#include <poll.h>
#include <stdio.h>
#include <netdb.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/uio.h>
#include <sys/file.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/resource.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;
int hostname_px;

void fork_hostname_process(void)
{
 int p[2];
 int pid;
 int npend;
#define MAXPEND 1024
 int pend[MAXPEND];
 int npoll;
 struct pollfd pfds[MAXPEND+1];
 int npfds;
 int i;
 int j;
 struct rlimit rl;

 if (getrlimit(RLIMIT_NOFILE,&rl) == 0)
  { rl.rlim_cur = rl.rlim_max;
    setrlimit(RLIMIT_NOFILE,&rl);
  }
 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;
     }
    j = 0;
    for (i=0;i<npend;i++)
     { if (pend[i] >= 0)
	{ if (j != i) pend[j] = pend[i];
	  pfds[j].fd = pend[j];
	  pfds[j].events = POLLIN | POLLRDNORM;
	  j ++;
	}
     }
    npend = j;
    npoll = j;
    if (npoll < MAXPEND)
     { pfds[j].fd = hostname_fd;
       pfds[j].events = POLLIN | POLLRDNORM;
       j ++;
     }
    npfds = j;
    i = poll(&pfds[0],npfds,INFTIM);
    if (i < 0)
     { if (errno == EINTR) continue;
       fprintf(stderr,"%s: poll: %s\n",argvec[0],strerror(errno));
       exit(0);
     }
    if ((npoll < MAXPEND) && (pfds[npoll].revents & (POLLIN|POLLRDNORM|POLLERR|POLLHUP)))
#define RQLEN (sizeof(int) + sizeof(struct sockaddr_storage))
     { unsigned char buf[RQLEN];
       int al;
       struct sockaddr_storage ss;
       if (Read(hostname_fd,&buf[0],RQLEN) < 0) exit(0);
       bcopy(&buf[0],&al,sizeof(int));
       if ((al < 1) || (al > sizeof(ss)))
	{ fprintf(stderr,"hostname process: unreasonable length %d\n",al);
	  exit(1);
	}
       bcopy(&buf[sizeof(int)],&ss,al);
       socketpair(AF_UNIX,SOCK_STREAM,0,&p[0]);
       pend[npend++] = p[0];
       pid = fork();
       if (pid == 0)
	{ int gnirv;
	  int ilen;
	  unsigned char uclen;
	  char host[NI_MAXHOST];
	  struct iovec iov[4];
	  close(hostname_fd);
	  for (i=npend-1;i>=0;i--) close(pend[i]);
	  gnirv = getnameinfo((struct sockaddr *)&ss,al,&host[0],NI_MAXHOST,0,0,0);
	  if (gnirv)
	   { const char *s;
	     s = gai_strerror(gnirv);
	     sprintf(&host[0],"(%.*s)",NI_MAXHOST-3,s);
	   }
	  iov[0].iov_base = &al;
	  iov[0].iov_len = sizeof(int);
	  iov[1].iov_base = &ss;
	  iov[1].iov_len = sizeof(struct sockaddr_storage);
	  ilen = strlen(&host[0]);
	  uclen = (ilen > 255) ? 255 : ilen;
	  iov[2].iov_base = &uclen;
	  iov[2].iov_len = 1;
	  iov[3].iov_base = &host[0];
	  iov[3].iov_len = uclen;
	  writev(p[1],&iov[0],4);
	  exit(0);
	}
       close(p[1]);
     }
    for (i=npoll-1;i>=0;i--)
     { if (pfds[i].revents & (POLLIN|POLLRDNORM|POLLERR|POLLHUP))
#define PRESTRING ( sizeof(int) +			\
		    sizeof(struct sockaddr_storage) )
	{ unsigned char buf[PRESTRING+1+255];
#define SETERR(s) (buf[PRESTRING]=strlen(strcpy(&buf[PRESTRING+1],(s))))
	  if (Read(pend[i],&buf[0],PRESTRING+1) == 0)
	   { if (Read(pend[i],&buf[PRESTRING+1],buf[PRESTRING]) == 0)
	      { 
	      }
	     else
	      { SETERR("(error A)");
	      }
	   }
	  else
	   { SETERR("(error B)");
	   }
	  write(hostname_fd,&buf[0],PRESTRING+1+buf[PRESTRING]);
#undef SETERR
#undef PRESTRING
	  close(pend[i]);
	  pend[i] = -1;
	}
     }
  }
}

#endif