Implement Android Linux PTRACE support

* Fork upstream libunwind and cross-compile with Android NDK
* libunwind is also used for proc symbol resolve instead of bfd
* Replace BDF lib with capstone for disassembling actions
* Engineer build & patch scripts to support Android ARM, ARM64, x86, x86_64
* Rename linux/ptrace.* to linux/ptrace_utils.* since it conflicts with Android platform includes for ptrace API
* Wrap register & instruction sizes under macros to reflect sizes for supported CPU arch (makes debugging easier)
* Add / Implement missing definitions / functions for Android
* Improve Android build process

1 files changed, 89 insertions, 4 deletions

diff --git a/android/Android.mk b/android/Android.mk
index d1b60905..b11f09b7 100644
--- a/android/Android.mk
+++ b/android/Android.mk
@@ -14,18 +14,103 @@
 #   limitations under the License.
 
 LOCAL_PATH := $(abspath $(call my-dir)/..)
+
+# Enable Linux ptrace inesead of POSIX by default 
+ANDROID_WITH_PTRACE ?= true
+
+ifeq ($(APP_ABI),$(filter $(APP_ABI),armeabi armeabi-v7a))
+  ARCH_ABI := arm
+  UNW_ARCH := arm
+else ifeq ($(APP_ABI),$(filter $(APP_ABI),x86))
+  ARCH_ABI := x86
+  UNW_ARCH := x86
+  # TODO: Remove this when x86 testing is completed
+  $(info $(APP_ABI) Android not fully tested yet (consider providing feedback if tested))
+else ifeq ($(APP_ABI),$(filter $(APP_ABI),arm64-v8a))
+  ARCH_ABI := arm64
+  UNW_ARCH := aarch64
+  # TODO: Remove this when arm64 testing is completed
+  $(info $(APP_ABI) Android not fully tested yet (consider providing feedback if tested))
+else ifeq ($(APP_ABI),$(filter $(APP_ABI),x86_64))
+  ARCH_ABI := x86_64
+  UNW_ARCH := x86_64
+  $(error $(APP_ABI) Android not supported (issues with libunwind))
+else
+  # ndk-build will have already failed, so just in case
+  $(error Unknown APP_API '$(APP_ABI)')
+endif
+
+ifeq ($(ANDROID_WITH_PTRACE),true)
+  # Upstream libunwind compiled from sources with Android NDK toolchain
+  LIBUNWIND_A := third_party/android/libunwind/$(ARCH_ABI)/libunwind-$(UNW_ARCH).a
+  ifeq ("$(wildcard $(LIBUNWIND_A))","")
+    $(error libunwind-$(UNW_ARCH). is missing. Please execute \
+            'third_party/android/scripts/compile-libunwind.sh third_party/android/libunwind $(ARCH_ABI)')
+  endif
+
+  include $(CLEAR_VARS)
+  LOCAL_MODULE := libunwind
+  LOCAL_SRC_FILES := third_party/android/libunwind/$(ARCH_ABI)/libunwind.a
+  LOCAL_EXPORT_C_INCLUDES := third_party/android/libunwind/include
+  include $(PREBUILT_STATIC_LIBRARY)
+
+  include $(CLEAR_VARS)
+  LOCAL_MODULE := libunwind-arch
+  LOCAL_SRC_FILES := third_party/android/libunwind/$(ARCH_ABI)/libunwind-$(UNW_ARCH).a
+  LOCAL_EXPORT_C_INCLUDES := third_party/android/libunwind/include
+  include $(PREBUILT_STATIC_LIBRARY)
+
+  include $(CLEAR_VARS)
+  LOCAL_MODULE := libunwind-ptrace
+  LOCAL_SRC_FILES := third_party/android/libunwind/$(ARCH_ABI)/libunwind-ptrace.a
+  LOCAL_EXPORT_C_INCLUDES := third_party/android/libunwind/include
+  include $(PREBUILT_STATIC_LIBRARY)
+
+  LOCAL_MODULE := libunwind-dwarf-generic
+  LOCAL_SRC_FILES := third_party/android/libunwind/$(ARCH_ABI)/libunwind-dwarf-generic.a
+  LOCAL_EXPORT_C_INCLUDES := third_party/android/libunwind/include
+  include $(PREBUILT_STATIC_LIBRARY)
+
+  # Upstream capstone compiled from sources with Android NDK toolchain
+  LIBCAPSTONE_A := third_party/android/capstone/$(ARCH_ABI)/libcapstone.a
+  ifeq ("$(wildcard $(LIBCAPSTONE_A))","")
+    $(error libunwind-$(UNW_ARCH). is missing. Please execute \
+            'third_party/android/scripts/compile-capstone.sh third_party/android/capstone $(ARCH_ABI)')
+  endif
+  include $(CLEAR_VARS)
+  LOCAL_MODULE := libcapstone
+  LOCAL_SRC_FILES := $(LIBCAPSTONE_A)
+  LOCAL_EXPORT_C_INCLUDES := third_party/android/capstone/include
+  include $(PREBUILT_STATIC_LIBRARY)
+endif
+
+# Main honggfuzz module
 include $(CLEAR_VARS)
 
 LOCAL_MODULE := honggfuzz
 LOCAL_SRC_FILES := honggfuzz.c log.c files.c fuzz.c report.c mangle.c util.c
 LOCAL_CFLAGS := -std=c11 -I. \
     -D_GNU_SOURCE \
-    -Wall -Wextra -Wno-initializer-overrides -Wno-override-init -Wno-unknown-warning-option -Werror \
-    -funroll-loops -O2
+    -Wall -Wextra -Wno-initializer-overrides -Wno-override-init \
+    -Wno-unknown-warning-option -Werror -funroll-loops -O2
 LOCAL_LDFLAGS := -lm
 
-ARCH_SRCS := $(wildcard posix/*.c)
-ARCH = POSIX
+ifeq ($(ANDROID_WITH_PTRACE),true)
+  LOCAL_C_INCLUDES := third_party/android/libunwind/include third_party/android/capstone/include
+  LOCAL_STATIC_LIBRARIES := libunwind libunwind-arch libunwind-ptrace libunwind-dwarf-generic libcapstone
+  LOCAL_CFLAGS += -D__HF_USE_CAPSTONE__
+  ARCH_SRCS := linux/arch.c linux/ptrace_utils.c linux/perf.c linux/unwind.c
+  ARCH := LINUX
+  $(info $(shell (echo "********************************************************************")))
+  $(info $(shell (echo "Android PTRACE build: Will prevent debuggerd from processing crashes")))
+  $(info $(shell (echo "********************************************************************")))
+else
+  ARCH_SRCS := posix/arch.c
+  ARCH := POSIX
+  $(info $(shell (echo "********************************************************************")))
+  $(info $(shell (echo "Android POSIX build: Will allow debuggerd to process crashes")))
+  $(info $(shell (echo "********************************************************************")))
+endif
 
 LOCAL_SRC_FILES += $(ARCH_SRCS)
 LOCAL_CFLAGS += -D_HF_ARCH_${ARCH}