From: Mike Yuan <me@yhndnzj.com>
Date: Mon, 20 May 2024 11:33:26 +0000 (+0800)
Subject: fs-util: try AT_EMPTY_PATH for access_fd() first
X-Git-Tag: v257-rc1~1193^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F32933%2Fhead;p=thirdparty%2Fsystemd.git

fs-util: try AT_EMPTY_PATH for access_fd() first
---

diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index 6df53cb0c4c..92ceb3b352e 100644
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -675,6 +675,14 @@ int access_fd(int fd, int mode) {
 
         /* Like access() but operates on an already open fd */
 
+        if (faccessat(fd, "", mode, AT_EMPTY_PATH) >= 0)
+                return 0;
+        if (errno != EINVAL)
+                return -errno;
+
+        /* Support for AT_EMPTY_PATH is added rather late (kernel 5.8), so fall back to going through /proc/
+         * if unavailable. */
+
         if (access(FORMAT_PROC_FD_PATH(fd), mode) < 0) {
                 if (errno != ENOENT)
                         return -errno;