git/midx.c
Junio C Hamano 567293123d Merge branch 'ps/missing-btmp-fix'
GIt 2.44 introduced a regression that makes the updated code to
barf in repositories with multi-pack index written by older
versions of Git, which has been corrected.

* ps/missing-btmp-fix:
  pack-bitmap: gracefully handle missing BTMP chunks
2024-04-23 11:52:40 -07:00

715 lines
19 KiB
C

#include "git-compat-util.h"
#include "config.h"
#include "dir.h"
#include "hex.h"
#include "packfile.h"
#include "object-file.h"
#include "hash-lookup.h"
#include "midx.h"
#include "progress.h"
#include "trace2.h"
#include "chunk-format.h"
#include "pack-bitmap.h"
#include "pack-revindex.h"
int midx_checksum_valid(struct multi_pack_index *m);
void clear_midx_files_ext(const char *object_dir, const char *ext,
unsigned char *keep_hash);
int cmp_idx_or_pack_name(const char *idx_or_pack_name,
const char *idx_name);
const unsigned char *get_midx_checksum(struct multi_pack_index *m)
{
return m->data + m->data_len - the_hash_algo->rawsz;
}
void get_midx_filename(struct strbuf *out, const char *object_dir)
{
strbuf_addf(out, "%s/pack/multi-pack-index", object_dir);
}
void get_midx_rev_filename(struct strbuf *out, struct multi_pack_index *m)
{
get_midx_filename(out, m->object_dir);
strbuf_addf(out, "-%s.rev", hash_to_hex(get_midx_checksum(m)));
}
static int midx_read_oid_fanout(const unsigned char *chunk_start,
size_t chunk_size, void *data)
{
int i;
struct multi_pack_index *m = data;
m->chunk_oid_fanout = (uint32_t *)chunk_start;
if (chunk_size != 4 * 256) {
error(_("multi-pack-index OID fanout is of the wrong size"));
return 1;
}
for (i = 0; i < 255; i++) {
uint32_t oid_fanout1 = ntohl(m->chunk_oid_fanout[i]);
uint32_t oid_fanout2 = ntohl(m->chunk_oid_fanout[i+1]);
if (oid_fanout1 > oid_fanout2) {
error(_("oid fanout out of order: fanout[%d] = %"PRIx32" > %"PRIx32" = fanout[%d]"),
i, oid_fanout1, oid_fanout2, i + 1);
return 1;
}
}
m->num_objects = ntohl(m->chunk_oid_fanout[255]);
return 0;
}
static int midx_read_oid_lookup(const unsigned char *chunk_start,
size_t chunk_size, void *data)
{
struct multi_pack_index *m = data;
m->chunk_oid_lookup = chunk_start;
if (chunk_size != st_mult(m->hash_len, m->num_objects)) {
error(_("multi-pack-index OID lookup chunk is the wrong size"));
return 1;
}
return 0;
}
static int midx_read_object_offsets(const unsigned char *chunk_start,
size_t chunk_size, void *data)
{
struct multi_pack_index *m = data;
m->chunk_object_offsets = chunk_start;
if (chunk_size != st_mult(m->num_objects, MIDX_CHUNK_OFFSET_WIDTH)) {
error(_("multi-pack-index object offset chunk is the wrong size"));
return 1;
}
return 0;
}
#define MIDX_MIN_SIZE (MIDX_HEADER_SIZE + the_hash_algo->rawsz)
struct multi_pack_index *load_multi_pack_index(const char *object_dir, int local)
{
