| /* png-fix-too-far-back.c |
| * |
| * Copyright (c) 2013 John Cunningham Bowler |
| * |
| * Last changed in libpng 1.6.3 [(PENDING RELEASE)] |
| * |
| * This code is released under the libpng license. |
| * For conditions of distribution and use, see the disclaimer |
| * and license in png.h |
| * |
| * Tool to check and fix the zlib inflate 'too far back' problem, see the usage |
| * message for more information. |
| */ |
| #include <stdlib.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <ctype.h> |
| |
| #define PROGRAM_NAME "png-fix-too-far-back" |
| |
| /* Define the following to use this program against your installed libpng, |
| * rather than the one being built here: |
| */ |
| #ifdef PNG_FREESTANDING_TESTS |
| # include <png.h> |
| #else |
| # include "../../png.h" |
| #endif |
| |
| #if PNG_LIBPNG_VER < 10603 /* 1.6.3 */ |
| # error "png-fix-too-far-back will not work with libpng prior to 1.6.3" |
| #endif |
| |
| #ifdef PNG_READ_SUPPORTED |
| #include <zlib.h> |
| |
| #ifndef PNG_MAXIMUM_INFLATE_WINDOW |
| # error "png-fix-too-far-back not supported in this libpng version" |
| #endif |
| |
| #if PNG_ZLIB_VERNUM >= 0x1240 |
| |
| /* Copied from pngpriv.h */ |
| #ifdef __cplusplus |
| # define png_voidcast(type, value) static_cast<type>(value) |
| # define png_constcast(type, value) const_cast<type>(value) |
| # define png_aligncast(type, value) \ |
| static_cast<type>(static_cast<void*>(value)) |
| # define png_aligncastconst(type, value) \ |
| static_cast<type>(static_cast<const void*>(value)) |
| #else |
| # define png_voidcast(type, value) (value) |
| # define png_constcast(type, value) ((type)(value)) |
| # define png_aligncast(type, value) ((void*)(value)) |
| # define png_aligncastconst(type, value) ((const void*)(value)) |
| #endif /* __cplusplus */ |
| |
| static int idat_error = 0; |
| static int verbose = 0; |
| static int errors = 0; |
| static int warnings = 0; |
| #ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| static int set_option = 0; |
| #endif |
| static const char *name = "stdin"; |
| static uLong crc_IDAT_head; /* CRC32 of "IDAT" */ |
| static uLong crc_IEND; |
| static z_stream z_idat; |
| |
| /* Control structure for the temporary file */ |
| typedef struct |
| { |
| size_t image_size; |
| off_t file_size; |
| fpos_t header_pos; |
| fpos_t crc_pos; |
| uLong crc_tail; /* CRC of bytes after header */ |
| png_uint_32 len_tail; /* Count thereof */ |
| png_byte header[2]; |
| |
| /* Image info */ |
| png_uint_32 width; |
| png_uint_32 height; |
| png_byte bit_depth; |
| png_byte color_type; |
| png_byte compression_method; |
| png_byte filter_method; |
| png_byte interlace_method; |
| } IDAT_info; |
| |
| static png_uint_32 |
| mult(png_uint_32 n, png_uint_32 m) |
| { |
| if ((n + (m-1)) / m > 0xffffffff/m) |
| { |
| fprintf(stderr, "%s: overflow (%lu, %u)\n", name, (unsigned long)n, m); |
| exit(2); |
| } |
| |
| return n * m; |
| } |
| |
| static size_t |
| image_size(const IDAT_info *info) |
| { |
| unsigned int pd = info->bit_depth; |
| size_t cb; |
| |
| switch (info->color_type) |
| { |
| case 0: case 3: |
| break; |
| |
| case 2: /* rgb */ |
| pd *= 3; |
| break; |
| |
| case 4: /* ga */ |
| pd *= 2; |
| break; |
| |
| case 6: /* rgba */ |
| pd *= 4; |
| break; |
| |
| default: |
| fprintf(stderr, "%s: invalid color type (%d)\n", name, |
| info->color_type); |
| exit(2); |
| } |
| |
| switch (info->interlace_method) |
| { |
| case PNG_INTERLACE_ADAM7: |
| /* Interlacing makes the image larger because of the replication of |
| * both the filter byte and the padding to a byte boundary. |
| */ |
| { |
| int pass; |
| |
| for (cb=0, pass=0; pass<=6; ++pass) |
| { |
| png_uint_32 pw = PNG_PASS_COLS(info->width, pass); |
| |
| if (pw > 0) |
| cb += mult(((mult(pd, pw)+7) >> 3)+1, |
| PNG_PASS_ROWS(info->height, pass)); |
| } |
| } |
| break; |
| |
| case PNG_INTERLACE_NONE: |
| cb = mult(info->height, 1+((mult(info->width, pd) + 7) >> 3)); |
| break; |
| |
| default: |
| fprintf(stderr, "%s: invalid interlace type %d\n", name, |
