[thirdparty/git.git] / path.c

/*
 * I'm tired of doing "vsnprintf()" etc just to open a
 * file, so here's a "return static buffer with printf"
 * interface for paths.
 *
 * It's obviously not thread-safe. Sue me. But it's quite
 * useful for doing things like
 *
 *   f = open(mkpath("%s/%s.git", base, name), O_RDONLY);
 *
 * which is what it's designed for.
 */
#include "cache.h"

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

static char *get_pathname(void)
{
	static char pathname_array[4][PATH_MAX];
	static int index;
	return pathname_array[3 & ++index];
}

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

char *mkpath(const char *fmt, ...)
{
	va_list args;
	unsigned len;
	char *pathname = get_pathname();

	va_start(args, fmt);
	len = vsnprintf(pathname, PATH_MAX, fmt, args);
	va_end(args);
	if (len >= PATH_MAX)
		return bad_path;
	return cleanup_path(pathname);
}

char *git_path(const char *fmt, ...)
{
	const char *git_dir = get_git_dir();
	char *pathname = get_pathname();
	va_list args;
	unsigned len;

	len = strlen(git_dir);
	if (len > PATH_MAX-100)
		return bad_path;
	memcpy(pathname, git_dir, len);
	if (len && git_dir[len-1] != '/')
		pathname[len++] = '/';
	va_start(args, fmt);
	len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
	va_end(args);
	if (len >= PATH_MAX)
		return bad_path;
	return cleanup_path(pathname);
}


/* git_mkstemp() - create tmp file honoring TMPDIR variable */
int git_mkstemp(char *path, size_t len, const char *template)
{
	const char *tmp;
	size_t n;

	tmp = getenv("TMPDIR");
	if (!tmp)
		tmp = "/tmp";
	n = snprintf(path, len, "%s/%s", tmp, template);
	if (len <= n) {
		errno = ENAMETOOLONG;
		return -1;
	}
	return mkstemp(path);
}


int validate_headref(const char *path)
{
	struct stat st;
	char *buf, buffer[256];
	unsigned char sha1[20];
	int fd;
	ssize_t len;

	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);
		if (len >= 5 && !memcmp("refs/", buffer, 5))
			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;
	len = read_in_full(fd, buffer, sizeof(buffer)-1);
	close(fd);

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

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

	return -1;
}

static char *user_path(char *buf, char *path, int sz)
{
	struct passwd *pw;
	char *slash;
	int len, baselen;

	if (!path || path[0] != '~')
		return NULL;
	path++;
	slash = strchr(path, '/');
	if (path[0] == '/' || !path[0]) {
		pw = getpwuid(getuid());
	}
	else {
		if (slash) {
			*slash = 0;
			pw = getpwnam(path);
			*slash = '/';
		}
		else
			pw = getpwnam(path);
	}
	if (!pw || !pw->pw_dir || sz <= strlen(pw->pw_dir))
		return NULL;
	baselen = strlen(pw->pw_dir);
	memcpy(buf, pw->pw_dir, baselen);
	while ((1 < baselen) && (buf[baselen-1] == '/')) {
		buf[baselen-1] = 0;
		baselen--;
	}
	if (slash && slash[1]) {
		len = strlen(slash);
		if (sz <= baselen + len)
			return NULL;
		memcpy(buf + baselen, slash, len + 1);
	}
	return buf;
}

/*
 * 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.
 *
 * Unless "strict" is given, we try access() for existence of "%s.git/.git",
 * "%s/.git", "%s.git", "%s" in this order.  The first one that exists is
 * what we try.
 *
 * Second, we try chdir() to that.  Upon failure, we return NULL.
 *
 * Then, we try if the current directory is a valid git repository.
 * Upon failure, we return NULL.
 *
 * 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.
 */
char *enter_repo(char *path, int strict)
{
	static char used_path[PATH_MAX];
	static char validated_path[PATH_MAX];

	if (!path)
		return NULL;

