Introduce caspermocks.

The idea behinds mocks is that we don't need to ifdef a lot of code in
tools itself but those defines are hidden in the casper library.
Right now the mocks are implemented as define/inlines functions.
There was a very long discussion how this should be implemented.
This approach has some advantages like we don't need to link to any additional
libraries. Unfortunately there are also some disadvantages for example it is
easy to get library out of sync between two versions of functions or that we
need extra define to compile program with casper support.
This isn't an ideal solution but it's good enough for now and should simplify
capsicumizing programs. This also doesn't close us any other ways to do those
mocks and this should evolve in time.

Discussed with:	pjd, emaste, ed, rwatson, bapt, cem, bdrewery
Differential Revision:    https://reviews.freebsd.org/D8753

lib/Makefile

@@ -35,6 +35,7 @@ SUBDIR=	${SUBDIR_BOOTSTRAP} \
 	libcalendar \
 	libcam \
 	libcapsicum \
+	libcasper \
 	libcompat \
 	libcrypt \
 	libdevctl \
@@ -127,7 +128,6 @@ SUBDIR.${MK_ATM}+=	libngatm
 SUBDIR.${MK_BLACKLIST}+=libblacklist
 SUBDIR.${MK_BLUETOOTH}+=libbluetooth libsdp
 SUBDIR.${MK_BSNMP}+=	libbsnmp
-SUBDIR.${MK_CASPER}+=	libcasper
 
 .if !defined(COMPAT_32BIT) && !defined(COMPAT_SOFTFP)
 SUBDIR.${MK_CLANG}+=	clang

lib/libcasper/Makefile.inc

@@ -1,3 +1,9 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
+.if ${MK_CASPER} != "no"
+CFLAGS+=-DWITH_CASPER
+.endif
+
 .include "../Makefile.inc"

lib/libcasper/libcasper/Makefile

@@ -1,16 +1,21 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 PACKAGE=${LIB}
-LIB=	casper
 
 SHLIB_MAJOR=	0
 SHLIBDIR?=	/lib
 
+.if ${MK_CASPER} != "no"
+LIB=	casper
+
 SRCS=	libcasper.c
 SRCS+=	libcasper_impl.c
 SRCS+=	libcasper_service.c
 SRCS+=	service.c
 SRCS+=	zygote.c
+.endif
 
 INCS=	libcasper.h
 INCS+=	libcasper_service.h

lib/libcasper/libcasper/libcasper.h

@@ -1,6 +1,6 @@
 /*-
  * Copyright (c) 2012-2013 The FreeBSD Foundation
- * Copyright (c) 2015 Mariusz Zaborski <[email protected]>
+ * Copyright (c) 2015-2017 Mariusz Zaborski <[email protected]>
  * All rights reserved.
  *
  * This software was developed by Pawel Jakub Dawidek under sponsorship from
@@ -33,7 +33,15 @@
 #ifndef	_LIBCASPER_H_
 #define	_LIBCASPER_H_
 
+#ifdef HAVE_CASPER
+#define WITH_CASPER
+#endif
+
 #include <sys/types.h>
+#include <sys/nv.h>
+
+#include <stdlib.h>
+#include <unistd.h>
 
 #ifndef	_NVLIST_T_DECLARED
 #define	_NVLIST_T_DECLARED
@@ -44,72 +52,191 @@ typedef struct nvlist nvlist_t;
 
 #ifndef	_CAP_CHANNEL_T_DECLARED
 #define	_CAP_CHANNEL_T_DECLARED
+#ifdef WITH_CASPER
 struct cap_channel;
 
 typedef struct cap_channel cap_channel_t;
-#endif
+#else
+struct cap_channel {
+	int cch_fd;
+};
+typedef struct cap_channel cap_channel_t;
+#endif /* ! WITH_CASPER */
+#endif /* ! _CAP_CHANNEL_T_DECLARED */
 
 /*
  * The functions opens unrestricted communication channel to Casper.
  */
+#ifdef WITH_CASPER
 cap_channel_t *cap_init(void);
+#else
+static inline cap_channel_t *
+cap_init(void)
+{
+	cap_channel_t *chan;
+
+	chan = malloc(sizeof(*chan));
+	if (chan != NULL) {
+		chan->cch_fd = -1;
+	}
+	return (chan);
+}
+#endif
 
