pd.if.org Git - zpackage/blob - lib/uncompress.c

   1 #include <stdio.h>
   2 #include <sys/types.h>
   3 #include <sys/stat.h>
   4 #include <fcntl.h>
   5 #include <unistd.h>
   6 #include <errno.h>
   7
   8 #include <sys/mman.h>
   9
  10 #include "sha256.h"
  11
  12 #include "lzma.h"
  13
  14 void uncompresslzma(void *buf, size_t bufsize, FILE *out) {
  15         lzma_stream s = LZMA_STREAM_INIT;
  16         lzma_stream *strm;
  17
  18         uint8_t outbuf[BUFSIZ];
  19
  20         int ret;
  21
  22         strm = &s;
  23
  24         ret = lzma_stream_decoder(strm, UINT64_MAX, 0);
  25         /* The only reasonable error here is LZMA_MEM_ERROR. */
  26         if (ret != LZMA_OK) {
  27                 fprintf(stderr, "%s", ret == LZMA_MEM_ERROR ? strerror(ENOMEM)
  28                                 : "Internal error (bug)");
  29                 exit(EXIT_FAILURE);
  30         }
  31
  32         strm->avail_in = bufsize;
  33         strm->next_in = buf;
  34         strm->avail_out = BUFSIZ;
  35         strm->next_out = outbuf;
  36
  37         lzma_action action = LZMA_RUN;
  38
  39         while (1) {
  40                 ret = lzma_code(strm, action);
  41
  42                 // Write and check write error before checking decoder error.
  43                 // This way as much data as possible gets written to output
  44                 // even if decoder detected an error.
  45                 if (strm->avail_out == 0 || ret != LZMA_OK) {
  46                         const size_t write_size = BUFSIZ - strm->avail_out;
  47
  48                         if (fwrite(outbuf, 1, write_size, out) != write_size) {
  49                                 // Wouldn't be a surprise if writing to stderr
  50                                 // would fail too but at least try to show an
  51                                 // error message.
  52                                 fprintf(stderr, "Cannot write to output file stream: "
  53                                                 "%s", strerror(errno));
  54                                 exit(EXIT_FAILURE);
  55                         }
  56
  57                         strm->next_out = outbuf;
  58                         strm->avail_out = BUFSIZ;
  59                 }
  60
  61                 if (ret != LZMA_OK) {
  62                         if (ret == LZMA_STREAM_END) {
  63                                 // lzma_stream_decoder() already guarantees
  64                                 // that there's no trailing garbage.
  65                                 assert(strm->avail_in == 0);
  66                                 //assert(action == LZMA_FINISH);
  67                                 return;
  68                         }
  69
  70                         const char *msg;
  71                         switch (ret) {
  72                                 case LZMA_MEM_ERROR:
  73                                         msg = strerror(ENOMEM);
  74                                         break;
  75
  76                                 case LZMA_FORMAT_ERROR:
  77                                         msg = "File format not recognized";
  78                                         break;
  79
  80                                 case LZMA_OPTIONS_ERROR:
  81                                         // FIXME: Better message?
  82                                         msg = "Unsupported compression options";
  83                                         break;
  84
  85                                 case LZMA_DATA_ERROR:
  86                                         msg = "File is corrupt";
  87                                         break;
  88
  89                                 case LZMA_BUF_ERROR:
  90                                         msg = "Unexpected end of input";
  91                                         break;
  92
  93                                 default:
  94                                         msg = "Internal error (bug)";
  95                                         break;
  96                         }
  97
  98                         fprintf(stderr, "xz: %s\n", msg);
  99                         exit(EXIT_FAILURE);
 100                 }
 101         }
 102 }