lldb/source/Utility/Args.cpp

   1 //===-- Args.cpp ----------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "lldb/Utility/Args.h"
  10 #include "lldb/Utility/FileSpec.h"
  11 #include "lldb/Utility/Stream.h"
  12 #include "lldb/Utility/StringList.h"
  13 #include "llvm/ADT/StringSwitch.h"
  14
  15 using namespace lldb;
  16 using namespace lldb_private;
  17
  18 // A helper function for argument parsing.
  19 // Parses the initial part of the first argument using normal double quote
  20 // rules: backslash escapes the double quote and itself. The parsed string is
  21 // appended to the second argument. The function returns the unparsed portion
  22 // of the string, starting at the closing quote.
  23 static llvm::StringRef ParseDoubleQuotes(llvm::StringRef quoted,
  24                                          std::string &result) {
  25   // Inside double quotes, '\' and '"' are special.
  26   static const char *k_escapable_characters = "\"\\";
  27   while (true) {
  28     // Skip over regular characters and append them.
  29     size_t regular = quoted.find_first_of(k_escapable_characters);
  30     result += quoted.substr(0, regular);
  31     quoted = quoted.substr(regular);
  32
  33     // If we have reached the end of string or the closing quote, we're done.
  34     if (quoted.empty() || quoted.front() == '"')
  35       break;
  36
  37     // We have found a backslash.
  38     quoted = quoted.drop_front();
  39
  40     if (quoted.empty()) {
  41       // A lone backslash at the end of string, let's just append it.
  42       result += '\\';
  43       break;
  44     }
  45
  46     // If the character after the backslash is not an allowed escapable
  47     // character, we leave the character sequence untouched.
  48     if (strchr(k_escapable_characters, quoted.front()) == nullptr)
  49       result += '\\';
  50
  51     result += quoted.front();
  52     quoted = quoted.drop_front();
  53   }
  54
  55   return quoted;
  56 }
  57
  58 static size_t ArgvToArgc(const char **argv) {
  59   if (!argv)
  60     return 0;
  61   size_t count = 0;
  62   while (*argv++)
  63     ++count;
  64   return count;
  65 }
  66
  67 // Trims all whitespace that can separate command line arguments from the left
  68 // side of the string.
  69 static llvm::StringRef ltrimForArgs(llvm::StringRef str, size_t &shift) {
  70   static const char *k_space_separators = " \t";
  71   llvm::StringRef result = str.ltrim(k_space_separators);
  72   shift = result.data() - str.data();
  73   return result;
  74 }
  75
  76 // A helper function for SetCommandString. Parses a single argument from the
  77 // command string, processing quotes and backslashes in a shell-like manner.
  78 // The function returns a tuple consisting of the parsed argument, the quote
  79 // char used, and the unparsed portion of the string starting at the first
  80 // unqouted, unescaped whitespace character.
  81 static std::tuple<std::string, char, llvm::StringRef>
  82 ParseSingleArgument(llvm::StringRef command) {
  83   // Argument can be split into multiple discontiguous pieces, for example:
  84   //  "Hello ""World"
  85   // this would result in a single argument "Hello World" (without the quotes)
  86   // since the quotes would be removed and there is not space between the
  87   // strings.
  88   std::string arg;
  89
  90   // Since we can have multiple quotes that form a single command in a command
  91   // like: "Hello "world'!' (which will make a single argument "Hello world!")
  92   // we remember the first quote character we encounter and use that for the
  93   // quote character.
  94   char first_quote_char = '\0';
  95
  96   bool arg_complete = false;
  97   do {
  98     // Skip over regular characters and append them.
  99     size_t regular = command.find_first_of(" \t\r\"'`\\");
 100     arg += command.substr(0, regular);
 101     command = command.substr(regular);
 102
 103     if (command.empty())
 104       break;
 105
 106     char special = command.front();
 107     command = command.drop_front();
 108     switch (special) {
 109     case '\\':
 110       if (command.empty()) {
 111         arg += '\\';
 112         break;
 113       }
 114
 115       // If the character after the backslash is not an allowed escapable
 116       // character, we leave the character sequence untouched.
