Revision 9cf85473209ea8ae2b56c13145c4704d12ee1374 authored by Filip Hejsek on 28 January 2024, 04:09:17 UTC, committed by Johannes Schindelin on 17 April 2024, 20:30:01 UTC
While it is expected to have several git dirs within the `.git/modules/` tree, it is important that they do not interfere with each other. For example, if one submodule was called "captain" and another submodule "captain/hooks", their respective git dirs would clash, as they would be located in `.git/modules/captain/` and `.git/modules/captain/hooks/`, respectively, i.e. the latter's files could clash with the actual Git hooks of the former. To prevent these clashes, and in particular to prevent hooks from being written and then executed as part of a recursive clone, we introduced checks as part of the fix for CVE-2019-1387 in a8dee3ca61 (Disallow dubiously-nested submodule git directories, 2019-10-01). It is currently possible to bypass the check for clashing submodule git dirs in two ways: 1. parallel cloning 2. checkout --recurse-submodules Let's check not only before, but also after parallel cloning (and before checking out the submodule), that the git dir is not clashing with another one, otherwise fail. This addresses the parallel cloning issue. As to the parallel checkout issue: It requires quite a few manual steps to create clashing git dirs because Git itself would refuse to initialize the inner one, as demonstrated by the test case. Nevertheless, let's teach the recursive checkout (namely, the `submodule_move_head()` function that is used by the recursive checkout) to be careful to verify that it does not use a clashing git dir, and if it does, disable it (by deleting the `HEAD` file so that subsequent Git calls won't recognize it as a git dir anymore). Note: The parallel cloning test case contains a `cat err` that proved to be highly useful when analyzing the racy nature of the operation (the operation can fail with three different error messages, depending on timing), and was left on purpose to ease future debugging should the need arise. Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
1 parent b20c10f
checkout-index.c
/*
* Check-out files from the "current cache directory"
*
* Copyright (C) 2005 Linus Torvalds
*
*/
#define USE_THE_INDEX_VARIABLE
#include "builtin.h"
#include "config.h"
#include "dir.h"
#include "lockfile.h"
#include "quote.h"
#include "cache-tree.h"
#include "parse-options.h"
#include "entry.h"
#include "parallel-checkout.h"
#define CHECKOUT_ALL 4
static int nul_term_line;
static int checkout_stage; /* default to checkout stage0 */
static int ignore_skip_worktree; /* default to 0 */
static int to_tempfile;
static char topath[4][TEMPORARY_FILENAME_LENGTH + 1];
static struct checkout state = CHECKOUT_INIT;
static void write_tempfile_record(const char *name, const char *prefix)
{
int i;
int have_tempname = 0;
if (CHECKOUT_ALL == checkout_stage) {
for (i = 1; i < 4; i++)
if (topath[i][0]) {
have_tempname = 1;
break;
}
if (have_tempname) {
for (i = 1; i < 4; i++) {
if (i > 1)
putchar(' ');
if (topath[i][0])
fputs(topath[i], stdout);
else
putchar('.');
}
}
} else if (topath[checkout_stage][0]) {
have_tempname = 1;
fputs(topath[checkout_stage], stdout);
}
if (have_tempname) {
putchar('\t');
write_name_quoted_relative(name, prefix, stdout,
nul_term_line ? '\0' : '\n');
}
for (i = 0; i < 4; i++) {
topath[i][0] = 0;
}
}
static int checkout_file(const char *name, const char *prefix)
{
int namelen = strlen(name);
int pos = index_name_pos(&the_index, name, namelen);
int has_same_name = 0;
int is_file = 0;
int is_skipped = 1;
int did_checkout = 0;
int errs = 0;
if (pos < 0)
pos = -pos - 1;
while (pos < the_index.cache_nr) {
struct cache_entry *ce = the_index.cache[pos];
if (ce_namelen(ce) != namelen ||
memcmp(ce->name, name, namelen))
break;
has_same_name = 1;
pos++;
if (S_ISSPARSEDIR(ce->ce_mode))
break;
is_file = 1;
if (!ignore_skip_worktree && ce_skip_worktree(ce))
break;
is_skipped = 0;
if (ce_stage(ce) != checkout_stage
&& (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
continue;
did_checkout = 1;
if (checkout_entry(ce, &state,
to_tempfile ? topath[ce_stage(ce)] : NULL,
NULL) < 0)
errs++;
}
if (did_checkout) {
if (to_tempfile)
write_tempfile_record(name, prefix);
return errs > 0 ? -1 : 0;
}
/*
* At this point we know we didn't try to check anything out. If it was
* because we did find an entry but it was stage 0, that's not an
* error.
