command_line.cc | Explore in Territory

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif

#include "base/command_line.h"

#include <ostream>
#include <string_view>

#include "base/check_op.h"
#include "base/containers/contains.h"
#include "base/containers/span.h"
#include "base/debug/debugging_buildflags.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/notreached.h"
#include "base/numerics/checked_math.h"
#include "base/ranges/algorithm.h"
#include "base/strings/strcat.h"
#include "base/strings/string_split.h"
#include "base/strings/string_tokenizer.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_WIN)
#include <windows.h>

#include <shellapi.h>

#include "base/strings/string_util_win.h"
#endif  // BUILDFLAG(IS_WIN)

namespace base {

CommandLine* CommandLine::current_process_commandline_ = …;

namespace {

DuplicateSwitchHandler* g_duplicate_switch_handler = …;

constexpr CommandLine::CharType kSwitchTerminator[] = …);
constexpr CommandLine::CharType kSwitchValueSeparator[] = …);

// Since we use a lazy match, make sure that longer versions (like "--") are
// listed before shorter versions (like "-") of similar prefixes.
#if BUILDFLAG(IS_WIN)
// By putting slash last, we can control whether it is treaded as a switch
// value by changing the value of switch_prefix_count to be one less than
// the array size.
constexpr CommandLine::StringViewType kSwitchPrefixes[] = {L"--", L"-", L"/"};
#elif BUILDFLAG(IS_POSIX) || BUILDFLAG(IS_FUCHSIA)
// Unixes don't use slash as a switch.
constexpr CommandLine::StringViewType kSwitchPrefixes[] = …;
#endif
size_t switch_prefix_count = …;

#if BUILDFLAG(IS_WIN)
// Switch string that specifies the single argument to the command line.
// If present, everything after this switch is interpreted as a single
// argument regardless of whitespace, quotes, etc. Used for launches from the
// Windows shell, which may have arguments with unencoded quotes that could
// otherwise unexpectedly be split into multiple arguments
// (https://crbug.com/937179).
constexpr CommandLine::CharType kSingleArgument[] =
    FILE_PATH_LITERAL("single-argument");
#endif  // BUILDFLAG(IS_WIN)

size_t GetSwitchPrefixLength(CommandLine::StringViewType string) { … }

// Fills in |switch_string| and |switch_value| if |string| is a switch.
// This will preserve the input switch prefix in the output |switch_string|.
bool IsSwitch(const CommandLine::StringType& string,
              CommandLine::StringType* switch_string,
              CommandLine::StringType* switch_value) { … }

// Returns true iff |string| represents a switch with key
// |switch_key_without_prefix|, regardless of value.
bool IsSwitchWithKey(CommandLine::StringViewType string,
                     CommandLine::StringViewType switch_key_without_prefix) { … }

#if BUILDFLAG(IS_WIN)
// Quotes a string as necessary for CommandLineToArgvW compatibility *on
// Windows*.
// http://msdn.microsoft.com/en-us/library/17w5ykft.aspx#parsing-c-command-line-arguments.
std::wstring QuoteForCommandLineToArgvWInternal(
    const std::wstring& arg,
    bool allow_unsafe_insert_sequences) {
  // Ensures that GetCommandLineString isn't used to generate command-line
  // strings for the Windows shell by checking for Windows insert sequences like
  // "%1". GetCommandLineStringForShell should be used instead to get a string
  // with the correct placeholder format for the shell.
  DCHECK(arg.size() != 2 || arg[0] != L'%' || allow_unsafe_insert_sequences);

  constexpr wchar_t kQuotableCharacters[] = L" \t\\\"";
  if (arg.find_first_of(kQuotableCharacters) == std::wstring::npos) {
    return arg;
  }

  std::wstring out(1, L'"');
  for (size_t i = 0; i < arg.size(); ++i) {
    if (arg[i] == L'\\') {
      // Finds the extent of this run of backslashes.
      size_t end = i + 1;
      while (end < arg.size() && arg[end] == L'\\') {
        ++end;
      }

      const size_t backslash_count = end - i;

      // Backslashes are escaped only if the run is followed by a double quote.
      // Since we also will end the string with a double quote, we escape for
      // either a double quote or the end of the string.
      const size_t backslash_multiplier =
          (end == arg.size() || arg[end] == L'"') ? 2 : 1;

      out.append(std::wstring(backslash_count * backslash_multiplier, L'\\'));

      // Advances `i` to one before `end` to balance `++i` in loop.
      i = end - 1;
    } else if (arg[i] == L'"') {
      out.append(LR"(\")");
    } else {
      out.push_back(arg[i]);
    }
  }

  out.push_back(L'"');

  return out;
}
#endif  // BUILDFLAG(IS_WIN)

