Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2016 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 <errno.h> |
| 18 | #include <fcntl.h> |
| 19 | #include <sys/mman.h> |
| 20 | #include <sys/ptrace.h> |
| 21 | #include <sys/stat.h> |
| 22 | #include <sys/types.h> |
| 23 | #include <sys/uio.h> |
| 24 | #include <unistd.h> |
| 25 | |
| 26 | #include <algorithm> |
| 27 | #include <memory> |
| 28 | |
| 29 | #include <android-base/unique_fd.h> |
| 30 | |
Christopher Ferris | d226a51 | 2017-07-14 10:37:19 -0700 | [diff] [blame^] | 31 | #include <unwindstack/Memory.h> |
| 32 | |
| 33 | #include "Check.h" |
| 34 | |
| 35 | namespace unwindstack { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 36 | |
| 37 | bool Memory::ReadString(uint64_t addr, std::string* string, uint64_t max_read) { |
| 38 | string->clear(); |
| 39 | uint64_t bytes_read = 0; |
| 40 | while (bytes_read < max_read) { |
| 41 | uint8_t value; |
| 42 | if (!Read(addr, &value, sizeof(value))) { |
| 43 | return false; |
| 44 | } |
| 45 | if (value == '\0') { |
| 46 | return true; |
| 47 | } |
| 48 | string->push_back(value); |
| 49 | addr++; |
| 50 | bytes_read++; |
| 51 | } |
| 52 | return false; |
| 53 | } |
| 54 | |
Christopher Ferris | 3958f80 | 2017-02-01 15:44:40 -0800 | [diff] [blame] | 55 | bool MemoryBuffer::Read(uint64_t addr, void* dst, size_t size) { |
| 56 | uint64_t last_read_byte; |
| 57 | if (__builtin_add_overflow(size, addr, &last_read_byte)) { |
| 58 | return false; |
| 59 | } |
| 60 | if (last_read_byte > raw_.size()) { |
| 61 | return false; |
| 62 | } |
| 63 | memcpy(dst, &raw_[addr], size); |
| 64 | return true; |
| 65 | } |
| 66 | |
| 67 | uint8_t* MemoryBuffer::GetPtr(size_t offset) { |
| 68 | if (offset < raw_.size()) { |
| 69 | return &raw_[offset]; |
| 70 | } |
| 71 | return nullptr; |
| 72 | } |
| 73 | |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 74 | MemoryFileAtOffset::~MemoryFileAtOffset() { |
Christopher Ferris | 3958f80 | 2017-02-01 15:44:40 -0800 | [diff] [blame] | 75 | Clear(); |
| 76 | } |
| 77 | |
| 78 | void MemoryFileAtOffset::Clear() { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 79 | if (data_) { |
| 80 | munmap(&data_[-offset_], size_ + offset_); |
| 81 | data_ = nullptr; |
| 82 | } |
| 83 | } |
| 84 | |
Christopher Ferris | 3958f80 | 2017-02-01 15:44:40 -0800 | [diff] [blame] | 85 | bool MemoryFileAtOffset::Init(const std::string& file, uint64_t offset, uint64_t size) { |
| 86 | // Clear out any previous data if it exists. |
| 87 | Clear(); |
| 88 | |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 89 | android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(file.c_str(), O_RDONLY | O_CLOEXEC))); |
| 90 | if (fd == -1) { |
| 91 | return false; |
| 92 | } |
| 93 | struct stat buf; |
| 94 | if (fstat(fd, &buf) == -1) { |
| 95 | return false; |
| 96 | } |
| 97 | if (offset >= static_cast<uint64_t>(buf.st_size)) { |
| 98 | return false; |
| 99 | } |
| 100 | |
| 101 | offset_ = offset & (getpagesize() - 1); |
| 102 | uint64_t aligned_offset = offset & ~(getpagesize() - 1); |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 103 | if (aligned_offset > static_cast<uint64_t>(buf.st_size) || |
| 104 | offset > static_cast<uint64_t>(buf.st_size)) { |
| 105 | return false; |
| 106 | } |
| 107 | |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 108 | size_ = buf.st_size - aligned_offset; |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 109 | uint64_t max_size; |
| 110 | if (!__builtin_add_overflow(size, offset_, &max_size) && max_size < size_) { |
