Retrospective commit from 2009-12-26.

[emacs.git] / src / sysdep.c

/* Interfaces to system-dependent kernel and library entries.
   Copyright (C) 1985, 1986, 1987, 1988, 1993, 1994, 1995, 1999, 2000, 2001,
                 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
                 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 3 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <ctype.h>
#include <signal.h>
#include <stdio.h>
#include <setjmp.h>
#ifdef HAVE_PWD_H
#include <pwd.h>
#include <grp.h>
#endif /* HAVE_PWD_H */
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif /* HAVE_LIMITS_H */
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_ALLOCA_H
#include <alloca.h>
#endif /* HAVE_ALLOCA_H */

#include "lisp.h"
/* Including stdlib.h isn't necessarily enough to get srandom
   declared, e.g. without __USE_XOPEN_EXTENDED with glibc 2.  */

/* The w32 build defines select stuff in w32.h, which is included by
   sys/select.h (included below).   */
#ifndef WINDOWSNT
#include "sysselect.h"
#endif

#include "blockinput.h"

#ifdef WINDOWSNT
#define read sys_read
#define write sys_write
#include <windows.h>
#ifndef NULL
#define NULL 0
#endif
#endif /* not WINDOWSNT */

/* Does anyone other than VMS need this? */
#ifndef fwrite
#define sys_fwrite fwrite
#else
#undef fwrite
#endif

#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>

#ifdef HAVE_SETPGID
#if !defined (USG) || defined (BSD_PGRPS)
#undef setpgrp
#define setpgrp setpgid
#endif
#endif

/* Get SI_SRPC_DOMAIN, if it is available.  */
#ifdef HAVE_SYS_SYSTEMINFO_H
#include <sys/systeminfo.h>
#endif

#ifdef MSDOS    /* Demacs 1.1.2 91/10/20 Manabu Higashida, MW Aug 1993 */
#include <dos.h>
#include "dosfns.h"
#include "msdos.h"
#include <sys/param.h>

#if __DJGPP__ > 1
extern int etext;
extern unsigned start __asm__ ("start");
#endif
#endif

#ifndef USE_CRT_DLL
#ifndef errno
extern int errno;
#endif
#endif

#include <sys/file.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#ifndef MSDOS
#include <sys/ioctl.h>
#endif

#include "systty.h"
#include "syswait.h"

#if defined (USG)
#include <sys/utsname.h>
#include <memory.h>
#endif /* USG */

extern int quit_char;

#include "keyboard.h"
#include "frame.h"
#include "window.h"
#include "termhooks.h"
#include "termchar.h"
#include "termopts.h"
#include "dispextern.h"
#include "process.h"
#include "cm.h"  /* for reset_sys_modes */

/* For serial_configure and serial_open.  */
extern Lisp_Object QCport, QCspeed, QCprocess;
extern Lisp_Object QCbytesize, QCstopbits, QCparity, Qodd, Qeven;
extern Lisp_Object QCflowcontrol, Qhw, Qsw, QCsummary;

#ifdef WINDOWSNT
#include <direct.h>
/* In process.h which conflicts with the local copy.  */
#define _P_WAIT 0
int _cdecl _spawnlp (int, const char *, const char *, ...);
int _cdecl _getpid (void);
extern char *getwd (char *);
#endif

#include "syssignal.h"
#include "systime.h"
#ifdef HAVE_UTIME_H
#include <utime.h>
#endif

#ifndef HAVE_UTIMES
#ifndef HAVE_STRUCT_UTIMBUF
/* We want to use utime rather than utimes, but we couldn't find the
   structure declaration.  We'll use the traditional one.  */
struct utimbuf {
  long actime;
  long modtime;
};
#endif
#endif

/* LPASS8 is new in 4.3, and makes cbreak mode provide all 8 bits.  */
#ifndef LPASS8
#define LPASS8 0
#endif

static const int baud_convert[] =
  {
    0, 50, 75, 110, 135, 150, 200, 300, 600, 1200,
    1800, 2400, 4800, 9600, 19200, 38400
  };

