NAME
cap_ioctls_limit,
cap_ioctls_get —
manage allowed ioctl
commands
LIBRARY
library “libc”
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 theCAP_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. Including an element that has
been previously revoked will generate an error. After a successful call only
those listed in the array may be used.
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 will not 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
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.