lkl tools: cpfromfs: fix root directory copy

Currently copying the disk image root is broken:

cptofs -P 1 -t ext4 -i test.img ~/linux /
cpfromfs -P 1 -t ext4 -i test.img / ~/linuxcopy

leads to the following in ~/linuxcopy:

/home/ec2-user/linuxcopy
└── 0000fe01
    ├── linux
        │   ├── arch

The problem is that basename("/mnt/0000fe01/") returns 0000fe01 where
we would expect /.

Fix that by making the root folder copy case special.

Reported-by: Dan Peebles <[email protected]>
Signed-off-by: Octavian Purdila <[email protected]>

tools/lkl/cptofs.c

@@ -480,6 +480,27 @@ static int searchdir(const char *src, const char *dst, const char *match)
 	return ret;
 }
 
+static int match_root(const char *src)
+{
+	const char *c = src;
+
+	while (*c) {
+		switch (*c) {
+		case '.':
+			if (c > src && c[-1] == '.')
+				return 0;
+			break;
+		case '/':
+			break;
+		default:
+			return 0;
+		}
+		c++;
+	}
+
+	return 1;
+}
+
 int copy_one(const char *src, const char *mpoint, const char *dst)
 {
 	char *src_path_dir, *src_path_base;
@@ -493,6 +514,9 @@ int copy_one(const char *src, const char *mpoint, const char *dst)
 		snprintf(dst_path, sizeof(dst_path),  "%s", dst);
 	}
 
+	if (match_root(src))
+		return searchdir(src_path, dst, NULL);
+
 	src_path_dir = dirname(strdup(src_path));
 	src_path_base = basename(strdup(src_path));