[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)
{
	char *env, *pch = path;

	if ((env = getenv("TMPDIR")) == NULL) {
		strcpy(pch, "/tmp/");
		len -= 5;
		pch += 5;
	} else {
		size_t n = snprintf(pch, len, "%s/", env);

		len -= n;
		pch += n;
	}

	strlcpy(pch, template, len);

	return mkstemp(path);
}


int validate_symref(const char *path)
{
	struct stat st;
	char *buf, buffer[256];
	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(fd, buffer, sizeof(buffer)-1);
	close(fd);

	/*
	 * Is it a symbolic ref?
	 */
	if (len < 4 || memcmp("ref:", buffer, 4))
		return -1;
	buf = buffer + 4;
	len -= 4;
	while (len && isspace(*buf))
		buf++, len--;
	if (len >= 5 && !memcmp("refs/", buf, 5))
		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_symref("HEAD") == 0) {
		putenv("GIT_DIR=.");
		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	{
	74	char env, pch = path;
	75
	76	if ((env = getenv("TMPDIR")) == NULL) {
	77	strcpy(pch, "/tmp/");
	78	len -= 5;
35c3c629 HE	79	pch += 5;
	80	} else {
	81	size_t n = snprintf(pch, len, "%s/", env);
	82
	83	len -= n;
	84	pch += n;
	85	}
f2db68ed	86
817151e6	87	strlcpy(pch, template, len);
f2db68ed HE	88
	89	return mkstemp(path);
	90	}
	91
	92
0870ca7f JH	93	int validate_symref(const char *path)
	94	{
	95	struct stat st;
	96	char *buf, buffer[256];
	97	int len, fd;
	98
	99	if (lstat(path, &st) < 0)
	100	return -1;
	101
	102	/* Make sure it is a "refs/.." symlink */
	103	if (S_ISLNK(st.st_mode)) {
	104	len = readlink(path, buffer, sizeof(buffer)-1);
	105	if (len >= 5 && !memcmp("refs/", buffer, 5))
	106	return 0;
	107	return -1;
	108	}
	109
	110	/*
	111	* Anything else, just open it and try to see if it is a symbolic ref.
	112	*/
	113	fd = open(path, O_RDONLY);
	114	if (fd < 0)
	115	return -1;
	116	len = read(fd, buffer, sizeof(buffer)-1);
	117	close(fd);
	118
	119	/*
	120	* Is it a symbolic ref?
	121	*/
	122	if (len < 4 \|\| memcmp("ref:", buffer, 4))
	123	return -1;
	124	buf = buffer + 4;
	125	len -= 4;
	126	while (len && isspace(*buf))
	127	buf++, len--;
	128	if (len >= 5 && !memcmp("refs/", buf, 5))
	129	return 0;
	130	return -1;
	131	}
	132
d79374c7	133	static char user_path(char buf, char *path, int sz)
54f4b874	134	{
d79374c7 JH	135	struct passwd *pw;
	136	char *slash;
	137	int len, baselen;
54f4b874	138
d79374c7 JH	139	if (!path \|\| path[0] != '~')
	140	return NULL;
	141	path++;
	142	slash = strchr(path, '/');
	143	if (path[0] == '/' \|\| !path[0]) {
	144	pw = getpwuid(getuid());
	145	}
	146	else {
	147	if (slash) {
	148	*slash = 0;
	149	pw = getpwnam(path);
	150	*slash = '/';
54f4b874	151	}
d79374c7 JH	152	else
d79374c7 JH	153	pw = getpwnam(path);
54f4b874	154	}
d79374c7 JH	155	if (!pw \|\| !pw->pw_dir \|\| sz <= strlen(pw->pw_dir))
	156	return NULL;
	157	baselen = strlen(pw->pw_dir);
	158	memcpy(buf, pw->pw_dir, baselen);
	159	while ((1 < baselen) && (buf[baselen-1] == '/')) {
	160	buf[baselen-1] = 0;
	161	baselen--;
	162	}
	163	if (slash && slash[1]) {
	164	len = strlen(slash);
	165	if (sz <= baselen + len)
	166	return NULL;
	167	memcpy(buf + baselen, slash, len + 1);
	168	}
	169	return buf;
54f4b874 AE	170	}
54f4b874 AE	171
d79374c7 JH	172	/*
	173	* First, one directory to try is determined by the following algorithm.
	174	*
	175	* (0) If "strict" is given, the path is used as given and no DWIM is
