Home | History | Annotate | Download | only in libtests
      1 
      2 /* pngunknown.c - test the read side unknown chunk handling
      3  *
      4  * Last changed in libpng 1.6.10 [March 6, 2014]
      5  * Copyright (c) 2014 Glenn Randers-Pehrson
      6  * Written by John Cunningham Bowler
      7  *
      8  * This code is released under the libpng license.
      9  * For conditions of distribution and use, see the disclaimer
     10  * and license in png.h
     11  *
     12  * NOTES:
     13  *   This is a C program that is intended to be linked against libpng.  It
     14  *   allows the libpng unknown handling code to be tested by interpreting
     15  *   arguments to save or discard combinations of chunks.  The program is
     16  *   currently just a minimal validation for the built-in libpng facilities.
     17  */
     18 
     19 #include <stdlib.h>
     20 #include <string.h>
     21 #include <stdio.h>
     22 #include <setjmp.h>
     23 
     24 /* Define the following to use this test against your installed libpng, rather
     25  * than the one being built here:
     26  */
     27 #ifdef PNG_FREESTANDING_TESTS
     28 #  include <png.h>
     29 #else
     30 #  include "../../png.h"
     31 #endif
     32 
     33 /* Since this program tests the ability to change the unknown chunk handling
     34  * these must be defined:
     35  */
     36 #if defined(PNG_SET_UNKNOWN_CHUNKS_SUPPORTED) &&\
     37    defined(PNG_READ_SUPPORTED)
     38 
     39 /* One of these must be defined to allow us to find out what happened.  It is
     40  * still useful to set unknown chunk handling without either of these in order
     41  * to cause *known* chunks to be discarded.  This can be a significant
     42  * efficiency gain, but it can't really be tested here.
     43  */
     44 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED) ||\
     45    defined(PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED)
     46 
     47 #if PNG_LIBPNG_VER < 10500
     48 /* This deliberately lacks the PNG_CONST. */
     49 typedef png_byte *png_const_bytep;
     50 
     51 /* This is copied from 1.5.1 png.h: */
     52 #define PNG_INTERLACE_ADAM7_PASSES 7
     53 #define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
     54 #define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
     55 #define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
     56 #define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
     57 #define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
     58    -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
     59 #define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
     60    -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
     61 #define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
     62    (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
     63 #define PNG_COL_FROM_PASS_COL(xIn, pass) \
     64    (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
     65 #define PNG_PASS_MASK(pass,off) ( \
     66    ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
     67    ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
     68 #define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
     69    ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
     70 #define PNG_COL_IN_INTERLACE_PASS(x, pass) \
     71    ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
     72 
     73 /* These are needed too for the default build: */
     74 #define PNG_WRITE_16BIT_SUPPORTED
     75 #define PNG_READ_16BIT_SUPPORTED
     76 
     77 /* This comes from pnglibconf.h afer 1.5: */
     78 #define PNG_FP_1 100000
     79 #define PNG_GAMMA_THRESHOLD_FIXED\
     80    ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
     81 #endif
     82 
     83 #if PNG_LIBPNG_VER < 10600
     84    /* 1.6.0 constifies many APIs. The following exists to allow pngvalid to be
     85     * compiled against earlier versions.
     86     */
     87 #  define png_const_structp png_structp
     88 #endif
     89 
     90 #if PNG_LIBPNG_VER < 10700
     91    /* Copied from libpng 1.7.0 png.h */
     92 #define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2))
     93 
     94 #define PNG_U16(b1, b2) ((png_uint_16)PNG_u2(b1, b2))
     95 #define PNG_U32(b1, b2, b3, b4)\
     96    (((png_uint_32)PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4))
     97 
     98 /* Constants for known chunk types.
     99  */
    100 #define png_IDAT PNG_U32( 73,  68,  65,  84)
    101 #define png_IEND PNG_U32( 73,  69,  78,  68)
    102 #define png_IHDR PNG_U32( 73,  72,  68,  82)
    103 #define png_PLTE PNG_U32( 80,  76,  84,  69)
    104 #define png_bKGD PNG_U32( 98,  75,  71,  68)
    105 #define png_cHRM PNG_U32( 99,  72,  82,  77)
    106 #define png_fRAc PNG_U32(102,  82,  65,  99) /* registered, not defined */
    107 #define png_gAMA PNG_U32(103,  65,  77,  65)
    108 #define png_gIFg PNG_U32(103,  73,  70, 103)
    109 #define png_gIFt PNG_U32(103,  73,  70, 116) /* deprecated */
    110 #define png_gIFx PNG_U32(103,  73,  70, 120)
    111 #define png_hIST PNG_U32(104,  73,  83,  84)
    112 #define png_iCCP PNG_U32(105,  67,  67,  80)
    113 #define png_iTXt PNG_U32(105,  84,  88, 116)
    114 #define png_oFFs PNG_U32(111,  70,  70, 115)
    115 #define png_pCAL PNG_U32(112,  67,  65,  76)
    116 #define png_pHYs PNG_U32(112,  72,  89, 115)
    117 #define png_sBIT PNG_U32(115,  66,  73,  84)
    118 #define png_sCAL PNG_U32(115,  67,  65,  76)
    119 #define png_sPLT PNG_U32(115,  80,  76,  84)
    120 #define png_sRGB PNG_U32(115,  82,  71,  66)
    121 #define png_sTER PNG_U32(115,  84,  69,  82)
    122 #define png_tEXt PNG_U32(116,  69,  88, 116)
    123 #define png_tIME PNG_U32(116,  73,  77,  69)
    124 #define png_tRNS PNG_U32(116,  82,  78,  83)
    125 #define png_zTXt PNG_U32(122,  84,  88, 116)
    126 
    127 /* Test on flag values as defined in the spec (section 5.4): */
    128 #define PNG_CHUNK_ANCILLARY(c)    (1 & ((c) >> 29))
    129 #define PNG_CHUNK_CRITICAL(c)     (!PNG_CHUNK_ANCILLARY(c))
    130 #define PNG_CHUNK_PRIVATE(c)      (1 & ((c) >> 21))
    131 #define PNG_CHUNK_RESERVED(c)     (1 & ((c) >> 13))
    132 #define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >>  5))
    133 
    134 #endif /* PNG_LIBPNG_VER < 10700 */
    135 
    136 #ifdef __cplusplus
    137 #  define this not_the_cpp_this
    138 #  define new not_the_cpp_new
    139 #  define voidcast(type, value) static_cast<type>(value)
    140 #else
    141 #  define voidcast(type, value) (value)
    142 #endif /* __cplusplus */
    143 
    144 /* Unused formal parameter errors are removed using the following macro which is
    145  * expected to have no bad effects on performance.
