CAP_FCNTLS_LIMIT(2)

NAME
cap_fcntls_limit, cap_fcntls_get - manage allowed fcntl commands

LIBRARY
libc

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

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.

[ENOSYS]
    The running kernel was compiled without options CAPABILITY_MODE.

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.