path.c 29.4 KB
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/*
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 * Utilities for paths and pathnames
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 */
#include "cache.h"
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#include "strbuf.h"
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#include "string-list.h"
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#include "dir.h"
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#include "worktree.h"
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static int get_st_mode_bits(const char *path, int *mode)
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{
	struct stat st;
	if (lstat(path, &st) < 0)
		return -1;
	*mode = st.st_mode;
	return 0;
}

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static char bad_path[] = "/bad-path/";

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static struct strbuf *get_pathname(void)
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{
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	static struct strbuf pathname_array[4] = {
		STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
	};
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	static int index;
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	struct strbuf *sb = &pathname_array[3 & ++index];
	strbuf_reset(sb);
	return sb;
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}

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static char *cleanup_path(char *path)
{
	/* Clean it up */
	if (!memcmp(path, "./", 2)) {
		path += 2;
		while (*path == '/')
			path++;
	}
	return path;
}

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static void strbuf_cleanup_path(struct strbuf *sb)
{
	char *path = cleanup_path(sb->buf);
	if (path > sb->buf)
		strbuf_remove(sb, 0, path - sb->buf);
}

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char *mksnpath(char *buf, size_t n, const char *fmt, ...)
{
	va_list args;
	unsigned len;

	va_start(args, fmt);
	len = vsnprintf(buf, n, fmt, args);
	va_end(args);
	if (len >= n) {
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		strlcpy(buf, bad_path, n);
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		return buf;
	}
	return cleanup_path(buf);
}

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static int dir_prefix(const char *buf, const char *dir)
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{
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	int len = strlen(dir);
	return !strncmp(buf, dir, len) &&
		(is_dir_sep(buf[len]) || buf[len] == '\0');
}
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/* $buf =~ m|$dir/+$file| but without regex */
static int is_dir_file(const char *buf, const char *dir, const char *file)
{
	int len = strlen(dir);
	if (strncmp(buf, dir, len) || !is_dir_sep(buf[len]))
		return 0;
	while (is_dir_sep(buf[len]))
		len++;
	return !strcmp(buf + len, file);
}

static void replace_dir(struct strbuf *buf, int len, const char *newdir)
{
	int newlen = strlen(newdir);
	int need_sep = (buf->buf[len] && !is_dir_sep(buf->buf[len])) &&
		!is_dir_sep(newdir[newlen - 1]);
	if (need_sep)
		len--;	 /* keep one char, to be replaced with '/'  */
	strbuf_splice(buf, 0, len, newdir, newlen);
	if (need_sep)
		buf->buf[newlen] = '/';
}

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struct common_dir {
	/* Not considered garbage for report_linked_checkout_garbage */
	unsigned ignore_garbage:1;
	unsigned is_dir:1;
	/* Not common even though its parent is */
	unsigned exclude:1;
	const char *dirname;
};

static struct common_dir common_list[] = {
	{ 0, 1, 0, "branches" },
	{ 0, 1, 0, "hooks" },
	{ 0, 1, 0, "info" },
	{ 0, 0, 1, "info/sparse-checkout" },
	{ 1, 1, 0, "logs" },
	{ 1, 1, 1, "logs/HEAD" },
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	{ 0, 1, 1, "logs/refs/bisect" },
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	{ 0, 1, 0, "lost-found" },
	{ 0, 1, 0, "objects" },
	{ 0, 1, 0, "refs" },
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	{ 0, 1, 1, "refs/bisect" },
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	{ 0, 1, 0, "remotes" },
	{ 0, 1, 0, "worktrees" },
	{ 0, 1, 0, "rr-cache" },
	{ 0, 1, 0, "svn" },
	{ 0, 0, 0, "config" },
	{ 1, 0, 0, "gc.pid" },
	{ 0, 0, 0, "packed-refs" },
	{ 0, 0, 0, "shallow" },
	{ 0, 0, 0, NULL }
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};

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/*
 * A compressed trie.  A trie node consists of zero or more characters that
 * are common to all elements with this prefix, optionally followed by some
 * children.  If value is not NULL, the trie node is a terminal node.
 *
 * For example, consider the following set of strings:
 * abc
 * def
 * definite
 * definition
 *
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 * The trie would look like:
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 * root: len = 0, children a and d non-NULL, value = NULL.
 *    a: len = 2, contents = bc, value = (data for "abc")
 *    d: len = 2, contents = ef, children i non-NULL, value = (data for "def")
 *       i: len = 3, contents = nit, children e and i non-NULL, value = NULL
 *           e: len = 0, children all NULL, value = (data for "definite")
 *           i: len = 2, contents = on, children all NULL,
 *              value = (data for "definition")
 */
struct trie {
	struct trie *children[256];
	int len;
	char *contents;
	void *value;
};

