, cmap, cvt_to_8, buffer, stride)\
((png_image_write_to_stdio)(png_ptr, fp, cmap, cvt_to_8, buffer, stride,\
fwrite, fflush))
#endif /* SIMPLIFIED_WRITE_STDIO */

/* With all write APIs if image is in one of the linear formats with 16-bit
Expand Down
27 changes: 17 additions & 10 deletions pngpriv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -849,23 +849,27 @@ PNG_INTERNAL_FUNCTION(void,png_zfree,(voidpf png_ptr, voidpf ptr),PNG_EMPTY);
* PNGCBAPI at 1.5.0
*/

PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_read_data,(png_structp png_ptr,
png_bytep data, size_t length),PNG_EMPTY);

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_push_fill_buffer,(png_structp png_ptr,
png_bytep buffer, size_t length),PNG_EMPTY);
#endif
#endif /* PROGRESSIVE_READ */

PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_write_data,(png_structp png_ptr,
#ifdef PNG_STDIO_SUPPORTED
# ifdef PNG_SEQUENTIAL_READ_SUPPORTED
PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_stdio_read,(png_structp png_ptr,
png_bytep data, size_t length),PNG_EMPTY);
# endif /* SEQUENTIAL_READ */

#ifdef PNG_WRITE_SUPPORTED
PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_stdio_write,(png_structp png_ptr,
png_bytep data, size_t length),PNG_EMPTY);
#endif /* WRITE */

#ifdef PNG_WRITE_FLUSH_SUPPORTED
# ifdef PNG_STDIO_SUPPORTED
PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_default_flush,(png_structp png_ptr),
PNG_INTERNAL_FUNCTION(void PNGCBAPI,png_stdio_flush,(png_structp png_ptr),
PNG_EMPTY);
# endif
#endif
#endif /* WRITE_FLUSH */
#endif /* STDIO */

/* Reset the CRC variable */
PNG_INTERNAL_FUNCTION(void,png_reset_crc,(png_structrp png_ptr),PNG_EMPTY);
Expand Down Expand Up @@ -1815,8 +1819,11 @@ typedef struct png_control
png_const_bytep memory; /* Memory buffer. */
size_t size; /* Size of the memory buffer. */

# ifdef PNG_STDIO_SUPPORTED
FILE *io_file; /* FILE* opened by us, not user/app */
# endif

unsigned int for_write :1; /* Otherwise it is a read structure */
unsigned int owned_file :1; /* We own the file in io_ptr */
} png_control;

/* Return the pointer to the jmp_buf from a png_control: necessary because C
Expand Down
58 changes: 31 additions & 27 deletions pngread.c
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Original file line number Diff line number Diff line change
Expand Up @@ -75,12 +75,6 @@ png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
if (png_ptr->target_state != 0U)
png_set_option(png_ptr, PNG_TARGET_SPECIFIC_CODE, 1);
# endif

/* TODO: delay this, it can be done in png_init_io (if the app doesn't
* do it itself) avoiding setting the default function if it is not
* required.
*/
png_set_read_fn(png_ptr, NULL, NULL);
}

return png_ptr;
Expand Down Expand Up @@ -1486,21 +1480,38 @@ png_image_read_header(png_voidp argument)
}

#ifdef PNG_STDIO_SUPPORTED
int PNGAPI
png_image_begin_read_from_stdio(png_imagep image, FILE* file)
typedef struct
{
png_structrp png_ptr;
FILE *file;
size_t (*fread)(void *ptr, size_t size, size_t nmemb, FILE*);
} stdio_read_setup;

static int
setup_stdio_for_read(png_voidp parm)
{
stdio_read_setup *read = png_voidcast(stdio_read_setup*, parm);
(png_init_io)(read->png_ptr, read->file, read->fread, NULL, NULL);
return 1;
}

int PNGAPI (
png_image_begin_read_from_stdio)(png_imagep image, FILE* file,
size_t (*fread)(void *ptr, size_t size, size_t nmemb, FILE*))
{
if (image != NULL && image->version == PNG_IMAGE_VERSION)
{
if (file != NULL)
{
if (png_image_read_init(image) != 0)
if (png_image_read_init(image))
{
/* This is slightly evil, but png_init_io doesn't do anything other
* than this and we haven't changed the standard IO functions so
* this saves a 'safe' function.
*/
image->opaque->png_ptr->io_ptr = file;
return png_safe_execute(image, png_image_read_header, image);
stdio_read_setup parm;
parm.png_ptr = image->opaque->png_ptr;
parm.file = file;
parm.fread = fread;

return png_safe_execute(image, setup_stdio_for_read, &parm) &&
png_safe_execute(image, png_image_read_header, image);
}
}

Expand All @@ -1523,20 +1534,13 @@ png_image_begin_read_from_file(png_imagep image, const char *file_name)
{
if (file_name != NULL)
{
FILE *fp = fopen(file_name, "rb");
/* The file is stored in png_control::io_file and this means that it
* will passed to fclose on error:
*/
FILE* fp = image->opaque->io_file = fopen(file_name, "rb");

if (fp != NULL)
{
if (png_image_read_init(image) != 0)
{
image->opaque->png_ptr->io_ptr = fp;
image->opaque->owned_file = 1;
return png_safe_execute(image, png_image_read_header, image);
}

/* Clean up: just the opened file. */
(void)fclose(fp);
}
return png_image_begin_read_from_stdio(image, fp);

else
return png_image_error(image, strerror(errno));
Expand Down
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