| info->interlace_method); |
| exit(2); |
| } |
| |
| return cb; |
| } |
| |
| static int |
| image_windowBits(const IDAT_info *info) |
| { |
| size_t cb = image_size(info); |
| |
| if (cb > 16384) return 15; |
| if (cb > 8192) return 14; |
| if (cb > 4096) return 13; |
| if (cb > 2048) return 12; |
| if (cb > 1024) return 11; |
| if (cb > 512) return 10; |
| if (cb > 256) return 9; |
| return 8; |
| } |
| |
| static void |
| error_handler(png_structp png_ptr, png_const_charp message) |
| { |
| if (strcmp(message, "IDAT: invalid distance too far back") == 0) |
| idat_error = 1; |
| |
| else if (errors || verbose) |
| fprintf(stderr, "%s: %s\n", name, message); |
| |
| png_longjmp(png_ptr, 1); |
| } |
| |
| static void |
| warning_handler(png_structp png_ptr, png_const_charp message) |
| { |
| if (warnings || verbose) |
| fprintf(stderr, "%s: %s\n", name, message); |
| |
| (void)png_ptr; |
| } |
| |
| static int |
| read_png(FILE *fp) |
| { |
| png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,0, |
| error_handler, warning_handler); |
| png_infop info_ptr = NULL; |
| png_bytep row = NULL, display = NULL; |
| |
| if (png_ptr == NULL) |
| return 0; |
| |
| if (setjmp(png_jmpbuf(png_ptr))) |
| { |
| png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| if (row != NULL) free(row); |
| if (display != NULL) free(display); |
| return 0; |
| } |
| |
| # ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW, set_option != 0); |
| # endif |
| |
| png_init_io(png_ptr, fp); |
| |
| info_ptr = png_create_info_struct(png_ptr); |
| if (info_ptr == NULL) |
| png_error(png_ptr, "OOM allocating info structure"); |
| |
| png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, NULL, 0); |
| |
| png_read_info(png_ptr, info_ptr); |
| |
| /* Limit the decompression buffer size to 1 - this ensures that overlong |
| * length codes are always detected. |
| */ |
| png_set_compression_buffer_size(png_ptr, 1); |
| |
| { |
| png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr); |
| |
| row = png_voidcast(png_byte*, malloc(rowbytes)); |
| display = png_voidcast(png_byte*, malloc(rowbytes)); |
| |
| if (row == NULL || display == NULL) |
| png_error(png_ptr, "OOM allocating row buffers"); |
| |
| { |
| png_uint_32 height = png_get_image_height(png_ptr, info_ptr); |
| int passes = png_set_interlace_handling(png_ptr); |
| int pass; |
| |
| png_start_read_image(png_ptr); |
| |
| for (pass = 0; pass < passes; ++pass) |
| { |
| png_uint_32 y = height; |
| |
| /* NOTE: this trashes the row each time; interlace handling won't |
| * work, but this avoids memory thrashing for speed testing. |
| */ |
| while (y-- > 0) |
| png_read_row(png_ptr, row, display); |
| } |
| } |
| } |
| |
| /* Make sure to read to the end of the file: */ |
| png_read_end(png_ptr, info_ptr); |
| png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| free(row); |
| free(display); |
| return 1; |
| } |
| |
| /* Chunk tags (copied from pngpriv.h) */ |
| #define PNG_32b(b,s) ((png_uint_32)(b) << (s)) |
| #define PNG_CHUNK(b1,b2,b3,b4) \ |
| (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0)) |
| |
| #define png_IHDR PNG_CHUNK( 73, 72, 68, 82) |
| #define png_IDAT PNG_CHUNK( 73, 68, 65, 84) |
| #define png_IEND PNG_CHUNK( 73, 69, 78, 68) |
| #define png_PLTE PNG_CHUNK( 80, 76, 84, 69) |
| #define png_bKGD PNG_CHUNK( 98, 75, 71, 68) |
| #define png_cHRM PNG_CHUNK( 99, 72, 82, 77) |
| #define png_gAMA PNG_CHUNK(103, 65, 77, 65) |
| #define png_hIST PNG_CHUNK(104, 73, 83, 84) |
| #define png_iCCP PNG_CHUNK(105, 67, 67, 80) |
| #define png_iTXt PNG_CHUNK(105, 84, 88, 116) |
| #define png_oFFs PNG_CHUNK(111, 70, 70, 115) |
| #define png_pCAL PNG_CHUNK(112, 67, 65, 76) |
| #define png_sCAL PNG_CHUNK(115, 67, 65, 76) |
| #define png_pHYs PNG_CHUNK(112, 72, 89, 115) |
| #define png_sBIT PNG_CHUNK(115, 66, 73, 84) |
| #define png_sPLT PNG_CHUNK(115, 80, 76, 84) |
| #define png_sRGB PNG_CHUNK(115, 82, 71, 66) |
| #define png_sTER PNG_CHUNK(115, 84, 69, 82) |
| #define png_tEXt PNG_CHUNK(116, 69, 88, 116) |
