ENOSYS(1)   <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>  ENOSYS(1)

<?><?><?><?><?>
       enosys - <?><?><?><?><?><?><?><?><?><?> <?><?><?>
       <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?> <?> <?><?><?><?><?>
       ENOSYS

<?><?><?><?><?><?><?><?> <?><?><?><?>
       enosys [--syscall|-s <?><?><?><?><?><?><?><?><?>-<?><?><?><?><?><?>]
       <?><?><?><?><?><?><?>

<?><?><?><?>
       enosys is a simple command to execute a child process for which certain
       syscalls fail with errno ENOSYS.

       It can be used to test the behavior of applications in the face of
       missing syscalls as would happen when running on old kernels.

<?><?><?><?><?><?><?><?><?>
       -s, --syscall
           Syscall to block with ENOSYS. Can be specified multiple times. An
           alternative error number or name can be specified with a colon.

       -i, --ioctl
           Ioctl to block with ENOTTY. Can be specified multiple times. An
           alternative error number or name can be specified with a colon.

       -l, --list
           <?><?><?><?><?><?><?> <?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>, <?><?><?>
           <?><?><?><?><?><?> enosys.

       -m, --list-ioctl
           <?><?><?><?><?><?><?> <?><?><?><?><?><?> ioctl, <?><?><?>
           <?><?><?><?><?><?> enosys.

       -d, --dump[=<?><?><?><?>]
           <?><?><?><?><?><?><?> <?><?><?><?> <?><?><?><?><?><?><?>
           <?><?><?><?>-<?><?><?><?><?> seccomp <?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>.

           The dump can for example be used by setpriv --seccomp-filter.

       -h, --help
           <?><?><?><?><?><?><?> <?><?><?><?><?> <?><?><?><?><?><?><?> <?>
           <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>.

       -V, --version
           <?><?><?><?><?><?><?><?> <?><?><?><?> <?><?><?><?>
           <?><?><?><?><?><?> <?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?>.

<?><?><?><?><?><?><?><?>
           # fail syscall "fallocate" with ENOSYS
           enosys -s fallocate ...

           # fail syscall "fallocate" with ENOMEM
           enosys -s fallocate:ENOMEM ...

           # fail syscall "fallocate" with value 12/ENOMEM
           enosys -s fallocate:12 ...

           # fail ioctl FIOCLEX with ENOTTY
           enosys -i FIOCLEX ...

           # fail ioctl FIOCLEX with ENOMEM
           enosys -i FIOCLEX:ENOMEM ...

           # <?><?><?><?><?> <?> <?><?><?><?><?><?><?><?> <?><?><?> ioctl FIOCLEX <?><?> <?><?><?><?><?><?><?><?><?> 12/ENOMEM
           enosys -i FIOCLEX:12 ...

<?><?><?><?> <?><?><?><?><?><?>
       enosys exits with the status code of the executed process. The
       following values have special meanings:

       1
           <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>

       2
           <?><?><?><?><?><?><?> <?><?> <?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?>

<?><?><?><?><?><?>
       Thomas Weissschuh <thomas@t-8ch.de>

<?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       syscall(2)

<?><?> <?><?><?><?><?><?><?><?><?> <?><?><?><?> <?><?><?> <?><?><?><?>
       <?><?><?> <?><?><?><?><?><?><?><?><?><?> <?><?><?><?> <?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?> <?><?><?><?><?><?>
       <https://github.com/util-linux/util-linux/issues>

<?><?><?><?><?><?> <?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> enosys <?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?> util-linux, <?><?><?><?> <?><?><?><?><?>
       <?><?><?><?><?><?><?><?> <?> <?><?><?><?><?><?> <?><?><?><?> Linux
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.41                   2025-03-29                         ENOSYS(1)