contrib/package/freifunk-watchdog/src/watchdog.c

   1 /*
   2  *   This program is free software; you can redistribute it and/or modify
   3  *   it under the terms of the GNU General Public License as published by
   4  *   the Free Software Foundation; either version 2 of the License, or
   5  *   (at your option) any later version.
   6  *
   7  *   This program is distributed in the hope that it will be useful,
   8  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  *   GNU General Public License for more details.
  11  *
  12  *   You should have received a copy of the GNU General Public License
  13  *   along with this program; if not, write to the Free Software
  14  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
  15  *
  16  *   Copyright (C) 2009 Jo-Philipp Wich <xm@subsignal.org>
  17  */
  18
  19 #include "watchdog.h"
  20
  21 /* Global watchdog fd, required by signal handler */
  22 int wdfd = -1;
  23
  24 /* Handle finished childs */
  25 static void sigchld_handler(int sig)
  26 {
  27         pid_t pid;
  28
  29         while( (pid = waitpid(-1, NULL, WNOHANG)) > 0 )
  30                 syslog(LOG_INFO, "Child returned (pid %d)", pid);
  31 }
  32
  33 /* Watchdog shutdown helper */
  34 static void shutdown_watchdog(int sig)
  35 {
  36         static const char wshutdown = WATCH_SHUTDOWN;
  37
  38         if( wdfd > -1 )
  39         {
  40                 syslog(LOG_INFO, "Stopping watchdog timer");
  41                 write(wdfd, &wshutdown, 1);
  42                 close(wdfd);
  43                 wdfd = -1;
  44         }
  45
  46         exit(0);
  47 }
  48
  49 /* Get BSSID of given interface */
  50 static int iw_get_bssid(int iwfd, const char *ifname, char *bssid)
  51 {
  52         struct iwreq iwrq;
  53
  54         if( iw_ioctl(iwfd, ifname, SIOCGIWAP, &iwrq) >= 0 )
  55         {
  56                 unsigned char *addr = (unsigned char *)iwrq.u.ap_addr.sa_data;
  57
  58                 sprintf(bssid, "%02X:%02X:%02X:%02X:%02X:%02X",
  59                         addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
  60
  61                 return 0;
  62         }
  63
  64         return -1;
  65 }
  66
  67 /* Get channel of given interface */
  68 static int iw_get_channel(int iwfd, const char *ifname, int *channel)
  69 {
  70         int i;
  71         char buffer[sizeof(struct iw_range)];
  72         double cur_freq, cmp_freq;
  73         struct iwreq iwrq;
  74         struct iw_range *range;
  75
  76         memset(buffer, 0, sizeof(buffer));
  77
  78         iwrq.u.data.pointer = (char *)buffer;
  79         iwrq.u.data.length = sizeof(buffer);
  80         iwrq.u.data.flags = 0;
  81
  82         if( iw_ioctl(iwfd, ifname, SIOCGIWRANGE, &iwrq) < 0)
  83         {
  84                 *channel = -1;
  85                 return -1;
  86         }
  87
  88         range = (struct iw_range *)buffer;
  89
  90         if( iw_ioctl(iwfd, ifname, SIOCGIWFREQ, &iwrq) >= 0 )
  91         {
  92                 cur_freq = ((double)iwrq.u.freq.m) * pow(10, iwrq.u.freq.e);
  93                 if( cur_freq < 1000.00 )
  94                 {
  95                         *channel = (int)cur_freq;
  96                         return 0;
  97                 }
  98
  99                 for(i = 0; i < range->num_frequency; i++)
 100                 {
 101                         cmp_freq = ((double)range->freq[i].m) * pow(10, range->freq[i].e);
 102                         if( cmp_freq == cur_freq )
 103                         {
 104                                 *channel = (int)range->freq[i].i;
 105                                 return 0;
 106                         }
 107                 }
 108         }
 109
 110         *channel = -1;
 111         return -1;
 112 }
 113
 114 /* Get the (first) pid of given process name */
 115 static int find_process(const char *name)
 116 {
 117         int pid = -1;
 118         int file;
 119         char buffer[128];
 120         char cmpname[128];
 121         DIR *dir;
 122         struct dirent *entry;
 123
 124         if( (dir = opendir("/proc")) != NULL )
 125         {
 126                 snprintf(cmpname, sizeof(cmpname), "Name:\t%s\n", name);
 127
 128                 while( (entry = readdir(dir)) != NULL )
 129                 {
 130                         if( !strcmp(entry->d_name, "..") || !isdigit(*entry->d_name) )