| #define png_tIME PNG_CHUNK(116, 73, 77, 69) |
| #define png_tRNS PNG_CHUNK(116, 82, 78, 83) |
| #define png_zTXt PNG_CHUNK(122, 84, 88, 116) |
| |
| static void |
| rx(FILE *fp, png_bytep buf, off_t cb) |
| { |
| if (fread(buf,cb,1,fp) != 1) { |
| fprintf(stderr, "%s: failed to read %lu bytes\n", name, |
| (unsigned long)cb); |
| exit(2); |
| } |
| } |
| |
| static png_uint_32 |
| r32(FILE *fp) |
| { |
| png_byte buf[4]; |
| rx(fp, buf, 4); |
| return ((((((png_uint_32)buf[0] << 8)+buf[1]) << 8)+buf[2]) << 8) + buf[3]; |
| } |
| |
| static void |
| wx(FILE *fp, png_const_bytep buf, off_t cb) |
| { |
| if (fwrite(buf,cb,1,fp) != 1) { |
| fprintf(stderr, "%s: failed to write %lu bytes\n", name, |
| (unsigned long)cb); |
| exit(3); |
| } |
| } |
| |
| static void |
| w32(FILE *fp, png_uint_32 val) |
| { |
| png_byte buf[4]; |
| buf[0] = (png_byte)(val >> 24); |
| buf[1] = (png_byte)(val >> 16); |
| buf[2] = (png_byte)(val >> 8); |
| buf[3] = (png_byte)(val); |
| wx(fp, buf, 4); |
| } |
| |
| static void |
| wcrc(FILE *fp, uLong crc) |
| { |
| /* Safe cast because a CRC is 32 bits */ |
| w32(fp, (png_uint_32)crc); |
| } |
| |
| static void |
| copy(FILE *fp, FILE *fpIn, off_t cb) |
| { |
| png_byte buffer[1024]; |
| |
| while (cb >= 1024) |
| { |
| rx(fpIn, buffer, 1024); |
| wx(fp, buffer, 1024); |
| cb -= 1024; |
| } |
| |
| if (cb > 0) |
| { |
| rx(fpIn, buffer, cb); |
| wx(fp, buffer, cb); |
| } |
| } |
| |
| static void |
| skip_bytes(FILE *fpIn, png_uint_32 cb) |
| { |
| png_byte buffer[1024]; |
| |
| while (cb >= 1024) |
| { |
| rx(fpIn, buffer, 1024); |
| cb -= 1024; |
| } |
| |
| if (cb > 0) |
| rx(fpIn, buffer, cb); |
| } |
| |
| static void |
| safe_getpos(FILE *fp, fpos_t *pos) |
| { |
| if (fgetpos(fp, pos)) |
| { |
| perror("tmpfile"); |
| fprintf(stderr, "%s: tmpfile fgetpos failed\n", name); |
| exit(3); |
| } |
| } |
| |
| static void |
| safe_setpos(FILE *fp, fpos_t *pos) |
| { |
| if (fflush(fp)) |
| { |
| perror("tmpfile"); |
| fprintf(stderr, "%s: tmpfile fflush failed\n", name); |
| exit(3); |
| } |
| |
| if (fsetpos(fp, pos)) |
| { |
| perror("tmpfile"); |
| fprintf(stderr, "%s: tmpfile fsetpos failed\n", name); |
| exit(3); |
| } |
| } |
| |
| static void |
| idat_update(FILE *fp, IDAT_info *info) |
| { |
| uLong crc; |
| |
| safe_setpos(fp, &info->header_pos); |
| wx(fp, info->header, 2); |
| |
| crc = crc32(crc_IDAT_head, info->header, 2); |
| crc = crc32_combine(crc, info->crc_tail, info->len_tail); |
| |
| safe_setpos(fp, &info->crc_pos); |
| wcrc(fp, crc); |
| } |
| |
| static void |
| set_bits(const char *file, FILE *fp, IDAT_info *info, int bits) |
| { |
| int byte1 = (info->header[0] & 0xf) + ((bits-8) << 4); |
| int byte2 = info->header[1] & 0xe0; |
| |
| /* The checksum calculation: */ |
| byte2 += 0x1f - ((byte1 << 8) + byte2) % 0x1f; |
| |
| info->header[0] = (png_byte)byte1; |
| info->header[1] = (png_byte)byte2; |
| |
| if (verbose) |
| fprintf(stderr, "%s: trying windowBits %d (Z_CMF = 0x%x)\n", file, bits, |
| byte1); |
| |
| idat_update(fp, info); |
| } |
| |
| static void |
| ptagchar(png_uint_32 ch) |
| { |
| ch &= 0xff; |
| if (isprint(ch)) |
| putc(ch, stderr); |
| |
| else |
| fprintf(stderr, "[%02x]", ch); |
| } |
| |
| static void |
| ptag(png_uint_32 tag) |
| { |
| if (tag != 0) |
| { |
| ptag(tag >> 8); |
| ptagchar(tag); |
| } |
| } |
| |
| static int |
| fix_one(FILE *fp, FILE *fpIn, IDAT_info *info, png_uint_32 max_IDAT, int strip) |
| { |
| int state = 0; |
| /* 0: at beginning, before first IDAT |
| * 1: read first CMF header byte |
| * 2: read second byte, in first IDAT |
| * 3: after first IDAT |
| * +4: saw deflate stream end. |
| */ |
| int truncated_idat = 0; /* Count of spurious IDAT bytes */ |
| uLong crc_idat = 0; /* Running CRC of current IDAT */ |
| png_uint_32 len_IDAT = 0; /* Length of current IDAT */ |
| fpos_t pos_IDAT_length; /* fpos_t of length field in current IDAT */ |
| |
| /* The signature: */ |
| { |
| png_byte buf[8]; |
| rx(fpIn, buf, 8); |
| wx(fp, buf, 8); |
