linux: Add move_mount

It was added on Linux 5.2 (2db154b3ea8e14b04fee23e3fdfd5e9d17fbc6ae)
as way t move a mount from one place to another and, in the next
commit, allow to attach an unattached mount tree.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>

NEWS

@@ -41,10 +41,10 @@ Major new features:
   have adverse impact.  It is incompatible with EDNS0 usage and DNSSEC
   validation by applications.
 
-* On Linux, the fsopen and fsmount functions have been added.  They are part
+* On Linux, the fsopen, fsmount, and move_mount functions have been added.
-  of the new Linux kernel mount APIs that allow applications to more flexibly
+  They are part of the new Linux kernel mount APIs that allow applications
-  configure and operate on filesystem mounts.  The new mount APIs are
+  to more flexibly configure and operate on filesystem mounts.  The new
-  specifically designed to work with namespaces.
+  mount APIs are specifically designed to work with namespaces.
 
 Deprecated and removed features, and other changes affecting compatibility:
 

sysdeps/unix/sysv/linux/Versions

@@ -302,6 +302,7 @@ libc {
   GLIBC_2.36 {
     fsmount;
     fsopen;
+    move_mount;
     pidfd_open;
     pidfd_getfd;
     pidfd_send_signal;

sysdeps/unix/sysv/linux/aarch64/libc.abilist

@@ -2618,6 +2618,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/alpha/libc.abilist

@@ -2715,6 +2715,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/arc/libc.abilist

@@ -2379,6 +2379,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/arm/be/libc.abilist

@@ -498,6 +498,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/arm/le/libc.abilist

@@ -495,6 +495,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/csky/libc.abilist

@@ -2654,6 +2654,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/hppa/libc.abilist

@@ -2603,6 +2603,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/i386/libc.abilist

@@ -2787,6 +2787,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/ia64/libc.abilist

@@ -2553,6 +2553,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist

@@ -499,6 +499,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist

@@ -2730,6 +2730,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/microblaze/be/libc.abilist

@@ -2703,6 +2703,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/microblaze/le/libc.abilist

@@ -2700,6 +2700,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist

@@ -2695,6 +2695,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist

@@ -2693,6 +2693,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist

@@ -2701,6 +2701,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist

@@ -2604,6 +2604,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/nios2/libc.abilist

@@ -2742,6 +2742,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/or1k/libc.abilist

@@ -2125,6 +2125,7 @@ GLIBC_2.35 writev F
 GLIBC_2.35 wscanf F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist

@@ -2757,6 +2757,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist

@@ -2790,6 +2790,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist

@@ -2512,6 +2512,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist

@@ -2814,6 +2814,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist

@@ -2381,6 +2381,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist

@@ -2581,6 +2581,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist

@@ -2755,6 +2755,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist

@@ -2549,6 +2549,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/sh/be/libc.abilist

@@ -2610,6 +2610,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/sh/le/libc.abilist

@@ -2607,6 +2607,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist

@@ -2750,6 +2750,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist

@@ -2576,6 +2576,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/sys/mount.h

@@ -154,6 +154,16 @@ enum
 #define MOUNT_ATTR_NOSYMFOLLOW  0x00200000 /* Do not follow symlinks.  */
 
 
+/* move_mount flags.  */
+#define MOVE_MOUNT_F_SYMLINKS   0x00000001 /* Follow symlinks on from path */
+#define MOVE_MOUNT_F_AUTOMOUNTS 0x00000002 /* Follow automounts on from path */
+#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
+#define MOVE_MOUNT_T_SYMLINKS   0x00000010 /* Follow symlinks on to path */
+#define MOVE_MOUNT_T_AUTOMOUNTS 0x00000020 /* Follow automounts on to path */
+#define MOVE_MOUNT_T_EMPTY_PATH 0x00000040 /* Empty to path permitted */
+#define MOVE_MOUNT_SET_GROUP    0x00000100 /* Set sharing group instead */
+
+
 __BEGIN_DECLS
 
 /* Mount a filesystem.  */
@@ -176,6 +186,13 @@ extern int fsopen (const char *__fs_name, unsigned int __flags) __THROW;
 extern int fsmount (int __fd, unsigned int __flags,
 		    unsigned int __ms_flags) __THROW;
 
+/* Add the mounted FROM_DFD referenced by FROM_PATHNAME filesystem returned
+   by fsmount in the hierarchy in the place TO_DFD reference by TO_PATHNAME
+   using FLAGS.  */
+extern int move_mount (int __from_dfd, const char *__from_pathname,
+		       int __to_dfd, const char *__to_pathname,
+		       unsigned int flags) __THROW;
+
 __END_DECLS
 
 #endif /* _SYS_MOUNT_H */

sysdeps/unix/sysv/linux/syscalls.list

@@ -37,6 +37,7 @@ mincore		-	mincore		i:aUV	mincore
 mlock		-	mlock		i:bU	mlock
 mlockall	-	mlockall	i:i	mlockall
 mount		EXTRA	mount		i:sssUp	__mount	mount
+move_mount	EXTRA	move_mount	i:isisU	move_mount
 munlock		-	munlock		i:aU	munlock
 munlockall	-	munlockall	i:	munlockall
 nfsservctl	EXTRA	nfsservctl	i:ipp	__compat_nfsservctl	nfsservctl@GLIBC_2.0:GLIBC_2.28

sysdeps/unix/sysv/linux/tst-mount-consts.py

@@ -51,7 +51,9 @@ def main():
 
     status = max(
         check('FSOPEN_.*'),
-        check('FSMOUNT_.*'))
+        check('FSMOUNT_.*'),
+        # MOVE_MOUNT__MASK may vary depending of the kernel version.
+        check('MOVE_MOUNT_.*', 'MOVE_MOUNT__MASK'))
     sys.exit(status)
 
 if __name__ == '__main__':

sysdeps/unix/sysv/linux/x86_64/64/libc.abilist

@@ -2527,6 +2527,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F

sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist

@@ -2633,6 +2633,7 @@ GLIBC_2.35 epoll_pwait2 F
 GLIBC_2.35 posix_spawn_file_actions_addtcsetpgrp_np F
 GLIBC_2.36 fsmount F
 GLIBC_2.36 fsopen F
+GLIBC_2.36 move_mount F
 GLIBC_2.36 pidfd_getfd F
 GLIBC_2.36 pidfd_open F
 GLIBC_2.36 pidfd_send_signal F