static struct trie *make_trie_node(const char *key, void *value)
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{
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	struct trie *new_node = xcalloc(1, sizeof(*new_node));
	new_node->len = strlen(key);
	if (new_node->len) {
		new_node->contents = xmalloc(new_node->len);
		memcpy(new_node->contents, key, new_node->len);
	}
	new_node->value = value;
	return new_node;
}
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/*
 * Add a key/value pair to a trie.  The key is assumed to be \0-terminated.
 * If there was an existing value for this key, return it.
 */
static void *add_to_trie(struct trie *root, const char *key, void *value)
{
	struct trie *child;
	void *old;
	int i;

	if (!*key) {
		/* we have reached the end of the key */
		old = root->value;
		root->value = value;
		return old;
	}

	for (i = 0; i < root->len; i++) {
		if (root->contents[i] == key[i])
			continue;

		/*
		 * Split this node: child will contain this node's
		 * existing children.
		 */
		child = malloc(sizeof(*child));
		memcpy(child->children, root->children, sizeof(root->children));

		child->len = root->len - i - 1;
		if (child->len) {
			child->contents = xstrndup(root->contents + i + 1,
						   child->len);
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		}
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		child->value = root->value;
		root->value = NULL;
		root->len = i;

		memset(root->children, 0, sizeof(root->children));
		root->children[(unsigned char)root->contents[i]] = child;

		/* This is the newly-added child. */
		root->children[(unsigned char)key[i]] =
			make_trie_node(key + i + 1, value);
		return NULL;
	}

	/* We have matched the entire compressed section */
	if (key[i]) {
		child = root->children[(unsigned char)key[root->len]];
		if (child) {
			return add_to_trie(child, key + root->len + 1, value);
		} else {
			child = make_trie_node(key + root->len + 1, value);
			root->children[(unsigned char)key[root->len]] = child;
			return NULL;
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		}
	}
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	old = root->value;
	root->value = value;
	return old;
}

typedef int (*match_fn)(const char *unmatched, void *data, void *baton);

/*
 * Search a trie for some key.  Find the longest /-or-\0-terminated
 * prefix of the key for which the trie contains a value.  Call fn
 * with the unmatched portion of the key and the found value, and
 * return its return value.  If there is no such prefix, return -1.
 *
 * The key is partially normalized: consecutive slashes are skipped.
 *
 * For example, consider the trie containing only [refs,
 * refs/worktree] (both with values).
 *
 * | key             | unmatched  | val from node | return value |
 * |-----------------|------------|---------------|--------------|
 * | a               | not called | n/a           | -1           |
 * | refs            | \0         | refs          | as per fn    |
 * | refs/           | /          | refs          | as per fn    |
 * | refs/w          | /w         | refs          | as per fn    |
 * | refs/worktree   | \0         | refs/worktree | as per fn    |
 * | refs/worktree/  | /          | refs/worktree | as per fn    |
 * | refs/worktree/a | /a         | refs/worktree | as per fn    |
 * |-----------------|------------|---------------|--------------|
 *
 */
static int trie_find(struct trie *root, const char *key, match_fn fn,
		     void *baton)
{
	int i;
	int result;
	struct trie *child;

	if (!*key) {
		/* we have reached the end of the key */
		if (root->value && !root->len)
			return fn(key, root->value, baton);
		else
			return -1;
	}

	for (i = 0; i < root->len; i++) {
		/* Partial path normalization: skip consecutive slashes. */
		if (key[i] == '/' && key[i+1] == '/') {
			key++;
			continue;
		}
		if (root->contents[i] != key[i])
			return -1;
	}

	/* Matched the entire compressed section */
	key += i;
	if (!*key)
		/* End of key */
		return fn(key, root->value, baton);

	/* Partial path normalization: skip consecutive slashes */
	while (key[0] == '/' && key[1] == '/')
		key++;

	child = root->children[(unsigned char)*key];
	if (child)
		result = trie_find(child, key + 1, fn, baton);
	else
		result = -1;

	if (result >= 0 || (*key != '/' && *key != 0))
		return result;
	if (root->value)
		return fn(key, root->value, baton);
	else
		return -1;
}

static struct trie common_trie;
static int common_trie_done_setup;

static void init_common_trie(void)
{
	struct common_dir *p;

	if (common_trie_done_setup)
		return;

	for (p = common_list; p->dirname; p++)
		add_to_trie(&common_trie, p->dirname, p);

	common_trie_done_setup = 1;
}

/*
 * Helper function for update_common_dir: returns 1 if the dir
 * prefix is common.
 */
static int check_common(const char *unmatched, void *value, void *baton)
{
	struct common_dir *dir = value;

	if (!dir)
		return 0;

	if (dir->is_dir && (unmatched[0] == 0 || unmatched[0] == '/'))
		return !dir->exclude;

	if (!dir->is_dir && unmatched[0] == 0)
		return !dir->exclude;

	return 0;
}

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static void update_common_dir(struct strbuf *buf, int git_dir_len,
			      const char *common_dir)
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{
	char *base = buf->buf + git_dir_len;
	init_common_trie();
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	if (!common_dir)
		common_dir = get_git_common_dir();
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	if (trie_find(&common_trie, base, check_common, NULL) > 0)
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		replace_dir(buf, git_dir_len, common_dir);
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}