| } |
| |
| info->file_size = 45; /* signature + IHDR + IEND */ |
| |
| for (;;) /* Chunk for loop */ |
| { |
| png_uint_32 len = r32(fpIn); |
| png_uint_32 tag = r32(fpIn); |
| |
| if (tag == png_IHDR) |
| { |
| /* Need width, height, color type, bit depth and interlace for the |
| * file. |
| */ |
| info->width = r32(fpIn); |
| info->height = r32(fpIn); |
| rx(fpIn, &info->bit_depth, 1); |
| rx(fpIn, &info->color_type, 1); |
| rx(fpIn, &info->compression_method, 1); |
| rx(fpIn, &info->filter_method, 1); |
| rx(fpIn, &info->interlace_method, 1); |
| |
| /* And write the information. */ |
| w32(fp, len); |
| w32(fp, tag); |
| w32(fp, info->width); |
| w32(fp, info->height); |
| wx(fp, &info->bit_depth, 1); |
| wx(fp, &info->color_type, 1); |
| wx(fp, &info->compression_method, 1); |
| wx(fp, &info->filter_method, 1); |
| wx(fp, &info->interlace_method, 1); |
| |
| /* Copy the CRC */ |
| copy(fp, fpIn, 4); |
| } |
| |
| else if (tag == png_IEND) |
| { |
| /* Ok, write an IEND chunk and finish. */ |
| w32(fp, 0); |
| w32(fp, png_IEND); |
| wcrc(fp, crc_IEND); |
| break; |
| } |
| |
| else if (tag == png_IDAT && len > 0) |
| { |
| /* Write the chunk header now if it hasn't been written yet */ |
| if (len_IDAT == 0) |
| { |
| /* The length is set at the end: */ |
| safe_getpos(fp, &pos_IDAT_length); |
| w32(fp, max_IDAT); /* length, not yet written */ |
| w32(fp, png_IDAT); |
| |
| if (state == 0) /* Start of first IDAT */ |
| { |
| safe_getpos(fp, &info->header_pos); |
| /* This will become info->crc_tail: */ |
| crc_idat = crc32(0L, Z_NULL, 0); |
| } |
| |
| else |
| crc_idat = crc_IDAT_head; |
| } |
| |
| /* Do the zlib 2-byte header, it gets written out but not added |
| * to the CRC (yet): |
| */ |
| while (len > 0 && state < 2) |
| { |
| rx(fpIn, info->header + state, 1); |
| wx(fp, info->header + state, 1); |
| ++len_IDAT; |
| --len; |
| |
| if (state++ == 1) |
| { |
| /* The zlib stream is used to validate the compressed IDAT |
| * data in the most relaxed way possible. |
| */ |
| png_byte bdummy; |
| int ret; |
| |
| z_idat.next_in = info->header; |
| z_idat.avail_in = 2; |
| z_idat.next_out = &bdummy; /* Else Z_STREAM_ERROR! */ |
| z_idat.avail_out = 0; |
| |
| ret = inflate(&z_idat, Z_NO_FLUSH); |
| if (ret != Z_OK || z_idat.avail_in != 0) |
| { |
| fprintf(stderr, |
| "%s: unexpected/invalid inflate result %d \"%s\"\n", |
| name, ret, z_idat.msg); |
| return 1; |
| } |
| } |
| } /* while in zlib header */ |
| |
| /* Process further bytes in the IDAT chunk */ |
| while (len > 0 && state < 4) |
| { |
| png_byte b; |
| |
| rx(fpIn, &b, 1); |
| --len; |
| |
| /* Do this 1 byte at a time to guarantee |
| * detecting errors (in particular zlib can skip the |
| * 'too-far-back' error if the output buffer is bigger than |
| * the window size.) |
| */ |
| z_idat.next_in = &b; |
| z_idat.avail_in = 1; |
| |
| do |
| { |
| int ret; |
| png_byte bout; |
| |
| z_idat.next_out = &bout; |
| z_idat.avail_out = 1; |
| |
| ret = inflate(&z_idat, Z_SYNC_FLUSH); |
| |
| if (z_idat.avail_out == 0) |
| ++info->image_size; |
| |
| switch (ret) |
| { |
| case Z_OK: |
| /* Just keep going */ |
| break; |
| |
| case Z_BUF_ERROR: |
| if (z_idat.avail_in > 0) |
| { |
| fprintf(stderr, |
| "%s: unexpected buffer error \"%s\"\n", |
| name, z_idat.msg); |
| return 1; |
| } |
| goto end_loop; |
| |
| case Z_STREAM_END: |
| /* End of stream */ |
| state |= 4; |
| goto end_loop; |
| |
| default: |
| fprintf(stderr, "%s: bad zlib stream %d, \"%s\"\n", |
| name, ret, z_idat.msg); |
| return 1; |
| } |
| } while (z_idat.avail_in > 0 || z_idat.avail_out == 0); |
| |
| /* The byte need not be consumed, if, for example, there is a |
| * spurious byte after the end of the zlib data. |
| */ |
| end_loop: |
| if (z_idat.avail_in == 0) |
| { |
| /* Write it and update the length information and running |
| * CRC. |
| */ |
| wx(fp, &b, 1); |
| crc_idat = crc32(crc_idat, &b, 1); |
| ++len_IDAT; |
| } |
| |
| else |
| ++truncated_idat; |
| |
| if (len_IDAT >= max_IDAT || state >= 4) |