}  // namespace

// static
void CommandLine::SetDuplicateSwitchHandler(
    std::unique_ptr<DuplicateSwitchHandler> new_duplicate_switch_handler) { … }

CommandLine::CommandLine(NoProgram no_program) : … { … }

CommandLine::CommandLine(const FilePath& program)
    : … { … }

CommandLine::CommandLine(int argc, const CommandLine::CharType* const* argv)
    : … { … }

CommandLine::CommandLine(const StringVector& argv)
    : … { … }

CommandLine::CommandLine(const CommandLine& other) = default;
CommandLine::CommandLine(CommandLine&& other) noexcept
    : … { … }
CommandLine& CommandLine::operator=(const CommandLine& other) = default;
CommandLine& CommandLine::operator=(CommandLine&& other) noexcept { … }
CommandLine::~CommandLine() = default;

#if BUILDFLAG(IS_WIN)
// static
void CommandLine::set_slash_is_not_a_switch() {
  // The last switch prefix should be slash, so adjust the size to skip it.
  static_assert(base::make_span(kSwitchPrefixes).back() == L"/",
                "Error: Last switch prefix is not a slash.");
  switch_prefix_count = std::size(kSwitchPrefixes) - 1;
}

// static
void CommandLine::InitUsingArgvForTesting(int argc, const char* const* argv) {
  DCHECK(!current_process_commandline_);
  current_process_commandline_ = new CommandLine(NO_PROGRAM);
  // On Windows we need to convert the command line arguments to std::wstring.
  CommandLine::StringVector argv_vector;
  for (int i = 0; i < argc; ++i)
    argv_vector.push_back(UTF8ToWide(argv[i]));
  current_process_commandline_->InitFromArgv(argv_vector);
}
#endif  // BUILDFLAG(IS_WIN)

// static
bool CommandLine::Init(int argc, const char* const* argv) { … }

// static
void CommandLine::Reset() { … }

// static
CommandLine* CommandLine::ForCurrentProcess() { … }

// static
bool CommandLine::InitializedForCurrentProcess() { … }

// static
CommandLine CommandLine::FromArgvWithoutProgram(const StringVector& argv) { … }

#if BUILDFLAG(IS_WIN)
// static
CommandLine CommandLine::FromString(StringViewType command_line) {
  CommandLine cmd(NO_PROGRAM);
  cmd.ParseFromString(command_line);
  return cmd;
}
#endif  // BUILDFLAG(IS_WIN)

void CommandLine::InitFromArgv(int argc,
                               const CommandLine::CharType* const* argv) { … }

void CommandLine::InitFromArgv(const StringVector& argv) { … }

FilePath CommandLine::GetProgram() const { … }

void CommandLine::SetProgram(const FilePath& program) { … }

bool CommandLine::HasSwitch(std::string_view switch_string) const { … }

bool CommandLine::HasSwitch(const char switch_constant[]) const { … }

std::string CommandLine::GetSwitchValueASCII(
    std::string_view switch_string) const { … }

FilePath CommandLine::GetSwitchValuePath(std::string_view switch_string) const { … }

CommandLine::StringType CommandLine::GetSwitchValueNative(
    std::string_view switch_string) const { … }

void CommandLine::AppendSwitch(std::string_view switch_string) { … }

void CommandLine::AppendSwitchPath(std::string_view switch_string,
                                   const FilePath& path) { … }

void CommandLine::AppendSwitchNative(std::string_view switch_string,
                                     CommandLine::StringViewType value) { … }

void CommandLine::AppendSwitchASCII(std::string_view switch_string,
                                    std::string_view value_string) { … }

void CommandLine::RemoveSwitch(std::string_view switch_key_without_prefix) { … }

void CommandLine::CopySwitchesFrom(const CommandLine& source,
                                   span<const char* const> switches) { … }

CommandLine::StringVector CommandLine::GetArgs() const { … }

void CommandLine::AppendArg(std::string_view value) { … }

void CommandLine::AppendArgPath(const FilePath& path) { … }

void CommandLine::AppendArgNative(StringViewType value) { … }

void CommandLine::AppendArguments(const CommandLine& other,
                                  bool include_program) { … }

void CommandLine::PrependWrapper(StringViewType wrapper) { … }

#if BUILDFLAG(IS_WIN)
void CommandLine::ParseFromString(StringViewType command_line) {
  command_line = TrimWhitespace(command_line, TRIM_ALL);
  if (command_line.empty())
    return;
  raw_command_line_string_ = command_line;

