1 files changed, 487 insertions, 0 deletions
diff --git a/externals/breakpad/src/processor/disassembler_objdump.cc b/externals/breakpad/src/processor/disassembler_objdump.cc
new file mode 100644
index 0000000000..9f9569a5e6
--- /dev/null
+++ b/externals/breakpad/src/processor/disassembler_objdump.cc
@@ -0,0 +1,487 @@
+// Copyright (c) 2022, Google LLC
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google LLC nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// disassembler_objdump.: Disassembler that invokes objdump for disassembly.
+//
+// Author: Mark Brand
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>  // Must come first
+#endif
+
+#include "processor/disassembler_objdump.h"
+
+#include <unistd.h>
+#include <sys/wait.h>
+
+#include <array>
+#include <fstream>
+#include <iostream>
+#include <iterator>
+#include <regex>
+#include <sstream>
+#include <vector>
+
+#include "common/linux/eintr_wrapper.h"
+#include "common/linux/scoped_pipe.h"
+#include "common/linux/scoped_tmpfile.h"
+#include "processor/logging.h"
+
+namespace google_breakpad {
+namespace {
+
+const size_t kMaxX86InstructionLength = 15;
+
+bool IsInstructionPrefix(const string& token) {
+  if (token == "lock" || token == "rep" || token == "repz" ||
+      token == "repnz") {
+    return true;
+  }
+  return false;
+}
+
+bool IsOperandSize(const string& token) {
+  if (token == "BYTE" || token == "WORD" || token == "DWORD" ||
+      token == "QWORD" || token == "PTR") {
+    return true;
+  }
+  return false;
+}
+
+bool GetSegmentAddressX86(const DumpContext& context, string segment_name,
+                          uint64_t& address) {
+  if (segment_name == "ds") {
+    address = context.GetContextX86()->ds;
+  } else if (segment_name == "es") {
+    address = context.GetContextX86()->es;
+  } else if (segment_name == "fs") {
+    address = context.GetContextX86()->fs;
+  } else if (segment_name == "gs") {
+    address = context.GetContextX86()->gs;
+  } else {
+    BPLOG(ERROR) << "Unsupported segment register: " << segment_name;
+    return false;
+  }
+
+  return true;
+}
+
+bool GetSegmentAddressAMD64(const DumpContext& context, string segment_name,
+                            uint64_t& address) {
+  if (segment_name == "ds") {
+    address = 0;
+  } else if (segment_name == "es") {
+    address = 0;
+  } else {
+    BPLOG(ERROR) << "Unsupported segment register: " << segment_name;
+    return false;
+  }
+
+  return true;
+}
+
+bool GetSegmentAddress(const DumpContext& context, string segment_name,
+                       uint64_t& address) {
+  if (context.GetContextCPU() == MD_CONTEXT_X86) {
+    return GetSegmentAddressX86(context, segment_name, address);
+  } else if (context.GetContextCPU() == MD_CONTEXT_AMD64) {
+    return GetSegmentAddressAMD64(context, segment_name, address);
+  } else {
+    BPLOG(ERROR) << "Unsupported architecture for GetSegmentAddress\n";
+    return false;
+  }
+}
+
+bool GetRegisterValueX86(const DumpContext& context, string register_name,
+                         uint64_t& value) {
+  if (register_name == "eax") {
+    value = context.GetContextX86()->eax;
+  } else if (register_name == "ebx") {
+    value = context.GetContextX86()->ebx;
+  } else if (register_name == "ecx") {
+    value = context.GetContextX86()->ecx;
+  } else if (register_name == "edx") {
+    value = context.GetContextX86()->edx;
+  } else if (register_name == "edi") {
+    value = context.GetContextX86()->edi;
+  } else if (register_name == "esi") {
+    value = context.GetContextX86()->esi;
+  } else if (register_name == "ebp") {
+    value = context.GetContextX86()->ebp;
+  } else if (register_name == "esp") {
+    value = context.GetContextX86()->esp;
+  } else if (register_name == "eip") {
+    value = context.GetContextX86()->eip;
+  } else {
+    BPLOG(ERROR) << "Unsupported register: " << register_name;
+    return false;
+  }
+
+  return true;
