git/builtin/worktree.c
Jeff King 3733e69464 use xmallocz to avoid size arithmetic
We frequently allocate strings as xmalloc(len + 1), where
the extra 1 is for the NUL terminator. This can be done more
simply with xmallocz, which also checks for integer
overflow.

There's no case where switching xmalloc(n+1) to xmallocz(n)
is wrong; the result is the same length, and malloc made no
guarantees about what was in the buffer anyway. But in some
cases, we can stop manually placing NUL at the end of the
allocated buffer. But that's only safe if it's clear that
the contents will always fill the buffer.

In each case where this patch does so, I manually examined
the control flow, and I tried to err on the side of caution.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00

464 lines
12 KiB
C

#include "cache.h"
#include "builtin.h"
#include "dir.h"
#include "parse-options.h"
#include "argv-array.h"
#include "branch.h"
#include "refs.h"
#include "run-command.h"
#include "sigchain.h"
#include "refs.h"
#include "utf8.h"
#include "worktree.h"
static const char * const worktree_usage[] = {
N_("git worktree add [<options>] <path> [<branch>]"),
N_("git worktree prune [<options>]"),
N_("git worktree list [<options>]"),
NULL
};
struct add_opts {
int force;
int detach;
const char *new_branch;
int force_new_branch;
};
static int show_only;
static int verbose;
static unsigned long expire;
static int prune_worktree(const char *id, struct strbuf *reason)
{
struct stat st;
char *path;
int fd, len;
if (!is_directory(git_path("worktrees/%s", id))) {
strbuf_addf(reason, _("Removing worktrees/%s: not a valid directory"), id);
return 1;
}
if (file_exists(git_path("worktrees/%s/locked", id)))
return 0;
if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
strbuf_addf(reason, _("Removing worktrees/%s: gitdir file does not exist"), id);
return 1;
}
fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
if (fd < 0) {
strbuf_addf(reason, _("Removing worktrees/%s: unable to read gitdir file (%s)"),
id, strerror(errno));
return 1;
}
len = st.st_size;
path = xmallocz(len);
read_in_full(fd, path, len);
close(fd);
while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
len--;
if (!len) {
strbuf_addf(reason, _("Removing worktrees/%s: invalid gitdir file"), id);
free(path);
return 1;
}
path[len] = '\0';
if (!file_exists(path)) {
struct stat st_link;
free(path);
/*
* the repo is moved manually and has not been
* accessed since?
*/
if (!stat(git_path("worktrees/%s/link", id), &st_link) &&
st_link.st_nlink > 1)
return 0;
if (st.st_mtime <= expire) {
strbuf_addf(reason, _("Removing worktrees/%s: gitdir file points to non-existent location"), id);
return 1;
} else {
return 0;
}
}
free(path);
return 0;
}
static void prune_worktrees(void)
{
struct strbuf reason = STRBUF_INIT;
struct strbuf path = STRBUF_INIT;
DIR *dir = opendir(git_path("worktrees"));
struct dirent *d;
int ret;
if (!dir)
return;
while ((d = readdir(dir)) != NULL) {
if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
continue;
strbuf_reset(&reason);
if (!prune_worktree(d->d_name, &reason))
continue;
if (show_only || verbose)
printf("%s\n", reason.buf);
if (show_only)
continue;
strbuf_reset(&path);
strbuf_addstr(&path, git_path("worktrees/%s", d->d_name));
ret = remove_dir_recursively(&path, 0);
if (ret < 0 && errno == ENOTDIR)
ret = unlink(path.buf);
if (ret)
error(_("failed to remove: %s"), strerror(errno));
}
closedir(dir);
if (!show_only)
rmdir(git_path("worktrees"));
strbuf_release(&reason);
strbuf_release(&path);
}
static int prune(int ac, const char **av, const char *prefix)
{
struct option options[] = {
OPT__DRY_RUN(&show_only, N_("do not remove, show only")),
OPT__VERBOSE(&verbose, N_("report pruned objects")),
OPT_EXPIRY_DATE(0, "expire", &expire,
N_("expire objects older than <time>")),
OPT_END()
};
expire = ULONG_MAX;
ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
if (ac)
usage_with_options(worktree_usage, options);
prune_worktrees();
return 0;
}
static char *junk_work_tree;
static char *junk_git_dir;
static int is_junk;
static pid_t junk_pid;