    146  */
    147 #ifndef UNUSED
    148 #  if defined(__GNUC__) || defined(_MSC_VER)
    149 #     define UNUSED(param) (void)param;
    150 #  else
    151 #     define UNUSED(param)
    152 #  endif
    153 #endif
    154 
    155 /* Types of chunks not known to libpng */
    156 #define png_vpAg PNG_U32(118, 112, 65, 103)
    157 
    158 /* Chunk information */
    159 #define PNG_INFO_tEXt 0x10000000U
    160 #define PNG_INFO_iTXt 0x20000000U
    161 #define PNG_INFO_zTXt 0x40000000U
    162 
    163 #define PNG_INFO_sTER 0x01000000U
    164 #define PNG_INFO_vpAg 0x02000000U
    165 
    166 #define ABSENT  0
    167 #define START   1
    168 #define END     2
    169 
    170 static struct
    171 {
    172    char        name[5];
    173    png_uint_32 flag;
    174    png_uint_32 tag;
    175    int         unknown;    /* Chunk not known to libpng */
    176    int         all;        /* Chunk set by the '-1' option */
    177    int         position;   /* position in pngtest.png */
    178    int         keep;       /* unknown handling setting */
    179 } chunk_info[] = {
    180    /* Critical chunks */
    181    { "IDAT", PNG_INFO_IDAT, png_IDAT, 0, 0,  START, 0 }, /* must be [0] */
    182    { "PLTE", PNG_INFO_PLTE, png_PLTE, 0, 0, ABSENT, 0 },
    183 
    184    /* Non-critical chunks that libpng handles */
    185    /* This is a mess but it seems to be the only way to do it - there is no way
    186     * to check for a definition outside a #if.
    187     */
    188    { "bKGD", PNG_INFO_bKGD, png_bKGD,
    189 #     ifdef PNG_READ_bKGD_SUPPORTED
    190          0,
    191 #     else
    192          1,
    193 #     endif
    194       1,  START, 0 },
    195    { "cHRM", PNG_INFO_cHRM, png_cHRM,
    196 #     ifdef PNG_READ_cHRM_SUPPORTED
    197          0,
    198 #     else
    199          1,
    200 #     endif
    201       1,  START, 0 },
    202    { "gAMA", PNG_INFO_gAMA, png_gAMA,
    203 #     ifdef PNG_READ_gAMA_SUPPORTED
    204          0,
    205 #     else
    206          1,
    207 #     endif
    208       1,  START, 0 },
    209    { "hIST", PNG_INFO_hIST, png_hIST,
    210 #     ifdef PNG_READ_hIST_SUPPORTED
    211          0,
    212 #     else
    213          1,
    214 #     endif
    215       1, ABSENT, 0 },
    216    { "iCCP", PNG_INFO_iCCP, png_iCCP,
    217 #     ifdef PNG_READ_iCCP_SUPPORTED
    218          0,
    219 #     else
    220          1,
    221 #     endif
    222       1, ABSENT, 0 },
    223    { "iTXt", PNG_INFO_iTXt, png_iTXt,
    224 #     ifdef PNG_READ_iTXt_SUPPORTED
    225          0,
    226 #     else
    227          1,
    228 #     endif
    229       1, ABSENT, 0 },
    230    { "oFFs", PNG_INFO_oFFs, png_oFFs,
    231 #     ifdef PNG_READ_oFFs_SUPPORTED
    232          0,
    233 #     else
    234          1,
    235 #     endif
    236       1,  START, 0 },
    237    { "pCAL", PNG_INFO_pCAL, png_pCAL,
    238 #     ifdef PNG_READ_pCAL_SUPPORTED
    239          0,
    240 #     else
    241          1,
    242 #     endif
    243       1,  START, 0 },
    244    { "pHYs", PNG_INFO_pHYs, png_pHYs,
    245 #     ifdef PNG_READ_pHYs_SUPPORTED
    246          0,
    247 #     else
    248          1,
    249 #     endif
    250       1,  START, 0 },
    251    { "sBIT", PNG_INFO_sBIT, png_sBIT,
    252 #     ifdef PNG_READ_sBIT_SUPPORTED
    253          0,
    254 #     else
    255          1,
    256 #     endif
    257       1,  START, 0 },
    258    { "sCAL", PNG_INFO_sCAL, png_sCAL,
    259 #     ifdef PNG_READ_sCAL_SUPPORTED
    260          0,
    261 #     else
    262          1,
    263 #     endif
    264       1,  START, 0 },
    265    { "sPLT", PNG_INFO_sPLT, png_sPLT,
    266 #     ifdef PNG_READ_sPLT_SUPPORTED
    267          0,
    268 #     else
    269          1,
    270 #     endif
    271       1, ABSENT, 0 },
    272    { "sRGB", PNG_INFO_sRGB, png_sRGB,
    273 #     ifdef PNG_READ_sRGB_SUPPORTED
    274          0,
    275 #     else
    276          1,
    277 #     endif
    278       1,  START, 0 },
    279    { "tEXt", PNG_INFO_tEXt, png_tEXt,
    280 #     ifdef PNG_READ_tEXt_SUPPORTED