Christopher Ferris | 3958f80 | 2017-02-01 15:44:40 -0800 | [diff] [blame] | 111 | // Truncate the mapped size. |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 112 | size_ = max_size; |
Christopher Ferris | 3958f80 | 2017-02-01 15:44:40 -0800 | [diff] [blame] | 113 | } |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 114 | void* map = mmap(nullptr, size_, PROT_READ, MAP_PRIVATE, fd, aligned_offset); |
| 115 | if (map == MAP_FAILED) { |
| 116 | return false; |
| 117 | } |
| 118 | |
| 119 | data_ = &reinterpret_cast<uint8_t*>(map)[offset_]; |
| 120 | size_ -= offset_; |
| 121 | |
| 122 | return true; |
| 123 | } |
| 124 | |
| 125 | bool MemoryFileAtOffset::Read(uint64_t addr, void* dst, size_t size) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 126 | uint64_t max_size; |
| 127 | if (__builtin_add_overflow(addr, size, &max_size) || max_size > size_) { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 128 | return false; |
| 129 | } |
| 130 | memcpy(dst, &data_[addr], size); |
| 131 | return true; |
| 132 | } |
| 133 | |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 134 | bool MemoryRemote::PtraceRead(uint64_t addr, long* value) { |
Christopher Ferris | 3958f80 | 2017-02-01 15:44:40 -0800 | [diff] [blame] | 135 | #if !defined(__LP64__) |
| 136 | // Cannot read an address greater than 32 bits. |
| 137 | if (addr > UINT32_MAX) { |
| 138 | return false; |
| 139 | } |
| 140 | #endif |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 141 | // ptrace() returns -1 and sets errno when the operation fails. |
| 142 | // To disambiguate -1 from a valid result, we clear errno beforehand. |
| 143 | errno = 0; |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 144 | *value = ptrace(PTRACE_PEEKTEXT, pid_, reinterpret_cast<void*>(addr), nullptr); |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 145 | if (*value == -1 && errno) { |
| 146 | return false; |
| 147 | } |
| 148 | return true; |
| 149 | } |
| 150 | |
| 151 | bool MemoryRemote::Read(uint64_t addr, void* dst, size_t bytes) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 152 | // Make sure that there is no overflow. |
| 153 | uint64_t max_size; |
| 154 | if (__builtin_add_overflow(addr, bytes, &max_size)) { |
| 155 | return false; |
| 156 | } |
| 157 | |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 158 | size_t bytes_read = 0; |
| 159 | long data; |
| 160 | size_t align_bytes = addr & (sizeof(long) - 1); |
| 161 | if (align_bytes != 0) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 162 | if (!PtraceRead(addr & ~(sizeof(long) - 1), &data)) { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 163 | return false; |
| 164 | } |
| 165 | size_t copy_bytes = std::min(sizeof(long) - align_bytes, bytes); |
| 166 | memcpy(dst, reinterpret_cast<uint8_t*>(&data) + align_bytes, copy_bytes); |
| 167 | addr += copy_bytes; |
| 168 | dst = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(dst) + copy_bytes); |
| 169 | bytes -= copy_bytes; |
| 170 | bytes_read += copy_bytes; |
| 171 | } |
| 172 | |
| 173 | for (size_t i = 0; i < bytes / sizeof(long); i++) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 174 | if (!PtraceRead(addr, &data)) { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 175 | return false; |
| 176 | } |
| 177 | memcpy(dst, &data, sizeof(long)); |
| 178 | dst = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(dst) + sizeof(long)); |
| 179 | addr += sizeof(long); |
| 180 | bytes_read += sizeof(long); |
| 181 | } |
| 182 | |
| 183 | size_t left_over = bytes & (sizeof(long) - 1); |
