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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/macros.h"
15 #include "base/stl_util.h"
16 #include "base/strings/string_split.h"
17 #include "base/strings/string_tokenizer.h"
18 #include "base/strings/string_util.h"
19 #include "base/strings/utf_string_conversions.h"
20 #include "util/build_config.h"
21 
22 #if defined(OS_WIN)
23 #include <windows.h>
24 
25 #include <shellapi.h>
26 #endif
27 
28 namespace base {
29 
30 CommandLine* CommandLine::current_process_commandline_ = nullptr;
31 
32 namespace {
33 
34 const CommandLine::CharType kSwitchTerminator[] = FILE_PATH_LITERAL("--");
35 const CommandLine::CharType kSwitchValueSeparator[] = FILE_PATH_LITERAL("=");
36 
37 // Since we use a lazy match, make sure that longer versions (like "--") are
38 // listed before shorter versions (like "-") of similar prefixes.
39 #if defined(OS_WIN)
40 // By putting slash last, we can control whether it is treaded as a switch
41 // value by changing the value of switch_prefix_count to be one less than
42 // the array size.
43 const CommandLine::CharType* const kSwitchPrefixes[] = {u"--", u"-", u"/"};
44 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
45 // Unixes don't use slash as a switch.
46 const CommandLine::CharType* const kSwitchPrefixes[] = {"--", "-"};
47 #endif
48 size_t switch_prefix_count = std::size(kSwitchPrefixes);
49 
GetSwitchPrefixLength(const CommandLine::StringType & string)50 size_t GetSwitchPrefixLength(const CommandLine::StringType& string) {
51   for (size_t i = 0; i < switch_prefix_count; ++i) {
52     CommandLine::StringType prefix(kSwitchPrefixes[i]);
53     if (string.compare(0, prefix.length(), prefix) == 0)
54       return prefix.length();
55   }
56   return 0;
57 }
58 
59 // Fills in |switch_string| and |switch_value| if |string| is a switch.
60 // 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)61 bool IsSwitch(const CommandLine::StringType& string,
62               CommandLine::StringType* switch_string,
63               CommandLine::StringType* switch_value) {
64   switch_string->clear();
65   switch_value->clear();
66   size_t prefix_length = GetSwitchPrefixLength(string);
67   if (prefix_length == 0 || prefix_length == string.length())
68     return false;
69 
70   const size_t equals_position = string.find(kSwitchValueSeparator);
71   *switch_string = string.substr(0, equals_position);
72   if (equals_position != CommandLine::StringType::npos)
73     *switch_value = string.substr(equals_position + 1);
74   return true;
75 }
76 
77 // Append switches and arguments, keeping switches before arguments
78 // if handle_switches is true.
AppendSwitchesAndArguments(CommandLine * command_line,const CommandLine::StringVector & argv,bool handle_switches)79 void AppendSwitchesAndArguments(CommandLine* command_line,
80                                 const CommandLine::StringVector& argv,
81                                 bool handle_switches) {
82   bool parse_switches = handle_switches;
83   for (size_t i = 1; i < argv.size(); ++i) {
84     CommandLine::StringType arg = argv[i];
85 #if defined(OS_WIN)
86     TrimWhitespace(arg, TRIM_ALL, &arg);
87 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
88     TrimWhitespaceASCII(arg, TRIM_ALL, &arg);
89 #endif
90 
91     CommandLine::StringType switch_string;
92     CommandLine::StringType switch_value;
93     parse_switches &= (arg != kSwitchTerminator);
94     if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
95 #if defined(OS_WIN)
96       command_line->AppendSwitchNative(UTF16ToASCII(switch_string),
97                                        switch_value);
98 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
99       command_line->AppendSwitchNative(switch_string, switch_value);
100 #else
101 #error Unsupported platform
102 #endif
103     } else {
104       command_line->AppendArgNative(arg);
105     }
106   }
107 }
108 
109 #if defined(OS_WIN)