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void report_linked_checkout_garbage(void)
{
	struct strbuf sb = STRBUF_INIT;
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	const struct common_dir *p;
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	int len;

	if (!git_common_dir_env)
		return;
	strbuf_addf(&sb, "%s/", get_git_dir());
	len = sb.len;
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	for (p = common_list; p->dirname; p++) {
		const char *path = p->dirname;
		if (p->ignore_garbage)
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			continue;
		strbuf_setlen(&sb, len);
		strbuf_addstr(&sb, path);
		if (file_exists(sb.buf))
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			report_garbage(PACKDIR_FILE_GARBAGE, sb.buf);
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	}
	strbuf_release(&sb);
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}

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static void adjust_git_path(struct strbuf *buf, int git_dir_len)
{
	const char *base = buf->buf + git_dir_len;
	if (git_graft_env && is_dir_file(base, "info", "grafts"))
		strbuf_splice(buf, 0, buf->len,
			      get_graft_file(), strlen(get_graft_file()));
	else if (git_index_env && !strcmp(base, "index"))
		strbuf_splice(buf, 0, buf->len,
			      get_index_file(), strlen(get_index_file()));
	else if (git_db_env && dir_prefix(base, "objects"))
		replace_dir(buf, git_dir_len + 7, get_object_directory());
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	else if (git_common_dir_env)
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		update_common_dir(buf, git_dir_len, NULL);
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}

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static void do_git_path(const struct worktree *wt, struct strbuf *buf,
			const char *fmt, va_list args)
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{
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	int gitdir_len;
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	strbuf_addstr(buf, get_worktree_git_dir(wt));
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	if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
		strbuf_addch(buf, '/');
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	gitdir_len = buf->len;
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	strbuf_vaddf(buf, fmt, args);
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	adjust_git_path(buf, gitdir_len);
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	strbuf_cleanup_path(buf);
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}

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char *git_path_buf(struct strbuf *buf, const char *fmt, ...)
{
	va_list args;
	strbuf_reset(buf);
	va_start(args, fmt);
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	do_git_path(NULL, buf, fmt, args);
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	va_end(args);
	return buf->buf;
}

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void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
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{
	va_list args;
	va_start(args, fmt);
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	do_git_path(NULL, sb, fmt, args);
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	va_end(args);
}

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const char *git_path(const char *fmt, ...)
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{
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	struct strbuf *pathname = get_pathname();
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	va_list args;
	va_start(args, fmt);
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	do_git_path(NULL, pathname, fmt, args);
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	va_end(args);
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	return pathname->buf;
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}

char *git_pathdup(const char *fmt, ...)
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{
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	struct strbuf path = STRBUF_INIT;
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	va_list args;
	va_start(args, fmt);
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	do_git_path(NULL, &path, fmt, args);
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	va_end(args);
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	return strbuf_detach(&path, NULL);
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}

char *mkpathdup(const char *fmt, ...)
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{
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	struct strbuf sb = STRBUF_INIT;
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	va_list args;
	va_start(args, fmt);
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	strbuf_vaddf(&sb, fmt, args);
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	va_end(args);
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	strbuf_cleanup_path(&sb);
	return strbuf_detach(&sb, NULL);
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}

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const char *mkpath(const char *fmt, ...)
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{
	va_list args;
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	struct strbuf *pathname = get_pathname();
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	va_start(args, fmt);
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	strbuf_vaddf(pathname, fmt, args);
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	va_end(args);
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	return cleanup_path(pathname->buf);
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}
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const char *worktree_git_path(const struct worktree *wt, const char *fmt, ...)
{
	struct strbuf *pathname = get_pathname();
	va_list args;
	va_start(args, fmt);
	do_git_path(wt, pathname, fmt, args);
	va_end(args);
	return pathname->buf;
}

