/* -*-C-*-
 Common library code for the GNU Emacs server and client.

 This file is part of GNU Emacs.

 Copying is permitted under those conditions described by the GNU
 General Public License.

 Copyright (C) 1989 Free Software Foundation, Inc.

 Author: Andy Norman (ange@hplb.hpl.hp.com), based on 
         'etc/server.c' and 'etc/emacsclient.c' from the 18.52 GNU
         Emacs distribution.

 Please mail bugs and suggestions to the author at the above address.
*/

/* HISTORY 
 * 11-Nov-1990		bristor@simba	
 *    Added EOT stuff.
 */

/*
 * This file incorporates new features added by Bob Weiner <weiner@mot.com>,
 * Darrell Kindred <dkindred@cmu.edu> and Arup Mukherjee <arup@cmu.edu>.
 * Please see the note at the end of the README file for details.
 *
 * (If gnuserv came bundled with your emacs, the README file is probably
 * ../etc/gnuserv.README relative to the directory containing this file)
 */

#if 0
static char rcsid [] = "!Header: gnuslib.c,v 2.4 95/02/16 11:57:37 arup alpha !";
#endif

#include "gnuserv.h"
#include <errno.h>

#ifdef SYSV_IPC
static int connect_to_ipc_server (void);
#endif
#ifdef UNIX_DOMAIN_SOCKETS
static int connect_to_unix_server (void);
#endif
#ifdef INTERNET_DOMAIN_SOCKETS
static int connect_to_internet_server (char *serverhost, unsigned short port);
#endif

/* On some systems, e.g. DGUX, inet_addr returns a 'struct in_addr'. */
#ifdef HAVE_BROKEN_INET_ADDR
# define IN_ADDR struct in_addr
# define NUMERIC_ADDR_ERROR (numeric_addr.s_addr == -1)
#else
# if (LONGBITS > 32)
#  define IN_ADDR unsigned int
# else
#  define IN_ADDR unsigned long
# endif
# define NUMERIC_ADDR_ERROR (numeric_addr == (IN_ADDR) -1)
#endif

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */

#include <arpa/inet.h>

char *tmpdir = NULL;

char *progname = NULL;

int
make_connection (char *hostarg, int portarg, int *s)
{
#ifdef INTERNET_DOMAIN_SOCKETS
  char *ptr;
  if (hostarg == NULL)
    hostarg = getenv("GNU_HOST");
  if (portarg == 0 && (ptr=getenv("GNU_PORT")) != NULL)
    portarg = atoi(ptr);
#endif

  if (hostarg != NULL) {
    /* hostname was given explicitly, via cmd line arg or GNU_HOST, 
     * so obey it. */
#ifdef UNIX_DOMAIN_SOCKETS
    if (!strcmp(hostarg, "unix")) {
      *s = connect_to_unix_server();
      return (int) CONN_UNIX;
    } 
#endif /* UNIX_DOMAIN_SOCKETS */
#ifdef INTERNET_DOMAIN_SOCKETS
    *s = connect_to_internet_server(hostarg, portarg);
    return (int) CONN_INTERNET;
#endif
#ifdef SYSV_IPC
    return -1;              /* hostarg should always be NULL for SYSV_IPC */
#endif
  } else {
    /* no hostname given.  Use unix-domain/sysv-ipc, or
     * internet-domain connection to local host if they're not available. */
#if   defined(UNIX_DOMAIN_SOCKETS)
    *s = connect_to_unix_server();
    return (int) CONN_UNIX;
#elif defined(SYSV_IPC)
    *s = connect_to_ipc_server();
    return (int) CONN_IPC;
#elif defined(INTERNET_DOMAIN_SOCKETS)
    {
      char localhost[HOSTNAMSZ];
      gethostname(localhost,HOSTNAMSZ);	  /* use this host by default */    
      *s = connect_to_internet_server(localhost, portarg);
      return (int) CONN_INTERNET;
    }
#endif /* IPC type */
  }
}

#ifdef SYSV_IPC
/*
  connect_to_ipc_server -- establish connection with server process via SYSV IPC
  			   Returns msqid for server if successful.
*/
static int
connect_to_ipc_server (void)
{
  int s;			/* connected msqid */
  key_t key;			/* message key */
  char buf[GSERV_BUFSZ+1];		/* buffer for filename */

  sprintf(buf,"%s/gsrv%d",tmpdir,(int)geteuid());
  creat(buf,0600);
  if ((key = ftok(buf,1)) == -1) {
    perror(progname);
    fprintf(stderr, "%s: unable to get ipc key from %s\n",
	    progname, buf);
    exit(1);
  }

  if ((s = msgget(key,0600)) == -1) {
    perror(progname);
    fprintf(stderr,"%s: unable to access msg queue\n",progname);
    exit(1);
  }; /* if */

  return(s);

