vtysh/vtysh_main.c

   1 /* Virtual terminal interface shell.
   2  * Copyright (C) 2000 Kunihiro Ishiguro
   3  *
   4  * This file is part of GNU Zebra.
   5  *
   6  * GNU Zebra is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2, or (at your option) any
   9  * later version.
  10  *
  11  * GNU Zebra is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <zebra.h>
  22
  23 #include <sys/un.h>
  24 #include <setjmp.h>
  25 #include <sys/wait.h>
  26 #include <pwd.h>
  27 #include <sys/file.h>
  28 #include <unistd.h>
  29
  30 #include <readline/readline.h>
  31 #include <readline/history.h>
  32
  33 /*
  34  * The append_history function only appears in newer versions
  35  * of the readline library it appears like.  Since we don't
  36  * need this just silently ignore the code on these
  37  * ancient platforms.
  38  */
  39 #if !defined HAVE_APPEND_HISTORY
  40 #define append_history(A, B)
  41 #endif
  42
  43 #include <lib/version.h>
  44 #include "getopt.h"
  45 #include "command.h"
  46 #include "memory.h"
  47 #include "linklist.h"
  48 #include "libfrr.h"
  49 #include "ferr.h"
  50 #include "lib_errors.h"
  51
  52 #include "vtysh/vtysh.h"
  53 #include "vtysh/vtysh_user.h"
  54
  55 /* VTY shell program name. */
  56 char *progname;
  57
  58 /* SUID mode */
  59 static uid_t elevuid, realuid;
  60 static gid_t elevgid, realgid;
  61
  62 #define VTYSH_CONFIG_NAME "vtysh.conf"
  63 #define FRR_CONFIG_NAME "frr.conf"
  64
  65 /* Configuration file name and directory. */
  66 static char vtysh_config[MAXPATHLEN * 3];
  67 char frr_config[MAXPATHLEN * 3];
  68 char vtydir[MAXPATHLEN];
  69 static char history_file[MAXPATHLEN];
  70
  71 /* Flag for indicate executing child command. */
  72 int execute_flag = 0;
  73
  74 /* Flag to indicate if in user/unprivileged mode. */
  75 int user_mode;
  76
  77 /* For sigsetjmp() & siglongjmp(). */
  78 static sigjmp_buf jmpbuf;
  79
  80 /* Flag for avoid recursive siglongjmp() call. */
  81 static int jmpflag = 0;
  82
  83 /* A static variable for holding the line. */
  84 static char *line_read;
  85
  86 /* Master of threads. */
  87 struct thread_master *master;
  88
  89 /* Command logging */
  90 FILE *logfile;
  91
  92 /* SIGTSTP handler.  This function care user's ^Z input. */
  93 static void sigtstp(int sig)
  94 {
  95         /* Execute "end" command. */
  96         vtysh_execute("end");
  97
  98         /* Initialize readline. */
  99         rl_initialize();
 100         printf("\n");
 101
 102         /* Check jmpflag for duplicate siglongjmp(). */
 103         if (!jmpflag)
 104                 return;
 105
 106         jmpflag = 0;
 107
 108         /* Back to main command loop. */
 109         siglongjmp(jmpbuf, 1);
 110 }
 111
 112 /* SIGINT handler.  This function care user's ^Z input.  */
 113 static void sigint(int sig)
 114 {
 115         /* Check this process is not child process. */
 116         if (!execute_flag) {
 117                 rl_initialize();
 118                 printf("\n");
 119                 rl_forced_update_display();
 120         }
 121 }
 122
 123 /* Signale wrapper for vtysh. We don't use sigevent because
 124  * vtysh doesn't use threads. TODO */
 125 static void vtysh_signal_set(int signo, void (*func)(int))
 126 {
 127         struct sigaction sig;
 128         struct sigaction osig;
 129
 130         sig.sa_handler = func;
 131         sigemptyset(&sig.sa_mask);
 132         sig.sa_flags = 0;
 133 #ifdef SA_RESTART
 134         sig.sa_flags |= SA_RESTART;
 135 #endif /* SA_RESTART */
 136
 137         sigaction(signo, &sig, &osig);
 138 }
 139
 140 /* Initialization of signal handles. */
 141 static void vtysh_signal_init(void)
 142 {
 143         vtysh_signal_set(SIGINT, sigint);
 144         vtysh_signal_set(SIGTSTP, sigtstp);
 145         vtysh_signal_set(SIGPIPE, SIG_IGN);
 146 }
 147
 148 /* Help information display. */
 149 static void usage(int status)
 150 {
 151         if (status != 0)
 152                 fprintf(stderr, "Try `%s --help' for more information.\n",
 153                         progname);
