pack-check.c

   1 #include "cache.h"
   2 #include "pack.h"
   3 #include "pack-revindex.h"
   4
   5 struct idx_entry
   6 {
   7         const unsigned char *sha1;
   8         off_t                offset;
   9 };
  10
  11 static int compare_entries(const void *e1, const void *e2)
  12 {
  13         const struct idx_entry *entry1 = e1;
  14         const struct idx_entry *entry2 = e2;
  15         if (entry1->offset < entry2->offset)
  16                 return -1;
  17         if (entry1->offset > entry2->offset)
  18                 return 1;
  19         return 0;
  20 }
  21
  22 static int verify_packfile(struct packed_git *p,
  23                 struct pack_window **w_curs)
  24 {
  25         off_t index_size = p->index_size;
  26         const unsigned char *index_base = p->index_data;
  27         SHA_CTX ctx;
  28         unsigned char sha1[20], *pack_sig;
  29         off_t offset = 0, pack_sig_ofs = p->pack_size - 20;
  30         uint32_t nr_objects, i;
  31         int err = 0;
  32         struct idx_entry *entries;
  33
  34         /* Note that the pack header checks are actually performed by
  35          * use_pack when it first opens the pack file.  If anything
  36          * goes wrong during those checks then the call will die out
  37          * immediately.
  38          */
  39
  40         SHA1_Init(&ctx);
  41         while (offset < pack_sig_ofs) {
  42                 unsigned int remaining;
  43                 unsigned char *in = use_pack(p, w_curs, offset, &remaining);
  44                 offset += remaining;
  45                 if (offset > pack_sig_ofs)
  46                         remaining -= (unsigned int)(offset - pack_sig_ofs);
  47                 SHA1_Update(&ctx, in, remaining);
  48         }
  49         SHA1_Final(sha1, &ctx);
  50         pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
  51         if (hashcmp(sha1, pack_sig))
  52                 err = error("%s SHA1 checksum mismatch",
  53                             p->pack_name);
  54         if (hashcmp(index_base + index_size - 40, pack_sig))
  55                 err = error("%s SHA1 does not match its inddex",
  56                             p->pack_name);
  57         unuse_pack(w_curs);
  58
  59         /* Make sure everything reachable from idx is valid.  Since we
  60          * have verified that nr_objects matches between idx and pack,
  61          * we do not do scan-streaming check on the pack file.
  62          */
  63         nr_objects = p->num_objects;
  64         entries = xmalloc(nr_objects * sizeof(*entries));
  65         /* first sort entries by pack offset, since unpacking them is more efficient that way */
  66         for (i = 0; i < nr_objects; i++) {
  67                 entries[i].sha1 = nth_packed_object_sha1(p, i);
  68                 if (!entries[i].sha1)
  69                         die("internal error pack-check nth-packed-object");
  70                 entries[i].offset = find_pack_entry_one(entries[i].sha1, p);
  71                 if (!entries[i].offset)
  72                         die("internal error pack-check find-pack-entry-one");
  73         }
  74         qsort(entries, nr_objects, sizeof(*entries), compare_entries);
  75
  76         for (i = 0; i < nr_objects; i++) {
  77                 void *data;
  78                 enum object_type type;
  79                 unsigned long size;
  80
  81                 data = unpack_entry(p, entries[i].offset, &type, &size);
  82                 if (!data) {
  83                         err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
  84                                     sha1_to_hex(entries[i].sha1), p->pack_name,
  85                                     (uintmax_t)entries[i].offset);
  86                         break;
  87                 }
  88                 if (check_sha1_signature(entries[i].sha1, data, size, typename(type))) {
  89                         err = error("packed %s from %s is corrupt",
  90                                     sha1_to_hex(entries[i].sha1), p->pack_name);
  91                         free(data);
  92                         break;
  93                 }
  94                 free(data);
  95         }
  96         free(entries);
  97
  98         return err;
  99 }
 100
 101
 102 #define MAX_CHAIN 50
 103
 104 static void show_pack_info(struct packed_git *p)
 105 {
 106         uint32_t nr_objects, i, chain_histogram[MAX_CHAIN+1];
 107
 108         nr_objects = p->num_objects;
 109         memset(chain_histogram, 0, sizeof(chain_histogram));
 110
 111         for (i = 0; i < nr_objects; i++) {
 112                 const unsigned char *sha1;
 113                 unsigned char base_sha1[20];
 114                 const char *type;
 115                 unsigned long size;
 116                 unsigned long store_size;
 117                 off_t offset;
 118                 unsigned int delta_chain_length;
 119
 120                 sha1 = nth_packed_object_sha1(p, i);
 121                 if (!sha1)
 122                         die("internal error pack-check nth-packed-object");
 123                 offset = find_pack_entry_one(sha1, p);
 124                 if (!offset)
 125                         die("internal error pack-check find-pack-entry-one");
 126
 127                 type = packed_object_info_detail(p, offset, &size, &store_size,
 128                                                  &delta_chain_length,
 129                                                  base_sha1);
 130                 printf("%s ", sha1_to_hex(sha1));
 131                 if (!delta_chain_length)
 132                         printf("%-6s %lu %lu %"PRIuMAX"\n",
 133                                type, size, store_size, (uintmax_t)offset);
 134                 else {
 135                         printf("%-6s %lu %lu %"PRIuMAX" %u %s\n",
 136                                type, size, store_size, (uintmax_t)offset,
 137                                delta_chain_length, sha1_to_hex(base_sha1));
 138                         if (delta_chain_length <= MAX_CHAIN)
 139                                 chain_histogram[delta_chain_length]++;
 140                         else
 141                                 chain_histogram[0]++;
 142                 }
 143         }
 144
 145         for (i = 0; i <= MAX_CHAIN; i++) {
 146                 if (!chain_histogram[i])
 147                         continue;
 148                 printf("chain length = %d: %d object%s\n", i,
 149                        chain_histogram[i], chain_histogram[i] > 1 ? "s" : "");
 150         }
 151         if (chain_histogram[0])
 152                 printf("chain length > %d: %d object%s\n", MAX_CHAIN,
 153                        chain_histogram[0], chain_histogram[0] > 1 ? "s" : "");
 154 }
 155
 156 int verify_pack(struct packed_git *p, int verbose)
 157 {
 158         off_t index_size;
 159         const unsigned char *index_base;
 160         SHA_CTX ctx;
 161         unsigned char sha1[20];
 162         int err = 0;
 163         struct pack_window *w_curs = NULL;
 164
 165         if (open_pack_index(p))
 166                 return error("packfile %s index not opened", p->pack_name);
 167         index_size = p->index_size;
 168         index_base = p->index_data;
 169
 170         /* Verify SHA1 sum of the index file */
 171         SHA1_Init(&ctx);
 172         SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
 173         SHA1_Final(sha1, &ctx);
 174         if (hashcmp(sha1, index_base + index_size - 20))
 175                 err = error("Packfile index for %s SHA1 mismatch",
 176                             p->pack_name);
 177
 178         /* Verify pack file */
 179         err |= verify_packfile(p, &w_curs);
 180         unuse_pack(&w_curs);
 181
 182         if (verbose) {
 183                 if (err)
 184                         printf("%s: bad\n", p->pack_name);
 185                 else {
 186                         show_pack_info(p);
 187                         printf("%s: ok\n", p->pack_name);
 188                 }
 189         }
 190
 191         return err;
 192 }