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static void do_submodule_path(struct strbuf *buf, const char *path,
			      const char *fmt, va_list args)
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{
	const char *git_dir;
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	struct strbuf git_submodule_common_dir = STRBUF_INIT;
	struct strbuf git_submodule_dir = STRBUF_INIT;
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	strbuf_addstr(buf, path);
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	strbuf_complete(buf, '/');
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	strbuf_addstr(buf, ".git");
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	git_dir = read_gitfile(buf->buf);
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	if (git_dir) {
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		strbuf_reset(buf);
		strbuf_addstr(buf, git_dir);
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	}
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	strbuf_addch(buf, '/');
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	strbuf_addbuf(&git_submodule_dir, buf);
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	strbuf_vaddf(buf, fmt, args);
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	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
		update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);

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	strbuf_cleanup_path(buf);
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	strbuf_release(&git_submodule_dir);
	strbuf_release(&git_submodule_common_dir);
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}

char *git_pathdup_submodule(const char *path, const char *fmt, ...)
{
	va_list args;
	struct strbuf buf = STRBUF_INIT;
	va_start(args, fmt);
	do_submodule_path(&buf, path, fmt, args);
	va_end(args);
	return strbuf_detach(&buf, NULL);
}

void strbuf_git_path_submodule(struct strbuf *buf, const char *path,
			       const char *fmt, ...)
{
	va_list args;
	va_start(args, fmt);
	do_submodule_path(buf, path, fmt, args);
	va_end(args);
}

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static void do_git_common_path(struct strbuf *buf,
			       const char *fmt,
			       va_list args)
{
	strbuf_addstr(buf, get_git_common_dir());
	if (buf->len && !is_dir_sep(buf->buf[buf->len - 1]))
		strbuf_addch(buf, '/');
	strbuf_vaddf(buf, fmt, args);
	strbuf_cleanup_path(buf);
}

const char *git_common_path(const char *fmt, ...)
{
	struct strbuf *pathname = get_pathname();
	va_list args;
	va_start(args, fmt);
	do_git_common_path(pathname, fmt, args);
	va_end(args);
	return pathname->buf;
}

void strbuf_git_common_path(struct strbuf *sb, const char *fmt, ...)
{
	va_list args;
	va_start(args, fmt);
	do_git_common_path(sb, fmt, args);
	va_end(args);
}

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int validate_headref(const char *path)
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{
	struct stat st;
	char *buf, buffer[256];
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	unsigned char sha1[20];
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	int fd;
	ssize_t len;
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	if (lstat(path, &st) < 0)
		return -1;

	/* Make sure it is a "refs/.." symlink */
	if (S_ISLNK(st.st_mode)) {
		len = readlink(path, buffer, sizeof(buffer)-1);
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		if (len >= 5 && !memcmp("refs/", buffer, 5))
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			return 0;
		return -1;
	}

	/*
	 * Anything else, just open it and try to see if it is a symbolic ref.
	 */
	fd = open(path, O_RDONLY);
	if (fd < 0)
		return -1;
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	len = read_in_full(fd, buffer, sizeof(buffer)-1);
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	close(fd);

	/*
	 * Is it a symbolic ref?
	 */
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	if (len < 4)
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		return -1;
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	if (!memcmp("ref:", buffer, 4)) {
		buf = buffer + 4;
		len -= 4;
		while (len && isspace(*buf))
			buf++, len--;
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		if (len >= 5 && !memcmp("refs/", buf, 5))
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			return 0;
	}

	/*
	 * Is this a detached HEAD?
	 */
	if (!get_sha1_hex(buffer, sha1))
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		return 0;
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	return -1;
}

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static struct passwd *getpw_str(const char *username, size_t len)
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{
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	struct passwd *pw;
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	char *username_z = xmemdupz(username, len);
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	pw = getpwnam(username_z);
	free(username_z);
	return pw;
}
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/*
 * Return a string with ~ and ~user expanded via getpw*.  If buf != NULL,
 * then it is a newly allocated string. Returns NULL on getpw failure or
 * if path is NULL.
 */
char *expand_user_path(const char *path)
{
	struct strbuf user_path = STRBUF_INIT;
	const char *to_copy = path;

	if (path == NULL)
		goto return_null;
	if (path[0] == '~') {
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		const char *first_slash = strchrnul(path, '/');
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		const char *username = path + 1;
		size_t username_len = first_slash - username;
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		if (username_len == 0) {
			const char *home = getenv("HOME");
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			if (!home)
				goto return_null;
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			strbuf_addstr(&user_path, home);
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#ifdef GIT_WINDOWS_NATIVE
			convert_slashes(user_path.buf);
#endif
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		} else {
			struct passwd *pw = getpw_str(username, username_len);
			if (!pw)
				goto return_null;
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			strbuf_addstr(&user_path, pw->pw_dir);
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		}
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		to_copy = first_slash;
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	}
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	strbuf_addstr(&user_path, to_copy);
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	return strbuf_detach(&user_path, NULL);
return_null:
	strbuf_release(&user_path);
	return NULL;
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}

