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 /* Get BSSID of given interface */
  22 static int iw_get_bssid(int iwfd, const char *ifname, char *bssid)
  23 {
  24         struct iwreq iwrq;
  25
  26         if( iw_ioctl(iwfd, ifname, SIOCGIWAP, &iwrq) >= 0 )
  27         {
  28                 unsigned char *addr = (unsigned char *)iwrq.u.ap_addr.sa_data;
  29
  30                 sprintf(bssid, "%02X:%02X:%02X:%02X:%02X:%02X",
  31                         addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
  32
  33                 return 0;
  34         }
  35
  36         return -1;
  37 }
  38
  39 /* Get channel of given interface */
  40 static int iw_get_channel(int iwfd, const char *ifname, int *channel)
  41 {
  42         int i;
  43         char buffer[sizeof(struct iw_range)];
  44         double cur_freq, cmp_freq;
  45         struct iwreq iwrq;
  46         struct iw_range *range;
  47
  48         memset(buffer, 0, sizeof(buffer));
  49
  50         iwrq.u.data.pointer = (char *)buffer;
  51         iwrq.u.data.length = sizeof(buffer);
  52         iwrq.u.data.flags = 0;
  53
  54         if( iw_ioctl(iwfd, ifname, SIOCGIWRANGE, &iwrq) < 0)
  55         {
  56                 *channel = -1;
  57                 return -1;
  58         }
  59
  60         range = (struct iw_range *)buffer;
  61
  62         if( iw_ioctl(iwfd, ifname, SIOCGIWFREQ, &iwrq) >= 0 )
  63         {
  64                 cur_freq = ((double)iwrq.u.freq.m) * pow(10, iwrq.u.freq.e);
  65                 if( cur_freq < 1000.00 )
  66                 {
  67                         *channel = (int)cur_freq;
  68                         return 0;
  69                 }
  70
  71                 for(i = 0; i < range->num_frequency; i++)
  72                 {
  73                         cmp_freq = ((double)range->freq[i].m) * pow(10, range->freq[i].e);
  74                         if( cmp_freq == cur_freq )
  75                         {
  76                                 *channel = (int)range->freq[i].i;
  77                                 return 0;
  78                         }
  79                 }
  80         }
  81
  82         *channel = -1;
  83         return -1;
  84 }
  85
  86 /* Get the (first) pid of given process name */
  87 static int find_process(const char *name)
  88 {
  89         int pid = -1;
  90         int file;
  91         char buffer[128];
  92         char cmpname[128];
  93         DIR *dir;
  94         struct dirent *entry;
  95
  96         if( (dir = opendir("/proc")) != NULL )
  97         {
  98                 snprintf(cmpname, sizeof(cmpname), "Name:\t%s\n", name);
  99
 100                 while( (entry = readdir(dir)) != NULL )
 101                 {
 102                         if( !strcmp(entry->d_name, "..") || !isdigit(*entry->d_name) )
 103                                 continue;
 104
 105                         sprintf(buffer, "/proc/%s/status", entry->d_name);
 106                         if( (file = open(buffer, O_RDONLY)) > -1 )
 107                         {
 108                                 read(file, buffer, sizeof(buffer));
 109                                 close(file);
 110
 111                                 if( strstr(buffer, cmpname) == buffer )
 112                                 {
 113                                         pid = atoi(entry->d_name);
 114
 115                                         /* Skip myself ... */
 116                                         if( pid == getpid() )
 117                                                 pid = -1;
 118                                         else
 119                                                 break;
 120                                 }
 121                         }
 122                 }
 123
 124                 closedir(dir);
 125                 return pid;
 126         }
 127
 128         syslog(LOG_CRIT, "Unable to open /proc: %s",
 129                 strerror(errno));
 130
 131         return -1;
 132 }
 133
 134 /* Check if given uci file was updated */
 135 static int check_uci_update(const char *config, time_t *mtime)
 136 {
 137         struct stat s;
 138         char path[128];
 139
 140         snprintf(path, sizeof(path), "/etc/config/%s", config);
 141         if( stat(path, &s) > -1 )
 142         {
 143                 if( (*mtime == 0) || (s.st_mtime > *mtime) )
 144                 {
 145                         *mtime = s.st_mtime;
 146                         return 1;
 147                 }
 148                 else
 149                 {
 150                         snprintf(path, sizeof(path), "/var/state/%s", config);
 151                         if( stat(path, &s) > -1 )
 152                         {
 153                                 if( (*mtime == 0) || (s.st_mtime > *mtime) )
 154                                 {
 155                                         *mtime = s.st_mtime;
 156                                         return 1;
 157                                 }
 158                         }
 159
 160                         return 0;
 161                 }
 162         }
 163
 164         return -1;
 165 }
 166
 167 /* Add tuple */
 168 static void load_wifi_uci_add_iface(const char *section, struct uci_itr_ctx *itr)
 169 {
 170         wifi_tuple_t *t;
 171         const char *ucitmp;
 172         int val = 0;
 173
 174         if( (t = (wifi_tuple_t *)malloc(sizeof(wifi_tuple_t))) != NULL )
 175         {
 176                 ucitmp = ucix_get_option(itr->ctx, "wireless", section, "ifname");
 177                 if(ucitmp)
 178                 {
 179                         strncpy(t->ifname, ucitmp, sizeof(t->ifname));
 180                         val++;
 181                 }
 182
 183                 ucitmp = ucix_get_option(itr->ctx, "wireless", section, "bssid");
 184                 if(ucitmp)
 185                 {
 186                         strncpy(t->bssid, ucitmp, sizeof(t->bssid));
 187                         val++;
 188                 }
 189