struct multi_pack_index *m = NULL;
int fd;
struct stat st;
size_t midx_size;
void *midx_map = NULL;
uint32_t hash_version;
struct strbuf midx_name = STRBUF_INIT;
uint32_t i;
const char *cur_pack_name;
struct chunkfile *cf = NULL;
get_midx_filename(&midx_name, object_dir);
fd = git_open(midx_name.buf);
if (fd < 0)
goto cleanup_fail;
if (fstat(fd, &st)) {
error_errno(_("failed to read %s"), midx_name.buf);
goto cleanup_fail;
}
midx_size = xsize_t(st.st_size);
if (midx_size < MIDX_MIN_SIZE) {
error(_("multi-pack-index file %s is too small"), midx_name.buf);
goto cleanup_fail;
}
strbuf_release(&midx_name);
midx_map = xmmap(NULL, midx_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
FLEX_ALLOC_STR(m, object_dir, object_dir);
m->data = midx_map;
m->data_len = midx_size;
m->local = local;
m->signature = get_be32(m->data);
if (m->signature != MIDX_SIGNATURE)
die(_("multi-pack-index signature 0x%08x does not match signature 0x%08x"),
m->signature, MIDX_SIGNATURE);
m->version = m->data[MIDX_BYTE_FILE_VERSION];
if (m->version != MIDX_VERSION)
die(_("multi-pack-index version %d not recognized"),
m->version);
hash_version = m->data[MIDX_BYTE_HASH_VERSION];
if (hash_version != oid_version(the_hash_algo)) {
error(_("multi-pack-index hash version %u does not match version %u"),
hash_version, oid_version(the_hash_algo));
goto cleanup_fail;
}
m->hash_len = the_hash_algo->rawsz;
m->num_chunks = m->data[MIDX_BYTE_NUM_CHUNKS];
m->num_packs = get_be32(m->data + MIDX_BYTE_NUM_PACKS);
m->preferred_pack_idx = -1;
cf = init_chunkfile(NULL);
if (read_table_of_contents(cf, m->data, midx_size,
MIDX_HEADER_SIZE, m->num_chunks,
MIDX_CHUNK_ALIGNMENT))
goto cleanup_fail;
if (pair_chunk(cf, MIDX_CHUNKID_PACKNAMES, &m->chunk_pack_names, &m->chunk_pack_names_len))
die(_("multi-pack-index required pack-name chunk missing or corrupted"));
if (read_chunk(cf, MIDX_CHUNKID_OIDFANOUT, midx_read_oid_fanout, m))
die(_("multi-pack-index required OID fanout chunk missing or corrupted"));
if (read_chunk(cf, MIDX_CHUNKID_OIDLOOKUP, midx_read_oid_lookup, m))
die(_("multi-pack-index required OID lookup chunk missing or corrupted"));
if (read_chunk(cf, MIDX_CHUNKID_OBJECTOFFSETS, midx_read_object_offsets, m))
die(_("multi-pack-index required object offsets chunk missing or corrupted"));
pair_chunk(cf, MIDX_CHUNKID_LARGEOFFSETS, &m->chunk_large_offsets,
&m->chunk_large_offsets_len);
if (git_env_bool("GIT_TEST_MIDX_READ_BTMP", 1))
pair_chunk(cf, MIDX_CHUNKID_BITMAPPEDPACKS,
(const unsigned char **)&m->chunk_bitmapped_packs,
&m->chunk_bitmapped_packs_len);
if (git_env_bool("GIT_TEST_MIDX_READ_RIDX", 1))
pair_chunk(cf, MIDX_CHUNKID_REVINDEX, &m->chunk_revindex,
&m->chunk_revindex_len);
CALLOC_ARRAY(m->pack_names, m->num_packs);
CALLOC_ARRAY(m->packs, m->num_packs);
cur_pack_name = (const char *)m->chunk_pack_names;