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/*
 * First, one directory to try is determined by the following algorithm.
 *
 * (0) If "strict" is given, the path is used as given and no DWIM is
 *     done. Otherwise:
 * (1) "~/path" to mean path under the running user's home directory;
 * (2) "~user/path" to mean path under named user's home directory;
 * (3) "relative/path" to mean cwd relative directory; or
 * (4) "/absolute/path" to mean absolute directory.
 *
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 * Unless "strict" is given, we check "%s/.git", "%s", "%s.git/.git", "%s.git"
 * in this order. We select the first one that is a valid git repository, and
 * chdir() to it. If none match, or we fail to chdir, we return NULL.
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 *
 * If all goes well, we return the directory we used to chdir() (but
 * before ~user is expanded), avoiding getcwd() resolving symbolic
 * links.  User relative paths are also returned as they are given,
 * except DWIM suffixing.
 */
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const char *enter_repo(const char *path, int strict)
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{
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	static struct strbuf validated_path = STRBUF_INIT;
	static struct strbuf used_path = STRBUF_INIT;
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	if (!path)
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		return NULL;

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	if (!strict) {
		static const char *suffix[] = {
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			"/.git", "", ".git/.git", ".git", NULL,
676
		};
677
		const char *gitfile;
678 679
		int len = strlen(path);
		int i;
680
		while ((1 < len) && (path[len-1] == '/'))
681
			len--;
682

683 684 685 686
		/*
		 * We can handle arbitrary-sized buffers, but this remains as a
		 * sanity check on untrusted input.
		 */
687
		if (PATH_MAX <= len)
688
			return NULL;
689

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		strbuf_reset(&used_path);
		strbuf_reset(&validated_path);
		strbuf_add(&used_path, path, len);
		strbuf_add(&validated_path, path, len);

		if (used_path.buf[0] == '~') {
			char *newpath = expand_user_path(used_path.buf);
			if (!newpath)
698
				return NULL;
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			strbuf_attach(&used_path, newpath, strlen(newpath),
				      strlen(newpath));
701 702
		}
		for (i = 0; suffix[i]; i++) {
703
			struct stat st;
704 705 706
			size_t baselen = used_path.len;
			strbuf_addstr(&used_path, suffix[i]);
			if (!stat(used_path.buf, &st) &&
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			    (S_ISREG(st.st_mode) ||
708 709
			    (S_ISDIR(st.st_mode) && is_git_directory(used_path.buf)))) {
				strbuf_addstr(&validated_path, suffix[i]);
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				break;
			}
712
			strbuf_setlen(&used_path, baselen);
713
		}
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		if (!suffix[i])
			return NULL;
716
		gitfile = read_gitfile(used_path.buf);
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		if (gitfile) {
			strbuf_reset(&used_path);
			strbuf_addstr(&used_path, gitfile);
		}
		if (chdir(used_path.buf))
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			return NULL;
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		path = validated_path.buf;
724
	}
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	else {
		const char *gitfile = read_gitfile(path);
		if (gitfile)
			path = gitfile;
		if (chdir(path))
			return NULL;
	}
732

733
	if (is_git_directory(".")) {
René Scharfe's avatar
René Scharfe committed
734
		set_git_dir(".");
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		check_repository_format();
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		return path;
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	}

	return NULL;
}
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742
static int calc_shared_perm(int mode)
743
{
744
	int tweak;
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	if (get_shared_repository() < 0)
		tweak = -get_shared_repository();
748
	else
749
		tweak = get_shared_repository();
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	if (!(mode & S_IWUSR))
		tweak &= ~0222;
	if (mode & S_IXUSR)
		/* Copy read bits to execute bits */
		tweak |= (tweak & 0444) >> 2;
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	if (get_shared_repository() < 0)
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		mode = (mode & ~0777) | tweak;
	else
759
		mode |= tweak;
760

761 762 763 764 765 766 767 768
	return mode;
}


int adjust_shared_perm(const char *path)
{
	int old_mode, new_mode;

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	if (!get_shared_repository())
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		return 0;
	if (get_st_mode_bits(path, &old_mode) < 0)
		return -1;

	new_mode = calc_shared_perm(old_mode);
	if (S_ISDIR(old_mode)) {
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		/* Copy read bits to execute bits */
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		new_mode |= (new_mode & 0444) >> 2;
		new_mode |= FORCE_DIR_SET_GID;
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	}

