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git-mirror/cache-tree.c
Jeff King c4c9089584 cache-tree: avoid strtol() on non-string buffer 
A cache-tree extension entry in the index looks like this:

  <name> NUL <entry_nr> SPACE <subtree_nr> NEWLINE <binary_oid>

where the "_nr" items are human-readable base-10 ASCII. We parse them
with strtol(), even though we do not have a NUL-terminated string (we'd
generally have an mmap() of the on-disk index file). For a well-formed
entry, this is not a problem; strtol() will stop when it sees the
newline. But there are two problems:

  1. A corrupted entry could omit the newline, causing us to read
     further. You'd mostly get stopped by seeing non-digits in the oid
     field (and if it is likewise truncated, there will still be 20 or
     more bytes of the index checksum). So it's possible, though
     unlikely, to read off the end of the mmap'd buffer. Of course a
     malicious index file can fake the oid and the index checksum to all
     (ASCII) 0's.

     This is further complicated by the fact that mmap'd buffers tend to
     be zero-padded up to the page boundary. So to run off the end, the
     index size also has to be a multiple of the page size. This is also
     unlikely, though you can construct a malicious index file that
     matches this.

     The security implications aren't too interesting. The index file is
     a local file anyway (so you can't attack somebody by cloning, but
     only if you convince them to operate in a .git directory you made,
     at which point attacking .git/config is much easier). And it's just
     a read overflow via strtol(), which is unlikely to buy you much
     beyond a crash.

  2. ASan has a strict_string_checks option, which tells it to make sure
     that options to string functions (like strtol) have some eventual
     NUL, without regard to what the function would actually do (like
     stopping at a newline here). This option sometimes has false
     positives, but it can point to sketchy areas (like this one) where
     the input we use doesn't exhibit a problem, but different input
     _could_ cause us to misbehave.

Let's fix it by just parsing the values ourselves with a helper function
that is careful not to go past the end of the buffer. There are a few
behavior changes here that should not matter:

  - We do not consider overflow, as strtol() would. But nor did the
    original code. However, we don't trust the value we get from the
    on-disk file, and if it says to read 2^30 entries, we would notice
    that we do not have that many and bail before reading off the end of
    the buffer.

  - Our helper does not skip past extra leading whitespace as strtol()
    would, but according to gitformat-index(5) there should not be any.

  - The original quit parsing at a newline or a NUL byte, but now we
    insist on a newline (which is what the documentation says, and what
    Git has always produced).

Since we are providing our own helper function, we can tweak the
interface a bit to make our lives easier. The original code does not use
strtol's "end" pointer to find the end of the parsed data, but rather
uses a separate loop to advance our "buf" pointer to the trailing
newline. We can instead provide a helper that advances "buf" as it
parses, letting us read strictly left-to-right through the buffer.

I didn't add a new test here. It's surprisingly difficult to construct
an index of exactly the right size due to the way we pad entries. But it
is easy to trigger the problem in existing tests when using ASan's
strict string checking, coupled with a recent change to use NO_MMAP with
ASan builds. So:

  make SANITIZE=address
  cd t
  ASAN_OPTIONS=strict_string_checks=1 ./t0090-cache-tree.sh

triggers it reliably. Technically it is not deterministic because there
is ~8% chance (it's 1-(255/256)^20, or ^32 for sha256) that the trailing
checksum hash has a NUL byte in it. But we compute enough cache-trees in
the course of that script that we are very likely to hit the problem in
one of them.

We can look at making strict_string_checks the default for ASan builds,
but there are some other cases we'd want to fix first.