 /*
  * The functions to communicate with service.
  */
+#ifdef WITH_CASPER
 cap_channel_t	*cap_service_open(const cap_channel_t *chan, const char *name);
 int		 cap_service_limit(const cap_channel_t *chan,
 		    const char * const *names, size_t nnames);
+#else
+#define	cap_service_open(chan, name)		(cap_init())
+#define	cap_service_limit(chan, names, nnames)	(0)
+#endif
 
 /*
  * The function creates cap_channel_t based on the given socket.
  */
+#ifdef WITH_CASPER
 cap_channel_t *cap_wrap(int sock);
+#else
+static inline cap_channel_t *
+cap_wrap(int sock)
+{
+	cap_channel_t *chan;
+
+	chan = cap_init();
+	if (chan != NULL) {
+		chan->cch_fd = sock;
+	}
+	return (chan);
+}
+#endif
 
 /*
  * The function returns communication socket and frees cap_channel_t.
  */
+#ifdef WITH_CASPER
 int	cap_unwrap(cap_channel_t *chan);
+#else
+#define	cap_unwrap(chan)	(chan->cch_fd)
+#endif
 
 /*
  * The function clones the given capability.
  */
+#ifdef WITH_CASPER
 cap_channel_t *cap_clone(const cap_channel_t *chan);
+#else
+static inline cap_channel_t *
+cap_clone(const cap_channel_t *chan)
+{
+	cap_channel_t *newchan;
+
+	newchan = cap_init();
+	if (newchan == NULL) {
+		return (NULL);
+	}
+
+	if (chan->cch_fd == -1) {
+		newchan->cch_fd = -1;
+	} else {
+		newchan->cch_fd = dup(chan->cch_fd);
+		if (newchan->cch_fd < 0) {
+			free(newchan);
+			newchan = NULL;
+		}
+	}
+
+	return (newchan);
+}
+#endif
 
 /*
  * The function closes the given capability.
  */
+#ifdef WITH_CASPER
 void	cap_close(cap_channel_t *chan);
+#else
+static inline void
+cap_close(cap_channel_t *chan)
+{
+
+	if (chan->cch_fd >= 0) {
+		close(chan->cch_fd);
+	}
+	free(chan);
+}
+#endif
 
 /*
  * The function returns socket descriptor associated with the given
  * cap_channel_t for use with select(2)/kqueue(2)/etc.
  */
+#ifdef WITH_CASPER
 int	cap_sock(const cap_channel_t *chan);
+#else
+#define	cap_sock(chan)	(chan->cch_fd)
+#endif
 
 /*
  * The function limits the given capability.
  * It always destroys 'limits' on return.
  */
+#ifdef WITH_CASPER
 int	cap_limit_set(const cap_channel_t *chan, nvlist_t *limits);
+#else
+#define	cap_limit_set(chan, limits)	(0)
+#endif
 
 /*
  * The function returns current limits of the given capability.
  */
+#ifdef WITH_CASPER
 int	cap_limit_get(const cap_channel_t *chan, nvlist_t **limitsp);
+#else
+static inline int
+cap_limit_get(const cap_channel_t *chan __unused, nvlist_t **limitsp)
+{
+
+	*limitsp = nvlist_create(0);
+	return (0);
+}
+#endif
 
 /*
  * Function sends nvlist over the given capability.
  */
+#ifdef WITH_CASPER
 int	cap_send_nvlist(const cap_channel_t *chan, const nvlist_t *nvl);
+#else
+#define	cap_send_nvlist(chan, nvl)	(0)
+#endif
+
 /*
  * Function receives nvlist over the given capability.
  */
+#ifdef WITH_CASPER
 nvlist_t *cap_recv_nvlist(const cap_channel_t *chan, int flags);
+#else
+#define	cap_recv_nvlist(chan, flags)	(0)
+#endif
+
 /*
  * Function sends the given nvlist, destroys it and receives new nvlist in
  * response over the given capability.
  */
+#ifdef WITH_CASPER
 nvlist_t *cap_xfer_nvlist(const cap_channel_t *chan, nvlist_t *nvl, int flags);
+#else
+static inline nvlist_t *
+cap_xfer_nvlist(const cap_channel_t *chan __unused, nvlist_t *nvl, int flags)
+{
+
+	nvlist_destroy(nvl);
+	return (nvlist_create(flags));
+}
+#endif
 
