From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 21 Jul 2023 16:23:17 +0000 (+0900)
Subject: fd-util: make path_is_root_at() not fail even when /proc is mounted
X-Git-Tag: v254-rc3~7^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bd96111d5fa8d3c05aad6aed21243d6b0534055d;p=thirdparty%2Fsystemd.git

fd-util: make path_is_root_at() not fail even when /proc is mounted

path_get_mnt_id_at() -> fd_fdinfo_mnt_id() may return -EOPNOTSUPP when
/proc is mounted, and -ENOSYS otherwise, when an old kernel is used.
---

diff --git a/src/basic/fd-util.c b/src/basic/fd-util.c
index d9ef7ec9326..1c67e785aa3 100644
--- a/src/basic/fd-util.c
+++ b/src/basic/fd-util.c
@@ -929,17 +929,18 @@ int path_is_root_at(int dir_fd, const char *path) {
          * $ mount --bind /tmp/x /tmp/x/y
          *
          * Note, statx() does not provide the mount ID and path_get_mnt_id_at() does not work when an old
-         * kernel is used without /proc mounted. In that case, let's assume that we do not have such spurious
-         * mount points in an early boot stage, and silently skip the following check. */
+         * kernel is used. In that case, let's assume that we do not have such spurious mount points in an
+         * early boot stage, and silently skip the following check. */
 
         if (!FLAGS_SET(st.nsx.stx_mask, STATX_MNT_ID)) {
                 int mntid;
 
                 r = path_get_mnt_id_at(dir_fd, "", &mntid);
-                if (r == -ENOSYS)
-                        return true; /* skip the mount ID check */
-                if (r < 0)
+                if (r < 0) {
+                        if (ERRNO_IS_NOT_SUPPORTED(r))
+                                return true; /* skip the mount ID check */
                         return r;
+                }
                 assert(mntid >= 0);
 
                 st.nsx.stx_mnt_id = mntid;
@@ -950,10 +951,11 @@ int path_is_root_at(int dir_fd, const char *path) {
                 int mntid;
 
                 r = path_get_mnt_id_at(dir_fd, "..", &mntid);
-                if (r == -ENOSYS)
-                        return true; /* skip the mount ID check */
-                if (r < 0)
+                if (r < 0) {
+                        if (ERRNO_IS_NOT_SUPPORTED(r))
+                                return true; /* skip the mount ID check */
                         return r;
+                }
                 assert(mntid >= 0);
 
                 pst.nsx.stx_mnt_id = mntid;