#ifdef HAVE_SPEED_T
#include <termios.h>
#else
#if defined (HAVE_LIBNCURSES) && ! defined (NCURSES_OSPEED_T)
#else
#if defined (HAVE_TERMIOS_H) && defined (GNU_LINUX)
#include <termios.h>
#endif
#endif
#endif

int emacs_ospeed;

void croak P_ ((char *)) NO_RETURN;

/* Temporary used by `sigblock' when defined in terms of signprocmask.  */

SIGMASKTYPE sigprocmask_set;


#if !defined (HAVE_GET_CURRENT_DIR_NAME) || defined (BROKEN_GET_CURRENT_DIR_NAME)

/* Return the current working directory.  Returns NULL on errors.
   Any other returned value must be freed with free. This is used
   only when get_current_dir_name is not defined on the system.  */
char*
get_current_dir_name ()
{
  char *buf;
  char *pwd;
  struct stat dotstat, pwdstat;
  /* If PWD is accurate, use it instead of calling getwd.  PWD is
     sometimes a nicer name, and using it may avoid a fatal error if a
     parent directory is searchable but not readable.  */
    if ((pwd = getenv ("PWD")) != 0
      && (IS_DIRECTORY_SEP (*pwd) || (*pwd && IS_DEVICE_SEP (pwd[1])))
      && stat (pwd, &pwdstat) == 0
      && stat (".", &dotstat) == 0
      && dotstat.st_ino == pwdstat.st_ino
      && dotstat.st_dev == pwdstat.st_dev
#ifdef MAXPATHLEN
      && strlen (pwd) < MAXPATHLEN
#endif
      )
    {
      buf = (char *) malloc (strlen (pwd) + 1);
      if (!buf)
        return NULL;
      strcpy (buf, pwd);
    }
#ifdef HAVE_GETCWD
  else
    {
      size_t buf_size = 1024;
      buf = (char *) malloc (buf_size);
      if (!buf)
        return NULL;
      for (;;)
        {
          if (getcwd (buf, buf_size) == buf)
            break;
          if (errno != ERANGE)
            {
              int tmp_errno = errno;
              free (buf);
              errno = tmp_errno;
              return NULL;
            }
          buf_size *= 2;
          buf = (char *) realloc (buf, buf_size);
          if (!buf)
            return NULL;
        }
    }
#else
  else
    {
      /* We need MAXPATHLEN here.  */
      buf = (char *) malloc (MAXPATHLEN + 1);
      if (!buf)
        return NULL;
      if (getwd (buf) == NULL)
        {
          int tmp_errno = errno;
          free (buf);
          errno = tmp_errno;
          return NULL;
        }
    }
#endif
  return buf;
}
#endif

\f
/* Discard pending input on all input descriptors.  */

void
discard_tty_input ()
{
#ifndef WINDOWSNT
  struct emacs_tty buf;

  if (noninteractive)
    return;

#ifdef MSDOS    /* Demacs 1.1.1 91/10/16 HIRANO Satoshi */
  while (dos_keyread () != -1)
    ;
#else /* not MSDOS */
  {
    struct tty_display_info *tty;
    for (tty = tty_list; tty; tty = tty->next)
      {
        if (tty->input)         /* Is the device suspended? */
          {
            EMACS_GET_TTY (fileno (tty->input), &buf);
            EMACS_SET_TTY (fileno (tty->input), &buf, 0);
          }
      }
  }
#endif /* not MSDOS */
#endif /* not WINDOWSNT */
}

\f
#ifdef SIGTSTP

/* Arrange for character C to be read as the next input from
   the terminal.
   XXX What if we have multiple ttys?
*/

void
stuff_char (char c)
{
  if (! FRAME_TERMCAP_P (SELECTED_FRAME ()))
    return;

/* Should perhaps error if in batch mode */
#ifdef TIOCSTI
  ioctl (fileno (CURTTY()->input), TIOCSTI, &c);
#else /* no TIOCSTI */
  error ("Cannot stuff terminal input characters in this version of Unix");
#endif /* no TIOCSTI */
}

