/*********************************************************************
                                                                  v.1
    archangel.c           
      angels the angel, in case of machine reboots, or other ills.
    
    Requirments:
      angel in ewtoo
      crontab access
      
    Installing:  
      place this file in src directory
      
      edit Makefile to have it to compile archangel.c, 
         useing the 'angel' procedure as a template
      
      follow procs for installing extras in angel.c
      
      follow procs for adding entry to crontab
      
      modify the defines in archangel.c
        to get the MATCH_STRING type   ps -x   from shell
        while the angel is running, and replace in code.
        to get ROOT, use the ROOT dirs for LIVE and CODING.
        modify BOOT_ANGEL and ARCH_LOCK as needed for your
        talker's directory setup
    
    Notes:
      if you run this on a system other than linux, or with
      a funky 'ps' command, the command line options to it
      will have to be modified

   Bug Reports:
      send to phypor@benland.muc.edu
      
    Licences:   
      freely distributable and modifiable,
      as long as this full header kept with
      any distributions and any modifications
      to original marked plainly so.
   
    Warrenty:
      non, the author <phypor> is in no way responsible
      for use, misuse, abuse, or any other actions
      misactions, reactions of this code,
      its provided as is.
   
    Author:
      phypor <phypor@benland.muc.edu>

        "if it breaks you get to keep both pieces"
                                   ~old linux proverb;)



**************** installing entry in crontab ****************
from shell invoke     
   crontab -e

and put
# every ten mins, of every hour, of every day
*/10 * * * * /home/clouds/live/bin/archangel &

in the file, modifing as wanted to change how often this runs
also modify the path to the live archangel for Your Talker

**************** end installing in crontab ******************


************ installing lock file into angel.c **************

   ** at the top of the file put this,    **
   ** modify to how looks in archangel.c  **
#define ARCH_LOCK "out/archlock"





   if (chdir(ROOT) < 0)
      error("Can't change to root directory.\n");
    ** add this line **
   unlink (ARCH_LOCK);
    *******************
   if (strcmp(angel_name, argv[0]))





         log("error", "Total barf.. crashing lots... Giving up");
         log("error", "Question is, what now ??");
            ** add these two lines **
         alive_fd = creat (ARCH_LOCK, S_IRUSR | S_IWUSR);
         close (alive_fd);
            *************************
         exit(-1);

**************** end installing in angel.c ******************



********************************************************************/


#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>


void    log ( char *, char * );

#ifdef CODING
  #define MATCH_STRING     ".oO> Clouds <Oo. Angel watching port 5005"
  #define ROOT             "/home/clouds/coding/"
#elif LIVE
  #define MATCH_STRING     ".oO> Clouds <Oo. Angel watching port 5010"
  #define ROOT             "/home/clouds/live/"
#else
  #error Must have LIVE or CODING defined in archangel
#endif

#define BOOT_ANGEL       "bin/angel &"
#define ARCH_LOCK        "out/archlock"

#define XS_OK            0
#define XS_NO_POPEN      1
#define XS_BAD_DIR       2
#define XS_LOCK_EXISTS   3


void main ( int argc, char * argv[] )
{
   FILE         *command;
   char          line[1024];
   struct stat   sbuf;

   if (chdir (ROOT) < 0)
      exit (XS_BAD_DIR);

    /* if arch lock file exists, the server barfd 
       dont keep trying to boot it, dammit!
    */
   if (stat (ARCH_LOCK, &sbuf) >= 0)
      exit (XS_LOCK_EXISTS); 

   command = popen("ps -x", "r");

   if (!command)
   {
      log ("archangel", "Erg!  Failed to open ps process.");
      exit (XS_NO_POPEN);
   }
   for (memset (line, 0, 1024);
        fgets (line, 1024, command);
        memset (line, 0, 1024))
   {
      if (strstr (line, MATCH_STRING) || strstr (MATCH_STRING, line))
      {
           /* angel is running on process list */
         wait (0);  /* wait for child to exit */
         fclose (command);
         exit (XS_OK);
      }
   }

   wait (0);
   fclose (command);
   log ("archangel", "Angel down, booting...");
   system (BOOT_ANGEL);
   exit (XS_OK);
}



void log ( char * filename, char * str )
{
   int       fd;
   time_t    tm;
   char      path[160];
   char      out[1024];

   memset (path, 0, 160);
   sprintf (path, "logs/%s.log", filename);
   fd = open (path, O_CREAT | O_WRONLY | O_SYNC | O_APPEND,
                    S_IRUSR | S_IWUSR);
   if (fd < 0)
      return;

   memset (out, 0, 1024);
   tm = time (0);
   sprintf (out, "%s   %s\n", ctime (&tm), str);
   write (fd, out, strlen(out));

   close(fd);
}