 154         else
 155                 printf("Usage : %s [OPTION...]\n\n"
 156                        "Integrated shell for FRR (version " FRR_VERSION "). \n"
 157                        "Configured with:\n    " FRR_CONFIG_ARGS "\n\n"
 158                        "-b, --boot               Execute boot startup configuration\n"
 159                        "-c, --command            Execute argument as command\n"
 160                        "-d, --daemon             Connect only to the specified daemon\n"
 161                        "-f, --inputfile          Execute commands from specific file and exit\n"
 162                        "-E, --echo               Echo prompt and command in -c mode\n"
 163                        "-C, --dryrun             Check configuration for validity and exit\n"
 164                        "-m, --markfile           Mark input file with context end\n"
 165                        "    --vty_socket         Override vty socket path\n"
 166                        "    --config_dir         Override config directory path\n"
 167                        "-N  --pathspace          Insert prefix into config & socket paths\n"
 168                        "-u  --user               Run as an unprivileged user\n"
 169                        "-w, --writeconfig        Write integrated config (frr.conf) and exit\n"
 170                        "-h, --help               Display this help and exit\n\n"
 171                        "Note that multiple commands may be executed from the command\n"
 172                        "line by passing multiple -c args, or by embedding linefeed\n"
 173                        "characters in one or more of the commands.\n\n"
 174                        "Report bugs to %s\n",
 175                        progname, FRR_BUG_ADDRESS);
 176
 177         exit(status);
 178 }
 179
 180 /* VTY shell options, we use GNU getopt library. */
 181 #define OPTION_VTYSOCK 1000
 182 #define OPTION_CONFDIR 1001
 183 struct option longopts[] = {
 184         {"boot", no_argument, NULL, 'b'},
 185         /* For compatibility with older zebra/quagga versions */
 186         {"eval", required_argument, NULL, 'e'},
 187         {"command", required_argument, NULL, 'c'},
 188         {"daemon", required_argument, NULL, 'd'},
 189         {"vty_socket", required_argument, NULL, OPTION_VTYSOCK},
 190         {"config_dir", required_argument, NULL, OPTION_CONFDIR},
 191         {"inputfile", required_argument, NULL, 'f'},
 192         {"echo", no_argument, NULL, 'E'},
 193         {"dryrun", no_argument, NULL, 'C'},
 194         {"help", no_argument, NULL, 'h'},
 195         {"noerror", no_argument, NULL, 'n'},
 196         {"mark", no_argument, NULL, 'm'},
 197         {"writeconfig", no_argument, NULL, 'w'},
 198         {"pathspace", required_argument, NULL, 'N'},
 199         {"user", no_argument, NULL, 'u'},
 200         {0}};
 201
 202 /* Read a string, and return a pointer to it.  Returns NULL on EOF. */
 203 static char *vtysh_rl_gets(void)
 204 {
 205         HIST_ENTRY *last;
 206         /* If the buffer has already been allocated, return the memory
 207          * to the free pool. */
 208         if (line_read) {
 209                 free(line_read);
 210                 line_read = NULL;
 211         }
 212
 213         /* Get a line from the user.  Change prompt according to node.  XXX. */
 214         line_read = readline(vtysh_prompt());
 215
 216         /* If the line has any text in it, save it on the history. But only if
 217          * last command in history isn't the same one. */
 218         if (line_read && *line_read) {
 219                 using_history();
 220                 last = previous_history();
 221                 if (!last || strcmp(last->line, line_read) != 0) {
 222                         add_history(line_read);
 223                         append_history(1, history_file);
 224                 }
 225         }
 226
 227         return (line_read);
 228 }
 229
 230 static void log_it(const char *line)
 231 {
 232         time_t t = time(NULL);