	176	* done. Otherwise:
	177	* (1) "~/path" to mean path under the running user's home directory;
	178	* (2) "~user/path" to mean path under named user's home directory;
	179	* (3) "relative/path" to mean cwd relative directory; or
	180	* (4) "/absolute/path" to mean absolute directory.
	181	*
	182	* Unless "strict" is given, we try access() for existence of "%s.git/.git",
	183	* "%s/.git", "%s.git", "%s" in this order. The first one that exists is
	184	* what we try.
	185	*
	186	* Second, we try chdir() to that. Upon failure, we return NULL.
	187	*
	188	* Then, we try if the current directory is a valid git repository.
	189	* Upon failure, we return NULL.
	190	*
	191	* If all goes well, we return the directory we used to chdir() (but
	192	* before ~user is expanded), avoiding getcwd() resolving symbolic
	193	* links. User relative paths are also returned as they are given,
	194	* except DWIM suffixing.
	195	*/
54f4b874 AE	196	char enter_repo(char path, int strict)
54f4b874 AE	197	{
d79374c7 JH	198	static char used_path[PATH_MAX];
	199	static char validated_path[PATH_MAX];
	200
	201	if (!path)
54f4b874 AE	202	return NULL;
54f4b874 AE	203
d79374c7 JH	204	if (!strict) {
	205	static const char *suffix[] = {
	206	".git/.git", "/.git", ".git", "", NULL,
	207	};
	208	int len = strlen(path);
	209	int i;
	210	while ((1 < len) && (path[len-1] == '/')) {
	211	path[len-1] = 0;
	212	len--;
	213	}
	214	if (PATH_MAX <= len)
54f4b874	215	return NULL;
d79374c7 JH	216	if (path[0] == '~') {
	217	if (!user_path(used_path, path, PATH_MAX))
	218	return NULL;
	219	strcpy(validated_path, path);
	220	path = used_path;
	221	}
	222	else if (PATH_MAX - 10 < len)
	223	return NULL;
	224	else {
	225	path = strcpy(used_path, path);
	226	strcpy(validated_path, path);
	227	}
	228	len = strlen(path);
	229	for (i = 0; suffix[i]; i++) {
	230	strcpy(path + len, suffix[i]);
	231	if (!access(path, F_OK)) {
	232	strcat(validated_path, suffix[i]);
	233	break;
	234	}
	235	}
	236	if (!suffix[i] \|\| chdir(path))
0870ca7f	237	return NULL;
d79374c7	238	path = validated_path;
0870ca7f	239	}
d79374c7 JH	240	else if (chdir(path))
d79374c7 JH	241	return NULL;
54f4b874	242
d79374c7 JH	243	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
d79374c7 JH	244	validate_symref("HEAD") == 0) {
54f4b874	245	putenv("GIT_DIR=.");
1644162a	246	check_repository_format();
d79374c7	247	return path;
54f4b874 AE	248	}
	249
	250	return NULL;
	251	}
138086a7 JH	252
	253	int adjust_shared_perm(const char *path)
	254	{
	255	struct stat st;
	256	int mode;
	257
	258	if (!shared_repository)
	259	return 0;
	260	if (lstat(path, &st) < 0)
	261	return -1;
	262	mode = st.st_mode;
	263	if (mode & S_IRUSR)
94df2506 JH	264	mode \|= (shared_repository == PERM_GROUP
	265	? S_IRGRP
	266	: (shared_repository == PERM_EVERYBODY
	267	? (S_IRGRP\|S_IROTH)
	268	: 0));
	269
138086a7 JH	270	if (mode & S_IWUSR)
138086a7 JH	271	mode \|= S_IWGRP;
94df2506	272
138086a7	273	if (mode & S_IXUSR)
94df2506 JH	274	mode \|= (shared_repository == PERM_GROUP
	275	? S_IXGRP
	276	: (shared_repository == PERM_EVERYBODY
	277	? (S_IXGRP\|S_IXOTH)
	278	: 0));
138086a7 JH	279	if (S_ISDIR(mode))
138086a7 JH	280	mode \|= S_ISGID;
fe732ede	281	if ((mode & st.st_mode) != mode && chmod(path, mode) < 0)
138086a7 JH	282	return -2;
	283	return 0;
	284	}