pppd/main.c

   1 /*
   2  * main.c - Point-to-Point Protocol main module
   3  *
   4  * Copyright (c) 1989 Carnegie Mellon University.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms are permitted
   8  * provided that the above copyright notice and this paragraph are
   9  * duplicated in all such forms and that any documentation,
  10  * advertising materials, and other materials related to such
  11  * distribution and use acknowledge that the software was developed
  12  * by Carnegie Mellon University.  The name of the
  13  * University may not be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19
  20 #define RCSID   "$Id: main.c,v 1.99 2000/06/30 04:54:20 paulus Exp $"
  21
  22 #include <stdio.h>
  23 #include <ctype.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <signal.h>
  28 #include <errno.h>
  29 #include <fcntl.h>
  30 #include <syslog.h>
  31 #include <netdb.h>
  32 #include <utmp.h>
  33 #include <pwd.h>
  34 #include <setjmp.h>
  35 #include <sys/param.h>
  36 #include <sys/types.h>
  37 #include <sys/wait.h>
  38 #include <sys/time.h>
  39 #include <sys/resource.h>
  40 #include <sys/stat.h>
  41 #include <sys/socket.h>
  42 #include <netinet/in.h>
  43 #include <arpa/inet.h>
  44
  45 #include "pppd.h"
  46 #include "magic.h"
  47 #include "fsm.h"
  48 #include "lcp.h"
  49 #include "ipcp.h"
  50 #ifdef INET6
  51 #include "ipv6cp.h"
  52 #endif
  53 #include "upap.h"
  54 #include "chap.h"
  55 #include "ccp.h"
  56 #include "pathnames.h"
  57 #include "patchlevel.h"
  58 #include "tdb.h"
  59
  60 #ifdef CBCP_SUPPORT
  61 #include "cbcp.h"
  62 #endif
  63
  64 #ifdef IPX_CHANGE
  65 #include "ipxcp.h"
  66 #endif /* IPX_CHANGE */
  67 #ifdef AT_CHANGE
  68 #include "atcp.h"
  69 #endif
  70
  71 static const char rcsid[] = RCSID;
  72
  73 /* interface vars */
  74 char ifname[32];                /* Interface name */
  75 int ifunit;                     /* Interface unit number */
  76
  77 char *progname;                 /* Name of this program */
  78 char hostname[MAXNAMELEN];      /* Our hostname */
  79 static char pidfilename[MAXPATHLEN];    /* name of pid file */
  80 static char linkpidfile[MAXPATHLEN];    /* name of linkname pid file */
  81 char ppp_devnam[MAXPATHLEN];    /* name of PPP tty (maybe ttypx) */
  82 uid_t uid;                      /* Our real user-id */
  83 struct notifier *pidchange = NULL;
  84 struct notifier *phasechange = NULL;
  85 struct notifier *exitnotify = NULL;
  86 struct notifier *sigreceived = NULL;
  87
  88 int hungup;                     /* terminal has been hung up */
  89 int privileged;                 /* we're running as real uid root */
  90 int need_holdoff;               /* need holdoff period before restarting */
  91 int detached;                   /* have detached from terminal */
  92 struct stat devstat;            /* result of stat() on devnam */
  93 volatile int status;            /* exit status for pppd */
  94 int unsuccess;                  /* # unsuccessful connection attempts */
  95 int do_callback;                /* != 0 if we should do callback next */
  96 int doing_callback;             /* != 0 if we are doing callback */
  97 TDB_CONTEXT *pppdb;             /* database for storing status etc. */
  98 char db_key[32];
  99
 100 int (*holdoff_hook) __P((void)) = NULL;
 101 int (*new_phase_hook) __P((int)) = NULL;
 102
 103 static int conn_running;        /* we have a [dis]connector running */
 104 static int devfd;               /* fd of underlying device */
 105 static int fd_ppp = -1;         /* fd for talking PPP */
 106 static int fd_loop;             /* fd for getting demand-dial packets */
 107
 108 int phase;                      /* where the link is at */
 109 int kill_link;
 110 int open_ccp_flag;
 111
 112 static int waiting;
 113 static sigjmp_buf sigjmp;
 114
 115 char **script_env;              /* Env. variable values for scripts */
 116 int s_env_nalloc;               /* # words avail at script_env */
 117
 118 u_char outpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for outgoing packet */
 119 u_char inpacket_buf[PPP_MRU+PPP_HDRLEN]; /* buffer for incoming packet */
 120
 121 static int n_children;          /* # child processes still running */
 122 static int got_sigchld;         /* set if we have received a SIGCHLD */
 123
 124 int privopen;                   /* don't lock, open device as root */
 125
 126 char *no_ppp_msg = "Sorry - this system lacks PPP kernel support\n";
 127
 128 GIDSET_TYPE groups[NGROUPS_MAX];/* groups the user is in */
 129 int ngroups;                    /* How many groups valid in groups */
 130
 131 static struct timeval start_time;       /* Time when link was started. */
 132
 133 struct pppd_stats link_stats;
 134 int link_connect_time;
 135 int link_stats_valid;
 136
 137 /*
 138  * We maintain a list of child process pids and
 139  * functions to call when they exit.
 140  */
 141 struct subprocess {
 142     pid_t       pid;
 143     char        *prog;
 144     void        (*done) __P((void *));
 145     void        *arg;
 146     struct subprocess *next;
 147 };
 148
 149 static struct subprocess *children;
 150
 151 /* Prototypes for procedures local to this file. */
 152
 153 static void setup_signals __P((void));
 154 static void create_pidfile __P((void));
 155 static void create_linkpidfile __P((void));
 156 static void cleanup __P((void));
 157 static void get_input __P((void));
 158 static void calltimeout __P((void));
 159 static struct timeval *timeleft __P((struct timeval *));
 160 static void kill_my_pg __P((int));
 161 static void hup __P((int));
 162 static void term __P((int));
 163 static void chld __P((int));
 164 static void toggle_debug __P((int));
 165 static void open_ccp __P((int));
 166 static void bad_signal __P((int));
 167 static void holdoff_end __P((void *));
 168 static int reap_kids __P((int waitfor));
 169 static void update_db_entry __P((void));
 170 static void add_db_key __P((const char *));
 171 static void delete_db_key __P((const char *));
 172 static void cleanup_db __P((void));
 173
 174 extern  char    *ttyname __P((int));
 175 extern  char    *getlogin __P((void));
 176 int main __P((int, char *[]));
 177
 178 #ifdef ultrix
 179 #undef  O_NONBLOCK
 180 #define O_NONBLOCK      O_NDELAY
 181 #endif
 182
 183 #ifdef ULTRIX
 184 #define setlogmask(x)
 185 #endif
 186
 187 /*
 188  * PPP Data Link Layer "protocol" table.
 189  * One entry per supported protocol.
 190  * The last entry must be NULL.
 191  */
 192 struct protent *protocols[] = {
 193     &lcp_protent,
 194     &pap_protent,
 195     &chap_protent,
 196 #ifdef CBCP_SUPPORT
 197     &cbcp_protent,
 198 #endif
 199     &ipcp_protent,
 200 #ifdef INET6
 201     &ipv6cp_protent,
 202 #endif
 203     &ccp_protent,
 204 #ifdef IPX_CHANGE
 205     &ipxcp_protent,
 206 #endif
 207 #ifdef AT_CHANGE
 208     &atcp_protent,
 209 #endif
 210     NULL
 211 };
 212
 213 /*
 214  * If PPP_DRV_NAME is not defined, use the default "ppp" as the device name.
 215  */
 216 #if !defined(PPP_DRV_NAME)
 217 #define PPP_DRV_NAME    "ppp"
 218 #endif /* !defined(PPP_DRV_NAME) */
 219
 220 int
 221 main(argc, argv)
 222     int argc;
 223     char *argv[];
 224 {
 225     int i, fdflags, t;
 226     char *p;
 227     struct passwd *pw;
 228     struct timeval timo;
 229     sigset_t mask;
 230     struct protent *protp;
 231     struct stat statbuf;
 232     char numbuf[16];
 233
 234     new_phase(PHASE_INITIALIZE);
 235
 236     /*
 237      * Ensure that fds 0, 1, 2 are open, to /dev/null if nowhere else.