781 782
	if (((old_mode ^ new_mode) & ~S_IFMT) &&
			chmod(path, (new_mode & ~S_IFMT)) < 0)
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		return -2;
	return 0;
}
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787 788 789 790 791 792 793 794 795 796 797 798
void safe_create_dir(const char *dir, int share)
{
	if (mkdir(dir, 0777) < 0) {
		if (errno != EEXIST) {
			perror(dir);
			exit(1);
		}
	}
	else if (share && adjust_shared_perm(dir))
		die(_("Could not make %s writable by group"), dir);
}

799 800 801 802 803 804 805 806 807 808
static int have_same_root(const char *path1, const char *path2)
{
	int is_abs1, is_abs2;

	is_abs1 = is_absolute_path(path1);
	is_abs2 = is_absolute_path(path2);
	return (is_abs1 && is_abs2 && tolower(path1[0]) == tolower(path2[0])) ||
	       (!is_abs1 && !is_abs2);
}

809 810 811 812 813 814 815 816
/*
 * Give path as relative to prefix.
 *
 * The strbuf may or may not be used, so do not assume it contains the
 * returned path.
 */
const char *relative_path(const char *in, const char *prefix,
			  struct strbuf *sb)
817
{
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	int in_len = in ? strlen(in) : 0;
	int prefix_len = prefix ? strlen(prefix) : 0;
	int in_off = 0;
	int prefix_off = 0;
822 823
	int i = 0, j = 0;

824 825 826 827 828
	if (!in_len)
		return "./";
	else if (!prefix_len)
		return in;

829
	if (have_same_root(in, prefix))
830
		/* bypass dos_drive, for "c:" is identical to "C:" */
831 832
		i = j = has_dos_drive_prefix(in);
	else {
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		return in;
	}

836 837 838
	while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
		if (is_dir_sep(prefix[i])) {
			while (is_dir_sep(prefix[i]))
839
				i++;
840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863
			while (is_dir_sep(in[j]))
				j++;
			prefix_off = i;
			in_off = j;
		} else {
			i++;
			j++;
		}
	}

	if (
	    /* "prefix" seems like prefix of "in" */
	    i >= prefix_len &&
	    /*
	     * but "/foo" is not a prefix of "/foobar"
	     * (i.e. prefix not end with '/')
	     */
	    prefix_off < prefix_len) {
		if (j >= in_len) {
			/* in="/a/b", prefix="/a/b" */
			in_off = in_len;
		} else if (is_dir_sep(in[j])) {
			/* in="/a/b/c", prefix="/a/b" */
			while (is_dir_sep(in[j]))
864
				j++;
865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899
			in_off = j;
		} else {
			/* in="/a/bbb/c", prefix="/a/b" */
			i = prefix_off;
		}
	} else if (
		   /* "in" is short than "prefix" */
		   j >= in_len &&
		   /* "in" not end with '/' */
		   in_off < in_len) {
		if (is_dir_sep(prefix[i])) {
			/* in="/a/b", prefix="/a/b/c/" */
			while (is_dir_sep(prefix[i]))
				i++;
			in_off = in_len;
		}
	}
	in += in_off;
	in_len -= in_off;

	if (i >= prefix_len) {
		if (!in_len)
			return "./";
		else
			return in;
	}

	strbuf_reset(sb);
	strbuf_grow(sb, in_len);

	while (i < prefix_len) {
		if (is_dir_sep(prefix[i])) {
			strbuf_addstr(sb, "../");
			while (is_dir_sep(prefix[i]))
				i++;
900 901 902 903
			continue;
		}
		i++;
	}
904 905 906 907 908 909
	if (!is_dir_sep(prefix[prefix_len - 1]))
		strbuf_addstr(sb, "../");

	strbuf_addstr(sb, in);

	return sb->buf;
910
}
911

912 913 914 915 916 917 918 919 920
/*
 * A simpler implementation of relative_path
 *
 * Get relative path by removing "prefix" from "in". This function
 * first appears in v1.5.6-1-g044bbbc, and makes git_dir shorter
 * to increase performance when traversing the path to work_tree.
 */
const char *remove_leading_path(const char *in, const char *prefix)
{
921
	static struct strbuf buf = STRBUF_INIT;
922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949
	int i = 0, j = 0;

	if (!prefix || !prefix[0])
		return in;
	while (prefix[i]) {
		if (is_dir_sep(prefix[i])) {
			if (!is_dir_sep(in[j]))
				return in;
			while (is_dir_sep(prefix[i]))
				i++;
			while (is_dir_sep(in[j]))
				j++;
			continue;
		} else if (in[j] != prefix[i]) {
			return in;
		}
		i++;
		j++;
	}
	if (
	    /* "/foo" is a prefix of "/foo" */
	    in[j] &&
	    /* "/foo" is not a prefix of "/foobar" */
	    !is_dir_sep(prefix[i-1]) && !is_dir_sep(in[j])
	   )
		return in;
	while (is_dir_sep(in[j]))
		j++;
950 951

	strbuf_reset(&buf);
952
	if (!in[j])
953
		strbuf_addstr(&buf, ".");
954
	else
955 956
		strbuf_addstr(&buf, in + j);
	return buf.buf;
957 958
}

