mount_utils: add support for mount_setattr() syscall

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/configure.ac b/configure.ac
index 64d10eb3d8487dad3c953ae486fb28f0eb15a692..361a9cf8323669b120e72ab4c5bff188916b1559 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -652,8 +652,9 @@ AC_CHECK_HEADER([ifaddrs.h],
 AC_HEADER_MAJOR
 
 # Check for some syscalls functions
-AC_CHECK_FUNCS([setns pivot_root sethostname unshare rand_r confstr faccessat gettid memfd_create move_mount open_tree execveat clone3 fsopen fspick fsconfig fsmount, openat2, close_range, statvfs])
+AC_CHECK_FUNCS([setns pivot_root sethostname unshare rand_r confstr faccessat gettid memfd_create move_mount open_tree execveat clone3 fsopen fspick fsconfig fsmount, openat2, close_range, statvfs, mount_setattr])
 AC_CHECK_TYPES([__aligned_u64], [], [], [[#include <linux/types.h>]])
+AC_CHECK_TYPES([struct mount_attr], [], [], [[#include <linux/mount.h>]])
 AC_CHECK_TYPES([struct open_how], [], [], [[#include <linux/openat2.h>]])
 AC_CHECK_TYPES([struct clone_args], [], [], [[#include <linux/sched.h>]])
 AC_CHECK_MEMBERS([struct clone_args.set_tid],[],[],[[#include <linux/sched.h>]])

diff --git a/src/lxc/mount_utils.h b/src/lxc/mount_utils.h
index d38581d9b11c9d489c2b84e6855ac06403811424..5053ebfea39fbef12529e1b41266fe7cbba79a64 100644 (file)
--- a/src/lxc/mount_utils.h
+++ b/src/lxc/mount_utils.h
@@ -152,6 +152,10 @@
 #define MOUNT_ATTR_NODIRATIME 0x00000080 /* Do not update directory access times */
 #endif
 
+#ifndef MOUNT_ATTR_IDMAP
+#define MOUNT_ATTR_IDMAP 0x00100000
+#endif
+
 __hidden extern int mnt_attributes_new(unsigned int old_flags, unsigned int *new_flags);
 
 __hidden extern int mnt_attributes_old(unsigned int new_flags, unsigned int *old_flags);

diff --git a/src/lxc/syscall_numbers.h b/src/lxc/syscall_numbers.h
index 0bc5efe3d8d234de2525eea342b0be8ec740486d..063316de349a1ce5e77ec780759f9451a50d749d 100644 (file)
--- a/src/lxc/syscall_numbers.h
+++ b/src/lxc/syscall_numbers.h
@@ -680,4 +680,24 @@
        #endif
 #endif
 
+#ifndef __NR_mount_setattr
+       #if defined __alpha__
+               #define __NR_mount_setattr 552
+       #elif defined _MIPS_SIM
+               #if _MIPS_SIM == _MIPS_SIM_ABI32        /* o32 */
+                       #define __NR_mount_setattr (442 + 4000)
+               #endif
+               #if _MIPS_SIM == _MIPS_SIM_NABI32       /* n32 */
+                       #define __NR_mount_setattr (442 + 6000)
+               #endif
+               #if _MIPS_SIM == _MIPS_SIM_ABI64        /* n64 */
+                       #define __NR_mount_setattr (442 + 5000)
+               #endif
+       #elif defined __ia64__
+               #define __NR_mount_setattr (442 + 1024)
+       #else
+               #define __NR_mount_setattr 442
+       #endif
+#endif
+
 #endif /* __LXC_SYSCALL_NUMBERS_H */

diff --git a/src/lxc/syscall_wrappers.h b/src/lxc/syscall_wrappers.h
index c1a861e2f7bf8c3e70b9c17b778ddfc91873c7ab..7188211472c907cd66501fee5cd49b07eda9a890 100644 (file)
--- a/src/lxc/syscall_wrappers.h
+++ b/src/lxc/syscall_wrappers.h
@@ -208,6 +208,24 @@ static inline int fsmount_lxc(int fs_fd, unsigned int flags, unsigned int attr_f
 extern int fsmount(int fs_fd, unsigned int flags, unsigned int attr_flags);
 #endif
 
+/*
+ * mount_setattr()
+ */
+struct lxc_mount_attr {
+       __u64 attr_set;
+       __u64 attr_clr;
+       __u64 propagation;
+       __u64 userns_fd;
+};
+
+#ifndef HAVE_MOUNT_SETATTR
+static inline int mount_setattr(int dfd, const char *path, unsigned int flags,
+                               struct lxc_mount_attr *attr, size_t size)
+{
+       return syscall(__NR_mount_setattr, dfd, path, flags, attr, size);
+}
+#endif
+
 /*
  * Arguments for how openat2(2) should open the target path. If only @flags and
  * @mode are non-zero, then openat2(2) operates very similarly to openat(2).