| { |
| /* Either the IDAT chunk is full or we've seen the end of |
| * the deflate stream, or both. Flush the chunk and handle |
| * the details of the first chunk. |
| */ |
| fpos_t save; |
| |
| if ((state & 3) < 3) /* First IDAT */ |
| { |
| safe_getpos(fp, &info->crc_pos); |
| info->crc_tail = crc_idat; |
| info->len_tail = len_IDAT-2; |
| } |
| |
| /* This is not the correct value for the first IDAT! */ |
| wcrc(fp, crc_idat); |
| state |= 3; |
| |
| /* Update the length if it is not max_IDAT: */ |
| if (len_IDAT != max_IDAT) |
| { |
| safe_getpos(fp, &save); |
| safe_setpos(fp, &pos_IDAT_length); |
| w32(fp, len_IDAT); |
| safe_setpos(fp, &save); |
| } |
| |
| /* Add this IDAT to the file size: */ |
| info->file_size += 12 + len_IDAT; |
| } |
| } /* while len > 0 && state < 4 */ |
| |
| /* The above loop only exits on 0 bytes left or end of stream. If |
| * the stream ended with bytes left, discard them: |
| */ |
| if (len > 0) |
| { |
| truncated_idat += len; |
| /* Skip those bytes and the CRC */ |
| skip_bytes(fpIn, len+4); |
| } |
| |
| else |
| skip_bytes(fpIn, 4); /* The CRC */ |
| } /* IDAT and len > 0 */ |
| |
| else |
| { |
| int skip = 0; |
| |
| if (tag == png_IDAT) |
| skip = 1; |
| |
| else if (state == 0) |
| { |
| /* Chunk before IDAT */ |
| if (!skip) switch (strip) |
| { |
| case 0: /* Don't strip */ |
| break; |
| |
| case 1: /* Keep gAMA, sRGB */ |
| if (tag == png_gAMA || tag == png_sRGB) |
| break; |
| /* Fall through */ |
| |
| default: /* Keep only IHDR, PLTE, tRNS */ |
| if (tag == png_IHDR || tag == png_PLTE || tag == png_tRNS) |
| break; |
| |
| skip = 1; |
| break; |
| } |
| } |
| |
| else if (state >= 4) |
| { |
| /* Keep nothing after IDAT if stripping: */ |
| skip = strip; |
| } |
| |
| else |
| { |
| /* This is either an unterminated deflate stream or a spurious |
| * non-IDAT chunk in the list of IDAT chunks. Both are fatal |
| * errors. |
| */ |
| fprintf(stderr, "%s: tag '", name); |
| ptag(tag); |
| fprintf(stderr, "' after unterminated IDAT\n"); |
| break; |
| } |
| |
| /* Skip or send? */ |
| if (skip) |
| { |
| if (tag != png_IDAT && (tag & 0x20000000) == 0) |
| { |
| fprintf(stderr, "%s: unknown critical chunk '", name); |
| ptag(tag); |
| fprintf(stderr, "'\n"); |
| return 1; |
| } |
| |
| /* Skip this tag */ |
| if (fseek(fpIn, len+4, SEEK_CUR)) |
| { |
| perror(name); |
| fprintf(stderr, "%s: seek failed\n", name); |
| return 1; |
| } |
| } |
| |
| else /* Keep this tag */ |
| { |
| w32(fp, len); |
| w32(fp, tag); |
| copy(fp, fpIn, len+4); |
| info->file_size += 12+len; |
| } |
| } /* Not IDAT or len == 0 */ |
| } /* Chunk for loop */ |
| |
| /* Break out of the loop on error or end */ |
| if (state >= 4) |
| { |
| if (truncated_idat) |
| fprintf(stderr, "%s: removed %d bytes from end of IDAT\n", name, |
| truncated_idat); |
| |
| return 0; /* success */ |
| } |
| |
| /* This is somewhat generic but it works: */ |
| fprintf(stderr, "%s: unterminated/truncated PNG (%d)\n", name, state); |
| |
| return 1; |
| } |
| |
| static FILE *fpIn; |
| |
| static int |
| fix_file(FILE *fp, const char *file, png_uint_32 max_IDAT, int inplace, |
| int strip, int optimize, const char *output) |
| { |
| IDAT_info info; |
| int imageBits, oldBits, bestBits, lowBits, newBits, ok_read; |
| |
| memset(&info, 0, sizeof info); |
| |
| name = file; |
| idat_error = 0; |
| |
| /* fpIn is closed by the caller if necessary */ |
| fpIn = fopen(file, "rb"); |
| if (fpIn == NULL) |
| { |
| perror(file); |
| fprintf(stderr, "%s: open failed\n", file); |
| return 1; |
| } |
| |
| /* With no arguments just check this file */ |
| if (optimize == 0 && strip == 0 && inplace == 0 && output == NULL) |
| return !read_png(fpIn); |
| |
| /* Otherwise, maybe, fix it */ |
| if (fix_one(fp, fpIn, &info, max_IDAT, strip)) |
| return 1; |
| |
| /* oldBits may be invalid, imageBits is always OK, newBits always records the |
| * actual window bits of the temporary file (fp). |
| */ |
| bestBits = imageBits = image_windowBits(&info); |
