Start work on fancy compiler tricks to expose extra stuff to our tests

This is mainly a matter of automake trickery: we build each static
library in two versions now: one with the TOR_UNIT_TESTS macro
defined, and one without.  When TOR_UNIT_TESTS is defined, we can
enable mocking and expose more functions. When it's not defined, we
can lock the binary down more.

The alternatives would be to have alternate build modes: a "testing
configuration" for building the libraries with test support, and a
"production configuration" for building them without.  I don't favor
that approach, since I think it would mean more people runnning
binaries build for testing, or more people not running unit tests.

.gitignore

@@ -128,10 +128,13 @@
 /src/common/Makefile.in
 /src/common/common_sha1.i
 /src/common/libor.a
+/src/common/libor-testing.a
 /src/common/libor.lib
 /src/common/libor-crypto.a
+/src/common/libor-crypto-testing.a
 /src/common/libor-crypto.lib
 /src/common/libor-event.a
+/src/common/libor-event-testing.a
 /src/common/libor-event.lib
 /src/common/libcurve25519_donna.a
 /src/common/libcurve25519_donna.lib
@@ -150,6 +153,7 @@
 /src/or/tor
 /src/or/tor.exe
 /src/or/libtor.a
+/src/or/libtor-testing.a
 /src/or/libtor.lib
 
 # /src/test

changes/fancy_testing

@@ -0,0 +1,9 @@
+  o Build features:
+
+    - Tor now builds each source file in two modes: a mode that avoids
+      exposing identifiers needlessly, and another mode that exposes
+      more identifiers for testing. This lets the compiler do better at
+      optimizing the production code, while enabling us to take more
+      radical measures to let the unit tests test things.
+
+

configure.ac

@@ -39,6 +39,10 @@ AC_ARG_ENABLE(static-tor,
    AS_HELP_STRING(--enable-static-tor, Create an entirely static Tor binary. Requires --with-openssl-dir and --with-libevent-dir and --with-zlib-dir))
 AC_ARG_ENABLE(curve25519,
    AS_HELP_STRING(--disable-curve25519, Build Tor with no curve25519 elliptic-curve crypto support))
+AC_ARG_ENABLE(unittests,
+   AS_HELP_STRING(--disable-unittests, [Don't build unit tests for Tor. Risky!]))
+
+AM_CONDITIONAL(UNITTESTS_ENABLED, test x$unittests != xno)
 
 if test "$enable_static_tor" = "yes"; then
   enable_static_libevent="yes";

src/common/include.am

@@ -1,5 +1,15 @@
 
-noinst_LIBRARIES+= src/common/libor.a src/common/libor-crypto.a src/common/libor-event.a
+noinst_LIBRARIES += \
+	src/common/libor.a \
+	src/common/libor-crypto.a \
+	src/common/libor-event.a
+
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += \
+	src/common/libor-testing.a \
+	src/common/libor-crypto-testing.a \
+	src/common/libor-event-testing.a
+endif
 
 EXTRA_DIST+= \
   src/common/common_sha1.i	\
@@ -38,7 +48,7 @@ if CURVE25519_ENABLED
 libcrypto_extra_source=src/common/crypto_curve25519.c
 endif
 
-src_common_libor_a_SOURCES = \
+LIBOR_A_SOURCES = \
   src/common/address.c					\
   src/common/compat.c					\
   src/common/container.c				\
@@ -51,7 +61,7 @@ src_common_libor_a_SOURCES = \
   src/common/util_codedigest.c				\
   $(libor_extra_source)
 
-src_common_libor_crypto_a_SOURCES = \
+LIBOR_CRYPTO_A_SOURCES = \
   src/common/aes.c		\
   src/common/crypto.c		\
   src/common/crypto_format.c	\
@@ -59,7 +69,19 @@ src_common_libor_crypto_a_SOURCES = \
   src/common/tortls.c		\
   $(libcrypto_extra_source)
 
-src_common_libor_event_a_SOURCES = src/common/compat_libevent.c
+LIBOR_EVENT_A_SOURCES = src/common/compat_libevent.c
+
+src_common_libor_a_SOURCES = $(LIBOR_A_SOURCES)
+src_common_libor_crypto_a_SOURCES = $(LIBOR_CRYPTO_A_SOURCES)
+src_common_libor_event_a_SOURCES = $(LIBOR_EVENT_A_SOURCES)
+
+src_common_libor_testing_a_SOURCES = $(LIBOR_A_SOURCES)
+src_common_libor_crypto_testing_a_SOURCES = $(LIBOR_CRYPTO_A_SOURCES)
+src_common_libor_event_testing_a_SOURCES = $(LIBOR_EVENT_A_SOURCES)
+
+src_common_libor_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
+src_common_libor_crypto_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
+src_common_libor_event_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
 
