#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/mman.h>
#include <signal.h>
#include <sys/wait.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <string.h>

#define SAMPLEPORT 3630
void print_inet_address(struct sockaddr_in *) ;

int *pres_count ;
int logfd ;

void write_log(char *clnt_name, char *log_msg)
  {
   char outbuff[256] ;
   int wrz ;
   wrz = sprintf(outbuff, "%-38s -- %s\n", clnt_name, log_msg) ;
   if (wrz > 0)
      (void) write(logfd, outbuff, wrz) ;
  }

void handle_child(int ignore_me)
  {
   pid_t chld_pid ;
   int chld_status ;
   char outbuff[80] ;

   chld_pid=wait(&chld_status) ;
   if (!WIFEXITED(chld_status))
      (void) sprintf(outbuff, "abnormal termination (pid=%d)", chld_pid) ;
   else
      (void) sprintf(outbuff, "normal exit (pid=%d)", chld_pid) ;
   write_log("", outbuff) ;
  }

void parse_inet_address(struct sockaddr_in *inet_ad, char *buff, int bsize)
  {
   struct hostent *hp; 
   char *cname, bigbuff[1024] ;
   int cport, wrsz ;

   hp = gethostbyaddr((char *)&inet_ad->sin_addr,
		      sizeof(struct in_addr), AF_INET) ;
   if (hp == (struct hostent *)NULL)
     cname = inet_ntoa(inet_ad->sin_addr) ;
   else
     cname = hp->h_name ;
   cport = ntohs(inet_ad->sin_port) ;
   wrsz = sprintf(bigbuff, "%s (%d)", cname, cport) ;
   if (wrsz <= 0)
      buff[0] = '\0' ;
   else if (wrsz < bsize)
      (void) memcpy(buff, bigbuff, wrsz+1) ;
   else {
      (void) memcpy(buff, bigbuff, bsize-1) ;
      buff[bsize] = '\0' ;
   }
  }

#define CLIENT_NAME_SIZE 39

void count_em(int sock_fd, struct sockaddr_in * clnt_addr)
  {
   int bufpos, bufsiz, numout, lastcr, cptr, j ;
   char buff[1024], outbuff[80], lastfew[21] ;
   char clnt_name[CLIENT_NAME_SIZE] ;
   parse_inet_address(clnt_addr, clnt_name, CLIENT_NAME_SIZE) ;
   (void) sprintf(outbuff, "connected (pid=%d)", getpid()) ;
   write_log(clnt_name, outbuff) ;
   while ((bufsiz=read(sock_fd, buff, 1024)) > 0) {
      lastcr = -1 ;
      for (bufpos=0; bufpos<bufsiz; ++bufpos) {
 	 if (buff[bufpos]=='\n') {
            (*pres_count)++ ;
	    cptr = bufpos-20 ;
	    if ( cptr <= lastcr )
	       cptr = lastcr+1 ;
	    for (j=0 ; cptr<bufpos; ++j, ++cptr) {
 	       if (isprint((int) buff[cptr]))
		  lastfew[j] = buff[cptr] ;
	       else
		  lastfew[j] = '#' ;
	    }
	    lastfew[j] = '\0' ;
	    (void) sprintf(outbuff, "received [%s]", lastfew) ;
	    write_log(clnt_name, outbuff) ;
	    numout = sprintf(outbuff, "%d\n", *pres_count) ;
	    if (write(sock_fd, outbuff, numout)<0) {
	      write_log(clnt_name, strerror(errno)) ;
	      exit(1) ;
	    }
	    lastcr = bufpos ;
	 }
      }
   }
   if (bufsiz<0) {
      write_log(clnt_name, strerror(errno)) ;
      exit(1) ;
   }
   write_log(clnt_name, "socket closed") ;
  }

main(int argc, char *argv[])
  {
   void *share_page ;
   int srendezvous, sio, clntsize ;
   struct sockaddr_in servsock, clntsock; 
   pid_t newpid ;

   share_page = mmap((void *)NULL, sizeof(int), PROT_WRITE|PROT_READ,
		     MAP_SHARED|MAP_ANONYMOUS, -1, (off_t) 0) ;

   if (share_page == (void *)-1) {
      perror("mmap") ;
      exit(1) ;
   }

   logfd = open("/usr/local/csci/363/lc.log", O_WRONLY|O_CREAT|O_TRUNC, 0666) ;
   if (logfd < 0) {
      perror("open /usr/local/csci/363/lc.log") ;
      exit(1) ;
   }

   (void) signal(SIGCHLD , handle_child) ;

   pres_count = (int *)share_page ;
   *pres_count = 0 ;

   srendezvous = socket(AF_INET, SOCK_STREAM, 0) ;

   servsock.sin_family = AF_INET ;
   servsock.sin_port = htons(SAMPLEPORT) ;
   servsock.sin_addr.s_addr = INADDR_ANY ;

   if (bind(srendezvous, (struct sockaddr *) &servsock,
	    sizeof(struct sockaddr_in)))
     {
      perror("bind") ;
      exit(1) ;
     }

   (void) listen(srendezvous, SOMAXCONN) ;

   while (1)
     {
      clntsize = sizeof(struct sockaddr_in) ;
      sio = accept(srendezvous, (struct sockaddr *)&clntsock, &clntsize) ;
      if (sio<0) {
	 if (errno == EINTR)
	    continue ;
	 write_log("", strerror(errno)) ;
	 perror("accept") ;
	 exit(1) ;
      }
      newpid = fork() ;
      if (newpid == 0) {
	 /* child process */
	 close(srendezvous) ;
 	 count_em(sio, &clntsock) ;
	 exit(0) ;
      } else if (newpid > 0) {
	 /* parent process */
	 close(sio) ;
      } else {
	 /* you better stop now ! */
	 write_log("", strerror(errno)) ;
	 perror("fork") ;
	 exit(1) ;
      }
     }
  }