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CAP_IOCTLS_LIMIT(2)	       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.  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  ob-
     tained  with the cap_ioctls_get() system call.  The cmds argument points at
     memory that can hold up to maxcmds values.  The function populates the pro-
     vided buffer with up to maxcmds elements, but always returns the total num-
     ber 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 argu-
     ment.

RETURN VALUES
     The cap_ioctls_limit() function returns the value 0 if  successful;  other-
     wise the value -1 is returned and the global variable errno is set to indi-
     cate 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
     The cap_ioctls_limit() and cap_ioctls_get() system calls will fail if:

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

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

     [ENOSYS]		The running kernel was compiled without options CAPABIL-
			ITY_MODE.

     The cap_ioctls_limit() system call may also return the following errors:

     [EINVAL]		The ncmds argument is greater than 256.

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

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

HISTORY
     The cap_ioctls_get() and cap_ioctls_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.

FreeBSD ports 15.1		  March 9, 2023 	     CAP_IOCTLS_LIMIT(2)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=cap_ioctls_limit&sektion=2&manpath=FreeBSD+15.1-RELEASE+and+Ports>

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