process.c

/* Asynchronous subprocess control for GNU Emacs.
   Copyright (C) 1985, 86, 87, 88, 93, 94, 95, 96, 98, 1999,
      2001, 2002 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


#include <config.h>
#include <signal.h>

/* This file is split into two parts by the following preprocessor
   conditional.  The 'then' clause contains all of the support for
   asynchronous subprocesses.  The 'else' clause contains stub
   versions of some of the asynchronous subprocess routines that are
   often called elsewhere in Emacs, so we don't have to #ifdef the
   sections that call them.  */


#ifdef subprocesses

#include <stdio.h>
#include <errno.h>
#include <setjmp.h>
#include <sys/types.h>		/* some typedefs are used in sys/file.h */
#include <sys/file.h>
#include <sys/stat.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#if defined(WINDOWSNT) || defined(UNIX98_PTYS)
#include <stdlib.h>
#include <fcntl.h>
#endif /* not WINDOWSNT */

#ifdef HAVE_SOCKETS	/* TCP connection support, if kernel can do it */
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef NEED_NET_ERRNO_H
#include <net/errno.h>
#endif /* NEED_NET_ERRNO_H */

/* Are local (unix) sockets supported?  */
#if defined (HAVE_SYS_UN_H) && !defined (NO_SOCKETS_IN_FILE_SYSTEM)
#if !defined (AF_LOCAL) && defined (AF_UNIX)
#define AF_LOCAL AF_UNIX
#endif
#ifdef AF_LOCAL
#define HAVE_LOCAL_SOCKETS
#include <sys/un.h>
#endif
#endif
#endif /* HAVE_SOCKETS */

/* TERM is a poor-man's SLIP, used on GNU/Linux.  */
#ifdef TERM
#include <client.h>
#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
#define IN_ADDR unsigned long
#define NUMERIC_ADDR_ERROR (numeric_addr == -1)
#endif

#if defined(BSD_SYSTEM) || defined(STRIDE)
#include <sys/ioctl.h>
#if !defined (O_NDELAY) && defined (HAVE_PTYS) && !defined(USG5)
#include <fcntl.h>
#endif /* HAVE_PTYS and no O_NDELAY */
#endif /* BSD_SYSTEM || STRIDE */

#ifdef BROKEN_O_NONBLOCK
#undef O_NONBLOCK
#endif /* BROKEN_O_NONBLOCK */

#ifdef NEED_BSDTTY
#include <bsdtty.h>
#endif

#ifdef IRIS
#include <sys/sysmacros.h>	/* for "minor" */
#endif /* not IRIS */

#ifdef HAVE_SYS_WAIT
#include <sys/wait.h>
#endif

#include "systime.h"
#include "systty.h"

#include "lisp.h"
#include "window.h"
#include "buffer.h"
#include "charset.h"
#include "coding.h"
#include "process.h"
#include "termhooks.h"
#include "termopts.h"
#include "commands.h"
#include "keyboard.h"
#include "frame.h"
#include "blockinput.h"
#include "dispextern.h"
#include "composite.h"
#include "atimer.h"

Lisp_Object Qprocessp;
Lisp_Object Qrun, Qstop, Qsignal;
Lisp_Object Qopen, Qclosed, Qconnect, Qfailed, Qlisten;
Lisp_Object Qlocal, Qdatagram;
Lisp_Object QCname, QCbuffer, QChost, QCservice, QCtype;
Lisp_Object QClocal, QCremote, QCcoding;
Lisp_Object QCserver, QCnowait, QCnoquery, QCstop;
Lisp_Object QCsentinel, QClog, QCoptions, QCplist;
Lisp_Object Qlast_nonmenu_event;
/* QCfamily is declared and initialized in xfaces.c,
   QCfilter in keyboard.c.  */
extern Lisp_Object QCfamily, QCfilter;

/* Qexit is declared and initialized in eval.c.  */

/* QCfamily is defined in xfaces.c.  */
extern Lisp_Object QCfamily;
/* QCfilter is defined in keyboard.c.  */
extern Lisp_Object QCfilter;