 233         struct tm tmp;
 234         const char *user = getenv("USER");
 235         char tod[64];
 236
 237         localtime_r(&t, &tmp);
 238         if (!user)
 239                 user = "boot";
 240
 241         strftime(tod, sizeof(tod), "%Y%m%d-%H:%M.%S", &tmp);
 242
 243         fprintf(logfile, "%s:%s %s\n", tod, user, line);
 244 }
 245
 246 static int flock_fd;
 247
 248 static void vtysh_flock_config(const char *flock_file)
 249 {
 250         int count = 0;
 251
 252         flock_fd = open(flock_file, O_RDONLY, 0644);
 253         if (flock_fd < 0) {
 254                 fprintf(stderr, "Unable to create lock file: %s, %s\n",
 255                         flock_file, safe_strerror(errno));
 256                 return;
 257         }
 258
 259         while (count < 400 && (flock(flock_fd, LOCK_EX | LOCK_NB) < 0)) {
 260                 count++;
 261                 usleep(500000);
 262         }
 263
 264         if (count >= 400)
 265                 fprintf(stderr,
 266                         "Flock of %s failed, continuing this may cause issues\n",
 267                         flock_file);
 268 }
 269
 270 static void vtysh_unflock_config(void)
 271 {
 272         flock(flock_fd, LOCK_UN);
 273         close(flock_fd);
 274 }
 275
 276 void suid_on(void)
 277 {
 278         if (elevuid != realuid && seteuid(elevuid)) {
 279                 perror("seteuid(on)");
 280                 exit(1);
 281         }
 282         if (elevgid != realgid && setegid(elevgid)) {
 283                 perror("setegid(on)");
 284                 exit(1);
 285         }
 286 }
 287
 288 void suid_off(void)
 289 {
 290         if (elevuid != realuid && seteuid(realuid)) {
 291                 perror("seteuid(off)");
 292                 exit(1);
 293         }
 294         if (elevgid != realgid && setegid(realgid)) {
 295                 perror("setegid(off)");
 296                 exit(1);
 297         }
 298 }
 299
 300 /* VTY shell main routine. */
 301 int main(int argc, char **argv, char **env)
 302 {
 303         char *p;
 304         int opt;
 305         int dryrun = 0;
 306         int boot_flag = 0;
 307         const char *daemon_name = NULL;
 308         const char *inputfile = NULL;
 309         struct cmd_rec {
 310                 char *line;
 311                 struct cmd_rec *next;
 312         } *cmd = NULL;
 313         struct cmd_rec *tail = NULL;
 314         int echo_command = 0;
 315         int no_error = 0;
 316         int markfile = 0;
 317         int writeconfig = 0;
 318         int ret = 0;
 319         char *homedir = NULL;
 320         int ditch_suid = 0;
 321         char sysconfdir[MAXPATHLEN];
 322         const char *pathspace_arg = NULL;
 323         char pathspace[MAXPATHLEN] = "";
 324
 325         /* SUID: drop down to calling user & go back up when needed */
 326         elevuid = geteuid();
 327         elevgid = getegid();
 328         realuid = getuid();
 329         realgid = getgid();
 330         suid_off();
 331
 332         user_mode = 0;          /* may be set in options processing */
 333
 334         /* Preserve name of myself. */
 335         progname = ((p = strrchr(argv[0], '/')) ? ++p : argv[0]);
 336
 337         strlcpy(sysconfdir, frr_sysconfdir, sizeof(sysconfdir));
 338
 339         frr_init_vtydir();
 340         strlcpy(vtydir, frr_vtydir, sizeof(vtydir));
 341
 342         /* Option handling. */
 343         while (1) {
 344                 opt = getopt_long(argc, argv, "be:c:d:nf:mEhCwN:u",
 345                                   longopts, 0);
 346
 347                 if (opt == EOF)
 348                         break;
 349
 350                 switch (opt) {
 351                 case 0:
 352                         break;
 353                 case 'b':
 354                         boot_flag = 1;
 355                         break;
 356                 case 'e':
 357                 case 'c': {
 358                         struct cmd_rec *cr;
 359                         cr = XMALLOC(MTYPE_TMP, sizeof(*cr));
 360                         cr->line = optarg;
