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cap_ioctls_limit(2) [freebsd man page]

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

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 <> under sponsorship of the FreeBSD Foundation. BSD
March 27, 2014 BSD

Check Out this Related Man Page

IOCTL(2)						     Linux Programmer's Manual							  IOCTL(2)

ioctl - control device SYNOPSIS
#include <sys/ioctl.h> int ioctl(int d, int request, ...); DESCRIPTION
The ioctl function manipulates the underlying device parameters of special files. In particular, many operating characteristics of charac- ter special files (e.g. terminals) may be controlled with ioctl requests. The argument d must be an open file descriptor. The second argument is a device-dependent request code. The third argument is an untyped pointer to memory. It's traditionally char *argp (from the days before void * was valid C), and will be so named for this discussion. An ioctl request has encoded in it whether the argument is an in parameter or out parameter, and the size of the argument argp in bytes. Macros and defines used in specifying an ioctl request are located in the file <sys/ioctl.h>. RETURN VALUE
Usually, on success zero is returned. A few ioctls use the return value as an output parameter and return a nonnegative value on success. On error, -1 is returned, and errno is set appropriately. ERRORS
EBADF d is not a valid descriptor. EFAULT argp references an inaccessible memory area. ENOTTY d is not associated with a character special device. ENOTTY The specified request does not apply to the kind of object that the descriptor d references. EINVAL Request or argp is not valid. CONFORMING TO
No single standard. Arguments, returns, and semantics of ioctl(2) vary according to the device driver in question (the call is used as a catch-all for operations that don't cleanly fit the Unix stream I/O model). See ioctl_list(2) for a list of many of the known ioctl calls. The ioctl function call appeared in Version 7 AT&T Unix. SEE ALSO
execve(2), fcntl(2), ioctl_list(2), mt(4), sd(4), tty(4) BSD Man Page 2000-09-21 IOCTL(2)
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