 238      * This way we can close 0, 1, 2 in detach() without clobbering
 239      * a fd that we are using.
 240      */
 241     if ((i = open("/dev/null", O_RDWR)) >= 0) {
 242         while (0 <= i && i <= 2)
 243             i = dup(i);
 244         if (i >= 0)
 245             close(i);
 246     }
 247
 248     script_env = NULL;
 249
 250     /* Initialize syslog facilities */
 251     reopen_log();
 252
 253     if (gethostname(hostname, MAXNAMELEN) < 0 ) {
 254         option_error("Couldn't get hostname: %m");
 255         exit(1);
 256     }
 257     hostname[MAXNAMELEN-1] = 0;
 258
 259     /* make sure we don't create world or group writable files. */
 260     umask(umask(0777) | 022);
 261
 262     uid = getuid();
 263     privileged = uid == 0;
 264     slprintf(numbuf, sizeof(numbuf), "%d", uid);
 265     script_setenv("ORIG_UID", numbuf, 0);
 266
 267     ngroups = getgroups(NGROUPS_MAX, groups);
 268
 269     /*
 270      * Initialize magic number generator now so that protocols may
 271      * use magic numbers in initialization.
 272      */
 273     magic_init();
 274
 275     /*
 276      * Initialize each protocol.
 277      */
 278     for (i = 0; (protp = protocols[i]) != NULL; ++i)
 279         (*protp->init)(0);
 280
 281     progname = *argv;
 282
 283     /*
 284      * Parse, in order, the system options file, the user's options file,
 285      * the tty's options file, and the command line arguments.
 286      */
 287     if (!options_from_file(_PATH_SYSOPTIONS, !privileged, 0, 1)
 288         || !options_from_user()
 289         || !parse_args(argc-1, argv+1))
 290         exit(EXIT_OPTION_ERROR);
 291
 292     /*
 293      * Work out the device name, if it hasn't already been specified.
 294      */
 295     using_pty = notty || ptycommand != NULL || pty_socket != NULL;
 296     if (!using_pty && default_device) {
 297         char *p;
 298         if (!isatty(0) || (p = ttyname(0)) == NULL) {
 299             option_error("no device specified and stdin is not a tty");
 300             exit(EXIT_OPTION_ERROR);
 301         }
 302         strlcpy(devnam, p, sizeof(devnam));
 303         if (stat(devnam, &devstat) < 0)
 304             fatal("Couldn't stat default device %s: %m", devnam);
 305     }
 306
 307     /*
 308      * Parse the tty options file.
 309      * The per-tty options file should not change
 310      * ptycommand, pty_socket, notty or devnam.
 311      */
 312     if (!using_pty && !options_for_tty())
 313         exit(EXIT_OPTION_ERROR);
 314
 315     /*
 316      * Check that we are running as root.
 317      */
 318     if (geteuid() != 0) {
 319         option_error("must be root to run %s, since it is not setuid-root",
 320                      argv[0]);
 321         exit(EXIT_NOT_ROOT);
 322     }
 323
 324     if (!ppp_available()) {
 325         option_error(no_ppp_msg);
 326         exit(EXIT_NO_KERNEL_SUPPORT);
 327     }
 328
 329     /*
 330      * Check that the options given are valid and consistent.
 331      */
 332     if (!sys_check_options())
 333         exit(EXIT_OPTION_ERROR);
 334     auth_check_options();
 335 #ifdef HAVE_MULTILINK
 336     mp_check_options();
 337 #endif
 338     for (i = 0; (protp = protocols[i]) != NULL; ++i)
 339         if (protp->check_options != NULL)
 340             (*protp->check_options)();
 341     if (demand && connect_script == 0) {
 342         option_error("connect script is required for demand-dialling\n");
 343         exit(EXIT_OPTION_ERROR);
 344     }
 345     /* default holdoff to 0 if no connect script has been given */
 346     if (connect_script == 0 && !holdoff_specified)
 347         holdoff = 0;
 348
 349     if (using_pty) {
 350         if (!default_device) {
 351             option_error("%s option precludes specifying device name",
 352                          notty? "notty": "pty");
 353             exit(EXIT_OPTION_ERROR);
 354         }
 355         if (ptycommand != NULL && notty) {
 356             option_error("pty option is incompatible with notty option");
 357             exit(EXIT_OPTION_ERROR);
 358         }
 359         if (pty_socket != NULL && (ptycommand != NULL || notty)) {
 360             option_error("socket option is incompatible with pty and notty");
 361             exit(EXIT_OPTION_ERROR);
 362         }
 363         default_device = notty;
 364         lockflag = 0;
 365         modem = 0;
 366         if (notty && log_to_fd <= 1)
 367             log_to_fd = -1;
 368     } else {
 369         /*
 370          * If the user has specified a device which is the same as
 371          * the one on stdin, pretend they didn't specify any.
 372          * If the device is already open read/write on stdin,
 373          * we assume we don't need to lock it, and we can open it as root.
 374          */
 375         if (fstat(0, &statbuf) >= 0 && S_ISCHR(statbuf.st_mode)
 376             && statbuf.st_rdev == devstat.st_rdev) {
 377             default_device = 1;
 378             fdflags = fcntl(0, F_GETFL);
 379             if (fdflags != -1 && (fdflags & O_ACCMODE) == O_RDWR)
 380                 privopen = 1;
 381         }
 382     }
 383     if (default_device)
 384         nodetach = 1;
 385
 386     /*
 387      * Don't send log messages to the serial port, it tends to
 388      * confuse the peer. :-)
 389      */
 390     if (log_to_fd >= 0 && fstat(log_to_fd, &statbuf) >= 0
 391         && S_ISCHR(statbuf.st_mode) && statbuf.st_rdev == devstat.st_rdev)
 392         log_to_fd = -1;
 393
 394     /*
 395      * Initialize system-dependent stuff.
 396      */
 397     sys_init();
 398     if (debug)
 399         setlogmask(LOG_UPTO(LOG_DEBUG));
 400
 401     pppdb = tdb_open(_PATH_PPPDB, 0, 0, O_RDWR|O_CREAT, 0644);
 402     if (pppdb != NULL) {
 403         slprintf(db_key, sizeof(db_key), "pppd%d", getpid());
 404         update_db_entry();
 405     } else {
 406         warn("Warning: couldn't open ppp database %s", _PATH_PPPDB);
 407         if (multilink) {
 408             warn("Warning: disabling multilink");
 409             multilink = 0;
 410         }
 411     }
 412
 413     /*
 414      * Detach ourselves from the terminal, if required,
 415      * and identify who is running us.
 416      */
 417     if (!nodetach && !updetach)
 418         detach();
 419     p = getlogin();
 420     if (p == NULL) {
 421         pw = getpwuid(uid);
 422         if (pw != NULL && pw->pw_name != NULL)
 423             p = pw->pw_name;
 424         else
 425             p = "(unknown)";
 426     }
 427     syslog(LOG_NOTICE, "pppd %s.%d%s started by %s, uid %d",
 428            VERSION, PATCHLEVEL, IMPLEMENTATION, p, uid);
 429     script_setenv("PPPLOGNAME", p, 0);
 430
 431     if (devnam[0])
 432         script_setenv("DEVICE", devnam, 1);
 433     slprintf(numbuf, sizeof(numbuf), "%d", getpid());
 434     script_setenv("PPPD_PID", numbuf, 1);
 435
 436     setup_signals();
 437
 438     waiting = 0;
 439
 440     create_linkpidfile();
 441
 442     /*
 443      * If we're doing dial-on-demand, set up the interface now.
 444      */
 445     if (demand) {
 446         /*
 447          * Open the loopback channel and set it up to be the ppp interface.
 448          */
 449         tdb_writelock(pppdb);
 450         fd_loop = open_ppp_loopback();
 451         set_ifunit(1);
 452         tdb_writeunlock(pppdb);
 453
 454         /*
 455          * Configure the interface and mark it up, etc.
