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![Jeff Hostetler](/assets/img/avatar_default.png)
Copy the 'index_state->dir_hash' back to the real istate after expanding a sparse index. A crash was observed in 'git status' during some hashmap lookups with corrupted hashmap entries. During an index expansion, new cache-entries are added to the 'index_state->name_hash' and the 'dir_hash' in a temporary 'index_state' variable 'full'. However, only the 'name_hash' hashmap from this temp variable was copied back into the real 'istate' variable. The original copy of the 'dir_hash' was incorrectly preserved. If the table in the 'full->dir_hash' hashmap were realloced, the stale version (in 'istate') would be corrupted. The test suite does not operate on index sizes sufficiently large to trigger this reallocation, so they do not cover this behavior. Increasing the test suite to cover such scale is fragile and likely wasteful. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
378 lines
9.3 KiB
C
378 lines
9.3 KiB
C
#include "cache.h"
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#include "repository.h"
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#include "sparse-index.h"
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#include "tree.h"
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#include "pathspec.h"
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#include "trace2.h"
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#include "cache-tree.h"
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#include "config.h"
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#include "dir.h"
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#include "fsmonitor.h"
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static struct cache_entry *construct_sparse_dir_entry(
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struct index_state *istate,
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const char *sparse_dir,
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struct cache_tree *tree)
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{
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struct cache_entry *de;
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de = make_cache_entry(istate, S_IFDIR, &tree->oid, sparse_dir, 0, 0);
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de->ce_flags |= CE_SKIP_WORKTREE;
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return de;
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}
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/*
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* Returns the number of entries "inserted" into the index.
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*/
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static int convert_to_sparse_rec(struct index_state *istate,
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int num_converted,
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int start, int end,
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const char *ct_path, size_t ct_pathlen,
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struct cache_tree *ct)
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{
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int i, can_convert = 1;
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int start_converted = num_converted;
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enum pattern_match_result match;
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int dtype = DT_UNKNOWN;
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struct strbuf child_path = STRBUF_INIT;
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struct pattern_list *pl = istate->sparse_checkout_patterns;
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/*
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* Is the current path outside of the sparse cone?
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* Then check if the region can be replaced by a sparse
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* directory entry (everything is sparse and merged).
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*/
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match = path_matches_pattern_list(ct_path, ct_pathlen,
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NULL, &dtype, pl, istate);
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if (match != NOT_MATCHED)
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can_convert = 0;
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for (i = start; can_convert && i < end; i++) {
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struct cache_entry *ce = istate->cache[i];
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if (ce_stage(ce) ||
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S_ISGITLINK(ce->ce_mode) ||
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!(ce->ce_flags & CE_SKIP_WORKTREE))
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can_convert = 0;
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}
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if (can_convert) {
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struct cache_entry *se;
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se = construct_sparse_dir_entry(istate, ct_path, ct);
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istate->cache[num_converted++] = se;
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return 1;
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}
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for (i = start; i < end; ) {
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int count, span, pos = -1;
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const char *base, *slash;
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struct cache_entry *ce = istate->cache[i];
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/*
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* Detect if this is a normal entry outside of any subtree
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* entry.
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*/
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base = ce->name + ct_pathlen;
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slash = strchr(base, '/');
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if (slash)
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pos = cache_tree_subtree_pos(ct, base, slash - base);
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if (pos < 0) {
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istate->cache[num_converted++] = ce;
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i++;
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continue;
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}
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strbuf_setlen(&child_path, 0);
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strbuf_add(&child_path, ce->name, slash - ce->name + 1);
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span = ct->down[pos]->cache_tree->entry_count;
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count = convert_to_sparse_rec(istate,
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num_converted, i, i + span,
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child_path.buf, child_path.len,
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ct->down[pos]->cache_tree);
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num_converted += count;
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i += span;
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}
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strbuf_release(&child_path);
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return num_converted - start_converted;
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}
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int set_sparse_index_config(struct repository *repo, int enable)
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{
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int res;
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char *config_path = repo_git_path(repo, "config.worktree");
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res = git_config_set_in_file_gently(config_path,
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"index.sparse",
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enable ? "true" : NULL);
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free(config_path);
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prepare_repo_settings(repo);
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repo->settings.sparse_index = enable;
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return res;
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}
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static int index_has_unmerged_entries(struct index_state *istate)
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{
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int i;
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for (i = 0; i < istate->cache_nr; i++) {
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if (ce_stage(istate->cache[i]))
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return 1;
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}
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return 0;
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}
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int convert_to_sparse(struct index_state *istate)
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{
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int test_env;
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if (istate->split_index || istate->sparse_index ||
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!core_apply_sparse_checkout || !core_sparse_checkout_cone)
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return 0;
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if (!istate->repo)
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istate->repo = the_repository;
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/*
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* The GIT_TEST_SPARSE_INDEX environment variable triggers the
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* index.sparse config variable to be on.