/* a process object is a network connection when its childp field is neither
   Qt nor Qnil but is instead a property list (KEY VAL ...).  */

#ifdef HAVE_SOCKETS
#define NETCONN_P(p) (GC_CONSP (XPROCESS (p)->childp))
#define NETCONN1_P(p) (GC_CONSP ((p)->childp))
#else
#define NETCONN_P(p) 0
#define NETCONN1_P(p) 0
#endif /* HAVE_SOCKETS */

/* Define first descriptor number available for subprocesses.  */
#ifdef VMS
#define FIRST_PROC_DESC 1
#else /* Not VMS */
#define FIRST_PROC_DESC 3
#endif

/* Define SIGCHLD as an alias for SIGCLD.  There are many conditionals
   testing SIGCHLD.  */

#if !defined (SIGCHLD) && defined (SIGCLD)
#define SIGCHLD SIGCLD
#endif /* SIGCLD */

#include "syssignal.h"

#include "syswait.h"

extern void set_waiting_for_input P_ ((EMACS_TIME *));

#ifndef USE_CRT_DLL
extern int errno;
#endif
#ifdef VMS
extern char *sys_errlist[];
#endif

#ifndef HAVE_H_ERRNO
extern int h_errno;
#endif

/* t means use pty, nil means use a pipe,
   maybe other values to come.  */
static Lisp_Object Vprocess_connection_type;

#ifdef SKTPAIR
#ifndef HAVE_SOCKETS
#include <sys/socket.h>
#endif
#endif /* SKTPAIR */

/* These next two vars are non-static since sysdep.c uses them in the
   emulation of `select'.  */
/* Number of events of change of status of a process.  */
int process_tick;
/* Number of events for which the user or sentinel has been notified.  */
int update_tick;

/* Define NON_BLOCKING_CONNECT if we can support non-blocking connects.  */

#ifdef BROKEN_NON_BLOCKING_CONNECT
#undef NON_BLOCKING_CONNECT
#else
#ifndef NON_BLOCKING_CONNECT
#ifdef HAVE_SOCKETS
#ifdef HAVE_SELECT
#if defined (HAVE_GETPEERNAME) || defined (GNU_LINUX)
#if defined (O_NONBLOCK) || defined (O_NDELAY)
#if defined (EWOULDBLOCK) || defined (EINPROGRESS)
#define NON_BLOCKING_CONNECT
#endif /* EWOULDBLOCK || EINPROGRESS */
#endif /* O_NONBLOCK || O_NDELAY */
#endif /* HAVE_GETPEERNAME || GNU_LINUX */
#endif /* HAVE_SELECT */
#endif /* HAVE_SOCKETS */
#endif /* NON_BLOCKING_CONNECT */
#endif /* BROKEN_NON_BLOCKING_CONNECT */

/* Define DATAGRAM_SOCKETS if datagrams can be used safely on
   this system.  We need to read full packets, so we need a
   "non-destructive" select.  So we require either native select,
   or emulation of select using FIONREAD.  */

#ifdef BROKEN_DATAGRAM_SOCKETS
#undef DATAGRAM_SOCKETS
#else
#ifndef DATAGRAM_SOCKETS
#ifdef HAVE_SOCKETS
#if defined (HAVE_SELECT) || defined (FIONREAD)
#if defined (HAVE_SENDTO) && defined (HAVE_RECVFROM) && defined (EMSGSIZE)
#define DATAGRAM_SOCKETS
#endif /* HAVE_SENDTO && HAVE_RECVFROM && EMSGSIZE */
#endif /* HAVE_SELECT || FIONREAD */
#endif /* HAVE_SOCKETS */
#endif /* DATAGRAM_SOCKETS */
#endif /* BROKEN_DATAGRAM_SOCKETS */

#ifdef TERM
#undef NON_BLOCKING_CONNECT
#undef DATAGRAM_SOCKETS
#endif


#include "sysselect.h"

extern int keyboard_bit_set P_ ((SELECT_TYPE *));

/* If we support a window system, turn on the code to poll periodically
   to detect C-g.  It isn't actually used when doing interrupt input.  */
#ifdef HAVE_WINDOW_SYSTEM
#define POLL_FOR_INPUT
#endif