    281          0,
    282 #     else
    283          1,
    284 #     endif
    285       1,  START, 0 },
    286    { "tIME", PNG_INFO_tIME, png_tIME,
    287 #     ifdef PNG_READ_tIME_SUPPORTED
    288          0,
    289 #     else
    290          1,
    291 #     endif
    292       1,  START, 0 },
    293    { "tRNS", PNG_INFO_tRNS, png_tRNS,
    294 #     ifdef PNG_READ_tRNS_SUPPORTED
    295          0,
    296 #     else
    297          1,
    298 #     endif
    299       0, ABSENT, 0 },
    300    { "zTXt", PNG_INFO_zTXt, png_zTXt,
    301 #     ifdef PNG_READ_zTXt_SUPPORTED
    302          0,
    303 #     else
    304          1,
    305 #     endif
    306       1,    END, 0 },
    307 
    308    /* No libpng handling */
    309    { "sTER", PNG_INFO_sTER, png_sTER, 1, 1,  START, 0 },
    310    { "vpAg", PNG_INFO_vpAg, png_vpAg, 1, 0,  START, 0 },
    311 };
    312 
    313 #define NINFO ((int)((sizeof chunk_info)/(sizeof chunk_info[0])))
    314 
    315 static void
    316 clear_keep(void)
    317 {
    318    int i = NINFO;
    319    while (--i >= 0)
    320       chunk_info[i].keep = 0;
    321 }
    322 
    323 static int
    324 find(const char *name)
    325 {
    326    int i = NINFO;
    327    while (--i >= 0)
    328    {
    329       if (memcmp(chunk_info[i].name, name, 4) == 0)
    330          break;
    331    }
    332 
    333    return i;
    334 }
    335 
    336 static int
    337 findb(const png_byte *name)
    338 {
    339    int i = NINFO;
    340    while (--i >= 0)
    341    {
    342       if (memcmp(chunk_info[i].name, name, 4) == 0)
    343          break;
    344    }
    345 
    346    return i;
    347 }
    348 
    349 static int
    350 find_by_flag(png_uint_32 flag)
    351 {
    352    int i = NINFO;
    353 
    354    while (--i >= 0) if (chunk_info[i].flag == flag) return i;
    355 
    356    fprintf(stderr, "pngunknown: internal error\n");
    357    exit(4);
    358 }
    359 
    360 static int
    361 ancillary(const char *name)
    362 {
    363    return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
    364 }
    365 
    366 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
    367 static int
    368 ancillaryb(const png_byte *name)
    369 {
    370    return PNG_CHUNK_ANCILLARY(PNG_U32(name[0], name[1], name[2], name[3]));
    371 }
    372 #endif
    373 
    374 /* Type of an error_ptr */
    375 typedef struct
    376 {
    377    jmp_buf     error_return;
    378    png_structp png_ptr;
    379    png_infop   info_ptr, end_ptr;
    380    png_uint_32 before_IDAT;
    381    png_uint_32 after_IDAT;
    382    int         error_count;
    383    int         warning_count;
    384    int         keep; /* the default value */
    385    const char *program;
    386    const char *file;
    387    const char *test;
    388 } display;
    389 
    390 static const char init[] = "initialization";
    391 static const char cmd[] = "command line";
    392 
    393 static void
    394 init_display(display *d, const char *program)
    395 {
    396    memset(d, 0, sizeof *d);
    397    d->png_ptr = NULL;
    398    d->info_ptr = d->end_ptr = NULL;
    399    d->error_count = d->warning_count = 0;
    400    d->program = program;
    401    d->file = program;
    402    d->test = init;
    403 }
    404 
    405 static void
    406 clean_display(display *d)
    407 {
    408    png_destroy_read_struct(&d->png_ptr, &d->info_ptr, &d->end_ptr);
    409 
    410    /* This must not happen - it might cause an app crash */
    411    if (d->png_ptr != NULL || d->info_ptr != NULL || d->end_ptr != NULL)
    412    {
    413       fprintf(stderr, "%s(%s): png_destroy_read_struct error\n", d->file,
    414          d->test);
    415       exit(1);
    416    }
    417 }
    418 
    419 PNG_FUNCTION(void, display_exit, (display *d), static PNG_NORETURN)
    420 {
    421    ++(d->error_count);
    422 
    423    if (d->png_ptr != NULL)
    424       clean_display(d);
    425 
    426    /* During initialization and if this is a single command line argument set
    427     * exit now - there is only one test, otherwise longjmp to do the next test.