} /* connect_to_ipc_server */


/*
  disconnect_from_ipc_server -- inform the server that sending has finished,
                                and wait for its reply.
*/
void
disconnect_from_ipc_server (int s, struct msgbuf *msgp, int echo)
{
  int len;			/* length of received message */

  send_string(s,EOT_STR);	/* EOT terminates this message */
  msgp->mtype = 1;

  if(msgsnd(s,msgp,strlen(msgp->mtext)+1,0) < 0) {
    perror(progname);
    fprintf(stderr,"%s: unable to send message to server\n",progname);
    exit(1);
  }; /* if */
  
  if((len = msgrcv(s,msgp,GSERV_BUFSZ,getpid(),0)) < 0) {
    perror(progname);
    fprintf(stderr,"%s: unable to receive message from server\n",progname);
    exit(1);
  }; /* if */

  if (echo) {
    msgp->mtext[len] = '\0';	/* string terminate message */
    fputs(msgp->mtext, stdout);
    if (msgp->mtext[len-1] != '\n') putchar ('\n');
  }; /* if */

} /* disconnect_from_ipc_server */  
#endif /* SYSV_IPC */


#if defined(INTERNET_DOMAIN_SOCKETS) || defined(UNIX_DOMAIN_SOCKETS)
/*
  send_string -- send string to socket.
*/
void
send_string (int s, const char *msg)
{
#if 0
  if (send(s,msg,strlen(msg),0) < 0) {
    perror(progname);
    fprintf(stderr,"%s: unable to send\n",progname);
    exit(1);
  }; /* if */ 
#else  
  int len, left=strlen(msg);
  while (left > 0) {
    if ((len=write(s,msg,min2(left,GSERV_BUFSZ))) < 0) {
       /* XEmacs addition: robertl@arnet.com */
       if (errno == EPIPE) {
 	return ;
       }
      perror(progname);
      fprintf(stderr,"%s: unable to send\n",progname);
      exit(1);
    }; /* if */
    left -= len;
    msg += len;
  }; /* while */ 
#endif
} /* send_string */

/*
  read_line -- read a \n terminated line from a socket
*/
int
read_line (int s, char *dest)
{
  int length;
  int offset=0;
  char buffer[GSERV_BUFSZ+1];

  while ((length=read(s,buffer+offset,1)>0) && buffer[offset]!='\n'
	 && buffer[offset] != EOT_CHR) {
    offset += length;
    if (offset >= GSERV_BUFSZ) 
      break;
  }
  buffer[offset] = '\0';
  strcpy(dest,buffer);
  return 1;
} /* read_line */
#endif /* INTERNET_DOMAIN_SOCKETS || UNIX_DOMAIN_SOCKETS */


#ifdef UNIX_DOMAIN_SOCKETS
/*
  connect_to_unix_server -- establish connection with server process via a unix-
  			    domain socket. Returns socket descriptor for server
			    if successful.
*/
static int
connect_to_unix_server (void)
{
  int s;			/* connected socket descriptor */
  struct sockaddr_un server; 	/* for unix connections */

  if ((s = socket(AF_UNIX,SOCK_STREAM,0)) < 0) {
    perror(progname);
    fprintf(stderr,"%s: unable to create socket\n",progname);
    exit(1);
  }; /* if */
  
  server.sun_family = AF_UNIX;
#ifdef HIDE_UNIX_SOCKET
  sprintf(server.sun_path,"%s/gsrvdir%d/gsrv",tmpdir,(int)geteuid());
#else  /* HIDE_UNIX_SOCKET */
  sprintf(server.sun_path,"%s/gsrv%d",tmpdir,(int)geteuid());
#endif /* HIDE_UNIX_SOCKET */
  if (connect(s,(struct sockaddr *)&server,strlen(server.sun_path)+2) < 0) {
    perror(progname);
    fprintf(stderr,"%s: unable to connect to local\n",progname);
    exit(1);
  }; /* if */

  return(s);

} /* connect_to_unix_server */
#endif /* UNIX_DOMAIN_SOCKETS */


#ifdef INTERNET_DOMAIN_SOCKETS
/*
  internet_addr -- return the internet addr of the hostname or
                   internet address passed. Return -1 on error.
*/
int
internet_addr (char *host)
{
  struct hostent *hp;		/* pointer to host info for remote host */
  IN_ADDR numeric_addr;		/* host address */

  numeric_addr = inet_addr(host);
  if (!NUMERIC_ADDR_ERROR)
    return numeric_addr;
  else if ((hp = gethostbyname(host)) != NULL)
    return ((struct in_addr *)(hp->h_addr))->s_addr;
  else
    return -1;

} /* internet_addr */

#ifdef AUTH_MAGIC_COOKIE
# include <X11/X.h>
# include <X11/Xauth.h>

static Xauth *server_xauth = NULL;
#endif

/*
  connect_to_internet_server -- establish connection with server process via 
  				an internet domain socket. Returns socket
				descriptor for server if successful.
*/
static int
connect_to_internet_server (char *serverhost, unsigned short port)
{
  int s;				/* connected socket descriptor */
  struct servent *sp;			/* pointer to service information */
  struct sockaddr_in peeraddr_in;	/* for peer socket address */
  char buf[512];                        /* temporary buffer */

