Add x86 stack unwinding support to libcorkscrew.

Change-Id: I1d4f4b11b4c8bf517b1dd07afccbedc41a84fd1b

libcorkscrew/Android.mk

@@ -31,6 +31,12 @@ LOCAL_SRC_FILES += \
 LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH -DCORKSCREW_HAVE_LIBIBERTY
 LOCAL_LDFLAGS += -liberty
 endif
+ifeq ($(TARGET_ARCH),x86)
+LOCAL_SRC_FILES += \
+	arch-x86/backtrace-x86.c \
+	arch-x86/ptrace-x86.c
+LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH
+endif
 
 LOCAL_SHARED_LIBRARIES += libdl libcutils
 

libcorkscrew/arch-x86/backtrace-x86.c

@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Backtracing functions for x86.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "../backtrace-arch.h"
+#include "../backtrace-helper.h"
+#include <corkscrew/ptrace.h>
+
+#include <stdlib.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <limits.h>
+#include <errno.h>
+#include <sys/ptrace.h>
+#include <sys/exec_elf.h>
+#include <cutils/log.h>
+
+/* Machine context at the time a signal was raised. */
+typedef struct ucontext {
+    uint32_t uc_flags;
+    struct ucontext* uc_link;
+    stack_t uc_stack;
+    struct sigcontext {
+        uint32_t gs;
+        uint32_t fs;
+        uint32_t es;
+        uint32_t ds;
+        uint32_t edi;
+        uint32_t esi;
+        uint32_t ebp;
+        uint32_t esp;
+        uint32_t ebx;
+        uint32_t edx;
+        uint32_t ecx;
+        uint32_t eax;
+        uint32_t trapno;
+        uint32_t err;
+        uint32_t eip;
+        uint32_t cs;
+        uint32_t efl;
+        uint32_t uesp;
+        uint32_t ss;
+        void* fpregs;
+        uint32_t oldmask;
+        uint32_t cr2;
+    } uc_mcontext;
+    uint32_t uc_sigmask;
+} ucontext_t;
+
+/* Unwind state. */
+typedef struct {
+    uint32_t ebp;
+    uint32_t eip;
+    uint32_t esp;
+} unwind_state_t;
+
+static ssize_t unwind_backtrace_common(pid_t tid, const ptrace_context_t* context,
+        unwind_state_t* state, backtrace_frame_t* backtrace,
+        size_t ignore_depth, size_t max_depth) {
+    size_t ignored_frames = 0;
+    size_t returned_frames = 0;
+
+    while (state->ebp && returned_frames < max_depth) {
+        backtrace_frame_t* frame = add_backtrace_entry(state->eip,
+                backtrace, ignore_depth, max_depth,
+                &ignored_frames, &returned_frames);
+        uint32_t next_esp = state->ebp + 8;
+        if (frame) {
+            frame->stack_top = state->esp;
+            if (state->esp < next_esp) {
+                frame->stack_size = next_esp - state->esp;
+            }
+        }
+        state->esp = next_esp;
+        if (!try_get_word(tid, state->ebp + 4, &state->eip)
+                || !try_get_word(tid, state->ebp, &state->ebp)
+                || !state->eip) {
+            break;
+        }
+    }
+
+    return returned_frames;
+}
+
+ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext,
+        backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+    const ucontext_t* uc = (const ucontext_t*)sigcontext;
+
+    unwind_state_t state;
+    state.ebp = uc->uc_mcontext.ebp;
+    state.eip = uc->uc_mcontext.eip;
+    state.esp = uc->uc_mcontext.esp;
+
+    return unwind_backtrace_common(-1, NULL, &state, backtrace, ignore_depth, max_depth);
+}
+
+ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context,
+        backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+    pt_regs_x86_t regs;
+    if (ptrace(PTRACE_GETREGS, tid, 0, &regs)) {
+        return -1;
+    }
+
+    unwind_state_t state;
+    state.ebp = regs.ebp;
+    state.eip = regs.eip;
+    state.esp = regs.esp;
+
+    return unwind_backtrace_common(tid, context, &state, backtrace, ignore_depth, max_depth);
+}

libcorkscrew/arch-x86/ptrace-x86.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "../ptrace-arch.h"
+
+#include <cutils/log.h>
+
+void load_ptrace_map_info_data_arch(pid_t pid, map_info_t* mi, map_info_data_t* data) {
+}
+
+void free_ptrace_map_info_data_arch(map_info_t* mi, map_info_data_t* data) {
+}