for (i = 0; i < m->num_packs; i++) {
const char *end;
size_t avail = m->chunk_pack_names_len -
(cur_pack_name - (const char *)m->chunk_pack_names);
m->pack_names[i] = cur_pack_name;
end = memchr(cur_pack_name, '\0', avail);
if (!end)
die(_("multi-pack-index pack-name chunk is too short"));
cur_pack_name = end + 1;
if (i && strcmp(m->pack_names[i], m->pack_names[i - 1]) <= 0)
die(_("multi-pack-index pack names out of order: '%s' before '%s'"),
m->pack_names[i - 1],
m->pack_names[i]);
}
trace2_data_intmax("midx", the_repository, "load/num_packs", m->num_packs);
trace2_data_intmax("midx", the_repository, "load/num_objects", m->num_objects);
free_chunkfile(cf);
return m;
cleanup_fail:
free(m);
strbuf_release(&midx_name);
free_chunkfile(cf);
if (midx_map)
munmap(midx_map, midx_size);
if (0 <= fd)
close(fd);
return NULL;
}
void close_midx(struct multi_pack_index *m)
{
uint32_t i;
if (!m)
return;
close_midx(m->next);
munmap((unsigned char *)m->data, m->data_len);
for (i = 0; i < m->num_packs; i++) {
if (m->packs[i])
m->packs[i]->multi_pack_index = 0;
}
FREE_AND_NULL(m->packs);
FREE_AND_NULL(m->pack_names);
free(m);
}
int prepare_midx_pack(struct repository *r, struct multi_pack_index *m, uint32_t pack_int_id)
{
struct strbuf pack_name = STRBUF_INIT;
struct packed_git *p;
if (pack_int_id >= m->num_packs)
die(_("bad pack-int-id: %u (%u total packs)"),
pack_int_id, m->num_packs);
if (m->packs[pack_int_id])
return 0;
strbuf_addf(&pack_name, "%s/pack/%s", m->object_dir,
m->pack_names[pack_int_id]);
p = add_packed_git(pack_name.buf, pack_name.len, m->local);
strbuf_release(&pack_name);
if (!p)
return 1;
p->multi_pack_index = 1;
m->packs[pack_int_id] = p;
install_packed_git(r, p);
list_add_tail(&p->mru, &r->objects->packed_git_mru);
return 0;
}
#define MIDX_CHUNK_BITMAPPED_PACKS_WIDTH (2 * sizeof(uint32_t))
int nth_bitmapped_pack(struct repository *r, struct multi_pack_index *m,
struct bitmapped_pack *bp, uint32_t pack_int_id)
{
if (!m->chunk_bitmapped_packs)
return error(_("MIDX does not contain the BTMP chunk"));
if (prepare_midx_pack(r, m, pack_int_id))
return error(_("could not load bitmapped pack %"PRIu32), pack_int_id);
bp->p = m->packs[pack_int_id];
bp->bitmap_pos = get_be32((char *)m->chunk_bitmapped_packs +
MIDX_CHUNK_BITMAPPED_PACKS_WIDTH * pack_int_id);
bp->bitmap_nr = get_be32((char *)m->chunk_bitmapped_packs +
MIDX_CHUNK_BITMAPPED_PACKS_WIDTH * pack_int_id +
sizeof(uint32_t));
bp->pack_int_id = pack_int_id;
return 0;
}
int bsearch_midx(const struct object_id *oid, struct multi_pack_index *m, uint32_t *result)
{
return bsearch_hash(oid->hash, m->chunk_oid_fanout, m->chunk_oid_lookup,
the_hash_algo->rawsz, result);
}
struct object_id *nth_midxed_object_oid(struct object_id *oid,
struct multi_pack_index *m,
uint32_t n)
{
