#include <stdio.h>
#include <netdb.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netinet/in.h>

extern char **argvec;

#include "utils.h"
#include "config.h"
#include "strings.h"

#include "hostname.h"

#if defined(HOSTNAMES) && !defined(SYNC_HOSTNAMES)

int hostname_fd;

void fork_hostname_process(void)
{
 int p[2];
 int pid;
 int npend;
 int pend[1024];
 int i;
 int j;
 fd_set rfds;

 socketpair(AF_UNIX,SOCK_STREAM,0,&p[0]);
 pid = fork();
 if (pid)
  { hostname_fd = p[0];
    close(p[1]);
    return;
  }
 signal(SIGINT,SIG_IGN);
 hostname_fd = p[1];
 close(p[0]);
 for (i=getdtablesize()-1;i>=0;i--)
  { if ((i != hostname_fd) && (i != 2)) close(i);
  }
 npend = 0;
 while (1)
  { while (1)
     { pid = wait3(0,WNOHANG,0);
       if (pid <= 0) break;
     }
    FD_ZERO(&rfds);
    FD_SET(hostname_fd,&rfds);
    j = 0;
    for (i=0;i<npend;i++)
     { if (pend[i] >= 0)
	{ FD_SET(pend[i],&rfds);
	  if (j != i) pend[j] = pend[i];
	  j ++;
	}
     }
    npend = j;
    i = select(FD_SETSIZE,&rfds,0,0,0);
    if (i < 0)
     { if (errno == EINTR) continue;
       fprintf(stderr,"%s: select: %s\n",argvec[0],strerror(errno));
       exit(0);
     }
    if (FD_ISSET(hostname_fd,&rfds))
     { struct in_addr ia;
       if (Read(hostname_fd,&ia,sizeof(ia)) < 0) exit(0);
       socketpair(AF_UNIX,SOCK_STREAM,0,&p[0]);
       pend[npend++] = p[0];
       pid = fork();
       if (pid == 0)
	{ struct hostent *hp;
	  close(hostname_fd);
	  for (i=npend-1;i>=0;i--) close(pend[i]);
	  hp = gethostbyaddr((void *)&ia,sizeof(ia),AF_INET);
	  write(p[1],&ia,sizeof(ia));
	  if (hp)
	   { unsigned char len;
	     unsigned int ilen;
	     ilen = strlen(hp->h_name);
	     len = (ilen > 255) ? 255 : ilen;
	     write(p[1],&len,1);
	     if (len) write(p[1],hp->h_name,len);
	   }
	  else
	   { write(p[1],"",1);
	   }
	  exit(0);
	}
       close(p[1]);
       continue;
     }
    for (i=npend-1;i>=0;i--)
     { if (FD_ISSET(pend[i],&rfds))
#define IAS sizeof(struct in_addr)
	{ unsigned char buf[IAS+1+255];
#define SETERR(s) (buf[IAS]=strlen(strcpy(&buf[IAS+1],(s))))
	  if (Read(pend[i],&buf[0],IAS) == 0)
	   { if (Read(pend[i],&buf[IAS],1) == 0)
	      { if (Read(pend[i],&buf[IAS+1],buf[IAS]) == 0)
		 { 
		 }
		else
		 { SETERR("(error A)");
		 }
	      }
	     else
	      { SETERR("(error B)");
	      }
	   }
	  else
	   { SETERR("(error C)");
	   }
	  write(hostname_fd,&buf[0],IAS+1+buf[IAS]);
#undef SETERR
#undef IAS
	  close(pend[i]);
	  pend[i] = -1;
	}
     }
  }
}

#endif