path.c 27.9 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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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
 *
 * The trie would look look like:
 * 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))
			report_garbage("unused in linked checkout", sb.buf);
	}
	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(struct strbuf *buf, const char *fmt, va_list args)
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{
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	int gitdir_len;
	strbuf_addstr(buf, get_git_dir());
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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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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(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(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(&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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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);
	if (buf->len && buf->buf[buf->len - 1] != '/')
		strbuf_addch(buf, '/');
	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_addstr(&git_submodule_dir, buf->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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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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		} 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 char used_path[PATH_MAX];
	static char validated_path[PATH_MAX];

	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,
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		};
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		const char *gitfile;
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		int len = strlen(path);
		int i;
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		while ((1 < len) && (path[len-1] == '/'))
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			len--;
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		if (PATH_MAX <= len)
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			return NULL;
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		strncpy(used_path, path, len); used_path[len] = 0 ;
		strcpy(validated_path, used_path);

		if (used_path[0] == '~') {
			char *newpath = expand_user_path(used_path);
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			if (!newpath || (PATH_MAX - 10 < strlen(newpath))) {
				free(newpath);
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				return NULL;
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			}
			/*
			 * Copy back into the static buffer. A pity
			 * since newpath was not bounded, but other
			 * branches of the if are limited by PATH_MAX
			 * anyway.
			 */
			strcpy(used_path, newpath); free(newpath);
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		}
		else if (PATH_MAX - 10 < len)
			return NULL;
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		len = strlen(used_path);
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		for (i = 0; suffix[i]; i++) {
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			struct stat st;
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			strcpy(used_path + len, suffix[i]);
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			if (!stat(used_path, &st) &&
			    (S_ISREG(st.st_mode) ||
			    (S_ISDIR(st.st_mode) && is_git_directory(used_path)))) {
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				strcat(validated_path, suffix[i]);
				break;
			}
		}
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		if (!suffix[i])
			return NULL;
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		gitfile = read_gitfile(used_path);
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		if (gitfile)
			strcpy(used_path, gitfile);
		if (chdir(used_path))
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			return NULL;
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		path = validated_path;
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	}
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	else {
		const char *gitfile = read_gitfile(path);
		if (gitfile)
			path = gitfile;
		if (chdir(path))
			return NULL;
	}
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	if (is_git_directory(".")) {
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René Scharfe committed
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		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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static int calc_shared_perm(int mode)
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{
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	int tweak;
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	if (shared_repository < 0)
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		tweak = -shared_repository;
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	else
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		tweak = 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;
	if (shared_repository < 0)
		mode = (mode & ~0777) | tweak;
	else
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		mode |= tweak;
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	return mode;
}


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

	if (!shared_repository)
		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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	}

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	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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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);
}

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/*
 * 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)
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{
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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;
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	int i = 0, j = 0;

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	if (!in_len)
		return "./";
	else if (!prefix_len)
		return in;

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	if (have_same_root(in, prefix)) {
		/* bypass dos_drive, for "c:" is identical to "C:" */
		if (has_dos_drive_prefix(in)) {
			i = 2;
			j = 2;
		}
	} else {
		return in;
	}

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	while (i < prefix_len && j < in_len && prefix[i] == in[j]) {
		if (is_dir_sep(prefix[i])) {
			while (is_dir_sep(prefix[i]))
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				i++;
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			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]))
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				j++;
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			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++;
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			continue;
		}
		i++;
	}
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	if (!is_dir_sep(prefix[prefix_len - 1]))
		strbuf_addstr(sb, "../");

	strbuf_addstr(sb, in);

	return sb->buf;
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}
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/*
 * 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)
{
	static char buf[PATH_MAX + 1];
	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++;
	if (!in[j])
		strcpy(buf, ".");
	else
		strcpy(buf, in + j);
	return buf;
}

894
/*
895
 * It is okay if dst == src, but they should not overlap otherwise.
896
 *
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 * Performs the following normalizations on src, storing the result in dst:
 * - Ensures that components are separated by '/' (Windows only)
 * - Squashes sequences of '/'.
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 * - Removes "." components.
 * - Removes ".." components, and the components the precede them.
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 * Returns failure (non-zero) if a ".." component appears as first path
 * component anytime during the normalization. Otherwise, returns success (0).
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 *
 * 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.
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 *
 * 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.
 *
918
 */
919
int normalize_path_copy_len(char *dst, const char *src, int *prefix_len)
920
{
921
	char *dst0;
922

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	if (has_dos_drive_prefix(src)) {
		*dst++ = *src++;
		*dst++ = *src++;
926
	}
927
	dst0 = dst;
928

929
	if (is_dir_sep(*src)) {
930
		*dst++ = '/';
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		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;
				}
			}
		}
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		/* 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.
		 */
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		dst--;	/* go to trailing '/' */
		if (dst <= dst0)
990
			return -1;
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		/* Windows: dst[-1] cannot be backslash anymore */
		while (dst0 < dst && dst[-1] != '/')
			dst--;
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		if (prefix_len && *prefix_len > dst - dst0)
			*prefix_len = dst - dst0;
996
	}
997
	*dst = '\0';
998
	return 0;
999
}
1000

1001 1002 1003 1004 1005
int normalize_path_copy(char *dst, const char *src)
{
	return normalize_path_copy_len(dst, src, NULL);
}

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/*
 * path = Canonical absolute path
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 * prefixes = string_list containing normalized, absolute paths without
 * trailing slashes (except for the root directory, which is denoted by "/").
1010
 *
1011
 * Determines, for each path in prefixes, whether the "prefix"
1012 1013
 * is an ancestor directory of path.  Returns the length of the longest
 * ancestor directory, excluding any trailing slashes, or -1 if no prefix
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 * is an ancestor.  (Note that this means 0 is returned if prefixes is
 * ["/"].) "/foo" is not considered an ancestor of "/foobar".  Directories
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 * are not considered to be their own ancestors.  path must be in a
 * canonical form: empty components, or "." or ".." components are not
1018
 * allowed.
1019
 */
1020
int longest_ancestor_length(const char *path, struct string_list *prefixes)
1021
{
1022
	int i, max_len = -1;
1023

1024
	if (!strcmp(path, "/"))
1025 1026
		return -1;

1027 1028
	for (i = 0; i < prefixes->nr; i++) {
		const char *ceil = prefixes->items[i].string;
1029 1030
		int len = strlen(ceil);

1031 1032 1033 1034 1035 1036
		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 */
1037

1038
		if (len > max_len)
1039 1040 1041 1042 1043
			max_len = len;
	}

	return max_len;
}
1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079

/* 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));
}
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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()
1088
	 * does not do getcwd() based path canonicalization.
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126
	 *
	 * 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;
		}
	}
}
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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;
		}
}
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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;
}
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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")