	if (!strict) {
		static const char *suffix[] = {
			".git/.git", "/.git", ".git", "", NULL,
		};
		int len = strlen(path);
		int i;
		while ((1 < len) && (path[len-1] == '/')) {
			path[len-1] = 0;
			len--;
		}
		if (PATH_MAX <= len)
			return NULL;
		if (path[0] == '~') {
			if (!user_path(used_path, path, PATH_MAX))
				return NULL;
			strcpy(validated_path, path);
			path = used_path;
		}
		else if (PATH_MAX - 10 < len)
			return NULL;
		else {
			path = strcpy(used_path, path);
			strcpy(validated_path, path);
		}
		len = strlen(path);
		for (i = 0; suffix[i]; i++) {
			strcpy(path + len, suffix[i]);
			if (!access(path, F_OK)) {
				strcat(validated_path, suffix[i]);
				break;
			}
		}
		if (!suffix[i] || chdir(path))
			return NULL;
		path = validated_path;
	}
	else if (chdir(path))
		return NULL;

	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
	    validate_headref("HEAD") == 0) {
		setenv(GIT_DIR_ENVIRONMENT, ".", 1);
		check_repository_format();
		return path;
	}

	return NULL;
}

int adjust_shared_perm(const char *path)
{
	struct stat st;
	int mode;

	if (!shared_repository)
		return 0;
	if (lstat(path, &st) < 0)
		return -1;
	mode = st.st_mode;

	if (shared_repository) {
		int tweak = shared_repository;
		if (!(mode & S_IWUSR))
			tweak &= ~0222;
		mode = (mode & ~0777) | tweak;
	} else {
		/* Preserve old PERM_UMASK behaviour */
		if (mode & S_IWUSR)
			mode |= S_IWGRP;
	}

	if (S_ISDIR(mode)) {
		mode |= FORCE_DIR_SET_GID;

		/* Copy read bits to execute bits */
		mode |= (shared_repository & 0444) >> 2;
	}

	if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
		return -2;
	return 0;
}

/* We allow "recursive" symbolic links. Only within reason, though. */
#define MAXDEPTH 5

const char *make_absolute_path(const char *path)
{
	static char bufs[2][PATH_MAX + 1], *buf = bufs[0], *next_buf = bufs[1];
	char cwd[1024] = "";
	int buf_index = 1, len;

	int depth = MAXDEPTH;
	char *last_elem = NULL;
	struct stat st;

	if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
		die ("Too long path: %.*s", 60, path);

	while (depth--) {
		if (stat(buf, &st) || !S_ISDIR(st.st_mode)) {
			char *last_slash = strrchr(buf, '/');
			if (last_slash) {
				*last_slash = '\0';
				last_elem = xstrdup(last_slash + 1);
			} else {
				last_elem = xstrdup(buf);
				*buf = '\0';
			}
		}

		if (*buf) {
			if (!*cwd && !getcwd(cwd, sizeof(cwd)))
				die ("Could not get current working directory");

			if (chdir(buf))
				die ("Could not switch to '%s'", buf);
		}
		if (!getcwd(buf, PATH_MAX))
			die ("Could not get current working directory");

		if (last_elem) {
			int len = strlen(buf);
			if (len + strlen(last_elem) + 2 > PATH_MAX)
				die ("Too long path name: '%s/%s'",
						buf, last_elem);
			buf[len] = '/';
			strcpy(buf + len + 1, last_elem);
			free(last_elem);
			last_elem = NULL;
		}

		if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
			len = readlink(buf, next_buf, PATH_MAX);
			if (len < 0)
				die ("Invalid symlink: %s", buf);
			next_buf[len] = '\0';
			buf = next_buf;
			buf_index = 1 - buf_index;
			next_buf = bufs[buf_index];
		} else
			break;
	}

	if (*cwd && chdir(cwd))
		die ("Could not change back to '%s'", cwd);