static void remove_junk(void)
{
struct strbuf sb = STRBUF_INIT;
if (!is_junk || getpid() != junk_pid)
return;
if (junk_git_dir) {
strbuf_addstr(&sb, junk_git_dir);
remove_dir_recursively(&sb, 0);
strbuf_reset(&sb);
}
if (junk_work_tree) {
strbuf_addstr(&sb, junk_work_tree);
remove_dir_recursively(&sb, 0);
}
strbuf_release(&sb);
}
static void remove_junk_on_signal(int signo)
{
remove_junk();
sigchain_pop(signo);
raise(signo);
}
static const char *worktree_basename(const char *path, int *olen)
{
const char *name;
int len;
len = strlen(path);
while (len && is_dir_sep(path[len - 1]))
len--;
for (name = path + len - 1; name > path; name--)
if (is_dir_sep(*name)) {
name++;
break;
}
*olen = len;
return name;
}
static int add_worktree(const char *path, const char *refname,
const struct add_opts *opts)
{
struct strbuf sb_git = STRBUF_INIT, sb_repo = STRBUF_INIT;
struct strbuf sb = STRBUF_INIT;
const char *name;
struct stat st;
struct child_process cp;
struct argv_array child_env = ARGV_ARRAY_INIT;
int counter = 0, len, ret;
struct strbuf symref = STRBUF_INIT;
struct commit *commit = NULL;
if (file_exists(path) && !is_empty_dir(path))
die(_("'%s' already exists"), path);
/* is 'refname' a branch or commit? */
if (opts->force_new_branch) /* definitely a branch */
;
else if (!opts->detach && !strbuf_check_branch_ref(&symref, refname) &&
ref_exists(symref.buf)) { /* it's a branch */
if (!opts->force)
die_if_checked_out(symref.buf);
} else { /* must be a commit */
commit = lookup_commit_reference_by_name(refname);
if (!commit)
die(_("invalid reference: %s"), refname);
}
name = worktree_basename(path, &len);
strbuf_addstr(&sb_repo,
git_path("worktrees/%.*s", (int)(path + len - name), name));
len = sb_repo.len;
if (safe_create_leading_directories_const(sb_repo.buf))
die_errno(_("could not create leading directories of '%s'"),
sb_repo.buf);
while (!stat(sb_repo.buf, &st)) {
counter++;
strbuf_setlen(&sb_repo, len);
strbuf_addf(&sb_repo, "%d", counter);
}
name = strrchr(sb_repo.buf, '/') + 1;
junk_pid = getpid();
atexit(remove_junk);
sigchain_push_common(remove_junk_on_signal);
if (mkdir(sb_repo.buf, 0777))
die_errno(_("could not create directory of '%s'"), sb_repo.buf);
junk_git_dir = xstrdup(sb_repo.buf);
is_junk = 1;
/*
* lock the incomplete repo so prune won't delete it, unlock
* after the preparation is over.
*/
strbuf_addf(&sb, "%s/locked", sb_repo.buf);
write_file(sb.buf, "initializing");
strbuf_addf(&sb_git, "%s/.git", path);
if (safe_create_leading_directories_const(sb_git.buf))
die_errno(_("could not create leading directories of '%s'"),
sb_git.buf);
junk_work_tree = xstrdup(path);
strbuf_reset(&sb);
strbuf_addf(&sb, "%s/gitdir", sb_repo.buf);
write_file(sb.buf, "%s", real_path(sb_git.buf));
write_file(sb_git.buf, "gitdir: %s/worktrees/%s",
real_path(get_git_common_dir()), name);
/*
* This is to keep resolve_ref() happy. We need a valid HEAD
* or is_git_directory() will reject the directory. Any value which
* looks like an object ID will do since it will be immediately
* replaced by the symbolic-ref or update-ref invocation in the new
* worktree.
*/
strbuf_reset(&sb);
strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);
write_file(sb.buf, "0000000000000000000000000000000000000000");
strbuf_reset(&sb);
strbuf_addf(&sb, "%s/commondir", sb_repo.buf);
write_file(sb.buf, "../..");
fprintf_ln(stderr, _("Preparing %s (identifier %s)"), path, name);
argv_array_pushf(&child_env, "%s=%s", GIT_DIR_ENVIRONMENT, sb_git.buf);
argv_array_pushf(&child_env, "%s=%s", GIT_WORK_TREE_ENVIRONMENT, path);
memset(&cp, 0, sizeof(cp));
cp.git_cmd = 1;
if (commit)
argv_array_pushl(&cp.args, "update-ref", "HEAD",
oid_to_hex(&commit->object.oid), NULL);
else
argv_array_pushl(&cp.args, "symbolic-ref", "HEAD",
symref.buf, NULL);
cp.env = child_env.argv;
ret = run_command(&cp);
if (ret)
goto done;
cp.argv = NULL;
argv_array_clear(&cp.args);
argv_array_pushl(&cp.args, "reset", "--hard", NULL);
cp.env = child_env.argv;
ret = run_command(&cp);
if (!ret) {
is_junk = 0;
free(junk_work_tree);
free(junk_git_dir);
junk_work_tree = NULL;