/* Mask of bits indicating the descriptors that we wait for input on.  */

static SELECT_TYPE input_wait_mask;

/* Mask that excludes keyboard input descriptor (s).  */

static SELECT_TYPE non_keyboard_wait_mask;

/* Mask that excludes process input descriptor (s).  */

static SELECT_TYPE non_process_wait_mask;

/* Mask of bits indicating the descriptors that we wait for connect to
   complete on.  Once they complete, they are removed from this mask
   and added to the input_wait_mask and non_keyboard_wait_mask.  */

static SELECT_TYPE connect_wait_mask;

/* Number of bits set in connect_wait_mask.  */
static int num_pending_connects;

/* The largest descriptor currently in use for a process object.  */
static int max_process_desc;

/* The largest descriptor currently in use for keyboard input.  */
static int max_keyboard_desc;

/* Nonzero means delete a process right away if it exits.  */
static int delete_exited_processes;

/* Indexed by descriptor, gives the process (if any) for that descriptor */
Lisp_Object chan_process[MAXDESC];

/* Alist of elements (NAME . PROCESS) */
Lisp_Object Vprocess_alist;

/* Buffered-ahead input char from process, indexed by channel.
   -1 means empty (no char is buffered).
   Used on sys V where the only way to tell if there is any
   output from the process is to read at least one char.
   Always -1 on systems that support FIONREAD.  */

/* Don't make static; need to access externally.  */
int proc_buffered_char[MAXDESC];

/* Table of `struct coding-system' for each process.  */
static struct coding_system *proc_decode_coding_system[MAXDESC];
static struct coding_system *proc_encode_coding_system[MAXDESC];

#ifdef DATAGRAM_SOCKETS
/* Table of `partner address' for datagram sockets.  */
struct sockaddr_and_len {
  struct sockaddr *sa;
  int len;
} datagram_address[MAXDESC];
#define DATAGRAM_CHAN_P(chan)	(datagram_address[chan].sa != 0)
#define DATAGRAM_CONN_P(proc)	(PROCESSP (proc) && datagram_address[XINT (XPROCESS (proc)->infd)].sa != 0)
#else
#define DATAGRAM_CHAN_P(chan)	(0)
#define DATAGRAM_CONN_P(proc)	(0)
#endif

static Lisp_Object get_process ();
static void exec_sentinel ();

extern EMACS_TIME timer_check ();
extern int timers_run;

/* Maximum number of bytes to send to a pty without an eof.  */
static int pty_max_bytes;

extern Lisp_Object Vfile_name_coding_system, Vdefault_file_name_coding_system;

#ifdef HAVE_PTYS
#ifdef HAVE_PTY_H
#include <pty.h>
#endif
/* The file name of the pty opened by allocate_pty.  */

static char pty_name[24];
#endif

/* Compute the Lisp form of the process status, p->status, from
   the numeric status that was returned by `wait'.  */

Lisp_Object status_convert ();

void
update_status (p)
     struct Lisp_Process *p;
{
  union { int i; WAITTYPE wt; } u;
  u.i = XFASTINT (p->raw_status_low) + (XFASTINT (p->raw_status_high) << 16);
  p->status = status_convert (u.wt);
  p->raw_status_low = Qnil;
  p->raw_status_high = Qnil;
}

/*  Convert a process status word in Unix format to
    the list that we use internally.  */

Lisp_Object
status_convert (w)
     WAITTYPE w;
{
  if (WIFSTOPPED (w))
    return Fcons (Qstop, Fcons (make_number (WSTOPSIG (w)), Qnil));
  else if (WIFEXITED (w))
    return Fcons (Qexit, Fcons (make_number (WRETCODE (w)),
				WCOREDUMP (w) ? Qt : Qnil));
  else if (WIFSIGNALED (w))
    return Fcons (Qsignal, Fcons (make_number (WTERMSIG (w)),
				  WCOREDUMP (w) ? Qt : Qnil));
  else
    return Qrun;
}

