upload android base code part6

android/system/core/libbacktrace/UnwindPtrace.cpp

@@ -0,0 +1,186 @@
+/*
+ * 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.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <ucontext.h>
+
+#include <libunwind.h>
+#include <libunwind-ptrace.h>
+
+#include <backtrace/Backtrace.h>
+#include <backtrace/BacktraceMap.h>
+
+#include "BacktraceLog.h"
+#include "UnwindMap.h"
+#include "UnwindPtrace.h"
+
+UnwindPtrace::UnwindPtrace(pid_t pid, pid_t tid, BacktraceMap* map)
+    : BacktracePtrace(pid, tid, map), addr_space_(nullptr), upt_info_(nullptr) {
+}
+
+UnwindPtrace::~UnwindPtrace() {
+  if (upt_info_) {
+    _UPT_destroy(upt_info_);
+    upt_info_ = nullptr;
+  }
+
+  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_, nullptr);
+
+    unw_destroy_addr_space(addr_space_);
+    addr_space_ = nullptr;
+  }
+}
+
+bool UnwindPtrace::Init() {
+  if (upt_info_) {
+    return true;
+  }
+
+  if (addr_space_) {
+    // If somehow the addr_space_ gets initialized but upt_info_ doesn't,
+    // then that indicates there is some kind of failure.
+    return false;
+  }
+
+  addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
+  if (!addr_space_) {
+    BACK_LOGW("unw_create_addr_space failed.");
+    error_ = BACKTRACE_UNWIND_ERROR_SETUP_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.");
+    error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
+    return false;
+  }
+
+  return true;
+}
+
+bool UnwindPtrace::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) {
+  if (GetMap() == nullptr) {
+    // Without a map object, we can't do anything.
+    error_ = BACKTRACE_UNWIND_ERROR_MAP_MISSING;
+    return false;
+  }
+
+  error_ = BACKTRACE_UNWIND_NO_ERROR;
+
+  if (ucontext) {
+    BACK_LOGW("Unwinding from a specified context not supported yet.");
+    error_ = BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION;
+    return false;
+  }
+
+  if (!Init()) {
+    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);
+    error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
+    return false;
+  }
+
+  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;
+      }
+
+      FillInMap(frame->pc, &frame->map);
+      if (BacktraceMap::IsValid(frame->map)) {
+        frame->rel_pc = frame->pc - frame->map.start + frame->map.load_bias;
+      } else {
+        frame->rel_pc = frame->pc;
+      }
+
+      frame->func_name = GetFunctionName(frame->pc, &frame->func_offset, &frame->map);
+
+      num_frames++;
+      // If the pc is in a device map, then don't try to step.
+      if (frame->map.flags & PROT_DEVICE_MAP) {
+        break;
+      }
+    } else {
+      // If the pc is in a device map, then don't try to step.
+      backtrace_map_t map;
+      FillInMap(pc, &map);
+      if (map.flags & PROT_DEVICE_MAP) {
+        break;
+      }
+      num_ignore_frames--;
+    }
+    // Verify the sp is not in a device map.
+    backtrace_map_t map;
+    FillInMap(sp, &map);
+    if (map.flags & PROT_DEVICE_MAP) {
+      break;
+    }
+    ret = unw_step (&cursor);
+  } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
+
+  return true;
+}
+
+std::string UnwindPtrace::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
+  if (!Init()) {
+    return "";
+  }
+
+  *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 "";
+}