Index: head/lib/libcasper/libcasper/libcasper.3
===================================================================
--- head/lib/libcasper/libcasper/libcasper.3	(revision 327538)
+++ head/lib/libcasper/libcasper/libcasper.3	(revision 327539)
@@ -1,318 +1,319 @@
 .\" Copyright (c) 2013 The FreeBSD Foundation
 .\" All rights reserved.
 .\"
 .\" This documentation was written by Pawel Jakub Dawidek under sponsorship
 .\" from the FreeBSD Foundation.
 .\"
 .\" 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 AUTHORS 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 AUTHORS 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.
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 2, 2018
+.Dd January 3, 2018
 .Dt LIBCASPER 3
 .Os
 .Sh NAME
 .Nm cap_init ,
 .Nm cap_wrap ,
 .Nm cap_unwrap ,
 .Nm cap_sock ,
 .Nm cap_clone ,
 .Nm cap_close ,
 .Nm cap_limit_get ,
 .Nm cap_limit_set ,
 .Nm cap_send_nvlist ,
 .Nm cap_recv_nvlist ,
 .Nm cap_xfer_nvlist ,
 .Nm cap_service_open
 .Nd "library for handling application capabilities"
 .Sh LIBRARY
 .Lb libcasper
 .Sh SYNOPSIS
 .In sys/nv.h
 .In libcasper.h
 .Ft "cap_channel_t *"
 .Fn cap_init "void"
 .Ft "cap_channel_t *"
 .Fn cap_wrap "int sock"
 .Ft "int"
 .Fn cap_unwrap "cap_channel_t *chan"
 .Ft "int"
 .Fn cap_sock "const cap_channel_t *chan"
 .Ft "cap_channel_t *"
 .Fn cap_clone "const cap_channel_t *chan"
 .Ft "void"
 .Fn cap_close "cap_channel_t *chan"
 .Ft "int"
 .Fn cap_limit_get "const cap_channel_t *chan" "nvlist_t **limitsp"
 .Ft "int"
 .Fn cap_limit_set "const cap_channel_t *chan" "nvlist_t *limits"
 .Ft "int"
 .Fn cap_send_nvlist "const cap_channel_t *chan" "const nvlist_t *nvl"
 .Ft "nvlist_t *"
 .Fn cap_recv_nvlist "const cap_channel_t *chan" "int flags"
 .Ft "nvlist_t *"
 .Fn cap_xfer_nvlist "const cap_channel_t *chan" "nvlist_t *nvl" "int flags"
 .Ft "cap_channel_t *"
 .Fn cap_service_open "const cap_channel_t *chan" "const char *name"
 .Sh DESCRIPTION
 The
 .Nm libcasper
 library allows to manage application capabilities through the casper process.
 .Pp
 The application capability (represented by the
 .Vt cap_channel_t
 type) is a communication channel between the caller and the casper process
 daemon or an instance of one of its services.
 A capability to the casper process obtained with the
 .Fn cap_init
 function allows to create capabilities to casper's services via the
 .Fn cap_service_open
 function.
 .Pp
 The
 .Fn cap_init
 function opens capability to the casper process.
 .Pp
 The
 .Fn cap_wrap
 function creates
 .Vt cap_channel_t
 based on the given socket.
 The function is used when capability is inherited through
 .Xr execve 2
 or send over
 .Xr unix 4
 domain socket as a regular file descriptor and has to be represented as
 .Vt cap_channel_t
 again.
 .Pp
 The
 .Fn cap_unwrap
 function is the opposite of the
 .Fn cap_wrap
 function.
 It frees the
 .Vt cap_channel_t
 structure and returns
 .Xr unix 4
 domain socket associated with it.
 .Pp
 The
 .Fn cap_clone
 function clones the given capability.
 .Pp
 The
 .Fn cap_close
 function closes the given capability.
 .Pp
 The
 .Fn cap_sock
 function returns
 .Xr unix 4
 domain socket descriptor associated with the given capability for use with
 system calls like
 .Xr kevent 2 ,
 .Xr poll 2
 and
 .Xr select 2 .
 .Pp
 The
 .Fn cap_limit_get
 function stores current limits of the given capability in the
 .Fa limitsp
 argument.
 If the function return
 .Va 0
 and
 .Dv NULL
 is stored in
 .Fa limitsp
 it means there are no limits set.
 .Pp
 The
 .Fn cap_limit_set
 function sets limits for the given capability.
 The limits are provided as nvlist.
 The exact format depends on the service the capability represents.
 .Pp
 The
 .Fn cap_send_nvlist
 function sends the given nvlist over the given capability.
 This is low level interface to communicate with casper services.
 Most services should provide higher level API.
 .Pp
 The
 .Fn cap_recv_nvlist
 function receives the given nvlist over the given capability.
 The
 .Fa flags
 argument defines what type the top nvlist is expected to be.
 If the nvlist flags do not match the flags passed to
 .Fn cap_recv_nvlist ,
 the nvlist will not be returned.
 .Pp
 The
 .Fn cap_xfer_nvlist
 function sends the given nvlist, destroys it and receives new nvlist in
 response over the given capability.
 The
 .Fa flags
 argument defines what type the top nvlist is expected to be.
 If the nvlist flags do not match the flags passed to
 .Fn cap_xfer_nvlist ,
 the nvlist will not be returned.
 It does not matter if the function succeeds or fails, the nvlist given
 for sending will always be destroyed once the function returns.
 .Pp
 The
 .Fn cap_service_open
 function opens casper service of the given name through casper capability
 obtained via the
 .Fn cap_init
 function.
 The function returns capability that provides access to opened service.
 Casper supports the following services in the base system:
 .Bl -tag -width "system.random" -compact -offset indent
 .Pp
 .It system.dns
 provides DNS libc compatible API
 .It system.grp
 provides
 .Xr getgrent 3
 compatible API
 .It system.pwd
 provides
 .Xr getpwent 3
 compatible API
 .It system.random
-allows to obtain entropy from /dev/random
+allows to obtain entropy from
+.Pa /dev/random
 .It system.sysctl
 provides
 .Xr sysctlbyname 3
 compatible API
 .It system.syslog
 provides
 .Xr syslog 3
 compatible API
 .Sh RETURN VALUES
 The
 .Fn cap_clone ,
 .Fn cap_init ,
 .Fn cap_recv_nvlist ,
 .Fn cap_service_open ,
 .Fn cap_wrap
 and
 .Fn cap_xfer_nvlist
 functions return
 .Dv NULL
 and set the
 .Va errno
 variable on failure.
 .Pp
 The
 .Fn cap_limit_get ,
 .Fn cap_limit_set
 and
 .Fn cap_send_nvlist
 functions return
 .Dv -1
 and set the
 .Va errno
 variable on failure.
 .Pp
 The
 .Fn cap_close ,
 .Fn cap_sock
 and
 .Fn cap_unwrap
 functions always succeed.
 .Sh EXAMPLES
 The following example first opens capability to the casper then using this
 capability creates new capability to the
 .Nm system.dns
 casper service and uses the latter capability to resolve IP address.
 .Bd -literal
 cap_channel_t *capcas, *capdns;
 nvlist_t *limits;
 const char *ipstr = "127.0.0.1";
 struct in_addr ip;
 struct hostent *hp;
 