 361                         cr->next = NULL;
 362                         if (tail)
 363                                 tail->next = cr;
 364                         else
 365                                 cmd = cr;
 366                         tail = cr;
 367                 } break;
 368                 case OPTION_VTYSOCK:
 369                         ditch_suid = 1; /* option disables SUID */
 370                         strlcpy(vtydir, optarg, sizeof(vtydir));
 371                         break;
 372                 case OPTION_CONFDIR:
 373                         ditch_suid = 1; /* option disables SUID */
 374                         snprintf(sysconfdir, sizeof(sysconfdir), "%s/", optarg);
 375                         break;
 376                 case 'N':
 377                         if (strchr(optarg, '/') || strchr(optarg, '.')) {
 378                                 fprintf(stderr,
 379                                         "slashes or dots are not permitted in the --pathspace option.\n");
 380                                 exit(1);
 381                         }
 382                         pathspace_arg = optarg;
 383                         snprintf(pathspace, sizeof(pathspace), "%s/", optarg);
 384                         break;
 385                 case 'd':
 386                         daemon_name = optarg;
 387                         break;
 388                 case 'f':
 389                         inputfile = optarg;
 390                         break;
 391                 case 'm':
 392                         markfile = 1;
 393                         break;
 394                 case 'n':
 395                         no_error = 1;
 396                         break;
 397                 case 'E':
 398                         echo_command = 1;
 399                         break;
 400                 case 'C':
 401                         dryrun = 1;
 402                         break;
 403                 case 'u':
 404                         user_mode = 1;
 405                         break;
 406                 case 'w':
 407                         writeconfig = 1;
 408                         break;
 409                 case 'h':
 410                         usage(0);
 411                         break;
 412                 default:
 413                         usage(1);
 414                         break;
 415                 }
 416         }
 417
 418         if (ditch_suid) {
 419                 elevuid = realuid;
 420                 elevgid = realgid;
 421         }
 422
 423         if (markfile + writeconfig + dryrun + boot_flag > 1) {
 424                 fprintf(stderr,
 425                         "Invalid combination of arguments.  Please specify at most one of:\n\t-b, -C, -m, -w\n");
 426                 return 1;
 427         }
 428         if (inputfile && (writeconfig || boot_flag)) {
 429                 fprintf(stderr,
 430                         "WARNING: Combinining the -f option with -b or -w is NOT SUPPORTED since its\nresults are inconsistent!\n");
 431         }
 432
 433         snprintf(vtysh_config, sizeof(vtysh_config), "%s%s%s", sysconfdir,
 434                  pathspace, VTYSH_CONFIG_NAME);
 435         snprintf(frr_config, sizeof(frr_config), "%s%s%s", sysconfdir,
 436                  pathspace, FRR_CONFIG_NAME);
 437
 438         if (pathspace_arg) {
 439                 strlcat(vtydir, "/", sizeof(vtydir));
 440                 strlcat(vtydir, pathspace_arg, sizeof(vtydir));
 441         }
 442
 443         /* Initialize user input buffer. */
 444         line_read = NULL;
 445         setlinebuf(stdout);
 446
 447         /* Signal and others. */
 448         vtysh_signal_init();
 449
 450         /* Make vty structure and register commands. */
 451         vtysh_init_vty();
 452         vtysh_init_cmd();
 453         vtysh_user_init();
 454         vtysh_config_init();
 455
 456         vty_init_vtysh();
 457
 458         if (!user_mode) {
 459                 /* Read vtysh configuration file before connecting to daemons.
