Home | History | Annotate | Download | only in fec 
      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 extern "C" {
     18     #include <fec.h>
     19 }
     20 
     21 #undef NDEBUG
     22 
     23 #include <assert.h>
     24 #include <errno.h>
     25 #include <getopt.h>
     26 #include <fcntl.h>
     27 #include <pthread.h>
     28 #include <stdbool.h>
     29 #include <stdlib.h>
     30 #include <string.h>
     31 
     32 #include <android-base/file.h>
     33 #include "image.h"
     34 
     35 enum {
     36     MODE_ENCODE,
     37     MODE_DECODE,
     38     MODE_PRINTSIZE,
     39     MODE_GETECCSTART,
     40     MODE_GETVERITYSTART
     41 };
     42 
     43 static void encode_rs(struct image_proc_ctx *ctx)
     44 {
     45     struct image *fcx = ctx->ctx;
     46     int j;
     47     uint8_t data[fcx->rs_n];
     48     uint64_t i;
     49 
     50     for (i = ctx->start; i < ctx->end; i += fcx->rs_n) {
     51         for (j = 0; j < fcx->rs_n; ++j) {
     52             data[j] = image_get_interleaved_byte(i + j, fcx);
     53         }
     54 
     55         encode_rs_char(ctx->rs, data, &fcx->fec[ctx->fec_pos]);
     56         ctx->fec_pos += fcx->roots;
     57     }
     58 }
     59 
     60 static void decode_rs(struct image_proc_ctx *ctx)
     61 {
     62     struct image *fcx = ctx->ctx;
     63     int j, rv;
     64     uint8_t data[fcx->rs_n + fcx->roots];
     65     uint64_t i;
     66 
     67     assert(sizeof(data) == FEC_RSM);
     68 
     69     for (i = ctx->start; i < ctx->end; i += fcx->rs_n) {
     70         for (j = 0; j < fcx->rs_n; ++j) {
     71             data[j] = image_get_interleaved_byte(i + j, fcx);
     72         }
     73 
     74         memcpy(&data[fcx->rs_n], &fcx->fec[ctx->fec_pos], fcx->roots);
     75         rv = decode_rs_char(ctx->rs, data, NULL, 0);
     76 
     77         if (rv < 0) {
     78             FATAL("failed to recover [%" PRIu64 ", %" PRIu64 ")\n",
     79                 i, i + fcx->rs_n);
     80         } else if (rv > 0) {
     81             /* copy corrected data to output */
     82             for (j = 0; j < fcx->rs_n; ++j) {
     83                 image_set_interleaved_byte(i + j, fcx, data[j]);
     84             }
     85 
     86             ctx->rv += rv;
     87         }
     88 
     89         ctx->fec_pos += fcx->roots;
     90     }
     91 }
     92 
     93 static int usage()
     94 {
     95     printf("fec: a tool for encoding and decoding files using RS(255, N).\n"
     96            "\n"
     97            "usage: fec <mode> [ <options> ] [ <data> <fec> [ <output> ] ]\n"
     98            "mode:\n"
     99            "  -e  --encode                      encode (default)\n"
    100            "  -d  --decode                      decode\n"
    101            "  -s, --print-fec-size=<data size>  print FEC size\n"
    102            "  -E, --get-ecc-start=data          print ECC offset in data\n"
    103            "  -V, --get-verity-start=data       print verity offset\n"
    104            "options:\n"
    105            "  -h                                show this help\n"
    106            "  -v                                enable verbose logging\n"
    107            "  -r, --roots=<bytes>               number of parity bytes\n"
    108            "  -m, --mmap                        use memory mapping\n"
    109            "  -j, --threads=<threads>           number of threads to use\n"
    110            "  -S                                treat data as a sparse file\n"
    111            "decoding options:\n"
    112            "  -i, --inplace                     correct <data> in place\n"
    113         );
    114 
    115     return 1;
    116 }
    117 
    118 static uint64_t parse_arg(const char *arg, const char *name, uint64_t maxval)
    119 {
    120     char* endptr;
    121     errno = 0;
    122 
    123     unsigned long long int value = strtoull(arg, &endptr, 0);
    124 
    125     if (arg[0] == '\0' || *endptr != '\0' ||
    126             (errno == ERANGE && value == ULLONG_MAX)) {
    127         FATAL("invalid value of %s\n", name);
    128     }
    129     if (value > maxval) {
    130         FATAL("value of roots too large (max. %" PRIu64 ")\n", maxval);
    131     }
    132 
    133     return (uint64_t)value;
    134 }
    135 
    136 static int print_size(image& ctx)
    137 {
    138     /* output size including header */
    139     printf("%" PRIu64 "\n", fec_ecc_get_size(ctx.inp_size, ctx.roots));
    140     return 0;