    428     */
    429    if (d->test == init || d->test == cmd)
    430       exit(1);
    431 
    432    longjmp(d->error_return, 1);
    433 }
    434 
    435 static int
    436 display_rc(const display *d, int strict)
    437 {
    438    return d->error_count + (strict ? d->warning_count : 0);
    439 }
    440 
    441 /* libpng error and warning callbacks */
    442 PNG_FUNCTION(void, (PNGCBAPI error), (png_structp png_ptr, const char *message),
    443    static PNG_NORETURN)
    444 {
    445    display *d = (display*)png_get_error_ptr(png_ptr);
    446 
    447    fprintf(stderr, "%s(%s): libpng error: %s\n", d->file, d->test, message);
    448    display_exit(d);
    449 }
    450 
    451 static void PNGCBAPI
    452 warning(png_structp png_ptr, const char *message)
    453 {
    454    display *d = (display*)png_get_error_ptr(png_ptr);
    455 
    456    fprintf(stderr, "%s(%s): libpng warning: %s\n", d->file, d->test, message);
    457    ++(d->warning_count);
    458 }
    459 
    460 static png_uint_32
    461 get_valid(display *d, png_infop info_ptr)
    462 {
    463    png_uint_32 flags = png_get_valid(d->png_ptr, info_ptr, (png_uint_32)~0);
    464 
    465    /* Map the text chunks back into the flags */
    466    {
    467       png_textp text;
    468       png_uint_32 ntext = png_get_text(d->png_ptr, info_ptr, &text, NULL);
    469 
    470       while (ntext-- > 0) switch (text[ntext].compression)
    471       {
    472          case -1:
    473             flags |= PNG_INFO_tEXt;
    474             break;
    475          case 0:
    476             flags |= PNG_INFO_zTXt;
    477             break;
    478          case 1:
    479          case 2:
    480             flags |= PNG_INFO_iTXt;
    481             break;
    482          default:
    483             fprintf(stderr, "%s(%s): unknown text compression %d\n", d->file,
    484                d->test, text[ntext].compression);
    485             display_exit(d);
    486       }
    487    }
    488 
    489    return flags;
    490 }
    491 
    492 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
    493 static int PNGCBAPI
    494 read_callback(png_structp pp, png_unknown_chunkp pc)
    495 {
    496    /* This function mimics the behavior of png_set_keep_unknown_chunks by
    497     * returning '0' to keep the chunk and '1' to discard it.
    498     */
    499    display *d = voidcast(display*, png_get_user_chunk_ptr(pp));
    500    int chunk = findb(pc->name);
    501    int keep, discard;
    502 
    503    if (chunk < 0) /* not one in our list, so not a known chunk */
    504       keep = d->keep;
    505 
    506    else
    507    {
    508       keep = chunk_info[chunk].keep;
    509       if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
    510       {
    511          /* See the comments in png.h - use the default for unknown chunks,
    512           * do not keep known chunks.
    513           */
    514          if (chunk_info[chunk].unknown)
    515             keep = d->keep;
    516 
    517          else
    518             keep = PNG_HANDLE_CHUNK_NEVER;
    519       }
    520    }
    521 
    522    switch (keep)
    523    {
    524       default:
    525          fprintf(stderr, "%s(%s): %d: unrecognized chunk option\n", d->file,
    526             d->test, chunk_info[chunk].keep);
    527          display_exit(d);
    528 
    529       case PNG_HANDLE_CHUNK_AS_DEFAULT:
    530       case PNG_HANDLE_CHUNK_NEVER:
    531          discard = 1/*handled; discard*/;
    532          break;
    533 
    534       case PNG_HANDLE_CHUNK_IF_SAFE:
    535       case PNG_HANDLE_CHUNK_ALWAYS:
    536          discard = 0/*not handled; keep*/;
    537          break;
    538    }
    539 
    540    /* Also store information about this chunk in the display, the relevant flag
    541     * is set if the chunk is to be kept ('not handled'.)
    542     */
    543    if (chunk >= 0) if (!discard) /* stupidity to stop a GCC warning */
    544    {
    545       png_uint_32 flag = chunk_info[chunk].flag;
    546 
    547       if (pc->location & PNG_AFTER_IDAT)
    548          d->after_IDAT |= flag;
    549 
    550       else
    551          d->before_IDAT |= flag;
    552    }
    553 
    554    /* However if there is no support to store unknown chunks don't ask libpng to
    555     * do it; there will be an png_error.
    556     */
    557 #  ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
    558       return discard;
    559 #  else
    560       return 1; /*handled; discard*/
    561 #  endif
    562 }
    563 #endif /* READ_USER_CHUNKS_SUPPORTED */
    564 
    565 #ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
    566 static png_uint_32
    567 get_unknown(display *d, png_infop info_ptr, int after_IDAT)
    568 {
    569    /* Create corresponding 'unknown' flags */
    570    png_uint_32 flags = 0;
    571 
    572    UNUSED(after_IDAT)
    573 
    574    {
    575       png_unknown_chunkp unknown;
    576       int num_unknown = png_get_unknown_chunks(d->png_ptr, info_ptr, &unknown);
    577 
    578       while (--num_unknown >= 0)
    579       {
    580          int chunk = findb(unknown[num_unknown].name);
    581 
    582          /* Chunks not known to pngunknown must be validated here; since they
    583           * must also be unknown to libpng the 'display->keep' behavior should
    584           * have been used.
    585           */
    586          if (chunk < 0) switch (d->keep)
    587          {
    588             default: /* impossible */
    589             case PNG_HANDLE_CHUNK_AS_DEFAULT:
    590             case PNG_HANDLE_CHUNK_NEVER:
    591                fprintf(stderr, "%s(%s): %s: %s: unknown chunk saved\n",
    592                   d->file, d->test, d->keep ? "discard" : "default",
    593                   unknown[num_unknown].name);
    594                ++(d->error_count);
    595                break;
    596 
    597             case PNG_HANDLE_CHUNK_IF_SAFE:
    598                if (!ancillaryb(unknown[num_unknown].name))
    599                {
    600                   fprintf(stderr,
    601                      "%s(%s): if-safe: %s: unknown critical chunk saved\n",
    602                      d->file, d->test, unknown[num_unknown].name);
    603                   ++(d->error_count);
    604                   break;
    605                }
    606                /* FALL THROUGH (safe) */
    607             case PNG_HANDLE_CHUNK_ALWAYS:
    608                break;
    609          }
    610 
    611          else
    612             flags |= chunk_info[chunk].flag;
    613       }
    614    }
    615 
    616    return flags;
    617 }
    618 #else
    619 static png_uint_32
    620 get_unknown(display *d, png_infop info_ptr, int after_IDAT)
    621    /* Otherwise this will return the cached values set by any user callback */
    622 {
    623    UNUSED(info_ptr);
    624 
    625    if (after_IDAT)
    626       return d->after_IDAT;
    627 
    628    else
    629       return d->before_IDAT;
    630 }
    631 
    632 #  ifndef PNG_READ_USER_CHUNKS_SUPPORTED
    633       /* The #defines above should mean this is never reached, it's just here as
    634        * a check to ensure the logic is correct.
