llvm-project

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//===-- sanitizer_symbolizer_mac.cpp --------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is shared between various sanitizers' runtime libraries.
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//
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// Implementation of Mac-specific "atos" symbolizer.
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//===----------------------------------------------------------------------===//
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#include "sanitizer_platform.h"
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#if SANITIZER_APPLE
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#  include <dlfcn.h>
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#  include <errno.h>
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#  include <stdlib.h>
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#  include <sys/wait.h>
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#  include <unistd.h>
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#  include <util.h>
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#  include "sanitizer_allocator_internal.h"
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#  include "sanitizer_mac.h"
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#  include "sanitizer_symbolizer_mac.h"
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namespace __sanitizer {
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bool DlAddrSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
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  Dl_info info;
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  int result = dladdr((const void *)addr, &info);
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  if (!result) return false;
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  // Compute offset if possible. `dladdr()` doesn't always ensure that `addr >=
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  // sym_addr` so only compute the offset when this holds. Failure to find the
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  // function offset is not treated as a failure because it might still be
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  // possible to get the symbol name.
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  uptr sym_addr = reinterpret_cast<uptr>(info.dli_saddr);
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  if (addr >= sym_addr) {
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    stack->info.function_offset = addr - sym_addr;
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  }
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  const char *demangled = DemangleSwiftAndCXX(info.dli_sname);
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  if (!demangled)
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    demangled = info.dli_sname;
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  stack->info.function = internal_strdup(demangled);
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  return true;
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}
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bool DlAddrSymbolizer::SymbolizeData(uptr addr, DataInfo *datainfo) {
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  Dl_info info;
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  int result = dladdr((const void *)addr, &info);
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  if (!result) return false;
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  const char *demangled = DemangleSwiftAndCXX(info.dli_sname);
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  if (!demangled)
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    demangled = info.dli_sname;
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  datainfo->name = internal_strdup(demangled);
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  datainfo->start = (uptr)info.dli_saddr;
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  return true;
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}
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class AtosSymbolizerProcess final : public SymbolizerProcess {
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 public:
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  explicit AtosSymbolizerProcess(const char *path)
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      : SymbolizerProcess(path, /*use_posix_spawn*/ true) {
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    pid_str_[0] = '\0';
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  }
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 private:
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  bool StartSymbolizerSubprocess() override {
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    // Put the string command line argument in the object so that it outlives
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    // the call to GetArgV.
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    internal_snprintf(pid_str_, sizeof(pid_str_), "%d", (int)internal_getpid());
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    // Configure sandbox before starting atos process.
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    return SymbolizerProcess::StartSymbolizerSubprocess();
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  }
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  bool ReachedEndOfOutput(const char *buffer, uptr length) const override {
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    return (length >= 1 && buffer[length - 1] == '\n');
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  }
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  void GetArgV(const char *path_to_binary,
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               const char *(&argv)[kArgVMax]) const override {
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    int i = 0;
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    argv[i++] = path_to_binary;
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    argv[i++] = "-p";
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    argv[i++] = &pid_str_[0];
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    if (GetMacosAlignedVersion() == MacosVersion(10, 9)) {
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      // On Mavericks atos prints a deprecation warning which we suppress by
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      // passing -d. The warning isn't present on other OSX versions, even the
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      // newer ones.
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      argv[i++] = "-d";
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    }
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    argv[i++] = nullptr;
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    CHECK_LE(i, kArgVMax);
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  }
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  char pid_str_[16];
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};
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#undef K_ATOS_ENV_VAR
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static bool ParseCommandOutput(const char *str, uptr addr, char **out_name,
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                               char **out_module, char **out_file, uptr *line,
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                               uptr *start_address) {
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  // Trim ending newlines.
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  char *trim;
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  ExtractTokenUpToDelimiter(str, "\n", &trim);
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  // The line from `atos` is in one of these formats:
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  //   myfunction (in library.dylib) (sourcefile.c:17)
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  //   myfunction (in library.dylib) + 0x1fe
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  //   myfunction (in library.dylib) + 15
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  //   0xdeadbeef (in library.dylib) + 0x1fe
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  //   0xdeadbeef (in library.dylib) + 15
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  //   0xdeadbeef (in library.dylib)
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  //   0xdeadbeef
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  const char *rest = trim;
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  char *symbol_name;
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  rest = ExtractTokenUpToDelimiter(rest, " (in ", &symbol_name);
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  if (rest[0] == '\0') {
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    InternalFree(symbol_name);
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    InternalFree(trim);
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    return false;
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  }
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  if (internal_strncmp(symbol_name, "0x", 2) != 0)
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    *out_name = symbol_name;
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  else
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    InternalFree(symbol_name);
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  rest = ExtractTokenUpToDelimiter(rest, ") ", out_module);
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  if (rest[0] == '(') {
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    if (out_file) {
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      rest++;
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      rest = ExtractTokenUpToDelimiter(rest, ":", out_file);
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      char *extracted_line_number;
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      rest = ExtractTokenUpToDelimiter(rest, ")", &extracted_line_number);
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      if (line) *line = (uptr)internal_atoll(extracted_line_number);
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      InternalFree(extracted_line_number);
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    }
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  } else if (rest[0] == '+') {
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    rest += 2;
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    uptr offset = internal_atoll(rest);
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    if (start_address) *start_address = addr - offset;
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  }
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  InternalFree(trim);
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  return true;
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}
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AtosSymbolizer::AtosSymbolizer(const char *path, LowLevelAllocator *allocator)
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    : process_(new (*allocator) AtosSymbolizerProcess(path)) {}
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bool AtosSymbolizer::SymbolizePC(uptr addr, SymbolizedStack *stack) {
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  if (!process_) return false;
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  if (addr == 0) return false;
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  char command[32];
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  internal_snprintf(command, sizeof(command), "0x%zx\n", addr);
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  const char *buf = process_->SendCommand(command);
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  if (!buf) return false;
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  uptr line;
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  uptr start_address = AddressInfo::kUnknown;
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  if (!ParseCommandOutput(buf, addr, &stack->info.function, &stack->info.module,
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                          &stack->info.file, &line, &start_address)) {
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    Report("WARNING: atos failed to symbolize address \"0x%zx\"\n", addr);
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    return false;
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  }
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  stack->info.line = (int)line;
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  if (start_address == AddressInfo::kUnknown) {
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    // Fallback to dladdr() to get function start address if atos doesn't report
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    // it.
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    Dl_info info;
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    int result = dladdr((const void *)addr, &info);
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    if (result)
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      start_address = reinterpret_cast<uptr>(info.dli_saddr);
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  }
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  // Only assign to `function_offset` if we were able to get the function's
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  // start address and we got a sensible `start_address` (dladdr doesn't always
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  // ensure that `addr >= sym_addr`).
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  if (start_address != AddressInfo::kUnknown && addr >= start_address) {
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    stack->info.function_offset = addr - start_address;
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  }
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  return true;
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}
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bool AtosSymbolizer::SymbolizeData(uptr addr, DataInfo *info) {
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  if (!process_) return false;
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  char command[32];
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  internal_snprintf(command, sizeof(command), "0x%zx\n", addr);
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  const char *buf = process_->SendCommand(command);
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  if (!buf) return false;
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  if (!ParseCommandOutput(buf, addr, &info->name, &info->module, nullptr,
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                          nullptr, &info->start)) {
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    process_ = nullptr;
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    return false;
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  }
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  return true;
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}
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}  // namespace __sanitizer
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#endif  // SANITIZER_APPLE
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