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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include "base/command_line.h"
6 
7 #include <algorithm>
8 #include <iterator>
9 #include <ostream>
10 #include <string_view>
11 
12 #include "base/files/file_path.h"
13 #include "base/logging.h"
14 #include "base/stl_util.h"
15 #include "base/strings/string_split.h"
16 #include "base/strings/string_tokenizer.h"
17 #include "base/strings/string_util.h"
18 #include "base/strings/utf_string_conversions.h"
19 #include "util/build_config.h"
20 
21 #if defined(OS_WIN)
22 #include <windows.h>
23 
24 #include <shellapi.h>
25 #endif
26 
27 namespace base {
28 
29 CommandLine* CommandLine::current_process_commandline_ = nullptr;
30 
31 namespace {
32 
33 const CommandLine::CharType kSwitchTerminator[] = FILE_PATH_LITERAL("--");
34 const CommandLine::CharType kSwitchValueSeparator[] = FILE_PATH_LITERAL("=");
35 
36 // Since we use a lazy match, make sure that longer versions (like "--") are
37 // listed before shorter versions (like "-") of similar prefixes.
38 #if defined(OS_WIN)
39 // By putting slash last, we can control whether it is treaded as a switch
40 // value by changing the value of switch_prefix_count to be one less than
41 // the array size.
42 const CommandLine::CharType* const kSwitchPrefixes[] = {u"--", u"-", u"/"};
43 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
44 // Unixes don't use slash as a switch.
45 const CommandLine::CharType* const kSwitchPrefixes[] = {"--", "-"};
46 #endif
47 size_t switch_prefix_count = std::size(kSwitchPrefixes);
48 
GetSwitchPrefixLength(const CommandLine::StringType & string)49 size_t GetSwitchPrefixLength(const CommandLine::StringType& string) {
50   for (size_t i = 0; i < switch_prefix_count; ++i) {
51     CommandLine::StringType prefix(kSwitchPrefixes[i]);
52     if (string.compare(0, prefix.length(), prefix) == 0)
53       return prefix.length();
54   }
55   return 0;
56 }
57 
58 // Fills in |switch_string| and |switch_value| if |string| is a switch.
59 // This will preserve the input switch prefix in the output |switch_string|.
IsSwitch(const CommandLine::StringType & string,CommandLine::StringType * switch_string,CommandLine::StringType * switch_value)60 bool IsSwitch(const CommandLine::StringType& string,
61               CommandLine::StringType* switch_string,
62               CommandLine::StringType* switch_value) {
63   switch_string->clear();
64   switch_value->clear();
65   size_t prefix_length = GetSwitchPrefixLength(string);
66   if (prefix_length == 0 || prefix_length == string.length())
67     return false;
68 
69   const size_t equals_position = string.find(kSwitchValueSeparator);
70   *switch_string = string.substr(0, equals_position);
71   if (equals_position != CommandLine::StringType::npos)
72     *switch_value = string.substr(equals_position + 1);
73   return true;
74 }
75 
76 // Append switches and arguments, keeping switches before arguments
77 // if handle_switches is true.
AppendSwitchesAndArguments(CommandLine * command_line,const CommandLine::StringVector & argv,bool handle_switches)78 void AppendSwitchesAndArguments(CommandLine* command_line,
79                                 const CommandLine::StringVector& argv,
80                                 bool handle_switches) {
81   bool parse_switches = handle_switches;
82   for (size_t i = 1; i < argv.size(); ++i) {
83     CommandLine::StringType arg = argv[i];
84 #if defined(OS_WIN)
85     TrimWhitespace(arg, TRIM_ALL, &arg);
86 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
87     TrimWhitespaceASCII(arg, TRIM_ALL, &arg);
88 #endif
89 
90     CommandLine::StringType switch_string;
91     CommandLine::StringType switch_value;
92     parse_switches &= (arg != kSwitchTerminator);
93     if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
94 #if defined(OS_WIN)
95       command_line->AppendSwitchNative(UTF16ToASCII(switch_string),
96                                        switch_value);
97 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
98       command_line->AppendSwitchNative(switch_string, switch_value);
99 #else
100 #error Unsupported platform
101 #endif
102     } else {
103       command_line->AppendArgNative(arg);
104     }
105   }
106 }
107 
108 #if defined(OS_WIN)
109 // Quote a string as necessary for CommandLineToArgvW compatibility *on
110 // Windows*.