Reported-by: correctmost <cmlists@sent.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-18 09:36:06 -08:00

1058 lines
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#define USE_THE_REPOSITORY_VARIABLE
#define DISABLE_SIGN_COMPARE_WARNINGS
#include "git-compat-util.h"
#include "gettext.h"
#include "hex.h"
#include "lockfile.h"
#include "tree.h"
#include "tree-walk.h"
#include "cache-tree.h"
#include "bulk-checkin.h"
#include "object-file.h"
#include "object-store.h"
#include "read-cache-ll.h"
#include "replace-object.h"
#include "repository.h"
#include "promisor-remote.h"
#include "trace.h"
#include "trace2.h"
#ifndef DEBUG_CACHE_TREE
#define DEBUG_CACHE_TREE 0
#endif
struct cache_tree *cache_tree(void)
{
struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
it->entry_count = -1;
return it;
}
void cache_tree_free(struct cache_tree **it_p)
{
int i;
struct cache_tree *it = *it_p;
if (!it)
return;
for (i = 0; i < it->subtree_nr; i++)
if (it->down[i]) {
cache_tree_free(&it->down[i]->cache_tree);
free(it->down[i]);
}
free(it->down);
free(it);
*it_p = NULL;
}
static int subtree_name_cmp(const char *one, int onelen,
const char *two, int twolen)
{
if (onelen < twolen)
return -1;
if (twolen < onelen)
return 1;
return memcmp(one, two, onelen);
}
int cache_tree_subtree_pos(struct cache_tree *it, const char *path, int pathlen)
{
struct cache_tree_sub **down = it->down;
int lo, hi;
lo = 0;
hi = it->subtree_nr;
while (lo < hi) {
int mi = lo + (hi - lo) / 2;
struct cache_tree_sub *mdl = down[mi];
int cmp = subtree_name_cmp(path, pathlen,
mdl->name, mdl->namelen);
if (!cmp)
return mi;
if (cmp < 0)
hi = mi;
else
lo = mi + 1;
}
return -lo-1;
}
static struct cache_tree_sub *find_subtree(struct cache_tree *it,
const char *path,
int pathlen,
int create)
{
struct cache_tree_sub *down;
int pos = cache_tree_subtree_pos(it, path, pathlen);
if (0 <= pos)
return it->down[pos];
if (!create)
return NULL;
pos = -pos-1;
ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
it->subtree_nr++;
FLEX_ALLOC_MEM(down, name, path, pathlen);
down->cache_tree = NULL;
down->namelen = pathlen;
if (pos < it->subtree_nr)
MOVE_ARRAY(it->down + pos + 1, it->down + pos,
it->subtree_nr - pos - 1);
it->down[pos] = down;
return down;
}
struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
{
int pathlen = strlen(path);
return find_subtree(it, path, pathlen, 1);
}
static int do_invalidate_path(struct cache_tree *it, const char *path)
{
/* a/b/c
* ==> invalidate self
* ==> find "a", have it invalidate "b/c"
* a
* ==> invalidate self
* ==> if "a" exists as a subtree, remove it.
*/
const char *slash;
int namelen;
struct cache_tree_sub *down;
#if DEBUG_CACHE_TREE
fprintf(stderr, "cache-tree invalidate <%s>\n", path);
#endif
if (!it)
return 0;
slash = strchrnul(path, '/');
namelen = slash - path;
it->entry_count = -1;
if (!*slash) {
int pos;
pos = cache_tree_subtree_pos(it, path, namelen);
if (0 <= pos) {
cache_tree_free(&it->down[pos]->cache_tree);
free(it->down[pos]);
/* 0 1 2 3 4 5
* ^ ^subtree_nr = 6
* pos
* move 4 and 5 up one place (2 entries)
* 2 = 6 - 3 - 1 = subtree_nr - pos - 1
*/
MOVE_ARRAY(it->down + pos, it->down + pos + 1,
it->subtree_nr - pos - 1);
it->subtree_nr--;
}
return 1;
}
down = find_subtree(it, path, namelen, 0);
if (down)
do_invalidate_path(down->cache_tree, slash + 1);
return 1;
}
void cache_tree_invalidate_path(struct index_state *istate, const char *path)
{
if (do_invalidate_path(istate->cache_tree, path))
