/* pngunknown.c - test the read side unknown chunk handling * * Last changed in libpng 1.6.0 [(PENDING RELEASE)] * Copyright (c) 2013 Glenn Randers-Pehrson * Written by John Cunningham Bowler * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h * * NOTES: * This is a C program that is intended to be linked against libpng. It * allows the libpng unknown handling code to be tested by interpreting * arguments to save or discard combinations of chunks. The program is * currently just a minimal validation for the built-in libpng facilities. */ #include #include #include #include /* Define the following to use this test against your installed libpng, rather * than the one being built here: */ #ifdef PNG_FREESTANDING_TESTS # include #else # include "../../png.h" #endif #ifdef PNG_READ_SUPPORTED #if PNG_LIBPNG_VER < 10500 /* This deliberately lacks the PNG_CONST. */ typedef png_byte *png_const_bytep; /* This is copied from 1.5.1 png.h: */ #define PNG_INTERLACE_ADAM7_PASSES 7 #define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7) #define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7) #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3) #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3) #define PNG_PASS_ROWS(height, pass) (((height)+(((1<>PNG_PASS_ROW_SHIFT(pass)) #define PNG_PASS_COLS(width, pass) (((width)+(((1<>PNG_PASS_COL_SHIFT(pass)) #define PNG_ROW_FROM_PASS_ROW(yIn, pass) \ (((yIn)<>(((7-(off))-(pass))<<2)) & 0xFU) | \ ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U)) #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \ ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1) #define PNG_COL_IN_INTERLACE_PASS(x, pass) \ ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1) /* These are needed too for the default build: */ #define PNG_WRITE_16BIT_SUPPORTED #define PNG_READ_16BIT_SUPPORTED /* This comes from pnglibconf.h afer 1.5: */ #define PNG_FP_1 100000 #define PNG_GAMMA_THRESHOLD_FIXED\ ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1)) #endif #if PNG_LIBPNG_VER < 10600 /* 1.6.0 constifies many APIs. The following exists to allow pngvalid to be * compiled against earlier versions. */ # define png_const_structp png_structp #endif /* 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) #define png_vpAg PNG_CHUNK('v', 'p', 'A', 'g') /* Test on flag values as defined in the spec (section 5.4): */ #define PNG_CHUNK_ANCILLARY(c ) (1 & ((c) >> 29)) #define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c)) #define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21)) #define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13)) #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5)) /* Chunk information */ #define PNG_INFO_tEXt 0x10000000U #define PNG_INFO_iTXt 0x20000000U #define PNG_INFO_zTXt 0x40000000U #define PNG_INFO_sTER 0x01000000U #define PNG_INFO_vpAg 0x02000000U #define ABSENT 0 #define START 1 #define END 2 static struct { char name[5]; png_uint_32 flag; png_uint_32 tag; int unknown; /* Chunk not known to libpng */ int all; /* Chunk set by the '-1' option */ int position; /* position in pngtest.png */ int keep; /* unknown handling setting */ } chunk_info[] = { /* Critical chunks */ { "IDAT", PNG_INFO_IDAT, png_IDAT, 0, 0, START, 0 }, /* must be [0] */ { "PLTE", PNG_INFO_PLTE, png_PLTE, 0, 0, ABSENT, 0 }, /* Non-critical chunks that libpng handles */ { "bKGD", PNG_INFO_bKGD, png_bKGD, 0, 1, START, 0 }, { "cHRM", PNG_INFO_cHRM, png_cHRM, 0, 1, START, 0 }, { "gAMA", PNG_INFO_gAMA, png_gAMA, 0, 1, START, 0 }, { "hIST", PNG_INFO_hIST, png_hIST, 0, 1, ABSENT, 0 }, { "iCCP", PNG_INFO_iCCP, png_iCCP, 0, 1, ABSENT, 0 }, { "iTXt", PNG_INFO_iTXt, png_iTXt, 0, 1, ABSENT, 0 }, { "oFFs", PNG_INFO_oFFs, png_oFFs, 0, 1, START, 0 }, { "pCAL", PNG_INFO_pCAL, png_pCAL, 0, 1, START, 0 }, { "pHYs", PNG_INFO_pHYs, png_pHYs, 0, 1, START, 0 }, { "sBIT", PNG_INFO_sBIT, png_sBIT, 0, 1, START, 0 }, { "sCAL", PNG_INFO_sCAL, png_sCAL, 0, 1, START, 0 }, { "sPLT", PNG_INFO_sPLT, png_sPLT, 0, 1, ABSENT, 0 }, { "sRGB", PNG_INFO_sRGB, png_sRGB, 0, 1, START, 0 }, { "tEXt", PNG_INFO_tEXt, png_tEXt, 0, 1, START, 0 }, { "tIME", PNG_INFO_tIME, png_tIME, 0, 1, START, 0 }, { "tRNS", PNG_INFO_tRNS, png_tRNS, 0, 0, ABSENT, 0 }, { "zTXt", PNG_INFO_zTXt, png_zTXt, 0, 1, END, 0 }, /* No libpng handling */ { "sTER", PNG_INFO_sTER, png_sTER, 1, 1, START, 0 }, { "vpAg", PNG_INFO_vpAg, png_vpAg, 1, 0, START, 0 }, }; #define NINFO ((int)((sizeof chunk_info)/(sizeof chunk_info[0]))) static void clear_keep(void) { int i = NINFO; while (--i >= 0) chunk_info[i].keep = 0; } static int find(const char *name) { int i = NINFO; while (--i >= 0) { if (memcmp(chunk_info[i].name, name, 4) == 0) break; } return i; } static int findb(const png_byte *name) { int i = NINFO; while (--i >= 0) { if (memcmp(chunk_info[i].name, name, 4) == 0) break; } return i; } static int find_by_flag(png_uint_32 flag) { int i = NINFO; while (--i >= 0) if (chunk_info[i].flag == flag) return i; fprintf(stderr, "pngunknown: internal error\n"); exit(4); } static int ancillary(const char *name) { return PNG_CHUNK_ANCILLARY(PNG_CHUNK(name[0], name[1], name[2], name[3])); } static int ancillaryb(const png_byte *name) { return PNG_CHUNK_ANCILLARY(PNG_CHUNK(name[0], name[1], name[2], name[3])); } /* Type of an error_ptr */ typedef struct { jmp_buf error_return; png_structp png_ptr; png_infop info_ptr, end_ptr; int error_count; int warning_count; const char *program; const char *file; const char *test; } display; static const char init[] = "initialization"; static const char cmd[] = "command line"; static void init_display(display *d, const char *program) { memset(d, 0, sizeof *d); d->png_ptr = NULL; d->info_ptr = d->end_ptr = NULL; d->error_count = d->warning_count = 0; d->program = program; d->file = program; d->test = init; } static void clean_display(display *d) { png_destroy_read_struct(&d->png_ptr, &d->info_ptr, &d->end_ptr); /* This must not happen - it might cause an app crash */ if (d->png_ptr != NULL || d->info_ptr != NULL || d->end_ptr != NULL) { fprintf(stderr, "%s(%s): png_destroy_read_struct error\n", d->file, d->test); exit(1); } /* Invalidate the test */ d->test = init; } PNG_FUNCTION(void, display_exit, (display *d), static PNG_NORETURN) { ++(d->error_count); if (d->png_ptr != NULL) clean_display(d); /* During initialization and if this is a single command line argument set * exit now - there is only one test, otherwise longjmp to do the next test. */ if (d->test == init || d->test == cmd) exit(1); longjmp(d->error_return, 1); } static int display_rc(const display *d, int strict) { return d->error_count + (strict ? d->warning_count : 0); } /* libpng error and warning callbacks */ PNG_FUNCTION(void, error, (png_structp png_ptr, const char *message), static PNG_NORETURN) { display *d = (display*)png_get_error_ptr(png_ptr); fprintf(stderr, "%s(%s): libpng error: %s\n", d->file, d->test, message); display_exit(d); } static void warning(png_structp png_ptr, const char *message) { display *d = (display*)png_get_error_ptr(png_ptr); fprintf(stderr, "%s(%s): libpng warning: %s\n", d->file, d->test, message); ++(d->warning_count); } static png_uint_32 get_valid(display *d, png_infop info_ptr) { png_uint_32 flags = png_get_valid(d->png_ptr, info_ptr, (png_uint_32)~0); /* Map the text chunks back into the flags */ { png_textp text; png_uint_32 ntext = png_get_text(d->png_ptr, info_ptr, &text, NULL); while (ntext-- > 0) switch (text[ntext].compression) { case -1: flags |= PNG_INFO_tEXt; break; case 0: flags |= PNG_INFO_zTXt; break; case 1: case 2: flags |= PNG_INFO_iTXt; break; default: fprintf(stderr, "%s(%s): unknown text compression %d\n", d->file, d->test, text[ntext].compression); display_exit(d); } } return flags; } static png_uint_32 get_unknown(display *d, int def, png_infop info_ptr) { /* Create corresponding 'unknown' flags */ png_uint_32 flags = 0; { png_unknown_chunkp unknown; int num_unknown = png_get_unknown_chunks(d->png_ptr, info_ptr, &unknown); while (--num_unknown >= 0) { int chunk = findb(unknown[num_unknown].name); /* Chunks not known to pngunknown must be validated here; since they * must also be unknown to libpng the 'def' behavior should have been * used. */ if (chunk < 0) switch (def) { default: /* impossible */ case PNG_HANDLE_CHUNK_AS_DEFAULT: case PNG_HANDLE_CHUNK_NEVER: fprintf(stderr, "%s(%s): %s: %s: unknown chunk saved\n", d->file, d->test, def ? "discard" : "default", unknown[num_unknown].name); ++(d->error_count); break; case PNG_HANDLE_CHUNK_IF_SAFE: if (!ancillaryb(unknown[num_unknown].name)) { fprintf(stderr, "%s(%s): if-safe: %s: unknown critical chunk saved\n", d->file, d->test, unknown[num_unknown].name); ++(d->error_count); break; } /* FALL THROUGH (safe) */ case PNG_HANDLE_CHUNK_ALWAYS: break; } else flags |= chunk_info[chunk].flag; } } return flags; } static int check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/, display *d) { int i, def = PNG_HANDLE_CHUNK_AS_DEFAULT, npasses, ipass; png_uint_32 height; /* Some of these errors are permanently fatal and cause an exit here, others * are per-test and cause an error return. */ d->png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, d, error, warning); if (d->png_ptr == NULL) { fprintf(stderr, "%s(%s): could not allocate png struct\n", d->file, d->test); /* Terminate here, this error is not test specific. */ exit(1); } d->info_ptr = png_create_info_struct(d->png_ptr); d->end_ptr = png_create_info_struct(d->png_ptr); if (d->info_ptr == NULL || d->end_ptr == NULL) { fprintf(stderr, "%s(%s): could not allocate png info\n", d->file, d->test); clean_display(d); exit(1); } png_init_io(d->png_ptr, fp); /* Handle each argument in turn; multiple settings are possible for the same * chunk and multiple calls will occur (the last one should override all * preceding ones). */ for (i=0; ipng_ptr, option, name, 1); chunk_info[chunk].keep = option; # endif continue; } break; case 7: /* default */ if (memcmp(argv[i], "default", 7) == 0) { # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED png_set_keep_unknown_chunks(d->png_ptr, option, NULL, 0); # endif def = option; continue; } break; case 3: /* all */ if (memcmp(argv[i], "all", 3) == 0) { # ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED png_set_keep_unknown_chunks(d->png_ptr, option, NULL, -1); def = option; for (chunk = 0; chunk < NINFO; ++chunk) if (chunk_info[chunk].all) chunk_info[chunk].keep = option; # endif continue; } break; default: /* some misplaced = */ break; } } fprintf(stderr, "%s(%s): %s: unrecognized chunk argument\n", d->file, d->test, argv[i]); display_exit(d); } png_read_info(d->png_ptr, d->info_ptr); switch (png_get_interlace_type(d->png_ptr, d->info_ptr)) { case PNG_INTERLACE_NONE: npasses = 1; break; case PNG_INTERLACE_ADAM7: npasses = PNG_INTERLACE_ADAM7_PASSES; break; default: /* Hard error because it is not test specific */ fprintf(stderr, "%s(%s): invalid interlace type\n", d->file, d->test); clean_display(d); exit(1); } /* Skip the image data, if IDAT is not being handled then don't do this * because it will cause a CRC error. */ if (chunk_info[0/*IDAT*/].keep == PNG_HANDLE_CHUNK_AS_DEFAULT) { png_start_read_image(d->png_ptr); height = png_get_image_height(d->png_ptr, d->info_ptr); if (npasses > 1) { png_uint_32 width = png_get_image_width(d->png_ptr, d->info_ptr); for (ipass=0; ipass 0) { png_uint_32 y; for (y=0; ypng_ptr, NULL, NULL); } } } /* interlaced */ else /* not interlaced */ { png_uint_32 y; for (y=0; ypng_ptr, NULL, NULL); } } png_read_end(d->png_ptr, d->end_ptr); flags[0] = get_valid(d, d->info_ptr); flags[1] = get_unknown(d, def, d->info_ptr); /* Only png_read_png sets PNG_INFO_IDAT! */ flags[chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT] |= PNG_INFO_IDAT; flags[2] = get_valid(d, d->end_ptr); flags[3] = get_unknown(d, def, d->end_ptr); clean_display(d); return def; } static void check_error(display *d, png_uint_32 flags, const char *message) { while (flags) { png_uint_32 flag = flags & -(png_int_32)flags; int i = find_by_flag(flag); fprintf(stderr, "%s(%s): chunk %s: %s\n", d->file, d->test, chunk_info[i].name, message); ++(d->error_count); flags &= ~flag; } } static void check_handling(display *d, int def, png_uint_32 chunks, png_uint_32 known, png_uint_32 unknown, const char *position) { while (chunks) { png_uint_32 flag = chunks & -(png_int_32)chunks; int i = find_by_flag(flag); int keep = chunk_info[i].keep; const char *type; const char *errorx = NULL; if (chunk_info[i].unknown) { if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) { type = "UNKNOWN (default)"; keep = def; } else type = "UNKNOWN (specified)"; if (flag & known) errorx = "chunk processed"; else switch (keep) { case PNG_HANDLE_CHUNK_AS_DEFAULT: if (flag & unknown) errorx = "DEFAULT: unknown chunk saved"; break; case PNG_HANDLE_CHUNK_NEVER: if (flag & unknown) errorx = "DISCARD: unknown chunk saved"; break; case PNG_HANDLE_CHUNK_IF_SAFE: if (ancillary(chunk_info[i].name)) { if (!(flag & unknown)) errorx = "IF-SAFE: unknown ancillary chunk lost"; } else if (flag & unknown) errorx = "IF-SAFE: unknown critical chunk saved"; break; case PNG_HANDLE_CHUNK_ALWAYS: if (!(flag & unknown)) errorx = "SAVE: unknown chunk lost"; break; default: errorx = "internal error: bad keep"; break; } } /* unknown chunk */ else /* known chunk */ { type = "KNOWN"; if (flag & known) { /* chunk was processed, it won't have been saved because that is * caught below when checking for inconsistent processing. */ if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT) errorx = "!DEFAULT: known chunk processed"; } else /* not processed */ switch (keep) { case PNG_HANDLE_CHUNK_AS_DEFAULT: errorx = "DEFAULT: known chunk not processed"; break; case PNG_HANDLE_CHUNK_NEVER: if (flag & unknown) errorx = "DISCARD: known chunk saved"; break; case PNG_HANDLE_CHUNK_IF_SAFE: if (ancillary(chunk_info[i].name)) { if (!(flag & unknown)) errorx = "IF-SAFE: known ancillary chunk lost"; } else if (flag & unknown) errorx = "IF-SAFE: known critical chunk saved"; break; case PNG_HANDLE_CHUNK_ALWAYS: if (!(flag & unknown)) errorx = "SAVE: known chunk lost"; break; default: errorx = "internal error: bad keep (2)"; break; } } if (errorx != NULL) { ++(d->error_count); fprintf(stderr, "%s(%s): %s %s %s: %s\n", d->file, d->test, type, chunk_info[i].name, position, errorx); } chunks &= ~flag; } } static void perform_one_test(FILE *fp, int argc, const char **argv, png_uint_32 *default_flags, display *d) { int def; png_uint_32 flags[2][4]; rewind(fp); clear_keep(); memcpy(flags[0], default_flags, sizeof flags[0]); def = check(fp, argc, argv, flags[1], d); /* Chunks should either be known or unknown, never both and this should apply * whether the chunk is before or after the IDAT (actually, the app can * probably change this by swapping the handling after the image, but this * test does not do that.) */ check_error(d, (flags[0][0]|flags[0][2]) & (flags[0][1]|flags[0][3]), "chunk handled inconsistently in count tests"); check_error(d, (flags[1][0]|flags[1][2]) & (flags[1][1]|flags[1][3]), "chunk handled inconsistently in option tests"); /* Now find out what happened to each chunk before and after the IDAT and * determine if the behavior was correct. First some basic sanity checks, * any known chunk should be known in the original count, any unknown chunk * should be either known or unknown in the original. */ { png_uint_32 test; test = flags[1][0] & ~flags[0][0]; check_error(d, test, "new known chunk before IDAT"); test = flags[1][1] & ~(flags[0][0] | flags[0][1]); check_error(d, test, "new unknown chunk before IDAT"); test = flags[1][2] & ~flags[0][2]; check_error(d, test, "new known chunk after IDAT"); test = flags[1][3] & ~(flags[0][2] | flags[0][3]); check_error(d, test, "new unknown chunk after IDAT"); } /* Now each chunk in the original list should have been handled according to * the options set for that chunk, regardless of whether libpng knows about * it or not. */ check_handling(d, def, flags[0][0] | flags[0][1], flags[1][0], flags[1][1], "before