| newBits = oldBits = 8+(info.header[0] >> 4); |
| ok_read = 0; /* records a successful read */ |
| |
| /* Find the optimal (lowest) newBits */ |
| if (optimize) |
| for (lowBits=8; lowBits < bestBits;) |
| { |
| /* This will always set 'newBits' to a value lower than 'bestBits' because |
| * 'lowBits' is less than 'bestBits': |
| */ |
| newBits = (bestBits + lowBits) >> 1; |
| |
| set_bits(file, fp, &info, newBits); |
| |
| rewind(fp); |
| idat_error = 0; |
| |
| if (!read_png(fp)) |
| { |
| /* If idat_error is *not* set this is some other problem */ |
| if (!idat_error) |
| return 1; |
| |
| /* This is the hypothetical case where the IDAT has too much data *and* |
| * the window size is wrong. In fact this should never happen because |
| * of the way libpng handles a deflate stream that produces extra data. |
| */ |
| if (newBits >= imageBits) |
| { |
| fprintf(stderr, "%s: imageBits(%d) too low (%d)\n", file, imageBits, |
| newBits); |
| return 1; |
| } |
| |
| if (lowBits <= newBits) |
| lowBits = newBits+1; |
| } |
| |
| else |
| { |
| bestBits = newBits; |
| ok_read = 1; |
| } |
| } |
| |
| else if (bestBits > oldBits) |
| { |
| /* See if the original value is ok */ |
| rewind(fp); |
| idat_error = 0; |
| |
| if (read_png(fp)) |
| { |
| ok_read = 1; |
| bestBits = oldBits; |
| } |
| |
| else if (!idat_error) |
| return 1; |
| |
| /* Otherwise there is an IDAT error and no optimization is being done, so |
| * just use imageBits (which is already set in bestBits). |
| */ |
| } |
| |
| if (newBits != bestBits) |
| { |
| /* Update the header to the required value */ |
| newBits = bestBits; |
| |
| set_bits(file, fp, &info, newBits); |
| } |
| |
| if (!ok_read) |
| { |
| /* bestBits has not been checked */ |
| idat_error = 0; |
| rewind(fp); |
| ok_read = read_png(fp); |
| |
| if (idat_error) |
| { |
| /* This should never happen */ |
| fprintf(stderr, "%s: imageBits(%d) too low [%d]\n", file, imageBits, |
| newBits); |
| return 1; |
| } |
| |
| /* This means that the PNG has some other error */ |
| if (!ok_read) |
| return 1; |
| } |
| |
| /* Have a valid newBits */ |
| if (optimize) |
| printf("%2d %2d %2d %s %s %d %s\n", newBits, oldBits, imageBits, |
| newBits < imageBits ? "<" : "=", |
| newBits < oldBits ? "reduce " : |
| (newBits > oldBits ? "INCREASE" : "ok "), |
| newBits - oldBits, name); |
| |
| # ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| /* Because setting libpng to use the maximum window bits breaks the |
| * read_png test above. |
| */ |
| if (set_option) |
| return 0; |
| # endif |
| |
| if (output != NULL || (inplace && (bestBits != oldBits || strip))) |
| { |
| FILE *fpOut; |
| |
| if (output != NULL) |
| fpOut = fopen(output, "wb"); |
| |
| else |
| { |
| fpOut = freopen(file, "wb", fpIn); |
| fpIn = NULL; |
| } |
| |
| if (fpOut == NULL) |
| { |
| perror(output); |
| fprintf(stderr, "%s: %s: open failed\n", file, output); |
| exit(3); |
| } |
| |
| rewind(fp); |
| copy(fpOut, fp, info.file_size); |
| |
| if (fflush(fpOut) || ferror(fpOut) || fclose(fpOut)) |
| { |
| perror(output != NULL ? output : file); |
| fprintf(stderr, "%s: %s: close failed\n", file, output); |
| if (output != NULL) |
| remove(output); |
| exit(3); |
| } |
| } |
| |
| return 0; |
| } |
| |
| static void |
| usage(const char *prog, int rc) |
| { |
| /* ANSI C-90 limits strings to 509 characters, so use a string array: */ |
| size_t i; |
| static const char *usage_string[] = { |
| " Tests, optimizes and optionally fixes the zlib header in PNG files.\n", |
| " Optionally, when fixing, strips ancilliary chunks from the file.\n", |
| "\n", |
| "OPTIONS\n", |
| " OPERATION\n", |
| " By default files are just checked for readability.\n", |
| " --optimize (-o):\n", |
| " Find the smallest deflate window size for the file, also outputs\n", |
| " a summary of the result for each file.\n", |
| " --strip (-s):\n", |
| " Remove chunks except for IHDR, PLTE, IEND, tRNS, gAMA, sRGB. If\n", |
| " given twice remove gAMA and sRGB as well.\n", |
| " --max=<number>:\n", |
