[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 len, fd;

	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 (mode & S_IRUSR)
		mode |= (shared_repository == PERM_GROUP
			 ? S_IRGRP
			 : (shared_repository == PERM_EVERYBODY
			    ? (S_IRGRP|S_IROTH)
			    : 0));

	if (mode & S_IWUSR)
		mode |= S_IWGRP;

	if (mode & S_IXUSR)
		mode |= (shared_repository == PERM_GROUP
			 ? S_IXGRP
			 : (shared_repository == PERM_EVERYBODY
			    ? (S_IXGRP|S_IXOTH)
			    : 0));
	if (S_ISDIR(mode))
		mode |= S_ISGID;
	if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
		return -2;
	return 0;
}
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];
0870ca7f JH	94	int len, fd;
	95
	96	if (lstat(path, &st) < 0)
	97	return -1;
	98
	99	/* Make sure it is a "refs/.." symlink */
	100	if (S_ISLNK(st.st_mode)) {
	101	len = readlink(path, buffer, sizeof(buffer)-1);
	102	if (len >= 5 && !memcmp("refs/", buffer, 5))
	103	return 0;
	104	return -1;
	105	}
	106
	107	/*
	108	* Anything else, just open it and try to see if it is a symbolic ref.
	109	*/
	110	fd = open(path, O_RDONLY);
	111	if (fd < 0)
	112	return -1;
93d26e4c	113	len = read_in_full(fd, buffer, sizeof(buffer)-1);
0870ca7f JH	114	close(fd);
	115
	116	/*
	117	* Is it a symbolic ref?
	118	*/
c847f537	119	if (len < 4)
0870ca7f	120	return -1;
c847f537 JH	121	if (!memcmp("ref:", buffer, 4)) {
	122	buf = buffer + 4;
	123	len -= 4;
	124	while (len && isspace(*buf))
	125	buf++, len--;
	126	if (len >= 5 && !memcmp("refs/", buf, 5))
	127	return 0;
	128	}
	129
	130	/*
	131	* Is this a detached HEAD?
	132	*/
	133	if (!get_sha1_hex(buffer, sha1))
0870ca7f	134	return 0;
c847f537	135
0870ca7f JH	136	return -1;
	137	}
	138
d79374c7	139	static char user_path(char buf, char *path, int sz)
54f4b874	140	{
d79374c7 JH	141	struct passwd *pw;
	142	char *slash;
	143	int len, baselen;
54f4b874	144
d79374c7 JH	145	if (!path \|\| path[0] != '~')
	146	return NULL;
	147	path++;
	148	slash = strchr(path, '/');
	149	if (path[0] == '/' \|\| !path[0]) {
	150	pw = getpwuid(getuid());
	151	}
	152	else {
	153	if (slash) {
	154	*slash = 0;
	155	pw = getpwnam(path);
	156	*slash = '/';
54f4b874	157	}
d79374c7 JH	158	else
d79374c7 JH	159	pw = getpwnam(path);
54f4b874	160	}
d79374c7 JH	161	if (!pw \|\| !pw->pw_dir \|\| sz <= strlen(pw->pw_dir))
	162	return NULL;
	163	baselen = strlen(pw->pw_dir);
	164	memcpy(buf, pw->pw_dir, baselen);
	165	while ((1 < baselen) && (buf[baselen-1] == '/')) {
	166	buf[baselen-1] = 0;
	167	baselen--;
	168	}
	169	if (slash && slash[1]) {
	170	len = strlen(slash);
	171	if (sz <= baselen + len)
	172	return NULL;
	173	memcpy(buf + baselen, slash, len + 1);
	174	}
	175	return buf;
54f4b874 AE	176	}
54f4b874 AE	177
d79374c7 JH	178	/*
	179	* First, one directory to try is determined by the following algorithm.
	180	*
	181	* (0) If "strict" is given, the path is used as given and no DWIM is
	182	* done. Otherwise:
	183	* (1) "~/path" to mean path under the running user's home directory;
	184	* (2) "~user/path" to mean path under named user's home directory;
	185	* (3) "relative/path" to mean cwd relative directory; or
