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read-cache: fix leaking hashfile when writing index fails

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In `do_write_index()`, we use a `struct hashfile` to write the index
with a trailer hash. In case the write fails though, we never clean up
the allocated `hashfile` state and thus leak memory.

Refactor the code to have a common exit path where we can free this and
other allocated memory. While at it, refactor our use of `strbuf`s such
that we reuse the same buffer to avoid some unneeded allocations.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Patrick Steinhardt 2024-08-14 08:52:06 +02:00 committed by Junio C Hamano
parent c81dcf630c
commit d1c53f6703
4 changed files with 62 additions and 39 deletions
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97
read-cache.c
View file

@ -2840,8 +2840,9 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
int csum_fsync_flag;
int ieot_entries = 1;
struct index_entry_offset_table *ieot = NULL;
int nr, nr_threads;
struct repository *r = istate->repo;
struct strbuf sb = STRBUF_INIT;
int nr, nr_threads, ret;
f = hashfd(tempfile->fd, tempfile->filename.buf);
@ -2962,8 +2963,8 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
strbuf_release(&previous_name_buf);
if (err) {
free(ieot);
return err;
ret = err;
goto out;
}
offset = hashfile_total(f);
@ -2985,20 +2986,20 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
* index.
*/
if (ieot) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
write_ieot_extension(&sb, ieot);
err = write_index_ext_header(f, eoie_c, CACHE_EXT_INDEXENTRYOFFSETTABLE, sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
free(ieot);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
if (write_extensions & WRITE_SPLIT_INDEX_EXTENSION &&
istate->split_index) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
if (istate->sparse_index)
die(_("cannot write split index for a sparse index"));
@ -3007,59 +3008,66 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
write_index_ext_header(f, eoie_c, CACHE_EXT_LINK,
sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
if (write_extensions & WRITE_CACHE_TREE_EXTENSION &&
!drop_cache_tree && istate->cache_tree) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
cache_tree_write(&sb, istate->cache_tree);
err = write_index_ext_header(f, eoie_c, CACHE_EXT_TREE, sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
if (write_extensions & WRITE_RESOLVE_UNDO_EXTENSION &&
istate->resolve_undo) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
resolve_undo_write(&sb, istate->resolve_undo);
err = write_index_ext_header(f, eoie_c, CACHE_EXT_RESOLVE_UNDO,
sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
if (write_extensions & WRITE_UNTRACKED_CACHE_EXTENSION &&
istate->untracked) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
write_untracked_extension(&sb, istate->untracked);
err = write_index_ext_header(f, eoie_c, CACHE_EXT_UNTRACKED,
sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
if (write_extensions & WRITE_FSMONITOR_EXTENSION &&
istate->fsmonitor_last_update) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
write_fsmonitor_extension(&sb, istate);
err = write_index_ext_header(f, eoie_c, CACHE_EXT_FSMONITOR, sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
if (istate->sparse_index) {
if (write_index_ext_header(f, eoie_c, CACHE_EXT_SPARSE_DIRECTORIES, 0) < 0)
return -1;
if (write_index_ext_header(f, eoie_c, CACHE_EXT_SPARSE_DIRECTORIES, 0) < 0) {
ret = -1;
goto out;
}
}
/*
@ -3069,14 +3077,15 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
* when loading the shared index.
*/
if (eoie_c) {
struct strbuf sb = STRBUF_INIT;
strbuf_reset(&sb);
write_eoie_extension(&sb, eoie_c, offset);
err = write_index_ext_header(f, NULL, CACHE_EXT_ENDOFINDEXENTRIES, sb.len) < 0;
hashwrite(f, sb.buf, sb.len);
strbuf_release(&sb);
if (err)
return -1;
if (err) {
ret = -1;
goto out;
}
}
csum_fsync_flag = 0;
@ -3085,13 +3094,16 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
finalize_hashfile(f, istate->oid.hash, FSYNC_COMPONENT_INDEX,
CSUM_HASH_IN_STREAM | csum_fsync_flag);
f = NULL;
if (close_tempfile_gently(tempfile)) {
error(_("could not close '%s'"), get_tempfile_path(tempfile));
return -1;
ret = error(_("could not close '%s'"), get_tempfile_path(tempfile));
goto out;
}
if (stat(get_tempfile_path(tempfile), &st)) {
ret = -1;
goto out;
}
if (stat(get_tempfile_path(tempfile), &st))
return -1;
istate->timestamp.sec = (unsigned int)st.st_mtime;
istate->timestamp.nsec = ST_MTIME_NSEC(st);
trace_performance_since(start, "write index, changed mask = %x", istate->cache_changed);
@ -3105,7 +3117,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
trace2_data_intmax("index", the_repository, "write/cache_nr",
istate->cache_nr);
return 0;
ret = 0;
out:
if (f)
free_hashfile(f);
strbuf_release(&sb);
free(ieot);
return ret;
}
void set_alternate_index_output(const char *name)

2
t/t1601-index-bogus.sh
View file

@ -1,6 +1,8 @@
#!/bin/sh
test_description='test handling of bogus index entries'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
test_expect_success 'create tree with null sha1' '

1
t/t2107-update-index-basic.sh
View file

@ -5,6 +5,7 @@ test_description='basic update-index tests
Tests for command-line parsing and basic operation.
'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
test_expect_success 'update-index --nonsense fails' '

1
t/t7008-filter-branch-null-sha1.sh
View file

@ -2,6 +2,7 @@
test_description='filter-branch removal of trees with null sha1'
TEST_PASSES_SANITIZE_LEAK=true
. ./test-lib.sh
test_expect_success 'setup: base commits' '