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

/* path to look for .pl scripts, .conf should be there too */
#define SCRIPT_PATH "/home/ant/scripts:/var/scripts/"

char *find_script(char *);

int main(int argc, char **argv) {
  struct stat caller;
  int fd;
  int euid,uid,loc;
  char script[1024];
  char cmd[4096];
  char key[256];
  char conf[1024];
  char path[10240];
  char *tmp,*tmp2;
  char *scr_path;

  int i = 0;

  /* strip base name */
  if(tmp  = rindex(argv[0], '/')) {
    tmp++;
  } else {
    tmp = argv[0];
  }

  /* remove extension */
  if(tmp2 = index(tmp,'.')) {
    *tmp2 = '\0';
  }

  /* save it */
  strcpy(key, tmp);

  /* find where script with same base name is */
  scr_path = find_script(key);

  /* has path info */
  if(index(argv[0],'/')) {
    lstat(argv[0], &caller);
  } else {
    /* was called from PATH... seek it out and make sure it is legal */
    strcpy(path,(char *)getenv("PATH"));
    tmp = path;
    while(tmp = strtok(tmp,":")) {
      strcpy(cmd,tmp);
      strcat(cmd,"/");
      strcat(cmd,argv[0]);
      if(!lstat(cmd, &caller)) {
        break;
      }
      tmp = NULL;
    }
  }

  euid = geteuid();
  uid  = getuid();

  /* is link owned by suid user or root? */
  if(caller.st_uid != euid && uid != 0) {
    fprintf(stderr, "Invalid attempt to call loader from an unauthorized link, bad user, no biscuit!\n");
    exit(1);
  }


  /* build paths to script and conf */
  sprintf(conf, "%s/%s.conf", scr_path, key);
  sprintf(script, "%s/%s.pl", scr_path, key);

  /* open conf... RW if can, RO if not put on fd
     why 27 and 28? why not? doubt they will be used? */
  fd = open(conf, O_RDWR);
  if(fd >= 0)
    dup2(fd, 27);
  else {
    fd = open(conf, O_RDONLY);
    dup2(fd, 28);
  }

  close(fd);
  /* we don't want to be special any more */
  setuid(getuid());
  seteuid(getuid());
  setgid(getgid());
  setegid(getgid());

  /* become the perl script */
  execvp(script,NULL);
}

char *find_script(char *key)
{
    char *tmp;
    char path[4096];
    char cmd[1024];
    struct stat script;

    strcpy(path, SCRIPT_PATH);
    tmp = path;

    while(tmp = strtok(tmp,":")) {
      strcpy(cmd,tmp);
      strcat(cmd,"/");
      strcat(cmd,key);
      strcat(cmd,".pl");
      if(!lstat(cmd, &script)) {
        break;
      }
      tmp = NULL;
    }
    return tmp;
}