 117       if (strchr(" \t\\'\"`", command.front()) == nullptr)
 118         arg += '\\';
 119
 120       arg += command.front();
 121       command = command.drop_front();
 122
 123       break;
 124
 125     case ' ':
 126     case '\t':
 127     case '\r':
 128       // We are not inside any quotes, we just found a space after an argument.
 129       // We are done.
 130       arg_complete = true;
 131       break;
 132
 133     case '"':
 134     case '\'':
 135     case '`':
 136       // We found the start of a quote scope.
 137       if (first_quote_char == '\0')
 138         first_quote_char = special;
 139
 140       if (special == '"')
 141         command = ParseDoubleQuotes(command, arg);
 142       else {
 143         // For single quotes, we simply skip ahead to the matching quote
 144         // character (or the end of the string).
 145         size_t quoted = command.find(special);
 146         arg += command.substr(0, quoted);
 147         command = command.substr(quoted);
 148       }
 149
 150       // If we found a closing quote, skip it.
 151       if (!command.empty())
 152         command = command.drop_front();
 153
 154       break;
 155     }
 156   } while (!arg_complete);
 157
 158   return std::make_tuple(arg, first_quote_char, command);
 159 }
 160
 161 Args::ArgEntry::ArgEntry(llvm::StringRef str, char quote,
 162                          std::optional<uint16_t> column)
 163     : quote(quote), column(column) {
 164   size_t size = str.size();
 165   ptr.reset(new char[size + 1]);
 166
 167   ::memcpy(data(), str.data() ? str.data() : "", size);
 168   ptr[size] = 0;
 169 }
 170
 171 // Args constructor
 172 Args::Args(llvm::StringRef command) { SetCommandString(command); }
 173
 174 Args::Args(const Args &rhs) { *this = rhs; }
 175
 176 Args::Args(const StringList &list) : Args() {
 177   for (const std::string &arg : list)
 178     AppendArgument(arg);
 179 }
 180
 181 Args::Args(llvm::ArrayRef<llvm::StringRef> args) : Args() {
 182   for (llvm::StringRef arg : args)
 183     AppendArgument(arg);
 184 }
 185
 186 Args &Args::operator=(const Args &rhs) {
 187   Clear();
 188
 189   m_argv.clear();
 190   m_entries.clear();
 191   for (auto &entry : rhs.m_entries) {
 192     m_entries.emplace_back(entry.ref(), entry.quote, entry.column);
 193     m_argv.push_back(m_entries.back().data());
 194   }
 195   m_argv.push_back(nullptr);
 196   return *this;
 197 }
 198
 199 // Destructor
 200 Args::~Args() = default;
 201
 202 void Args::Dump(Stream &s, const char *label_name) const {
 203   if (!label_name)
 204     return;
 205
 206   int i = 0;
 207   for (auto &entry : m_entries) {
 208     s.Indent();
 209     s.Format("{0}[{1}]=\"{2}\"\n", label_name, i++, entry.ref());
 210   }
 211   s.Format("{0}[{1}]=NULL\n", label_name, i);
 212   s.EOL();
 213 }
 214
 215 bool Args::GetCommandString(std::string &command) const {
 216   command.clear();
 217
 218   for (size_t i = 0; i < m_entries.size(); ++i) {
 219     if (i > 0)
 220       command += ' ';
 221     char quote = m_entries[i].quote;
 222     if (quote != '\0')
 223      command += quote;
 224     command += m_entries[i].ref();
 225     if (quote != '\0')
 226       command += quote;
 227   }
 228
 229   return !m_entries.empty();
 230 }
 231
 232 bool Args::GetQuotedCommandString(std::string &command) const {
 233   command.clear();
 234
 235   for (size_t i = 0; i < m_entries.size(); ++i) {
 236     if (i > 0)
 237       command += ' ';
 238
 239     if (m_entries[i].quote) {
 240       command += m_entries[i].quote;
 241       command += m_entries[i].ref();
 242       command += m_entries[i].quote;
 243     } else {
 244       command += m_entries[i].ref();
 245     }
 246   }
 247
 248   return !m_entries.empty();
 249 }
 250
 251 void Args::SetCommandString(llvm::StringRef command) {
 252   Clear();