    635        */
    636 #     error No store support and no user chunk support, this will not work
    637 #  endif
    638 #endif
    639 
    640 static int
    641 check(FILE *fp, int argc, const char **argv, png_uint_32p flags/*out*/,
    642    display *d, int set_callback)
    643 {
    644    int i, npasses, ipass;
    645    png_uint_32 height;
    646 
    647    d->keep = PNG_HANDLE_CHUNK_AS_DEFAULT;
    648    d->before_IDAT = 0;
    649    d->after_IDAT = 0;
    650 
    651    /* Some of these errors are permanently fatal and cause an exit here, others
    652     * are per-test and cause an error return.
    653     */
    654    d->png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, d, error,
    655       warning);
    656    if (d->png_ptr == NULL)
    657    {
    658       fprintf(stderr, "%s(%s): could not allocate png struct\n", d->file,
    659          d->test);
    660       /* Terminate here, this error is not test specific. */
    661       exit(1);
    662    }
    663 
    664    d->info_ptr = png_create_info_struct(d->png_ptr);
    665    d->end_ptr = png_create_info_struct(d->png_ptr);
    666    if (d->info_ptr == NULL || d->end_ptr == NULL)
    667    {
    668       fprintf(stderr, "%s(%s): could not allocate png info\n", d->file,
    669          d->test);
    670       clean_display(d);
    671       exit(1);
    672    }
    673 
    674    png_init_io(d->png_ptr, fp);
    675 
    676 #  ifdef PNG_READ_USER_CHUNKS_SUPPORTED
    677       /* This is only done if requested by the caller; it interferes with the
    678        * standard store/save mechanism.
    679        */
    680       if (set_callback)
    681          png_set_read_user_chunk_fn(d->png_ptr, d, read_callback);
    682 #  else
    683       UNUSED(set_callback)
    684 #  endif
    685 
    686    /* Handle each argument in turn; multiple settings are possible for the same
    687     * chunk and multiple calls will occur (the last one should override all
    688     * preceding ones).
    689     */
    690    for (i=0; i<argc; ++i)
    691    {
    692       const char *equals = strchr(argv[i], '=');
    693 
    694       if (equals != NULL)
    695       {
    696          int chunk, option;
    697 
    698          if (strcmp(equals+1, "default") == 0)
    699             option = PNG_HANDLE_CHUNK_AS_DEFAULT;
    700          else if (strcmp(equals+1, "discard") == 0)
    701             option = PNG_HANDLE_CHUNK_NEVER;
    702          else if (strcmp(equals+1, "if-safe") == 0)
    703             option = PNG_HANDLE_CHUNK_IF_SAFE;
    704          else if (strcmp(equals+1, "save") == 0)
    705             option = PNG_HANDLE_CHUNK_ALWAYS;
    706          else
    707          {
    708             fprintf(stderr, "%s(%s): %s: unrecognized chunk option\n", d->file,
    709                d->test, argv[i]);
    710             display_exit(d);
    711          }
    712 
    713          switch (equals - argv[i])
    714          {
    715             case 4: /* chunk name */
    716                chunk = find(argv[i]);
    717 
    718                if (chunk >= 0)
    719                {
    720                   /* These #if tests have the effect of skipping the arguments
    721                    * if SAVE support is unavailable - we can't do a useful test
    722                    * in this case, so we just check the arguments!  This could
    723                    * be improved in the future by using the read callback.
    724                    */
    725                   png_byte name[5];
    726 
    727                   memcpy(name, chunk_info[chunk].name, 5);
    728                   png_set_keep_unknown_chunks(d->png_ptr, option, name, 1);
    729                   chunk_info[chunk].keep = option;
    730                   continue;
    731                }
    732 
    733                break;
    734 
    735             case 7: /* default */
    736                if (memcmp(argv[i], "default", 7) == 0)
    737                {
    738                   png_set_keep_unknown_chunks(d->png_ptr, option, NULL, 0);
    739                   d->keep = option;
    740                   continue;
    741                }
    742 
    743                break;
    744 
    745             case 3: /* all */
    746                if (memcmp(argv[i], "all", 3) == 0)
    747                {
    748                   png_set_keep_unknown_chunks(d->png_ptr, option, NULL, -1);
    749                   d->keep = option;
    750 
    751                   for (chunk = 0; chunk < NINFO; ++chunk)
    752                      if (chunk_info[chunk].all)
    753                         chunk_info[chunk].keep = option;
    754                   continue;
    755                }
    756 
    757                break;
    758 
    759             default: /* some misplaced = */
    760 
    761                break;
    762          }
    763       }
    764 
    765       fprintf(stderr, "%s(%s): %s: unrecognized chunk argument\n", d->file,
    766          d->test, argv[i]);
    767       display_exit(d);
    768    }
    769 
    770    png_read_info(d->png_ptr, d->info_ptr);
    771 
    772    switch (png_get_interlace_type(d->png_ptr, d->info_ptr))
    773    {
    774       case PNG_INTERLACE_NONE:
    775          npasses = 1;
    776          break;
    777 
    778       case PNG_INTERLACE_ADAM7:
    779          npasses = PNG_INTERLACE_ADAM7_PASSES;
    780          break;
    781 
    782       default:
    783          /* Hard error because it is not test specific */
    784          fprintf(stderr, "%s(%s): invalid interlace type\n", d->file, d->test);
    785          clean_display(d);
    786          exit(1);
    787    }
    788 
    789    /* Skip the image data, if IDAT is not being handled then don't do this
    790     * because it will cause a CRC error.