  int num_args = 0;
  wchar_t** args = NULL;
  // When calling CommandLineToArgvW, use the apiset if available.
  // Doing so will bypass loading shell32.dll on Windows.
  HMODULE downlevel_shell32_dll =
      ::LoadLibraryEx(L"api-ms-win-downlevel-shell32-l1-1-0.dll", nullptr,
                      LOAD_LIBRARY_SEARCH_SYSTEM32);
  if (downlevel_shell32_dll) {
    auto command_line_to_argv_w_proc =
        reinterpret_cast<decltype(::CommandLineToArgvW)*>(
            ::GetProcAddress(downlevel_shell32_dll, "CommandLineToArgvW"));
    if (command_line_to_argv_w_proc)
      args = command_line_to_argv_w_proc(command_line.data(), &num_args);
  } else {
    // Since the apiset is not available, allow the delayload of shell32.dll
    // to take place.
    args = ::CommandLineToArgvW(command_line.data(), &num_args);
  }

  DPLOG_IF(FATAL, !args) << "CommandLineToArgvW failed on command line: "
                         << command_line;
  StringVector argv(args, args + num_args);
  InitFromArgv(argv);
  raw_command_line_string_ = StringViewType();
  LocalFree(args);

  if (downlevel_shell32_dll)
    ::FreeLibrary(downlevel_shell32_dll);
}

#endif  // BUILDFLAG(IS_WIN)

void CommandLine::AppendSwitchesAndArguments(span<const StringType> argv) { … }

CommandLine::StringType CommandLine::GetArgumentsStringInternal(
    bool allow_unsafe_insert_sequences) const { … }

CommandLine::StringType CommandLine::GetCommandLineString() const { … }

#if BUILDFLAG(IS_WIN)
// static
std::wstring CommandLine::QuoteForCommandLineToArgvW(const std::wstring& arg) {
  return QuoteForCommandLineToArgvWInternal(
      arg, /*allow_unsafe_insert_sequences=*/false);
}

// NOTE: this function is used to set Chrome's open command in the registry
// during update. Any change to the syntax must be compatible with the prior
// version (i.e., any new syntax must be understood by older browsers expecting
// the old syntax, and the new browser must still handle the old syntax), as
// old versions are likely to persist, e.g., immediately after background
// update, when parsing command lines for other channels, when uninstalling web
// applications installed using the old syntax, etc.
CommandLine::StringType CommandLine::GetCommandLineStringForShell() const {
  DCHECK(GetArgs().empty());
  StringType command_line_string = GetCommandLineString();
  return command_line_string + FILE_PATH_LITERAL(" ") +
         StringType(kSwitchPrefixes[0]) + kSingleArgument +
         FILE_PATH_LITERAL(" %1");
}

CommandLine::StringType
CommandLine::GetCommandLineStringWithUnsafeInsertSequences() const {
  StringType string(argv_[0]);
  string = QuoteForCommandLineToArgvWInternal(
      string,
      /*allow_unsafe_insert_sequences=*/true);
  StringType params(
      GetArgumentsStringInternal(/*allow_unsafe_insert_sequences=*/true));
  if (!params.empty()) {
    string.append(FILE_PATH_LITERAL(" "));
    string.append(params);
  }
  return string;
}
#endif  // BUILDFLAG(IS_WIN)

CommandLine::StringType CommandLine::GetArgumentsString() const { … }

#if BUILDFLAG(IS_WIN)
void CommandLine::ParseAsSingleArgument(
    const CommandLine::StringType& single_arg_switch) {
  DCHECK(!raw_command_line_string_.empty());

  // Remove any previously parsed arguments.
  argv_.resize(static_cast<size_t>(begin_args_));

  // Locate "--single-argument" in the process's raw command line. Results are
  // unpredictable if "--single-argument" appears as part of a previous
  // argument or switch.
  const size_t single_arg_switch_position =
      raw_command_line_string_.find(single_arg_switch);
  DCHECK_NE(single_arg_switch_position, StringType::npos);

  // Append the portion of the raw command line that starts one character past
  // "--single-argument" as the one and only argument, or return if no
  // argument is present.
  const size_t arg_position =
      single_arg_switch_position + single_arg_switch.length() + 1;
  if (arg_position >= raw_command_line_string_.length())
    return;
  has_single_argument_switch_ = true;
  const StringViewType arg = raw_command_line_string_.substr(arg_position);
  if (!arg.empty()) {
    AppendArgNative(arg);
  }
}
#endif  // BUILDFLAG(IS_WIN)

void CommandLine::DetachFromCurrentSequence() { … }

}  // namespace base
chromium/base/command_line.cc