#endif /* SIGTSTP */
\f
void
init_baud_rate (int fd)
{
  if (noninteractive)
    emacs_ospeed = 0;
  else
    {
#ifdef DOS_NT
    emacs_ospeed = 15;
#else  /* not DOS_NT */
#ifdef HAVE_TERMIOS
      struct termios sg;

      sg.c_cflag = B9600;
      tcgetattr (fd, &sg);
      emacs_ospeed = cfgetospeed (&sg);
#else /* not TERMIOS */
#ifdef HAVE_TERMIO
      struct termio sg;

      sg.c_cflag = B9600;
#ifdef HAVE_TCATTR
      tcgetattr (fd, &sg);
#else
      ioctl (fd, TCGETA, &sg);
#endif
      emacs_ospeed = sg.c_cflag & CBAUD;
#else /* neither TERMIOS nor TERMIO */
      struct sgttyb sg;

      sg.sg_ospeed = B9600;
      if (ioctl (fd, TIOCGETP, &sg) < 0)
        abort ();
      emacs_ospeed = sg.sg_ospeed;
#endif /* not HAVE_TERMIO */
#endif /* not HAVE_TERMIOS */
#endif /* not DOS_NT */
    }

  baud_rate = (emacs_ospeed < sizeof baud_convert / sizeof baud_convert[0]
               ? baud_convert[emacs_ospeed] : 9600);
  if (baud_rate == 0)
    baud_rate = 1200;
}

\f
/*ARGSUSED*/
void
set_exclusive_use (fd)
     int fd;
{
#ifdef FIOCLEX
  ioctl (fd, FIOCLEX, 0);
#endif
  /* Ok to do nothing if this feature does not exist */
}
\f
#ifndef subprocesses

wait_without_blocking ()
{
#ifdef BSD_SYSTEM
  wait3 (0, WNOHANG | WUNTRACED, 0);
#else
  croak ("wait_without_blocking");
#endif
  synch_process_alive = 0;
}

#endif /* not subprocesses */

int wait_debugging;   /* Set nonzero to make following function work under dbx
                         (at least for bsd).  */

SIGTYPE
wait_for_termination_signal ()
{}

/* Wait for subprocess with process id `pid' to terminate and
   make sure it will get eliminated (not remain forever as a zombie) */

void
wait_for_termination (pid)
     int pid;
{
  while (1)
    {
#ifdef subprocesses
#if defined (BSD_SYSTEM) || defined (HPUX)
      /* Note that kill returns -1 even if the process is just a zombie now.
         But inevitably a SIGCHLD interrupt should be generated
         and child_sig will do wait3 and make the process go away. */
      /* There is some indication that there is a bug involved with
         termination of subprocesses, perhaps involving a kernel bug too,
         but no idea what it is.  Just as a hunch we signal SIGCHLD to see
         if that causes the problem to go away or get worse.  */
      sigsetmask (sigmask (SIGCHLD));
      if (0 > kill (pid, 0))
        {
          sigsetmask (SIGEMPTYMASK);
          kill (getpid (), SIGCHLD);
          break;
        }
      if (wait_debugging)
        sleep (1);
      else
        sigpause (SIGEMPTYMASK);
#else /* not BSD_SYSTEM, and not HPUX version >= 6 */
#ifdef POSIX_SIGNALS    /* would this work for GNU/Linux as well? */
      sigblock (sigmask (SIGCHLD));
      errno = 0;
      if (kill (pid, 0) == -1 && errno == ESRCH)
        {
          sigunblock (sigmask (SIGCHLD));
          break;
        }

      sigsuspend (&empty_mask);
#else /* not POSIX_SIGNALS */
#ifdef HAVE_SYSV_SIGPAUSE
      sighold (SIGCHLD);
      if (0 > kill (pid, 0))
        {
          sigrelse (SIGCHLD);
          break;
        }
      sigpause (SIGCHLD);
#else /* not HAVE_SYSV_SIGPAUSE */
#ifdef WINDOWSNT
      wait (0);
      break;
#else /* not WINDOWSNT */
      if (0 > kill (pid, 0))
        break;
      /* Using sleep instead of pause avoids timing error.
         If the inferior dies just before the sleep,
         we lose just one second.  */
      sleep (1);
#endif /* not WINDOWSNT */
#endif /* not HAVE_SYSV_SIGPAUSE */
#endif /* not POSIX_SIGNALS */
#endif /* not BSD_SYSTEM, and not HPUX version >= 6 */
#else /* not subprocesses */
#if __DJGPP__ > 1
      break;
#else /* not __DJGPP__ > 1 */
      if (kill (pid, 0) < 0)
        break;
      wait (0);
#endif /* not __DJGPP__ > 1*/
#endif /* not subprocesses */
    }
}

