1 files changed, 133 insertions, 0 deletions
diff --git a/libbacktrace/UnwindPtrace.cpp b/libbacktrace/UnwindPtrace.cpp
new file mode 100644
index 0000000..732dae8
--- /dev/null
+++ b/libbacktrace/UnwindPtrace.cpp
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2013 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 "libbacktrace"
+
+#include <backtrace/Backtrace.h>
+#include <backtrace/BacktraceMap.h>
+
+#include <sys/types.h>
+#include <string.h>
+
+#include <libunwind.h>
+#include <libunwind-ptrace.h>
+
+#include "UnwindMap.h"
+#include "UnwindPtrace.h"
+
+UnwindPtrace::UnwindPtrace() : addr_space_(NULL), upt_info_(NULL) {
+}
+
+UnwindPtrace::~UnwindPtrace() {
+  if (upt_info_) {
+    _UPT_destroy(upt_info_);
+    upt_info_ = NULL;
+  }
+  if (addr_space_) {
+    // Remove the map from the address space before destroying it.
+    // It will be freed in the UnwindMap destructor.
+    unw_map_set(addr_space_, NULL);
+
+    unw_destroy_addr_space(addr_space_);
+    addr_space_ = NULL;
+  }
+}
+
+bool UnwindPtrace::Unwind(size_t num_ignore_frames) {
+  addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
+  if (!addr_space_) {
+    BACK_LOGW("unw_create_addr_space failed.");
+    return false;
+  }
+
+  UnwindMap* map = static_cast<UnwindMap*>(GetMap());
+  unw_map_set(addr_space_, map->GetMapCursor());
+
+  upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid()));
+  if (!upt_info_) {
+    BACK_LOGW("Failed to create upt info.");
+    return false;
+  }
+
+  unw_cursor_t cursor;
+  int ret = unw_init_remote(&cursor, addr_space_, upt_info_);
+  if (ret < 0) {
+    BACK_LOGW("unw_init_remote failed %d", ret);
+    return false;
+  }
+
+  std::vector<backtrace_frame_data_t>* frames = GetFrames();
+  frames->reserve(MAX_BACKTRACE_FRAMES);
+  size_t num_frames = 0;
+  do {
+    unw_word_t pc;
+    ret = unw_get_reg(&cursor, UNW_REG_IP, &pc);
+    if (ret < 0) {
+      BACK_LOGW("Failed to read IP %d", ret);
+      break;
+    }
+    unw_word_t sp;
+    ret = unw_get_reg(&cursor, UNW_REG_SP, &sp);
+    if (ret < 0) {
+      BACK_LOGW("Failed to read SP %d", ret);
+      break;
+    }
+
+    if (num_ignore_frames == 0) {
+      frames->resize(num_frames+1);
+      backtrace_frame_data_t* frame = &frames->at(num_frames);
+      frame->num = num_frames;
+      frame->pc = static_cast<uintptr_t>(pc);
+      frame->sp = static_cast<uintptr_t>(sp);
+      frame->stack_size = 0;
+
+      if (num_frames > 0) {
+        backtrace_frame_data_t* prev = &frames->at(num_frames-1);
+        prev->stack_size = frame->sp - prev->sp;
+      }
+
+      frame->func_name = GetFunctionName(frame->pc, &frame->func_offset);
+
+      frame->map = FindMap(frame->pc);
+
+      num_frames++;
+    } else {
+      num_ignore_frames--;
+    }
+    ret = unw_step (&cursor);
+  } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
+
+  return true;
+}
+
+std::string UnwindPtrace::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
+  *offset = 0;
+  char buf[512];
+  unw_word_t value;
+  if (unw_get_proc_name_by_ip(addr_space_, pc, buf, sizeof(buf), &value,
+                              upt_info_) >= 0 && buf[0] != '\0') {
+    *offset = static_cast<uintptr_t>(value);
+    return buf;
+  }
+  return "";
+}
+
+//-------------------------------------------------------------------------
+// C++ object creation function.
+//-------------------------------------------------------------------------
+Backtrace* CreatePtraceObj(pid_t pid, pid_t tid, BacktraceMap* map) {
+  return new BacktracePtrace(new UnwindPtrace(), pid, tid, map);
+}