syscalls: add fsmount()

configure.ac

@@ -622,7 +622,7 @@ 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])
+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])
 AC_CHECK_TYPES([struct clone_args], [], [], [[#include <linux/sched.h>]])
 AC_CHECK_MEMBERS([struct clone_args.set_tid],[],[],[[#include <linux/sched.h>]])
 AC_CHECK_MEMBERS([struct clone_args.cgroup],[],[],[[#include <linux/sched.h>]])

src/lxc/syscall_numbers.h

@@ -623,4 +623,24 @@
 	#endif
 #endif
 
+#ifndef __NR_fsmount
+	#if defined __alpha__
+		#define __NR_fsmount 542
+	#elif defined _MIPS_SIM
+		#if _MIPS_SIM == _MIPS_SIM_ABI32	/* o32 */
+			#define __NR_fsmount 4432
+		#endif
+		#if _MIPS_SIM == _MIPS_SIM_NABI32	/* n32 */
+			#define __NR_fsmount 6432
+		#endif
+		#if _MIPS_SIM == _MIPS_SIM_ABI64	/* n64 */
+			#define __NR_fsmount 5432
+		#endif
+	#elif defined __ia64__
+		#define __NR_fsmount (432 + 1024)
+	#else
+		#define __NR_fsmount 432
+	#endif
+#endif
+
 #endif /* __LXC_SYSCALL_NUMBERS_H */

src/lxc/syscall_wrappers.h

@@ -191,4 +191,14 @@ static inline int fsconfig_lxc(int fd, unsigned int cmd, const char *key, const
 extern int fsconfig(int fd, unsigned int cmd, const char *key, const void *value, int aux);
 #endif
 
+#ifndef HAVE_FSMOUNT
+static inline int fsmount_lxc(int fs_fd, unsigned int flags, unsigned int attr_flags)
+{
+	return syscall(__NR_fsmount, fs_fd, flags, attr_flags);
+}
+#define fsmount fsmount_lxc
+#else
+extern int fsmount(int fs_fd, unsigned int flags, unsigned int attr_flags);
+#endif
+
 #endif /* __LXC_SYSCALL_WRAPPER_H */