 131                                 continue;
 132
 133                         sprintf(buffer, "/proc/%s/status", entry->d_name);
 134                         if( (file = open(buffer, O_RDONLY)) > -1 )
 135                         {
 136                                 read(file, buffer, sizeof(buffer));
 137                                 close(file);
 138
 139                                 if( strstr(buffer, cmpname) == buffer )
 140                                 {
 141                                         pid = atoi(entry->d_name);
 142
 143                                         /* Skip myself ... */
 144                                         if( pid == getpid() )
 145                                                 pid = -1;
 146                                         else
 147                                                 break;
 148                                 }
 149                         }
 150                 }
 151
 152                 closedir(dir);
 153                 return pid;
 154         }
 155
 156         syslog(LOG_CRIT, "Unable to open /proc: %s",
 157                 strerror(errno));
 158
 159         return -1;
 160 }
 161
 162 /* Get the 5 minute load average */
 163 static double find_loadavg(void)
 164 {
 165         int fd;
 166         char buffer[10];
 167         double load = 0.00;
 168
 169         if( (fd = open("/proc/loadavg", O_RDONLY)) > -1 )
 170         {
 171                 if( read(fd, buffer, sizeof(buffer)) == sizeof(buffer) )
 172                         load = atof(&buffer[5]);
 173
 174                 close(fd);
 175         }
 176
 177         return load;
 178 }
 179
 180 /* Check if given uci file was updated */
 181 static int check_uci_update(const char *config, time_t *mtime)
 182 {
 183         struct stat s;
 184         char path[128];
 185
 186         snprintf(path, sizeof(path), "/var/state/%s", config);
 187         if( stat(path, &s) > -1 )
 188         {
 189                 if( (*mtime == 0) || (s.st_mtime > *mtime) )
 190                 {
 191                         *mtime = s.st_mtime;
 192                         return 1;
 193                 }
 194         }
 195
 196         return 0;
 197 }
 198
 199 /* Add tuple */
 200 static void load_wifi_uci_add_iface(const char *section, struct uci_itr_ctx *itr)
 201 {
 202         wifi_tuple_t *t;
 203         const char *ucitmp;
 204         int val = 0;
 205
 206         ucitmp = ucix_get_option(itr->ctx, "wireless", section, "mode");
 207         if( ucitmp && !strncmp(ucitmp, "adhoc", 5) )
 208         {
 209                 if( (t = (wifi_tuple_t *)malloc(sizeof(wifi_tuple_t))) != NULL )
 210                 {
 211                         ucitmp = ucix_get_option(itr->ctx, "wireless", section, "ifname");
 212                         if(ucitmp)
 213                         {
 214                                 strncpy(t->ifname, ucitmp, sizeof(t->ifname));
 215                                 val++;
 216                         }
 217
 218                         ucitmp = ucix_get_option(itr->ctx, "wireless", section, "bssid");
 219                         if(ucitmp)
 220                         {
 221                                 strncpy(t->bssid, ucitmp, sizeof(t->bssid));
 222                                 val++;
 223                         }
 224
 225                         ucitmp = ucix_get_option(itr->ctx, "wireless", section, "device");
 226                         if(ucitmp)
 227                         {
 228                                 ucitmp = ucix_get_option(itr->ctx, "wireless", ucitmp, "channel");
 229                                 if(ucitmp)
 230                                 {
 231                                         t->channel = atoi(ucitmp);
 232                                         val++;
 233                                 }
 234                         }
 235
 236                         if( val == 3 )
 237                         {
 238                                 syslog(LOG_INFO, "Monitoring %s: bssid=%s channel=%d",
 239                                         t->ifname, t->bssid, t->channel);
 240
 241                                 t->next = itr->list;
 242                                 itr->list = t;
 243                         }
 244                         else
 245                         {
 246                                 free(t);
