pack-check.con commit show-branch --reflog: add documentation. (abc8ab1)
   1#include "cache.h"
   2#include "pack.h"
   3
   4static int verify_packfile(struct packed_git *p)
   5{
   6        unsigned long index_size = p->index_size;
   7        void *index_base = p->index_base;
   8        SHA_CTX ctx;
   9        unsigned char sha1[20];
  10        unsigned long pack_size = p->pack_size;
  11        void *pack_base;
  12        struct pack_header *hdr;
  13        int nr_objects, err, i;
  14
  15        /* Header consistency check */
  16        hdr = p->pack_base;
  17        if (hdr->hdr_signature != htonl(PACK_SIGNATURE))
  18                return error("Packfile %s signature mismatch", p->pack_name);
  19        if (!pack_version_ok(hdr->hdr_version))
  20                return error("Packfile version %d unsupported",
  21                             ntohl(hdr->hdr_version));
  22        nr_objects = ntohl(hdr->hdr_entries);
  23        if (num_packed_objects(p) != nr_objects)
  24                return error("Packfile claims to have %d objects, "
  25                             "while idx size expects %d", nr_objects,
  26                             num_packed_objects(p));
  27
  28        SHA1_Init(&ctx);
  29        pack_base = p->pack_base;
  30        SHA1_Update(&ctx, pack_base, pack_size - 20);
  31        SHA1_Final(sha1, &ctx);
  32        if (hashcmp(sha1, (unsigned char *)pack_base + pack_size - 20))
  33                return error("Packfile %s SHA1 mismatch with itself",
  34                             p->pack_name);
  35        if (hashcmp(sha1, (unsigned char *)index_base + index_size - 40))
  36                return error("Packfile %s SHA1 mismatch with idx",
  37                             p->pack_name);
  38
  39        /* Make sure everything reachable from idx is valid.  Since we
  40         * have verified that nr_objects matches between idx and pack,
  41         * we do not do scan-streaming check on the pack file.
  42         */
  43        for (i = err = 0; i < nr_objects; i++) {
  44                unsigned char sha1[20];
  45                void *data;
  46                char type[20];
  47                unsigned long size, offset;
  48
  49                if (nth_packed_object_sha1(p, i, sha1))
  50                        die("internal error pack-check nth-packed-object");
  51                offset = find_pack_entry_one(sha1, p);
  52                if (!offset)
  53                        die("internal error pack-check find-pack-entry-one");
  54                data = unpack_entry_gently(p, offset, type, &size);
  55                if (!data) {
  56                        err = error("cannot unpack %s from %s",
  57                                    sha1_to_hex(sha1), p->pack_name);
  58                        continue;
  59                }
  60                if (check_sha1_signature(sha1, data, size, type)) {
  61                        err = error("packed %s from %s is corrupt",
  62                                    sha1_to_hex(sha1), p->pack_name);
  63                        free(data);
  64                        continue;
  65                }
  66                free(data);
  67        }
  68
  69        return err;
  70}
  71
  72
  73#define MAX_CHAIN 40
  74
  75static void show_pack_info(struct packed_git *p)
  76{
  77        struct pack_header *hdr;
  78        int nr_objects, i;
  79        unsigned int chain_histogram[MAX_CHAIN];
  80
  81        hdr = p->pack_base;
  82        nr_objects = ntohl(hdr->hdr_entries);
  83        memset(chain_histogram, 0, sizeof(chain_histogram));
  84
  85        for (i = 0; i < nr_objects; i++) {
  86                unsigned char sha1[20], base_sha1[20];
  87                char type[20];
  88                unsigned long size;
  89                unsigned long store_size;
  90                unsigned long offset;
  91                unsigned int delta_chain_length;
  92
  93                if (nth_packed_object_sha1(p, i, sha1))
  94                        die("internal error pack-check nth-packed-object");
  95                offset = find_pack_entry_one(sha1, p);
  96                if (!offset)
  97                        die("internal error pack-check find-pack-entry-one");
  98
  99                packed_object_info_detail(p, offset, type, &size, &store_size,
 100                                          &delta_chain_length,
 101                                          base_sha1);
 102                printf("%s ", sha1_to_hex(sha1));
 103                if (!delta_chain_length)
 104                        printf("%-6s %lu %lu\n", type, size, offset);
 105                else {
 106                        printf("%-6s %lu %lu %u %s\n", type, size, offset,
 107                               delta_chain_length, sha1_to_hex(base_sha1));
 108                        if (delta_chain_length < MAX_CHAIN)
 109                                chain_histogram[delta_chain_length]++;
 110                        else
 111                                chain_histogram[0]++;
 112                }
 113        }
 114
 115        for (i = 0; i < MAX_CHAIN; i++) {
 116                if (!chain_histogram[i])
 117                        continue;
 118                printf("chain length %s %d: %d object%s\n",
 119                       i ? "=" : ">=",
 120                       i ? i : MAX_CHAIN,
 121                       chain_histogram[i],
 122                       1 < chain_histogram[i] ? "s" : "");
 123        }
 124}
 125
 126int verify_pack(struct packed_git *p, int verbose)
 127{
 128        unsigned long index_size = p->index_size;
 129        void *index_base = p->index_base;
 130        SHA_CTX ctx;
 131        unsigned char sha1[20];
 132        int ret;
 133
 134        ret = 0;
 135        /* Verify SHA1 sum of the index file */
 136        SHA1_Init(&ctx);
 137        SHA1_Update(&ctx, index_base, index_size - 20);
 138        SHA1_Final(sha1, &ctx);
 139        if (hashcmp(sha1, (unsigned char *)index_base + index_size - 20))
 140                ret = error("Packfile index for %s SHA1 mismatch",
 141                            p->pack_name);
 142
 143        if (!ret) {
 144                /* Verify pack file */
 145                use_packed_git(p);
 146                ret = verify_packfile(p);
 147                unuse_packed_git(p);
 148        }
 149
 150        if (verbose) {
 151                if (ret)
 152                        printf("%s: bad\n", p->pack_name);
 153                else {
 154                        use_packed_git(p);
 155                        show_pack_info(p);
 156                        unuse_packed_git(p);
 157                        printf("%s: ok\n", p->pack_name);
 158                }
 159        }
 160
 161        return ret;
 162}