syscalls: add close_range()

configure.ac

@@ -644,7 +644,7 @@ 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 fsmount, openat2])
+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])
 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>]])

src/lxc/syscall_numbers.h

@@ -660,4 +660,24 @@
 	#endif
 #endif
 
+#ifndef __NR_close_range
+	#if defined __alpha__
+		#define __NR_close_range 546
+	#elif defined _MIPS_SIM
+		#if _MIPS_SIM == _MIPS_SIM_ABI32	/* o32 */
+			#define __NR_close_range (436 + 4000)
+		#endif
+		#if _MIPS_SIM == _MIPS_SIM_NABI32	/* n32 */
+			#define __NR_close_range (436 + 6000)
+		#endif
+		#if _MIPS_SIM == _MIPS_SIM_ABI64	/* n64 */
+			#define __NR_close_range (436 + 5000)
+		#endif
+	#elif defined __ia64__
+		#define __NR_close_range (436 + 1024)
+	#else
+		#define __NR_close_range 436
+	#endif
+#endif
+
 #endif /* __LXC_SYSCALL_NUMBERS_H */

src/lxc/syscall_wrappers.h

@@ -282,4 +282,19 @@ static inline int openat2(int dfd, const char *filename, struct lxc_open_how *ho
 }
 #endif /* HAVE_OPENAT2 */
 
+#ifndef CLOSE_RANGE_UNSHARE
+#define CLOSE_RANGE_UNSHARE	(1U << 1)
+#endif
+
+#ifndef CLOSE_RANGE_CLOEXEC
+#define CLOSE_RANGE_CLOEXEC	(1U << 2)
+#endif
+
+#ifndef HAVE_CLOSE_RANGE
+static inline int close_range(unsigned int fd, unsigned int max_fd, unsigned int flags)
+{
+	return syscall(__NR_close_range, fd, max_fd, flags);
+}
+#endif
+
 #endif /* __LXC_SYSCALL_WRAPPER_H */