From 84e8edec308dd157a013c811c3fa351fc0340f63 Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 27 Apr 2021 14:16:06 +0200
Subject: [PATCH] missing: add syscall wrappers for new mount API

---
 meson.build                 |  6 +++
 src/basic/missing_syscall.h | 95 +++++++++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/meson.build b/meson.build
index 93d3c26a22..f30b7eef79 100644
--- a/meson.build
+++ b/meson.build
@@ -480,11 +480,14 @@ conf.set('SIZEOF_RLIM_T', cc.sizeof('rlim_t', prefix : '#include <sys/resource.h
 
 decl_headers = '''
 #include <uchar.h>
+#include <sys/mount.h>
 #include <sys/stat.h>
+#include <linux/fs.h>
 '''
 
 foreach decl : ['char16_t',
                 'char32_t',
+                'struct mount_attr',
                 'struct statx',
                ]
 
@@ -555,6 +558,9 @@ foreach ident : [
         ['execveat',          '''#include <unistd.h>'''],
         ['close_range',       '''#include <unistd.h>'''],
         ['epoll_pwait2',      '''#include <sys/epoll.h>'''],
+        ['mount_setattr',     '''#include <sys/mount.h>'''],
+        ['move_mount',        '''#include <sys/mount.h>'''],
+        ['open_tree',         '''#include <sys/mount.h>'''],
 ]
 
         have = cc.has_function(ident[0], prefix : ident[1], args : '-D_GNU_SOURCE')
diff --git a/src/basic/missing_syscall.h b/src/basic/missing_syscall.h
index 1384324804..9e3a165857 100644
--- a/src/basic/missing_syscall.h
+++ b/src/basic/missing_syscall.h
@@ -425,3 +425,98 @@ static inline int missing_epoll_pwait2(
 
 #  define epoll_pwait2 missing_epoll_pwait2
 #endif
+
+/* ======================================================================= */
+
+#if !HAVE_MOUNT_SETATTR
+
+#if !HAVE_STRUCT_MOUNT_ATTR
+struct mount_attr {
+        uint64_t attr_set;
+        uint64_t attr_clr;
+        uint64_t propagation;
+        uint64_t userns_fd;
+};
+#else
+struct mount_attr;
+#endif
+
+#ifndef MOUNT_ATTR_IDMAP
+#define MOUNT_ATTR_IDMAP 0x00100000
+#endif
+
+#ifndef AT_RECURSIVE
+#define AT_RECURSIVE 0x8000
+#endif
+
+static inline int missing_mount_setattr(
+                int dfd,
+                const char *path,
+                unsigned flags,
+                struct mount_attr *attr,
+                size_t size) {
+
+#  if defined __NR_mount_setattr && __NR_mount_setattr >= 0
+        return syscall(__NR_mount_setattr, dfd, path, flags, attr, size);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+
+#  define mount_setattr missing_mount_setattr
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_OPEN_TREE
+
+#ifndef OPEN_TREE_CLONE
+#define OPEN_TREE_CLONE 1
+#endif
+
+#ifndef OPEN_TREE_CLOEXEC
+#define OPEN_TREE_CLOEXEC O_CLOEXEC
+#endif
+
+static inline int missing_open_tree(
+                int dfd,
+                const char *filename,
+                unsigned flags) {
+
+#  if defined __NR_open_tree && __NR_open_tree >= 0
+        return syscall(__NR_open_tree, dfd, filename, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+
+#  define open_tree missing_open_tree
+#endif
+
+/* ======================================================================= */
+
+#if !HAVE_MOVE_MOUNT
+
+#ifndef MOVE_MOUNT_F_EMPTY_PATH
+#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
+#endif
+
+static inline int missing_move_mount(
+                int from_dfd,
+                const char *from_pathname,
+                int to_dfd,
+                const char *to_pathname,
+                unsigned flags) {
+
+#  if defined __NR_move_mount && __NR_move_mount >= 0
+        return syscall(__NR_move_mount, from_dfd, from_pathname, to_dfd, to_pathname, flags);
+#  else
+        errno = ENOSYS;
+        return -1;
+#  endif
+}
+
+#  define move_mount missing_move_mount
+#endif