 COMMONHEADERS = \
   src/common/address.h				\
@@ -74,6 +96,7 @@ COMMONHEADERS = \
   src/common/memarea.h				\
   src/common/mempool.h				\
   src/common/procmon.h				\
+  src/common/testsupport.h			\
   src/common/torgzip.h				\
   src/common/torint.h				\
   src/common/torlog.h				\

src/common/testsupport.h

@@ -0,0 +1,14 @@
+/* Copyright (c) 2013, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_TESTSUPPORT_H
+#define TOR_TESTSUPPORT_H
+
+#ifdef TOR_UNIT_TESTS
+#define STATIC_UNLESS_TESTING
+#else
+#define STATIC_UNLESS_TESTING static
+#endif
+
+#endif
+

src/or/include.am

@@ -1,5 +1,10 @@
 bin_PROGRAMS+= src/or/tor
-noinst_LIBRARIES+= src/or/libtor.a
+noinst_LIBRARIES += \
+	src/or/libtor.a
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += \
+	src/or/libtor-testing.a
+endif
 
 if BUILD_NT_SERVICES
 tor_platform_source=src/or/ntmain.c
@@ -21,7 +26,7 @@ else
 onion_ntor_source=
 endif
 
-src_or_libtor_a_SOURCES = \
+LIBTOR_A_SOURCES = \
 	src/or/addressmap.c				\
 	src/or/buffers.c				\
 	src/or/channel.c				\
@@ -77,6 +82,9 @@ src_or_libtor_a_SOURCES = \
 	$(onion_ntor_source)				\
 	src/or/config_codedigest.c
 
+src_or_libtor_a_SOURCES = $(LIBTOR_A_SOURCES)
+src_or_libtor_testing_a_SOURCES = $(LIBTOR_A_SOURCES)
+
 #libtor_a_LIBADD = ../common/libor.a ../common/libor-crypto.a \
 #	../common/libor-event.a
 
@@ -90,6 +98,8 @@ AM_CPPFLAGS += -DSHARE_DATADIR="\"$(datadir)\"" \
         -DLOCALSTATEDIR="\"$(localstatedir)\"" \
         -DBINDIR="\"$(bindir)\""
 
+src_or_libtor_testing_a_CPPFLAGS = -DTOR_UNIT_TESTS $(AM_CPPFLAGS)
+
 # -L flags need to go in LDFLAGS. -l flags need to go in LDADD.
 # This seems to matter nowhere but on windows, but I assure you that it
 # matters a lot there, and is quite hard to debug if you forget to do it.

src/test/include.am

@@ -1,11 +1,15 @@
 TESTS+= src/test/test
 
-noinst_PROGRAMS+= src/test/test src/test/test-child src/test/bench
+noinst_PROGRAMS+= src/test/bench
+if UNITTESTS_ENABLED
+noinst_PROGRAMS+= src/test/test src/test/test-child
+endif
 
 src_test_AM_CPPFLAGS = -DSHARE_DATADIR="\"$(datadir)\"" \
         -DLOCALSTATEDIR="\"$(localstatedir)\"" \
         -DBINDIR="\"$(bindir)\""	       \
-	-I"$(top_srcdir)/src/or" -I"$(top_srcdir)/src/ext"
+	-I"$(top_srcdir)/src/or" -I"$(top_srcdir)/src/ext" \
+	-DTOR_UNIT_TESTS
 
 # -L flags need to go in LDFLAGS. -l flags need to go in LDADD.
 # This seems to matter nowhere but on Windows, but I assure you that it
@@ -36,9 +40,9 @@ src_test_bench_CPPFLAGS= $(src_test_AM_CPPFLAGS)
 
 src_test_test_LDFLAGS = @TOR_LDFLAGS_zlib@ @TOR_LDFLAGS_openssl@ \
         @TOR_LDFLAGS_libevent@
-src_test_test_LDADD = src/or/libtor.a src/common/libor.a \
-	src/common/libor-crypto.a $(LIBDONNA) \
-	src/common/libor-event.a \
+src_test_test_LDADD = src/or/libtor-testing.a src/common/libor-testing.a \
+	src/common/libor-crypto-testing.a $(LIBDONNA) \
+	src/common/libor-event-testing.a \
 	@TOR_ZLIB_LIBS@ @TOR_LIB_MATH@ @TOR_LIBEVENT_LIBS@ \
 	@TOR_OPENSSL_LIBS@ @TOR_LIB_WS32@ @TOR_LIB_GDI@ @CURVE25519_LIBS@