110 // Quote a string as necessary for CommandLineToArgvW compatiblity *on 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(const std::string_view & switch_string) const286 bool CommandLine::HasSwitch(const 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(const std::string_view & switch_string) const295 std::string CommandLine::GetSwitchValueASCII(
296     const 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(const std::string_view & switch_string) const309 FilePath CommandLine::GetSwitchValuePath(
310     const std::string_view& switch_string) const {
311   return FilePath(GetSwitchValueNative(switch_string));
312 }
313 
GetSwitchValueNative(const std::string_view & switch_string) const314 CommandLine::StringType CommandLine::GetSwitchValueNative(
315     const std::string_view& switch_string) const {
316   DCHECK_EQ(ToLowerASCII(switch_string), switch_string);
317   auto result = switches_.find(switch_string);
318   return result == switches_.end() ? StringType() : result->second;
319 }
320 
AppendSwitch(const std::string & switch_string)321 void CommandLine::AppendSwitch(const std::string& switch_string) {
322   AppendSwitchNative(switch_string, StringType());
323 }
324 
AppendSwitchPath(const std::string & switch_string,const FilePath & path)325 void CommandLine::AppendSwitchPath(const std::string& switch_string,
326                                    const FilePath& path) {
327   AppendSwitchNative(switch_string, path.value());
328 }
329 
AppendSwitchNative(const std::string & switch_string,const CommandLine::StringType & value)330 void CommandLine::AppendSwitchNative(const std::string& switch_string,
331                                      const CommandLine::StringType& value) {
332 #if defined(OS_WIN)
333   const std::string switch_key = ToLowerASCII(switch_string);
334   StringType combined_switch_string(ASCIIToUTF16(switch_key));
335 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
336   const std::string& switch_key = switch_string;
337   StringType combined_switch_string(switch_key);
338 #endif
339   size_t prefix_length = GetSwitchPrefixLength(combined_switch_string);
340   auto insertion =
341       switches_.insert(make_pair(switch_key.substr(prefix_length), value));
342   if (!insertion.second)
343     insertion.first->second = value;
344   // Preserve existing switch prefixes in |argv_|; only append one if necessary.
345   if (prefix_length == 0)
346     combined_switch_string = kSwitchPrefixes[0] + combined_switch_string;
347   if (!value.empty())
348     combined_switch_string += kSwitchValueSeparator + value;
349   // Append the switch and update the switches/arguments divider |begin_args_|.
350   argv_.insert(argv_.begin() + begin_args_++, combined_switch_string);
351 }
352 
AppendSwitchASCII(const std::string & switch_string,const std::string & value_string)353 void CommandLine::AppendSwitchASCII(const std::string& switch_string,
354                                     const std::string& value_string) {
355 #if defined(OS_WIN)
356   AppendSwitchNative(switch_string, ASCIIToUTF16(value_string));
357 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
358   AppendSwitchNative(switch_string, value_string);
359 #else
360 #error Unsupported platform
361 #endif
362 }
363 
CopySwitchesFrom(const CommandLine & source,const char * const switches[],size_t count)364 void CommandLine::CopySwitchesFrom(const CommandLine& source,
365                                    const char* const switches[],
366                                    size_t count) {
367   for (size_t i = 0; i < count; ++i) {
368     if (source.HasSwitch(switches[i]))
369       AppendSwitchNative(switches[i], source.GetSwitchValueNative(switches[i]));
370   }
371 }
372 
GetArgs() const373 CommandLine::StringVector CommandLine::GetArgs() const {
374   // Gather all arguments after the last switch (may include kSwitchTerminator).
375   StringVector args(argv_.begin() + begin_args_, argv_.end());
376   // Erase only the first kSwitchTerminator (maybe "--" is a legitimate page?)