 456          */
 457         demand_conf();
 458     }
 459
 460     do_callback = 0;
 461     for (;;) {
 462
 463         need_holdoff = 1;
 464         devfd = -1;
 465         status = EXIT_OK;
 466         ++unsuccess;
 467         doing_callback = do_callback;
 468         do_callback = 0;
 469
 470         if (demand && !doing_callback) {
 471             /*
 472              * Don't do anything until we see some activity.
 473              */
 474             kill_link = 0;
 475             new_phase(PHASE_DORMANT);
 476             demand_unblock();
 477             add_fd(fd_loop);
 478             for (;;) {
 479                 if (sigsetjmp(sigjmp, 1) == 0) {
 480                     sigprocmask(SIG_BLOCK, &mask, NULL);
 481                     if (kill_link || got_sigchld) {
 482                         sigprocmask(SIG_UNBLOCK, &mask, NULL);
 483                     } else {
 484                         waiting = 1;
 485                         sigprocmask(SIG_UNBLOCK, &mask, NULL);
 486                         wait_input(timeleft(&timo));
 487                     }
 488                 }
 489                 waiting = 0;
 490                 calltimeout();
 491                 if (kill_link) {
 492                     if (!persist)
 493                         break;
 494                     kill_link = 0;
 495                 }
 496                 if (get_loop_output())
 497                     break;
 498                 if (got_sigchld)
 499                     reap_kids(0);
 500             }
 501             remove_fd(fd_loop);
 502             if (kill_link && !persist)
 503                 break;
 504
 505             /*
 506              * Now we want to bring up the link.
 507              */
 508             demand_block();
 509             info("Starting link");
 510         }
 511
 512         new_phase(PHASE_SERIALCONN);
 513
 514         devfd = connect_tty();
 515         if (devfd < 0)
 516             goto fail;
 517
 518         /* set up the serial device as a ppp interface */
 519         tdb_writelock(pppdb);
 520         fd_ppp = establish_ppp(devfd);
 521         if (fd_ppp < 0) {
 522             tdb_writeunlock(pppdb);
 523             status = EXIT_FATAL_ERROR;
 524             goto disconnect;
 525         }
 526
 527         if (!demand && ifunit >= 0)
 528             set_ifunit(1);
 529         tdb_writeunlock(pppdb);
 530
 531         /*
 532          * Start opening the connection and wait for
 533          * incoming events (reply, timeout, etc.).
 534          */
 535         notice("Connect: %s <--> %s", ifname, ppp_devnam);
 536         gettimeofday(&start_time, NULL);
 537         link_stats_valid = 0;
 538         script_unsetenv("CONNECT_TIME");
 539         script_unsetenv("BYTES_SENT");
 540         script_unsetenv("BYTES_RCVD");
 541         lcp_lowerup(0);
 542
 543         /*
 544          * If we are initiating this connection, wait for a short
 545          * time for something from the peer.  This can avoid bouncing
 546          * our packets off his tty before he has it set up.
 547          */
 548         add_fd(fd_ppp);
 549 #ifdef XXX
 550         if (connect_delay != 0 && (connector != NULL || ptycommand != NULL)) {
 551             struct timeval t;
 552             t.tv_sec = connect_delay / 1000;
 553             t.tv_usec = connect_delay % 1000;
 554             wait_input(&t);
 555         }
 556 #endif
 557
 558         lcp_open(0);            /* Start protocol */
 559         open_ccp_flag = 0;
 560         status = EXIT_NEGOTIATION_FAILED;
 561         new_phase(PHASE_ESTABLISH);
 562         while (phase != PHASE_DEAD) {
 563             if (sigsetjmp(sigjmp, 1) == 0) {
 564                 sigprocmask(SIG_BLOCK, &mask, NULL);
 565                 if (kill_link || open_ccp_flag || got_sigchld) {
 566                     sigprocmask(SIG_UNBLOCK, &mask, NULL);
 567                 } else {
 568                     waiting = 1;
 569                     sigprocmask(SIG_UNBLOCK, &mask, NULL);
 570                     wait_input(timeleft(&timo));
 571                 }
 572             }
 573             waiting = 0;
 574             calltimeout();
 575             get_input();
 576             if (kill_link) {
 577                 lcp_close(0, "User request");
 578                 kill_link = 0;
 579             }
 580             if (open_ccp_flag) {
 581                 if (phase == PHASE_NETWORK || phase == PHASE_RUNNING) {
 582                     ccp_fsm[0].flags = OPT_RESTART; /* clears OPT_SILENT */
 583                     (*ccp_protent.open)(0);
 584                 }
 585                 open_ccp_flag = 0;
 586             }
 587             if (got_sigchld)
 588                 reap_kids(0);   /* Don't leave dead kids lying around */
 589         }
 590
 591         /*
 592          * Print connect time and statistics.
 593          */
 594         if (link_stats_valid) {
 595             int t = (link_connect_time + 5) / 6;    /* 1/10ths of minutes */
 596             info("Connect time %d.%d minutes.", t/10, t%10);
 597             info("Sent %d bytes, received %d bytes.",
 598                  link_stats.bytes_out, link_stats.bytes_in);
 599         }
 600
 601         /*
 602          * Delete pid file before disestablishing ppp.  Otherwise it
 603          * can happen that another pppd gets the same unit and then
 604          * we delete its pid file.
 605          */
 606         if (!demand) {
 607             if (pidfilename[0] != 0
 608                 && unlink(pidfilename) < 0 && errno != ENOENT)
 609                 warn("unable to delete pid file %s: %m", pidfilename);
 610             pidfilename[0] = 0;
 611         }
 612
 613         /*
 614          * If we may want to bring the link up again, transfer
 615          * the ppp unit back to the loopback.  Set the
 616          * real serial device back to its normal mode of operation.
 617          */
 618         remove_fd(fd_ppp);
 619         clean_check();
 620         if (demand)
 621             restore_loop();
 622         disestablish_ppp(devfd);
 623         fd_ppp = -1;
 624         if (!hungup)
 625             lcp_lowerdown(0);
 626         if (!demand)
 627             script_unsetenv("IFNAME");
 628
 629         /*
 630          * Run disconnector script, if requested.
 631          * XXX we may not be able to do this if the line has hung up!
 632          */
 633     disconnect:
 634         new_phase(PHASE_DISCONNECT);
 635         disconnect_tty();
 636
 637     fail:
 638         cleanup_tty();
 639
 640         if (!demand) {
 641             if (pidfilename[0] != 0
 642                 && unlink(pidfilename) < 0 && errno != ENOENT)
 643                 warn("unable to delete pid file %s: %m", pidfilename);
 644             pidfilename[0] = 0;
 645         }
 646
 647         if (!persist || (maxfail > 0 && unsuccess >= maxfail))
 648             break;
 649
 650         kill_link = 0;
 651         if (demand)
 652             demand_discard();
 653         t = need_holdoff? holdoff: 0;
 654         if (holdoff_hook)
 655             t = (*holdoff_hook)();
 656         if (t > 0) {
 657             new_phase(PHASE_HOLDOFF);
 658             TIMEOUT(holdoff_end, NULL, t);
 659             do {
 660                 if (sigsetjmp(sigjmp, 1) == 0) {
 661                     sigprocmask(SIG_BLOCK, &mask, NULL);
 662                     if (kill_link || got_sigchld) {
 663                         sigprocmask(SIG_UNBLOCK, &mask, NULL);
 664                     } else {
 665                         waiting = 1;
 666                         sigprocmask(SIG_UNBLOCK, &mask, NULL);
 667                         wait_input(timeleft(&timo));
 668                     }
 669                 }
 670                 waiting = 0;
 671                 calltimeout();
 672                 if (kill_link) {
 673                     kill_link = 0;
 674                     new_phase(PHASE_DORMANT); /* allow signal to end holdoff */
 675                 }
 676                 if (got_sigchld)
 677                     reap_kids(0);
 678             } while (phase == PHASE_HOLDOFF);
 679             if (!persist)
 680                 break;
 681         }
 682     }
 683
 684     /* Wait for scripts to finish */
 685     /* XXX should have a timeout here */
 686     while (n_children > 0) {
 687         if (debug) {
 688             struct subprocess *chp;
 689             dbglog("Waiting for %d child processes...", n_children);
 690             for (chp = children; chp != NULL; chp = chp->next)
 691                 dbglog("  script %s, pid %d", chp->prog, chp->pid);
 692         }
 693         if (reap_kids(1) < 0)
 694             break;
 695     }
 696
 697     die(status);
 698     return 0;
 699 }
 700
 701 /*
 702  * setup_signals - initialize signal handling.