    141 }
    142 
    143 static int get_start(int mode, const std::string& filename)
    144 {
    145     fec::io fh(filename, O_RDONLY, FEC_VERITY_DISABLE);
    146 
    147     if (!fh) {
    148         FATAL("failed to open input\n");
    149     }
    150 
    151     if (mode == MODE_GETECCSTART) {
    152         fec_ecc_metadata data;
    153 
    154         if (!fh.get_ecc_metadata(data)) {
    155             FATAL("no ecc data\n");
    156         }
    157 
    158         printf("%" PRIu64 "\n", data.start);
    159     } else {
    160         fec_verity_metadata data;
    161 
    162         if (!fh.get_verity_metadata(data)) {
    163             FATAL("no verity data\n");
    164         }
    165 
    166         printf("%" PRIu64 "\n", data.data_size);
    167     }
    168 
    169     return 0;
    170 }
    171 
    172 static int encode(image& ctx, const std::vector<std::string>& inp_filenames,
    173         const std::string& fec_filename)
    174 {
    175     if (ctx.inplace) {
    176         FATAL("invalid parameters: inplace can only used when decoding\n");
    177     }
    178 
    179     if (!image_load(inp_filenames, &ctx, false)) {
    180         FATAL("failed to read input\n");
    181     }
    182 
    183     if (!image_ecc_new(fec_filename, &ctx)) {
    184         FATAL("failed to allocate ecc\n");
    185     }
    186 
    187     INFO("encoding RS(255, %d) to '%s' for input files:\n", ctx.rs_n,
    188         fec_filename.c_str());
    189 
    190     size_t n = 1;
    191 
    192     for (auto fn : inp_filenames) {
    193         INFO("\t%zu: '%s'\n", n++, fn.c_str());
    194     }
    195 
    196     if (ctx.verbose) {
    197         INFO("\traw fec size: %u\n", ctx.fec_size);
    198         INFO("\tblocks: %" PRIu64 "\n", ctx.blocks);
    199         INFO("\trounds: %" PRIu64 "\n", ctx.rounds);
    200     }
    201 
    202     if (!image_process(encode_rs, &ctx)) {
    203         FATAL("failed to process input\n");
    204     }
    205 
    206     if (!image_ecc_save(&ctx)) {
    207         FATAL("failed to write output\n");
    208     }
    209 
    210     image_free(&ctx);
    211     return 0;
    212 }
    213 
    214 static int decode(image& ctx, const std::vector<std::string>& inp_filenames,
    215         const std::string& fec_filename, std::string& out_filename)
    216 {
    217     const std::string& inp_filename = inp_filenames.front();
    218 
    219     if (ctx.inplace && ctx.sparse) {
    220         FATAL("invalid parameters: inplace cannot be used with sparse "
    221             "files\n");
    222     }
    223 
    224     if (!image_ecc_load(fec_filename, &ctx) ||
    225             !image_load(inp_filenames, &ctx, !out_filename.empty())) {
    226         FATAL("failed to read input\n");
    227     }
    228 
    229     if (ctx.inplace) {
    230         INFO("correcting '%s' using RS(255, %d) from '%s'\n",
    231             inp_filename.c_str(), ctx.rs_n, fec_filename.c_str());
    232 
    233         out_filename = inp_filename;
    234     } else {
    235         INFO("decoding '%s' to '%s' using RS(255, %d) from '%s'\n",
    236             inp_filename.c_str(),
    237             out_filename.empty() ? out_filename.c_str() : "<none>", ctx.rs_n,
    238             fec_filename.c_str());
    239     }
    240 
    241     if (ctx.verbose) {
    242         INFO("\traw fec size: %u\n", ctx.fec_size);
    243         INFO("\tblocks: %" PRIu64 "\n", ctx.blocks);
    244         INFO("\trounds: %" PRIu64 "\n", ctx.rounds);
    245     }
    246 
    247     if (!image_process(decode_rs, &ctx)) {
    248         FATAL("failed to process input\n");
    249     }
    250 
    251     if (ctx.rv) {
    252         INFO("corrected %" PRIu64 " errors\n", ctx.rv);
    253     } else {
    254         INFO("no errors found\n");
    255     }
    256 
    257     if (!out_filename.empty() && !image_save(out_filename, &ctx)) {
    258         FATAL("failed to write output\n");
    259     }
    260 
    261     image_free(&ctx);
    262     return 0;
    263 }
    264 
    265 int main(int argc, char **argv)
    266 {
    267     std::string fec_filename;
    268     std::string out_filename;
    269     std::vector<std::string> inp_filenames;
    270     int mode = MODE_ENCODE;
    271     image ctx;
    272 
    273     image_init(&ctx);
    274     ctx.roots = FEC_DEFAULT_ROOTS;
    275 
    276     while (1) {
    277         const static struct option long_options[] = {