377   StringVector::iterator switch_terminator =
378       std::find(args.begin(), args.end(), kSwitchTerminator);
379   if (switch_terminator != args.end())
380     args.erase(switch_terminator);
381   return args;
382 }
383 
AppendArg(const std::string & value)384 void CommandLine::AppendArg(const std::string& value) {
385 #if defined(OS_WIN)
386   DCHECK(IsStringUTF8(value));
387   AppendArgNative(UTF8ToUTF16(value));
388 #elif defined(OS_POSIX) || defined(OS_FUCHSIA)
389   AppendArgNative(value);
390 #else
391 #error Unsupported platform
392 #endif
393 }
394 
AppendArgPath(const FilePath & path)395 void CommandLine::AppendArgPath(const FilePath& path) {
396   AppendArgNative(path.value());
397 }
398 
AppendArgNative(const CommandLine::StringType & value)399 void CommandLine::AppendArgNative(const CommandLine::StringType& value) {
400   argv_.push_back(value);
401 }
402 
AppendArguments(const CommandLine & other,bool include_program)403 void CommandLine::AppendArguments(const CommandLine& other,
404                                   bool include_program) {
405   if (include_program)
406     SetProgram(other.GetProgram());
407   AppendSwitchesAndArguments(this, other.argv(), parse_switches_);
408 }
409 
PrependWrapper(const CommandLine::StringType & wrapper)410 void CommandLine::PrependWrapper(const CommandLine::StringType& wrapper) {
411   if (wrapper.empty())
412     return;
413   // Split the wrapper command based on whitespace (with quoting).
414   using CommandLineTokenizer =
415       StringTokenizerT<StringType, StringType::const_iterator>;
416   CommandLineTokenizer tokenizer(wrapper, FILE_PATH_LITERAL(" "));
417   tokenizer.set_quote_chars(FILE_PATH_LITERAL("'\""));
418   std::vector<StringType> wrapper_argv;
419   while (tokenizer.GetNext())
420     wrapper_argv.emplace_back(tokenizer.token());
421 
422   // Prepend the wrapper and update the switches/arguments |begin_args_|.
423   argv_.insert(argv_.begin(), wrapper_argv.begin(), wrapper_argv.end());
424   begin_args_ += wrapper_argv.size();
425 }
426 
427 #if defined(OS_WIN)
ParseFromString(const std::u16string & command_line)428 void CommandLine::ParseFromString(const std::u16string& command_line) {
429   std::u16string command_line_string;
430   TrimWhitespace(command_line, TRIM_ALL, &command_line_string);
431   if (command_line_string.empty())
432     return;
433 
434   int num_args = 0;
435   char16_t** args = NULL;
436   args = reinterpret_cast<char16_t**>(::CommandLineToArgvW(
437       reinterpret_cast<LPCWSTR>(command_line_string.c_str()), &num_args));
438 
439   DPLOG_IF(FATAL, !args) << "CommandLineToArgvW failed on command line: "
440                          << UTF16ToUTF8(command_line);
441   InitFromArgv(num_args, args);
442   LocalFree(args);
443 }
444 #endif
445 
GetCommandLineStringInternal(bool quote_placeholders) const446 CommandLine::StringType CommandLine::GetCommandLineStringInternal(
447     bool quote_placeholders) const {
448   StringType string(argv_[0]);
449 #if defined(OS_WIN)
450   string = QuoteForCommandLineToArgvW(string, quote_placeholders);
451 #endif
452   StringType params(GetArgumentsStringInternal(quote_placeholders));
453   if (!params.empty()) {
454     string.append(StringType(FILE_PATH_LITERAL(" ")));
455     string.append(params);
456   }
457   return string;
458 }
459 
GetArgumentsStringInternal(bool quote_placeholders) const460 CommandLine::StringType CommandLine::GetArgumentsStringInternal(
461     bool quote_placeholders) const {
462   StringType params;
463   // Append switches and arguments.
464   bool parse_switches = parse_switches_;
465   for (size_t i = 1; i < argv_.size(); ++i) {
466     StringType arg = argv_[i];
467     StringType switch_string;
468     StringType switch_value;
469     parse_switches &= arg != kSwitchTerminator;
470     if (i > 1)
471       params.append(StringType(FILE_PATH_LITERAL(" ")));
472     if (parse_switches && IsSwitch(arg, &switch_string, &switch_value)) {
473       params.append(switch_string);
474       if (!switch_value.empty()) {
475 #if defined(OS_WIN)
476         switch_value =
477             QuoteForCommandLineToArgvW(switch_value, quote_placeholders);
478 #endif
479         params.append(kSwitchValueSeparator + switch_value);
480       }
481     } else {
482 #if defined(OS_WIN)
483       arg = QuoteForCommandLineToArgvW(arg, quote_placeholders);
484 #endif
485       params.append(arg);
486     }
487   }
488   return params;
489 }
490 
491 }  // namespace base
492