Support mount_setattr syscall

src/syscalls.py

@@ -1734,7 +1734,7 @@ def __init__(self, **kwargs):
 pidfd_getfd = EmulatedSyscall(all=438)
 process_madvise = UnsupportedSyscall(all=440)
 epoll_pwait2 = IrregularEmulatedSyscall(all=441)
-mount_setattr = UnsupportedSyscall(all=442)
+mount_setattr = EmulatedSyscall(all=442)
 quotactl_fd = UnsupportedSyscall(all=443)
 landlock_create_ruleset = EmulatedSyscall(all=444)
 landlock_add_rule = EmulatedSyscall(all=445)

src/test/fsmount.c

@@ -3,6 +3,8 @@
 #include "nsutils.h"
 #include "util.h"
 
+#include <sys/mount.h>
+
 int main(void) {
   if (try_setup_ns(CLONE_NEWNS) < 0) {
     atomic_puts("EXIT-SUCCESS");
@@ -21,6 +23,11 @@ int main(void) {
   ret = syscall(RR_move_mount, mnt_fd, "", AT_FDCWD, "/tmp", MOVE_MOUNT_F_EMPTY_PATH);
   test_assert(ret == 0);
 
+  struct mount_attr attr;
+  memset(&attr, 0, sizeof(attr));
+  ret = syscall(RR_mount_setattr, mnt_fd, "", AT_EMPTY_PATH, &attr, sizeof(attr));
+  test_assert(ret == 0);
+
   atomic_puts("EXIT-SUCCESS");
   return 0;
 }