IDAT"); check_handling(d, def, flags[0][2] | flags[0][3], flags[1][2], flags[1][3], "after IDAT"); } static void perform_one_test_safe(FILE *fp, int argc, const char **argv, png_uint_32 *default_flags, display *d, const char *test) { if (setjmp(d->error_return) == 0) { d->test = test; /* allow use of d->error_return */ perform_one_test(fp, argc, argv, default_flags, d); d->test = init; /* prevent use of d->error_return */ } } static const char *standard_tests[] = { "discard", "default=discard", 0, "save", "default=save", 0, "if-safe", "default=if-safe", 0, "vpAg", "vpAg=if-safe", 0, "sTER", "sTER=if-safe", 0, "IDAT", "default=discard", "IDAT=save", 0, "sAPI", "bKGD=save", "cHRM=save", "gAMA=save", "all=discard", "iCCP=save", "sBIT=save", "sRGB=save", 0, 0/*end*/ }; static PNG_NORETURN void usage(const char *program, const char *reason) { fprintf(stderr, "pngunknown: %s: usage:\n %s [--strict] " "--default|{(CHNK|default|all)=(default|discard|if-safe|save)} " "testfile.png\n", reason, program); exit(2); } int main(int argc, const char **argv) { FILE *fp; png_uint_32 default_flags[4/*valid,unknown{before,after}*/]; int strict = 0, default_tests = 0; const char *count_argv = "default=save"; const char *touch_file = NULL; display d; init_display(&d, argv[0]); while (++argv, --argc > 0) { if (strcmp(*argv, "--strict") == 0) strict = 1; else if (strcmp(*argv, "--default") == 0) default_tests = 1; else if (strcmp(*argv, "--touch") == 0) { if (argc > 1) touch_file = *++argv, --argc; else usage(d.program, "--touch: missing file name"); } else break; } /* A file name is required, but there should be no other arguments if * --default was specified. */ if (argc <= 0) usage(d.program, "missing test file"); /* GCC BUG: if (default_tests && argc != 1) triggers some weird GCC argc * optimization which causes warnings with -Wstrict-overflow! */ else if (default_tests) if (argc != 1) usage(d.program, "extra arguments"); # ifndef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED fprintf(stderr, "%s: warning: no 'save' support so arguments ignored\n", d.program); # endif /* The name of the test file is the last argument; remove it. */ d.file = argv[--argc]; fp = fopen(d.file, "rb"); if (fp == NULL) { perror(d.file); exit(2); } /* First find all the chunks, known and unknown, in the test file, a failure * here aborts the whole test. */ if (check(fp, 1, &count_argv, default_flags, &d) != PNG_HANDLE_CHUNK_ALWAYS) { fprintf(stderr, "%s: %s: internal error\n", d.program, d.file); exit(3); } /* Now find what the various supplied options cause to change: */ if (!default_tests) { d.test = cmd; /* acts as a flag to say exit, do not longjmp */ perform_one_test(fp, argc, argv, default_flags, &d); d.test = init; } else { const char **test = standard_tests; /* Set the exit_test pointer here so we can continue after a libpng error. * NOTE: this leaks memory because the png_struct data from the failing * test is never freed. */ while (*test) { const char *this_test = *test++; const char **next = test; int count = display_rc(&d, strict), new_count; const char *result; int arg_count = 0; while (*next) ++next, ++arg_count; perform_one_test_safe(fp, arg_count, test, default_flags, &d, this_test); new_count = display_rc(&d, strict); if (new_count == count) result = "PASS"; else result = "FAIL"; printf("%s: %s %s\n", result, d.program, this_test); test = next+1; } } fclose(fp); if (display_rc(&d, strict) == 0) { /* Success, touch the success file if appropriate */ if (touch_file != NULL) { FILE *fsuccess = fopen(touch_file, "wt"); if (fsuccess != NULL) { int err = 0; fprintf(fsuccess, "PNG unknown tests succeeded\n"); fflush(fsuccess); err = ferror(fsuccess); if (fclose(fsuccess) || err) { fprintf(stderr, "%s: write failed\n", touch_file); exit(1); } } else { fprintf(stderr, "%s: open failed\n", touch_file); exit(1); } } return 0; } return 1; } #else int main(void) { fprintf(stderr, " test ignored because libpng was not built with unknown chunk support\n"); return 0; } #endif