if (n >= m->num_objects)
return NULL;
oidread(oid, m->chunk_oid_lookup + st_mult(m->hash_len, n));
return oid;
}
off_t nth_midxed_offset(struct multi_pack_index *m, uint32_t pos)
{
const unsigned char *offset_data;
uint32_t offset32;
offset_data = m->chunk_object_offsets + (off_t)pos * MIDX_CHUNK_OFFSET_WIDTH;
offset32 = get_be32(offset_data + sizeof(uint32_t));
if (m->chunk_large_offsets && offset32 & MIDX_LARGE_OFFSET_NEEDED) {
if (sizeof(off_t) < sizeof(uint64_t))
die(_("multi-pack-index stores a 64-bit offset, but off_t is too small"));
offset32 ^= MIDX_LARGE_OFFSET_NEEDED;
if (offset32 >= m->chunk_large_offsets_len / sizeof(uint64_t))
die(_("multi-pack-index large offset out of bounds"));
return get_be64(m->chunk_large_offsets + sizeof(uint64_t) * offset32);
}
return offset32;
}
uint32_t nth_midxed_pack_int_id(struct multi_pack_index *m, uint32_t pos)
{
return get_be32(m->chunk_object_offsets +
(off_t)pos * MIDX_CHUNK_OFFSET_WIDTH);
}
int fill_midx_entry(struct repository *r,
const struct object_id *oid,
struct pack_entry *e,
struct multi_pack_index *m)
{
uint32_t pos;
uint32_t pack_int_id;
struct packed_git *p;
if (!bsearch_midx(oid, m, &pos))
return 0;
if (pos >= m->num_objects)
return 0;
pack_int_id = nth_midxed_pack_int_id(m, pos);
if (prepare_midx_pack(r, m, pack_int_id))
return 0;
p = m->packs[pack_int_id];
/*
* We are about to tell the caller where they can locate the
* requested object. We better make sure the packfile is
* still here and can be accessed before supplying that
* answer, as it may have been deleted since the MIDX was
* loaded!
*/
if (!is_pack_valid(p))
return 0;
if (oidset_size(&p->bad_objects) &&
oidset_contains(&p->bad_objects, oid))
return 0;
e->offset = nth_midxed_offset(m, pos);
e->p = p;
return 1;
}
/* Match "foo.idx" against either "foo.pack" _or_ "foo.idx". */
int cmp_idx_or_pack_name(const char *idx_or_pack_name,
const char *idx_name)
{
/* Skip past any initial matching prefix. */
while (*idx_name && *idx_name == *idx_or_pack_name) {
idx_name++;
idx_or_pack_name++;
}
/*
* If we didn't match completely, we may have matched "pack-1234." and
* be left with "idx" and "pack" respectively, which is also OK. We do
* not have to check for "idx" and "idx", because that would have been
* a complete match (and in that case these strcmps will be false, but
* we'll correctly return 0 from the final strcmp() below.
*
* Technically this matches "fooidx" and "foopack", but we'd never have
* such names in the first place.
*/
if (!strcmp(idx_name, "idx") && !strcmp(idx_or_pack_name, "pack"))
return 0;
/*
* This not only checks for a complete match, but also orders based on
* the first non-identical character, which means our ordering will
* match a raw strcmp(). That makes it OK to use this to binary search
* a naively-sorted list.
