pack-write.c

   1 #include "cache.h"
   2 #include "pack.h"
   3
   4 void fixup_pack_header_footer(int pack_fd,
   5                          unsigned char *pack_file_sha1,
   6                          const char *pack_name,
   7                          uint32_t object_count)
   8 {
   9         static const int buf_sz = 128 * 1024;
  10         SHA_CTX c;
  11         struct pack_header hdr;
  12         char *buf;
  13
  14         if (lseek(pack_fd, 0, SEEK_SET) != 0)
  15                 die("Failed seeking to start: %s", strerror(errno));
  16         if (read_in_full(pack_fd, &hdr, sizeof(hdr)) != sizeof(hdr))
  17                 die("Unable to reread header of %s: %s", pack_name, strerror(errno));
  18         if (lseek(pack_fd, 0, SEEK_SET) != 0)
  19                 die("Failed seeking to start: %s", strerror(errno));
  20         hdr.hdr_entries = htonl(object_count);
  21         write_or_die(pack_fd, &hdr, sizeof(hdr));
  22
  23         SHA1_Init(&c);
  24         SHA1_Update(&c, &hdr, sizeof(hdr));
  25
  26         buf = xmalloc(buf_sz);
  27         for (;;) {
  28                 ssize_t n = xread(pack_fd, buf, buf_sz);
  29                 if (!n)
  30                         break;
  31                 if (n < 0)
  32                         die("Failed to checksum %s: %s", pack_name, strerror(errno));
  33                 SHA1_Update(&c, buf, n);
  34         }
  35         free(buf);
  36
  37         SHA1_Final(pack_file_sha1, &c);
  38         write_or_die(pack_fd, pack_file_sha1, 20);
  39 }