*/
if (has_same_name && checkout_stage == CHECKOUT_ALL)
return 0;
if (!state.quiet) {
fprintf(stderr, "git checkout-index: %s ", name);
if (!has_same_name)
fprintf(stderr, "is not in the cache");
else if (!is_file)
fprintf(stderr, "is a sparse directory");
else if (is_skipped)
fprintf(stderr, "has skip-worktree enabled; "
"use '--ignore-skip-worktree-bits' to checkout");
else if (checkout_stage)
fprintf(stderr, "does not exist at stage %d",
checkout_stage);
else
fprintf(stderr, "is unmerged");
fputc('\n', stderr);
}
return -1;
}
static int checkout_all(const char *prefix, int prefix_length)
{
int i, errs = 0;
struct cache_entry *last_ce = NULL;
for (i = 0; i < the_index.cache_nr ; i++) {
struct cache_entry *ce = the_index.cache[i];
if (S_ISSPARSEDIR(ce->ce_mode)) {
if (!ce_skip_worktree(ce))
BUG("sparse directory '%s' does not have skip-worktree set", ce->name);
/*
* If the current entry is a sparse directory and skip-worktree
* entries are being checked out, expand the index and continue
* the loop on the current index position (now pointing to the
* first entry inside the expanded sparse directory).
*/
if (ignore_skip_worktree) {
ensure_full_index(&the_index);
ce = the_index.cache[i];
}
}
if (!ignore_skip_worktree && ce_skip_worktree(ce))
continue;
if (ce_stage(ce) != checkout_stage
&& (CHECKOUT_ALL != checkout_stage || !ce_stage(ce)))
continue;
if (prefix && *prefix &&
(ce_namelen(ce) <= prefix_length ||
memcmp(prefix, ce->name, prefix_length)))
continue;
if (last_ce && to_tempfile) {
if (ce_namelen(last_ce) != ce_namelen(ce)
|| memcmp(last_ce->name, ce->name, ce_namelen(ce)))
write_tempfile_record(last_ce->name, prefix);
}
if (checkout_entry(ce, &state,
to_tempfile ? topath[ce_stage(ce)] : NULL,
NULL) < 0)
errs++;
last_ce = ce;
}
if (last_ce && to_tempfile)
write_tempfile_record(last_ce->name, prefix);
return !!errs;
}
static const char * const builtin_checkout_index_usage[] = {
N_("git checkout-index [<options>] [--] [<file>...]"),
NULL
};
static int option_parse_stage(const struct option *opt,
const char *arg, int unset)
{
BUG_ON_OPT_NEG(unset);
if (!strcmp(arg, "all")) {
to_tempfile = 1;
checkout_stage = CHECKOUT_ALL;
} else {
int ch = arg[0];
if ('1' <= ch && ch <= '3')
checkout_stage = arg[0] - '0';
else
die(_("stage should be between 1 and 3 or all"));
}
return 0;
}
int cmd_checkout_index(int argc, const char **argv, const char *prefix)
{
int i;
struct lock_file lock_file = LOCK_INIT;
int all = 0;
int read_from_stdin = 0;
int prefix_length;
int force = 0, quiet = 0, not_new = 0;
int index_opt = 0;
int err = 0;
int pc_workers, pc_threshold;
struct option builtin_checkout_index_options[] = {
OPT_BOOL('a', "all", &all,
N_("check out all files in the index")),
OPT_BOOL(0, "ignore-skip-worktree-bits", &ignore_skip_worktree,
N_("do not skip files with skip-worktree set")),
OPT__FORCE(&force, N_("force overwrite of existing files"), 0),
OPT__QUIET(&quiet,
N_("no warning for existing files and files not in index")),
OPT_BOOL('n', "no-create", ¬_new,