| " Use IDAT chunks sized <number>. If not given the the IDAT\n", |
| " chunks will be the maximum size permitted; 2^31-1 bytes.\n", |
| " MESSAGES\n", |
| " By default the program is silent.\n", |
| " --errors (-e):\n", |
| " Output errors from libpng (except too-far-back).\n", |
| " --warnings (-w):\n", |
| " Output warnings from libpng.\n", |
| " --verbose (-v):\n", |
| " Describe program progress (refer to the source).\n", |
| " OUTPUT\n", |
| " By default nothing is written.\n", |
| " --out=<file>:\n", |
| " Write the optimized/corrected version of the next PNG to\n", |
| " <file>. This overrides the following two options\n", |
| " --suffix=<suffix>:\n", |
| " Set --out=<name><suffix> for all following files, unless\n", |
| " overridden on a per-file basis by explicit --out. If no\n", |
| " --suffix= value is given behaves as --inplace.\n", |
| " --inplace (-i):\n", |
| " Modify the file in place. THIS IS DANGEROUS - please keep a\n", |
| " backup of the file because a program interrupt or bug will\n", |
| " result in a corrupted file.\n", |
| #ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| " INTERNAL OPTIONS\n", |
| " --test:\n", |
| " Test the PNG_MAXIMUM_INFLATE_WINDOW option. Setting this\n", |
| " disables output as this would produce a broken file.\n", |
| #endif |
| "\n", |
| "EXIT CODES\n", |
| " 0: Success, all files pass the test, any output written ok.\n", |
| " 1: At least one file had a read error, all files checked.\n", |
| " 2: A file had an unrecoverable error (integer overflow, bad format),\n", |
| " the program exited immediately, without processing further files.\n", |
| " 3: An IO or out of memory error, or a file could not be opened.h\n", |
| "\n", |
| "DESCRIPTION\n", |
| " " PROGRAM_NAME " checks each PNG file on the command line\n", |
| " for errors. By default it is silent and just returns an exit code\n", |
| " (as above). Options allow the zlib error:\n", |
| "\n", |
| " \"invalid distance too far back\"\n", |
| "\n", |
| " to be fixed during the read and therefore test the file for other\n", |
| " errors that may prevent reading.\n", |
| "\n", |
| " Setting one of the \"OUTPUT\" options causes the possibly modified\n", |
| " file to be written to a new file or, with --inplace, to the existing\n", |
| " file.\n", |
| "\n", |
| " IMPORTANT: --inplace will overwrite the original file, if you use it\n", |
| " be sure to keep a backup of the original file, this program can fail\n", |
| " during the write and has been known to have serious bugs! A failure\n", |
| " during write will certainly damage the original file.\n", |
| "\n", |
| " Notice that some PNG files with the zlib header problem can still be\n", |
| " read by libpng under some circumstances. This program will still\n", |
| " detect and, if requested, correct the error.\n", |
| "\n", |
| " The output produced with --optimize is as follows:\n", |
| "\n", |
| " opt-bits curr-bits image-bits opt-flag opt-type change file\n", |
| "\n", |
| " opt-bits: The minimum window bits (8-15) that works, if the file\n", |
| " is written this is the value that will be stored.\n", |
| " curr-bits: The value currently stored in the file.\n", |
| " image-bits: The window bits value corresponding to the size of the\n", |
| " uncompressed PNG image data. When --optimize is not\n", |
| " given but --strip is, this value will be used if lower\n", |
| " than the current value.\n", |
| " opt-flag: < if the optimized bit value is less than that implied by\n", |
| " the PNG image size (opt-bits < image-bits)\n", |
| " = if optimization is not possible (opt-bits = image-bits)\n", |
| " opt-type: reduce if opts-bits < curr-bits\n", |
| " ok if opt-bits = curr-bits (no change required)\n", |
| " INCREASE if opt-bits > curr-bits (the file has the bug)\n", |
| " change: opt-bits - curr-bits, so negative if optimization is\n", |
| " possible, 0 if no change is required, positive if the\n", |
| " bug is present.\n", |
| " file: The file name.\n", |
| }; |
| |