istate->cache_changed |= CACHE_TREE_CHANGED;
}
static int verify_cache(struct index_state *istate, int flags)
{
unsigned i, funny;
int silent = flags & WRITE_TREE_SILENT;
/* Verify that the tree is merged */
funny = 0;
for (i = 0; i < istate->cache_nr; i++) {
const struct cache_entry *ce = istate->cache[i];
if (ce_stage(ce)) {
if (silent)
return -1;
if (10 < ++funny) {
fprintf(stderr, "...\n");
break;
}
fprintf(stderr, "%s: unmerged (%s)\n",
ce->name, oid_to_hex(&ce->oid));
}
}
if (funny)
return -1;
/* Also verify that the cache does not have path and path/file
* at the same time. At this point we know the cache has only
* stage 0 entries.
*/
funny = 0;
for (i = 0; i + 1 < istate->cache_nr; i++) {
/* path/file always comes after path because of the way
* the cache is sorted. Also path can appear only once,
* which means conflicting one would immediately follow.
*/
const struct cache_entry *this_ce = istate->cache[i];
const struct cache_entry *next_ce = istate->cache[i + 1];
const char *this_name = this_ce->name;
const char *next_name = next_ce->name;
int this_len = ce_namelen(this_ce);
if (this_len < ce_namelen(next_ce) &&
next_name[this_len] == '/' &&
strncmp(this_name, next_name, this_len) == 0) {
if (10 < ++funny) {
fprintf(stderr, "...\n");
break;
}
fprintf(stderr, "You have both %s and %s\n",
this_name, next_name);
}
}
if (funny)
return -1;
return 0;
}
static void discard_unused_subtrees(struct cache_tree *it)
{
struct cache_tree_sub **down = it->down;
int nr = it->subtree_nr;
int dst, src;
for (dst = src = 0; src < nr; src++) {
struct cache_tree_sub *s = down[src];
if (s->used)
down[dst++] = s;
else {
cache_tree_free(&s->cache_tree);
free(s);
it->subtree_nr--;
}
}
}
int cache_tree_fully_valid(struct cache_tree *it)
{
int i;
if (!it)
return 0;
if (it->entry_count < 0 ||
has_object(the_repository, &it->oid,
HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR))
return 0;
for (i = 0; i < it->subtree_nr; i++) {
if (!cache_tree_fully_valid(it->down[i]->cache_tree))
return 0;
}
return 1;
}
static int must_check_existence(const struct cache_entry *ce)
{
return !(repo_has_promisor_remote(the_repository) && ce_skip_worktree(ce));
}
static int update_one(struct cache_tree *it,
struct cache_entry **cache,
int entries,
const char *base,
int baselen,
int *skip_count,
int flags)
{
struct strbuf buffer;
int missing_ok = flags & WRITE_TREE_MISSING_OK;
int dryrun = flags & WRITE_TREE_DRY_RUN;
int repair = flags & WRITE_TREE_REPAIR;
int to_invalidate = 0;
int i;
assert(!(dryrun && repair));
*skip_count = 0;
/*
* If the first entry of this region is a sparse directory
* entry corresponding exactly to 'base', then this cache_tree
* struct is a "leaf" in the data structure, pointing to the
* tree OID specified in the entry.
*/
if (entries > 0) {
const struct cache_entry *ce = cache[0];
if (S_ISSPARSEDIR(ce->ce_mode) &&
ce->ce_namelen == baselen &&
!strncmp(ce->name, base, baselen)) {
it->entry_count = 1;
oidcpy(&it->oid, &ce->oid);
return 1;
}
}
if (0 <= it->entry_count &&
has_object(the_repository, &it->oid,
HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR))
return it->entry_count;
/*
* We first scan for subtrees and update them; we start by
* marking existing subtrees -- the ones that are unmarked
* should not be in the result.
*/
for (i = 0; i < it->subtree_nr; i++)
it->down[i]->used = 0;
/*
* Find the subtrees and update them.
*/
i = 0;
while (i < entries) {
const struct cache_entry *ce = cache[i];
struct cache_tree_sub *sub;
