1.1 --- a/tools/misc/xen_netwatch.c	Mon Nov 10 16:40:53 2003 +0000
     1.2 +++ b/tools/misc/xen_netwatch.c	Mon Nov 10 16:49:52 2003 +0000
     1.3 @@ -1,7 +1,13 @@
     1.4  /******************************************************************************
     1.5 - * netwatch.c
     1.6 + * xen_netwatch.c
     1.7   * 
     1.8 - * Watch for network interfaces needing frobbing.
     1.9 + * Watch for network interfaces changing state (IFF_UP), and call a standard
    1.10 + * script '/etc/xen/netwatch <ifname> up|down'. Logging from the netwatch
    1.11 + * daemon is written to '/var/xen/netwatch' -- other programs can therefore
    1.12 + * watch that file to take action on interface state changes.
    1.13 + * 
    1.14 + * Note that, apart from the names of the default action script and log file,
    1.15 + * this program is not actually Xen-dependent.
    1.16   * 
    1.17   * Copyright (c) 2003, K A Fraser
    1.18   */
    1.19 @@ -24,6 +30,9 @@
    1.20  #include <unistd.h>
    1.21  #include <time.h>
    1.22  
    1.23 +#define DEFAULT_SCRIPT  "/var/xen/netwatch"
    1.24 +#define DEFAULT_LOGFILE "/etc/xen/netwatch"
    1.25 +
    1.26  #define LOG(_f, _a...)                                  \
    1.27      do {                                                \
    1.28          time_t now = time(NULL);                        \
    1.29 @@ -56,11 +65,10 @@ void handle_child_death(int dummy)
    1.30  
    1.31  int main(int argc, char **argv)
    1.32  {
    1.33 -    char *logfile = "/var/xen/netwatch";
    1.34 -    char *scriptfile = "/etc/xen/netwatch";
    1.35 +    char *logfile = DEFAULT_LOGFILE;
    1.36 +    char *scriptfile = DEFAULT_SCRIPT;
    1.37      FILE *logfd;
    1.38 -    int nlfd, unixfd, bytes;
    1.39 -    int last_index = ~0;
    1.40 +    int i, nlfd, unixfd, bytes, last_index = ~0;
    1.41      unsigned int last_flags = ~0;
    1.42      char buffer[8192];
    1.43      struct sockaddr_nl nladdr;
    1.44 @@ -69,6 +77,25 @@ int main(int argc, char **argv)
    1.45      struct ifreq ifr;
    1.46      struct sigaction sigchld;
    1.47  
    1.48 +    for ( i = 1; i < argc; i++ )
    1.49 +    {
    1.50 +        if ( strncmp("-s", argv[i], 2) == 0 )
    1.51 +        {
    1.52 +            scriptfile = argv[i] + 2;
    1.53 +        }
    1.54 +        else if ( strncmp("-l", argv[i], 2) == 0 )
    1.55 +        {
    1.56 +            logfile = argv[i] + 2;
    1.57 +        }
    1.58 +        else
    1.59 +        {
    1.60 +            printf("Usage: %s [-s<script>] [-l<logfile>]\n", argv[0]);
    1.61 +            printf("Default script:   %s\n", scriptfile);
    1.62 +            printf("Default log file: %s\n", logfile);
    1.63 +            return 0;
    1.64 +        }
    1.65 +    }
    1.66 +
    1.67      /* Ensure that zombie children are reaped. */
    1.68      memset(&sigchld, 0, sizeof(sigchld));
    1.69      sigchld.sa_handler = handle_child_death;
    1.70 @@ -145,7 +172,10 @@ int main(int argc, char **argv)
    1.71                !(nlmsg->nlmsg_flags & NLMSG_DONE);
    1.72                nlmsg = NLMSG_NEXT(nlmsg, bytes) )
    1.73          {
    1.74 -            /* This termination condition works. NLMSG_DONE doesn't always. */
    1.75 +            /*
    1.76 +             * This termination condition works. NLMSG_DONE doesn't always.
    1.77 +             * This therefore works around a Linux bug.
    1.78 +             */
    1.79              if ( nlmsg->nlmsg_len == 0 )
    1.80                  break;
    1.81  
    1.82 @@ -161,7 +191,7 @@ int main(int argc, char **argv)
    1.83              if ( !(ifi->ifi_change & IFF_UP) )
    1.84                  continue;
    1.85  
    1.86 -            /* Ignore duplicate messages. */
    1.87 +            /* Ignore duplicate messages. This works around a Linux bug.*/
    1.88              if ( (last_index == ifr.ifr_ifindex) &&
    1.89                   (last_flags == ifi->ifi_flags) )
    1.90                  continue;
    1.91 @@ -184,7 +214,6 @@ int main(int argc, char **argv)
    1.92                  return 1;
    1.93              case -1:
    1.94                  LOG("Error forking to exec script");
    1.95 -                break;
    1.96              default:
    1.97                  break;
    1.98              }