    791     */
    792    if (chunk_info[0/*IDAT*/].keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
    793    {
    794       png_start_read_image(d->png_ptr);
    795       height = png_get_image_height(d->png_ptr, d->info_ptr);
    796 
    797       if (npasses > 1)
    798       {
    799          png_uint_32 width = png_get_image_width(d->png_ptr, d->info_ptr);
    800 
    801          for (ipass=0; ipass<npasses; ++ipass)
    802          {
    803             png_uint_32 wPass = PNG_PASS_COLS(width, ipass);
    804 
    805             if (wPass > 0)
    806             {
    807                png_uint_32 y;
    808 
    809                for (y=0; y<height; ++y) if (PNG_ROW_IN_INTERLACE_PASS(y, ipass))
    810                   png_read_row(d->png_ptr, NULL, NULL);
    811             }
    812          }
    813       } /* interlaced */
    814 
    815       else /* not interlaced */
    816       {
    817          png_uint_32 y;
    818 
    819          for (y=0; y<height; ++y)
    820             png_read_row(d->png_ptr, NULL, NULL);
    821       }
    822    }
    823 
    824    png_read_end(d->png_ptr, d->end_ptr);
    825 
    826    flags[0] = get_valid(d, d->info_ptr);
    827    flags[1] = get_unknown(d, d->info_ptr, 0/*before IDAT*/);
    828 
    829    /* Only png_read_png sets PNG_INFO_IDAT! */
    830    flags[chunk_info[0/*IDAT*/].keep != PNG_HANDLE_CHUNK_AS_DEFAULT] |=
    831       PNG_INFO_IDAT;
    832 
    833    flags[2] = get_valid(d, d->end_ptr);
    834    flags[3] = get_unknown(d, d->end_ptr, 1/*after IDAT*/);
    835 
    836    clean_display(d);
    837 
    838    return d->keep;
    839 }
    840 
    841 static void
    842 check_error(display *d, png_uint_32 flags, const char *message)
    843 {
    844    while (flags)
    845    {
    846       png_uint_32 flag = flags & -(png_int_32)flags;
    847       int i = find_by_flag(flag);
    848 
    849       fprintf(stderr, "%s(%s): chunk %s: %s\n", d->file, d->test,
    850          chunk_info[i].name, message);
    851       ++(d->error_count);
    852 
    853       flags &= ~flag;
    854    }
    855 }
    856 
    857 static void
    858 check_handling(display *d, int def, png_uint_32 chunks, png_uint_32 known,
    859    png_uint_32 unknown, const char *position, int set_callback)
    860 {
    861    while (chunks)
    862    {
    863       png_uint_32 flag = chunks & -(png_int_32)chunks;
    864       int i = find_by_flag(flag);
    865       int keep = chunk_info[i].keep;
    866       const char *type;
    867       const char *errorx = NULL;
    868 
    869       if (chunk_info[i].unknown)
    870       {
    871          if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT)
    872          {
    873             type = "UNKNOWN (default)";
    874             keep = def;
    875          }
    876 
    877          else
    878             type = "UNKNOWN (specified)";
    879 
    880          if (flag & known)
    881             errorx = "chunk processed";
    882 
    883          else switch (keep)
    884          {
    885             case PNG_HANDLE_CHUNK_AS_DEFAULT:
    886                if (flag & unknown)
    887                   errorx = "DEFAULT: unknown chunk saved";
    888                break;
    889 
    890             case PNG_HANDLE_CHUNK_NEVER:
    891                if (flag & unknown)
    892                   errorx = "DISCARD: unknown chunk saved";
    893                break;
    894 
    895             case PNG_HANDLE_CHUNK_IF_SAFE:
    896                if (ancillary(chunk_info[i].name))
    897                {
    898                   if (!(flag & unknown))
    899                      errorx = "IF-SAFE: unknown ancillary chunk lost";
    900                }
    901 
    902                else if (flag & unknown)
    903                   errorx = "IF-SAFE: unknown critical chunk saved";
    904                break;
    905 
    906             case PNG_HANDLE_CHUNK_ALWAYS:
    907                if (!(flag & unknown))
    908                   errorx = "SAVE: unknown chunk lost";
    909                break;
    910 
    911             default:
    912                errorx = "internal error: bad keep";
    913                break;
    914          }
    915       } /* unknown chunk */
    916 
    917       else /* known chunk */
    918       {
    919          type = "KNOWN";
    920 
    921          if (flag & known)
    922          {
    923             /* chunk was processed, it won't have been saved because that is
    924              * caught below when checking for inconsistent processing.