QuoteForCommandLineToArgvW(const std::u16string & arg,bool quote_placeholders)111 std::u16string QuoteForCommandLineToArgvW(const std::u16string& arg,
112                                           bool quote_placeholders) {
113   // We follow the quoting rules of CommandLineToArgvW.
114   // http://msdn.microsoft.com/en-us/library/17w5ykft.aspx
115   std::u16string quotable_chars(u" \\\"");
116   // We may also be required to quote '%', which is commonly used in a command
117   // line as a placeholder. (It may be substituted for a string with spaces.)
118   if (quote_placeholders)
119     quotable_chars.push_back('%');
120   if (arg.find_first_of(quotable_chars) == std::u16string::npos) {
121     // No quoting necessary.
122     return arg;
123   }
124 
125   std::u16string out;
126   out.push_back('"');
127   for (size_t i = 0; i < arg.size(); ++i) {
128     if (arg[i] == '\\') {
129       // Find the extent of this run of backslashes.
130       size_t start = i, end = start + 1;
131       for (; end < arg.size() && arg[end] == '\\'; ++end) {
132       }
133       size_t backslash_count = end - start;
134 
135       // Backslashes are escapes only if the run is followed by a double quote.
136       // Since we also will end the string with a double quote, we escape for
137       // either a double quote or the end of the string.
138       if (end == arg.size() || arg[end] == '"') {
139         // To quote, we need to output 2x as many backslashes.
140         backslash_count *= 2;
141       }
142       for (size_t j = 0; j < backslash_count; ++j)
143         out.push_back('\\');
144 
145       // Advance i to one before the end to balance i++ in loop.
146       i = end - 1;
147     } else if (arg[i] == '"') {
148       out.push_back('\\');
149       out.push_back('"');
150     } else {
151       out.push_back(arg[i]);
152     }
153   }
154   out.push_back('"');
155 
156   return out;
157 }
158 #endif
159 
160 }  // namespace
161 
CommandLine(NoProgram no_program)162 CommandLine::CommandLine(NoProgram no_program)
163     : argv_(1), begin_args_(1), parse_switches_(true) {}
164 
CommandLine(const FilePath & program)165 CommandLine::CommandLine(const FilePath& program)
166     : argv_(1), begin_args_(1), parse_switches_(true) {
167   SetProgram(program);
168 }
169 
CommandLine(int argc,const CommandLine::CharType * const * argv)170 CommandLine::CommandLine(int argc, const CommandLine::CharType* const* argv)
171     : argv_(1), begin_args_(1), parse_switches_(true) {
172   InitFromArgv(argc, argv);
173 }
174 
CommandLine(const StringVector & argv)175 CommandLine::CommandLine(const StringVector& argv)
176     : argv_(1), begin_args_(1), parse_switches_(true) {
177   InitFromArgv(argv);
178 }
179 
180 CommandLine::CommandLine(const CommandLine& other) = default;
181 
182 CommandLine& CommandLine::operator=(const CommandLine& other) = default;
183 
184 CommandLine::~CommandLine() = default;
185 
186 #if defined(OS_WIN)
187 // static
set_slash_is_not_a_switch()188 void CommandLine::set_slash_is_not_a_switch() {
189   // The last switch prefix should be slash, so adjust the size to skip it.
190   DCHECK(std::u16string_view(kSwitchPrefixes[std::size(kSwitchPrefixes) - 1]) ==
191          std::u16string_view(u"/"));
192   switch_prefix_count = std::size(kSwitchPrefixes) - 1;
193 }
194 
195 // static
InitUsingArgvForTesting(int argc,const char * const * argv)196 void CommandLine::InitUsingArgvForTesting(int argc, const char* const* argv) {
197   DCHECK(!current_process_commandline_);
198   current_process_commandline_ = new CommandLine(NO_PROGRAM);
199   // On Windows we need to convert the command line arguments to std::u16string.
