git/builtin/checkout-index.c
Eric Sunshine 74c4de5832 checkout-index: fix --temp relative path mangling
checkout-index --temp only properly prints relative paths which are
descendants of the current directory. Paths in ancestor or sibling
directories (or their children) are often printed in mangled form. For
example:

    mkdir a bbb &&
    >file &&
    >bbb/file &&
    git update-index --add file bbb/file &&
    cd a &&
    git checkout-index --temp ../file ../bbb/file

prints:

    .merge_file_ooblek  le
    .merge_file_igloo0  b/file

rather than the correct:

    .merge_file_ooblek  ../file
    .merge_file_igloo0  ../bbb/file

Internally, given the above example, checkout-index prefixes each input
argument with the name of the current directory ("a/", in this case),
and then assumes that it can simply skip forward by strlen("a/") bytes
to recover the original name. This works for files in the current
directory or its descendants, but fails for files in ancestors or
siblings (or their children) due to path normalization.

For instance, given "../file", "a/" is prepended, giving "a/../file".
Path normalization folds out "a/../", resulting in "file". Attempting
to recover the original name by skipping strlen("a/") bytes gives the
incorrect "le" rather than the desired "../file".

Fix this by taking advantage of write_name_quoted_relative() to recover
the original name properly, rather than assuming that it can be
recovered by skipping strlen(prefix) bytes.

As a bonus, this also fixes a bug in which checkout-index --temp
accessed and printed memory beyond the end-of-string. For instance,
within a subdirectory named "subdirectory", and given argument
"../file", prefixing would give "subdirectory/../file", which would
become "file" after normalization. checkout-index would then attempt to
recover the original name by skipping strlen("subdirectory/") bytes of
"file", which placed it well beyond end-of-string. Despite this error,
it often appeared to give the correct result, but only due to an
accident of implementation which left an apparently correct copy of the
path in memory following the normalized value. In particular, handed
"subdirectory/../file", in-place processing by normalize_path_copy_len()
resulted in "file\0rectory/../file". When checkout-index skipped
strlen("subdirectory/") bytes, it ended up back at "../file" and thus
appeared to give the correct answer, despite being past end-of-string.

Reported-by: Russ Cox <rsc@golang.org>
Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-12-29 10:58:45 -08:00