N_("don't checkout new files")),
OPT_BOOL('u', "index", &index_opt,
N_("update stat information in the index file")),
OPT_BOOL('z', NULL, &nul_term_line,
N_("paths are separated with NUL character")),
OPT_BOOL(0, "stdin", &read_from_stdin,
N_("read list of paths from the standard input")),
OPT_BOOL(0, "temp", &to_tempfile,
N_("write the content to temporary files")),
OPT_STRING(0, "prefix", &state.base_dir, N_("string"),
N_("when creating files, prepend <string>")),
OPT_CALLBACK_F(0, "stage", NULL, "(1|2|3|all)",
N_("copy out the files from named stage"),
PARSE_OPT_NONEG, option_parse_stage),
OPT_END()
};
if (argc == 2 && !strcmp(argv[1], "-h"))
usage_with_options(builtin_checkout_index_usage,
builtin_checkout_index_options);
git_config(git_default_config, NULL);
prefix_length = prefix ? strlen(prefix) : 0;
prepare_repo_settings(the_repository);
the_repository->settings.command_requires_full_index = 0;
if (repo_read_index(the_repository) < 0) {
die("invalid cache");
}
argc = parse_options(argc, argv, prefix, builtin_checkout_index_options,
builtin_checkout_index_usage, 0);
state.istate = &the_index;
state.force = force;
state.quiet = quiet;
state.not_new = not_new;
if (!state.base_dir)
state.base_dir = "";
state.base_dir_len = strlen(state.base_dir);
/*
* when --prefix is specified we do not want to update cache.
*/
if (index_opt && !state.base_dir_len && !to_tempfile) {
state.refresh_cache = 1;
state.istate = &the_index;
repo_hold_locked_index(the_repository, &lock_file,
LOCK_DIE_ON_ERROR);
}
get_parallel_checkout_configs(&pc_workers, &pc_threshold);
if (pc_workers > 1)
init_parallel_checkout();
/* Check out named files first */
for (i = 0; i < argc; i++) {
const char *arg = argv[i];
char *p;
if (all)
die("git checkout-index: don't mix '--all' and explicit filenames");
if (read_from_stdin)
die("git checkout-index: don't mix '--stdin' and explicit filenames");
p = prefix_path(prefix, prefix_length, arg);
err |= checkout_file(p, prefix);
free(p);
}
if (read_from_stdin) {
struct strbuf buf = STRBUF_INIT;
struct strbuf unquoted = STRBUF_INIT;
strbuf_getline_fn getline_fn;
if (all)
die("git checkout-index: don't mix '--all' and '--stdin'");
getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
while (getline_fn(&buf, stdin) != EOF) {
char *p;
if (!nul_term_line && buf.buf[0] == '"') {
strbuf_reset(&unquoted);
if (unquote_c_style(&unquoted, buf.buf, NULL))
die("line is badly quoted");
strbuf_swap(&buf, &unquoted);
}
p = prefix_path(prefix, prefix_length, buf.buf);
err |= checkout_file(p, prefix);
free(p);
}
strbuf_release(&unquoted);
strbuf_release(&buf);
}
if (all)
err |= checkout_all(prefix, prefix_length);
if (pc_workers > 1)
err |= run_parallel_checkout(&state, pc_workers, pc_threshold,
NULL, NULL);
if (err)
return 1;
if (is_lock_file_locked(&lock_file) &&
write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
die("Unable to write new index file");
return 0;
}
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...