kernel/register.cc

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
   5  *
   6  *  Permission to use, copy, modify, and/or distribute this software for any
   7  *  purpose with or without fee is hereby granted, provided that the above
   8  *  copyright notice and this permission notice appear in all copies.
   9  *
  10  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  */
  19
  20 #include "kernel/compatibility.h"
  21 #include "kernel/register.h"
  22 #include "kernel/log.h"
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include <stdio.h>
  26 #include <errno.h>
  27
  28 using namespace REGISTER_INTERN;
  29 #define MAX_REG_COUNT 1000
  30
  31 namespace REGISTER_INTERN
  32 {
  33         bool echo_mode = false;
  34         Pass *first_queued_pass;
  35
  36         std::map<std::string, Frontend*> frontend_register;
  37         std::map<std::string, Pass*> pass_register;
  38         std::map<std::string, Backend*> backend_register;
  39 }
  40
  41 std::vector<std::string> Frontend::next_args;
  42
  43 Pass::Pass(std::string name, std::string short_help) : pass_name(name), short_help(short_help)
  44 {
  45         next_queued_pass = first_queued_pass;
  46         first_queued_pass = this;
  47         call_counter = 0;
  48 }
  49
  50 void Pass::run_register()
  51 {
  52         log_assert(pass_register.count(pass_name) == 0);
  53         pass_register[pass_name] = this;
  54 }
  55
  56 void Pass::init_register()
  57 {
  58         while (first_queued_pass) {
  59                 first_queued_pass->run_register();
  60                 first_queued_pass = first_queued_pass->next_queued_pass;
  61         }
  62 }
  63
  64 void Pass::done_register()
  65 {
  66         frontend_register.clear();
  67         pass_register.clear();
  68         backend_register.clear();
  69         log_assert(first_queued_pass == NULL);
  70 }
  71
  72 Pass::~Pass()
  73 {
  74 }
  75
  76 void Pass::help()
  77 {
  78         log("\n");
  79         log("No help message for command `%s'.\n", pass_name.c_str());
  80         log("\n");
  81 }
  82
  83 void Pass::cmd_log_args(const std::vector<std::string> &args)
  84 {
  85         if (args.size() <= 1)
  86                 return;
  87         log("Full command line:");
  88         for (size_t i = 0; i < args.size(); i++)
  89                 log(" %s", args[i].c_str());
  90         log("\n");
  91 }
  92
  93 void Pass::cmd_error(const std::vector<std::string> &args, size_t argidx, std::string msg)
  94 {
  95         std::string command_text;
  96         int error_pos = 0;
  97
  98         for (size_t i = 0; i < args.size(); i++) {
  99                 if (i < argidx)
 100                         error_pos += args[i].size() + 1;
 101                 command_text = command_text + (command_text.empty() ? "" : " ") + args[i];
 102         }
 103
 104         log("\nSyntax error in command `%s':\n", command_text.c_str());
 105         help();
 106
 107         log_cmd_error("Command syntax error: %s\n> %s\n> %*s^\n",
 108                         msg.c_str(), command_text.c_str(), error_pos, "");
 109 }
 110
 111 void Pass::extra_args(std::vector<std::string> args, size_t argidx, RTLIL::Design *design, bool select)
 112 {
 113         for (; argidx < args.size(); argidx++)
 114         {
 115                 std::string arg = args[argidx];
 116
 117                 if (arg.substr(0, 1) == "-")
 118                         cmd_error(args, argidx, "Unkown option or option in arguments.");
 119
 120                 if (!select)
 121                         cmd_error(args, argidx, "Extra argument.");
 122
 123                 handle_extra_select_args(this, args, argidx, args.size(), design);
 124                 break;
 125         }
 126         // cmd_log_args(args);
 127 }
 128
 129 void Pass::call(RTLIL::Design *design, std::string command)
 130 {
 131         std::vector<std::string> args;
 132         char *s = strdup(command.c_str()), *sstart = s, *saveptr;
 133         s += strspn(s, " \t\r\n");
 134         if (*s == 0 || *s == '#') {
 135                 free(sstart);
 136                 return;
 137         }
 138         if (*s == '!') {
 139                 for (s++; *s == ' ' || *s == '\t'; s++) { }
 140                 char *p = s + strlen(s) - 1;
 141                 while (p >= s && (*p == '\r' || *p == '\n'))
 142                         *(p--) = 0;
 143                 log_header("Shell command: %s\n", s);
 144                 int retCode = system(s);
 145                 if (retCode != 0)
 146                         log_cmd_error("Shell command returned error code %d.\n", retCode);