 /* Open capability to the Casper. */
 capcas = cap_init();
 if (capcas == NULL)
 	err(1, "Unable to contact Casper");
 
 /* Enter capability mode sandbox. */
 if (cap_enter() < 0 && errno != ENOSYS)
 	err(1, "Unable to enter capability mode");
 
 /* Use Casper capability to create capability to the system.dns service. */
 capdns = cap_service_open(capcas, "system.dns");
 if (capdns == NULL)
 	err(1, "Unable to open system.dns service");
 
 /* Close Casper capability, we don't need it anymore. */
 cap_close(capcas);
 
 /* Limit system.dns to reverse DNS lookups and IPv4 addresses. */
 limits = nvlist_create(0);
 nvlist_add_string(limits, "type", "ADDR");
 nvlist_add_number(limits, "family", (uint64_t)AF_INET);
 if (cap_limit_set(capdns, limits) < 0)
 	err(1, "Unable to limit access to the system.dns service");
 
 /* Convert IP address in C-string to in_addr. */
 if (!inet_aton(ipstr, &ip))
 	errx(1, "Unable to parse IP address %s.", ipstr);
 
 /* Find hostname for the given IP address. */
 hp = cap_gethostbyaddr(capdns, (const void *)&ip, sizeof(ip), AF_INET);
 if (hp == NULL)
 	errx(1, "No name associated with %s.", ipstr);
 
 printf("Name associated with %s is %s.\\n", ipstr, hp->h_name);
 .Ed
 .Sh SEE ALSO
 .Xr cap_enter 2 ,
 .Xr execve 2 ,
 .Xr kevent 2 ,
 .Xr poll 2 ,
 .Xr select 2 ,
 .Xr cap_gethostbyaddr 3 ,
 .Xr err 3 ,
 .Xr gethostbyaddr 3 ,
 .Xr inet_aton 3 ,
 .Xr nv 3 ,
 .Xr capsicum 4 ,
 .Xr unix 4
 .Sh AUTHORS
 The
 .Nm libcasper
 library was implemented by
 .An Pawel Jakub Dawidek Aq Mt pawel@dawidek.net
 under sponsorship from the FreeBSD Foundation.
 The
 .Nm libcasper
 new architecture was implemented by
 .An Mariusz Zaborski Aq Mt oshogbo@FreeBSD.org
 .