| 184 | if (left_over) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 185 | if (!PtraceRead(addr, &data)) { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 186 | return false; |
| 187 | } |
| 188 | memcpy(dst, &data, left_over); |
| 189 | bytes_read += left_over; |
| 190 | } |
| 191 | return true; |
| 192 | } |
| 193 | |
| 194 | bool MemoryLocal::Read(uint64_t addr, void* dst, size_t size) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 195 | // Make sure that there is no overflow. |
| 196 | uint64_t max_size; |
| 197 | if (__builtin_add_overflow(addr, size, &max_size)) { |
| 198 | return false; |
| 199 | } |
| 200 | |
| 201 | // The process_vm_readv call will not always work on remote |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 202 | // processes, so only use it for reads from the current pid. |
| 203 | // Use this method to avoid crashes if an address is invalid since |
| 204 | // unwind data could try to access any part of the address space. |
| 205 | struct iovec local_io; |
| 206 | local_io.iov_base = dst; |
| 207 | local_io.iov_len = size; |
| 208 | |
| 209 | struct iovec remote_io; |
| 210 | remote_io.iov_base = reinterpret_cast<void*>(static_cast<uintptr_t>(addr)); |
| 211 | remote_io.iov_len = size; |
| 212 | |
| 213 | ssize_t bytes_read = process_vm_readv(getpid(), &local_io, 1, &remote_io, 1, 0); |
| 214 | if (bytes_read == -1) { |
| 215 | return false; |
| 216 | } |
| 217 | return static_cast<size_t>(bytes_read) == size; |
| 218 | } |
| 219 | |
| 220 | bool MemoryOffline::Init(const std::string& file, uint64_t offset) { |
| 221 | if (!MemoryFileAtOffset::Init(file, offset)) { |
| 222 | return false; |
| 223 | } |
| 224 | // The first uint64_t value is the start of memory. |
| 225 | if (!MemoryFileAtOffset::Read(0, &start_, sizeof(start_))) { |
| 226 | return false; |
| 227 | } |
| 228 | // Subtract the first 64 bit value from the total size. |
| 229 | size_ -= sizeof(start_); |
| 230 | return true; |
| 231 | } |
| 232 | |
| 233 | bool MemoryOffline::Read(uint64_t addr, void* dst, size_t size) { |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 234 | uint64_t max_size; |
| 235 | if (__builtin_add_overflow(addr, size, &max_size)) { |
| 236 | return false; |
| 237 | } |
| 238 | |
| 239 | uint64_t real_size; |
| 240 | if (__builtin_add_overflow(start_, offset_, &real_size) || |
| 241 | __builtin_add_overflow(real_size, size_, &real_size)) { |
| 242 | return false; |
| 243 | } |
| 244 | |
| 245 | if (addr < start_ || max_size > real_size) { |
Christopher Ferris | 723cf9b | 2017-01-19 20:08:48 -0800 | [diff] [blame] | 246 | return false; |
| 247 | } |
| 248 | memcpy(dst, &data_[addr + offset_ - start_ + sizeof(start_)], size); |
| 249 | return true; |
| 250 | } |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 251 | |
Christopher Ferris | d226a51 | 2017-07-14 10:37:19 -0700 | [diff] [blame^] | 252 | MemoryRange::MemoryRange(Memory* memory, uint64_t begin, uint64_t end) |
| 253 | : memory_(memory), begin_(begin), length_(end - begin) { |
| 254 | CHECK(end > begin); |
| 255 | } |
| 256 | |
Christopher Ferris | f447c8e | 2017-04-03 12:39:47 -0700 | [diff] [blame] | 257 | bool MemoryRange::Read(uint64_t addr, void* dst, size_t size) { |
| 258 | uint64_t max_read; |
| 259 | if (__builtin_add_overflow(addr, size, &max_read) || max_read > length_) { |
| 260 | return false; |
| 261 | } |
| 262 | // The check above guarantees that addr + begin_ will not overflow. |
| 263 | return memory_->Read(addr + begin_, dst, size); |
| 264 | } |
Christopher Ferris | d226a51 | 2017-07-14 10:37:19 -0700 | [diff] [blame^] | 265 | |
| 266 | } // namespace unwindstack |