 147                 free(sstart);
 148                 return;
 149         }
 150         for (char *p = strtok_r(s, " \t\r\n", &saveptr); p; p = strtok_r(NULL, " \t\r\n", &saveptr)) {
 151                 std::string str = p;
 152                 int strsz = str.size();
 153                 if (str == "#")
 154                         break;
 155                 if (strsz > 0 && str[strsz-1] == ';') {
 156                         int num_semikolon = 0;
 157                         while (strsz > 0 && str[strsz-1] == ';')
 158                                 strsz--, num_semikolon++;
 159                         if (strsz > 0)
 160                                 args.push_back(str.substr(0, strsz));
 161                         call(design, args);
 162                         args.clear();
 163                         if (num_semikolon == 2)
 164                                 call(design, "clean");
 165                         if (num_semikolon == 3)
 166                                 call(design, "clean -purge");
 167                 } else
 168                         args.push_back(str);
 169         }
 170         free(sstart);
 171         call(design, args);
 172 }
 173
 174 void Pass::call(RTLIL::Design *design, std::vector<std::string> args)
 175 {
 176         if (args.size() == 0 || args[0][0] == '#')
 177                 return;
 178
 179         if (echo_mode) {
 180                 log("%s", create_prompt(design, 0));
 181                 for (size_t i = 0; i < args.size(); i++)
 182                         log("%s%s", i ? " " : "", args[i].c_str());
 183                 log("\n");
 184         }
 185
 186         if (pass_register.count(args[0]) == 0)
 187                 log_cmd_error("No such command: %s (type 'help' for a command overview)\n", args[0].c_str());
 188
 189         size_t orig_sel_stack_pos = design->selection_stack.size();
 190         pass_register[args[0]]->call_counter++;
 191         pass_register[args[0]]->execute(args, design);
 192         while (design->selection_stack.size() > orig_sel_stack_pos)
 193                 design->selection_stack.pop_back();
 194
 195         design->check();
 196 }
 197
 198 void Pass::call_on_selection(RTLIL::Design *design, const RTLIL::Selection &selection, std::string command)
 199 {
 200         std::string backup_selected_active_module = design->selected_active_module;
 201         design->selected_active_module.clear();
 202         design->selection_stack.push_back(selection);
 203
 204         Pass::call(design, command);
 205
 206         design->selection_stack.pop_back();
 207         design->selected_active_module = backup_selected_active_module;
 208 }
 209
 210 void Pass::call_on_selection(RTLIL::Design *design, const RTLIL::Selection &selection, std::vector<std::string> args)
 211 {
 212         std::string backup_selected_active_module = design->selected_active_module;
 213         design->selected_active_module.clear();
 214         design->selection_stack.push_back(selection);
 215
 216         Pass::call(design, args);
 217
 218         design->selection_stack.pop_back();
 219         design->selected_active_module = backup_selected_active_module;
 220 }
 221
 222 void Pass::call_on_module(RTLIL::Design *design, RTLIL::Module *module, std::string command)
 223 {
 224         std::string backup_selected_active_module = design->selected_active_module;
 225         design->selected_active_module = module->name;
 226         design->selection_stack.push_back(RTLIL::Selection(false));
 227         design->selection_stack.back().select(module);
 228
 229         Pass::call(design, command);
 230
 231         design->selection_stack.pop_back();
 232         design->selected_active_module = backup_selected_active_module;
 233 }
 234
 235 void Pass::call_on_module(RTLIL::Design *design, RTLIL::Module *module, std::vector<std::string> args)
 236 {
 237         std::string backup_selected_active_module = design->selected_active_module;
 238         design->selected_active_module = module->name;
 239         design->selection_stack.push_back(RTLIL::Selection(false));
 240         design->selection_stack.back().select(module);
 241
 242         Pass::call(design, args);
 243
 244         design->selection_stack.pop_back();
 245         design->selected_active_module = backup_selected_active_module;
 246 }
 247
 248 Frontend::Frontend(std::string name, std::string short_help) : Pass("read_"+name, short_help), frontend_name(name)
 249 {
 250 }
 251
 252 void Frontend::run_register()
 253 {
 254         log_assert(pass_register.count(pass_name) == 0);
 255         pass_register[pass_name] = this;
