1 /* 2 * Copyright (C) 2013 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <stdint.h> 18 #include <sys/types.h> 19 #include <ucontext.h> 20 21 #include <libunwind.h> 22 #include <libunwind-ptrace.h> 23 24 #include <backtrace/Backtrace.h> 25 #include <backtrace/BacktraceMap.h> 26 27 #include "BacktraceLog.h" 28 #include "UnwindMap.h" 29 #include "UnwindPtrace.h" 30 31 UnwindPtrace::UnwindPtrace(pid_t pid, pid_t tid, BacktraceMap* map) 32 : BacktracePtrace(pid, tid, map), addr_space_(nullptr), upt_info_(nullptr) { 33 } 34 35 UnwindPtrace::~UnwindPtrace() { 36 if (upt_info_) { 37 _UPT_destroy(upt_info_); 38 upt_info_ = nullptr; 39 } 40 if (addr_space_) { 41 // Remove the map from the address space before destroying it. 42 // It will be freed in the UnwindMap destructor. 43 unw_map_set(addr_space_, nullptr); 44 45 unw_destroy_addr_space(addr_space_); 46 addr_space_ = nullptr; 47 } 48 } 49 50 bool UnwindPtrace::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) { 51 if (GetMap() == nullptr) { 52 // Without a map object, we can't do anything. 53 error_ = BACKTRACE_UNWIND_ERROR_MAP_MISSING; 54 return false; 55 } 56 57 error_ = BACKTRACE_UNWIND_NO_ERROR; 58 59 if (ucontext) { 60 BACK_LOGW("Unwinding from a specified context not supported yet."); 61 error_ = BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION; 62 return false; 63 } 64 65 addr_space_ = unw_create_addr_space(&_UPT_accessors, 0); 66 if (!addr_space_) { 67 BACK_LOGW("unw_create_addr_space failed."); 68 error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED; 69 return false; 70 } 71 72 UnwindMap* map = static_cast<UnwindMap*>(GetMap()); 73 unw_map_set(addr_space_, map->GetMapCursor()); 74 75 upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid())); 76 if (!upt_info_) { 77 BACK_LOGW("Failed to create upt info."); 78 error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED; 79 return false; 80 } 81 82 unw_cursor_t cursor; 83 int ret = unw_init_remote(&cursor, addr_space_, upt_info_); 84 if (ret < 0) { 85 BACK_LOGW("unw_init_remote failed %d", ret); 86 error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED; 87 return false; 88 } 89 90 size_t num_frames = 0; 91 do { 92 unw_word_t pc; 93 ret = unw_get_reg(&cursor, UNW_REG_IP, &pc); 94 if (ret < 0) { 95 BACK_LOGW("Failed to read IP %d", ret); 96 break; 97 } 98 unw_word_t sp; 99 ret = unw_get_reg(&cursor, UNW_REG_SP, &sp); 100 if (ret < 0) { 101 BACK_LOGW("Failed to read SP %d", ret); 102 break; 103 } 104 105 if (num_ignore_frames == 0) { 106 frames_.resize(num_frames+1); 107 backtrace_frame_data_t* frame = &frames_.at(num_frames); 108 frame->num = num_frames; 109 frame->pc = static_cast<uintptr_t>(pc); 110 frame->sp = static_cast<uintptr_t>(sp); 111 frame->stack_size = 0; 112 113 if (num_frames > 0) { 114 backtrace_frame_data_t* prev = &frames_.at(num_frames-1); 115 prev->stack_size = frame->sp - prev->sp; 116 } 117 118 frame->func_name = GetFunctionName(frame->pc, &frame->func_offset); 119 120 FillInMap(frame->pc, &frame->map); 121 122 num_frames++; 123 } else { 124 num_ignore_frames--; 125 } 126 ret = unw_step (&cursor); 127 } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES); 128 129 return true; 130 } 131 132 std::string UnwindPtrace::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) { 133 *offset = 0; 134 char buf[512]; 135 unw_word_t value; 136 if (unw_get_proc_name_by_ip(addr_space_, pc, buf, sizeof(buf), &value, 137 upt_info_) >= 0 && buf[0] != '\0') { 138 *offset = static_cast<uintptr_t>(value); 139 return buf; 140 } 141 return ""; 142 } 143