  /* clear out address structures */
  memset((char *)&peeraddr_in,0,sizeof(struct sockaddr_in));
  
  /* Set up the peer address to which we will connect. */
  peeraddr_in.sin_family = AF_INET;

  /* look up the server host's internet address */
  if ((peeraddr_in.sin_addr.s_addr = internet_addr(serverhost)) == -1) {
    fprintf(stderr,"%s: unable to find %s in /etc/hosts or from YP\n",
	    progname,serverhost);
    exit(1);
  }; /* if */
  
  if (port == 0) {
    if ((sp = getservbyname ("gnuserv","tcp")) == NULL)
      peeraddr_in.sin_port = htons(DEFAULT_PORT+getuid());
    else
      peeraddr_in.sin_port = sp->s_port;
  } /* if */
  else
    peeraddr_in.sin_port = htons(port);
  
  /* Create the socket. */
  if ((s = socket (AF_INET,SOCK_STREAM, 0))== -1) {
    perror(progname);
    fprintf(stderr,"%s: unable to create socket\n",progname);
    exit(1);
  }; /* if */
  
  /* Try to connect to the remote server at the address
   * which was just built into peeraddr.
   */
  if (connect(s, (struct sockaddr *)&peeraddr_in,
	      sizeof(struct sockaddr_in)) == -1) {
    perror(progname);
    fprintf(stderr, "%s: unable to connect to remote\n",progname);
    exit(1);
  }; /* if */

#ifdef AUTH_MAGIC_COOKIE

  /* send credentials using MIT-MAGIC-COOKIE-1 protocol */
  
  server_xauth = 
    XauGetAuthByAddr(FamilyInternet, 
		     sizeof(peeraddr_in.sin_addr.s_addr), 
		     (char *) &peeraddr_in.sin_addr.s_addr,
		     strlen(MCOOKIE_SCREEN), MCOOKIE_SCREEN,
		     strlen(MCOOKIE_X_NAME), MCOOKIE_X_NAME);

  if (server_xauth && server_xauth->data) {
    sprintf(buf, "%s\n%d\n", MCOOKIE_NAME, server_xauth->data_length);
    write (s, buf, strlen(buf));
    write (s, server_xauth->data, server_xauth->data_length);

    return (s);
  }

#endif /* AUTH_MAGIC_COOKIE */

  sprintf (buf, "%s\n", DEFAUTH_NAME);
  write (s, buf, strlen(buf));

  return(s);

} /* connect_to_internet_server */
#endif /* INTERNET_DOMAIN_SOCKETS */


#if defined(INTERNET_DOMAIN_SOCKETS) || defined(UNIX_DOMAIN_SOCKETS)
/*
  disconnect_from_server -- inform the server that sending has finished, and wait for
                            its reply.
*/
void
disconnect_from_server (int s, int echo)
{
#if 0
  char buffer[REPLYSIZ+1];
#else
  char buffer[GSERV_BUFSZ+1];
#endif
  int add_newline = 1;
  int length;

  send_string(s,EOT_STR);		/* make sure server gets string */

#if !defined (linux)  && !defined (_SCO_DS) 
  /*
   * shutdown is completely hozed under linux. If s is a unix domain socket,
   * you'll get EOPNOTSUPP back from it. If s is an internet socket, you get
   * a broken pipe when you try to read a bit later. The latter
   * problem is fixed for linux versions >= 1.1.46, but the problem
   * with unix sockets persists. Sigh.
   */

  if (shutdown(s,1) == -1) {
     perror(progname);
     fprintf(stderr, "%s: unable to shutdown socket\n",progname);
     exit(1);
  }; /* if */
#endif

#if 0
  while((length = recv(s,buffer,REPLYSIZ,0)) > 0) {
    buffer[length] = '\0';
    if (echo) fputs(buffer,stdout);
    add_newline = (buffer[length-1] != '\n');
  }; /* while */
#else
  while ((length = read(s,buffer,GSERV_BUFSZ)) > 0 ||
      (length == -1 && errno == EINTR)) {
    if (length) {
      buffer[length] = '\0';
      if (echo) {
	fputs(buffer,stdout);
	add_newline = (buffer[length-1] != '\n');
      }; /* if */
    }; /* if */
  }; /* while */
#endif
  
  if (echo && add_newline) putchar('\n');

  if(length < 0) {
    perror(progname);
    fprintf(stderr,"%s: unable to read the reply from the server\n",progname);
    exit(1);
  }; /* if */

} /* disconnect_from_server */  
#endif /* INTERNET_DOMAIN_SOCKETS || UNIX_DOMAIN_SOCKETS */