200   base::CommandLine::StringVector argv_vector;
201   for (int i = 0; i < argc; ++i)
202     argv_vector.push_back(UTF8ToUTF16(argv[i]));
203   current_process_commandline_->InitFromArgv(argv_vector);
204 }
205 #endif
206 
207 // static
Init(int argc,const char * const * argv)208 bool CommandLine::Init(int argc, const char* const* argv) {
209   if (current_process_commandline_) {
210     // If this is intentional, Reset() must be called first. If we are using
211     // the shared build mode, we have to share a single object across multiple
212     // shared libraries.
213     return false;
214   }
215 
216   current_process_commandline_ = new CommandLine(NO_PROGRAM);
217 #if defined(OS_WIN)
218   current_process_commandline_->ParseFromString(
219       reinterpret_cast<const char16_t*>(::GetCommandLineW()));
220 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
221   current_process_commandline_->InitFromArgv(argc, argv);
222 #else
223 #error Unsupported platform
224 #endif
225 
226   return true;
227 }
228 
229 // static
Reset()230 void CommandLine::Reset() {
231   DCHECK(current_process_commandline_);
232   delete current_process_commandline_;
233   current_process_commandline_ = nullptr;
234 }
235 
236 // static
ForCurrentProcess()237 CommandLine* CommandLine::ForCurrentProcess() {
238   DCHECK(current_process_commandline_);
239   return current_process_commandline_;
240 }
241 
242 // static
InitializedForCurrentProcess()243 bool CommandLine::InitializedForCurrentProcess() {
244   return !!current_process_commandline_;
245 }
246 
247 #if defined(OS_WIN)
248 // static
FromString(const std::u16string & command_line)249 CommandLine CommandLine::FromString(const std::u16string& command_line) {
250   CommandLine cmd(NO_PROGRAM);
251   cmd.ParseFromString(command_line);
252   return cmd;
253 }
254 #endif
255 
InitFromArgv(int argc,const CommandLine::CharType * const * argv)256 void CommandLine::InitFromArgv(int argc,
257                                const CommandLine::CharType* const* argv) {
258   StringVector new_argv;
259   for (int i = 0; i < argc; ++i)
260     new_argv.push_back(argv[i]);
261   InitFromArgv(new_argv);
262 }
263 
InitFromArgv(const StringVector & argv)264 void CommandLine::InitFromArgv(const StringVector& argv) {
265   argv_ = StringVector(1);
266   switches_.clear();
267   begin_args_ = 1;
268   SetProgram(argv.empty() ? FilePath() : FilePath(argv[0]));
269   AppendSwitchesAndArguments(this, argv, parse_switches_);
270 }
271 
GetProgram() const272 FilePath CommandLine::GetProgram() const {
273   return FilePath(argv_[0]);
274 }
275 
SetProgram(const FilePath & program)276 void CommandLine::SetProgram(const FilePath& program) {
277 #if defined(OS_WIN)
278   TrimWhitespace(program.value(), TRIM_ALL, &argv_[0]);
279 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
280   TrimWhitespaceASCII(program.value(), TRIM_ALL, &argv_[0]);
281 #else
282 #error Unsupported platform
283 #endif
284 }
285 
HasSwitch(std::string_view switch_string) const286 bool CommandLine::HasSwitch(std::string_view switch_string) const {
287   DCHECK_EQ(ToLowerASCII(switch_string), switch_string);
288   return ContainsKey(switches_, switch_string);
289 }
290 
HasSwitch(const char switch_constant[]) const291 bool CommandLine::HasSwitch(const char switch_constant[]) const {
292   return HasSwitch(std::string_view(switch_constant));
293 }
294 
GetSwitchValueASCII(std::string_view switch_string) const295 std::string CommandLine::GetSwitchValueASCII(
296     std::string_view switch_string) const {
297   StringType value = GetSwitchValueNative(switch_string);
298   if (!IsStringASCII(value)) {
299     DLOG(WARNING) << "Value of switch (" << switch_string << ") must be ASCII.";
300     return std::string();
