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

#include "utils.h"
#include "ctype.h"
#include "externs.h"
#include "username.h"

extern char **argvec;

#define IDENTD_PORT 113

#if defined(USERNAMES)

#if !defined(SYNC_USERNAMES)
static
#endif
char *run_identd(const struct sockaddr *lcl, const struct sockaddr *rem, int sslen)
{
 int s;
 int r;
 char buf[10240];
 char *bp;
 int l;
 struct timeval end;
 struct timeval now;
 int ms;
 struct sockaddr_storage lss;
 struct sockaddr_storage rss;
 int slen;
 int lport;
 int rport;
 struct pollfd pfd;

 if (lcl->sa_family != rem->sa_family)
  { return(dup_string("(AFs differ)"));
  }
 switch (lcl->sa_family)
  { case AF_INET:
       if (sslen != sizeof(struct sockaddr_in)) return(dup_string("(AF_INET length wrong)"));
       lport = ntohs(((const struct sockaddr_in *)lcl)->sin_port);
       rport = ntohs(((const struct sockaddr_in *)rem)->sin_port);
       *((struct sockaddr_in *)&lss) = *(const struct sockaddr_in *)lcl;
       ((struct sockaddr_in *)&lss)->sin_port = 0;
       *((struct sockaddr_in *)&rss) = *(const struct sockaddr_in *)rem;
       ((struct sockaddr_in *)&rss)->sin_port = htons(IDENTD_PORT);
       slen = sizeof(struct sockaddr_in);
       break;
    case AF_INET6:
       if (sslen != sizeof(struct sockaddr_in6)) return(dup_string("(AF_INET6 length wrong)"));
       lport = ntohs(((const struct sockaddr_in6 *)lcl)->sin6_port);
       rport = ntohs(((const struct sockaddr_in6 *)rem)->sin6_port);
       *((struct sockaddr_in6 *)&lss) = *(const struct sockaddr_in6 *)lcl;
       ((struct sockaddr_in6 *)&lss)->sin6_port = 0;
       *((struct sockaddr_in6 *)&rss) = *(const struct sockaddr_in6 *)rem;
       ((struct sockaddr_in6 *)&rss)->sin6_port = htons(IDENTD_PORT);
       slen = sizeof(struct sockaddr_in6);
       break;
    default:
       return(dup_string("(unknown AF)"));
       break;
  }
 s = socket(lcl->sa_family,SOCK_STREAM,0);
 if (s < 0)
  { malprintf(&bp,"(socket: %s)",strerror(errno));
    return(bp);
  }
 if (bind(s,(struct sockaddr *)&lss,slen) < 0)
  { malprintf(&bp,"(bind: %s)",strerror(errno));
    close(s);
    return(bp);
  }
 if (connect(s,(struct sockaddr *)&rss,slen) < 0)
  { malprintf(&bp,"(connect: %s)",strerror(errno));
    close(s);
    return(bp);
  }
 snprintf(&buf[0],sizeof(buf),"%hu,%hu\r\n",rport,lport);
 write(s,&buf[0],strlen(&buf[0]));
 shutdown(s,1);
 bp = &buf[0];
 l = sizeof(buf) - 1;
 gettimeofday(&end,0);
 end.tv_sec += 60;
 while (l > 0)
  { pfd.fd = s;
    pfd.events = POLLIN | POLLRDNORM;
    gettimeofday(&now,0);
    if (now.tv_sec > end.tv_sec)
     { if (l < 16) bp -= 16;
       strcpy(bp,"(timeout)");
       close(s);
       return(dup_string(&buf[0]));
     }
    ms = ((end.tv_sec - now.tv_sec) * 1000) +
	 ((1000000 - now.tv_usec) / 1000);
    if (ms < 1) ms = 1;
    r = poll(&pfd,1,ms);
    if (r < 0)
     { if (errno == EINTR) continue;
       sprintf(&buf[0],"(poll: %s)",strerror(errno));
       close(s);
       return(dup_string(&buf[0]));
     }
    if ((r > 0) && (pfd.revents & (POLLIN|POLLRDNORM|POLLERR|POLLHUP)))
     { r = read(s,bp,l);
       if (r < 0)
	{ sprintf(&buf[0],"(read: %s)",strerror(errno));
	  close(s);
	  return(dup_string(&buf[0]));
	}
       if (r == 0) break;
       bp += r;
       l -= r;
     }
  }
 close(s);
 r = bp - &buf[0];
 if ((r > 0) && (bp[-1] == '\n'))
  { r --;
    bp --;
  }
 if ((r > 0) && (bp[-1] == '\r'))
  { r --;
    bp --;
  }
 l = bp - &buf[0];
 *bp = '\0';
 l = 0;
 for (bp=&buf[0];*bp;bp++)
  { if ( (*(unsigned char *)bp < 32) ||
	 ( (*(unsigned char *)bp >= 127) &&
	   (*(unsigned char *)bp < 160) ) )
     { l --;
     }
    else if (l != 0)
     { bp[l] = *bp;
     }
  }
 if (l != 0) bp[l] = '\0';
 l = (bp+l) - &buf[0];
 bp = index(&buf[0],':');
 if (! bp)
  { int i;
    fprintf(stderr,"no colon 1:");
    for (i=0;i<l;i++)
     { if (i > 32)
	{ fprintf(stderr," ...");
	  break;
	}
       fprintf(stderr," %02x",((unsigned char *)&buf[0])[i]);
     }
    fprintf(stderr,"\n");
    l = strlen(&buf[0]);
    if (l > 100) l = 100;
    bcopy(&buf[0],&buf[20],l);
    bcopy("(error: no colon 1: ",&buf[0],20);
    buf[l+20] = ')';
    buf[l+21] = '\0';
    return(dup_string(&buf[0]));
  }
 do bp++; while (*bp && Cisspace(*bp));
 if (!bcmp(bp,"USERID",6))
  { bp = index(bp+6,':');
    if (! bp) return(dup_string("(error: no colon after USERID)"));
    bp = index(bp+1,':');
    if (! bp) return(dup_string("(error: no colon after OS)"));
    return(bp+1);
  }
 else if (!bcmp(bp,"ERROR",5))
  { return(dup_string(bp));
  }
 return(dup_string("(error: neither USERID nor ERROR)"));
}