 190                 ucitmp = ucix_get_option(itr->ctx, "wireless", section, "device");
 191                 if(ucitmp)
 192                 {
 193                         ucitmp = ucix_get_option(itr->ctx, "wireless", ucitmp, "channel");
 194                         if(ucitmp)
 195                         {
 196                                 t->channel = atoi(ucitmp);
 197                                 val++;
 198                         }
 199                 }
 200
 201                 if( val == 3 )
 202                 {
 203                         syslog(LOG_INFO, "Monitoring %s: bssid=%s channel=%d",
 204                                 t->ifname, t->bssid, t->channel);
 205
 206                         t->next = itr->list;
 207                         itr->list = t;
 208                 }
 209                 else
 210                 {
 211                         free(t);
 212                 }
 213         }
 214 }
 215
 216 /* Load config */
 217 static wifi_tuple_t * load_wifi_uci(wifi_tuple_t *ifs, time_t *modtime)
 218 {
 219         struct uci_context *ctx;
 220         struct uci_itr_ctx itr;
 221         wifi_tuple_t *cur, *next;
 222
 223         if( check_uci_update("wireless", modtime) )
 224         {
 225                 syslog(LOG_INFO, "Config changed, reloading");
 226
 227                 if( (ctx = ucix_init("wireless")) != NULL )
 228                 {
 229                         if( ifs != NULL )
 230                         {
 231                                 for(cur = ifs; cur; cur = next)
 232                                 {
 233                                         next = cur->next;
 234                                         free(cur);
 235                                 }
 236                         }
 237
 238                         itr.list = NULL;
 239                         itr.ctx = ctx;
 240
 241                         ucix_for_each_section_type(ctx, "wireless", "wifi-iface",
 242                                 (void *)load_wifi_uci_add_iface, &itr);
 243
 244                         return itr.list;
 245                 }
 246         }
 247
 248         return ifs;
 249 }
 250
 251 /* Daemon implementation */
 252 static int do_daemon(void)
 253 {
 254         int iwfd;
 255         int channel;
 256         char bssid[18];
 257
 258         wifi_tuple_t *ifs = NULL, *curif;
 259         time_t modtime = 0;
 260
 261         int restart_wifi = 0;
 262         int restart_cron = 0;
 263
 264         openlog(SYSLOG_IDENT, 0, LOG_DAEMON);
 265         //daemon(1, 1);
 266
 267         if( (iwfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )
 268         {
 269                 perror("Can not open wireless control socket");
 270                 return 1;
 271         }
 272
 273         while( 1 )
 274         {
 275                 if( (ifs = load_wifi_uci(ifs, &modtime)) == NULL )
 276                 {
 277                         printf("Can not load wireless uci. File corrupt?\n");
 278                         return 1;
 279                 }
 280
 281                 /* Check crond */
 282                 if( find_process("crond") < 0 )
 283                 {
 284                         syslog(LOG_WARNING, "The crond process died, restarting");
 285                         restart_cron++;
 286                 }
 287
 288                 /* Check wireless interfaces */
 289                 for( curif = ifs; curif; curif = curif->next )
 290                 {
 291                         /* Get current channel and bssid */
 292                         if( (iw_get_bssid(iwfd, curif->ifname, bssid) == 0) &&
 293                             (iw_get_channel(iwfd, curif->ifname, &channel) == 0) )
 294                         {
 295                                 /* Check BSSID */
 296                                 if( strcasecmp(bssid, curif->bssid) != 0 )
 297                                 {
 298                                         syslog(LOG_WARNING, "BSSID mismatch on %s: current=%s wanted=%s",
 299                                                 curif->ifname, bssid, curif->bssid);
 300
 301                                         restart_wifi++;
 302                                 }
 303
 304                                 /* Check channel */
 305                                 else if( channel != curif->channel )
 306                                 {
 307                                         syslog(LOG_WARNING, "Channel mismatch on %s: current=%d wanted=%d",
 308                                                 curif->ifname, channel, curif->channel);
 309
 310                                         restart_wifi++;
 311                                 }
 312                         }
 313                         else
 314                         {
 315                                 syslog(LOG_WARNING, "Requested interface %s not present", curif->ifname);
 316                         }
 317                 }
 318
 319
 320                 /* Wifi restart required? */
 321                 if( restart_wifi >= HYSTERESIS )
 322                 {
 323                         restart_wifi = 0;
 324                         syslog(LOG_WARNING, "Restarting wireless");
 325                         EXEC(WIFI_ACTION);
 326                 }
 327
 328                 /* Cron restart required? */
 329                 if( restart_cron >= HYSTERESIS )
 330                 {
 331                         restart_cron = 0;
 332                         syslog(LOG_WARNING, "Restarting crond process");
 333                         EXEC(CRON_ACTION);
 334                 }
 335
 336                 sleep(INTERVAL);
 337         }
 338
 339         closelog();
 340         return 0;
 341 }
 342
 343
 344 int main(int argc, char *argv[])
 345 {
 346         /* Check if watchdog is running ... */
 347         if( (argc > 1) && (strcmp(argv[1], "running") == 0) )
 348         {
 349                 return (find_process(BINARY) == -1);
 350         }
 351
 352         /* Start daemon */
 353         return do_daemon();
 354 }