+}
+
+bool GetRegisterValueAMD64(const DumpContext& context, string register_name,
+                           uint64_t& value) {
+  if (register_name == "rax") {
+    value = context.GetContextAMD64()->rax;
+  } else if (register_name == "rbx") {
+    value = context.GetContextAMD64()->rbx;
+  } else if (register_name == "rcx") {
+    value = context.GetContextAMD64()->rcx;
+  } else if (register_name == "rdx") {
+    value = context.GetContextAMD64()->rdx;
+  } else if (register_name == "rdi") {
+    value = context.GetContextAMD64()->rdi;
+  } else if (register_name == "rsi") {
+    value = context.GetContextAMD64()->rsi;
+  } else if (register_name == "rbp") {
+    value = context.GetContextAMD64()->rbp;
+  } else if (register_name == "rsp") {
+    value = context.GetContextAMD64()->rsp;
+  } else if (register_name == "r8") {
+    value = context.GetContextAMD64()->r8;
+  } else if (register_name == "r9") {
+    value = context.GetContextAMD64()->r9;
+  } else if (register_name == "r10") {
+    value = context.GetContextAMD64()->r10;
+  } else if (register_name == "r11") {
+    value = context.GetContextAMD64()->r11;
+  } else if (register_name == "r12") {
+    value = context.GetContextAMD64()->r12;
+  } else if (register_name == "r13") {
+    value = context.GetContextAMD64()->r13;
+  } else if (register_name == "r14") {
+    value = context.GetContextAMD64()->r14;
+  } else if (register_name == "r15") {
+    value = context.GetContextAMD64()->r15;
+  } else if (register_name == "rip") {
+    value = context.GetContextAMD64()->rip;
+  } else {
+    BPLOG(ERROR) << "Unsupported register: " << register_name;
+    return false;
+  }
+
+  return true;
+}
+
+// Lookup the value of `register_name` in `context`, store it into `value` on
+// success.
+// Support for non-full-size registers not implemented, since we're only using
+// this to evaluate address expressions.
+bool GetRegisterValue(const DumpContext& context, string register_name,
+                      uint64_t& value) {
+  if (context.GetContextCPU() == MD_CONTEXT_X86) {
+    return GetRegisterValueX86(context, register_name, value);
+  } else if (context.GetContextCPU() == MD_CONTEXT_AMD64) {
+    return GetRegisterValueAMD64(context, register_name, value);
+  } else {
+    BPLOG(ERROR) << "Unsupported architecture for GetRegisterValue\n";
+    return false;
+  }
+}
+}  // namespace
+
+// static
+bool DisassemblerObjdump::DisassembleInstruction(uint32_t cpu,
+                                                 const uint8_t* raw_bytes,
+                                                 unsigned int raw_bytes_len,
+                                                 string& instruction) {
+  // Always initialize outputs
+  instruction = "";
+
+  if (!raw_bytes || raw_bytes_len == 0) {
+    // There's no need to perform any operation in this case, as there's
+    // clearly no instruction there.
+    return false;
+  }
+
+  string architecture;
+  if (cpu == MD_CONTEXT_X86) {
+    architecture = "i386";
+  } else if (cpu == MD_CONTEXT_AMD64) {
+    architecture = "i386:x86-64";
+  } else {
+    BPLOG(ERROR) << "Unsupported architecture.";
+    return false;
+  }
+
+  // Create a temporary file for the raw instruction bytes to pass to
+  // objdump, and write the bytes to the input file.
+  ScopedTmpFile raw_bytes_file;
+  if (!raw_bytes_file.InitData(raw_bytes, raw_bytes_len)) {
+    BPLOG(ERROR) << "Failed creating temporary file.";
+    return false;
+  }
+
+  // Create a pipe to use to read the disassembly back from objdump.
+  ScopedPipe disassembly_pipe;
+  if (!disassembly_pipe.Init()) {
+    BPLOG(ERROR) << "Failed creating pipe for output.";
+    return false;
+  }
+
+  pid_t child_pid = fork();
+  if (child_pid < 0) {
+    BPLOG(ERROR) << "Fork failed.";
+    return false;
+  }
+
+  if (child_pid == 0) {
+    // In the child process, set up the input and output file descriptors.