*/
return strcmp(idx_or_pack_name, idx_name);
}
int midx_locate_pack(struct multi_pack_index *m, const char *idx_or_pack_name,
uint32_t *pos)
{
uint32_t first = 0, last = m->num_packs;
while (first < last) {
uint32_t mid = first + (last - first) / 2;
const char *current;
int cmp;
current = m->pack_names[mid];
cmp = cmp_idx_or_pack_name(idx_or_pack_name, current);
if (!cmp) {
if (pos)
*pos = mid;
return 1;
}
if (cmp > 0) {
first = mid + 1;
continue;
}
last = mid;
}
return 0;
}
int midx_contains_pack(struct multi_pack_index *m, const char *idx_or_pack_name)
{
return midx_locate_pack(m, idx_or_pack_name, NULL);
}
int midx_preferred_pack(struct multi_pack_index *m, uint32_t *pack_int_id)
{
if (m->preferred_pack_idx == -1) {
if (load_midx_revindex(m) < 0) {
m->preferred_pack_idx = -2;
return -1;
}
m->preferred_pack_idx =
nth_midxed_pack_int_id(m, pack_pos_to_midx(m, 0));
} else if (m->preferred_pack_idx == -2)
return -1; /* no revindex */
*pack_int_id = m->preferred_pack_idx;
return 0;
}
int prepare_multi_pack_index_one(struct repository *r, const char *object_dir, int local)
{
struct multi_pack_index *m;
struct multi_pack_index *m_search;
prepare_repo_settings(r);
if (!r->settings.core_multi_pack_index)
return 0;
for (m_search = r->objects->multi_pack_index; m_search; m_search = m_search->next)
if (!strcmp(object_dir, m_search->object_dir))
return 1;
m = load_multi_pack_index(object_dir, local);
if (m) {
struct multi_pack_index *mp = r->objects->multi_pack_index;
if (mp) {
m->next = mp->next;
mp->next = m;
} else
r->objects->multi_pack_index = m;
return 1;
}
return 0;
}
int midx_checksum_valid(struct multi_pack_index *m)
{
return hashfile_checksum_valid(m->data, m->data_len);
}
struct clear_midx_data {
char *keep;
const char *ext;
};
static void clear_midx_file_ext(const char *full_path, size_t full_path_len UNUSED,
const char *file_name, void *_data)
{
struct clear_midx_data *data = _data;
if (!(starts_with(file_name, "multi-pack-index-") &&
ends_with(file_name, data->ext)))
return;
if (data->keep && !strcmp(data->keep, file_name))
return;
if (unlink(full_path))
die_errno(_("failed to remove %s"), full_path);
}
void clear_midx_files_ext(const char *object_dir, const char *ext,
unsigned char *keep_hash)
{
struct clear_midx_data data;
memset(&data, 0, sizeof(struct clear_midx_data));
if (keep_hash)
data.keep = xstrfmt("multi-pack-index-%s%s",
hash_to_hex(keep_hash), ext);
data.ext = ext;
for_each_file_in_pack_dir(object_dir,
clear_midx_file_ext,
&data);
free(data.keep);
}
void clear_midx_file(struct repository *r)
{
struct strbuf midx = STRBUF_INIT;
get_midx_filename(&midx, r->objects->odb->path);
if (r->objects && r->objects->multi_pack_index) {
close_midx(r->objects->multi_pack_index);
r->objects->multi_pack_index = NULL;
}
if (remove_path(midx.buf))
die(_("failed to clear multi-pack-index at %s"), midx.buf);
clear_midx_files_ext(r->objects->odb->path, ".bitmap", NULL);
clear_midx_files_ext(r->objects->odb->path, ".rev", NULL);
strbuf_release(&midx);
}
static int verify_midx_error;
__attribute__((format (printf, 1, 2)))
static void midx_report(const char *fmt, ...)
{
va_list ap;
verify_midx_error = 1;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
fprintf(stderr, "\n");
va_end(ap);
}
struct pair_pos_vs_id
{
uint32_t pos;
uint32_t pack_int_id;
};
static int compare_pair_pos_vs_id(const void *_a, const void *_b)
{
struct pair_pos_vs_id *a = (struct pair_pos_vs_id *)_a;
struct pair_pos_vs_id *b = (struct pair_pos_vs_id *)_b;
return b->pack_int_id - a->pack_int_id;
}
/*
* Limit calls to display_progress() for performance reasons.
* The interval here was arbitrarily chosen.