 256
 257         log_assert(frontend_register.count(frontend_name) == 0);
 258         frontend_register[frontend_name] = this;
 259 }
 260
 261 Frontend::~Frontend()
 262 {
 263 }
 264
 265 void Frontend::execute(std::vector<std::string> args, RTLIL::Design *design)
 266 {
 267         log_assert(next_args.empty());
 268         do {
 269                 FILE *f = NULL;
 270                 next_args.clear();
 271                 call_counter++;
 272                 execute(f, std::string(), args, design);
 273                 args = next_args;
 274                 fclose(f);
 275         } while (!args.empty());
 276 }
 277
 278 FILE *Frontend::current_script_file = NULL;
 279 std::string Frontend::last_here_document;
 280
 281 void Frontend::extra_args(FILE *&f, std::string &filename, std::vector<std::string> args, size_t argidx)
 282 {
 283         bool called_with_fp = f != NULL;
 284
 285         next_args.clear();
 286         for (; argidx < args.size(); argidx++)
 287         {
 288                 std::string arg = args[argidx];
 289
 290                 if (arg.substr(0, 1) == "-")
 291                         cmd_error(args, argidx, "Unkown option or option in arguments.");
 292                 if (f != NULL)
 293                         cmd_error(args, argidx, "Extra filename argument in direct file mode.");
 294
 295                 filename = arg;
 296                 if (filename == "<<" && argidx+1 < args.size())
 297                         filename += args[++argidx];
 298                 if (filename.substr(0, 2) == "<<") {
 299                         if (Frontend::current_script_file == NULL)
 300                                 log_error("Unexpected here document '%s' outside of script!\n", filename.c_str());
 301                         if (filename.size() <= 2)
 302                                 log_error("Missing EOT marker in here document!\n");
 303                         std::string eot_marker = filename.substr(2);
 304                         last_here_document.clear();
 305                         while (1) {
 306                                 std::string buffer;
 307                                 char block[4096];
 308                                 while (1) {
 309                                         if (fgets(block, 4096, Frontend::current_script_file) == NULL)
 310                                                 log_error("Unexpected end of file in here document '%s'!\n", filename.c_str());
 311                                         buffer += block;
 312                                         if (buffer.size() > 0 && (buffer[buffer.size() - 1] == '\n' || buffer[buffer.size() - 1] == '\r'))
 313                                                 break;
 314                                 }
 315                                 int indent = buffer.find_first_not_of(" \t\r\n");
 316                                 if (buffer.substr(indent, eot_marker.size()) == eot_marker)
 317                                         break;
 318                                 last_here_document += buffer;
 319                         }
 320                         f = fmemopen((void*)last_here_document.c_str(), last_here_document.size(), "r");
 321                 } else
 322                         f = fopen(filename.c_str(), "r");
 323                 if (f == NULL)
 324                         log_cmd_error("Can't open input file `%s' for reading: %s\n", filename.c_str(), strerror(errno));
 325
 326                 for (size_t i = argidx+1; i < args.size(); i++)
 327                         if (args[i].substr(0, 1) == "-")
 328                                 cmd_error(args, i, "Found option, expected arguments.");
 329
 330                 if (argidx+1 < args.size()) {
 331                         next_args.insert(next_args.begin(), args.begin(), args.begin()+argidx);
 332                         next_args.insert(next_args.begin()+argidx, args.begin()+argidx+1, args.end());
 333                         args.erase(args.begin()+argidx+1, args.end());
 334                 }
 335                 break;
 336         }
 337         if (f == NULL)
 338                 cmd_error(args, argidx, "No filename given.");
 339
 340         if (called_with_fp)
 341                 args.push_back(filename);
 342         args[0] = pass_name;
 343         // cmd_log_args(args);
 344 }
 345
 346 void Frontend::frontend_call(RTLIL::Design *design, FILE *f, std::string filename, std::string command)
 347 {
 348         std::vector<std::string> args;
 349         char *s = strdup(command.c_str());
 350         for (char *p = strtok(s, " \t\r\n"); p; p = strtok(NULL, " \t\r\n"))