| fprintf(stderr, "Usage: %s {[options] png-file}\n", prog); |
| |
| for (i=0; i < (sizeof usage_string)/(sizeof usage_string[0]); ++i) |
| fputs(usage_string[i], stderr); |
| |
| exit(rc); |
| } |
| |
| int |
| main(int argc, const char **argv) |
| { |
| int err, strip = 0, optimize = 0, inplace = 0, done = 0; |
| png_uint_32 max_IDAT = 0x7fffffff; |
| FILE *fp; |
| const char *outfile = NULL; |
| const char *suffix = NULL; |
| const char *prog = *argv; |
| static const png_byte idat_bytes[4] = { 73, 68, 65, 84 }; |
| static const png_byte iend_bytes[4] = { 73, 69, 78, 68 }; |
| |
| /* Initialize this first, could be stored as a constant: */ |
| crc_IEND = crc_IDAT_head = crc32(0L, Z_NULL, 0); |
| crc_IDAT_head = crc32(crc_IDAT_head, idat_bytes, 4); |
| crc_IEND = crc32(crc_IEND, iend_bytes, 4); |
| |
| z_idat.next_in = Z_NULL; |
| z_idat.avail_in = 0; |
| z_idat.zalloc = Z_NULL; |
| z_idat.zfree = Z_NULL; |
| z_idat.opaque = Z_NULL; |
| |
| err = inflateInit(&z_idat); |
| if (err != Z_OK) |
| { |
| fprintf(stderr, "inflateInit failed %d \"%s\"\n", err, z_idat.msg); |
| inflateEnd(&z_idat); |
| return 3; |
| } |
| |
| fp = tmpfile(); |
| if (fp == NULL) |
| { |
| perror("tmpfile"); |
| fprintf(stderr, "could not open a temporary file\n"); |
| return 3; |
| } |
| |
| err = 0; |
| while (--argc > 0) |
| { |
| ++argv; |
| |
| if (strcmp(*argv, "--inplace") == 0 || strcmp(*argv, "-i") == 0) |
| ++inplace; |
| |
| else if (strncmp(*argv, "--max=", 6) == 0) |
| max_IDAT = (png_uint_32)atol(6+*argv); |
| |
| else if (strcmp(*argv, "--optimize") == 0 || strcmp(*argv, "-o") == 0) |
| ++optimize; |
| |
| else if (strncmp(*argv, "--out=", 6) == 0) |
| outfile = 6+*argv; |
| |
| else if (strncmp(*argv, "--suffix=", 9) == 0) |
| suffix = 9+*argv; |
| |
| else if (strcmp(*argv, "--strip") == 0 || strcmp(*argv, "-s") == 0) |
| ++strip; |
| |
| else if (strcmp(*argv, "--errors") == 0 || strcmp(*argv, "-e") == 0) |
| ++errors; |
| |
| else if (strcmp(*argv, "--warnings") == 0 || strcmp(*argv, "-w") == 0) |
| ++warnings; |
| |
| else if (strcmp(*argv, "--verbose") == 0 || strcmp(*argv, "-v") == 0) |
| ++verbose; |
| |
| # ifdef PNG_MAXIMUM_INFLATE_WINDOW |
| else if (strcmp(*argv, "--test") == 0) |
| ++set_option; |
| # endif |
| |
| else if ((*argv)[0] == '-') |
| usage(prog, 3); |
| |
| else |
| { |
| int ret, overwrite; |
| |
| if (outfile != NULL) |
| overwrite = 0; |
| |
| else if (suffix != NULL) |
| { |
| if (*suffix == 0) |
| overwrite = 1; |
| |
| else |
| { |
| static char temp_name[FILENAME_MAX]; |
| size_t filelen = strlen(*argv); |
| size_t suffixlen = strlen(suffix); |
| |
| if (filelen + suffixlen >= FILENAME_MAX) |
| { |
| fprintf(stderr, "%s: output file name too long: %s%s\n", prog, |
| *argv, suffix); |
| exit(3); |
| } |
| |
| memcpy(temp_name, *argv, filelen); |
| memcpy(temp_name+filelen, suffix, suffixlen); |
| temp_name[filelen+suffixlen] = 0; |
| |
| outfile = temp_name; |
| overwrite = 0; |
| } |
| } |
| |
| else |
| overwrite = inplace; |
| |
| err += |
| fix_file(fp, *argv, max_IDAT, overwrite, strip, optimize, outfile); |
| |
| if (fpIn != NULL) |
| { |
| fclose(fpIn); |
| fpIn = NULL; |
| } |
| |
| z_idat.next_in = z_idat.next_out = Z_NULL; |
| z_idat.avail_in = z_idat.avail_out = 0; |
| ret = inflateReset(&z_idat); |
| if (ret != Z_OK) |
| { |
| fprintf(stderr, "inflateReset failed %d \"%s\"\n", ret, z_idat.msg); |
| inflateEnd(&z_idat); |
| return 3; |
| } |
| |
| rewind(fp); |
| outfile = NULL; |
| ++done; |
| } |
| } |
| |
| inflateEnd(&z_idat); |
| |
| if (!done) |
| usage(prog, 0); |
| |
| return err != 0; |
| } |
| |
| #else /* PNG_ZLIB_VERNUM < 0x1240 */ |
| int |
| main(void) |
| { |
| fprintf(stderr, |
| "png-fix-too-far-back needs libpng with a zlib >=1.2.4 (not 0x%x)\n", |
| PNG_ZLIB_VERNUM); |
| return 77; |
| } |
| #endif /* PNG_ZLIB_VERNUM */ |
| |
| #else /* No read support */ |
| |
| int |
| main(void) |
| { |
| fprintf(stderr, "png-fix-too-far-back does not work without read support\n"); |
| return 77; |
| } |
| #endif /* PNG_READ_SUPPORTED */ |