301   }
302 #if defined(OS_WIN)
303   return UTF16ToASCII(value);
304 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
305   return value;
306 #endif
307 }
308 
GetSwitchValuePath(std::string_view switch_string) const309 FilePath CommandLine::GetSwitchValuePath(std::string_view switch_string) const {
310   return FilePath(GetSwitchValueNative(switch_string));
311 }
312 
GetSwitchValueNative(std::string_view switch_string) const313 CommandLine::StringType CommandLine::GetSwitchValueNative(
314     std::string_view switch_string) const {
315   DCHECK_EQ(ToLowerASCII(switch_string), switch_string);
316   auto result = switches_.find(switch_string);
317   return result == switches_.end() ? StringType() : result->second;
318 }
319 
AppendSwitch(const std::string & switch_string)320 void CommandLine::AppendSwitch(const std::string& switch_string) {
321   AppendSwitchNative(switch_string, StringType());
322 }
323 
AppendSwitchPath(const std::string & switch_string,const FilePath & path)324 void CommandLine::AppendSwitchPath(const std::string& switch_string,
325                                    const FilePath& path) {
326   AppendSwitchNative(switch_string, path.value());
327 }
328 
AppendSwitchNative(const std::string & switch_string,const CommandLine::StringType & value)329 void CommandLine::AppendSwitchNative(const std::string& switch_string,
330                                      const CommandLine::StringType& value) {
331 #if defined(OS_WIN)
332   const std::string switch_key = ToLowerASCII(switch_string);
333   StringType combined_switch_string(ASCIIToUTF16(switch_key));
334 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
335   const std::string& switch_key = switch_string;
336   StringType combined_switch_string(switch_key);
337 #endif
338   size_t prefix_length = GetSwitchPrefixLength(combined_switch_string);
339   auto insertion =
340       switches_.insert(make_pair(switch_key.substr(prefix_length), value));
341   if (!insertion.second)
342     insertion.first->second = value;
343   // Preserve existing switch prefixes in |argv_|; only append one if necessary.
344   if (prefix_length == 0)
345     combined_switch_string = kSwitchPrefixes[0] + combined_switch_string;
346   if (!value.empty())
347     combined_switch_string += kSwitchValueSeparator + value;
348   // Append the switch and update the switches/arguments divider |begin_args_|.
349   argv_.insert(argv_.begin() + begin_args_++, combined_switch_string);
350 }
351 
AppendSwitchASCII(const std::string & switch_string,const std::string & value_string)352 void CommandLine::AppendSwitchASCII(const std::string& switch_string,
353                                     const std::string& value_string) {
354 #if defined(OS_WIN)
355   AppendSwitchNative(switch_string, ASCIIToUTF16(value_string));
356 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
357   AppendSwitchNative(switch_string, value_string);
358 #else
359 #error Unsupported platform
360 #endif
361 }
362 
CopySwitchesFrom(const CommandLine & source,const char * const switches[],size_t count)363 void CommandLine::CopySwitchesFrom(const CommandLine& source,
364                                    const char* const switches[],
365                                    size_t count) {
366   for (size_t i = 0; i < count; ++i) {
367     if (source.HasSwitch(switches[i]))
368       AppendSwitchNative(switches[i], source.GetSwitchValueNative(switches[i]));
369   }
370 }
371 
GetArgs() const372 CommandLine::StringVector CommandLine::GetArgs() const {
373   // Gather all arguments after the last switch (may include kSwitchTerminator).
374   StringVector args(argv_.begin() + begin_args_, argv_.end());
375   // Erase only the first kSwitchTerminator (maybe "--" is a legitimate page?)