+    if (dup2(raw_bytes_file.GetFd(), STDIN_FILENO) < 0 ||
+        disassembly_pipe.Dup2WriteFd(STDOUT_FILENO) < 0 ||
+        disassembly_pipe.Dup2WriteFd(STDERR_FILENO) < 0) {
+      BPLOG(ERROR) << "Failed dup'ing file descriptors.";
+      exit(-1);
+    }
+
+    // We need to close the read end of the pipe in the child process so that
+    // when the parent closes it, the pipe is disconnected.
+    disassembly_pipe.CloseReadFd();
+
+    // We use "/proc/self/fd/0" here to allow objdump to parse an unnamed file,
+    // since objdump does not have a mode to read from stdin. This cannot be
+    // used with a pipe, since objdump requires that the input is a standard
+    // file.
+    execlp("objdump", "objdump", "-D", "--no-show-raw-insn", "-b", "binary",
+           "-M", "intel", "-m", architecture.c_str(), "/proc/self/fd/0",
+           nullptr);
+
+    BPLOG(ERROR) << "Failed to exec objdump.";
+    exit(-1);
+  } else {
+    // In the parent process, parse the objdump output.
+
+    // Match the instruction line, from:
+    //    0:        lock cmpxchg DWORD PTR [esi+0x10],eax
+    // extract the string "lock cmpxchg DWORD PTR [esi+0x10],eax"
+    std::regex instruction_regex(
+        "^\\s+[0-9a-f]+:\\s+"  // "   0:"
+        "((?:\\s*\\S*)+)$");   // "lock cmpxchg..."
+
+    std::string line;
+    std::smatch match;
+    while (disassembly_pipe.ReadLine(line)) {
+      if (std::regex_match(line, match, instruction_regex)) {
+        instruction = match[1].str();
+        break;
+      }
+    }
+
+    // Close the read pipe so that objdump will exit (in case we broke out of
+    // the loop above before reading all of the output).
+    disassembly_pipe.CloseReadFd();
+
+    // Now wait for objdump to exit.
+    int status = 0;
+    HANDLE_EINTR(waitpid(child_pid, &status, 0));
+
+    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+      BPLOG(ERROR) << "objdump didn't run successfully.";
+      return false;
+    }
+
+    if (instruction == "") {
+      BPLOG(ERROR) << "Failed to find instruction in objdump output.";
+      return false;
+    }
+  }
+
+  return true;
+}
+
+// static
+bool DisassemblerObjdump::TokenizeInstruction(const string& instruction,
+                                              string& operation, string& dest,
+                                              string& src) {
+  // Always initialize outputs.
+  operation = "";
+  dest = "";
+  src = "";
+
+  // Split the instruction into tokens by either whitespace or comma.
+  std::regex token_regex("((?:[^\\s,]+)|,)(?:\\s)*");
+  std::sregex_iterator tokens_begin(instruction.begin(), instruction.end(),
+                                    token_regex);
+
+  bool found_comma = false;
+  for (auto tokens_iter = tokens_begin; tokens_iter != std::sregex_iterator();
+       ++tokens_iter) {
+    auto token = (*tokens_iter)[1].str();
+    if (operation.size() == 0) {
+      if (IsInstructionPrefix(token))
+        continue;
+      operation = token;
+    } else if (dest.size() == 0) {
+      if (IsOperandSize(token))
+        continue;
+      dest = token;
+    } else if (!found_comma) {
+      if (token == ",") {
+        found_comma = true;
+      } else {
+        BPLOG(ERROR) << "Failed to parse operands from objdump output, expected"
+                        " comma but found \""
+                     << token << "\"";
+        return false;
+      }
+    } else if (src.size() == 0) {
+      if (IsOperandSize(token))
+        continue;
+      src = token;
+    } else {
+      if (token == ",") {
+        BPLOG(ERROR) << "Failed to parse operands from objdump output, found "
+                        "unexpected comma after last operand.";
+        return false;
+      } else {
+        // We just ignore other junk after the last operand unless it's a
+        // comma, which would indicate we're probably still in the middle
+        // of the operands and something has gone wrong
+      }
+    }
+  }
+
+  if (found_comma && src.size() == 0) {
+    BPLOG(ERROR) << "Failed to parse operands from objdump output, found comma "
+                    "but no src operand.";
+    return false;
+  }
+
+  return true;
+}
+
+// static
+bool DisassemblerObjdump::CalculateAddress(const DumpContext& context,
+                                           const string& expression,
+                                           uint64_t& address) {
+  address = 0;
+
+  // Extract the components of the expression.