    278             {"help", no_argument, 0, 'h'},
    279             {"encode", no_argument, 0, 'e'},
    280             {"decode", no_argument, 0, 'd'},
    281             {"sparse", no_argument, 0, 'S'},
    282             {"roots", required_argument, 0, 'r'},
    283             {"inplace", no_argument, 0, 'i'},
    284             {"mmap", no_argument, 0, 'm'},
    285             {"threads", required_argument, 0, 'j'},
    286             {"print-fec-size", required_argument, 0, 's'},
    287             {"get-ecc-start", required_argument, 0, 'E'},
    288             {"get-verity-start", required_argument, 0, 'V'},
    289             {"verbose", no_argument, 0, 'v'},
    290             {NULL, 0, 0, 0}
    291         };
    292         int c = getopt_long(argc, argv, "hedSr:imj:s:E:V:v", long_options, NULL);
    293         if (c < 0) {
    294             break;
    295         }
    296 
    297         switch (c) {
    298         case 'h':
    299             return usage();
    300         case 'S':
    301             ctx.sparse = true;
    302             break;
    303         case 'e':
    304             if (mode != MODE_ENCODE) {
    305                 return usage();
    306             }
    307             break;
    308         case 'd':
    309             if (mode != MODE_ENCODE) {
    310                 return usage();
    311             }
    312             mode = MODE_DECODE;
    313             break;
    314         case 'r':
    315             ctx.roots = (int)parse_arg(optarg, "roots", FEC_RSM);
    316             break;
    317         case 'i':
    318             ctx.inplace = true;
    319             break;
    320         case 'm':
    321             ctx.mmap = true;
    322             break;
    323         case 'j':
    324             ctx.threads = (int)parse_arg(optarg, "threads", IMAGE_MAX_THREADS);
    325             break;
    326         case 's':
    327             if (mode != MODE_ENCODE) {
    328                 return usage();
    329             }
    330             mode = MODE_PRINTSIZE;
    331             ctx.inp_size = parse_arg(optarg, "print-fec-size", UINT64_MAX);
    332             break;
    333         case 'E':
    334             if (mode != MODE_ENCODE) {
    335                 return usage();
    336             }
    337             mode = MODE_GETECCSTART;
    338             inp_filenames.push_back(optarg);
    339             break;
    340         case 'V':
    341             if (mode != MODE_ENCODE) {
    342                 return usage();
    343             }
    344             mode = MODE_GETVERITYSTART;
    345             inp_filenames.push_back(optarg);
    346             break;
    347         case 'v':
    348             ctx.verbose = true;
    349             break;
    350         case '?':
    351             return usage();
    352         default:
    353             abort();
    354         }
    355     }
    356 
    357     argc -= optind;
    358     argv += optind;
    359 
    360     assert(ctx.roots > 0 && ctx.roots < FEC_RSM);
    361 
    362     /* check for input / output parameters */
    363     if (mode == MODE_ENCODE) {
    364         /* allow multiple input files */
    365         for (int i = 0; i < (argc - 1); ++i) {
    366             inp_filenames.push_back(argv[i]);
    367         }
    368 
    369         if (inp_filenames.empty()) {
    370             return usage();
    371         }
    372 
    373         /* the last one is the output file */
    374         fec_filename = argv[argc - 1];
    375     } else if (mode == MODE_DECODE) {
    376         if (argc < 2 || argc > 3) {
    377             return usage();
    378         } else if (argc == 3) {
    379             if (ctx.inplace) {
    380                 return usage();
    381             }
    382             out_filename = argv[2];
    383         }
    384 
    385         inp_filenames.push_back(argv[0]);
    386         fec_filename = argv[1];
    387     }
    388 
    389     switch (mode) {
    390     case MODE_PRINTSIZE:
    391         return print_size(ctx);
    392     case MODE_GETECCSTART:
    393     case MODE_GETVERITYSTART:
    394         return get_start(mode, inp_filenames.front());
    395     case MODE_ENCODE:
    396         return encode(ctx, inp_filenames, fec_filename);
    397     case MODE_DECODE:
    398         return decode(ctx, inp_filenames, fec_filename, out_filename);
    399     default:
    400         abort();
    401     }
    402 
    403     return 1;
    404 }
    405