	return buf;
}
Commit	Line	Data
26c8a533 LT	1	/*
	2	* I'm tired of doing "vsnprintf()" etc just to open a
	3	* file, so here's a "return static buffer with printf"
	4	* interface for paths.
	5	*
	6	* It's obviously not thread-safe. Sue me. But it's quite
	7	* useful for doing things like
	8	*
	9	* f = open(mkpath("%s/%s.git", base, name), O_RDONLY);
	10	*
	11	* which is what it's designed for.
	12	*/
	13	#include "cache.h"
	14
26c8a533 LT	15	static char bad_path[] = "/bad-path/";
26c8a533 LT	16
e7676d2f LT	17	static char *get_pathname(void)
	18	{
	19	static char pathname_array[4][PATH_MAX];
	20	static int index;
	21	return pathname_array[3 & ++index];
	22	}
	23
26c8a533 LT	24	static char cleanup_path(char path)
	25	{
	26	/* Clean it up */
	27	if (!memcmp(path, "./", 2)) {
	28	path += 2;
	29	while (*path == '/')
	30	path++;
	31	}
	32	return path;
	33	}
	34
	35	char mkpath(const char fmt, ...)
	36	{
	37	va_list args;
	38	unsigned len;
e7676d2f	39	char *pathname = get_pathname();
26c8a533 LT	40
	41	va_start(args, fmt);
	42	len = vsnprintf(pathname, PATH_MAX, fmt, args);
	43	va_end(args);
	44	if (len >= PATH_MAX)
	45	return bad_path;
	46	return cleanup_path(pathname);
	47	}
	48
	49	char git_path(const char fmt, ...)
	50	{
5da1606d	51	const char *git_dir = get_git_dir();
e7676d2f	52	char *pathname = get_pathname();
26c8a533 LT	53	va_list args;
	54	unsigned len;
	55
	56	len = strlen(git_dir);
	57	if (len > PATH_MAX-100)
	58	return bad_path;
	59	memcpy(pathname, git_dir, len);
	60	if (len && git_dir[len-1] != '/')
	61	pathname[len++] = '/';
	62	va_start(args, fmt);
	63	len += vsnprintf(pathname + len, PATH_MAX - len, fmt, args);
	64	va_end(args);
	65	if (len >= PATH_MAX)
	66	return bad_path;
	67	return cleanup_path(pathname);
	68	}
f2db68ed HE	69
	70
	71	/* git_mkstemp() - create tmp file honoring TMPDIR variable */
	72	int git_mkstemp(char path, size_t len, const char template)
	73	{
e7a7be88 JH	74	const char *tmp;
	75	size_t n;
	76
	77	tmp = getenv("TMPDIR");
	78	if (!tmp)
	79	tmp = "/tmp";
	80	n = snprintf(path, len, "%s/%s", tmp, template);
	81	if (len <= n) {
	82	errno = ENAMETOOLONG;
	83	return -1;
35c3c629	84	}
f2db68ed HE	85	return mkstemp(path);
	86	}
	87
	88
c847f537	89	int validate_headref(const char *path)
0870ca7f JH	90	{
	91	struct stat st;
	92	char *buf, buffer[256];
c847f537	93	unsigned char sha1[20];
0104ca09 HO	94	int fd;
0104ca09 HO	95	ssize_t len;
0870ca7f JH	96
	97	if (lstat(path, &st) < 0)
	98	return -1;
	99
	100	/* Make sure it is a "refs/.." symlink */
	101	if (S_ISLNK(st.st_mode)) {
	102	len = readlink(path, buffer, sizeof(buffer)-1);
	103	if (len >= 5 && !memcmp("refs/", buffer, 5))
	104	return 0;
	105	return -1;
	106	}
	107
	108	/*
	109	* Anything else, just open it and try to see if it is a symbolic ref.
	110	*/
	111	fd = open(path, O_RDONLY);
	112	if (fd < 0)
	113	return -1;
93d26e4c	114	len = read_in_full(fd, buffer, sizeof(buffer)-1);
0870ca7f JH	115	close(fd);
	116
	117	/*
	118	* Is it a symbolic ref?
	119	*/
c847f537	120	if (len < 4)
0870ca7f	121	return -1;
c847f537 JH	122	if (!memcmp("ref:", buffer, 4)) {
	123	buf = buffer + 4;
	124	len -= 4;
	125	while (len && isspace(*buf))
	126	buf++, len--;
	127	if (len >= 5 && !memcmp("refs/", buf, 5))