 703  */
 704 static void
 705 setup_signals()
 706 {
 707     struct sigaction sa;
 708     sigset_t mask;
 709
 710     /*
 711      * Compute mask of all interesting signals and install signal handlers
 712      * for each.  Only one signal handler may be active at a time.  Therefore,
 713      * all other signals should be masked when any handler is executing.
 714      */
 715     sigemptyset(&mask);
 716     sigaddset(&mask, SIGHUP);
 717     sigaddset(&mask, SIGINT);
 718     sigaddset(&mask, SIGTERM);
 719     sigaddset(&mask, SIGCHLD);
 720     sigaddset(&mask, SIGUSR2);
 721
 722 #define SIGNAL(s, handler)      do { \
 723         sa.sa_handler = handler; \
 724         if (sigaction(s, &sa, NULL) < 0) \
 725             fatal("Couldn't establish signal handler (%d): %m", s); \
 726     } while (0)
 727
 728     sa.sa_mask = mask;
 729     sa.sa_flags = 0;
 730     SIGNAL(SIGHUP, hup);                /* Hangup */
 731     SIGNAL(SIGINT, term);               /* Interrupt */
 732     SIGNAL(SIGTERM, term);              /* Terminate */
 733     SIGNAL(SIGCHLD, chld);
 734
 735     SIGNAL(SIGUSR1, toggle_debug);      /* Toggle debug flag */
 736     SIGNAL(SIGUSR2, open_ccp);          /* Reopen CCP */
 737
 738     /*
 739      * Install a handler for other signals which would otherwise
 740      * cause pppd to exit without cleaning up.
 741      */
 742     SIGNAL(SIGABRT, bad_signal);
 743     SIGNAL(SIGALRM, bad_signal);
 744     SIGNAL(SIGFPE, bad_signal);
 745     SIGNAL(SIGILL, bad_signal);
 746     SIGNAL(SIGPIPE, bad_signal);
 747     SIGNAL(SIGQUIT, bad_signal);
 748     SIGNAL(SIGSEGV, bad_signal);
 749 #ifdef SIGBUS
 750     SIGNAL(SIGBUS, bad_signal);
 751 #endif
 752 #ifdef SIGEMT
 753     SIGNAL(SIGEMT, bad_signal);
 754 #endif
 755 #ifdef SIGPOLL
 756     SIGNAL(SIGPOLL, bad_signal);
 757 #endif
 758 #ifdef SIGPROF
 759     SIGNAL(SIGPROF, bad_signal);
 760 #endif
 761 #ifdef SIGSYS
 762     SIGNAL(SIGSYS, bad_signal);
 763 #endif
 764 #ifdef SIGTRAP
 765     SIGNAL(SIGTRAP, bad_signal);
 766 #endif
 767 #ifdef SIGVTALRM
 768     SIGNAL(SIGVTALRM, bad_signal);
 769 #endif
 770 #ifdef SIGXCPU
 771     SIGNAL(SIGXCPU, bad_signal);
 772 #endif
 773 #ifdef SIGXFSZ
 774     SIGNAL(SIGXFSZ, bad_signal);
 775 #endif
 776
 777     /*
 778      * Apparently we can get a SIGPIPE when we call syslog, if
 779      * syslogd has died and been restarted.  Ignoring it seems
 780      * be sufficient.
 781      */
 782     signal(SIGPIPE, SIG_IGN);
 783 }
 784
 785 /*
 786  * set_ifunit - do things we need to do once we know which ppp
 787  * unit we are using.
 788  */
 789 void
 790 set_ifunit(iskey)
 791     int iskey;
 792 {
 793     info("Using interface %s%d", PPP_DRV_NAME, ifunit);
 794     slprintf(ifname, sizeof(ifname), "%s%d", PPP_DRV_NAME, ifunit);
 795     script_setenv("IFNAME", ifname, iskey);
 796     if (iskey) {
 797         create_pidfile();       /* write pid to file */
 798         create_linkpidfile();
 799     }
 800 }
 801
 802 /*
 803  * detach - detach us from the controlling terminal.
 804  */
 805 void
 806 detach()
 807 {
 808     int pid;
 809     char numbuf[16];
 810
 811     if (detached)
 812         return;
 813     if ((pid = fork()) < 0) {
 814         error("Couldn't detach (fork failed: %m)");
 815         die(1);                 /* or just return? */
 816     }
 817     if (pid != 0) {
 818         /* parent */
 819         notify(pidchange, pid);
 820         exit(0);                /* parent dies */
 821     }
 822     setsid();
 823     chdir("/");
 824     close(0);
 825     close(1);
 826     close(2);
 827     detached = 1;
 828     if (!log_to_file && !log_to_specific_fd)
 829         log_to_fd = -1;
 830     /* update pid files if they have been written already */
 831     if (pidfilename[0])
 832         create_pidfile();
 833     if (linkpidfile[0])
 834         create_linkpidfile();
 835     slprintf(numbuf, sizeof(numbuf), "%d", getpid());
 836     script_setenv("PPPD_PID", numbuf, 1);
 837 }
 838
 839 /*
 840  * reopen_log - (re)open our connection to syslog.
 841  */
 842 void
 843 reopen_log()
 844 {
 845 #ifdef ULTRIX
 846     openlog("pppd", LOG_PID);
 847 #else
 848     openlog("pppd", LOG_PID | LOG_NDELAY, LOG_PPP);
 849     setlogmask(LOG_UPTO(LOG_INFO));
 850 #endif
 851 }
 852
 853 /*
 854  * Create a file containing our process ID.
 855  */
 856 static void
 857 create_pidfile()
 858 {
 859     FILE *pidfile;
 860
 861     slprintf(pidfilename, sizeof(pidfilename), "%s%s.pid",
 862              _PATH_VARRUN, ifname);
 863     if ((pidfile = fopen(pidfilename, "w")) != NULL) {
 864         fprintf(pidfile, "%d\n", getpid());
 865         (void) fclose(pidfile);
 866     } else {
 867         error("Failed to create pid file %s: %m", pidfilename);
 868         pidfilename[0] = 0;
 869     }
 870 }
 871
 872 static void
 873 create_linkpidfile()
 874 {
 875     FILE *pidfile;
 876
 877     if (linkname[0] == 0)
 878         return;
 879     script_setenv("LINKNAME", linkname, 1);
 880     slprintf(linkpidfile, sizeof(linkpidfile), "%sppp-%s.pid",
 881              _PATH_VARRUN, linkname);
 882     if ((pidfile = fopen(linkpidfile, "w")) != NULL) {
 883         fprintf(pidfile, "%d\n", getpid());
 884         if (ifname[0])
 885             fprintf(pidfile, "%s\n", ifname);
 886         (void) fclose(pidfile);
 887     } else {
 888         error("Failed to create pid file %s: %m", linkpidfile);
 889         linkpidfile[0] = 0;
 890     }
 891 }
 892
 893 /*
 894  * holdoff_end - called via a timeout when the holdoff period ends.