 460                  * (file may not be readable to calling user in SUID mode) */
 461                 suid_on();
 462                 vtysh_read_config(vtysh_config);
 463                 suid_off();
 464         }
 465         /* Error code library system */
 466         log_ref_init();
 467         lib_error_init();
 468
 469         if (markfile) {
 470                 if (!inputfile) {
 471                         fprintf(stderr,
 472                                 "-f option MUST be specified with -m option\n");
 473                         return 1;
 474                 }
 475                 return (vtysh_mark_file(inputfile));
 476         }
 477
 478         /* Start execution only if not in dry-run mode */
 479         if (dryrun && !cmd) {
 480                 if (inputfile) {
 481                         ret = vtysh_read_config(inputfile);
 482                 } else {
 483                         ret = vtysh_read_config(frr_config);
 484                 }
 485
 486                 exit(ret);
 487         }
 488
 489         if (dryrun && cmd && cmd->line) {
 490                 if (!user_mode)
 491                         vtysh_execute("enable");
 492                 while (cmd) {
 493                         struct cmd_rec *cr;
 494                         char *cmdnow = cmd->line, *next;
 495                         do {
 496                                 next = strchr(cmdnow, '\n');
 497                                 if (next)
 498                                         *next++ = '\0';
 499
 500                                 if (echo_command)
 501                                         printf("%s%s\n", vtysh_prompt(),
 502                                                cmdnow);
 503
 504                                 ret = vtysh_execute_no_pager(cmdnow);
 505                                 if (!no_error
 506                                     && !(ret == CMD_SUCCESS
 507                                          || ret == CMD_SUCCESS_DAEMON
 508                                          || ret == CMD_WARNING))
 509                                         exit(1);
 510                         } while ((cmdnow = next) != NULL);
 511
 512                         cr = cmd;
 513                         cmd = cmd->next;
 514                         XFREE(MTYPE_TMP, cr);
 515                 }
 516                 exit(ret);
 517         }
 518
 519         /* Ignore error messages */
 520         if (no_error) {
 521                 if (freopen("/dev/null", "w", stdout) == NULL) {
 522                         fprintf(stderr,
 523                                 "Exiting: Failed to duplicate stdout with -n option");
 524                         exit(1);
 525                 }
 526         }
 527
 528         /* SUID: go back up elevated privs */
 529         suid_on();
 530
 531         /* Make sure we pass authentication before proceeding. */
 532         vtysh_auth();
 533
 534         /* Do not connect until we have passed authentication. */
 535         if (vtysh_connect_all(daemon_name) <= 0) {
 536                 fprintf(stderr, "Exiting: failed to connect to any daemons.\n");
 537                 if (geteuid() != 0)
 538                         fprintf(stderr,
 539                                 "Hint: if this seems wrong, try running me as a privileged user!\n");
 540                 if (no_error)
 541                         exit(0);
 542                 else
 543                         exit(1);
 544         }
 545
 546         /* SUID: back down, don't need privs further on */
 547         suid_off();
 548
 549         if (writeconfig) {
 550                 if (user_mode) {
 551                         fprintf(stderr,
 552                                 "writeconfig cannot be used when running as an unprivileged user.\n");
 553                         if (no_error)
 554                                 exit(0);
 555                         else
 556                                 exit(1);
 557                 }
 558                 vtysh_execute("enable");
 559                 return vtysh_write_config_integrated();
 560         }
 561
 562         if (inputfile) {
 563                 vtysh_flock_config(inputfile);
 564                 ret = vtysh_read_config(inputfile);
 565                 vtysh_unflock_config();
 566                 exit(ret);
 567         }
 568
 569         /*
 570          * Setup history file for use by both -c and regular input
 571          * If we can't find the home directory, then don't store
 572          * the history information
 573          */
 574         homedir = vtysh_get_home();
 575         if (homedir) {
 576                 snprintf(history_file, sizeof(history_file), "%s/.history_frr",
 577                          homedir);
 578                 if (read_history(history_file) != 0) {
 579                         int fp;
 580
 581                         fp = open(history_file, O_CREAT | O_EXCL,
 582                                   S_IRUSR | S_IWUSR);