*/
#define SPARSE_PROGRESS_INTERVAL (1 << 12)
#define midx_display_sparse_progress(progress, n) \
do { \
uint64_t _n = (n); \
if ((_n & (SPARSE_PROGRESS_INTERVAL - 1)) == 0) \
display_progress(progress, _n); \
} while (0)
int verify_midx_file(struct repository *r, const char *object_dir, unsigned flags)
{
struct pair_pos_vs_id *pairs = NULL;
uint32_t i;
struct progress *progress = NULL;
struct multi_pack_index *m = load_multi_pack_index(object_dir, 1);
verify_midx_error = 0;
if (!m) {
int result = 0;
struct stat sb;
struct strbuf filename = STRBUF_INIT;
get_midx_filename(&filename, object_dir);
if (!stat(filename.buf, &sb)) {
error(_("multi-pack-index file exists, but failed to parse"));
result = 1;
}
strbuf_release(&filename);
return result;
}
if (!midx_checksum_valid(m))
midx_report(_("incorrect checksum"));
if (flags & MIDX_PROGRESS)
progress = start_delayed_progress(_("Looking for referenced packfiles"),
m->num_packs);
for (i = 0; i < m->num_packs; i++) {
if (prepare_midx_pack(r, m, i))
midx_report("failed to load pack in position %d", i);
display_progress(progress, i + 1);
}
stop_progress(&progress);
if (m->num_objects == 0) {
midx_report(_("the midx contains no oid"));
/*
* Remaining tests assume that we have objects, so we can
* return here.
*/
goto cleanup;
}
if (flags & MIDX_PROGRESS)
progress = start_sparse_progress(_("Verifying OID order in multi-pack-index"),
m->num_objects - 1);
for (i = 0; i < m->num_objects - 1; i++) {
struct object_id oid1, oid2;
nth_midxed_object_oid(&oid1, m, i);
nth_midxed_object_oid(&oid2, m, i + 1);
if (oidcmp(&oid1, &oid2) >= 0)
midx_report(_("oid lookup out of order: oid[%d] = %s >= %s = oid[%d]"),
i, oid_to_hex(&oid1), oid_to_hex(&oid2), i + 1);
midx_display_sparse_progress(progress, i + 1);
}
stop_progress(&progress);
/*
* Create an array mapping each object to its packfile id. Sort it
* to group the objects by packfile. Use this permutation to visit
* each of the objects and only require 1 packfile to be open at a
* time.
*/
ALLOC_ARRAY(pairs, m->num_objects);
for (i = 0; i < m->num_objects; i++) {
pairs[i].pos = i;
pairs[i].pack_int_id = nth_midxed_pack_int_id(m, i);
}
if (flags & MIDX_PROGRESS)
progress = start_sparse_progress(_("Sorting objects by packfile"),
m->num_objects);
display_progress(progress, 0); /* TODO: Measure QSORT() progress */
QSORT(pairs, m->num_objects, compare_pair_pos_vs_id);
stop_progress(&progress);
if (flags & MIDX_PROGRESS)
progress = start_sparse_progress(_("Verifying object offsets"), m->num_objects);
for (i = 0; i < m->num_objects; i++) {
struct object_id oid;
struct pack_entry e;
off_t m_offset, p_offset;
if (i > 0 && pairs[i-1].pack_int_id != pairs[i].pack_int_id &&
m->packs[pairs[i-1].pack_int_id])
{
close_pack_fd(m->packs[pairs[i-1].pack_int_id]);
close_pack_index(m->packs[pairs[i-1].pack_int_id]);
}
nth_midxed_object_oid(&oid, m, pairs[i].pos);
if (!fill_midx_entry(r, &oid, &e, m)) {
midx_report(_("failed to load pack entry for oid[%d] = %s"),
pairs[i].pos, oid_to_hex(&oid));
continue;
}
if (open_pack_index(e.p)) {
midx_report(_("failed to load pack-index for packfile %s"),
e.p->pack_name);
break;
}
m_offset = e.offset;
p_offset = find_pack_entry_one(oid.hash, e.p);
if (m_offset != p_offset)
midx_report(_("incorrect object offset for oid[%d] = %s: %"PRIx64" != %"PRIx64),
pairs[i].pos, oid_to_hex(&oid), m_offset, p_offset);
midx_display_sparse_progress(progress, i + 1);
}
stop_progress(&progress);
cleanup:
free(pairs);
close_midx(m);
return verify_midx_error;
}