	128	return 0;
	129	}
	130
	131	/*
	132	* Is this a detached HEAD?
	133	*/
	134	if (!get_sha1_hex(buffer, sha1))
0870ca7f	135	return 0;
c847f537	136
0870ca7f JH	137	return -1;
	138	}
	139
d79374c7	140	static char user_path(char buf, char *path, int sz)
54f4b874	141	{
d79374c7 JH	142	struct passwd *pw;
	143	char *slash;
	144	int len, baselen;
54f4b874	145
d79374c7 JH	146	if (!path \|\| path[0] != '~')
	147	return NULL;
	148	path++;
	149	slash = strchr(path, '/');
	150	if (path[0] == '/' \|\| !path[0]) {
	151	pw = getpwuid(getuid());
	152	}
	153	else {
	154	if (slash) {
	155	*slash = 0;
	156	pw = getpwnam(path);
	157	*slash = '/';
54f4b874	158	}
d79374c7 JH	159	else
d79374c7 JH	160	pw = getpwnam(path);
54f4b874	161	}
d79374c7 JH	162	if (!pw \|\| !pw->pw_dir \|\| sz <= strlen(pw->pw_dir))
	163	return NULL;
	164	baselen = strlen(pw->pw_dir);
	165	memcpy(buf, pw->pw_dir, baselen);
	166	while ((1 < baselen) && (buf[baselen-1] == '/')) {
	167	buf[baselen-1] = 0;
	168	baselen--;
	169	}
	170	if (slash && slash[1]) {
	171	len = strlen(slash);
	172	if (sz <= baselen + len)
	173	return NULL;
	174	memcpy(buf + baselen, slash, len + 1);
	175	}
	176	return buf;
54f4b874 AE	177	}
54f4b874 AE	178
d79374c7 JH	179	/*
	180	* First, one directory to try is determined by the following algorithm.
	181	*
	182	* (0) If "strict" is given, the path is used as given and no DWIM is
	183	* done. Otherwise:
	184	* (1) "~/path" to mean path under the running user's home directory;
	185	* (2) "~user/path" to mean path under named user's home directory;
	186	* (3) "relative/path" to mean cwd relative directory; or
	187	* (4) "/absolute/path" to mean absolute directory.
	188	*
	189	* Unless "strict" is given, we try access() for existence of "%s.git/.git",
	190	* "%s/.git", "%s.git", "%s" in this order. The first one that exists is
	191	* what we try.
	192	*
	193	* Second, we try chdir() to that. Upon failure, we return NULL.
	194	*
	195	* Then, we try if the current directory is a valid git repository.
	196	* Upon failure, we return NULL.
	197	*
	198	* If all goes well, we return the directory we used to chdir() (but
	199	* before ~user is expanded), avoiding getcwd() resolving symbolic
	200	* links. User relative paths are also returned as they are given,
	201	* except DWIM suffixing.
	202	*/
54f4b874 AE	203	char enter_repo(char path, int strict)
54f4b874 AE	204	{
d79374c7 JH	205	static char used_path[PATH_MAX];
	206	static char validated_path[PATH_MAX];
	207
	208	if (!path)
54f4b874 AE	209	return NULL;
54f4b874 AE	210
d79374c7 JH	211	if (!strict) {
	212	static const char *suffix[] = {
	213	".git/.git", "/.git", ".git", "", NULL,
	214	};
	215	int len = strlen(path);
	216	int i;
	217	while ((1 < len) && (path[len-1] == '/')) {
	218	path[len-1] = 0;
	219	len--;
	220	}
	221	if (PATH_MAX <= len)
54f4b874	222	return NULL;
d79374c7 JH	223	if (path[0] == '~') {
	224	if (!user_path(used_path, path, PATH_MAX))
	225	return NULL;
	226	strcpy(validated_path, path);
	227	path = used_path;
	228	}
	229	else if (PATH_MAX - 10 < len)
	230	return NULL;
	231	else {
	232	path = strcpy(used_path, path);
	233	strcpy(validated_path, path);
	234	}
	235	len = strlen(path);
	236	for (i = 0; suffix[i]; i++) {