 247                         }
 248                 }
 249         }
 250 }
 251
 252 /* Load config */
 253 static wifi_tuple_t * load_wifi_uci(wifi_tuple_t *ifs, time_t *modtime)
 254 {
 255         struct uci_context *ctx;
 256         struct uci_itr_ctx itr;
 257         wifi_tuple_t *cur, *next;
 258
 259         if( check_uci_update("wireless", modtime) )
 260         {
 261                 syslog(LOG_INFO, "Config changed, reloading");
 262
 263                 if( (ctx = ucix_init("wireless")) != NULL )
 264                 {
 265                         if( ifs != NULL )
 266                         {
 267                                 for(cur = ifs; cur; cur = next)
 268                                 {
 269                                         next = cur->next;
 270                                         free(cur);
 271                                 }
 272                         }
 273
 274                         itr.list = NULL;
 275                         itr.ctx = ctx;
 276
 277                         ucix_for_each_section_type(ctx, "wireless", "wifi-iface",
 278                                 (void *)load_wifi_uci_add_iface, &itr);
 279
 280                         return itr.list;
 281                 }
 282         }
 283
 284         return ifs;
 285 }
 286
 287 /* Daemon implementation */
 288 static int do_daemon(void)
 289 {
 290         static int wdtrigger = 1;
 291         static int wdtimeout = BASE_INTERVAL * 2;
 292         static const char wdkeepalive = WATCH_KEEPALIVE;
 293
 294         int iwfd;
 295         int channel;
 296         char bssid[18];
 297         struct sigaction sa;
 298
 299         wifi_tuple_t *ifs = NULL, *curif;
 300         time_t modtime = 0;
 301
 302         int action_intv = 0;
 303         int restart_wifi = 0;
 304         int restart_cron = 0;
 305         int restart_sshd = 0;
 306         int loadavg_panic = 0;
 307
 308         openlog(SYSLOG_IDENT, 0, LOG_DAEMON);
 309         memset(&sa, 0, sizeof(sa));
 310
 311         if( (iwfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )
 312         {
 313                 syslog(LOG_ERR, "Can not open wireless control socket: %s",
 314                         strerror(errno));
 315
 316                 return 1;
 317         }
 318
 319         if( (wdfd = open(WATCH_DEVICE, O_WRONLY)) > -1 )
 320         {
 321                 syslog(LOG_INFO, "Opened %s - polling every %i seconds",
 322                         WATCH_DEVICE, BASE_INTERVAL);
 323
 324                 /* Install signal handler to halt watchdog on shutdown */
 325                 sa.sa_handler = shutdown_watchdog;
 326                 sa.sa_flags = SA_NOCLDWAIT | SA_RESTART;
 327                 sigaction(SIGHUP,  &sa, NULL);
 328                 sigaction(SIGINT,  &sa, NULL);
 329                 sigaction(SIGPIPE, &sa, NULL);
 330                 sigaction(SIGTERM, &sa, NULL);
 331                 sigaction(SIGUSR1, &sa, NULL);
 332                 sigaction(SIGUSR2, &sa, NULL);
 333
 334                 /* Set watchdog timeout to twice the interval */
 335                 ioctl(wdfd, WDIOC_SETTIMEOUT, &wdtimeout);
 336         }
 337
 338         /* Install signal handler to reap childs */
 339         sa.sa_handler = sigchld_handler;
 340         sa.sa_flags = 0;
 341         sigaction(SIGCHLD, &sa, NULL);
 342
 343         while( 1 )
 344         {
 345                 /* Check/increment action interval */
 346                 if( ++action_intv >= ACTION_INTERVAL )
 347                 {
 348                         /* Reset action interval */
 349                         action_intv = 0;
 350
 351                         /* Check average load */
 352                         if( find_loadavg() >= LOAD_TRESHOLD )
 353                                 loadavg_panic++;
 354                         else
 355                                 loadavg_panic = 0;
 356
 357                         /* Check crond */
 358                         if( find_process("crond") < 0 )
 359                                 restart_cron++;
 360                         else
 361                                 restart_cron = 0;
 362
 363                         /* Check SSHd */
 364                         if( find_process("dropbear") < 0 )
 365                                 restart_sshd++;
 366                         else
 367                                 restart_sshd = 0;
 368
