Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 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 <errno.h> |
| 18 | #include <stdint.h> |
| 19 | #include <string.h> |
Christopher Ferris | 279843e | 2016-10-12 12:39:18 -0700 | [diff] [blame] | 20 | #include <sys/uio.h> |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 21 | #include <sys/param.h> |
| 22 | #include <sys/ptrace.h> |
| 23 | #include <sys/types.h> |
| 24 | #include <ucontext.h> |
| 25 | #include <unistd.h> |
| 26 | |
| 27 | #include <backtrace/Backtrace.h> |
| 28 | #include <backtrace/BacktraceMap.h> |
| 29 | |
| 30 | #include "BacktraceLog.h" |
| 31 | #include "BacktracePtrace.h" |
| 32 | #include "thread_utils.h" |
| 33 | |
| 34 | #if !defined(__APPLE__) |
| 35 | static bool PtraceRead(pid_t tid, uintptr_t addr, word_t* out_value) { |
| 36 | // ptrace() returns -1 and sets errno when the operation fails. |
| 37 | // To disambiguate -1 from a valid result, we clear errno beforehand. |
| 38 | errno = 0; |
| 39 | *out_value = ptrace(PTRACE_PEEKTEXT, tid, reinterpret_cast<void*>(addr), nullptr); |
| 40 | if (*out_value == static_cast<word_t>(-1) && errno) { |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 41 | return false; |
| 42 | } |
| 43 | return true; |
| 44 | } |
| 45 | #endif |
| 46 | |
| 47 | bool BacktracePtrace::ReadWord(uintptr_t ptr, word_t* out_value) { |
| 48 | #if defined(__APPLE__) |
| 49 | BACK_LOGW("MacOS does not support reading from another pid."); |
| 50 | return false; |
| 51 | #else |
| 52 | if (!VerifyReadWordArgs(ptr, out_value)) { |
| 53 | return false; |
| 54 | } |
| 55 | |
| 56 | backtrace_map_t map; |
| 57 | FillInMap(ptr, &map); |
| 58 | if (!BacktraceMap::IsValid(map) || !(map.flags & PROT_READ)) { |
| 59 | return false; |
| 60 | } |
| 61 | |
| 62 | return PtraceRead(Tid(), ptr, out_value); |
| 63 | #endif |
| 64 | } |
| 65 | |
| 66 | size_t BacktracePtrace::Read(uintptr_t addr, uint8_t* buffer, size_t bytes) { |
| 67 | #if defined(__APPLE__) |
| 68 | BACK_LOGW("MacOS does not support reading from another pid."); |
| 69 | return 0; |
| 70 | #else |
| 71 | backtrace_map_t map; |
| 72 | FillInMap(addr, &map); |
| 73 | if (!BacktraceMap::IsValid(map) || !(map.flags & PROT_READ)) { |
| 74 | return 0; |
| 75 | } |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 76 | bytes = MIN(map.end - addr, bytes); |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 77 | |
Christopher Ferris | 279843e | 2016-10-12 12:39:18 -0700 | [diff] [blame] | 78 | struct iovec local_io; |
| 79 | local_io.iov_base = buffer; |
| 80 | local_io.iov_len = bytes; |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 81 | |
Christopher Ferris | 279843e | 2016-10-12 12:39:18 -0700 | [diff] [blame] | 82 | struct iovec remote_io; |
| 83 | remote_io.iov_base = reinterpret_cast<void*>(addr); |
| 84 | remote_io.iov_len = bytes; |
| 85 | |
| 86 | ssize_t bytes_read = process_vm_readv(Tid(), &local_io, 1, &remote_io, 1, 0); |
| 87 | if (bytes_read == -1) { |
| 88 | return 0; |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 89 | } |
Christopher Ferris | 279843e | 2016-10-12 12:39:18 -0700 | [diff] [blame] | 90 | return static_cast<size_t>(bytes_read); |
Christopher Ferris | 2c43cff | 2015-03-26 19:18:36 -0700 | [diff] [blame] | 91 | #endif |
| 92 | } |