Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "pack.h"
   3#include "pack-revindex.h"
   4#include "progress.h"
   5
   6struct idx_entry {
   7        off_t                offset;
   8        const unsigned char *sha1;
   9        unsigned int nr;
  10};
  11
  12static int compare_entries(const void *e1, const void *e2)
  13{
  14        const struct idx_entry *entry1 = e1;
  15        const struct idx_entry *entry2 = e2;
  16        if (entry1->offset < entry2->offset)
  17                return -1;
  18        if (entry1->offset > entry2->offset)
  19                return 1;
  20        return 0;
  21}
  22
  23int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
  24                   off_t offset, off_t len, unsigned int nr)
  25{
  26        const uint32_t *index_crc;
  27        uint32_t data_crc = crc32(0, NULL, 0);
  28
  29        do {
  30                unsigned long avail;
  31                void *data = use_pack(p, w_curs, offset, &avail);
  32                if (avail > len)
  33                        avail = len;
  34                data_crc = crc32(data_crc, data, avail);
  35                offset += avail;
  36                len -= avail;
  37        } while (len);
  38
  39        index_crc = p->index_data;
  40        index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
  41
  42        return data_crc != ntohl(*index_crc);
  43}
  44
  45static int verify_packfile(struct packed_git *p,
  46                           struct pack_window **w_curs,
  47                           verify_fn fn,
  48                           struct progress *progress, uint32_t base_count)
  49
  50{
  51        off_t index_size = p->index_size;
  52        const unsigned char *index_base = p->index_data;
  53        git_SHA_CTX ctx;
  54        unsigned char sha1[20], *pack_sig;
  55        off_t offset = 0, pack_sig_ofs = 0;
  56        uint32_t nr_objects, i;
  57        int err = 0;
  58        struct idx_entry *entries;
  59
  60        /* Note that the pack header checks are actually performed by
  61         * use_pack when it first opens the pack file.  If anything
  62         * goes wrong during those checks then the call will die out
  63         * immediately.
  64         */
  65
  66        git_SHA1_Init(&ctx);
  67        do {
  68                unsigned long remaining;
  69                unsigned char *in = use_pack(p, w_curs, offset, &remaining);
  70                offset += remaining;
  71                if (!pack_sig_ofs)
  72                        pack_sig_ofs = p->pack_size - 20;
  73                if (offset > pack_sig_ofs)
  74                        remaining -= (unsigned int)(offset - pack_sig_ofs);
  75                git_SHA1_Update(&ctx, in, remaining);
  76        } while (offset < pack_sig_ofs);
  77        git_SHA1_Final(sha1, &ctx);
  78        pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
  79        if (hashcmp(sha1, pack_sig))
  80                err = error("%s SHA1 checksum mismatch",
  81                            p->pack_name);
  82        if (hashcmp(index_base + index_size - 40, pack_sig))
  83                err = error("%s SHA1 does not match its index",
  84                            p->pack_name);
  85        unuse_pack(w_curs);
  86
  87        /* Make sure everything reachable from idx is valid.  Since we
  88         * have verified that nr_objects matches between idx and pack,
  89         * we do not do scan-streaming check on the pack file.
  90         */
  91        nr_objects = p->num_objects;
  92        entries = xmalloc((nr_objects + 1) * sizeof(*entries));
  93        entries[nr_objects].offset = pack_sig_ofs;
  94        /* first sort entries by pack offset, since unpacking them is more efficient that way */
  95        for (i = 0; i < nr_objects; i++) {
  96                entries[i].sha1 = nth_packed_object_sha1(p, i);
  97                if (!entries[i].sha1)
  98                        die("internal error pack-check nth-packed-object");
  99                entries[i].offset = nth_packed_object_offset(p, i);
 100                entries[i].nr = i;
 101        }
 102        qsort(entries, nr_objects, sizeof(*entries), compare_entries);
 103
 104        for (i = 0; i < nr_objects; i++) {
 105                void *data;
 106                enum object_type type;
 107                unsigned long size;
 108
 109                if (p->index_version > 1) {
 110                        off_t offset = entries[i].offset;
 111                        off_t len = entries[i+1].offset - offset;
 112                        unsigned int nr = entries[i].nr;
 113                        if (check_pack_crc(p, w_curs, offset, len, nr))
 114                                err = error("index CRC mismatch for object %s "
 115                                            "from %s at offset %"PRIuMAX"",
 116                                            sha1_to_hex(entries[i].sha1),
 117                                            p->pack_name, (uintmax_t)offset);
 118                }
 119                data = unpack_entry(p, entries[i].offset, &type, &size);
 120                if (!data)
 121                        err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
 122                                    sha1_to_hex(entries[i].sha1), p->pack_name,
 123                                    (uintmax_t)entries[i].offset);
 124                else if (check_sha1_signature(entries[i].sha1, data, size, typename(type)))
 125                        err = error("packed %s from %s is corrupt",
 126                                    sha1_to_hex(entries[i].sha1), p->pack_name);
 127                else if (fn) {
 128                        int eaten = 0;
 129                        err |= fn(entries[i].sha1, type, size, data, &eaten);
 130                        if (eaten)
 131                                data = NULL;
 132                }
 133                if (((base_count + i) & 1023) == 0)
 134                        display_progress(progress, base_count + i);
 135                free(data);
 136
 137        }
 138        display_progress(progress, base_count + i);
 139        free(entries);
 140
 141        return err;
 142}
 143
 144int verify_pack_index(struct packed_git *p)
 145{
 146        off_t index_size;
 147        const unsigned char *index_base;
 148        git_SHA_CTX ctx;
 149        unsigned char sha1[20];
 150        int err = 0;
 151
 152        if (open_pack_index(p))
 153                return error("packfile %s index not opened", p->pack_name);
 154        index_size = p->index_size;
 155        index_base = p->index_data;
 156
 157        /* Verify SHA1 sum of the index file */
 158        git_SHA1_Init(&ctx);
 159        git_SHA1_Update(&ctx, index_base, (unsigned int)(index_size - 20));
 160        git_SHA1_Final(sha1, &ctx);
 161        if (hashcmp(sha1, index_base + index_size - 20))
 162                err = error("Packfile index for %s SHA1 mismatch",
 163                            p->pack_name);
 164        return err;
 165}
 166
 167int verify_pack(struct packed_git *p, verify_fn fn,
 168                struct progress *progress, uint32_t base_count)
 169{
 170        int err = 0;
 171        struct pack_window *w_curs = NULL;
 172
 173        err |= verify_pack_index(p);
 174        if (!p->index_data)
 175                return -1;
 176
 177        err |= verify_packfile(p, &w_curs, fn, progress, base_count);
 178        unuse_pack(&w_curs);
 179
 180        return err;
 181}