 369                         /* Check wireless interfaces */
 370                         ifs = load_wifi_uci(ifs, &modtime);
 371                         for( curif = ifs; curif; curif = curif->next )
 372                         {
 373                                 /* Get current channel and bssid */
 374                                 if( (iw_get_bssid(iwfd, curif->ifname, bssid) == 0) &&
 375                             (iw_get_channel(iwfd, curif->ifname, &channel) == 0) )
 376                                 {
 377                                         /* Check BSSID */
 378                                         if( strcasecmp(bssid, curif->bssid) != 0 )
 379                                         {
 380                                                 syslog(LOG_WARNING, "BSSID mismatch on %s: current=%s wanted=%s",
 381                                                         curif->ifname, bssid, curif->bssid);
 382
 383                                                 restart_wifi++;
 384                                         }
 385
 386                                         /* Check channel */
 387                                         else if( channel != curif->channel )
 388                                         {
 389                                                 syslog(LOG_WARNING, "Channel mismatch on %s: current=%d wanted=%d",
 390                                                         curif->ifname, channel, curif->channel);
 391
 392                                                 restart_wifi++;
 393                                         }
 394                                 }
 395                                 else
 396                                 {
 397                                         syslog(LOG_WARNING, "Requested interface %s not present", curif->ifname);
 398                                 }
 399                         }
 400
 401
 402                         /* Wifi restart required? */
 403                         if( restart_wifi >= HYSTERESIS )
 404                         {
 405                                 restart_wifi = 0;
 406                                 syslog(LOG_WARNING, "Channel or BSSID mismatch on wireless interface, restarting");
 407                                 EXEC(WIFI_ACTION);
 408                         }
 409
 410                         /* Cron restart required? */
 411                         if( restart_cron >= HYSTERESIS )
 412                         {
 413                                 restart_cron = 0;
 414                                 syslog(LOG_WARNING, "The cron process died, restarting");
 415                                 EXEC(CRON_ACTION);
 416                         }
 417
 418                         /* SSHd restart required? */
 419                         if( restart_sshd >= HYSTERESIS )
 420                         {
 421                                 restart_sshd = 0;
 422                                 syslog(LOG_WARNING, "The ssh process died, restarting");
 423                                 EXEC(SSHD_ACTION);
 424                         }
 425
 426                         /* Is there a load problem? */
 427                         if( loadavg_panic >= HYSTERESIS )
 428                         {
 429                                 syslog(LOG_EMERG, "Critical system load level, triggering reset!");
 430
 431                                 /* Try watchdog, fall back to reboot */
 432                                 if( wdfd > -1 )
 433                                         ioctl(wdfd, WDIOC_SETTIMEOUT, &wdtrigger);
 434                                 else
 435                                         EXEC(LOAD_ACTION);
 436                         }
 437                 }
 438
 439
 440                 /* Reset watchdog timer */
 441                 if( wdfd > -1 )
 442                         write(wdfd, &wdkeepalive, 1);
 443
 444                 sleep(BASE_INTERVAL);
 445         }
 446
 447         shutdown_watchdog(0);
 448         closelog();
 449
 450         return 0;
 451 }
 452
 453
 454 int main(int argc, char *argv[])
 455 {
 456         /* Check if watchdog is running ... */
 457         if( (argc > 1) && (strcmp(argv[1], "running") == 0) )
 458         {
 459                 return (find_process(BINARY) == -1);
 460         }
 461
 462         /* Start daemon */
 463         return do_daemon();
 464 }