 253   m_argv.clear();
 254
 255   uint16_t column = 1;
 256   size_t shift = 0;
 257   command = ltrimForArgs(command, shift);
 258   column += shift;
 259   std::string arg;
 260   char quote;
 261   while (!command.empty()) {
 262     const char *prev = command.data();
 263     std::tie(arg, quote, command) = ParseSingleArgument(command);
 264     m_entries.emplace_back(arg, quote, column);
 265     m_argv.push_back(m_entries.back().data());
 266     command = ltrimForArgs(command, shift);
 267     column += shift;
 268     column += command.data() - prev;
 269   }
 270   m_argv.push_back(nullptr);
 271 }
 272
 273 const char *Args::GetArgumentAtIndex(size_t idx) const {
 274   if (idx < m_argv.size())
 275     return m_argv[idx];
 276   return nullptr;
 277 }
 278
 279 char **Args::GetArgumentVector() {
 280   assert(!m_argv.empty());
 281   // TODO: functions like execve and posix_spawnp exhibit undefined behavior
 282   // when argv or envp is null.  So the code below is actually wrong.  However,
 283   // other code in LLDB depends on it being null.  The code has been acting
 284   // this way for some time, so it makes sense to leave it this way until
 285   // someone has the time to come along and fix it.
 286   return (m_argv.size() > 1) ? m_argv.data() : nullptr;
 287 }
 288
 289 const char **Args::GetConstArgumentVector() const {
 290   assert(!m_argv.empty());
 291   return (m_argv.size() > 1) ? const_cast<const char **>(m_argv.data())
 292                              : nullptr;
 293 }
 294
 295 void Args::Shift() {
 296   // Don't pop the last NULL terminator from the argv array
 297   if (m_entries.empty())
 298     return;
 299   m_argv.erase(m_argv.begin());
 300   m_entries.erase(m_entries.begin());
 301 }
 302
 303 void Args::Unshift(llvm::StringRef arg_str, char quote_char) {
 304   InsertArgumentAtIndex(0, arg_str, quote_char);
 305 }
 306
 307 void Args::AppendArguments(const Args &rhs) {
 308   assert(m_argv.size() == m_entries.size() + 1);
 309   assert(m_argv.back() == nullptr);
 310   m_argv.pop_back();
 311   for (auto &entry : rhs.m_entries) {
 312     m_entries.emplace_back(entry.ref(), entry.quote, entry.column);
 313     m_argv.push_back(m_entries.back().data());
 314   }
 315   m_argv.push_back(nullptr);
 316 }
 317
 318 void Args::AppendArguments(const char **argv) {
 319   size_t argc = ArgvToArgc(argv);
 320
 321   assert(m_argv.size() == m_entries.size() + 1);
 322   assert(m_argv.back() == nullptr);
 323   m_argv.pop_back();
 324   for (auto arg : llvm::ArrayRef(argv, argc)) {
 325     m_entries.emplace_back(arg, '\0', std::nullopt);
 326     m_argv.push_back(m_entries.back().data());
 327   }
 328
 329   m_argv.push_back(nullptr);
 330 }
 331
 332 void Args::AppendArgument(llvm::StringRef arg_str, char quote_char) {
 333   InsertArgumentAtIndex(GetArgumentCount(), arg_str, quote_char);
 334 }
 335
 336 void Args::InsertArgumentAtIndex(size_t idx, llvm::StringRef arg_str,
 337                                  char quote_char) {
 338   assert(m_argv.size() == m_entries.size() + 1);
 339   assert(m_argv.back() == nullptr);
 340
 341   if (idx > m_entries.size())
 342     return;
 343   m_entries.emplace(m_entries.begin() + idx, arg_str, quote_char, std::nullopt);
 344   m_argv.insert(m_argv.begin() + idx, m_entries[idx].data());
 345 }
 346
 347 void Args::ReplaceArgumentAtIndex(size_t idx, llvm::StringRef arg_str,
 348                                   char quote_char) {
 349   assert(m_argv.size() == m_entries.size() + 1);
 350   assert(m_argv.back() == nullptr);
 351
 352   if (idx >= m_entries.size())
 353     return;
 354
 355   m_entries[idx] = ArgEntry(arg_str, quote_char, std::nullopt);
 356   m_argv[idx] = m_entries[idx].data();
 357 }
 358
 359 void Args::DeleteArgumentAtIndex(size_t idx) {
 360   if (idx >= m_entries.size())
 361     return;
 362
