From c4eef179909147cec0c6ac3e2fa9989b24065fc0 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 5 Mar 2025 00:05:31 +0900
Subject: [PATCH] dirent-util: add several assertions in posix_getdents()

Follow-up for e86a492ff08526e5adf85fa881c76f80adc3c84a.
---
 src/basic/dirent-util.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/basic/dirent-util.h b/src/basic/dirent-util.h
index 816b28e04f..f3007b6bc3 100644
--- a/src/basic/dirent-util.h
+++ b/src/basic/dirent-util.h
@@ -34,6 +34,13 @@ struct dirent *readdir_no_dot(DIR *dirp);
  * Let's introduce a simple wrapper. */
 #if !HAVE_POSIX_GETDENTS
 static inline ssize_t posix_getdents(int fd, void *buf, size_t nbyte, int flags) {
+        assert(fd >= 0);
+        assert(buf);
+        assert(nbyte > 0);
+
+        if (flags != 0)
+                return -EINVAL; /* Currently flags must be zero. */
+
         return getdents64(fd, buf, nbyte);
 }
 #endif