 583                         if (fp != -1)
 584                                 close(fp);
 585
 586                         read_history(history_file);
 587                 }
 588         }
 589
 590         if (getenv("VTYSH_LOG")) {
 591                 const char *logpath = getenv("VTYSH_LOG");
 592
 593                 logfile = fopen(logpath, "a");
 594                 if (!logfile) {
 595                         fprintf(stderr, "Failed to open logfile (%s): %s\n",
 596                                 logpath, strerror(errno));
 597                         exit(1);
 598                 }
 599         }
 600
 601         /* If eval mode. */
 602         if (cmd && cmd->line) {
 603                 /* Enter into enable node. */
 604                 if (!user_mode)
 605                         vtysh_execute("enable");
 606
 607                 while (cmd != NULL) {
 608                         char *eol;
 609
 610                         while ((eol = strchr(cmd->line, '\n')) != NULL) {
 611                                 *eol = '\0';
 612
 613                                 add_history(cmd->line);
 614                                 append_history(1, history_file);
 615
 616                                 if (echo_command)
 617                                         printf("%s%s\n", vtysh_prompt(),
 618                                                cmd->line);
 619
 620                                 if (logfile)
 621                                         log_it(cmd->line);
 622
 623                                 ret = vtysh_execute_no_pager(cmd->line);
 624                                 if (!no_error
 625                                     && !(ret == CMD_SUCCESS
 626                                          || ret == CMD_SUCCESS_DAEMON
 627                                          || ret == CMD_WARNING))
 628                                         exit(1);
 629
 630                                 cmd->line = eol + 1;
 631                         }
 632
 633                         add_history(cmd->line);
 634                         append_history(1, history_file);
 635
 636                         if (echo_command)
 637                                 printf("%s%s\n", vtysh_prompt(), cmd->line);
 638
 639                         if (logfile)
 640                                 log_it(cmd->line);
 641
 642                         /*
 643                          * Parsing logic for regular commands will be different
 644                          * than for those commands requiring further
 645                          * processing, such as cli instructions terminating
 646                          * with question-mark character.
 647                          */
 648                         if (!vtysh_execute_command_questionmark(cmd->line))
 649                                 ret = CMD_SUCCESS;
 650                         else
 651                                 ret = vtysh_execute_no_pager(cmd->line);
 652
 653                         if (!no_error
 654                             && !(ret == CMD_SUCCESS || ret == CMD_SUCCESS_DAEMON
 655                                  || ret == CMD_WARNING))
 656                                 exit(1);
 657
 658                         {
 659                                 struct cmd_rec *cr;
 660                                 cr = cmd;
 661                                 cmd = cmd->next;
 662                                 XFREE(MTYPE_TMP, cr);
 663                         }
 664                 }
 665
 666                 history_truncate_file(history_file, 1000);
 667                 exit(0);
 668         }
 669
 670         /* Boot startup configuration file. */
 671         if (boot_flag) {
 672                 vtysh_flock_config(frr_config);
 673                 ret = vtysh_read_config(frr_config);
 674                 vtysh_unflock_config();
 675                 if (ret) {
 676                         fprintf(stderr,
 677                                 "Configuration file[%s] processing failure: %d\n",
 678                                 frr_config, ret);
 679                         if (no_error)
 680                                 exit(0);
 681                         else
 682                                 exit(ret);
 683                 } else
 684                         exit(0);
 685         }
 686
 687         vtysh_readline_init();
 688
 689         vty_hello(vty);
 690
 691         /* Enter into enable node. */
 692         if (!user_mode)
 693                 vtysh_execute("enable");
 694
 695         /* Preparation for longjmp() in sigtstp(). */
 696         sigsetjmp(jmpbuf, 1);
 697         jmpflag = 1;
 698
 699         /* Main command loop. */
 700         while (vtysh_rl_gets())
 701                 vtysh_execute(line_read);
 702
 703         vtysh_uninit();
 704
 705         history_truncate_file(history_file, 1000);
 706         printf("\n");
 707
 708         /* Rest in peace. */
 709         exit(0);
 710 }