/* Given a status-list, extract the three pieces of information
   and store them individually through the three pointers.  */

void
decode_status (l, symbol, code, coredump)
     Lisp_Object l;
     Lisp_Object *symbol;
     int *code;
     int *coredump;
{
  Lisp_Object tem;

  if (SYMBOLP (l))
    {
      *symbol = l;
      *code = 0;
      *coredump = 0;
    }
  else
    {
      *symbol = XCAR (l);
      tem = XCDR (l);
      *code = XFASTINT (XCAR (tem));
      tem = XCDR (tem);
      *coredump = !NILP (tem);
    }
}

/* Return a string describing a process status list.  */

Lisp_Object
status_message (status)
     Lisp_Object status;
{
  Lisp_Object symbol;
  int code, coredump;
  Lisp_Object string, string2;

  decode_status (status, &symbol, &code, &coredump);

  if (EQ (symbol, Qsignal) || EQ (symbol, Qstop))
    {
      char *signame;
      synchronize_system_messages_locale ();
      signame = strsignal (code);
      if (signame == 0)
	signame = "unknown";
      string = build_string (signame);
      string2 = build_string (coredump ? " (core dumped)\n" : "\n");
      SSET (string, 0, DOWNCASE (SREF (string, 0)));
      return concat2 (string, string2);
    }
  else if (EQ (symbol, Qexit))
    {
      if (code == 0)
	return build_string ("finished\n");
      string = Fnumber_to_string (make_number (code));
      string2 = build_string (coredump ? " (core dumped)\n" : "\n");
      return concat3 (build_string ("exited abnormally with code "),
		      string, string2);
    }
  else if (EQ (symbol, Qfailed))
    {
      string = Fnumber_to_string (make_number (code));
      string2 = build_string ("\n");
      return concat3 (build_string ("failed with code "),
		      string, string2);
    }
  else
    return Fcopy_sequence (Fsymbol_name (symbol));
}

#ifdef HAVE_PTYS

/* Open an available pty, returning a file descriptor.
   Return -1 on failure.
   The file name of the terminal corresponding to the pty
   is left in the variable pty_name.  */

int
allocate_pty ()
{
  struct stat stb;
  register int c, i;
  int fd;

  /* Some systems name their pseudoterminals so that there are gaps in
     the usual sequence - for example, on HP9000/S700 systems, there
     are no pseudoterminals with names ending in 'f'.  So we wait for
     three failures in a row before deciding that we've reached the
     end of the ptys.  */
  int failed_count = 0;

#ifdef PTY_ITERATION
  PTY_ITERATION
#else
  for (c = FIRST_PTY_LETTER; c <= 'z'; c++)
    for (i = 0; i < 16; i++)
#endif
      {
#ifdef PTY_NAME_SPRINTF
	PTY_NAME_SPRINTF
#else
	sprintf (pty_name, "/dev/pty%c%x", c, i);
#endif /* no PTY_NAME_SPRINTF */

#ifdef PTY_OPEN
	PTY_OPEN;
#else /* no PTY_OPEN */
#ifdef IRIS
	/* Unusual IRIS code */
 	*ptyv = emacs_open ("/dev/ptc", O_RDWR | O_NDELAY, 0);
 	if (fd < 0)
 	  return -1;
	if (fstat (fd, &stb) < 0)
	  return -1;
#else /* not IRIS */
	if (stat (pty_name, &stb) < 0)
	  {
	    failed_count++;
	    if (failed_count >= 3)
	      return -1;
	  }
	else
	  failed_count = 0;
#ifdef O_NONBLOCK
	fd = emacs_open (pty_name, O_RDWR | O_NONBLOCK, 0);
#else
	fd = emacs_open (pty_name, O_RDWR | O_NDELAY, 0);
#endif
#endif /* not IRIS */
#endif /* no PTY_OPEN */

	if (fd >= 0)
	  {
	    /* check to make certain that both sides are available
	       this avoids a nasty yet stupid bug in rlogins */
#ifdef PTY_TTY_NAME_SPRINTF
	    PTY_TTY_NAME_SPRINTF
#else
            sprintf (pty_name, "/dev/tty%c%x", c, i);
#endif /* no PTY_TTY_NAME_SPRINTF */
#ifndef UNIPLUS
	    if (access (pty_name, 6) != 0)
	      {
		emacs_close (fd);
#if !defined(IRIS) && !defined(__sgi)
		continue;
#else
		return -1;
#endif /* IRIS */
	      }
#endif /* not UNIPLUS */
	    setup_pty (fd);
	    return fd;
	  }
      }
  return -1;
}
#endif /* HAVE_PTYS */