const char *path, *slash;
int pathlen, sublen, subcnt, subskip;
path = ce->name;
pathlen = ce_namelen(ce);
if (pathlen <= baselen || memcmp(base, path, baselen))
break; /* at the end of this level */
slash = strchr(path + baselen, '/');
if (!slash) {
i++;
continue;
}
/*
* a/bbb/c (base = a/, slash = /c)
* ==>
* path+baselen = bbb/c, sublen = 3
*/
sublen = slash - (path + baselen);
sub = find_subtree(it, path + baselen, sublen, 1);
if (!sub->cache_tree)
sub->cache_tree = cache_tree();
subcnt = update_one(sub->cache_tree,
cache + i, entries - i,
path,
baselen + sublen + 1,
&subskip,
flags);
if (subcnt < 0)
return subcnt;
if (!subcnt)
die("index cache-tree records empty sub-tree");
i += subcnt;
sub->count = subcnt; /* to be used in the next loop */
*skip_count += subskip;
sub->used = 1;
}
discard_unused_subtrees(it);
/*
* Then write out the tree object for this level.
*/
strbuf_init(&buffer, 8192);
i = 0;
while (i < entries) {
const struct cache_entry *ce = cache[i];
struct cache_tree_sub *sub = NULL;
const char *path, *slash;
int pathlen, entlen;
const struct object_id *oid;
unsigned mode;
int expected_missing = 0;
int contains_ita = 0;
int ce_missing_ok;
path = ce->name;
pathlen = ce_namelen(ce);
if (pathlen <= baselen || memcmp(base, path, baselen))
break; /* at the end of this level */
slash = strchr(path + baselen, '/');
if (slash) {
entlen = slash - (path + baselen);
sub = find_subtree(it, path + baselen, entlen, 0);
if (!sub)
die("cache-tree.c: '%.*s' in '%s' not found",
entlen, path + baselen, path);
i += sub->count;
oid = &sub->cache_tree->oid;
mode = S_IFDIR;
contains_ita = sub->cache_tree->entry_count < 0;
if (contains_ita) {
to_invalidate = 1;
expected_missing = 1;
}
}
else {
oid = &ce->oid;
mode = ce->ce_mode;
entlen = pathlen - baselen;
i++;
}
ce_missing_ok = mode == S_IFGITLINK || missing_ok ||
!must_check_existence(ce);
if (is_null_oid(oid) ||
(!ce_missing_ok && !has_object(the_repository, oid,
HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR))) {
strbuf_release(&buffer);
if (expected_missing)
return -1;
return error("invalid object %06o %s for '%.*s'",
mode, oid_to_hex(oid), entlen+baselen, path);
}
/*
* CE_REMOVE entries are removed before the index is
* written to disk. Skip them to remain consistent
* with the future on-disk index.
*/
if (ce->ce_flags & CE_REMOVE) {
*skip_count = *skip_count + 1;
continue;
}
/*
* CE_INTENT_TO_ADD entries exist in on-disk index but
* they are not part of generated trees. Invalidate up
* to root to force cache-tree users to read elsewhere.
*/
if (!sub && ce_intent_to_add(ce)) {
to_invalidate = 1;
continue;
}
/*
* "sub" can be an empty tree if all subentries are i-t-a.
*/
if (contains_ita && is_empty_tree_oid(oid, the_repository->hash_algo))
continue;
strbuf_grow(&buffer, entlen + 100);
strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
#if DEBUG_CACHE_TREE
fprintf(stderr, "cache-tree update-one %o %.*s\n",
mode, entlen, path + baselen);
#endif
}
if (repair) {
struct object_id oid;
hash_object_file(the_hash_algo, buffer.buf, buffer.len,
OBJ_TREE, &oid);
if (has_object(the_repository, &oid, HAS_OBJECT_RECHECK_PACKED))
oidcpy(&it->oid, &oid);
else
to_invalidate = 1;
} else if (dryrun) {
hash_object_file(the_hash_algo, buffer.buf, buffer.len,
OBJ_TREE, &it->oid);
} else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
&it->oid, NULL, flags & WRITE_TREE_SILENT
? WRITE_OBJECT_FILE_SILENT : 0)) {
strbuf_release(&buffer);
return -1;
}