    925              */
    926             if (keep != PNG_HANDLE_CHUNK_AS_DEFAULT)
    927                errorx = "!DEFAULT: known chunk processed";
    928          }
    929 
    930          else /* not processed */ switch (keep)
    931          {
    932             case PNG_HANDLE_CHUNK_AS_DEFAULT:
    933                errorx = "DEFAULT: known chunk not processed";
    934                break;
    935 
    936             case PNG_HANDLE_CHUNK_NEVER:
    937                if (flag & unknown)
    938                   errorx = "DISCARD: known chunk saved";
    939                break;
    940 
    941             case PNG_HANDLE_CHUNK_IF_SAFE:
    942                if (ancillary(chunk_info[i].name))
    943                {
    944                   if (!(flag & unknown))
    945                      errorx = "IF-SAFE: known ancillary chunk lost";
    946                }
    947 
    948                else if (flag & unknown)
    949                   errorx = "IF-SAFE: known critical chunk saved";
    950                break;
    951 
    952             case PNG_HANDLE_CHUNK_ALWAYS:
    953                if (!(flag & unknown))
    954                   errorx = "SAVE: known chunk lost";
    955                break;
    956 
    957             default:
    958                errorx = "internal error: bad keep (2)";
    959                break;
    960          }
    961       }
    962 
    963       if (errorx != NULL)
    964       {
    965          ++(d->error_count);
    966          fprintf(stderr, "%s(%s%s): %s %s %s: %s\n", d->file, d->test,
    967             set_callback ? ",callback" : "",
    968             type, chunk_info[i].name, position, errorx);
    969       }
    970 
    971       chunks &= ~flag;
    972    }
    973 }
    974 
    975 static void
    976 perform_one_test(FILE *fp, int argc, const char **argv,
    977    png_uint_32 *default_flags, display *d, int set_callback)
    978 {
    979    int def;
    980    png_uint_32 flags[2][4];
    981 
    982    rewind(fp);
    983    clear_keep();
    984    memcpy(flags[0], default_flags, sizeof flags[0]);
    985 
    986    def = check(fp, argc, argv, flags[1], d, set_callback);
    987 
    988    /* Chunks should either be known or unknown, never both and this should apply
    989     * whether the chunk is before or after the IDAT (actually, the app can
    990     * probably change this by swapping the handling after the image, but this
    991     * test does not do that.)
    992     */
    993    check_error(d, (flags[0][0]|flags[0][2]) & (flags[0][1]|flags[0][3]),
    994       "chunk handled inconsistently in count tests");
    995    check_error(d, (flags[1][0]|flags[1][2]) & (flags[1][1]|flags[1][3]),
    996       "chunk handled inconsistently in option tests");
    997 
    998    /* Now find out what happened to each chunk before and after the IDAT and
    999     * determine if the behavior was correct.  First some basic sanity checks,
   1000     * any known chunk should be known in the original count, any unknown chunk
   1001     * should be either known or unknown in the original.
   1002     */
   1003    {
   1004       png_uint_32 test;
   1005 
   1006       test = flags[1][0] & ~flags[0][0];
   1007       check_error(d, test, "new known chunk before IDAT");
   1008       test = flags[1][1] & ~(flags[0][0] | flags[0][1]);
   1009       check_error(d, test, "new unknown chunk before IDAT");
   1010       test = flags[1][2] & ~flags[0][2];
   1011       check_error(d, test, "new known chunk after IDAT");
   1012       test = flags[1][3] & ~(flags[0][2] | flags[0][3]);
   1013       check_error(d, test, "new unknown chunk after IDAT");
   1014    }
   1015 
   1016    /* Now each chunk in the original list should have been handled according to
   1017     * the options set for that chunk, regardless of whether libpng knows about
   1018     * it or not.
   1019     */
   1020    check_handling(d, def, flags[0][0] | flags[0][1], flags[1][0], flags[1][1],
   1021       "before IDAT", set_callback);
   1022    check_handling(d, def, flags[0][2] | flags[0][3], flags[1][2], flags[1][3],
   1023       "after IDAT", set_callback);
   1024 }
   1025 
   1026 static void
   1027 perform_one_test_safe(FILE *fp, int argc, const char **argv,
   1028    png_uint_32 *default_flags, display *d, const char *test)
   1029 {
   1030    if (setjmp(d->error_return) == 0)
   1031    {
   1032       d->test = test; /* allow use of d->error_return */
   1033 #     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
   1034          perform_one_test(fp, argc, argv, default_flags, d, 0);
   1035 #     endif
   1036 #     ifdef PNG_READ_USER_CHUNKS_SUPPORTED
   1037          perform_one_test(fp, argc, argv, default_flags, d, 1);
   1038 #     endif
   1039       d->test = init; /* prevent use of d->error_return */
   1040    }
   1041 }
   1042 
   1043 static const char *standard_tests[] =
   1044 {
   1045  "discard", "default=discard", 0,
   1046  "save", "default=save", 0,
   1047  "if-safe", "default=if-safe", 0,
   1048  "vpAg", "vpAg=if-safe", 0,
   1049  "sTER", "sTER=if-safe", 0,
   1050  "IDAT", "default=discard", "IDAT=save", 0,
   1051  "sAPI", "bKGD=save", "cHRM=save", "gAMA=save", "all=discard", "iCCP=save",
   1052    "sBIT=save", "sRGB=save", 0,
   1053  0/*end*/
   1054 };
   1055 
   1056 static PNG_NORETURN void
   1057 usage(const char *program, const char *reason)
   1058 {
   1059    fprintf(stderr, "pngunknown: %s: usage:\n %s [--strict] "
   1060       "--default|{(CHNK|default|all)=(default|discard|if-safe|save)} "
   1061       "testfile.png\n", reason, program);
   1062    exit(99);
   1063 }
   1064 
   1065 int
   1066 main(int argc, const char **argv)
   1067 {
   1068    FILE *fp;
   1069    png_uint_32 default_flags[4/*valid,unknown{before,after}*/];
   1070    int strict = 0, default_tests = 0;
   1071    const char *count_argv = "default=save";
   1072    const char *touch_file = NULL;
   1073    display d;
   1074 
   1075    init_display(&d, argv[0]);
   1076 
   1077    while (++argv, --argc > 0)
   1078    {
   1079       if (strcmp(*argv, "--strict") == 0)
   1080          strict = 1;
   1081 
   1082       else if (strcmp(*argv, "--default") == 0)
   1083          default_tests = 1;
   1084 
   1085       else if (strcmp(*argv, "--touch") == 0)
   1086       {
   1087          if (argc > 1)
   1088             touch_file = *++argv, --argc;
   1089 
   1090          else
   1091             usage(d.program, "--touch: missing file name");
   1092       }
   1093 
   1094       else
   1095          break;
   1096    }
   1097 
   1098    /* A file name is required, but there should be no other arguments if
   1099     * --default was specified.