	186	* (4) "/absolute/path" to mean absolute directory.
	187	*
	188	* Unless "strict" is given, we try access() for existence of "%s.git/.git",
	189	* "%s/.git", "%s.git", "%s" in this order. The first one that exists is
	190	* what we try.
	191	*
	192	* Second, we try chdir() to that. Upon failure, we return NULL.
	193	*
	194	* Then, we try if the current directory is a valid git repository.
	195	* Upon failure, we return NULL.
	196	*
	197	* If all goes well, we return the directory we used to chdir() (but
	198	* before ~user is expanded), avoiding getcwd() resolving symbolic
	199	* links. User relative paths are also returned as they are given,
	200	* except DWIM suffixing.
	201	*/
54f4b874 AE	202	char enter_repo(char path, int strict)
54f4b874 AE	203	{
d79374c7 JH	204	static char used_path[PATH_MAX];
	205	static char validated_path[PATH_MAX];
	206
	207	if (!path)
54f4b874 AE	208	return NULL;
54f4b874 AE	209
d79374c7 JH	210	if (!strict) {
	211	static const char *suffix[] = {
	212	".git/.git", "/.git", ".git", "", NULL,
	213	};
	214	int len = strlen(path);
	215	int i;
	216	while ((1 < len) && (path[len-1] == '/')) {
	217	path[len-1] = 0;
	218	len--;
	219	}
	220	if (PATH_MAX <= len)
54f4b874	221	return NULL;
d79374c7 JH	222	if (path[0] == '~') {
	223	if (!user_path(used_path, path, PATH_MAX))
	224	return NULL;
	225	strcpy(validated_path, path);
	226	path = used_path;
	227	}
	228	else if (PATH_MAX - 10 < len)
	229	return NULL;
	230	else {
	231	path = strcpy(used_path, path);
	232	strcpy(validated_path, path);
	233	}
	234	len = strlen(path);
	235	for (i = 0; suffix[i]; i++) {
	236	strcpy(path + len, suffix[i]);
	237	if (!access(path, F_OK)) {
	238	strcat(validated_path, suffix[i]);
	239	break;
	240	}
	241	}
	242	if (!suffix[i] \|\| chdir(path))
0870ca7f	243	return NULL;
d79374c7	244	path = validated_path;
0870ca7f	245	}
d79374c7 JH	246	else if (chdir(path))
d79374c7 JH	247	return NULL;
54f4b874	248
d79374c7	249	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
c847f537	250	validate_headref("HEAD") == 0) {
7627943a	251	setenv(GIT_DIR_ENVIRONMENT, ".", 1);
1644162a	252	check_repository_format();
d79374c7	253	return path;
54f4b874 AE	254	}
	255
	256	return NULL;
	257	}
138086a7 JH	258
	259	int adjust_shared_perm(const char *path)
	260	{
	261	struct stat st;
	262	int mode;
	263
	264	if (!shared_repository)
	265	return 0;
	266	if (lstat(path, &st) < 0)
	267	return -1;
	268	mode = st.st_mode;
	269	if (mode & S_IRUSR)
94df2506 JH	270	mode \|= (shared_repository == PERM_GROUP
	271	? S_IRGRP
	272	: (shared_repository == PERM_EVERYBODY
	273	? (S_IRGRP\|S_IROTH)
	274	: 0));
	275
138086a7 JH	276	if (mode & S_IWUSR)
138086a7 JH	277	mode \|= S_IWGRP;
94df2506	278
138086a7	279	if (mode & S_IXUSR)
94df2506 JH	280	mode \|= (shared_repository == PERM_GROUP
	281	? S_IXGRP
	282	: (shared_repository == PERM_EVERYBODY
	283	? (S_IXGRP\|S_IXOTH)
	284	: 0));
138086a7 JH	285	if (S_ISDIR(mode))
138086a7 JH	286	mode \|= S_ISGID;
fe732ede	287	if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
138086a7 JH	288	return -2;
	289	return 0;
	290	}