strbuf_release(&buffer);
it->entry_count = to_invalidate ? -1 : i - *skip_count;
#if DEBUG_CACHE_TREE
fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
it->entry_count, it->subtree_nr,
oid_to_hex(&it->oid));
#endif
return i;
}
int cache_tree_update(struct index_state *istate, int flags)
{
int skip, i;
i = verify_cache(istate, flags);
if (i)
return i;
if (!istate->cache_tree)
istate->cache_tree = cache_tree();
if (!(flags & WRITE_TREE_MISSING_OK) && repo_has_promisor_remote(the_repository))
prefetch_cache_entries(istate, must_check_existence);
trace_performance_enter();
trace2_region_enter("cache_tree", "update", the_repository);
begin_odb_transaction();
i = update_one(istate->cache_tree, istate->cache, istate->cache_nr,
"", 0, &skip, flags);
end_odb_transaction();
trace2_region_leave("cache_tree", "update", the_repository);
trace_performance_leave("cache_tree_update");
if (i < 0)
return i;
istate->cache_changed |= CACHE_TREE_CHANGED;
return 0;
}
static void write_one(struct strbuf *buffer, struct cache_tree *it,
const char *path, int pathlen)
{
int i;
/* One "cache-tree" entry consists of the following:
* path (NUL terminated)
* entry_count, subtree_nr ("%d %d\n")
* tree-sha1 (missing if invalid)
* subtree_nr "cache-tree" entries for subtrees.
*/
strbuf_grow(buffer, pathlen + 100);
strbuf_add(buffer, path, pathlen);
strbuf_addf(buffer, "%c%d %d\n", 0, it->entry_count, it->subtree_nr);
#if DEBUG_CACHE_TREE
if (0 <= it->entry_count)
fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
pathlen, path, it->entry_count, it->subtree_nr,
oid_to_hex(&it->oid));
else
fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
pathlen, path, it->subtree_nr);
#endif
if (0 <= it->entry_count) {
strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
}
for (i = 0; i < it->subtree_nr; i++) {
struct cache_tree_sub *down = it->down[i];
if (i) {
struct cache_tree_sub *prev = it->down[i-1];
if (subtree_name_cmp(down->name, down->namelen,
prev->name, prev->namelen) <= 0)
die("fatal - unsorted cache subtree");
}
write_one(buffer, down->cache_tree, down->name, down->namelen);
}
}
void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
{
trace2_region_enter("cache_tree", "write", the_repository);
write_one(sb, root, "", 0);
trace2_region_leave("cache_tree", "write", the_repository);
}
static int parse_int(const char **ptr, unsigned long *len_p, int *out)
{
const char *s = *ptr;
unsigned long len = *len_p;
int ret = 0;
int sign = 1;
while (len && *s == '-') {
sign *= -1;
s++;
len--;
}
while (len) {
if (!isdigit(*s))
break;
ret *= 10;
ret += *s - '0';
s++;
len--;
}
if (s == *ptr)
return -1;
*ptr = s;
*len_p = len;
*out = sign * ret;
return 0;
}
static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
{
const char *buf = *buffer;
unsigned long size = *size_p;
struct cache_tree *it;
int i, subtree_nr;
const unsigned rawsz = the_hash_algo->rawsz;
it = NULL;
/* skip name, but make sure name exists */
while (size && *buf) {
size--;
buf++;
}
if (!size)
goto free_return;
buf++; size--;
it = cache_tree();
if (parse_int(&buf, &size, &it->entry_count) < 0)
goto free_return;
if (!size || *buf != ' ')
goto free_return;
buf++; size--;
if (parse_int(&buf, &size, &subtree_nr) < 0)
goto free_return;
if (!size || *buf != '\n')
goto free_return;
buf++; size--;
if (0 <= it->entry_count) {
if (size < rawsz)
goto free_return;
oidread(&it->oid, (const unsigned char *)buf,
the_repository->hash_algo);
buf += rawsz;
size -= rawsz;
}
#if DEBUG_CACHE_TREE
