@@ -159,6 +159,7 @@ tools/fuzz/libelf/afl-libelf-fuzzer
tools/fuzz/x86_instruction_emulator/asm
tools/fuzz/x86_instruction_emulator/x86_emulate*
tools/fuzz/x86_instruction_emulator/afl-harness
+tools/fuzz/x86_instruction_emulator/afl-harness-cov
tools/helpers/_paths.h
tools/helpers/init-xenstore-domain
tools/helpers/xen-init-dom0
@@ -41,3 +41,17 @@ Use the x86 instruction emulator fuzzer as an example.
$ $AFLPATH/afl-fuzz -t 1000 -i testcase_dir -o findings_dir -- ./afl-harness
Please see AFL documentation for more information.
+
+# GENERATING COVERAGE INFORMATION
+
+To use afl-cov or gcov, you need a separate binary instrumented to
+generate coverage data. To do this, use the target `afl-cov`:
+
+ $ make afl-cov #produces afl-harness-cov
+
+NOTE: Please also note that the coverage instrumentation hard-codes
+the absolute path for the instrumentation read and write files in the
+binary; so coverage data will always show up in the build directory no
+matter where you run the binary from.
+
+Please see afl-cov and/or gcov documentation for more information.
\ No newline at end of file
@@ -23,19 +23,33 @@ x86_emulate_user.c x86_emulate_user.h: %:
CFLAGS += $(CFLAGS_xeninclude) -D__XEN_TOOLS__ -I.
+GCOV_FLAGS=--coverage
+
x86.h := asm/x86-vendors.h asm/x86-defns.h asm/msr-index.h
x86_emulate.h := x86_emulate_user.h x86_emulate/x86_emulate.h $(x86.h)
x86_emulate_user.o: x86_emulate_user.c x86_emulate/x86_emulate.c $(x86_emulate.h)
+x86_emulate_user-cov.o: x86_emulate_user.c x86_emulate/x86_emulate.c $(x86_emulate.h)
+ $(CC) -c $(CFLAGS) $(GCOV_FLAGS) -o $@ x86_emulate_user.c
+
fuzz-emul.o: $(x86_emulate.h)
+fuzz-emul-cov.o: fuzz-emul.c $(x86_emulate.h)
+ $(CC) -c $(CFLAGS) $(GCOV_FLAGS) -o $@ fuzz-emul.c
+
+afl-harness-cov.o: afl-harness.c
+ $(CC) -c $(CFLAGS) $(GCOV_FLAGS) $^ -o $@
+
x86-insn-fuzzer.a: fuzz-emul.o x86_emulate_user.o
$(AR) rc $@ $^
afl-harness: afl-harness.o fuzz-emul.o x86_emulate_user.o
$(CC) $(CFLAGS) $^ -o $@
+afl-harness-cov: afl-harness-cov.o fuzz-emul-cov.o x86_emulate_user-cov.o
+ $(CC) $(CFLAGS) $(GCOV_FLAGS) $^ -o $@
+
# Common targets
.PHONY: all
all: x86-insn-fuzz-all
@@ -46,7 +60,7 @@ distclean: clean
.PHONY: clean
clean:
- rm -f *.a *.o .*.d afl-harness
+ rm -f *.a *.o .*.d afl-harness afl-harness-cov *.gcda *.gcno *.gcov
.PHONY: install
install: all
@@ -55,3 +69,6 @@ install: all
.PHONY: afl
afl: afl-harness
+
+.PHONY: afl-cov
+afl-cov: afl-harness-cov
...to generate a "normal" coverage-instrumented binary, suitable for use with gcov or afl-cov. This is slightly annoying because: - Every object file needs to have been instrumented to work effectively - You generally want to have both an afl-instrumented binary and a gcov-instrumented binary at the same time, but - gcov instrumentation and afl instrumentation are mutually exclusive So when making the `afl-cov` target, generate a second set of object files and a second binary with the `-cov` suffix. Signed-off-by: George Dunlap <george.dunlap@citrix.com> --- CC: Ian Jackson <ian.jackson@citrix.com> CC: Wei Liu <wei.liu2@citrix.com> CC: Andrew Cooper <andrew.cooper3@citrix.com> CC: Jan Beulich <jbeulich@suse.com> --- .gitignore | 1 + tools/fuzz/README.afl | 14 ++++++++++++++ tools/fuzz/x86_instruction_emulator/Makefile | 19 ++++++++++++++++++- 3 files changed, 33 insertions(+), 1 deletion(-)