 #endif	/* !_LIBCASPER_H_ */

lib/libcasper/services/Makefile

@@ -1,5 +1,7 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 SUBDIR=		cap_dns
 SUBDIR+=	cap_grp
 SUBDIR+=	cap_pwd

lib/libcasper/services/cap_dns/Makefile

@@ -5,12 +5,15 @@ SHLIBDIR?=	/lib/casper
 .include <src.opts.mk>
 
 PACKAGE=libcasper
-LIB=	cap_dns
 
 SHLIB_MAJOR=	0
 INCSDIR?=	${INCLUDEDIR}/casper
 
+.if ${MK_CASPER} != "no"
+LIB=	cap_dns
+
 SRCS=	cap_dns.c
+.endif
 
 INCS=	cap_dns.h
 

lib/libcasper/services/cap_dns/cap_dns.h

@@ -32,11 +32,16 @@
 #ifndef	_CAP_DNS_H_
 #define	_CAP_DNS_H_
 
+#ifdef HAVE_CASPER
+#define WITH_CASPER
+#endif
+
 #include <sys/socket.h>	/* socklen_t */
 
 struct addrinfo;
 struct hostent;
 
+#ifdef WITH_CASPER
 struct hostent *cap_gethostbyname(cap_channel_t *chan, const char *name);
 struct hostent *cap_gethostbyname2(cap_channel_t *chan, const char *name,
     int type);
@@ -53,5 +58,18 @@ int cap_dns_type_limit(cap_channel_t *chan, const char * const *types,
     size_t ntypes);
 int cap_dns_family_limit(cap_channel_t *chan, const int *families,
     size_t nfamilies);
+#else
+#define	cap_gethostbyname(chan, name)		 gethostbyname(name)
+#define cap_gethostbyname2(chan, name, type)	 gethostbyname2(name, type)
+#define cap_gethostbyaddr(chan, addr, len, type) gethostbyaddr(addr, len, type)
+
+#define	cap_getaddrinfo(chan, hostname, servname, hints, res)			\
+	getaddrinfo(hostname, servname, hints, res)
+#define	cap_getnameinfo(chan, sa, salen, host, hostlen, serv, servlen, flags)	\
+	getnameinfo(sa, salen, host, hostlen, serv, servlen, flags)
+
+#define	cap_dns_type_limit(chan, types, ntypes)		(0)
+#define cap_dns_family_limit(chan, families, nfamilies)	(0)
+#endif
 
 #endif	/* !_CAP_DNS_H_ */

lib/libcasper/services/cap_dns/tests/Makefile

@@ -1,9 +1,13 @@
 # $FreeBSD$
 
+.include <src.opts.mk>
+
 TAP_TESTS_C=	dns_test
 
+.if ${MK_CASPER} != "no"
 LIBADD+=	casper
 LIBADD+=	cap_dns
+.endif
 LIBADD+=	nv
 
 WARNS?=		3

lib/libcasper/services/cap_dns/tests/dns_test.c

@@ -31,6 +31,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/capsicum.h>
+#include <sys/nv.h>
 
 #include <arpa/inet.h>
 #include <netinet/in.h>

lib/libcasper/services/cap_grp/Makefile

@@ -5,12 +5,15 @@ SHLIBDIR?=	/lib/casper
 .include <src.opts.mk>
 
 PACKAGE=libcasper
-LIB=	cap_grp
 
 SHLIB_MAJOR=	0
 INCSDIR?=	${INCLUDEDIR}/casper
 
+.if ${MK_CASPER} != "no"
+LIB=	cap_grp
+
 SRCS=	cap_grp.c
+.endif
 
 INCS=	cap_grp.h