 351                 args.push_back(p);
 352         free(s);
 353         frontend_call(design, f, filename, args);
 354 }
 355
 356 void Frontend::frontend_call(RTLIL::Design *design, FILE *f, std::string filename, std::vector<std::string> args)
 357 {
 358         if (args.size() == 0)
 359                 return;
 360         if (frontend_register.count(args[0]) == 0)
 361                 log_cmd_error("No such frontend: %s\n", args[0].c_str());
 362
 363         if (f != NULL) {
 364                 frontend_register[args[0]]->call_counter++;
 365                 frontend_register[args[0]]->execute(f, filename, args, design);
 366         } else if (filename == "-") {
 367                 FILE *f_stdin = stdin; // workaround for OpenBSD 'stdin' implementation
 368                 frontend_register[args[0]]->call_counter++;
 369                 frontend_register[args[0]]->execute(f_stdin, "<stdin>", args, design);
 370         } else {
 371                 if (!filename.empty())
 372                         args.push_back(filename);
 373                 frontend_register[args[0]]->execute(args, design);
 374         }
 375
 376         design->check();
 377 }
 378
 379 Backend::Backend(std::string name, std::string short_help) :
 380                 Pass(name.substr(0, 1) == "=" ? name.substr(1) : "write_"+name, short_help),
 381                 backend_name(name.substr(0, 1) == "=" ? name.substr(1) : name)
 382 {
 383 }
 384
 385 void Backend::run_register()
 386 {
 387         log_assert(pass_register.count(pass_name) == 0);
 388         pass_register[pass_name] = this;
 389
 390         log_assert(backend_register.count(backend_name) == 0);
 391         backend_register[backend_name] = this;
 392 }
 393
 394 Backend::~Backend()
 395 {
 396 }
 397
 398 void Backend::execute(std::vector<std::string> args, RTLIL::Design *design)
 399 {
 400         FILE *f = NULL;
 401         call_counter++;
 402         execute(f, std::string(), args, design);
 403         if (f != stdout)
 404                 fclose(f);
 405 }
 406
 407 void Backend::extra_args(FILE *&f, std::string &filename, std::vector<std::string> args, size_t argidx)
 408 {
 409         bool called_with_fp = f != NULL;
 410
 411         for (; argidx < args.size(); argidx++)
 412         {
 413                 std::string arg = args[argidx];
 414
 415                 if (arg.substr(0, 1) == "-" && arg != "-")
 416                         cmd_error(args, argidx, "Unkown option or option in arguments.");
 417                 if (f != NULL)
 418                         cmd_error(args, argidx, "Extra filename argument in direct file mode.");
 419
 420                 if (arg == "-") {
 421                         filename = "<stdout>";
 422                         f = stdout;
 423                         continue;
 424                 }
 425
 426                 filename = arg;
 427                 f = fopen(filename.c_str(), "w");
 428                 if (f == NULL)
 429                         log_cmd_error("Can't open output file `%s' for writing: %s\n", filename.c_str(), strerror(errno));
 430         }
 431
 432         if (called_with_fp)
 433                 args.push_back(filename);
 434         args[0] = pass_name;
 435         // cmd_log_args(args);
 436
 437         if (f == NULL) {
 438                 filename = "<stdout>";
 439                 f = stdout;
 440         }
 441 }
 442
 443 void Backend::backend_call(RTLIL::Design *design, FILE *f, std::string filename, std::string command)
 444 {
 445         std::vector<std::string> args;
 446         char *s = strdup(command.c_str());
 447         for (char *p = strtok(s, " \t\r\n"); p; p = strtok(NULL, " \t\r\n"))
 448                 args.push_back(p);
 449         free(s);
 450         backend_call(design, f, filename, args);
 451 }
 452
 453 void Backend::backend_call(RTLIL::Design *design, FILE *f, std::string filename, std::vector<std::string> args)
 454 {
 455         if (args.size() == 0)
 456                 return;
 457         if (backend_register.count(args[0]) == 0)
 458                 log_cmd_error("No such backend: %s\n", args[0].c_str());
 459
 460         size_t orig_sel_stack_pos = design->selection_stack.size();
 461
 462         if (f != NULL) {
 463                 backend_register[args[0]]->call_counter++;
 464                 backend_register[args[0]]->execute(f, filename, args, design);
 465         } else if (filename == "-") {
 466                 FILE *f_stdout = stdout; // workaround for OpenBSD 'stdout' implementation
 467                 backend_register[args[0]]->call_counter++;