376   StringVector::iterator switch_terminator =
377       std::find(args.begin(), args.end(), kSwitchTerminator);
378   if (switch_terminator != args.end())
379     args.erase(switch_terminator);
380   return args;
381 }
382 
AppendArg(const std::string & value)383 void CommandLine::AppendArg(const std::string& value) {
384 #if defined(OS_WIN)
385   DCHECK(IsStringUTF8(value));
386   AppendArgNative(UTF8ToUTF16(value));
387 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
388   AppendArgNative(value);
389 #else
390 #error Unsupported platform
391 #endif
392 }
393 
AppendArgPath(const FilePath & path)394 void CommandLine::AppendArgPath(const FilePath& path) {
395   AppendArgNative(path.value());
396 }
397 
AppendArgNative(const CommandLine::StringType & value)398 void CommandLine::AppendArgNative(const CommandLine::StringType& value) {
399   argv_.push_back(value);
400 }
401 
AppendArguments(const CommandLine & other,bool include_program)402 void CommandLine::AppendArguments(const CommandLine& other,
403                                   bool include_program) {
404   if (include_program)
405     SetProgram(other.GetProgram());
406   AppendSwitchesAndArguments(this, other.argv(), parse_switches_);
407 }
408 
PrependWrapper(const CommandLine::StringType & wrapper)409 void CommandLine::PrependWrapper(const CommandLine::StringType& wrapper) {
410   if (wrapper.empty())
411     return;
412   // Split the wrapper command based on whitespace (with quoting).
413   using CommandLineTokenizer =
414       StringTokenizerT<StringType, StringType::const_iterator>;
415   CommandLineTokenizer tokenizer(wrapper, FILE_PATH_LITERAL(" "));
416   tokenizer.set_quote_chars(FILE_PATH_LITERAL("'\""));
417   std::vector<StringType> wrapper_argv;
418   while (tokenizer.GetNext())
419     wrapper_argv.emplace_back(tokenizer.token());
420 
421   // Prepend the wrapper and update the switches/arguments |begin_args_|.
422   argv_.insert(argv_.begin(), wrapper_argv.begin(), wrapper_argv.end());
423   begin_args_ += wrapper_argv.size();
424 }
425 
426 #if defined(OS_WIN)
ParseFromString(const std::u16string & command_line)427 void CommandLine::ParseFromString(const std::u16string& command_line) {
428   std::u16string command_line_string;
429   TrimWhitespace(command_line, TRIM_ALL, &command_line_string);
430   if (command_line_string.empty())
431     return;
432 
433   int num_args = 0;
434   char16_t** args = NULL;
435   args = reinterpret_cast<char16_t**>(::CommandLineToArgvW(
436       reinterpret_cast<LPCWSTR>(command_line_string.c_str()), &num_args));
437 
438   DPLOG_IF(FATAL, !args) << "CommandLineToArgvW failed on command line: "
439                          << UTF16ToUTF8(command_line);
440   InitFromArgv(num_args, args);
441   LocalFree(args);
442 }
443 #endif
444 
GetCommandLineStringInternal(bool quote_placeholders) const445 CommandLine::StringType CommandLine::GetCommandLineStringInternal(
446     bool quote_placeholders) const {
447   StringType string(argv_[0]);
448 #if defined(OS_WIN)
449   string = QuoteForCommandLineToArgvW(string, quote_placeholders);
450 #endif
451   StringType params(GetArgumentsStringInternal(quote_placeholders));
452   if (!params.empty()) {
453     string.append(StringType(FILE_PATH_LITERAL(" ")));
454     string.append(params);
455   }
456   return string;
457 }
458 
GetArgumentsStringInternal(bool quote_placeholders) const459 CommandLine::StringType CommandLine::GetArgumentsStringInternal(
460     bool quote_placeholders) const {
461   StringType params;
462   // Append switches and arguments.
463   bool parse_switches = parse_switches_;
464   for (size_t i = 1; i < argv_.size(); ++i) {
465     StringType arg = argv_[i];
466     StringType switch_string;
467     StringType switch_value;
468     parse_switches &= arg != kSwitchTerminator;
469     if (i > 1)
470       params.append(StringType(FILE_PATH_LITERAL(" ")));
471     if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
472       params.append(switch_string);
473       if (!switch_value.empty()) {
474 #if defined(OS_WIN)
475         switch_value =
476             QuoteForCommandLineToArgvW(switch_value, quote_placeholders);
477 #endif
478         params.append(kSwitchValueSeparator + switch_value);
479       }
480     } else {
481 #if defined(OS_WIN)
482       arg = QuoteForCommandLineToArgvW(arg, quote_placeholders);
483 #endif
484       params.append(arg);
485     }
486   }
487   return params;
488 }
489 
490 }  // namespace base
491