Lisp_Object
make_process (name)
     Lisp_Object name;
{
  register Lisp_Object val, tem, name1;
  register struct Lisp_Process *p;
  char suffix[10];
  register int i;

  p = allocate_process ();

  XSETINT (p->infd, -1);
  XSETINT (p->outfd, -1);
  XSETFASTINT (p->pid, 0);
  XSETFASTINT (p->tick, 0);
  XSETFASTINT (p->update_tick, 0);
  p->raw_status_low = Qnil;
  p->raw_status_high = Qnil;
  p->status = Qrun;
  p->mark = Fmake_marker ();

  /* If name is already in use, modify it until it is unused.  */

  name1 = name;
  for (i = 1; ; i++)
    {
      tem = Fget_process (name1);
      if (NILP (tem)) break;
      sprintf (suffix, "<%d>", i);
      name1 = concat2 (name, build_string (suffix));
    }
  name = name1;
  p->name = name;
  XSETPROCESS (val, p);
  Vprocess_alist = Fcons (Fcons (name, val), Vprocess_alist);
  return val;
}

void
remove_process (proc)
     register Lisp_Object proc;
{
  register Lisp_Object pair;

  pair = Frassq (proc, Vprocess_alist);
  Vprocess_alist = Fdelq (pair, Vprocess_alist);

  deactivate_process (proc);
}

DEFUN ("processp", Fprocessp, Sprocessp, 1, 1, 0,
       doc: /* Return t if OBJECT is a process.  */)
     (object)
     Lisp_Object object;
{
  return PROCESSP (object) ? Qt : Qnil;
}

DEFUN ("get-process", Fget_process, Sget_process, 1, 1, 0,
       doc: /* Return the process named NAME, or nil if there is none.  */)
     (name)
     register Lisp_Object name;
{
  if (PROCESSP (name))
    return name;
  CHECK_STRING (name);
  return Fcdr (Fassoc (name, Vprocess_alist));
}

DEFUN ("get-buffer-process", Fget_buffer_process, Sget_buffer_process, 1, 1, 0,
       doc: /* Return the (or a) process associated with BUFFER.
BUFFER may be a buffer or the name of one.  */)
     (buffer)
     register Lisp_Object buffer;
{
  register Lisp_Object buf, tail, proc;

  if (NILP (buffer)) return Qnil;
  buf = Fget_buffer (buffer);
  if (NILP (buf)) return Qnil;

  for (tail = Vprocess_alist; !NILP (tail); tail = Fcdr (tail))
    {
      proc = Fcdr (Fcar (tail));
      if (PROCESSP (proc) && EQ (XPROCESS (proc)->buffer, buf))
	return proc;
    }
  return Qnil;
}

/* This is how commands for the user decode process arguments.  It
   accepts a process, a process name, a buffer, a buffer name, or nil.
   Buffers denote the first process in the buffer, and nil denotes the
   current buffer.  */

static Lisp_Object
get_process (name)
     register Lisp_Object name;
{
  register Lisp_Object proc, obj;
  if (STRINGP (name))
    {
      obj = Fget_process (name);
      if (NILP (obj))
	obj = Fget_buffer (name);
      if (NILP (obj))
	error ("Process %s does not exist", SDATA (name));
    }
  else if (NILP (name))
    obj = Fcurrent_buffer ();
  else
    obj = name;

  /* Now obj should be either a buffer object or a process object.
   */
  if (BUFFERP (obj))
    {
      proc = Fget_buffer_process (obj);
      if (NILP (proc))
	error ("Buffer %s has no process", SDATA (XBUFFER (obj)->name));
    }
  else
    {
      CHECK_PROCESS (obj);
      proc = obj;
    }
  return proc;
}

