cap_fcntls_limit2

Usage

Library

Standard C Library (libc, -lc)

Overview

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

The cap_fcntls_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.

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.