+  // fs:[esi+edi*4+0x80] -> ["fs", "esi", "edi", "4", "-", "0x80"]
+  std::regex expression_regex(
+      "^(?:(\\ws):)?"                // "fs:"
+      "\\[(\\w+)"                    // "[esi"
+      "(?:\\+(\\w+)(?:\\*(\\d+)))?"  // "+edi*4"
+      "(?:([\\+-])(0x[0-9a-f]+))?"   // "-0x80"
+      "\\]$");                       // "]"
+
+  std::smatch match;
+  if (!std::regex_match(expression, match, expression_regex) ||
+      match.size() != 7) {
+    return false;
+  }
+
+  string segment_name = match[1].str();
+  string register_name = match[2].str();
+  string index_name = match[3].str();
+  string index_stride = match[4].str();
+  string offset_sign = match[5].str();
+  string offset = match[6].str();
+
+  uint64_t segment_address = 0;
+  uint64_t register_value = 0;
+  uint64_t index_value = 0;
+  uint64_t index_stride_value = 1;
+  uint64_t offset_value = 0;
+
+  if (segment_name.size() &&
+      !GetSegmentAddress(context, segment_name, segment_address)) {
+    return false;
+  }
+
+  if (!GetRegisterValue(context, register_name, register_value)) {
+    return false;
+  }
+
+  if (index_name.size() &&
+      !GetRegisterValue(context, index_name, index_value)) {
+    return false;
+  }
+
+  if (index_stride.size()) {
+    index_stride_value = strtoull(index_stride.c_str(), nullptr, 0);
+  }
+
+  if (offset.size()) {
+    offset_value = strtoull(offset.c_str(), nullptr, 0);
+  }
+
+  address =
+      segment_address + register_value + (index_value * index_stride_value);
+  if (offset_sign == "+") {
+    address += offset_value;
+  } else if (offset_sign == "-") {
+    address -= offset_value;
+  }
+
+  return true;
+}
+
+DisassemblerObjdump::DisassemblerObjdump(const uint32_t cpu,
+                                         const MemoryRegion* memory_region,
+                                         uint64_t address) {
+  if (address < memory_region->GetBase() ||
+      memory_region->GetBase() + memory_region->GetSize() <= address) {
+    return;
+  }
+
+  uint8_t ip_bytes[kMaxX86InstructionLength] = {0};
+  size_t ip_bytes_length;
+  for (ip_bytes_length = 0; ip_bytes_length < kMaxX86InstructionLength;
+       ++ip_bytes_length) {
+    // We have to read byte-by-byte here, since we still want to try and
+    // disassemble an instruction even if we don't have enough bytes.
+    if (!memory_region->GetMemoryAtAddress(address + ip_bytes_length,
+                                           &ip_bytes[ip_bytes_length])) {
+      break;
+    }
+  }
+
+  string instruction;
+  if (!DisassembleInstruction(cpu, ip_bytes, kMaxX86InstructionLength,
+                              instruction)) {
+    return;
+  }
+
+  if (!TokenizeInstruction(instruction, operation_, dest_, src_)) {
+    return;
+  }
+}
+
+bool DisassemblerObjdump::CalculateSrcAddress(const DumpContext& context,
+                                              uint64_t& address) {
+  return CalculateAddress(context, src_, address);
+}
+
+bool DisassemblerObjdump::CalculateDestAddress(const DumpContext& context,
+                                               uint64_t& address) {
+  return CalculateAddress(context, dest_, address);
+}
+
+}  // namespace google_breakpad
+\ No newline at end of file