 363   m_argv.erase(m_argv.begin() + idx);
 364   m_entries.erase(m_entries.begin() + idx);
 365 }
 366
 367 void Args::SetArguments(size_t argc, const char **argv) {
 368   Clear();
 369
 370   auto args = llvm::ArrayRef(argv, argc);
 371   m_entries.resize(argc);
 372   m_argv.resize(argc + 1);
 373   for (size_t i = 0; i < args.size(); ++i) {
 374     char quote =
 375         ((args[i][0] == '\'') || (args[i][0] == '"') || (args[i][0] == '`'))
 376             ? args[i][0]
 377             : '\0';
 378
 379     m_entries[i] = ArgEntry(args[i], quote, std::nullopt);
 380     m_argv[i] = m_entries[i].data();
 381   }
 382 }
 383
 384 void Args::SetArguments(const char **argv) {
 385   SetArguments(ArgvToArgc(argv), argv);
 386 }
 387
 388 void Args::Clear() {
 389   m_entries.clear();
 390   m_argv.clear();
 391   m_argv.push_back(nullptr);
 392 }
 393
 394 std::string Args::GetShellSafeArgument(const FileSpec &shell,
 395                                        llvm::StringRef unsafe_arg) {
 396   struct ShellDescriptor {
 397     llvm::StringRef m_basename;
 398     llvm::StringRef m_escapables;
 399   };
 400
 401   static ShellDescriptor g_Shells[] = {{"bash", " '\"<>()&;"},
 402                                        {"fish", " '\"<>()&\\|;"},
 403                                        {"tcsh", " '\"<>()&;"},
 404                                        {"zsh", " '\"<>()&;\\|"},
 405                                        {"sh", " '\"<>()&;"}};
 406
 407   // safe minimal set
 408   llvm::StringRef escapables = " '\"";
 409
 410   auto basename = shell.GetFilename().GetStringRef();
 411   if (!basename.empty()) {
 412     for (const auto &Shell : g_Shells) {
 413       if (Shell.m_basename == basename) {
 414         escapables = Shell.m_escapables;
 415         break;
 416       }
 417     }
 418   }
 419
 420   std::string safe_arg;
 421   safe_arg.reserve(unsafe_arg.size());
 422   // Add a \ before every character that needs to be escaped.
 423   for (char c : unsafe_arg) {
 424     if (escapables.contains(c))
 425       safe_arg.push_back('\\');
 426     safe_arg.push_back(c);
 427   }
 428   return safe_arg;
 429 }
 430
 431 lldb::Encoding Args::StringToEncoding(llvm::StringRef s,
 432                                       lldb::Encoding fail_value) {
 433   return llvm::StringSwitch<lldb::Encoding>(s)
 434       .Case("uint", eEncodingUint)
 435       .Case("sint", eEncodingSint)
 436       .Case("ieee754", eEncodingIEEE754)
 437       .Case("vector", eEncodingVector)
 438       .Default(fail_value);
 439 }
 440
 441 uint32_t Args::StringToGenericRegister(llvm::StringRef s) {
 442   if (s.empty())
 443     return LLDB_INVALID_REGNUM;
 444   uint32_t result = llvm::StringSwitch<uint32_t>(s)
 445                         .Case("pc", LLDB_REGNUM_GENERIC_PC)
 446                         .Case("sp", LLDB_REGNUM_GENERIC_SP)
 447                         .Case("fp", LLDB_REGNUM_GENERIC_FP)
 448                         .Cases("ra", "lr", LLDB_REGNUM_GENERIC_RA)
 449                         .Case("flags", LLDB_REGNUM_GENERIC_FLAGS)
 450                         .Case("arg1", LLDB_REGNUM_GENERIC_ARG1)
 451                         .Case("arg2", LLDB_REGNUM_GENERIC_ARG2)
 452                         .Case("arg3", LLDB_REGNUM_GENERIC_ARG3)
 453                         .Case("arg4", LLDB_REGNUM_GENERIC_ARG4)
 454                         .Case("arg5", LLDB_REGNUM_GENERIC_ARG5)
 455                         .Case("arg6", LLDB_REGNUM_GENERIC_ARG6)
 456                         .Case("arg7", LLDB_REGNUM_GENERIC_ARG7)
 457                         .Case("arg8", LLDB_REGNUM_GENERIC_ARG8)
 458                         .Case("tp", LLDB_REGNUM_GENERIC_TP)
 459                         .Default(LLDB_INVALID_REGNUM);
 460   return result;
 461 }
 462
 463 void Args::EncodeEscapeSequences(const char *src, std::string &dst) {