 895  */
 896 static void
 897 holdoff_end(arg)
 898     void *arg;
 899 {
 900     new_phase(PHASE_DORMANT);
 901 }
 902
 903 /* List of protocol names, to make our messages a little more informative. */
 904 struct protocol_list {
 905     u_short     proto;
 906     const char  *name;
 907 } protocol_list[] = {
 908     { 0x21,     "IP" },
 909     { 0x23,     "OSI Network Layer" },
 910     { 0x25,     "Xerox NS IDP" },
 911     { 0x27,     "DECnet Phase IV" },
 912     { 0x29,     "Appletalk" },
 913     { 0x2b,     "Novell IPX" },
 914     { 0x2d,     "VJ compressed TCP/IP" },
 915     { 0x2f,     "VJ uncompressed TCP/IP" },
 916     { 0x31,     "Bridging PDU" },
 917     { 0x33,     "Stream Protocol ST-II" },
 918     { 0x35,     "Banyan Vines" },
 919     { 0x39,     "AppleTalk EDDP" },
 920     { 0x3b,     "AppleTalk SmartBuffered" },
 921     { 0x3d,     "Multi-Link" },
 922     { 0x3f,     "NETBIOS Framing" },
 923     { 0x41,     "Cisco Systems" },
 924     { 0x43,     "Ascom Timeplex" },
 925     { 0x45,     "Fujitsu Link Backup and Load Balancing (LBLB)" },
 926     { 0x47,     "DCA Remote Lan" },
 927     { 0x49,     "Serial Data Transport Protocol (PPP-SDTP)" },
 928     { 0x4b,     "SNA over 802.2" },
 929     { 0x4d,     "SNA" },
 930     { 0x4f,     "IP6 Header Compression" },
 931     { 0x6f,     "Stampede Bridging" },
 932     { 0xfb,     "single-link compression" },
 933     { 0xfd,     "1st choice compression" },
 934     { 0x0201,   "802.1d Hello Packets" },
 935     { 0x0203,   "IBM Source Routing BPDU" },
 936     { 0x0205,   "DEC LANBridge100 Spanning Tree" },
 937     { 0x0231,   "Luxcom" },
 938     { 0x0233,   "Sigma Network Systems" },
 939     { 0x8021,   "Internet Protocol Control Protocol" },
 940     { 0x8023,   "OSI Network Layer Control Protocol" },
 941     { 0x8025,   "Xerox NS IDP Control Protocol" },
 942     { 0x8027,   "DECnet Phase IV Control Protocol" },
 943     { 0x8029,   "Appletalk Control Protocol" },
 944     { 0x802b,   "Novell IPX Control Protocol" },
 945     { 0x8031,   "Bridging NCP" },
 946     { 0x8033,   "Stream Protocol Control Protocol" },
 947     { 0x8035,   "Banyan Vines Control Protocol" },
 948     { 0x803d,   "Multi-Link Control Protocol" },
 949     { 0x803f,   "NETBIOS Framing Control Protocol" },
 950     { 0x8041,   "Cisco Systems Control Protocol" },
 951     { 0x8043,   "Ascom Timeplex" },
 952     { 0x8045,   "Fujitsu LBLB Control Protocol" },
 953     { 0x8047,   "DCA Remote Lan Network Control Protocol (RLNCP)" },
 954     { 0x8049,   "Serial Data Control Protocol (PPP-SDCP)" },
 955     { 0x804b,   "SNA over 802.2 Control Protocol" },
 956     { 0x804d,   "SNA Control Protocol" },
 957     { 0x804f,   "IP6 Header Compression Control Protocol" },
 958     { 0x006f,   "Stampede Bridging Control Protocol" },
 959     { 0x80fb,   "Single Link Compression Control Protocol" },
 960     { 0x80fd,   "Compression Control Protocol" },
 961     { 0xc021,   "Link Control Protocol" },
 962     { 0xc023,   "Password Authentication Protocol" },
 963     { 0xc025,   "Link Quality Report" },
 964     { 0xc027,   "Shiva Password Authentication Protocol" },
 965     { 0xc029,   "CallBack Control Protocol (CBCP)" },
 966     { 0xc081,   "Container Control Protocol" },
 967     { 0xc223,   "Challenge Handshake Authentication Protocol" },
 968     { 0xc281,   "Proprietary Authentication Protocol" },
 969     { 0,        NULL },
 970 };
 971
 972 /*
 973  * protocol_name - find a name for a PPP protocol.
 974  */
 975 const char *
 976 protocol_name(proto)
 977     int proto;
 978 {
 979     struct protocol_list *lp;
 980
 981     for (lp = protocol_list; lp->proto != 0; ++lp)
 982         if (proto == lp->proto)
 983             return lp->name;
 984     return NULL;
 985 }
 986
 987 /*
 988  * get_input - called when incoming data is available.
 989  */
 990 static void
 991 get_input()
 992 {
 993     int len, i;
 994     u_char *p;
 995     u_short protocol;
 996     struct protent *protp;
 997
 998     p = inpacket_buf;   /* point to beginning of packet buffer */
 999
1000     len = read_packet(inpacket_buf);
1001     if (len < 0)
1002         return;
1003
1004     if (len == 0) {
1005         notice("Modem hangup");
1006         hungup = 1;
1007         status = EXIT_HANGUP;
1008         lcp_lowerdown(0);       /* serial link is no longer available */
1009         link_terminated(0);
1010         return;
1011     }
1012
1013     if (debug /*&& (debugflags & DBG_INPACKET)*/)
1014         dbglog("rcvd %P", p, len);
1015
1016     if (len < PPP_HDRLEN) {
1017         MAINDEBUG(("io(): Received short packet."));
1018         return;
1019     }
1020
1021     p += 2;                             /* Skip address and control */
1022     GETSHORT(protocol, p);
1023     len -= PPP_HDRLEN;
1024
1025     /*
1026      * Toss all non-LCP packets unless LCP is OPEN.
1027      */
1028     if (protocol != PPP_LCP && lcp_fsm[0].state != OPENED) {
1029         MAINDEBUG(("get_input: Received non-LCP packet when LCP not open."));
1030         return;
1031     }
1032
1033     /*
1034      * Until we get past the authentication phase, toss all packets
1035      * except LCP, LQR and authentication packets.
1036      */
1037     if (phase <= PHASE_AUTHENTICATE
1038         && !(protocol == PPP_LCP || protocol == PPP_LQR
1039              || protocol == PPP_PAP || protocol == PPP_CHAP)) {
1040         MAINDEBUG(("get_input: discarding proto 0x%x in phase %d",
1041                    protocol, phase));
1042         return;
1043     }
1044
1045     /*
1046      * Upcall the proper protocol input routine.
1047      */
1048     for (i = 0; (protp = protocols[i]) != NULL; ++i) {
1049         if (protp->protocol == protocol && protp->enabled_flag) {
1050             (*protp->input)(0, p, len);
1051             return;
1052         }
1053         if (protocol == (protp->protocol & ~0x8000) && protp->enabled_flag
1054             && protp->datainput != NULL) {
1055             (*protp->datainput)(0, p, len);
1056             return;
1057         }
1058     }
1059
1060     if (debug) {
1061         const char *pname = protocol_name(protocol);
1062         if (pname != NULL)
1063             warn("Unsupported protocol '%s' (0x%x) received", pname, protocol);
1064         else
1065             warn("Unsupported protocol 0x%x received", protocol);
1066     }
1067     lcp_sprotrej(0, p - PPP_HDRLEN, len + PPP_HDRLEN);
1068 }
1069
1070 /*
1071  * new_phase - signal the start of a new phase of pppd's operation.
1072  */
1073 void
1074 new_phase(p)
1075     int p;
1076 {
1077     phase = p;
1078     if (new_phase_hook)
1079         (*new_phase_hook)(p);
1080     notify(phasechange, p);
1081 }
1082
1083 /*
1084  * die - clean up state and exit with the specified status.
1085  */
1086 void
1087 die(status)
1088     int status;
1089 {
1090     cleanup();
1091     notify(exitnotify, status);
1092     syslog(LOG_INFO, "Exit.");
1093     exit(status);
1094 }
1095
1096 /*
1097  * cleanup - restore anything which needs to be restored before we exit
1098  */
1099 /* ARGSUSED */
1100 static void
1101 cleanup()
1102 {
1103     sys_cleanup();
1104
1105     if (fd_ppp >= 0)
1106         disestablish_ppp(devfd);
1107     cleanup_tty();
1108
1109     if (pidfilename[0] != 0 && unlink(pidfilename) < 0 && errno != ENOENT)
1110         warn("unable to delete pid file %s: %m", pidfilename);
1111     pidfilename[0] = 0;
1112     if (linkpidfile[0] != 0 && unlink(linkpidfile) < 0 && errno != ENOENT)
1113         warn("unable to delete pid file %s: %m", linkpidfile);
1114     linkpidfile[0] = 0;
1115
1116     if (pppdb != NULL)
1117         cleanup_db();
1118 }
1119
1120 /*
1121  * update_link_stats - get stats at link termination.
