[tor-commits] [stegotorus/master] Enforce no addition of new global variables.

[zwol at torproject.org]

commit 925d3f6705a52b41478282cd2bb764f3318aabc4
Author: Zack Weinberg <zackw at cmu.edu>
Date:   Wed Feb 29 16:51:03 2012 -0800

    Enforce no addition of new global variables.
---
 Makefile.am          |   14 +++++++++
 src/audit-globals.sh |   74 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 0 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index d81d072..280f32a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -80,6 +80,7 @@ noinst_HEADERS = \
 	src/test/unittest.h
 
 dist_noinst_SCRIPTS = \
+	src/audit-globals.sh \
 	src/genmodtable.sh \
 	src/test/genunitgrps.sh
 
@@ -94,11 +95,16 @@ CLEANFILES = protolist.cc steglist.cc unitgrplist.cc \
 
 GMOD  = $(SHELL) $(srcdir)/src/genmodtable.sh
 GUNIT = $(SHELL) $(srcdir)/src/test/genunitgrps.sh
+AGLOB = $(SHELL) $(srcdir)/src/audit-globals.sh
 
 AM_V_gs   = $(AM_V_gs_$(V))
 AM_V_gs_  = $(AM_V_gs_$(AM_DEFAULT_VERBOSITY))
 AM_V_gs_0 = @echo "  GEN   " $(patsubst stamp-%,%.cc,$@);
 
+AM_V_ag   = $(AM_V_ag_$(V))
+AM_V_ag_  = $(AM_V_ag_$(AM_DEFAULT_VERBOSITY))
+AM_V_ag_0 = @echo "  AGLOB ";
+
 protolist.cc: stamp-protolist ;
 stamp-protolist: $(PROTOCOLS) Makefile src/genmodtable.sh
 	$(AM_V_gs) $(GMOD) protolist.cc $(filter %.cc, $^)
@@ -114,6 +120,14 @@ stamp-unitgrplist: $(UTGROUPS) Makefile src/test/genunitgrps.sh
 	$(AM_V_gs) $(GUNIT) unitgrplist.cc $(filter %.cc, $^)
 	$(AM_V_at) touch stamp-unitgrplist
 
+stamp-audit-globals: src/audit-globals.sh Makefile \
+  $(libstegotorus_a_OBJECTS) $(stegotorus_OBJECTS)
+	$(AM_V_ag) $(AGLOB) $(libstegotorus_a_OBJECTS) $(stegotorus_OBJECTS)
+	$(AM_V_at) touch stamp-audit-globals
+
+# prevent stegotorus from being linked if s-a-g fails
+EXTRA_stegotorus_DEPENDENCIES = stamp-audit-globals
+
 # Testing
 check-local:
 	@echo --- Unit tests ---
diff --git a/src/audit-globals.sh b/src/audit-globals.sh
new file mode 100644
index 0000000..cc2387b
--- /dev/null
+++ b/src/audit-globals.sh
@@ -0,0 +1,74 @@
+#! /bin/sh
+
+# Due to the multi-listener architecture of stegotorus, nearly all
+# global variables are bugs.  This program enforces a white-list of
+# global variables (in stegotorus itself) that are known to be okay.
+# It's called from the Makefile with all of stegotorus's object files
+# on the command line.  It produces no output, and exits successfully,
+# if no new globals have appeared; otherwise it prints error messages
+# and exits unsuccessfully.
+
+status=0
+symbols=$(nm -o "$@" |
+c++filt |
+sed '
+  # Tidy up the list and remove all symbols we do not care about.
+  / [DBdb] /!d
+
+  s/^src\///
+  s/\.o: / /
+  s/\.obj: / /
+  s/ [0-9a-fA-F][0-9a-fA-F]* [DBdb] / /
+
+  # This is the whitelist, in the form of a bunch of sed "d" commands.
+  # It cares about both the names and the object files that define
+  # them.  The above commands have stripped any leading src/ and/or
+  # .o or .obj extension.
+
+  # These are genuinely OK.
+  /^connections circuits$/d
+  /^connections connections$/d
+  /^connections closing_all_connections$/d
+  /^connections last_ckt_serial$/d
+  /^connections last_conn_serial$/d
+  /^connections shutting_down$/d
+  /^main allow_kq$/d
+  /^main the_event_base$/d
+  /^main handle_signal_cb(int, short, void\*)::got_sigint$/d
+  /^network listeners$/d
+  /^rng rng$/d
+  /^util log_dest$/d
+  /^util log_min_sev$/d
+  /^util the_evdns_base$/d
+
+  # These are grandfathered; they need to be removed.
+  /^steg\/b64cookies std::__ioinit$/d
+  /^steg\/b64decode std::__ioinit$/d
+  /^steg\/b64encode std::__ioinit$/d
+  /^steg\/embed embed_init$/d
+  /^steg\/embed embed_num_traces$/d
+  /^steg\/embed embed_traces$/d
+  /^steg\/http has_peer_name$/d
+  /^steg\/http peername$/d
+  /^steg\/http std::__ioinit$/d
+  /^steg\/payloads _payload_count$/d
+  /^steg\/payloads initTypePayload$/d
+  /^steg\/payloads max_HTML_capacity$/d
+  /^steg\/payloads max_JS_capacity$/d
+  /^steg\/payloads max_PDF_capacity$/d
+  /^steg\/payloads typePayload$/d
+  /^steg\/payloads typePayloadCap$/d
+  /^steg\/payloads typePayloadCount$/d
+')
+
+if [ -n "$symbols" ]; then
+    status=1
+    echo '*** New global variables introduced:'
+    set fnord $symbols
+    shift
+    while [ $# -gt 0 ]; do
+        printf '  %s.o\t%s\n' "$1" "$2"
+        shift 2
+    done
+fi
+exit $status