   1100     */
   1101    if (argc <= 0)
   1102       usage(d.program, "missing test file");
   1103 
   1104    /* GCC BUG: if (default_tests && argc != 1) triggers some weird GCC argc
   1105     * optimization which causes warnings with -Wstrict-overflow!
   1106     */
   1107    else if (default_tests) if (argc != 1)
   1108       usage(d.program, "extra arguments");
   1109 
   1110    /* The name of the test file is the last argument; remove it. */
   1111    d.file = argv[--argc];
   1112 
   1113    fp = fopen(d.file, "rb");
   1114    if (fp == NULL)
   1115    {
   1116       perror(d.file);
   1117       exit(99);
   1118    }
   1119 
   1120    /* First find all the chunks, known and unknown, in the test file, a failure
   1121     * here aborts the whole test.
   1122     *
   1123     * If 'save' is supported then the normal saving method should happen,
   1124     * otherwise if 'read' is supported then the read callback will do the
   1125     * same thing.  If both are supported the 'read' callback won't be
   1126     * instantiated by default.  If 'save' is *not* supported then a user
   1127     * callback is required even though we can call png_get_unknown_chunks.
   1128     */
   1129    if (check(fp, 1, &count_argv, default_flags, &d,
   1130 #     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
   1131          0
   1132 #     else
   1133          1
   1134 #     endif
   1135       ) != PNG_HANDLE_CHUNK_ALWAYS)
   1136    {
   1137       fprintf(stderr, "%s: %s: internal error\n", d.program, d.file);
   1138       exit(99);
   1139    }
   1140 
   1141    /* Now find what the various supplied options cause to change: */
   1142    if (!default_tests)
   1143    {
   1144       d.test = cmd; /* acts as a flag to say exit, do not longjmp */
   1145 #     ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED
   1146          perform_one_test(fp, argc, argv, default_flags, &d, 0);
   1147 #     endif
   1148 #     ifdef PNG_READ_USER_CHUNKS_SUPPORTED
   1149          perform_one_test(fp, argc, argv, default_flags, &d, 1);
   1150 #     endif
   1151       d.test = init;
   1152    }
   1153 
   1154    else
   1155    {
   1156       const char **test = standard_tests;
   1157 
   1158       /* Set the exit_test pointer here so we can continue after a libpng error.
   1159        * NOTE: this leaks memory because the png_struct data from the failing
   1160        * test is never freed.
   1161        */
   1162       while (*test)
   1163       {
   1164          const char *this_test = *test++;
   1165          const char **next = test;
   1166          int count = display_rc(&d, strict), new_count;
   1167          const char *result;
   1168          int arg_count = 0;
   1169 
   1170          while (*next) ++next, ++arg_count;
   1171 
   1172          perform_one_test_safe(fp, arg_count, test, default_flags, &d,
   1173             this_test);
   1174 
   1175          new_count = display_rc(&d, strict);
   1176 
   1177          if (new_count == count)
   1178             result = "PASS";
   1179 
   1180          else
   1181             result = "FAIL";
   1182 
   1183          printf("%s: %s %s\n", result, d.program, this_test);
   1184 
   1185          test = next+1;
   1186       }
   1187    }
   1188 
   1189    fclose(fp);
   1190 
   1191    if (display_rc(&d, strict) == 0)
   1192    {
   1193       /* Success, touch the success file if appropriate */
   1194       if (touch_file != NULL)
   1195       {
   1196          FILE *fsuccess = fopen(touch_file, "wt");
   1197 
   1198          if (fsuccess != NULL)
   1199          {
   1200             int err = 0;
   1201             fprintf(fsuccess, "PNG unknown tests succeeded\n");
   1202             fflush(fsuccess);
   1203             err = ferror(fsuccess);
   1204 
   1205             if (fclose(fsuccess) || err)
   1206             {
   1207                fprintf(stderr, "%s: write failed\n", touch_file);
   1208                exit(99);
   1209             }
   1210          }
   1211 
   1212          else
   1213          {
   1214             fprintf(stderr, "%s: open failed\n", touch_file);
   1215             exit(99);
   1216          }
   1217       }
   1218 
   1219       return 0;
   1220    }
   1221 
   1222    return 1;
   1223 }
   1224 
   1225 #else /* !(READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS) */
   1226 int
   1227 main(void)
   1228 {
   1229    fprintf(stderr,
   1230       " test ignored: no support to find out about unknown chunks\n");
   1231    /* So the test is skipped: */
   1232    return 77;
   1233 }
   1234 #endif /* READ_USER_CHUNKS || SAVE_UNKNOWN_CHUNKS */
   1235 
   1236 #else /* !(SET_UNKNOWN_CHUNKS && READ) */
   1237 int
   1238 main(void)
   1239 {
   1240    fprintf(stderr,
   1241       " test ignored: no support to modify unknown chunk handling\n");
   1242    /* So the test is skipped: */
   1243    return 77;
   1244 }
   1245 #endif /* SET_UNKNOWN_CHUNKS && READ*/
   1246