X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=path.c;h=194e0b553f7a5c4fd99b348228112b308c5419b6;hb=e968751573a4ded76201a0e4414ec36649a92dda;hp=5b617092ad564739829d638938f36177611acf58;hpb=54f4b87454824fedc629219620ce9b7cdcab3d27;p=git.git

diff --git a/path.c b/path.c
index 5b617092..194e0b55 100644
--- a/path.c
+++ b/path.c
@@ -83,81 +83,198 @@ int git_mkstemp(char *path, size_t len, const char *template)
 }
 
 
-char *safe_strncpy(char *dest, const char *src, size_t n)
+size_t safe_strncpy(char *dest, const char *src, size_t size)
 {
-	strncpy(dest, src, n);
-	dest[n - 1] = '\0';
+	size_t ret = strlen(src);
 
-	return dest;
+	if (size) {
+		size_t len = (ret >= size) ? size - 1 : ret;
+		memcpy(dest, src, len);
+		dest[len] = '\0';
+	}
+	return ret;
 }
 
-static char *current_dir()
-{
-	return getcwd(pathname, sizeof(pathname));
-}
 
-/* Take a raw path from is_git_repo() and canonicalize it using Linus'
- * idea of a blind chdir() and getcwd(). */
-static const char *canonical_path(char *path, int strict)
+int validate_symref(const char *path)
 {
-	char *dir = path;
+	struct stat st;
+	char *buf, buffer[256];
+	int len, fd;
 
-	if(strict && *dir != '/')
-		return NULL;
+	if (lstat(path, &st) < 0)
+		return -1;
 
-	if(*dir == '~') {		/* user-relative path */
-		struct passwd *pw;
-		char *slash = strchr(dir, '/');
+	/* 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;
+	}
 
-		dir++;
-		/* '~/' and '~' (no slash) means users own home-dir */
-		if(!*dir || *dir == '/')
-			pw = getpwuid(getuid());
-		else {
-			if (slash) {
-				*slash = '\0';
-				pw = getpwnam(dir);
-				*slash = '/';
-			}
-			else
-				pw = getpwnam(dir);
-		}
+	/*
+	 * 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);
 
-		/* make sure we got something back that we can chdir() to */
-		if(!pw || chdir(pw->pw_dir) < 0)
-			return NULL;
+	/*
+	 * 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;
+}
 
-		if(!slash || !slash[1]) /* no path following username */
-			return current_dir();
+static char *user_path(char *buf, char *path, int sz)
+{
+	struct passwd *pw;
+	char *slash;
+	int len, baselen;
 
-		dir = slash + 1;
+	if (!path || path[0] != '~')
+		return NULL;
+	path++;
+	slash = strchr(path, '/');
+	if (path[0] == '/' || !path[0]) {
+		pw = getpwuid(getuid());
 	}
-
-	/* ~foo/path/to/repo is now path/to/repo and we're in foo's homedir */
-	if(chdir(dir) < 0)
+	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;
-
-	return current_dir();
+	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)
 {
-	if(!path)
+	static char used_path[PATH_MAX];
+	static char validated_path[PATH_MAX];
+
+	if (!path)
 		return NULL;
 
-	if(!canonical_path(path, strict)) {
-		if(strict || !canonical_path(mkpath("%s.git", path), strict))
+	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;
 
-	/* This is perfectly safe, and people tend to think of the directory
-	 * where they ran git-init-db as their repository, so humour them. */
-	(void)chdir(".git");
-
-	if(access("objects", X_OK) == 0 && access("refs", X_OK) == 0) {
+	if (access("objects", X_OK) == 0 && access("refs", X_OK) == 0 &&
+	    validate_symref("HEAD") == 0) {
 		putenv("GIT_DIR=.");
-		return current_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 |= S_IRGRP;
+	if (mode & S_IWUSR)
+		mode |= S_IWGRP;
+	if (mode & S_IXUSR)
+		mode |= S_IXGRP;
+	if (S_ISDIR(mode))
+		mode |= S_ISGID;
+	if (chmod(path, mode) < 0)
+		return -2;
+	return 0;
+}