Re: [PATCH 5/5] man-pages: cap_rights_get: retrieve Capsicum fd rights

From: Andy Lutomirski
Date: Tue Jul 01 2014 - 10:18:55 EST


On Tue, Jul 1, 2014 at 2:19 AM, David Drysdale <drysdale@xxxxxxxxxx> wrote:
> On Mon, Jun 30, 2014 at 03:28:14PM -0700, Andy Lutomirski wrote:
>> On Mon, Jun 30, 2014 at 3:28 AM, David Drysdale <drysdale@xxxxxxxxxx> wrote:
>> > Signed-off-by: David Drysdale <drysdale@xxxxxxxxxx>
>> > ---
>> > man2/cap_rights_get.2 | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> > 1 file changed, 126 insertions(+)
>> > create mode 100644 man2/cap_rights_get.2
>> >
>> > diff --git a/man2/cap_rights_get.2 b/man2/cap_rights_get.2
>> > new file mode 100644
>> > index 000000000000..966c0ed7e336
>> > --- /dev/null
>> > +++ b/man2/cap_rights_get.2
>> > @@ -0,0 +1,126 @@
>> > +.\"
>> > +.\" Copyright (c) 2008-2010 Robert N. M. Watson
>> > +.\" Copyright (c) 2012-2013 The FreeBSD Foundation
>> > +.\" Copyright (c) 2013-2014 Google, Inc.
>> > +.\" All rights reserved.
>> > +.\"
>> > +.\" %%%LICENSE_START(BSD_2_CLAUSE)
>> > +.\" Redistribution and use in source and binary forms, with or without
>> > +.\" modification, are permitted provided that the following conditions
>> > +.\" are met:
>> > +.\" 1. Redistributions of source code must retain the above copyright
>> > +.\" notice, this list of conditions and the following disclaimer.
>> > +.\" 2. Redistributions in binary form must reproduce the above copyright
>> > +.\" notice, this list of conditions and the following disclaimer in the
>> > +.\" documentation and/or other materials provided with the distribution.
>> > +.\"
>> > +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
>> > +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>> > +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
>> > +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
>> > +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
>> > +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
>> > +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
>> > +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
>> > +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
>> > +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
>> > +.\" SUCH DAMAGE.
>> > +.\" %%%LICENSE_END
>> > +.\"
>> > +.TH CAP_RIGHTS_GET 2 2014-05-07 "Linux" "Linux Programmer's Manual"
>> > +.SH NAME
>> > +cap_rights_get \- retrieve Capsicum capability rights
>> > +.SH SYNOPSIS
>> > +.nf
>> > +.B #include <sys/capsicum.h>
>> > +.sp
>> > +.BI "int cap_rights_get(int " fd ", struct cap_rights *" rights ,
>> > +.BI " unsigned int *" fcntls ,
>> > +.BI " int *" nioctls ", unsigned int *" ioctls );
>> > +.SH DESCRIPTION
>> > +Obtain the current Capsicum capability rights for a file descriptor.
>> > +.PP
>> > +The function will fill the
>> > +.I rights
>> > +argument (if non-NULL) with the primary capability rights of the
>> > +.I fd
>> > +descriptor. The result can be examined with the
>> > +.BR cap_rights_is_set (3)
>> > +family of functions. The complete list of primary rights can be found in the
>> > +.BR rights (7)
>> > +manual page.
>> > +.PP
>> > +If the
>> > +.I fcntls
>> > +argument is non-NULL, it will be filled in with a bitmask of allowed
>> > +.BR fcntl (2)
>> > +commands; see
>> > +.BR cap_rights_limit (2)
>> > +for values. If the file descriptor does not have the
>> > +.B CAP_FCNTL
>> > +primary right, the returned
>> > +.I fcntls
>> > +value will be zero.
>> > +.PP
>> > +If the
>> > +.I nioctls
>> > +argument is non-NULL, it will be filled in with the number of allowed
>> > +.BR ioctl (2)
>> > +commands, or with the value CAP_IOCTLS_ALL to indicate that all
>> > +.BR ioctl (2)
>> > +commands are allowed. If the file descriptor does not have the
>> > +.B CAP_IOCTL
>> > +primary right, the returned
>> > +.I nioctls
>> > +value will be zero.
>> > +.PP
>> > +The
>> > +.I ioctls
>> > +argument (if non-NULL) should point at memory that can hold up to
>> > +.I nioctls
>> > +values.
>> > +The system call populates the provided buffer with up to
>> > +.I nioctls
>> > +elements, but always returns the total number of
>>
>> I assume you mean "up to the initial value of *nioctls elements" or
>> something. Can you clarify?
>>
>> --Andy
>
> Yeah, that's what I meant. Is this clearer?
>
> If the ioctls argument is non-NULL, the caller should specify
> the size of the provided buffer as the initial value of the
> nioctls argument (as a count of the number of ioctl(2) command
> values the buffer can hold). On successful completion of the
> system call, the ioctls buffer is filled with the ioctl(2) comâ
> mand values, up to maximum of the initial value of nioctls.
>

Yes. Thanks.

--Andy

--
Andy Lutomirski
AMA Capital Management, LLC
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