DEFUN ("delete-process", Fdelete_process, Sdelete_process, 1, 1, 0,
       doc: /* Delete PROCESS: kill it and forget about it immediately.
PROCESS may be a process, a buffer, the name of a process or buffer, or
nil, indicating the current buffer's process.  */)
     (process)
     register Lisp_Object process;
{
  process = get_process (process);
  XPROCESS (process)->raw_status_low = Qnil;
  XPROCESS (process)->raw_status_high = Qnil;
  if (NETCONN_P (process))
    {
      XPROCESS (process)->status = Fcons (Qexit, Fcons (make_number (0), Qnil));
      XSETINT (XPROCESS (process)->tick, ++process_tick);
    }
  else if (XINT (XPROCESS (process)->infd) >= 0)
    {
      Fkill_process (process, Qnil);
      /* Do this now, since remove_process will make sigchld_handler do nothing.  */
      XPROCESS (process)->status
	= Fcons (Qsignal, Fcons (make_number (SIGKILL), Qnil));
      XSETINT (XPROCESS (process)->tick, ++process_tick);
      status_notify ();
    }
  remove_process (process);
  return Qnil;
}

DEFUN ("process-status", Fprocess_status, Sprocess_status, 1, 1, 0,
       doc: /* Return the status of PROCESS.
The returned value is one of the following symbols:
run  -- for a process that is running.
stop -- for a process stopped but continuable.
exit -- for a process that has exited.
signal -- for a process that has got a fatal signal.
open -- for a network stream connection that is open.
listen -- for a network stream server that is listening.
closed -- for a network stream connection that is closed.
connect -- when waiting for a non-blocking connection to complete.
failed -- when a non-blocking connection has failed.
nil -- if arg is a process name and no such process exists.
PROCESS may be a process, a buffer, the name of a process, or
nil, indicating the current buffer's process.  */)
     (process)
     register Lisp_Object process;
{
  register struct Lisp_Process *p;
  register Lisp_Object status;

  if (STRINGP (process))
    process = Fget_process (process);
  else
    process = get_process (process);

  if (NILP (process))
    return process;

  p = XPROCESS (process);
  if (!NILP (p->raw_status_low))
    update_status (p);
  status = p->status;
  if (CONSP (status))
    status = XCAR (status);
  if (NETCONN1_P (p))
    {
      if (EQ (status, Qexit))
	status = Qclosed;
      else if (EQ (p->command, Qt))
	status = Qstop;
      else if (EQ (status, Qrun))
	status = Qopen;
    }
  return status;
}

DEFUN ("process-exit-status", Fprocess_exit_status, Sprocess_exit_status,
       1, 1, 0,
       doc: /* Return the exit status of PROCESS or the signal number that killed it.
If PROCESS has not yet exited or died, return 0.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  if (!NILP (XPROCESS (process)->raw_status_low))
    update_status (XPROCESS (process));
  if (CONSP (XPROCESS (process)->status))
    return XCAR (XCDR (XPROCESS (process)->status));
  return make_number (0);
}

DEFUN ("process-id", Fprocess_id, Sprocess_id, 1, 1, 0,
       doc: /* Return the process id of PROCESS.
This is the pid of the Unix process which PROCESS uses or talks to.
For a network connection, this value is nil.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->pid;
}

DEFUN ("process-name", Fprocess_name, Sprocess_name, 1, 1, 0,
       doc: /* Return the name of PROCESS, as a string.
This is the name of the program invoked in PROCESS,
possibly modified to make it unique among process names.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->name;
}

DEFUN ("process-command", Fprocess_command, Sprocess_command, 1, 1, 0,
       doc: /* Return the command that was executed to start PROCESS.
This is a list of strings, the first string being the program executed
and the rest of the strings being the arguments given to it.
For a non-child channel, this is nil.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->command;
}

DEFUN ("process-tty-name", Fprocess_tty_name, Sprocess_tty_name, 1, 1, 0,
       doc: /* Return the name of the terminal PROCESS uses, or nil if none.
This is the terminal that the process itself reads and writes on,
not the name of the pty that Emacs uses to talk with that terminal.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->tty_name;
}