1122  */
1123 void
1124 update_link_stats(u)
1125     int u;
1126 {
1127     struct timeval now;
1128     char numbuf[32];
1129
1130     if (!get_ppp_stats(u, &link_stats)
1131         || gettimeofday(&now, NULL) < 0)
1132         return;
1133     link_connect_time = now.tv_sec - start_time.tv_sec;
1134     link_stats_valid = 1;
1135
1136     slprintf(numbuf, sizeof(numbuf), "%d", link_connect_time);
1137     script_setenv("CONNECT_TIME", numbuf, 0);
1138     slprintf(numbuf, sizeof(numbuf), "%d", link_stats.bytes_out);
1139     script_setenv("BYTES_SENT", numbuf, 0);
1140     slprintf(numbuf, sizeof(numbuf), "%d", link_stats.bytes_in);
1141     script_setenv("BYTES_RCVD", numbuf, 0);
1142 }
1143
1144
1145 struct  callout {
1146     struct timeval      c_time;         /* time at which to call routine */
1147     void                *c_arg;         /* argument to routine */
1148     void                (*c_func) __P((void *)); /* routine */
1149     struct              callout *c_next;
1150 };
1151
1152 static struct callout *callout = NULL;  /* Callout list */
1153 static struct timeval timenow;          /* Current time */
1154
1155 /*
1156  * timeout - Schedule a timeout.
1157  *
1158  * Note that this timeout takes the number of seconds, NOT hz (as in
1159  * the kernel).
1160  */
1161 void
1162 timeout(func, arg, time)
1163     void (*func) __P((void *));
1164     void *arg;
1165     int time;
1166 {
1167     struct callout *newp, *p, **pp;
1168
1169     MAINDEBUG(("Timeout %p:%p in %d seconds.", func, arg, time));
1170
1171     /*
1172      * Allocate timeout.
1173      */
1174     if ((newp = (struct callout *) malloc(sizeof(struct callout))) == NULL)
1175         fatal("Out of memory in timeout()!");
1176     newp->c_arg = arg;
1177     newp->c_func = func;
1178     gettimeofday(&timenow, NULL);
1179     newp->c_time.tv_sec = timenow.tv_sec + time;
1180     newp->c_time.tv_usec = timenow.tv_usec;
1181
1182     /*
1183      * Find correct place and link it in.
1184      */
1185     for (pp = &callout; (p = *pp); pp = &p->c_next)
1186         if (newp->c_time.tv_sec < p->c_time.tv_sec
1187             || (newp->c_time.tv_sec == p->c_time.tv_sec
1188                 && newp->c_time.tv_usec < p->c_time.tv_usec))
1189             break;
1190     newp->c_next = p;
1191     *pp = newp;
1192 }
1193
1194
1195 /*
1196  * untimeout - Unschedule a timeout.
1197  */
1198 void
1199 untimeout(func, arg)
1200     void (*func) __P((void *));
1201     void *arg;
1202 {
1203     struct callout **copp, *freep;
1204
1205     MAINDEBUG(("Untimeout %p:%p.", func, arg));
1206
1207     /*
1208      * Find first matching timeout and remove it from the list.
1209      */
1210     for (copp = &callout; (freep = *copp); copp = &freep->c_next)
1211         if (freep->c_func == func && freep->c_arg == arg) {
1212             *copp = freep->c_next;
1213             free((char *) freep);
1214             break;
1215         }
1216 }
1217
1218
1219 /*
1220  * calltimeout - Call any timeout routines which are now due.
1221  */
1222 static void
1223 calltimeout()
1224 {
1225     struct callout *p;
1226
1227     while (callout != NULL) {
1228         p = callout;
1229
1230         if (gettimeofday(&timenow, NULL) < 0)
1231             fatal("Failed to get time of day: %m");
1232         if (!(p->c_time.tv_sec < timenow.tv_sec
1233               || (p->c_time.tv_sec == timenow.tv_sec
1234                   && p->c_time.tv_usec <= timenow.tv_usec)))
1235             break;              /* no, it's not time yet */
1236
1237         callout = p->c_next;
1238         (*p->c_func)(p->c_arg);
1239
1240         free((char *) p);
1241     }
1242 }
1243
1244
1245 /*
1246  * timeleft - return the length of time until the next timeout is due.
1247  */
1248 static struct timeval *
1249 timeleft(tvp)
1250     struct timeval *tvp;
1251 {
1252     if (callout == NULL)
1253         return NULL;
1254
1255     gettimeofday(&timenow, NULL);
1256     tvp->tv_sec = callout->c_time.tv_sec - timenow.tv_sec;
1257     tvp->tv_usec = callout->c_time.tv_usec - timenow.tv_usec;
1258     if (tvp->tv_usec < 0) {
1259         tvp->tv_usec += 1000000;
1260         tvp->tv_sec -= 1;
1261     }
1262     if (tvp->tv_sec < 0)
1263         tvp->tv_sec = tvp->tv_usec = 0;
1264
1265     return tvp;
1266 }
1267
1268
1269 /*
1270  * kill_my_pg - send a signal to our process group, and ignore it ourselves.
1271  */
1272 static void
1273 kill_my_pg(sig)
1274     int sig;
1275 {
1276     struct sigaction act, oldact;
1277
1278     act.sa_handler = SIG_IGN;
1279     act.sa_flags = 0;
1280     kill(0, sig);
1281     sigaction(sig, &act, &oldact);
1282     sigaction(sig, &oldact, NULL);
1283 }
1284
1285
1286 /*
1287  * hup - Catch SIGHUP signal.
1288  *
1289  * Indicates that the physical layer has been disconnected.
1290  * We don't rely on this indication; if the user has sent this
1291  * signal, we just take the link down.
1292  */
1293 static void
1294 hup(sig)
1295     int sig;
1296 {
1297     info("Hangup (SIGHUP)");
1298     kill_link = 1;
1299     if (status != EXIT_HANGUP)
1300         status = EXIT_USER_REQUEST;
1301     if (conn_running)
1302         /* Send the signal to the [dis]connector process(es) also */
1303         kill_my_pg(sig);
1304     notify(sigreceived, sig);
1305     if (waiting)
1306         siglongjmp(sigjmp, 1);
1307 }
1308
1309
1310 /*
1311  * term - Catch SIGTERM signal and SIGINT signal (^C/del).
1312  *
1313  * Indicates that we should initiate a graceful disconnect and exit.
1314  */
1315 /*ARGSUSED*/
1316 static void
1317 term(sig)
1318     int sig;
1319 {
1320     info("Terminating on signal %d.", sig);
1321     persist = 0;                /* don't try to restart */
1322     kill_link = 1;
1323     status = EXIT_USER_REQUEST;
1324     if (conn_running)
1325         /* Send the signal to the [dis]connector process(es) also */
1326         kill_my_pg(sig);
1327     notify(sigreceived, sig);
1328     if (waiting)
1329         siglongjmp(sigjmp, 1);
1330 }
1331
1332
1333 /*
1334  * chld - Catch SIGCHLD signal.
1335  * Sets a flag so we will call reap_kids in the mainline.
1336  */
1337 static void
1338 chld(sig)
1339     int sig;
1340 {
1341     got_sigchld = 1;
1342     if (waiting)
1343         siglongjmp(sigjmp, 1);
1344 }
1345
1346
1347 /*
1348  * toggle_debug - Catch SIGUSR1 signal.
1349  *
1350  * Toggle debug flag.