 464   dst.clear();
 465   if (src) {
 466     for (const char *p = src; *p != '\0'; ++p) {
 467       size_t non_special_chars = ::strcspn(p, "\\");
 468       if (non_special_chars > 0) {
 469         dst.append(p, non_special_chars);
 470         p += non_special_chars;
 471         if (*p == '\0')
 472           break;
 473       }
 474
 475       if (*p == '\\') {
 476         ++p; // skip the slash
 477         switch (*p) {
 478         case 'a':
 479           dst.append(1, '\a');
 480           break;
 481         case 'b':
 482           dst.append(1, '\b');
 483           break;
 484         case 'f':
 485           dst.append(1, '\f');
 486           break;
 487         case 'n':
 488           dst.append(1, '\n');
 489           break;
 490         case 'r':
 491           dst.append(1, '\r');
 492           break;
 493         case 't':
 494           dst.append(1, '\t');
 495           break;
 496         case 'v':
 497           dst.append(1, '\v');
 498           break;
 499         case '\\':
 500           dst.append(1, '\\');
 501           break;
 502         case '\'':
 503           dst.append(1, '\'');
 504           break;
 505         case '"':
 506           dst.append(1, '"');
 507           break;
 508         case '0':
 509           // 1 to 3 octal chars
 510           {
 511             // Make a string that can hold onto the initial zero char, up to 3
 512             // octal digits, and a terminating NULL.
 513             char oct_str[5] = {'\0', '\0', '\0', '\0', '\0'};
 514
 515             int i;
 516             for (i = 0; (p[i] >= '0' && p[i] <= '7') && i < 4; ++i)
 517               oct_str[i] = p[i];
 518
 519             // We don't want to consume the last octal character since the main
 520             // for loop will do this for us, so we advance p by one less than i
 521             // (even if i is zero)
 522             p += i - 1;
 523             unsigned long octal_value = ::strtoul(oct_str, nullptr, 8);
 524             if (octal_value <= UINT8_MAX) {
 525               dst.append(1, static_cast<char>(octal_value));
 526             }
 527           }
 528           break;
 529
 530         case 'x':
 531           // hex number in the format
 532           if (isxdigit(p[1])) {
 533             ++p; // Skip the 'x'
 534
 535             // Make a string that can hold onto two hex chars plus a
 536             // NULL terminator
 537             char hex_str[3] = {*p, '\0', '\0'};
 538             if (isxdigit(p[1])) {
 539               ++p; // Skip the first of the two hex chars
 540               hex_str[1] = *p;
 541             }
 542
 543             unsigned long hex_value = strtoul(hex_str, nullptr, 16);
 544             if (hex_value <= UINT8_MAX)
 545               dst.append(1, static_cast<char>(hex_value));
 546           } else {
 547             dst.append(1, 'x');
 548           }
 549           break;
 550
 551         default:
 552           // Just desensitize any other character by just printing what came
 553           // after the '\'
 554           dst.append(1, *p);
 555           break;
 556         }
 557       }
 558     }
 559   }
 560 }
 561
 562 void Args::ExpandEscapedCharacters(const char *src, std::string &dst) {
 563   dst.clear();
 564   if (src) {
 565     for (const char *p = src; *p != '\0'; ++p) {
 566       if (llvm::isPrint(*p))
 567         dst.append(1, *p);
 568       else {
 569         switch (*p) {
 570         case '\a':
 571           dst.append("\\a");
 572           break;
 573         case '\b':
 574           dst.append("\\b");
 575           break;
 576         case '\f':
 577           dst.append("\\f");
 578           break;
 579         case '\n':
 580           dst.append("\\n");
 581           break;
 582         case '\r':
 583           dst.append("\\r");
