!519 fix create mtab bug to use lstat

Merge pull request !519 from gaohuatao/ci_master

src/cutils/utils_file.c

@@ -51,6 +51,24 @@ bool util_dir_exists(const char *path)
     return S_ISDIR(s.st_mode);
 }
 
+// This function is identical to "util_file_exists",except that if f is a symbolic file, return true
+bool util_fileself_exists(const char *f)
+{
+    struct stat buf;
+    int nret;
+
+    if (f == NULL) {
+        return false;
+    }
+
+    nret = lstat(f, &buf);
+    if (nret < 0) {
+        return false;
+    }
+    return true;
+}
+
+// When f is a symbolic file, if the file that it refers to not exits ,return false
 bool util_file_exists(const char *f)
 {
     struct stat buf;

src/cutils/utils_file.h

@@ -27,6 +27,8 @@ extern "C" {
 
 bool util_dir_exists(const char *path);
 
+bool util_fileself_exists(const char *f);
+
 bool util_file_exists(const char *f);
 
 int util_path_remove(const char *path);

src/services/execution/execute/execution.c

@@ -822,7 +822,7 @@ static int create_mtab_link(const oci_runtime_spec *oci_spec)
         WARN("Failed to delete \"%s\": %s", dir, strerror(errno));
     }
 
-    if (util_file_exists(slink)) {
+    if (util_fileself_exists(slink)) {
         goto out;
     }