1351  */
1352 /*ARGSUSED*/
1353 static void
1354 toggle_debug(sig)
1355     int sig;
1356 {
1357     debug = !debug;
1358     if (debug) {
1359         setlogmask(LOG_UPTO(LOG_DEBUG));
1360     } else {
1361         setlogmask(LOG_UPTO(LOG_WARNING));
1362     }
1363 }
1364
1365
1366 /*
1367  * open_ccp - Catch SIGUSR2 signal.
1368  *
1369  * Try to (re)negotiate compression.
1370  */
1371 /*ARGSUSED*/
1372 static void
1373 open_ccp(sig)
1374     int sig;
1375 {
1376     open_ccp_flag = 1;
1377     if (waiting)
1378         siglongjmp(sigjmp, 1);
1379 }
1380
1381
1382 /*
1383  * bad_signal - We've caught a fatal signal.  Clean up state and exit.
1384  */
1385 static void
1386 bad_signal(sig)
1387     int sig;
1388 {
1389     static int crashed = 0;
1390
1391     if (crashed)
1392         _exit(127);
1393     crashed = 1;
1394     error("Fatal signal %d", sig);
1395     if (conn_running)
1396         kill_my_pg(SIGTERM);
1397     notify(sigreceived, sig);
1398     die(127);
1399 }
1400
1401
1402 /*
1403  * device_script - run a program to talk to the specified fds
1404  * (e.g. to run the connector or disconnector script).
1405  * stderr gets connected to the log fd or to the _PATH_CONNERRS file.
1406  */
1407 int
1408 device_script(program, in, out, dont_wait)
1409     char *program;
1410     int in, out;
1411     int dont_wait;
1412 {
1413     int pid, fd;
1414     int status = -1;
1415     int errfd;
1416
1417     ++conn_running;
1418     pid = fork();
1419
1420     if (pid < 0) {
1421         --conn_running;
1422         error("Failed to create child process: %m");
1423         return -1;
1424     }
1425
1426     if (pid != 0) {
1427         if (dont_wait) {
1428             record_child(pid, program, NULL, NULL);
1429             status = 0;
1430         } else {
1431             while (waitpid(pid, &status, 0) < 0) {
1432                 if (errno == EINTR)
1433                     continue;
1434                 fatal("error waiting for (dis)connection process: %m");
1435             }
1436             --conn_running;
1437         }
1438         return (status == 0 ? 0 : -1);
1439     }
1440
1441     /* here we are executing in the child */
1442     /* make sure fds 0, 1, 2 are occupied */
1443     while ((fd = dup(in)) >= 0) {
1444         if (fd > 2) {
1445             close(fd);
1446             break;
1447         }
1448     }
1449
1450     /* dup in and out to fds > 2 */
1451     in = dup(in);
1452     out = dup(out);
1453     if (log_to_fd >= 0) {
1454         errfd = dup(log_to_fd);
1455     } else {
1456         errfd = open(_PATH_CONNERRS, O_WRONLY | O_APPEND | O_CREAT, 0600);
1457     }
1458
1459     /* close fds 0 - 2 and any others we can think of */
1460     close(0);
1461     close(1);
1462     close(2);
1463     sys_close();
1464     tty_close_fds();
1465     closelog();
1466
1467     /* dup the in, out, err fds to 0, 1, 2 */
1468     dup2(in, 0);
1469     close(in);
1470     dup2(out, 1);
1471     close(out);
1472     if (errfd >= 0) {
1473         dup2(errfd, 2);
1474         close(errfd);
1475     }
1476
1477     setuid(uid);
1478     if (getuid() != uid) {
1479         error("setuid failed");
1480         exit(1);
1481     }
1482     setgid(getgid());
1483     execl("/bin/sh", "sh", "-c", program, (char *)0);
1484     error("could not exec /bin/sh: %m");
1485     exit(99);
1486     /* NOTREACHED */
1487 }
1488
1489
1490 /*
1491  * run-program - execute a program with given arguments,
1492  * but don't wait for it.
1493  * If the program can't be executed, logs an error unless
1494  * must_exist is 0 and the program file doesn't exist.
1495  * Returns -1 if it couldn't fork, 0 if the file doesn't exist
1496  * or isn't an executable plain file, or the process ID of the child.
1497  * If done != NULL, (*done)(arg) will be called later (within
1498  * reap_kids) iff the return value is > 0.
1499  */
1500 pid_t
1501 run_program(prog, args, must_exist, done, arg)
1502     char *prog;
1503     char **args;
1504     int must_exist;
1505     void (*done) __P((void *));
1506     void *arg;
1507 {
1508     int pid;
1509     struct stat sbuf;
1510
1511     /*
1512      * First check if the file exists and is executable.
1513      * We don't use access() because that would use the
1514      * real user-id, which might not be root, and the script
1515      * might be accessible only to root.
1516      */
1517     errno = EINVAL;
1518     if (stat(prog, &sbuf) < 0 || !S_ISREG(sbuf.st_mode)
1519         || (sbuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0) {
1520         if (must_exist || errno != ENOENT)
1521             warn("Can't execute %s: %m", prog);
1522         return 0;
1523     }
1524
1525     pid = fork();
1526     if (pid == -1) {
1527         error("Failed to create child process for %s: %m", prog);
1528         return -1;
1529     }
1530     if (pid == 0) {
1531         int new_fd;
1532
1533         /* Leave the current location */
1534         (void) setsid();        /* No controlling tty. */
1535         (void) umask (S_IRWXG|S_IRWXO);
1536         (void) chdir ("/");     /* no current directory. */
1537         setuid(0);              /* set real UID = root */
1538         setgid(getegid());
1539
1540         /* Ensure that nothing of our device environment is inherited. */
1541         sys_close();
1542         closelog();
1543         close (0);
1544         close (1);
1545         close (2);
1546         tty_close_fds();
1547
1548         /* Don't pass handles to the PPP device, even by accident. */
1549         new_fd = open (_PATH_DEVNULL, O_RDWR);
1550         if (new_fd >= 0) {
1551             if (new_fd != 0) {
1552                 dup2  (new_fd, 0); /* stdin <- /dev/null */
1553                 close (new_fd);
1554             }
1555             dup2 (0, 1); /* stdout -> /dev/null */
1556             dup2 (0, 2); /* stderr -> /dev/null */
1557         }
1558
1559 #ifdef BSD
1560         /* Force the priority back to zero if pppd is running higher. */
1561         if (setpriority (PRIO_PROCESS, 0, 0) < 0)
1562             warn("can't reset priority to 0: %m");
1563 #endif
1564
1565         /* SysV recommends a second fork at this point. */
1566
1567         /* run the program */
1568         execve(prog, args, script_env);
1569         if (must_exist || errno != ENOENT) {
1570             /* have to reopen the log, there's nowhere else
1571                for the message to go. */
1572             reopen_log();
1573             syslog(LOG_ERR, "Can't execute %s: %m", prog);
1574             closelog();
1575         }
1576         _exit(-1);
1577     }
1578
1579     if (debug)
1580         dbglog("Script %s started (pid %d)", prog, pid);
1581     record_child(pid, prog, done, arg);
1582
1583     return pid;
1584 }
1585
1586
1587 /*
1588  * record_child - add a child process to the list for reap_kids
1589  * to use.
1590  */
1591 void
1592 record_child(pid, prog, done, arg)
1593     int pid;
1594     char *prog;
1595     void (*done) __P((void *));
1596     void *arg;
1597 {
1598     struct subprocess *chp;
1599
1600     ++n_children;
1601
1602     chp = (struct subprocess *) malloc(sizeof(struct subprocess));
1603     if (chp == NULL) {
1604         warn("losing track of %s process", prog);
1605     } else {
1606         chp->pid = pid;
1607         chp->prog = prog;
1608         chp->done = done;
1609         chp->arg = arg;
1610         chp->next = children;
1611         children = chp;
1612     }
1613 }
1614
1615
1616 /*
1617  * reap_kids - get status from any dead child processes,
1618  * and log a message for abnormal terminations.