if (0 <= it->entry_count)
fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
*buffer, it->entry_count, subtree_nr,
oid_to_hex(&it->oid));
else
fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
*buffer, subtree_nr);
#endif
/*
* Just a heuristic -- we do not add directories that often but
* we do not want to have to extend it immediately when we do,
* hence +2.
*/
it->subtree_alloc = subtree_nr + 2;
CALLOC_ARRAY(it->down, it->subtree_alloc);
for (i = 0; i < subtree_nr; i++) {
/* read each subtree */
struct cache_tree *sub;
struct cache_tree_sub *subtree;
const char *name = buf;
sub = read_one(&buf, &size);
if (!sub)
goto free_return;
subtree = cache_tree_sub(it, name);
subtree->cache_tree = sub;
}
if (subtree_nr != it->subtree_nr)
die("cache-tree: internal error");
*buffer = buf;
*size_p = size;
return it;
free_return:
cache_tree_free(&it);
return NULL;
}
struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
{
struct cache_tree *result;
if (buffer[0])
return NULL; /* not the whole tree */
trace2_region_enter("cache_tree", "read", the_repository);
result = read_one(&buffer, &size);
trace2_region_leave("cache_tree", "read", the_repository);
return result;
}
static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
{
if (!it)
return NULL;
while (*path) {
const char *slash;
struct cache_tree_sub *sub;
slash = strchrnul(path, '/');
/*
* Between path and slash is the name of the subtree
* to look for.
*/
sub = find_subtree(it, path, slash - path, 0);
if (!sub)
return NULL;
it = sub->cache_tree;
path = slash;
while (*path == '/')
path++;
}
return it;
}
static int write_index_as_tree_internal(struct object_id *oid,
struct index_state *index_state,
int cache_tree_valid,
int flags,
const char *prefix)
{
if (flags & WRITE_TREE_IGNORE_CACHE_TREE) {
cache_tree_free(&index_state->cache_tree);
cache_tree_valid = 0;
}
if (!cache_tree_valid && cache_tree_update(index_state, flags) < 0)
return WRITE_TREE_UNMERGED_INDEX;
if (prefix) {
struct cache_tree *subtree;
subtree = cache_tree_find(index_state->cache_tree, prefix);
if (!subtree)
return WRITE_TREE_PREFIX_ERROR;
oidcpy(oid, &subtree->oid);
}
else
oidcpy(oid, &index_state->cache_tree->oid);
return 0;
}
struct tree* write_in_core_index_as_tree(struct repository *repo) {
struct object_id o;
int was_valid, ret;
struct index_state *index_state = repo->index;
was_valid = index_state->cache_tree &&
cache_tree_fully_valid(index_state->cache_tree);
ret = write_index_as_tree_internal(&o, index_state, was_valid, 0, NULL);
if (ret == WRITE_TREE_UNMERGED_INDEX) {
int i;
bug("there are unmerged index entries:");
for (i = 0; i < index_state->cache_nr; i++) {
const struct cache_entry *ce = index_state->cache[i];
if (ce_stage(ce))
bug("%d %.*s", ce_stage(ce),
(int)ce_namelen(ce), ce->name);
}
BUG("unmerged index entries when writing in-core index");
}
return lookup_tree(repo, &index_state->cache_tree->oid);
}
int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
{
int entries, was_valid;
struct lock_file lock_file = LOCK_INIT;
int ret;
hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
entries = read_index_from(index_state, index_path,
repo_get_git_dir(the_repository));
if (entries < 0) {
ret = WRITE_TREE_UNREADABLE_INDEX;
goto out;
}
was_valid = !(flags & WRITE_TREE_IGNORE_CACHE_TREE) &&
index_state->cache_tree &&
cache_tree_fully_valid(index_state->cache_tree);
ret = write_index_as_tree_internal(oid, index_state, was_valid, flags,
prefix);
if (!ret && !was_valid) {