junk_git_dir = NULL;
}
done:
strbuf_reset(&sb);
strbuf_addf(&sb, "%s/locked", sb_repo.buf);
unlink_or_warn(sb.buf);
argv_array_clear(&child_env);
strbuf_release(&sb);
strbuf_release(&symref);
strbuf_release(&sb_repo);
strbuf_release(&sb_git);
return ret;
}
static int add(int ac, const char **av, const char *prefix)
{
struct add_opts opts;
const char *new_branch_force = NULL;
const char *path, *branch;
struct option options[] = {
OPT__FORCE(&opts.force, N_("checkout <branch> even if already checked out in other worktree")),
OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
N_("create a new branch")),
OPT_STRING('B', NULL, &new_branch_force, N_("branch"),
N_("create or reset a branch")),
OPT_BOOL(0, "detach", &opts.detach, N_("detach HEAD at named commit")),
OPT_END()
};
memset(&opts, 0, sizeof(opts));
ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
if (!!opts.detach + !!opts.new_branch + !!new_branch_force > 1)
die(_("-b, -B, and --detach are mutually exclusive"));
if (ac < 1 || ac > 2)
usage_with_options(worktree_usage, options);
path = prefix ? prefix_filename(prefix, strlen(prefix), av[0]) : av[0];
branch = ac < 2 ? "HEAD" : av[1];
opts.force_new_branch = !!new_branch_force;
if (opts.force_new_branch)
opts.new_branch = new_branch_force;
if (ac < 2 && !opts.new_branch && !opts.detach) {
int n;
const char *s = worktree_basename(path, &n);
opts.new_branch = xstrndup(s, n);
}
if (opts.new_branch) {
struct child_process cp;
memset(&cp, 0, sizeof(cp));
cp.git_cmd = 1;
argv_array_push(&cp.args, "branch");
if (opts.force_new_branch)
argv_array_push(&cp.args, "--force");
argv_array_push(&cp.args, opts.new_branch);
argv_array_push(&cp.args, branch);
if (run_command(&cp))
return -1;
branch = opts.new_branch;
}
return add_worktree(path, branch, &opts);
}
static void show_worktree_porcelain(struct worktree *wt)
{
printf("worktree %s\n", wt->path);
if (wt->is_bare)
printf("bare\n");
else {
printf("HEAD %s\n", sha1_to_hex(wt->head_sha1));
if (wt->is_detached)
printf("detached\n");
else
printf("branch %s\n", wt->head_ref);
}
printf("\n");
}
static void show_worktree(struct worktree *wt, int path_maxlen, int abbrev_len)
{
struct strbuf sb = STRBUF_INIT;
int cur_path_len = strlen(wt->path);
int path_adj = cur_path_len - utf8_strwidth(wt->path);
strbuf_addf(&sb, "%-*s ", 1 + path_maxlen + path_adj, wt->path);
if (wt->is_bare)
strbuf_addstr(&sb, "(bare)");
else {
strbuf_addf(&sb, "%-*s ", abbrev_len,
find_unique_abbrev(wt->head_sha1, DEFAULT_ABBREV));
if (!wt->is_detached)
strbuf_addf(&sb, "[%s]", shorten_unambiguous_ref(wt->head_ref, 0));
else
strbuf_addstr(&sb, "(detached HEAD)");
}
printf("%s\n", sb.buf);
strbuf_release(&sb);
}
static void measure_widths(struct worktree **wt, int *abbrev, int *maxlen)
{
int i;
for (i = 0; wt[i]; i++) {
int sha1_len;
int path_len = strlen(wt[i]->path);
if (path_len > *maxlen)
*maxlen = path_len;
sha1_len = strlen(find_unique_abbrev(wt[i]->head_sha1, *abbrev));
if (sha1_len > *abbrev)
*abbrev = sha1_len;
}
}
static int list(int ac, const char **av, const char *prefix)
{
int porcelain = 0;
struct option options[] = {
OPT_BOOL(0, "porcelain", &porcelain, N_("machine-readable output")),
OPT_END()
};
ac = parse_options(ac, av, prefix, options, worktree_usage, 0);
if (ac)
usage_with_options(worktree_usage, options);
else {
struct worktree **worktrees = get_worktrees();
int path_maxlen = 0, abbrev = DEFAULT_ABBREV, i;
if (!porcelain)
measure_widths(worktrees, &abbrev, &path_maxlen);
for (i = 0; worktrees[i]; i++) {
if (porcelain)
show_worktree_porcelain(worktrees[i]);
else
show_worktree(worktrees[i], path_maxlen, abbrev);
}
free_worktrees(worktrees);
}
return 0;
}
int cmd_worktree(int ac, const char **av, const char *prefix)
{
struct option options[] = {
OPT_END()
};
if (ac < 2)
usage_with_options(worktree_usage, options);
if (!strcmp(av[1], "add"))
return add(ac - 1, av + 1, prefix);
if (!strcmp(av[1], "prune"))
return prune(ac - 1, av + 1, prefix);
if (!strcmp(av[1], "list"))
return list(ac - 1, av + 1, prefix);
usage_with_options(worktree_usage, options);
}