contrib/fuzz/Makefile

fuzz: new fuzzer for cext/manifest.c

This is a bit messy, because lazymanifest is tightly coupled to the
cpython API for performance reasons. As a result, we have to build a
whole Python without pymalloc (so ASAN can help us out) and link
against that. Then we have to use an embedded Python interpreter. We
could manually drive the lazymanifest in C from that point, but
experimentally just using PyEval_EvalCode isn't really any slower so
we may as well do that and write the innermost guts of the fuzzer in
Python.

Leak detection is currently disabled for this fuzzer because there are
a few global-lifetime things in our extensions that we more or less
intentionally leak and I didn't want to take the detour to work around
that for now.

This should not be pushed to our repo until
https://github.com/google/oss-fuzz/pull/1853 is merged, as this
depends on having the Python tarball around.

Differential Revision: https://phab.mercurial-scm.org/D4879

CC = clang
CXX = clang++

all: bdiff mpatch xdiff

fuzzutil.o: fuzzutil.cc fuzzutil.h
	$(CXX) $(CXXFLAGS) -g -O1 -fsanitize=fuzzer-no-link,address \
	  -std=c++17 \
	  -I../../mercurial -c -o fuzzutil.o fuzzutil.cc

fuzzutil-oss-fuzz.o: fuzzutil.cc fuzzutil.h
	$(CXX) $(CXXFLAGS) -std=c++17 \
	  -I../../mercurial -c -o fuzzutil-oss-fuzz.o fuzzutil.cc

bdiff.o: ../../mercurial/bdiff.c
	$(CC) $(CFLAGS) -fsanitize=fuzzer-no-link,address -c -o bdiff.o \
	  ../../mercurial/bdiff.c

bdiff: bdiff.cc bdiff.o fuzzutil.o
	$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
	  -std=c++17 \
	  -I../../mercurial bdiff.cc bdiff.o fuzzutil.o -o bdiff

bdiff-oss-fuzz.o: ../../mercurial/bdiff.c
	$(CC) $(CFLAGS) -c -o bdiff-oss-fuzz.o ../../mercurial/bdiff.c

bdiff_fuzzer: bdiff.cc bdiff-oss-fuzz.o fuzzutil-oss-fuzz.o
	$(CXX) $(CXXFLAGS) -std=c++17 -I../../mercurial bdiff.cc \
	  bdiff-oss-fuzz.o fuzzutil-oss-fuzz.o -lFuzzingEngine -o \
	  $$OUT/bdiff_fuzzer

mpatch.o: ../../mercurial/mpatch.c
	$(CC) -g -O1 -fsanitize=fuzzer-no-link,address -c -o mpatch.o \
	  ../../mercurial/mpatch.c

mpatch: CXXFLAGS += -std=c++17
mpatch: mpatch.cc mpatch.o fuzzutil.o
	$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
	  -I../../mercurial mpatch.cc mpatch.o fuzzutil.o -o mpatch

mpatch-oss-fuzz.o: ../../mercurial/mpatch.c
	$(CC) $(CFLAGS) -c -o mpatch-oss-fuzz.o ../../mercurial/mpatch.c

mpatch_fuzzer: mpatch.cc mpatch-oss-fuzz.o fuzzutil-oss-fuzz.o
	$(CXX) $(CXXFLAGS) -std=c++17 -I../../mercurial mpatch.cc \
	  mpatch-oss-fuzz.o fuzzutil-oss-fuzz.o -lFuzzingEngine -o \
	  $$OUT/mpatch_fuzzer

mpatch_corpus.zip:
	python mpatch_corpus.py $$OUT/mpatch_fuzzer_seed_corpus.zip

x%.o: ../../mercurial/thirdparty/xdiff/x%.c ../../mercurial/thirdparty/xdiff/*.h
	$(CC) -g -O1 -fsanitize=fuzzer-no-link,address -c \
	  -o $@ \
	  $<

xdiff: CXXFLAGS += -std=c++17
xdiff: xdiff.cc xdiffi.o xprepare.o xutils.o fuzzutil.o
	$(CXX) $(CXXFLAGS) -DHG_FUZZER_INCLUDE_MAIN=1 -g -O1 -fsanitize=fuzzer-no-link,address \
	  -I../../mercurial xdiff.cc \
	  xdiffi.o xprepare.o xutils.o fuzzutil.o -o xdiff

fuzz-x%.o: ../../mercurial/thirdparty/xdiff/x%.c ../../mercurial/thirdparty/xdiff/*.h
	$(CC) $(CFLAGS) -c \
	  -o $@ \
	  $<

xdiff_fuzzer: xdiff.cc fuzz-xdiffi.o fuzz-xprepare.o fuzz-xutils.o fuzzutil-oss-fuzz.o
	$(CXX) $(CXXFLAGS) -std=c++17 -I../../mercurial xdiff.cc \
	  fuzz-xdiffi.o fuzz-xprepare.o fuzz-xutils.o fuzzutil-oss-fuzz.o \
	  -lFuzzingEngine -o $$OUT/xdiff_fuzzer

# TODO use the $OUT env var instead of hardcoding /out
/out/sanpy/bin/python:
	cd /Python-2.7.15/ && ./configure --without-pymalloc --prefix=$$OUT/sanpy CFLAGS='-O1 -fno-omit-frame-pointer -g -fwrapv -fstack-protector-strong' LDFLAGS=-lasan  && ASAN_OPTIONS=detect_leaks=0 make && make install

sanpy: /out/sanpy/bin/python

manifest.o: sanpy ../../mercurial/cext/manifest.c
	$(CC) $(CFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -I../../mercurial \
	  -c -o manifest.o ../../mercurial/cext/manifest.c

charencode.o: sanpy ../../mercurial/cext/charencode.c
	$(CC) $(CFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -I../../mercurial \
	  -c -o charencode.o ../../mercurial/cext/charencode.c

parsers.o: sanpy ../../mercurial/cext/parsers.c
	$(CC) $(CFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -I../../mercurial \
	  -c -o parsers.o ../../mercurial/cext/parsers.c

dirs.o: sanpy ../../mercurial/cext/dirs.c
	$(CC) $(CFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -I../../mercurial \
	  -c -o dirs.o ../../mercurial/cext/dirs.c

pathencode.o: sanpy ../../mercurial/cext/pathencode.c
	$(CC) $(CFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -I../../mercurial \
	  -c -o pathencode.o ../../mercurial/cext/pathencode.c

revlog.o: sanpy ../../mercurial/cext/revlog.c
	$(CC) $(CFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -I../../mercurial \
	  -c -o revlog.o ../../mercurial/cext/revlog.c

manifest_fuzzer: sanpy manifest.cc manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o
	$(CXX) $(CXXFLAGS) `$$OUT/sanpy/bin/python-config --cflags` \
	  -Wno-register -Wno-macro-redefined \
	  -I../../mercurial manifest.cc \
	  manifest.o charencode.o parsers.o dirs.o pathencode.o revlog.o \
	  -lFuzzingEngine `$$OUT/sanpy/bin/python-config --ldflags` \
	  -o $$OUT/manifest_fuzzer

manifest_corpus.zip:
	python manifest_corpus.py $$OUT/manifest_fuzzer_seed_corpus.zip

copy_options:
	cp *.options $$OUT

clean:
	$(RM) *.o *_fuzzer \
	  bdiff \
	  mpatch \
	  xdiff

oss-fuzz: bdiff_fuzzer mpatch_fuzzer mpatch_corpus.zip xdiff_fuzzer manifest_fuzzer manifest_corpus.zip copy_options

.PHONY: all clean oss-fuzz sanpy copy_options