#endif

#if defined(USERNAMES) && !defined(SYNC_USERNAMES)

int username_fd;
int username_px;

void fork_username_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;

 socketpair(AF_UNIX,SOCK_STREAM,0,&p[0]);
 pid = fork();
 if (pid)
  { username_fd = p[0];
    close(p[1]);
    return;
  }
 signal(SIGINT,SIG_IGN);
 username_fd = p[1];
 close(p[0]);
 for (i=getdtablesize()-1;i>=0;i--)
  { if ((i != username_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 (npend < MAXPEND)
     { pfds[j].fd = username_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 [2]))
     { unsigned char rqbuf[RQLEN];
       struct sockaddr_storage ss[2];
       int sslen;
       if (Read(username_fd,&rqbuf[0],RQLEN) < 0) exit(0);
       bcopy(&rqbuf[0],&sslen,sizeof(int));
       bcopy(&rqbuf[sizeof(int)],&ss[0],sizeof(struct sockaddr_storage [2]));
       socketpair(AF_UNIX,SOCK_STREAM,0,&p[0]);
       pend[npend++] = p[0];
       pid = fork();
       if (pid == 0)
	{ char *s;
	  int n;
	  unsigned char len;
	  struct iovec iov[4];
	  close(username_fd);
	  for (i=npend-1;i>=0;i--) close(pend[i]);
	  s = run_identd((void *)&ss[0],(void *)&ss[1],sslen);
	  n = strlen(s);
	  len = (n > 255) ? 255 : n;
	  iov[0].iov_base = &sslen;
	  iov[0].iov_len = sizeof(sslen);
	  iov[1].iov_base = &ss[0];
	  iov[1].iov_len = sizeof(ss);
	  iov[2].iov_base = &len;
	  iov[2].iov_len = 1;
	  iov[3].iov_base = s;
	  iov[3].iov_len = len;
	  writev(p[1],&iov[0],4);
	  free(s);
	  exit(0);
	}
       close(p[1]);
     }
    for (i=npoll-1;i>=0;i--)
     { if (pfds[i].revents & (POLLIN|POLLRDNORM|POLLERR|POLLHUP))
#define SAS (sizeof(int) + sizeof(struct sockaddr_storage [2]))
	{ unsigned char buf[SAS+1+255];
	  if ( (Read(pend[i],&buf[0],SAS+1) == 0) &&
	       (Read(pend[i],&buf[SAS+1],buf[SAS]) == 0) )
	   { write(username_fd,&buf[0],SAS+1+buf[SAS]);
	   }
#undef SAS
	  close(pend[i]);
	  pend[i] = -1;
	}
     }
  }
}

#endif