#ifdef subprocesses

/*
 *      flush any pending output
 *      (may flush input as well; it does not matter the way we use it)
 */

void
flush_pending_output (channel)
     int channel;
{
#ifdef HAVE_TERMIOS
  /* If we try this, we get hit with SIGTTIN, because
     the child's tty belongs to the child's pgrp. */
#else
#ifdef TCFLSH
  ioctl (channel, TCFLSH, 1);
#else
#ifdef TIOCFLUSH
  int zero = 0;
  /* 3rd arg should be ignored
     but some 4.2 kernels actually want the address of an int
     and nonzero means something different.  */
  ioctl (channel, TIOCFLUSH, &zero);
#endif
#endif
#endif
}
\f
/*  Set up the terminal at the other end of a pseudo-terminal that
    we will be controlling an inferior through.
    It should not echo or do line-editing, since that is done
    in Emacs.  No padding needed for insertion into an Emacs buffer.  */

void
child_setup_tty (out)
     int out;
{
#ifndef DOS_NT
  struct emacs_tty s;

  EMACS_GET_TTY (out, &s);

#if defined (HAVE_TERMIO) || defined (HAVE_TERMIOS)
  s.main.c_oflag |= OPOST;      /* Enable output postprocessing */
  s.main.c_oflag &= ~ONLCR;     /* Disable map of NL to CR-NL on output */
#ifdef NLDLY
  /* http://lists.gnu.org/archive/html/emacs-devel/2008-05/msg00406.html
     Some versions of GNU Hurd do not have FFDLY?  */
#ifdef FFDLY
  s.main.c_oflag &= ~(NLDLY|CRDLY|TABDLY|BSDLY|VTDLY|FFDLY);
                                /* No output delays */
#else
  s.main.c_oflag &= ~(NLDLY|CRDLY|TABDLY|BSDLY|VTDLY);
                                /* No output delays */
#endif
#endif
  s.main.c_lflag &= ~ECHO;      /* Disable echo */
  s.main.c_lflag |= ISIG;       /* Enable signals */
#ifdef IUCLC
  s.main.c_iflag &= ~IUCLC;     /* Disable downcasing on input.  */
#endif
#ifdef ISTRIP
  s.main.c_iflag &= ~ISTRIP;    /* don't strip 8th bit on input */
#endif
#ifdef OLCUC
  s.main.c_oflag &= ~OLCUC;     /* Disable upcasing on output.  */
#endif
  s.main.c_oflag &= ~TAB3;      /* Disable tab expansion */
  s.main.c_cflag = (s.main.c_cflag & ~CSIZE) | CS8; /* Don't strip 8th bit */
  s.main.c_lflag |= ICANON;     /* Enable erase/kill and eof processing */
  s.main.c_cc[VEOF] = 04;       /* insure that EOF is Control-D */
  s.main.c_cc[VERASE] = CDISABLE;       /* disable erase processing */
  s.main.c_cc[VKILL] = CDISABLE;        /* disable kill processing */

#ifdef HPUX
  s.main.c_cflag = (s.main.c_cflag & ~CBAUD) | B9600; /* baud rate sanity */
#endif /* HPUX */

#ifdef SIGNALS_VIA_CHARACTERS
  /* the QUIT and INTR character are used in process_send_signal
     so set them here to something useful.  */
  if (s.main.c_cc[VQUIT] == CDISABLE)
    s.main.c_cc[VQUIT] = '\\'&037;      /* Control-\ */
  if (s.main.c_cc[VINTR] == CDISABLE)
    s.main.c_cc[VINTR] = 'C'&037;       /* Control-C */
#endif /* not SIGNALS_VIA_CHARACTERS */