write_locked_index(index_state, &lock_file, COMMIT_LOCK);
/* Not being able to write is fine -- we are only interested
* in updating the cache-tree part, and if the next caller
* ends up using the old index with unupdated cache-tree part
* it misses the work we did here, but that is just a
* performance penalty and not a big deal.
*/
}
out:
rollback_lock_file(&lock_file);
return ret;
}
static void prime_cache_tree_sparse_dir(struct cache_tree *it,
struct tree *tree)
{
oidcpy(&it->oid, &tree->object.oid);
it->entry_count = 1;
}
static void prime_cache_tree_rec(struct repository *r,
struct cache_tree *it,
struct tree *tree,
struct strbuf *tree_path)
{
struct tree_desc desc;
struct name_entry entry;
int cnt;
size_t base_path_len = tree_path->len;
oidcpy(&it->oid, &tree->object.oid);
init_tree_desc(&desc, &tree->object.oid, tree->buffer, tree->size);
cnt = 0;
while (tree_entry(&desc, &entry)) {
if (!S_ISDIR(entry.mode))
cnt++;
else {
struct cache_tree_sub *sub;
struct tree *subtree = lookup_tree(r, &entry.oid);
if (parse_tree(subtree) < 0)
exit(128);
sub = cache_tree_sub(it, entry.path);
sub->cache_tree = cache_tree();
/*
* Recursively-constructed subtree path is only needed when working
* in a sparse index (where it's used to determine whether the
* subtree is a sparse directory in the index).
*/
if (r->index->sparse_index) {
strbuf_setlen(tree_path, base_path_len);
strbuf_add(tree_path, entry.path, entry.pathlen);
strbuf_addch(tree_path, '/');
}
/*
* If a sparse index is in use, the directory being processed may be
* sparse. To confirm that, we can check whether an entry with that
* exact name exists in the index. If it does, the created subtree
* should be sparse. Otherwise, cache tree expansion should continue
* as normal.
*/
if (r->index->sparse_index &&
index_entry_exists(r->index, tree_path->buf, tree_path->len))
prime_cache_tree_sparse_dir(sub->cache_tree, subtree);
else
prime_cache_tree_rec(r, sub->cache_tree, subtree, tree_path);
cnt += sub->cache_tree->entry_count;
}
}
it->entry_count = cnt;
}
void prime_cache_tree(struct repository *r,
struct index_state *istate,
struct tree *tree)
{
struct strbuf tree_path = STRBUF_INIT;
trace2_region_enter("cache-tree", "prime_cache_tree", r);
cache_tree_free(&istate->cache_tree);
istate->cache_tree = cache_tree();
prime_cache_tree_rec(r, istate->cache_tree, tree, &tree_path);
strbuf_release(&tree_path);
istate->cache_changed |= CACHE_TREE_CHANGED;
trace2_region_leave("cache-tree", "prime_cache_tree", r);
}
/*
* find the cache_tree that corresponds to the current level without
* exploding the full path into textual form. The root of the
* cache tree is given as "root", and our current level is "info".
* (1) When at root level, info->prev is NULL, so it is "root" itself.
* (2) Otherwise, find the cache_tree that corresponds to one level
* above us, and find ourselves in there.
*/
static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
struct traverse_info *info)
{
struct cache_tree *our_parent;
if (!info->prev)
return root;
our_parent = find_cache_tree_from_traversal(root, info->prev);
return cache_tree_find(our_parent, info->name);
}
int cache_tree_matches_traversal(struct cache_tree *root,
struct name_entry *ent,
struct traverse_info *info)
{
struct cache_tree *it;
it = find_cache_tree_from_traversal(root, info);
it = cache_tree_find(it, ent->path);
if (it && it->entry_count > 0 && oideq(&ent->oid, &it->oid))
return it->entry_count;
return 0;
}
