pack-check.c

   1 #include "cache.h"
   2 #include "pack.h"
   3
   4 #define BATCH (1u<<20)
   5
   6 static int verify_packfile(struct packed_git *p)
   7 {
   8         unsigned long index_size = p->index_size;
   9         const unsigned char *index_base = p->index_data;
  10         SHA_CTX ctx;
  11         unsigned char sha1[20];
  12         struct pack_header *hdr;
  13         int nr_objects, err, i;
  14         unsigned char *packdata;
  15         unsigned long datasize;
  16
  17         /* Header consistency check */
  18         hdr = p->pack_base;
  19         if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
  20                 return error("Packfile %s signature mismatch", p->pack_name);
  21         if (!pack_version_ok(hdr->hdr_version))
  22                 return error("Packfile version %d unsupported",
  23                              ntohl(hdr->hdr_version));
  24         nr_objects = ntohl(hdr->hdr_entries);
  25         if (num_packed_objects(p) != nr_objects)
  26                 return error("Packfile claims to have %d objects, "
  27                              "while idx size expects %d", nr_objects,
  28                              num_packed_objects(p));
  29
  30         /* Check integrity of pack data with its SHA-1 checksum */
  31         SHA1_Init(&ctx);
  32         packdata = p->pack_base;
  33         datasize = p->pack_size - 20;
  34         while (datasize) {
  35                 unsigned long batch = (datasize < BATCH) ? datasize : BATCH;
  36                 SHA1_Update(&ctx, packdata, batch);
  37                 datasize -= batch;
  38                 packdata += batch;
  39         }
  40         SHA1_Final(sha1, &ctx);
  41
  42         if (hashcmp(sha1, (unsigned char *)(p->pack_base) + p->pack_size - 20))
  43                 return error("Packfile %s SHA1 mismatch with itself",
  44                              p->pack_name);
  45         if (hashcmp(sha1, index_base + index_size - 40))
  46                 return error("Packfile %s SHA1 mismatch with idx",
  47                              p->pack_name);
  48
  49         /* Make sure everything reachable from idx is valid.  Since we
  50          * have verified that nr_objects matches between idx and pack,
  51          * we do not do scan-streaming check on the pack file.
  52          */
  53         for (i = err = 0; i < nr_objects; i++) {
  54                 const unsigned char *sha1;
  55                 void *data;
  56                 char type[20];
  57                 unsigned long size, offset;
  58
  59                 sha1 = nth_packed_object_sha1(p, i);
  60                 if (!sha1)
  61                         die("internal error pack-check nth-packed-object");
  62                 offset = find_pack_entry_one(sha1, p);
  63                 if (!offset)
  64                         die("internal error pack-check find-pack-entry-one");
  65                 data = unpack_entry_gently(p, offset, type, &size);
  66                 if (!data) {
  67                         err = error("cannot unpack %s from %s",
  68                                     sha1_to_hex(sha1), p->pack_name);
  69                         continue;
  70                 }
  71                 if (check_sha1_signature(sha1, data, size, type)) {
  72                         err = error("packed %s from %s is corrupt",
  73                                     sha1_to_hex(sha1), p->pack_name);
  74                         free(data);
  75                         continue;
  76                 }
  77                 free(data);
  78         }
  79
  80         return err;
  81 }
  82
  83
  84 #define MAX_CHAIN 40
  85
  86 static void show_pack_info(struct packed_git *p)
  87 {
  88         struct pack_header *hdr;
  89         int nr_objects, i;
  90         unsigned int chain_histogram[MAX_CHAIN];
  91
  92         hdr = p->pack_base;
  93         nr_objects = ntohl(hdr->hdr_entries);
  94         memset(chain_histogram, 0, sizeof(chain_histogram));
  95
  96         for (i = 0; i < nr_objects; i++) {
  97                 const unsigned char *sha1;
  98                 unsigned char base_sha1[20];
  99                 char type[20];
 100                 unsigned long size;
 101                 unsigned long store_size;
 102                 unsigned long offset;
 103                 unsigned int delta_chain_length;
 104
 105                 sha1 = nth_packed_object_sha1(p, i);
 106                 if (!sha1)
 107                         die("internal error pack-check nth-packed-object");
 108                 offset = find_pack_entry_one(sha1, p);
 109                 if (!offset)
 110                         die("internal error pack-check find-pack-entry-one");
 111
 112                 packed_object_info_detail(p, offset, type, &size, &store_size,
 113                                           &delta_chain_length,
 114                                           base_sha1);
 115                 printf("%s ", sha1_to_hex(sha1));
 116                 if (!delta_chain_length)
 117                         printf("%-6s %lu %lu\n", type, size, offset);
 118                 else {
 119                         printf("%-6s %lu %lu %u %s\n", type, size, offset,
 120                                delta_chain_length, sha1_to_hex(base_sha1));
 121                         if (delta_chain_length < MAX_CHAIN)
 122                                 chain_histogram[delta_chain_length]++;
 123                         else
 124                                 chain_histogram[0]++;
 125                 }
 126         }
 127
 128         for (i = 0; i < MAX_CHAIN; i++) {
 129                 if (!chain_histogram[i])
 130                         continue;
 131                 printf("chain length %s %d: %d object%s\n",
 132                        i ? "=" : ">=",
 133                        i ? i : MAX_CHAIN,
 134                        chain_histogram[i],
 135                        1 < chain_histogram[i] ? "s" : "");
 136         }
 137 }
 138
 139 int verify_pack(struct packed_git *p, int verbose)
 140 {
 141         unsigned long index_size = p->index_size;
 142         const unsigned char *index_base = p->index_data;
 143         SHA_CTX ctx;
 144         unsigned char sha1[20];
 145         int ret;
 146
 147         ret = 0;
 148         /* Verify SHA1 sum of the index file */
 149         SHA1_Init(&ctx);
 150         SHA1_Update(&ctx, index_base, index_size - 20);
 151         SHA1_Final(sha1, &ctx);
 152         if (hashcmp(sha1, index_base + index_size - 20))
 153                 ret = error("Packfile index for %s SHA1 mismatch",
 154                             p->pack_name);
 155
 156         if (!ret) {
 157                 /* Verify pack file */
 158                 use_packed_git(p);
 159                 ret = verify_packfile(p);
 160                 unuse_packed_git(p);
 161         }
 162
 163         if (verbose) {
 164                 if (ret)
 165                         printf("%s: bad\n", p->pack_name);
 166                 else {
 167                         use_packed_git(p);
 168                         show_pack_info(p);
 169                         unuse_packed_git(p);
 170                         printf("%s: ok\n", p->pack_name);
 171                 }
 172         }
 173
 174         return ret;
 175 }