#ifdef AIX
/* AIX enhanced edit loses NULs, so disable it */
#ifndef IBMR2AIX
  s.main.c_line = 0;
  s.main.c_iflag &= ~ASCEDIT;
#endif
  /* Also, PTY overloads NUL and BREAK.
     don't ignore break, but don't signal either, so it looks like NUL.  */
  s.main.c_iflag &= ~IGNBRK;
  s.main.c_iflag &= ~BRKINT;
  /* rms: Formerly it set s.main.c_cc[VINTR] to 0377 here
     unconditionally.  Then a SIGNALS_VIA_CHARACTERS conditional
     would force it to 0377.  That looks like duplicated code.  */
  s.main.c_cc[VEOL] = CDISABLE;
  s.main.c_cflag = (s.main.c_cflag & ~CBAUD) | B9600; /* baud rate sanity */
#endif /* AIX */

#else /* not HAVE_TERMIO */

  s.main.sg_flags &= ~(ECHO | CRMOD | ANYP | ALLDELAY | RAW | LCASE
                       | CBREAK | TANDEM);
  s.main.sg_flags |= LPASS8;
  s.main.sg_erase = 0377;
  s.main.sg_kill = 0377;
  s.lmode = LLITOUT | s.lmode;        /* Don't strip 8th bit */

#endif /* not HAVE_TERMIO */

  EMACS_SET_TTY (out, &s, 0);

#endif /* not DOS_NT */
}

#endif /* subprocesses */
\f
/* Record a signal code and the handler for it.  */
struct save_signal
{
  int code;
  SIGTYPE (*handler) P_ ((int));
};

static void save_signal_handlers P_ ((struct save_signal *));
static void restore_signal_handlers P_ ((struct save_signal *));

/* Suspend the Emacs process; give terminal to its superior.  */

void
sys_suspend ()
{
#if defined (SIGTSTP) && !defined (MSDOS)

  {
    int pgrp = EMACS_GETPGRP (0);
    EMACS_KILLPG (pgrp, SIGTSTP);
  }

#else /* No SIGTSTP */
/* On a system where suspending is not implemented,
   instead fork a subshell and let it talk directly to the terminal
   while we wait.  */
  sys_subshell ();

#endif /* no SIGTSTP */
}

/* Fork a subshell.  */

void
sys_subshell ()
{
#ifdef DOS_NT   /* Demacs 1.1.2 91/10/20 Manabu Higashida */
  int st;
  char oldwd[MAXPATHLEN+1]; /* Fixed length is safe on MSDOS.  */
#endif
  int pid;
  struct save_signal saved_handlers[5];
  Lisp_Object dir;
  unsigned char *str = 0;
  int len;

  saved_handlers[0].code = SIGINT;
  saved_handlers[1].code = SIGQUIT;
  saved_handlers[2].code = SIGTERM;
#ifdef SIGIO
  saved_handlers[3].code = SIGIO;
  saved_handlers[4].code = 0;
#else
  saved_handlers[3].code = 0;
#endif

  /* Mentioning current_buffer->buffer would mean including buffer.h,
     which somehow wedges the hp compiler.  So instead...  */

  dir = intern ("default-directory");
  if (NILP (Fboundp (dir)))
    goto xyzzy;
  dir = Fsymbol_value (dir);
  if (!STRINGP (dir))
    goto xyzzy;

  dir = expand_and_dir_to_file (Funhandled_file_name_directory (dir), Qnil);
  str = (unsigned char *) alloca (SCHARS (dir) + 2);
  len = SCHARS (dir);
  bcopy (SDATA (dir), str, len);
  if (str[len - 1] != '/') str[len++] = '/';
  str[len] = 0;
 xyzzy:

#ifdef DOS_NT
  pid = 0;
#if __DJGPP__ > 1
  save_signal_handlers (saved_handlers);
  synch_process_alive = 1;
#endif /* __DJGPP__ > 1 */
#else
  pid = vfork ();
  if (pid == -1)
    error ("Can't spawn subshell");
#endif

  if (pid == 0)
    {
      char *sh = 0;