287 lines
7 KiB
C

/*
* Check-out files from the "current cache directory"
*
* Copyright (C) 2005 Linus Torvalds
*
*/
#include "builtin.h"
#include "cache.h"
#include "quote.h"
#include "cache-tree.h"
#include "parse-options.h"
#define CHECKOUT_ALL 4
static int line_termination = '\n';
static int checkout_stage; /* default to checkout stage0 */
static int to_tempfile;
static char topath[4][TEMPORARY_FILENAME_LENGTH + 1];
static struct checkout state;
static void write_tempfile_record(const char *name, const char *prefix)
{
int i;
if (CHECKOUT_ALL == checkout_stage) {
for (i = 1; i < 4; i++) {
if (i > 1)
putchar(' ');
if (topath[i][0])
fputs(topath[i], stdout);
else
putchar('.');
}
} else
fputs(topath[checkout_stage], stdout);
putchar('\t');
write_name_quoted_relative(name, prefix, stdout, line_termination);
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 = cache_name_pos(name, namelen);
int has_same_name = 0;
int did_checkout = 0;
int errs = 0;
if (pos < 0)
pos = -pos - 1;
while (pos < active_nr) {
struct cache_entry *ce = active_cache[pos];
if (ce_namelen(ce) != namelen ||
memcmp(ce->name, name, namelen))
break;
has_same_name = 1;
pos++;
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) < 0)
errs++;
}
if (did_checkout) {
if (to_tempfile)
write_tempfile_record(name, prefix);
return errs > 0 ? -1 : 0;
}
if (!state.quiet) {
fprintf(stderr, "git checkout-index: %s ", name);
if (!has_same_name)
fprintf(stderr, "is not in the cache");
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 void checkout_all(const char *prefix, int prefix_length)
{
int i, errs = 0;
struct cache_entry *last_ce = NULL;
for (i = 0; i < active_nr ; i++) {
struct cache_entry *ce = active_cache[i];
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) < 0)
errs++;
last_ce = ce;
}
if (last_ce && to_tempfile)
write_tempfile_record(last_ce->name, prefix);
if (errs)
/* we have already done our error reporting.
* exit with the same code as die().
*/
exit(128);
}
static const char * const builtin_checkout_index_usage[] = {
N_("git checkout-index [options] [--] [<file>...]"),
NULL
};
static struct lock_file lock_file;
static int option_parse_u(const struct option *opt,
const char *arg, int unset)
{
int *newfd = opt->value;
state.refresh_cache = 1;
if (*newfd < 0)
*newfd = hold_locked_index(&lock_file, 1);
return 0;
}
static int option_parse_z(const struct option *opt,
const char *arg, int unset)
{
if (unset)
line_termination = '\n';
else
line_termination = 0;
return 0;
}
static int option_parse_prefix(const struct option *opt,
const char *arg, int unset)
{
state.base_dir = arg;
state.base_dir_len = strlen(arg);
return 0;
}
static int option_parse_stage(const struct option *opt,
const char *arg, int 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;
int newfd = -1;
int all = 0;
int read_from_stdin = 0;
int prefix_length;
int force = 0, quiet = 0, not_new = 0;
struct option builtin_checkout_index_options[] = {
OPT_BOOL('a', "all", &all,
N_("check out all files in the index")),
OPT__FORCE(&force, N_("force overwrite of existing files")),
OPT__QUIET(&quiet,
N_("no warning for existing files and files not in index")),
OPT_BOOL('n', "no-create", &not_new,
N_("don't checkout new files")),
{ OPTION_CALLBACK, 'u', "index", &newfd, NULL,
N_("update stat information in the index file"),
PARSE_OPT_NOARG, option_parse_u },
{ OPTION_CALLBACK, 'z', NULL, NULL, NULL,
N_("paths are separated with NUL character"),
PARSE_OPT_NOARG, option_parse_z },
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_CALLBACK(0, "prefix", NULL, N_("string"),
N_("when creating files, prepend <string>"),
option_parse_prefix),
OPT_CALLBACK(0, "stage", NULL, NULL,
N_("copy out the files from named stage"),
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);
state.base_dir = "";
prefix_length = prefix ? strlen(prefix) : 0;
if (read_cache() < 0) {
die("invalid cache");
}
argc = parse_options(argc, argv, prefix, builtin_checkout_index_options,
builtin_checkout_index_usage, 0);
state.force = force;
state.quiet = quiet;
state.not_new = not_new;
if (state.base_dir_len || to_tempfile) {
/* when --prefix is specified we do not
* want to update cache.
*/
if (state.refresh_cache) {
rollback_lock_file(&lock_file);
newfd = -1;
}
state.refresh_cache = 0;
}
/* Check out named files first */
for (i = 0; i < argc; i++) {
const char *arg = argv[i];
const 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);
checkout_file(p, prefix);
if (p < arg || p > arg + strlen(arg))
free((char *)p);
}
if (read_from_stdin) {
struct strbuf buf = STRBUF_INIT, nbuf = STRBUF_INIT;
if (all)
die("git checkout-index: don't mix '--all' and '--stdin'");
while (strbuf_getline(&buf, stdin, line_termination) != EOF) {
const char *p;
if (line_termination && buf.buf[0] == '"') {
strbuf_reset(&nbuf);
if (unquote_c_style(&nbuf, buf.buf, NULL))
die("line is badly quoted");
strbuf_swap(&buf, &nbuf);
}
p = prefix_path(prefix, prefix_length, buf.buf);
checkout_file(p, prefix);
if (p < buf.buf || p > buf.buf + buf.len)
free((char *)p);
}
strbuf_release(&nbuf);
strbuf_release(&buf);
}
if (all)
checkout_all(prefix, prefix_length);
if (0 <= newfd &&
(write_cache(newfd, active_cache, active_nr) ||
commit_locked_index(&lock_file)))
die("Unable to write new index file");
return 0;
}