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*/
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test_env = git_env_bool("GIT_TEST_SPARSE_INDEX", -1);
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if (test_env >= 0)
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set_sparse_index_config(istate->repo, test_env);
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/*
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* Only convert to sparse if index.sparse is set.
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*/
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prepare_repo_settings(istate->repo);
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if (!istate->repo->settings.sparse_index)
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return 0;
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if (!istate->sparse_checkout_patterns) {
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istate->sparse_checkout_patterns = xcalloc(1, sizeof(struct pattern_list));
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if (get_sparse_checkout_patterns(istate->sparse_checkout_patterns) < 0)
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return 0;
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}
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if (!istate->sparse_checkout_patterns->use_cone_patterns) {
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warning(_("attempting to use sparse-index without cone mode"));
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return -1;
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}
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/*
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* NEEDSWORK: If we have unmerged entries, then stay full.
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* Unmerged entries prevent the cache-tree extension from working.
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*/
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if (index_has_unmerged_entries(istate))
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return 0;
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/* Clear and recompute the cache-tree */
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cache_tree_free(&istate->cache_tree);
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if (cache_tree_update(istate, 0)) {
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warning(_("unable to update cache-tree, staying full"));
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return -1;
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}
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remove_fsmonitor(istate);
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trace2_region_enter("index", "convert_to_sparse", istate->repo);
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istate->cache_nr = convert_to_sparse_rec(istate,
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0, 0, istate->cache_nr,
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"", 0, istate->cache_tree);
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/* Clear and recompute the cache-tree */
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cache_tree_free(&istate->cache_tree);
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cache_tree_update(istate, 0);
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istate->fsmonitor_has_run_once = 0;
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FREE_AND_NULL(istate->fsmonitor_dirty);
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FREE_AND_NULL(istate->fsmonitor_last_update);
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istate->sparse_index = 1;
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trace2_region_leave("index", "convert_to_sparse", istate->repo);
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return 0;
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}
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static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce)
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{
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ALLOC_GROW(istate->cache, nr + 1, istate->cache_alloc);
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istate->cache[nr] = ce;
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add_name_hash(istate, ce);
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}
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static int add_path_to_index(const struct object_id *oid,
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struct strbuf *base, const char *path,
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unsigned int mode, void *context)
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{
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struct index_state *istate = (struct index_state *)context;
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struct cache_entry *ce;
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size_t len = base->len;
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if (S_ISDIR(mode))
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return READ_TREE_RECURSIVE;
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strbuf_addstr(base, path);
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ce = make_cache_entry(istate, mode, oid, base->buf, 0, 0);
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ce->ce_flags |= CE_SKIP_WORKTREE | CE_EXTENDED;
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set_index_entry(istate, istate->cache_nr++, ce);
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strbuf_setlen(base, len);
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return 0;
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}
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void ensure_full_index(struct index_state *istate)
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{
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int i;
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struct index_state *full;
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struct strbuf base = STRBUF_INIT;
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if (!istate || !istate->sparse_index)
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return;
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if (!istate->repo)
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istate->repo = the_repository;
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trace2_region_enter("index", "ensure_full_index", istate->repo);
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/* initialize basics of new index */
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full = xcalloc(1, sizeof(struct index_state));
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memcpy(full, istate, sizeof(struct index_state));
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/* then change the necessary things */
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full->sparse_index = 0;
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full->cache_alloc = (3 * istate->cache_alloc) / 2;
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full->cache_nr = 0;
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ALLOC_ARRAY(full->cache, full->cache_alloc);
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for (i = 0; i < istate->cache_nr; i++) {
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struct cache_entry *ce = istate->cache[i];
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struct tree *tree;
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struct pathspec ps;
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if (!S_ISSPARSEDIR(ce->ce_mode)) {
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set_index_entry(full, full->cache_nr++, ce);