#ifdef DOS_NT    /* MW, Aug 1993 */
      getwd (oldwd);
      if (sh == 0)
        sh = (char *) egetenv ("SUSPEND");      /* KFS, 1994-12-14 */
#endif
      if (sh == 0)
        sh = (char *) egetenv ("SHELL");
      if (sh == 0)
        sh = "sh";

      /* Use our buffer's default directory for the subshell.  */
      if (str)
        chdir ((char *) str);

#ifdef subprocesses
      close_process_descs ();   /* Close Emacs's pipes/ptys */
#endif

#ifdef SET_EMACS_PRIORITY
      {
        extern EMACS_INT emacs_priority;

        if (emacs_priority < 0)
          nice (-emacs_priority);
      }
#endif

#ifdef MSDOS    /* Demacs 1.1.2 91/10/20 Manabu Higashida */
      {
        char *epwd = getenv ("PWD");
        char old_pwd[MAXPATHLEN+1+4];

        /* If PWD is set, pass it with corrected value.  */
        if (epwd)
          {
            strcpy (old_pwd, epwd);
            if (str[len - 1] == '/')
              str[len - 1] = '\0';
            setenv ("PWD", str, 1);
          }
        st = system (sh);
        chdir (oldwd);
        if (epwd)
          putenv (old_pwd);     /* restore previous value */
      }
#else /* not MSDOS */
#ifdef  WINDOWSNT
      /* Waits for process completion */
      pid = _spawnlp (_P_WAIT, sh, sh, NULL);
      chdir (oldwd);
      if (pid == -1)
        write (1, "Can't execute subshell", 22);
#else   /* not WINDOWSNT */
      execlp (sh, sh, (char *) 0);
      write (1, "Can't execute subshell", 22);
      _exit (1);
#endif  /* not WINDOWSNT */
#endif /* not MSDOS */
    }

  /* Do this now if we did not do it before.  */
#if !defined (MSDOS) || __DJGPP__ == 1
  save_signal_handlers (saved_handlers);
  synch_process_alive = 1;
#endif

#ifndef DOS_NT
  wait_for_termination (pid);
#endif
  restore_signal_handlers (saved_handlers);
  synch_process_alive = 0;
}

static void
save_signal_handlers (saved_handlers)
     struct save_signal *saved_handlers;
{
  while (saved_handlers->code)
    {
      saved_handlers->handler
        = (SIGTYPE (*) P_ ((int))) signal (saved_handlers->code, SIG_IGN);
      saved_handlers++;
    }
}

static void
restore_signal_handlers (saved_handlers)
     struct save_signal *saved_handlers;
{
  while (saved_handlers->code)
    {
      signal (saved_handlers->code, saved_handlers->handler);
      saved_handlers++;
    }
}
\f
#ifndef SIGIO
/* If SIGIO is broken, don't do anything. */
void
init_sigio (int fd)
{
}

void
reset_sigio (int fd)
{
}

void
request_sigio (void)
{
}

void
unrequest_sigio (void)
{
}

#else
#ifdef F_SETFL

int old_fcntl_flags[MAXDESC];

void
init_sigio (fd)
     int fd;
{
#ifdef FASYNC
  old_fcntl_flags[fd] = fcntl (fd, F_GETFL, 0) & ~FASYNC;
  fcntl (fd, F_SETFL, old_fcntl_flags[fd] | FASYNC);
#endif
  interrupts_deferred = 0;
}

void
reset_sigio (fd)
     int fd;
{
#ifdef FASYNC
  fcntl (fd, F_SETFL, old_fcntl_flags[fd]);
#endif
}

#ifdef FASYNC           /* F_SETFL does not imply existence of FASYNC */
/* XXX Uhm, FASYNC is not used anymore here. */
/* XXX Yeah, but you need it for SIGIO, don't you? */

void
request_sigio ()
{
  if (noninteractive)
    return;