 468                 backend_register[args[0]]->execute(f_stdout, "<stdout>", args, design);
 469         } else {
 470                 if (!filename.empty())
 471                         args.push_back(filename);
 472                 backend_register[args[0]]->execute(args, design);
 473         }
 474
 475         while (design->selection_stack.size() > orig_sel_stack_pos)
 476                 design->selection_stack.pop_back();
 477
 478         design->check();
 479 }
 480
 481 struct HelpPass : public Pass {
 482         HelpPass() : Pass("help", "display help messages") { }
 483         virtual void help()
 484         {
 485                 log("\n");
 486                 log("    help  .............  list all commands\n");
 487                 log("    help <command>  ...  print help message for given command\n");
 488                 log("    help -all  ........  print complete command reference\n");
 489                 log("\n");
 490         }
 491         void escape_tex(std::string &tex)
 492         {
 493                 size_t pos = 0;
 494                 while ((pos = tex.find('_', pos)) != std::string::npos) {
 495                         tex.replace(pos, 1, "\\_");
 496                         pos += 2;
 497                 }
 498         }
 499         void write_tex(FILE *f, std::string cmd, std::string title, std::string text)
 500         {
 501                 size_t begin = text.find_first_not_of("\n"), end = text.find_last_not_of("\n");
 502                 if (begin != std::string::npos && end != std::string::npos && begin < end)
 503                         text = text.substr(begin, end-begin+1);
 504                 std::string cmd_unescaped = cmd;
 505                 escape_tex(cmd);
 506                 escape_tex(title);
 507                 fprintf(f, "\\section{%s -- %s}\n", cmd.c_str(), title.c_str());
 508                 fprintf(f, "\\label{cmd:%s}\n", cmd_unescaped.c_str());
 509                 fprintf(f, "\\begin{lstlisting}[numbers=left,frame=single]\n");
 510                 fprintf(f, "%s\n\\end{lstlisting}\n\n", text.c_str());
 511         }
 512         void escape_html(std::string &html)
 513         {
 514                 size_t pos = 0;
 515                 while ((pos = html.find_first_of("<>&", pos)) != std::string::npos)
 516                         switch (html[pos]) {
 517                         case '<':
 518                                 html.replace(pos, 1, "&lt;");
 519                                 pos += 4;
 520                                 break;
 521                         case '>':
 522                                 html.replace(pos, 1, "&gt;");
 523                                 pos += 4;
 524                                 break;
 525                         case '&':
 526                                 html.replace(pos, 1, "&amp;");
 527                                 pos += 5;
 528                                 break;
 529                         }
 530         }
 531         void write_html(FILE *idxf, std::string cmd, std::string title, std::string text)
 532         {
 533                 FILE *f = fopen(stringf("cmd_%s.in", cmd.c_str()).c_str(), "wt");
 534                 fprintf(idxf, "<li><a href=\"cmd_%s.html\"> ", cmd.c_str());
 535
 536                 escape_html(cmd);
 537                 escape_html(title);
 538                 escape_html(text);
 539
 540                 fprintf(idxf, "%s</a> <span>%s</span></a>\n", cmd.c_str(), title.c_str());
 541
 542                 fprintf(f, "@cmd_header %s@\n", cmd.c_str());
 543                 fprintf(f, "<h1>%s - %s</h1>\n", cmd.c_str(), title.c_str());
 544                 fprintf(f, "<pre>%s</pre>\n", text.c_str());
 545                 fprintf(f, "@footer@\n");
 546
 547                 fclose(f);
 548         }
 549         virtual void execute(std::vector<std::string> args, RTLIL::Design*)
 550         {
 551                 if (args.size() == 1) {
 552                         log("\n");
 553                         for (auto &it : REGISTER_INTERN::pass_register)
 554                                 log("    %-20s %s\n", it.first.c_str(), it.second->short_help.c_str());
 555                         log("\n");
 556                         log("Type 'help <command>' for more information on a command.\n");
 557                         log("\n");
 558                         return;
 559                 }
 560
 561                 if (args.size() == 2) {
 562                         if (args[1] == "-all") {
 563                                 for (auto &it : REGISTER_INTERN::pass_register) {
 564                                         log("\n\n");
