From f25bff5eaf6881717e873f27c26f2e8264517c16 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Fri, 25 Sep 2020 16:40:02 +0200
Subject: [PATCH] fs-util: add new futimens_opath() helper

futimens() that works for O_PATH fds.
---
 src/basic/fs-util.c | 19 +++++++++++++++++++
 src/basic/fs-util.h |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/src/basic/fs-util.c b/src/basic/fs-util.c
index c20a29332a..587b3504ee 100644
--- a/src/basic/fs-util.c
+++ b/src/basic/fs-util.c
@@ -312,6 +312,25 @@ int fchmod_opath(int fd, mode_t m) {
         return 0;
 }
 
+int futimens_opath(int fd, const struct timespec ts[2]) {
+        char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
+
+        /* Similar to fchmod_path() but for futimens() */
+
+        xsprintf(procfs_path, "/proc/self/fd/%i", fd);
+        if (utimensat(AT_FDCWD, procfs_path, ts, 0) < 0) {
+                if (errno != ENOENT)
+                        return -errno;
+
+                if (proc_mounted() == 0)
+                        return -ENOSYS; /* if we have no /proc/, the concept is not implementable */
+
+                return -ENOENT;
+        }
+
+        return 0;
+}
+
 int stat_warn_permissions(const char *path, const struct stat *st) {
         assert(path);
         assert(st);
diff --git a/src/basic/fs-util.h b/src/basic/fs-util.h
index eb6e1eee4f..cf87a1e4d5 100644
--- a/src/basic/fs-util.h
+++ b/src/basic/fs-util.h
@@ -38,6 +38,8 @@ int fchmod_and_chown(int fd, mode_t mode, uid_t uid, gid_t gid);
 int fchmod_umask(int fd, mode_t mode);
 int fchmod_opath(int fd, mode_t m);
 
+int futimens_opath(int fd, const struct timespec ts[2]);
+
 int fd_warn_permissions(const char *path, int fd);
 int stat_warn_permissions(const char *path, const struct stat *st);
 
-- 
2.25.1