freebsd man page for cap_ioctls_limit

CAP_IOCTLS_LIMIT(2)					      BSD System Calls Manual					       CAP_IOCTLS_LIMIT(2)

NAME
     cap_ioctls_limit, cap_ioctls_get -- manage allowed ioctl commands

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <sys/capsicum.h>

     int
     cap_ioctls_limit(int fd, const unsigned long *cmds, size_t ncmds);

     ssize_t
     cap_ioctls_get(int fd, unsigned long *cmds, size_t maxcmds);

DESCRIPTION
     If a file descriptor is granted the CAP_IOCTL capability right, the list of allowed ioctl(2) commands can be selectively reduced (but never
     expanded) with the cap_ioctls_limit() system call.  The cmds argument is an array of ioctl(2) commands and the ncmds argument specifies the
     number of elements in the array.  There can be up to 256 elements in the array.

     The list of allowed ioctl commands for a given file descriptor can be obtained with the cap_ioctls_get() system call.  The cmds argument
     points at memory that can hold up to maxcmds values.  The function populates the provided buffer with up to maxcmds elements, but always
     returns the total number of ioctl commands allowed for the given file descriptor.	The total number of ioctls commands for the given file
     descriptor can be obtained by passing NULL as the cmds argument and 0 as the maxcmds argument.  If all ioctl commands are allowed (CAP_IOCTL
     capability right is assigned to the file descriptor and the cap_ioctls_limit() system call was never called for this file descriptor), the
     cap_ioctls_get() system call will return CAP_IOCTLS_ALL and won't modify the buffer pointed to by the cmds argument.

RETURN VALUES
     The cap_ioctls_limit() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to
     indicate the error.

     The cap_ioctls_get() function, if successful, returns the total number of allowed ioctl commands or the value CAP_IOCTLS_ALL if all ioctls
     commands are allowed.  On failure the value -1 is returned and the global variable errno is set to indicate the error.

ERRORS
     cap_ioctls_limit() succeeds unless:

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

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

     [EINVAL]		The ncmds argument is greater than 256.

     [ENOTCAPABLE]	cmds would expand the list of allowed ioctl(2) commands.

     cap_ioctls_get() succeeds unless:

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

     [EFAULT]		The cmds argument points at invalid address.

SEE ALSO
     cap_fcntls_limit(2), cap_rights_limit(2), ioctl(2)

HISTORY
     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.

BSD
								  March 27, 2014							       BSD