 565                                         log("%s  --  %s\n", it.first.c_str(), it.second->short_help.c_str());
 566                                         for (size_t i = 0; i < it.first.size() + it.second->short_help.size() + 6; i++)
 567                                                 log("=");
 568                                         log("\n");
 569                                         it.second->help();
 570                                 }
 571                         }
 572                         // this option is undocumented as it is for internal use only
 573                         else if (args[1] == "-write-tex-command-reference-manual") {
 574                                 FILE *f = fopen("command-reference-manual.tex", "wt");
 575                                 fprintf(f, "%% Generated using the yosys 'help -write-tex-command-reference-manual' command.\n\n");
 576                                 for (auto &it : REGISTER_INTERN::pass_register) {
 577                                         size_t memsize;
 578                                         char *memptr;
 579                                         FILE *memf = open_memstream(&memptr, &memsize);
 580                                         log_files.push_back(memf);
 581                                         it.second->help();
 582                                         log_files.pop_back();
 583                                         fclose(memf);
 584                                         write_tex(f, it.first, it.second->short_help, memptr);
 585                                         free(memptr);
 586                                 }
 587                                 fclose(f);
 588                         }
 589                         // this option is undocumented as it is for internal use only
 590                         else if (args[1] == "-write-web-command-reference-manual") {
 591                                 FILE *f = fopen("templates/cmd_index.in", "wt");
 592                                 for (auto &it : REGISTER_INTERN::pass_register) {
 593                                         size_t memsize;
 594                                         char *memptr;
 595                                         FILE *memf = open_memstream(&memptr, &memsize);
 596                                         log_files.push_back(memf);
 597                                         it.second->help();
 598                                         log_files.pop_back();
 599                                         fclose(memf);
 600                                         write_html(f, it.first, it.second->short_help, memptr);
 601                                         free(memptr);
 602                                 }
 603                                 fclose(f);
 604                         }
 605                         else if (REGISTER_INTERN::pass_register.count(args[1]) == 0)
 606                                 log("No such command: %s\n", args[1].c_str());
 607                         else
 608                                 REGISTER_INTERN::pass_register.at(args[1])->help();
 609                         return;
 610                 }
 611
 612                 help();
 613         }
 614 } HelpPass;
 615
 616 struct EchoPass : public Pass {
 617         EchoPass() : Pass("echo", "turning echoing back of commands on and off") { }
 618         virtual void help()
 619         {
 620                 log("\n");
 621                 log("    echo on\n");
 622                 log("\n");
 623                 log("Print all commands to log before executing them.\n");
 624                 log("\n");
 625                 log("\n");
 626                 log("    echo off\n");
 627                 log("\n");
 628                 log("Do not print all commands to log before executing them. (default)\n");
 629                 log("\n");
 630         }
 631         virtual void execute(std::vector<std::string> args, RTLIL::Design*)
 632         {
 633                 if (args.size() > 2)
 634                         cmd_error(args, 2, "Unexpected argument.");
 635
 636                 if (args.size() == 2) {
 637                         if (args[1] == "on")
 638                                 echo_mode = true;
 639                         else if (args[1] == "off")
 640                                 echo_mode = false;
 641                         else
 642                                 cmd_error(args, 1, "Unexpected argument.");
 643                 }
 644
 645                 log("echo %s\n", echo_mode ? "on" : "off");
 646         }
 647 } EchoPass;
 648