DEFUN ("set-process-buffer", Fset_process_buffer, Sset_process_buffer,
       2, 2, 0,
       doc: /* Set buffer associated with PROCESS to BUFFER (a buffer, or nil).  */)
     (process, buffer)
     register Lisp_Object process, buffer;
{
  struct Lisp_Process *p;

  CHECK_PROCESS (process);
  if (!NILP (buffer))
    CHECK_BUFFER (buffer);
  p = XPROCESS (process);
  p->buffer = buffer;
  if (NETCONN1_P (p))
    p->childp = Fplist_put (p->childp, QCbuffer, buffer);
  return buffer;
}

DEFUN ("process-buffer", Fprocess_buffer, Sprocess_buffer,
       1, 1, 0,
       doc: /* Return the buffer PROCESS is associated with.
Output from PROCESS is inserted in this buffer unless PROCESS has a filter.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->buffer;
}

DEFUN ("process-mark", Fprocess_mark, Sprocess_mark,
       1, 1, 0,
       doc: /* Return the marker for the end of the last output from PROCESS.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->mark;
}

DEFUN ("set-process-filter", Fset_process_filter, Sset_process_filter,
       2, 2, 0,
       doc: /* Give PROCESS the filter function FILTER; nil means no filter.
t means stop accepting output from the process.

When a process has a filter, its buffer is not used for output.
Instead, each time it does output, the entire string of output is
passed to the filter.

The filter gets two arguments: the process and the string of output.
The string argument is normally a multibyte string, except:
- if the process' input coding system is no-conversion or raw-text,
  it is a unibyte string (the non-converted input), or else
- if `default-enable-multibyte-characters' is nil, it is a unibyte
  string (the result of converting the decoded input multibyte
  string to unibyte with `string-make-unibyte').  */)
     (process, filter)
     register Lisp_Object process, filter;
{
  struct Lisp_Process *p;

  CHECK_PROCESS (process);
  p = XPROCESS (process);

  /* Don't signal an error if the process' input file descriptor
     is closed.  This could make debugging Lisp more difficult,
     for example when doing something like

     (setq process (start-process ...))
     (debug)
     (set-process-filter process ...)  */

  if (XINT (p->infd) >= 0)
    {
      if (EQ (filter, Qt) && !EQ (p->status, Qlisten))
	{
	  FD_CLR (XINT (p->infd), &input_wait_mask);
	  FD_CLR (XINT (p->infd), &non_keyboard_wait_mask);
	}
      else if (EQ (p->filter, Qt)
	       && !EQ (p->command, Qt)) /* Network process not stopped. */
	{
	  FD_SET (XINT (p->infd), &input_wait_mask);
	  FD_SET (XINT (p->infd), &non_keyboard_wait_mask);
	}
    }

  p->filter = filter;
  if (NETCONN1_P (p))
    p->childp = Fplist_put (p->childp, QCfilter, filter);
  return filter;
}

DEFUN ("process-filter", Fprocess_filter, Sprocess_filter,
       1, 1, 0,
       doc: /* Returns the filter function of PROCESS; nil if none.
See `set-process-filter' for more info on filter functions.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->filter;
}

DEFUN ("set-process-sentinel", Fset_process_sentinel, Sset_process_sentinel,
       2, 2, 0,
       doc: /* Give PROCESS the sentinel SENTINEL; nil for none.
The sentinel is called as a function when the process changes state.
It gets two arguments: the process, and a string describing the change.  */)
     (process, sentinel)
     register Lisp_Object process, sentinel;
{
  CHECK_PROCESS (process);
  XPROCESS (process)->sentinel = sentinel;
  return sentinel;
}

DEFUN ("process-sentinel", Fprocess_sentinel, Sprocess_sentinel,
       1, 1, 0,
       doc: /* Return the sentinel of PROCESS; nil if none.
See `set-process-sentinel' for more info on sentinels.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->sentinel;
}

