From 34a9da0d8e04626e4fec1f076e814d633d149a58 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 7 Mar 2023 14:36:03 +0100
Subject: [PATCH] missing: add fsmount() syscall fallback definition

---
 meson.build                 |  1 +
 src/basic/missing_syscall.h | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/meson.build b/meson.build
index 6885884a00..4a59784536 100644
--- a/meson.build
+++ b/meson.build
@@ -629,6 +629,7 @@ foreach ident : [
         ['open_tree',         '''#include <sys/mount.h>'''],
         ['fsopen',            '''#include <sys/mount.h>'''],
         ['fsconfig',          '''#include <sys/mount.h>'''],
+        ['fsmount',           '''#include <sys/mount.h>'''],
         ['getdents64',        '''#include <dirent.h>'''],
 ]
 
diff --git a/src/basic/missing_syscall.h b/src/basic/missing_syscall.h
index 98cd037962..3d66ab7d7a 100644
--- a/src/basic/missing_syscall.h
+++ b/src/basic/missing_syscall.h
@@ -609,6 +609,26 @@ static inline int missing_fsconfig(int fd, unsigned cmd, const char *key, const
 
 /* ======================================================================= */
 
+#if !HAVE_FSMOUNT
+
+#ifndef FSMOUNT_CLOEXEC
+#define FSMOUNT_CLOEXEC 0x00000001
+#endif
+
+static inline int missing_fsmount(int fd, unsigned flags, unsigned ms_flags) {
+#  if defined __NR_fsmount && __NR_fsmount >= 0
+        return syscall(__NR_fsmount, fd, flags, ms_flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+
+#  define fsmount missing_fsmount
+#endif
+
+/* ======================================================================= */
+
 #if !HAVE_GETDENTS64
 
 static inline ssize_t missing_getdents64(int fd, void *buffer, size_t length) {