Prevent adding .git/.gitmodules only in the root of the repository.

This allows adding .git files and directories as long as they are
not in the root.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
 dir.c        |  3 ++-
 read-cache.c | 59 +++++++++++++++++++++++++++++++---------------------
 2 files changed, 37 insertions(+), 25 deletions(-)

diff --git a/dir.c b/dir.c
index fe64be30ed..a959885f50 100644
--- a/dir.c
+++ b/dir.c
@@ -2145,7 +2145,8 @@ static enum path_treatment treat_path(struct dir_struct *dir,
 	if (!cdir->d_name)
 		return treat_path_fast(dir, untracked, cdir, istate, path,
 				       baselen, pathspec);
-	if (is_dot_or_dotdot(cdir->d_name) || !fspathcmp(cdir->d_name, ".git"))
+	if (is_dot_or_dotdot(cdir->d_name) ||
+	    (path->len == 0 && !fspathcmp(cdir->d_name, ".git")))
 		return path_none;
 	strbuf_setlen(path, baselen);
 	strbuf_addstr(path, cdir->d_name);
diff --git a/read-cache.c b/read-cache.c
index 8ed1c29b54..7fb25c23d5 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -906,12 +906,7 @@ int ce_same_name(const struct cache_entry *a, const struct cache_entry *b)
 }
 
 /*
- * We fundamentally don't like some paths: we don't want
- * dot or dot-dot anywhere, and for obvious reasons don't
- * want to recurse into ".git" either.
- *
- * Also, we don't want double slashes or slashes at the
- * end that can make pathnames ambiguous.
+ * We don't want dot or dot-dot anywhere
  */
 static int verify_dotfile(const char *rest, unsigned mode)
 {
@@ -922,10 +917,24 @@ static int verify_dotfile(const char *rest, unsigned mode)
 	 */
 
 	/* "." is not allowed */
-	if (*rest == '\0' || is_dir_sep(*rest))
+	if (rest[0] == '\0' || is_dir_sep(rest[0]))
+		return 0;
+
+	/* ".." is not allowed */
+	if (rest[0] == '.' && (rest[1] == '\0' || is_dir_sep(rest[1])))
 		return 0;
 
-	switch (*rest) {
+	return 1;
+}
+
+static int verify_dotgit(const char *rest, unsigned mode)
+{
+	/*
+	 * The first character was '.', but that
+	 * has already been discarded, we now test
+	 * the rest.
+	 */
+
 	/*
 	 * ".git" followed by NUL or slash is bad. Note that we match
 	 * case-insensitively here, even if ignore_case is not set.
@@ -935,12 +944,11 @@ static int verify_dotfile(const char *rest, unsigned mode)
 	 * Once we've seen ".git", we can also find ".gitmodules", etc (also
 	 * case-insensitively).
 	 */
-	case 'g':
-	case 'G':
+	if (rest[0] == 'g' || rest[0] == 'G') {
 		if (rest[1] != 'i' && rest[1] != 'I')
-			break;
+			return 1;
 		if (rest[2] != 't' && rest[2] != 'T')
-			break;
+			return 1;
 		if (rest[3] == '\0' || is_dir_sep(rest[3]))
 			return 0;
 		if (S_ISLNK(mode)) {
@@ -949,17 +957,16 @@ static int verify_dotfile(const char *rest, unsigned mode)
 			    (*rest == '\0' || is_dir_sep(*rest)))
 				return 0;
 		}
-		break;
-	case '.':
-		if (rest[1] == '\0' || is_dir_sep(rest[1]))
-			return 0;
 	}
+
 	return 1;
 }
 
 int verify_path(const char *path, unsigned mode)
 {
+	const char *orig_path = path;
 	char c = 0;
+	#define is_root(len) ((len) == 0)
 
 	if (has_dos_drive_prefix(path))
 		return 0;
@@ -973,8 +980,7 @@ int verify_path(const char *path, unsigned mode)
 			return 1;
 		if (is_dir_sep(c)) {
 inside:
-			if (protect_hfs) {
-
+			if (protect_hfs && is_root(path - orig_path)) {
 				if (is_hfs_dotgit(path))
 					return 0;
 				if (S_ISLNK(mode)) {
@@ -982,11 +988,7 @@ int verify_path(const char *path, unsigned mode)
 						return 0;
 				}
 			}
-			if (protect_ntfs) {
-#ifdef GIT_WINDOWS_NATIVE
-				if (c == '\\')
-					return 0;
-#endif
+			if (protect_ntfs && is_root(path - orig_path)) {
 				if (is_ntfs_dotgit(path))
 					return 0;
 				if (S_ISLNK(mode)) {
@@ -995,11 +997,20 @@ int verify_path(const char *path, unsigned mode)
 				}
 			}
 
+#ifdef GIT_WINDOWS_NATIVE
+			if (protect_ntfs && c == '\\')
+				return 0;
+#endif
+
 			c = *path++;
 			if ((c == '.' && !verify_dotfile(path, mode)) ||
 			    is_dir_sep(c) || c == '\0')
 				return 0;
-		} else if (c == '\\' && protect_ntfs) {
+			if (c == '.' && is_root(path - orig_path -1) &&
+			    !verify_dotgit(path, mode))
+				return 0;
+		} else if (c == '\\' && protect_ntfs &&
+			   is_root(path - orig_path)) {
 			if (is_ntfs_dotgit(path))
 				return 0;
 			if (S_ISLNK(mode)) {
-- 
2.28.0.217.ge805fe7219