959
/*
960
 * It is okay if dst == src, but they should not overlap otherwise.
961
 *
962 963 964
 * Performs the following normalizations on src, storing the result in dst:
 * - Ensures that components are separated by '/' (Windows only)
 * - Squashes sequences of '/'.
965 966
 * - Removes "." components.
 * - Removes ".." components, and the components the precede them.
967 968
 * Returns failure (non-zero) if a ".." component appears as first path
 * component anytime during the normalization. Otherwise, returns success (0).
969 970 971
 *
 * Note that this function is purely textual.  It does not follow symlinks,
 * verify the existence of the path, or make any system calls.
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 *
 * prefix_len != NULL is for a specific case of prefix_pathspec():
 * assume that src == dst and src[0..prefix_len-1] is already
 * normalized, any time "../" eats up to the prefix_len part,
 * prefix_len is reduced. In the end prefix_len is the remaining
 * prefix that has not been overridden by user pathspec.
978 979 980 981 982
 *
 * NEEDSWORK: This function doesn't perform normalization w.r.t. trailing '/'.
 * For everything but the root folder itself, the normalized path should not
 * end with a '/', then the callers need to be fixed up accordingly.
 *
983
 */
984
int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
985
{
986
	char *dst0;
987
	int i;
988

989
	for (i = has_dos_drive_prefix(src); i > 0; i--)
990 991
		*dst++ = *src++;
	dst0 = dst;
992

993
	if (is_dir_sep(*src)) {
994
		*dst++ = '/';
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033
		while (is_dir_sep(*src))
			src++;
	}

	for (;;) {
		char c = *src;

		/*
		 * A path component that begins with . could be
		 * special:
		 * (1) "." and ends   -- ignore and terminate.
		 * (2) "./"           -- ignore them, eat slash and continue.
		 * (3) ".." and ends  -- strip one and terminate.
		 * (4) "../"          -- strip one, eat slash and continue.
		 */
		if (c == '.') {
			if (!src[1]) {
				/* (1) */
				src++;
			} else if (is_dir_sep(src[1])) {
				/* (2) */
				src += 2;
				while (is_dir_sep(*src))
					src++;
				continue;
			} else if (src[1] == '.') {
				if (!src[2]) {
					/* (3) */
					src += 2;
					goto up_one;
				} else if (is_dir_sep(src[2])) {
					/* (4) */
					src += 3;
					while (is_dir_sep(*src))
						src++;
					goto up_one;
				}
			}
		}
1034

1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
		/* copy up to the next '/', and eat all '/' */
		while ((c = *src++) != '\0' && !is_dir_sep(c))
			*dst++ = c;
		if (is_dir_sep(c)) {
			*dst++ = '/';
			while (is_dir_sep(c))
				c = *src++;
			src--;
		} else if (!c)
			break;
		continue;

	up_one:
		/*
		 * dst0..dst is prefix portion, and dst[-1] is '/';
		 * go up one level.
		 */
1052 1053
		dst--;	/* go to trailing '/' */
		if (dst <= dst0)
1054
			return -1;
1055 1056 1057
		/* Windows: dst[-1] cannot be backslash anymore */
		while (dst0 < dst && dst[-1] != '/')
			dst--;
1058 1059
		if (prefix_len && *prefix_len > dst - dst0)
			*prefix_len = dst - dst0;
1060
	}
1061
	*dst = '\0';
1062
	return 0;
1063
}
1064

1065 1066 1067 1068 1069
int normalize_path_copy(char *dst, const char *src)
{
	return normalize_path_copy_len(dst, src, NULL);
}

1070 1071
/*
 * path = Canonical absolute path
1072 1073
 * prefixes = string_list containing normalized, absolute paths without
 * trailing slashes (except for the root directory, which is denoted by "/").
1074
 *
1075
 * Determines, for each path in prefixes, whether the "prefix"
1076 1077
 * is an ancestor directory of path.  Returns the length of the longest
 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
1078 1079
 * is an ancestor.  (Note that this means 0 is returned if prefixes is
 * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
1080 1081
 * are not considered to be their own ancestors.  path must be in a
 * canonical form: empty components, or "." or ".." components are not
1082
 * allowed.
1083
 */
1084
int longest_ancestor_length(const char *path, struct string_list *prefixes)
1085
{
1086
	int i, max_len = -1;
1087

1088
	if (!strcmp(path, "/"))
1089 1090
		return -1;