 584           break;
 585         case '\t':
 586           dst.append("\\t");
 587           break;
 588         case '\v':
 589           dst.append("\\v");
 590           break;
 591         case '\'':
 592           dst.append("\\'");
 593           break;
 594         case '"':
 595           dst.append("\\\"");
 596           break;
 597         case '\\':
 598           dst.append("\\\\");
 599           break;
 600         default: {
 601           // Just encode as octal
 602           dst.append("\\0");
 603           char octal_str[32];
 604           snprintf(octal_str, sizeof(octal_str), "%o", *p);
 605           dst.append(octal_str);
 606         } break;
 607         }
 608       }
 609     }
 610   }
 611 }
 612
 613 std::string Args::EscapeLLDBCommandArgument(const std::string &arg,
 614                                             char quote_char) {
 615   const char *chars_to_escape = nullptr;
 616   switch (quote_char) {
 617   case '\0':
 618     chars_to_escape = " \t\\'\"`";
 619     break;
 620   case '"':
 621     chars_to_escape = "$\"`\\";
 622     break;
 623   case '`':
 624   case '\'':
 625     return arg;
 626   default:
 627     assert(false && "Unhandled quote character");
 628     return arg;
 629   }
 630
 631   std::string res;
 632   res.reserve(arg.size());
 633   for (char c : arg) {
 634     if (::strchr(chars_to_escape, c))
 635       res.push_back('\\');
 636     res.push_back(c);
 637   }
 638   return res;
 639 }
 640
 641 OptionsWithRaw::OptionsWithRaw(llvm::StringRef arg_string) {
 642   SetFromString(arg_string);
 643 }
 644
 645 void OptionsWithRaw::SetFromString(llvm::StringRef arg_string) {
 646   const llvm::StringRef original_args = arg_string;
 647
 648   size_t shift;
 649   arg_string = ltrimForArgs(arg_string, shift);
 650   std::string arg;
 651   char quote;
 652
 653   // If the string doesn't start with a dash, we just have no options and just
 654   // a raw part.
 655   if (!arg_string.starts_with("-")) {
 656     m_suffix = std::string(original_args);
 657     return;
 658   }
 659
 660   bool found_suffix = false;
 661   while (!arg_string.empty()) {
 662     // The length of the prefix before parsing.
 663     std::size_t prev_prefix_length = original_args.size() - arg_string.size();
 664
 665     // Parse the next argument from the remaining string.
 666     std::tie(arg, quote, arg_string) = ParseSingleArgument(arg_string);
 667
 668     // If we get an unquoted '--' argument, then we reached the suffix part
 669     // of the command.
 670     Args::ArgEntry entry(arg, quote, std::nullopt);
 671     if (!entry.IsQuoted() && arg == "--") {
 672       // The remaining line is the raw suffix, and the line we parsed so far
 673       // needs to be interpreted as arguments.
 674       m_has_args = true;
 675       m_suffix = std::string(arg_string);
 676       found_suffix = true;
 677
 678       // The length of the prefix after parsing.
 679       std::size_t prefix_length = original_args.size() - arg_string.size();
 680
 681       // Take the string we know contains all the arguments and actually parse
 682       // it as proper arguments.
 683       llvm::StringRef prefix = original_args.take_front(prev_prefix_length);
 684       m_args = Args(prefix);
 685       m_arg_string = prefix;
 686
 687       // We also record the part of the string that contains the arguments plus
 688       // the delimiter.
 689       m_arg_string_with_delimiter = original_args.take_front(prefix_length);
 690
 691       // As the rest of the string became the raw suffix, we are done here.
 692       break;
 693     }
 694
 695     arg_string = ltrimForArgs(arg_string, shift);
 696   }
 697
 698   // If we didn't find a suffix delimiter, the whole string is the raw suffix.
 699   if (!found_suffix)
 700     m_suffix = std::string(original_args);
 701 }