From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 28 Feb 2025 10:28:33 +0000 (+0900)
Subject: mountpoint-util: make statx() failure critical
X-Git-Tag: v258-rc1~1216^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ee739ea6929a5ca58a0fcf0cb7d3b274e9a5f4c1;p=thirdparty%2Fsystemd.git

mountpoint-util: make statx() failure critical

Two error conditions are unreachable, as now both glibc and kernel
support statx(). In other many places, failure in statx() are handled as
critical, even if it is filtered by seccomp or so. Let's follow the same
way here.
---

diff --git a/src/basic/mountpoint-util.c b/src/basic/mountpoint-util.c
index e59a748df03..cb79d621a1f 100644
--- a/src/basic/mountpoint-util.c
+++ b/src/basic/mountpoint-util.c
@@ -223,9 +223,9 @@ int is_mount_point_at(int fd, const char *filename, int flags) {
                         filename = ".";
                 else {
                         /* If the file name is empty we'll see if the specified 'fd' is a mount point.
-                         * That's only supported if the kernel supports statx(), or if the inode specified
-                         * via 'fd' refers to a directory. Otherwise, we'll have to fail (ENOTDIR), because
-                         * we have no kernel API to query the information we need. */
+                         * That's only supported by statx(), or if the inode specified via 'fd' refers to a
+                         * directory. Otherwise, we'll have to fail (ENOTDIR), because we have no kernel API
+                         * to query the information we need. */
                         flags |= AT_EMPTY_PATH;
                         filename = "";
                 }
@@ -266,14 +266,10 @@ int is_mount_point_at(int fd, const char *filename, int flags) {
                   AT_NO_AUTOMOUNT |            /* don't trigger automounts – mounts are a local concept, hence no need to trigger automounts to determine STATX_ATTR_MOUNT_ROOT */
                   AT_STATX_DONT_SYNC,          /* don't go to the network for this – for similar reasons */
                   STATX_TYPE,
-                  &sx) < 0) {
-                if (!ERRNO_IS_NOT_SUPPORTED(errno) && /* statx() is not supported by the kernel. */
-                    !ERRNO_IS_PRIVILEGE(errno) &&     /* maybe filtered by seccomp. */
-                    errno != EINVAL)                  /* glibc's fallback method returns EINVAL when AT_STATX_DONT_SYNC is set. */
-                        return -errno;
+                  &sx) < 0)
+                return -errno;
 
-                /* If statx() is not available or forbidden, fall back to name_to_handle_at() below */
-        } else if (FLAGS_SET(sx.stx_attributes_mask, STATX_ATTR_MOUNT_ROOT)) /* yay! */
+        if (FLAGS_SET(sx.stx_attributes_mask, STATX_ATTR_MOUNT_ROOT)) /* yay! */
                 return FLAGS_SET(sx.stx_attributes, STATX_ATTR_MOUNT_ROOT);
 
         _cleanup_free_ struct file_handle *h = NULL, *h_parent = NULL;
@@ -410,16 +406,10 @@ int path_get_mnt_id_at(int dir_fd, const char *path, int *ret) {
                   AT_NO_AUTOMOUNT |    /* don't trigger automounts, mnt_id is a local concept */
                   AT_STATX_DONT_SYNC,  /* don't go to the network, mnt_id is a local concept */
                   STATX_MNT_ID,
-                  &sx) < 0) {
-                if (!ERRNO_IS_NOT_SUPPORTED(errno) && /* statx() is not supported by the kernel. */
-                    !ERRNO_IS_PRIVILEGE(errno) &&     /* maybe filtered by seccomp. */
-                    errno != EINVAL)                  /* glibc's fallback method returns EINVAL when AT_STATX_DONT_SYNC is set. */
-                        return -errno;
-
-                /* Fall back to name_to_handle_at() and then fdinfo if statx is not supported or we lack
-                 * privileges */
+                  &sx) < 0)
+                return -errno;
 
-        } else if (FLAGS_SET(sx.stx_mask, STATX_MNT_ID)) {
+        if (FLAGS_SET(sx.stx_mask, STATX_MNT_ID)) {
                 *ret = sx.stx_mnt_id;
                 return 0;
         }