1091 1092
	for (i = 0; i < prefixes->nr; i++) {
		const char *ceil = prefixes->items[i].string;
1093 1094
		int len = strlen(ceil);

1095 1096 1097 1098 1099 1100
		if (len == 1 && ceil[0] == '/')
			len = 0; /* root matches anything, with length 0 */
		else if (!strncmp(path, ceil, len) && path[len] == '/')
			; /* match of length len */
		else
			continue; /* no match */
1101

1102
		if (len > max_len)
1103 1104 1105 1106 1107
			max_len = len;
	}

	return max_len;
}
1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143

/* strip arbitrary amount of directory separators at end of path */
static inline int chomp_trailing_dir_sep(const char *path, int len)
{
	while (len && is_dir_sep(path[len - 1]))
		len--;
	return len;
}

/*
 * If path ends with suffix (complete path components), returns the
 * part before suffix (sans trailing directory separators).
 * Otherwise returns NULL.
 */
char *strip_path_suffix(const char *path, const char *suffix)
{
	int path_len = strlen(path), suffix_len = strlen(suffix);

	while (suffix_len) {
		if (!path_len)
			return NULL;

		if (is_dir_sep(path[path_len - 1])) {
			if (!is_dir_sep(suffix[suffix_len - 1]))
				return NULL;
			path_len = chomp_trailing_dir_sep(path, path_len);
			suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
		}
		else if (path[--path_len] != suffix[--suffix_len])
			return NULL;
	}

	if (path_len && !is_dir_sep(path[path_len - 1]))
		return NULL;
	return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
}
1144 1145 1146 1147 1148 1149 1150 1151

int daemon_avoid_alias(const char *p)
{
	int sl, ndot;

	/*
	 * This resurrects the belts and suspenders paranoia check by HPA
	 * done in <[email protected]> thread, now enter_repo()
1152
	 * does not do getcwd() based path canonicalization.
1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190
	 *
	 * sl becomes true immediately after seeing '/' and continues to
	 * be true as long as dots continue after that without intervening
	 * non-dot character.
	 */
	if (!p || (*p != '/' && *p != '~'))
		return -1;
	sl = 1; ndot = 0;
	p++;

	while (1) {
		char ch = *p++;
		if (sl) {
			if (ch == '.')
				ndot++;
			else if (ch == '/') {
				if (ndot < 3)
					/* reject //, /./ and /../ */
					return -1;
				ndot = 0;
			}
			else if (ch == 0) {
				if (0 < ndot && ndot < 3)
					/* reject /.$ and /..$ */
					return -1;
				return 0;
			}
			else
				sl = ndot = 0;
		}
		else if (ch == 0)
			return 0;
		else if (ch == '/') {
			sl = 1;
			ndot = 0;
		}
	}
}
1191

1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223
static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
{
	if (len < skip)
		return 0;
	len -= skip;
	path += skip;
	while (len-- > 0) {
		char c = *(path++);
		if (c != ' ' && c != '.')
			return 0;
	}
	return 1;
}

int is_ntfs_dotgit(const char *name)
{
	int len;

	for (len = 0; ; len++)
		if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
			if (only_spaces_and_periods(name, len, 4) &&
					!strncasecmp(name, ".git", 4))
				return 1;
			if (only_spaces_and_periods(name, len, 5) &&
					!strncasecmp(name, "git~1", 5))
				return 1;
			if (name[len] != '\\')
				return 0;
			name += len + 1;
			len = -1;
		}
}
1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238

char *xdg_config_home(const char *filename)
{
	const char *home, *config_home;

	assert(filename);
	config_home = getenv("XDG_CONFIG_HOME");
	if (config_home && *config_home)
		return mkpathdup("%s/git/%s", config_home, filename);

	home = getenv("HOME");
	if (home)
		return mkpathdup("%s/.config/git/%s", home, filename);
	return NULL;
}
1239 1240 1241 1242 1243 1244 1245 1246 1247 1248

GIT_PATH_FUNC(git_path_cherry_pick_head, "CHERRY_PICK_HEAD")
GIT_PATH_FUNC(git_path_revert_head, "REVERT_HEAD")
GIT_PATH_FUNC(git_path_squash_msg, "SQUASH_MSG")
GIT_PATH_FUNC(git_path_merge_msg, "MERGE_MSG")
GIT_PATH_FUNC(git_path_merge_rr, "MERGE_RR")
GIT_PATH_FUNC(git_path_merge_mode, "MERGE_MODE")
GIT_PATH_FUNC(git_path_merge_head, "MERGE_HEAD")
GIT_PATH_FUNC(git_path_fetch_head, "FETCH_HEAD")
GIT_PATH_FUNC(git_path_shallow, "shallow")