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continue;
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}
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if (!(ce->ce_flags & CE_SKIP_WORKTREE))
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warning(_("index entry is a directory, but not sparse (%08x)"),
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ce->ce_flags);
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/* recursively walk into cd->name */
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tree = lookup_tree(istate->repo, &ce->oid);
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memset(&ps, 0, sizeof(ps));
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ps.recursive = 1;
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ps.has_wildcard = 1;
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ps.max_depth = -1;
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strbuf_setlen(&base, 0);
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strbuf_add(&base, ce->name, strlen(ce->name));
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read_tree_at(istate->repo, tree, &base, &ps,
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add_path_to_index, full);
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/* free directory entries. full entries are re-used */
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discard_cache_entry(ce);
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}
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/* Copy back into original index. */
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memcpy(&istate->name_hash, &full->name_hash, sizeof(full->name_hash));
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memcpy(&istate->dir_hash, &full->dir_hash, sizeof(full->dir_hash));
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istate->sparse_index = 0;
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free(istate->cache);
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istate->cache = full->cache;
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istate->cache_nr = full->cache_nr;
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istate->cache_alloc = full->cache_alloc;
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istate->fsmonitor_has_run_once = 0;
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FREE_AND_NULL(istate->fsmonitor_dirty);
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FREE_AND_NULL(istate->fsmonitor_last_update);
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strbuf_release(&base);
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free(full);
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/* Clear and recompute the cache-tree */
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cache_tree_free(&istate->cache_tree);
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cache_tree_update(istate, 0);
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trace2_region_leave("index", "ensure_full_index", istate->repo);
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}
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/*
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* This static global helps avoid infinite recursion between
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* expand_to_path() and index_file_exists().
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*/
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static int in_expand_to_path = 0;
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void expand_to_path(struct index_state *istate,
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const char *path, size_t pathlen, int icase)
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{
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struct strbuf path_mutable = STRBUF_INIT;
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size_t substr_len;
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/* prevent extra recursion */
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if (in_expand_to_path)
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return;
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if (!istate || !istate->sparse_index)
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return;
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if (!istate->repo)
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istate->repo = the_repository;
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in_expand_to_path = 1;
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/*
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* We only need to actually expand a region if the
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* following are both true:
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*
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* 1. 'path' is not already in the index.
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* 2. Some parent directory of 'path' is a sparse directory.
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*/
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if (index_file_exists(istate, path, pathlen, icase))
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goto cleanup;
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strbuf_add(&path_mutable, path, pathlen);
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strbuf_addch(&path_mutable, '/');
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/* Check the name hash for all parent directories */
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substr_len = 0;
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while (substr_len < pathlen) {
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char temp;
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char *replace = strchr(path_mutable.buf + substr_len, '/');
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if (!replace)
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break;
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/* replace the character _after_ the slash */
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replace++;
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temp = *replace;
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*replace = '\0';
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if (index_file_exists(istate, path_mutable.buf,
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path_mutable.len, icase)) {
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/*
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* We found a parent directory in the name-hash
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* hashtable, because only sparse directory entries
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* have a trailing '/' character. Since "path" wasn't
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* in the index, perhaps it exists within this
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* sparse-directory. Expand accordingly.
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*/
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ensure_full_index(istate);
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break;
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}
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*replace = temp;
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substr_len = replace - path_mutable.buf;
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}
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cleanup:
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strbuf_release(&path_mutable);
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in_expand_to_path = 0;
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}
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