static int verify_one_sparse(struct index_state *istate,
struct strbuf *path,
int pos)
{
struct cache_entry *ce = istate->cache[pos];
if (!S_ISSPARSEDIR(ce->ce_mode))
return error(_("directory '%s' is present in index, but not sparse"),
path->buf);
return 0;
}
/*
* Returns:
* 0 - Verification completed.
* 1 - Restart verification - a call to ensure_full_index() freed the cache
* tree that is being verified and verification needs to be restarted from
* the new toplevel cache tree.
* -1 - Verification failed.
*/
static int verify_one(struct repository *r,
struct index_state *istate,
struct cache_tree *it,
struct strbuf *path)
{
int i, pos, len = path->len;
struct strbuf tree_buf = STRBUF_INIT;
struct object_id new_oid;
int ret;
for (i = 0; i < it->subtree_nr; i++) {
strbuf_addf(path, "%s/", it->down[i]->name);
ret = verify_one(r, istate, it->down[i]->cache_tree, path);
if (ret)
goto out;
strbuf_setlen(path, len);
}
if (it->entry_count < 0 ||
/* no verification on tests (t7003) that replace trees */
lookup_replace_object(r, &it->oid) != &it->oid) {
ret = 0;
goto out;
}
if (path->len) {
/*
* If the index is sparse and the cache tree is not
* index_name_pos() may trigger ensure_full_index() which will
* free the tree that is being verified.
*/
int is_sparse = istate->sparse_index;
pos = index_name_pos(istate, path->buf, path->len);
if (is_sparse && !istate->sparse_index) {
ret = 1;
goto out;
}
if (pos >= 0) {
ret = verify_one_sparse(istate, path, pos);
goto out;
}
pos = -pos - 1;
} else {
pos = 0;
}
if (it->entry_count + pos > istate->cache_nr) {
ret = error(_("corrupted cache-tree has entries not present in index"));
goto out;
}
i = 0;
while (i < it->entry_count) {
struct cache_entry *ce = istate->cache[pos + i];
const char *slash;
struct cache_tree_sub *sub = NULL;
const struct object_id *oid;
const char *name;
unsigned mode;
int entlen;
if (ce->ce_flags & (CE_STAGEMASK | CE_INTENT_TO_ADD | CE_REMOVE)) {
ret = error(_("%s with flags 0x%x should not be in cache-tree"),
ce->name, ce->ce_flags);
goto out;
}
name = ce->name + path->len;
slash = strchr(name, '/');
if (slash) {
entlen = slash - name;
sub = find_subtree(it, ce->name + path->len, entlen, 0);
if (!sub || sub->cache_tree->entry_count < 0) {
ret = error(_("bad subtree '%.*s'"), entlen, name);
goto out;
}
oid = &sub->cache_tree->oid;
mode = S_IFDIR;
i += sub->cache_tree->entry_count;
} else {
oid = &ce->oid;
mode = ce->ce_mode;
entlen = ce_namelen(ce) - path->len;
i++;
}
strbuf_addf(&tree_buf, "%o %.*s%c", mode, entlen, name, '\0');
strbuf_add(&tree_buf, oid->hash, r->hash_algo->rawsz);
}
hash_object_file(r->hash_algo, tree_buf.buf, tree_buf.len, OBJ_TREE,
&new_oid);
if (!oideq(&new_oid, &it->oid)) {
ret = error(_("cache-tree for path %.*s does not match. "
"Expected %s got %s"), len, path->buf,
oid_to_hex(&new_oid), oid_to_hex(&it->oid));
goto out;
}
ret = 0;
out:
strbuf_setlen(path, len);
strbuf_release(&tree_buf);
return ret;
}
int cache_tree_verify(struct repository *r, struct index_state *istate)
{
struct strbuf path = STRBUF_INIT;
int ret;
if (!istate->cache_tree) {
ret = 0;
goto out;
}
ret = verify_one(r, istate, istate->cache_tree, &path);
if (ret < 0)
goto out;
if (ret > 0) {
strbuf_reset(&path);
ret = verify_one(r, istate, istate->cache_tree, &path);
if (ret < 0)
goto out;
if (ret > 0)
BUG("ensure_full_index() called twice while verifying cache tree");
}
ret = 0;
out:
strbuf_release(&path);
return ret;
}
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