1619  */
1620 static int
1621 reap_kids(waitfor)
1622     int waitfor;
1623 {
1624     int pid, status;
1625     struct subprocess *chp, **prevp;
1626
1627     got_sigchld = 0;
1628     if (n_children == 0)
1629         return 0;
1630     while ((pid = waitpid(-1, &status, (waitfor? 0: WNOHANG))) != -1
1631            && pid != 0) {
1632         for (prevp = &children; (chp = *prevp) != NULL; prevp = &chp->next) {
1633             if (chp->pid == pid) {
1634                 --n_children;
1635                 *prevp = chp->next;
1636                 break;
1637             }
1638         }
1639         if (WIFSIGNALED(status)) {
1640             warn("Child process %s (pid %d) terminated with signal %d",
1641                  (chp? chp->prog: "??"), pid, WTERMSIG(status));
1642         } else if (debug)
1643             dbglog("Script %s finished (pid %d), status = 0x%x",
1644                    (chp? chp->prog: "??"), pid, status);
1645         if (chp && chp->done)
1646             (*chp->done)(chp->arg);
1647         if (chp)
1648             free(chp);
1649     }
1650     if (pid == -1) {
1651         if (errno == ECHILD)
1652             return -1;
1653         if (errno != EINTR)
1654             error("Error waiting for child process: %m");
1655     }
1656     return 0;
1657 }
1658
1659 /*
1660  * add_notifier - add a new function to be called when something happens.
1661  */
1662 void
1663 add_notifier(notif, func, arg)
1664     struct notifier **notif;
1665     notify_func func;
1666     void *arg;
1667 {
1668     struct notifier *np;
1669
1670     np = malloc(sizeof(struct notifier));
1671     if (np == 0)
1672         novm("notifier struct");
1673     np->next = *notif;
1674     np->func = func;
1675     np->arg = arg;
1676     *notif = np;
1677 }
1678
1679 /*
1680  * remove_notifier - remove a function from the list of things to
1681  * be called when something happens.
1682  */
1683 void
1684 remove_notifier(notif, func, arg)
1685     struct notifier **notif;
1686     notify_func func;
1687     void *arg;
1688 {
1689     struct notifier *np;
1690
1691     for (; (np = *notif) != 0; notif = &np->next) {
1692         if (np->func == func && np->arg == arg) {
1693             *notif = np->next;
1694             free(np);
1695             break;
1696         }
1697     }
1698 }
1699
1700 /*
1701  * notify - call a set of functions registered with add_notify.
1702  */
1703 void
1704 notify(notif, val)
1705     struct notifier *notif;
1706     int val;
1707 {
1708     struct notifier *np;
1709
1710     while ((np = notif) != 0) {
1711         notif = np->next;
1712         (*np->func)(np->arg, val);
1713     }
1714 }
1715
1716 /*
1717  * novm - log an error message saying we ran out of memory, and die.
1718  */
1719 void
1720 novm(msg)
1721     char *msg;
1722 {
1723     fatal("Virtual memory exhausted allocating %s\n", msg);
1724 }
1725
1726 /*
1727  * script_setenv - set an environment variable value to be used
1728  * for scripts that we run (e.g. ip-up, auth-up, etc.)
1729  */
1730 void
1731 script_setenv(var, value, iskey)
1732     char *var, *value;
1733     int iskey;
1734 {
1735     size_t varl = strlen(var);
1736     size_t vl = varl + strlen(value) + 2;
1737     int i;
1738     char *p, *newstring;
1739
1740     newstring = (char *) malloc(vl+1);
1741     if (newstring == 0)
1742         return;
1743     *newstring++ = iskey;
1744     slprintf(newstring, vl, "%s=%s", var, value);
1745
1746     /* check if this variable is already set */
1747     if (script_env != 0) {
1748         for (i = 0; (p = script_env[i]) != 0; ++i) {
1749             if (strncmp(p, var, varl) == 0 && p[varl] == '=') {
1750                 if (p[-1] && pppdb != NULL)
1751                     delete_db_key(p);
1752                 free(p-1);
1753                 script_env[i] = newstring;
1754                 if (iskey && pppdb != NULL)
1755                     add_db_key(newstring);
1756                 update_db_entry();
1757                 return;
1758             }
1759         }
1760     } else {
1761         /* no space allocated for script env. ptrs. yet */
1762         i = 0;
1763         script_env = (char **) malloc(16 * sizeof(char *));
1764         if (script_env == 0)
1765             return;
1766         s_env_nalloc = 16;
1767     }
1768
1769     /* reallocate script_env with more space if needed */
1770     if (i + 1 >= s_env_nalloc) {
1771         int new_n = i + 17;
1772         char **newenv = (char **) realloc((void *)script_env,
1773                                           new_n * sizeof(char *));
1774         if (newenv == 0)
1775             return;
1776         script_env = newenv;
1777         s_env_nalloc = new_n;
1778     }
1779
1780     script_env[i] = newstring;
1781     script_env[i+1] = 0;
1782
1783     if (pppdb != NULL) {
1784         if (iskey)
1785             add_db_key(newstring);
1786         update_db_entry();
1787     }
1788 }
1789
1790 /*
1791  * script_unsetenv - remove a variable from the environment
1792  * for scripts.
1793  */
1794 void
1795 script_unsetenv(var)
1796     char *var;
1797 {
1798     int vl = strlen(var);
1799     int i;
1800     char *p;
1801
1802     if (script_env == 0)
1803         return;
1804     for (i = 0; (p = script_env[i]) != 0; ++i) {
1805         if (strncmp(p, var, vl) == 0 && p[vl] == '=') {
1806             if (p[-1] && pppdb != NULL)
1807                 delete_db_key(p);
1808             free(p-1);
1809             while ((script_env[i] = script_env[i+1]) != 0)
1810                 ++i;
1811             break;
1812         }
1813     }
1814     if (pppdb != NULL)
1815         update_db_entry();
1816 }
1817
1818 /*
1819  * update_db_entry - update our entry in the database.
1820  */
1821 static void
1822 update_db_entry()
1823 {
1824     TDB_DATA key, dbuf;
1825     int vlen, i;
1826     char *p, *q, *vbuf;
1827
1828     if (script_env == NULL)
1829         return;
1830     vlen = 0;
1831     for (i = 0; (p = script_env[i]) != 0; ++i)
1832         vlen += strlen(p) + 1;
1833     vbuf = malloc(vlen);
1834     if (vbuf == 0)
1835         novm("database entry");
1836     q = vbuf;
1837     for (i = 0; (p = script_env[i]) != 0; ++i)
1838         q += slprintf(q, vbuf + vlen - q, "%s;", p);
1839
1840     key.dptr = db_key;
1841     key.dsize = strlen(db_key);
1842     dbuf.dptr = vbuf;
1843     dbuf.dsize = vlen;
1844     if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
1845         error("tdb_store failed: %s", tdb_error(pppdb));
1846
1847 }
1848
1849 /*
1850  * add_db_key - add a key that we can use to look up our database entry.
1851  */
1852 static void
1853 add_db_key(str)
1854     const char *str;
1855 {
1856     TDB_DATA key, dbuf;
1857
1858     key.dptr = (char *) str;
1859     key.dsize = strlen(str);
1860     dbuf.dptr = db_key;
1861     dbuf.dsize = strlen(db_key);
1862     if (tdb_store(pppdb, key, dbuf, TDB_REPLACE))
1863         error("tdb_store key failed: %s", tdb_error(pppdb));
1864 }
1865
1866 /*
1867  * delete_db_key - delete a key for looking up our database entry.
1868  */
1869 static void
1870 delete_db_key(str)
1871     const char *str;
1872 {
1873     TDB_DATA key;
1874
1875     key.dptr = (char *) str;
1876     key.dsize = strlen(str);
1877     tdb_delete(pppdb, key);
1878 }
1879
1880 /*
1881  * cleanup_db - delete all the entries we put in the database.
1882  */
1883 static void
1884 cleanup_db()
1885 {
1886     TDB_DATA key;
1887     int i;
1888     char *p;
1889
1890     key.dptr = db_key;
1891     key.dsize = strlen(db_key);
1892     tdb_delete(pppdb, key);
1893     for (i = 0; (p = script_env[i]) != 0; ++i)
1894         if (p[-1])
1895             delete_db_key(p);
1896 }