[PATCH] erofs-utils : Fail the image creation when source path is not a directory file.

[Pratik Shinde]

In the erofs.mkfs utility, if the source path is not a directory,image
creation should not proceed.since root of the filesystem needs to be a directory.

In the erofs kernel code, we return error in case root inode(read from disk) is not
a directory.But the mkfs utility lets you create an image based on Regular file
(S_IFREG) too.

Signed-off-by: Pratik Shinde <pratikshinde320 at gmail.com>
---
 mkfs/main.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/mkfs/main.c b/mkfs/main.c
index 93cacca..e72b9e2 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -12,6 +12,7 @@
 #include <stdlib.h>
 #include <limits.h>
 #include <libgen.h>
+#include <sys/stat.h>
 #include "erofs/config.h"
 #include "erofs/print.h"
 #include "erofs/cache.h"
@@ -76,8 +77,8 @@ static int parse_extended_opts(const char *opts)
 
 static int mkfs_parse_options_cfg(int argc, char *argv[])
 {
-	int opt, i;
-
+	int opt, i, ret;
+	struct stat64 st;
 	while ((opt = getopt(argc, argv, "d:z:E:")) != -1) {
 		switch (opt) {
 		case 'z':
@@ -135,7 +136,14 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
 			  erofs_strerror(-errno));
 		return -ENOENT;
 	}
-
+	ret = lstat64(cfg.c_src_path, &st);
+	if (ret)
+		return -EINVAL;
+	if ((st.st_mode & S_IFMT) != S_IFDIR) {
+		erofs_err("root of the filesystem is not a directory - %s",
+			  cfg.c_src_path);
+		return -EINVAL;
+	}
 	if (optind < argc) {
 		erofs_err("Unexpected argument: %s\n", argv[optind]);
 		return -EINVAL;
-- 
2.9.3