	237	strcpy(path + len, suffix[i]);
	238	if (!access(path, F_OK)) {
	239	strcat(validated_path, suffix[i]);
	240	break;
	241	}
	242	}
	243	if (!suffix[i] \|\| chdir(path))
0870ca7f	244	return NULL;
d79374c7	245	path = validated_path;
0870ca7f	246	}
d79374c7 JH	247	else if (chdir(path))
d79374c7 JH	248	return NULL;
54f4b874	249
d79374c7	250	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
c847f537	251	validate_headref("HEAD") == 0) {
7627943a	252	setenv(GIT_DIR_ENVIRONMENT, ".", 1);
1644162a	253	check_repository_format();
d79374c7	254	return path;
54f4b874 AE	255	}
	256
	257	return NULL;
	258	}
138086a7 JH	259
	260	int adjust_shared_perm(const char *path)
	261	{
	262	struct stat st;
	263	int mode;
	264
	265	if (!shared_repository)
	266	return 0;
	267	if (lstat(path, &st) < 0)
	268	return -1;
	269	mode = st.st_mode;
06cbe855 HO	270
	271	if (shared_repository) {
	272	int tweak = shared_repository;
	273	if (!(mode & S_IWUSR))
	274	tweak &= ~0222;
	275	mode = (mode & ~0777) \| tweak;
	276	} else {
	277	/* Preserve old PERM_UMASK behaviour */
	278	if (mode & S_IWUSR)
	279	mode \|= S_IWGRP;
	280	}
	281
	282	if (S_ISDIR(mode)) {
81a24b52	283	mode \|= FORCE_DIR_SET_GID;
06cbe855 HO	284
	285	/* Copy read bits to execute bits */
	286	mode \|= (shared_repository & 0444) >> 2;
	287	}
	288
fe732ede	289	if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
138086a7 JH	290	return -2;
	291	return 0;
	292	}
e5392c51 JS	293
	294	/* We allow "recursive" symbolic links. Only within reason, though. */
	295	#define MAXDEPTH 5
	296
	297	const char make_absolute_path(const char path)
	298	{
	299	static char bufs[2][PATH_MAX + 1], buf = bufs[0], next_buf = bufs[1];
	300	char cwd[1024] = "";
	301	int buf_index = 1, len;
	302
	303	int depth = MAXDEPTH;
	304	char *last_elem = NULL;
	305	struct stat st;
	306
	307	if (strlcpy(buf, path, PATH_MAX) >= PATH_MAX)
	308	die ("Too long path: %.*s", 60, path);
	309
	310	while (depth--) {
	311	if (stat(buf, &st) \|\| !S_ISDIR(st.st_mode)) {
	312	char *last_slash = strrchr(buf, '/');
	313	if (last_slash) {
	314	*last_slash = '\0';
	315	last_elem = xstrdup(last_slash + 1);
e371a4c6	316	} else {
e5392c51	317	last_elem = xstrdup(buf);
e371a4c6 JS	318	*buf = '\0';
e371a4c6 JS	319	}
e5392c51 JS	320	}
	321
	322	if (*buf) {
	323	if (!*cwd && !getcwd(cwd, sizeof(cwd)))
	324	die ("Could not get current working directory");
	325
	326	if (chdir(buf))
	327	die ("Could not switch to '%s'", buf);
	328	}
	329	if (!getcwd(buf, PATH_MAX))
	330	die ("Could not get current working directory");
	331
	332	if (last_elem) {
	333	int len = strlen(buf);
	334	if (len + strlen(last_elem) + 2 > PATH_MAX)
	335	die ("Too long path name: '%s/%s'",
	336	buf, last_elem);
	337	buf[len] = '/';
	338	strcpy(buf + len + 1, last_elem);
	339	free(last_elem);
	340	last_elem = NULL;
	341	}
	342
	343	if (!lstat(buf, &st) && S_ISLNK(st.st_mode)) {
	344	len = readlink(buf, next_buf, PATH_MAX);
	345	if (len < 0)
	346	die ("Invalid symlink: %s", buf);
	347	next_buf[len] = '\0';
	348	buf = next_buf;
	349	buf_index = 1 - buf_index;
	350	next_buf = bufs[buf_index];
	351	} else
	352	break;
	353	}
	354
	355	if (*cwd && chdir(cwd))
	356	die ("Could not change back to '%s'", cwd);
	357
	358	return buf;
	359	}