NAME

       cap_fcntls_limit, cap_fcntls_get — manage allowed fcntl commands

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <sys/capsicum.h>

       int
       cap_fcntls_limit(int fd, uint32_t fcntlrights);

       int
       cap_fcntls_get(int fd, uint32_t *fcntlrightsp);

DESCRIPTION

       If a file descriptor is granted the CAP_FCNTL capability right, the list of allowed fcntl(2) commands can
       be selectively reduced (but never expanded) with the cap_fcntls_limit() system call.

       A   bitmask  of  allowed  fcntls  commands  for  a  given  file  descriptor  can  be  obtained  with  the
       cap_fcntls_get() system call.

FLAGS

       The following flags may be specified  in  the  fcntlrights  argument  or  returned  in  the  fcntlrightsp
       argument:

       CAP_FCNTL_GETFL   Permit F_GETFL command.

       CAP_FCNTL_SETFL   Permit F_SETFL command.

       CAP_FCNTL_GETOWN  Permit F_GETOWN command.

       CAP_FCNTL_SETOWN  Permit F_SETOWN command.

RETURN VALUES

       Upon  successful  completion,  the value 0 is returned; otherwise the value -1 is returned and the global
       variable errno is set to indicate the error.

ERRORS

       cap_fcntls_limit() succeeds unless:

       [EBADF]            The fd argument is not a valid descriptor.

       [EINVAL]           An invalid flag has been passed in fcntlrights.

       [ENOTCAPABLE]      fcntlrights would expand the list of allowed fcntl(2) commands.

       cap_fcntls_get() succeeds unless:

       [EBADF]            The fd argument is not a valid descriptor.

       [EFAULT]           The fcntlrightsp argument points at an invalid address.

SEE ALSO

       cap_ioctls_limit(2), cap_rights_limit(2), fcntl(2)

HISTORY

       The cap_fcntls_get() and cap_fcntls_limit() system calls first appeared  in  FreeBSD  8.3.   Support  for
       capabilities and capabilities mode was developed as part of the TrustedBSD Project.

AUTHORS

       This  function  was  created  by Pawel Jakub Dawidek <pawel@dawidek.net> under sponsorship of the FreeBSD
       Foundation.

Debian                                             May 5, 2020                               CAP_FCNTLS_LIMIT(2)