DEFUN ("set-process-window-size", Fset_process_window_size,
       Sset_process_window_size, 3, 3, 0,
       doc: /* Tell PROCESS that it has logical window size HEIGHT and WIDTH.  */)
     (process, height, width)
     register Lisp_Object process, height, width;
{
  CHECK_PROCESS (process);
  CHECK_NATNUM (height);
  CHECK_NATNUM (width);

  if (XINT (XPROCESS (process)->infd) < 0
      || set_window_size (XINT (XPROCESS (process)->infd),
			  XINT (height), XINT (width)) <= 0)
    return Qnil;
  else
    return Qt;
}

DEFUN ("set-process-inherit-coding-system-flag",
       Fset_process_inherit_coding_system_flag,
       Sset_process_inherit_coding_system_flag, 2, 2, 0,
       doc: /* Determine whether buffer of PROCESS will inherit coding-system.
If the second argument FLAG is non-nil, then the variable
`buffer-file-coding-system' of the buffer associated with PROCESS
will be bound to the value of the coding system used to decode
the process output.

This is useful when the coding system specified for the process buffer
leaves either the character code conversion or the end-of-line conversion
unspecified, or if the coding system used to decode the process output
is more appropriate for saving the process buffer.

Binding the variable `inherit-process-coding-system' to non-nil before
starting the process is an alternative way of setting the inherit flag
for the process which will run.  */)
     (process, flag)
     register Lisp_Object process, flag;
{
  CHECK_PROCESS (process);
  XPROCESS (process)->inherit_coding_system_flag = flag;
  return flag;
}

DEFUN ("process-inherit-coding-system-flag",
       Fprocess_inherit_coding_system_flag, Sprocess_inherit_coding_system_flag,
       1, 1, 0,
       doc: /* Return the value of inherit-coding-system flag for PROCESS.
If this flag is t, `buffer-file-coding-system' of the buffer
associated with PROCESS will inherit the coding system used to decode
the process output.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->inherit_coding_system_flag;
}

DEFUN ("set-process-query-on-exit-flag",
       Fset_process_query_on_exit_flag, Sset_process_query_on_exit_flag,
       2, 2, 0,
       doc: /* Specify if query is needed for PROCESS when Emacs is exited.
If the second argument FLAG is non-nil, emacs will query the user before
exiting if PROCESS is running.  */)
     (process, flag)
     register Lisp_Object process, flag;
{
  CHECK_PROCESS (process);
  XPROCESS (process)->kill_without_query = Fnull (flag);
  return flag;
}

DEFUN ("process-query-on-exit-flag",
       Fprocess_query_on_exit_flag, Sprocess_query_on_exit_flag,
       1, 1, 0,
       doc: /* Return the current value of query on exit flag for PROCESS.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return Fnull (XPROCESS (process)->kill_without_query);
}

#ifdef DATAGRAM_SOCKETS
Lisp_Object Fprocess_datagram_address ();
#endif

DEFUN ("process-contact", Fprocess_contact, Sprocess_contact,
       1, 2, 0,
       doc: /* Return the contact info of PROCESS; t for a real child.
For a net connection, the value depends on the optional KEY arg.
If KEY is nil, value is a cons cell of the form (HOST SERVICE),
if KEY is t, the complete contact information for the connection is
returned, else the specific value for the keyword KEY is returned.
See `make-network-process' for a list of keywords.  */)
     (process, key)
     register Lisp_Object process, key;
{
  Lisp_Object contact;

  CHECK_PROCESS (process);
  contact = XPROCESS (process)->childp;

#ifdef DATAGRAM_SOCKETS
  if (DATAGRAM_CONN_P (process)
      && (EQ (key, Qt) || EQ (key, QCremote)))
    contact = Fplist_put (contact, QCremote,
			  Fprocess_datagram_address (process));
#endif

  if (!NETCONN_P (process) || EQ (key, Qt))
    return contact;
  if (NILP (key))
    return Fcons (Fplist_get (contact, QChost),
		  Fcons (Fplist_get (contact, QCservice), Qnil));
  return Fplist_get (contact, key);
}

DEFUN ("process-plist", Fprocess_plist, Sprocess_plist,
       1, 1, 0,
       doc: /* Return the plist of PROCESS.  */)
     (process)
     register Lisp_Object process;
{
  CHECK_PROCESS (process);
  return XPROCESS (process)->plist;
}