#ifdef SIGWINCH
  sigunblock (sigmask (SIGWINCH));
#endif
  sigunblock (sigmask (SIGIO));

  interrupts_deferred = 0;
}

void
unrequest_sigio (void)
{ 
  if (noninteractive)
    return;

#if 0 /* XXX What's wrong with blocking SIGIO under X?  */
  if (x_display_list)
    return;
#endif

#ifdef SIGWINCH
  sigblock (sigmask (SIGWINCH));
#endif
  sigblock (sigmask (SIGIO));
  interrupts_deferred = 1;
}

#else /* no FASYNC */
#ifndef MSDOS

void
request_sigio ()
{
  if (noninteractive || read_socket_hook)
    return;

  croak ("request_sigio");
}

void
unrequest_sigio ()
{
  if (noninteractive || read_socket_hook)
    return;

  croak ("unrequest_sigio");
}

#endif /* MSDOS */
#endif /* FASYNC */
#endif /* F_SETFL */
#endif /* SIGIO */
\f
/* Saving and restoring the process group of Emacs's terminal.  */

#ifdef BSD_PGRPS

/* The process group of which Emacs was a member when it initially
   started.

   If Emacs was in its own process group (i.e. inherited_pgroup ==
   getpid ()), then we know we're running under a shell with job
   control (Emacs would never be run as part of a pipeline).
   Everything is fine.

   If Emacs was not in its own process group, then we know we're
   running under a shell (or a caller) that doesn't know how to
   separate itself from Emacs (like sh).  Emacs must be in its own
   process group in order to receive SIGIO correctly.  In this
   situation, we put ourselves in our own pgroup, forcibly set the
   tty's pgroup to our pgroup, and make sure to restore and reinstate
   the tty's pgroup just like any other terminal setting.  If
   inherited_group was not the tty's pgroup, then we'll get a
   SIGTTmumble when we try to change the tty's pgroup, and a CONT if
   it goes foreground in the future, which is what should happen.

   This variable is initialized in emacs.c.  */
int inherited_pgroup;

/* Split off the foreground process group to Emacs alone.  When we are
   in the foreground, but not started in our own process group,
   redirect the tty device handle FD to point to our own process
   group.  We need to be in our own process group to receive SIGIO
   properly.  */
static void
narrow_foreground_group (int fd)
{
  int me = getpid ();

  setpgrp (0, inherited_pgroup);
#if 0
  /* XXX inherited_pgroup should not be zero here, but GTK seems to
     mess this up. */
  if (! inherited_pgroup)
    abort ();                   /* Should not happen. */
#endif
  if (inherited_pgroup != me)
      EMACS_SET_TTY_PGRP (fd, &me); /* XXX This only works on the controlling tty. */
  setpgrp (0, me);
}

/* Set the tty to our original foreground group.  */
static void
widen_foreground_group (int fd)
{
  if (inherited_pgroup != getpid ())
    EMACS_SET_TTY_PGRP (fd, &inherited_pgroup);
  setpgrp (0, inherited_pgroup);
}

#endif /* BSD_PGRPS */
\f
/* Getting and setting emacs_tty structures.  */

/* Set *TC to the parameters associated with the terminal FD.
   Return zero if all's well, or -1 if we ran into an error we
   couldn't deal with.  */
int
emacs_get_tty (fd, settings)
     int fd;
     struct emacs_tty *settings;
{
  /* Retrieve the primary parameters - baud rate, character size, etcetera.  */
#ifdef HAVE_TCATTR
  /* We have those nifty POSIX tcmumbleattr functions.  */
  bzero (&settings->main, sizeof (settings->main));
  if (tcgetattr (fd, &settings->main) < 0)
    return -1;

#else
#ifdef HAVE_TERMIO
  /* The SYSV-style interface?  */
  if (ioctl (fd, TCGETA, &settings->main) < 0)
    return -1;

#else
#ifndef DOS_NT
  /* I give up - I hope you have the BSD ioctls.  */
  if (ioctl (fd, TIOCGETP, &settings->main) < 0)
    return -1;
#endif /* not DOS_NT */
#endif
#endif

  /* Suivant - Do we have to get struct ltchars data?  */
#ifdef HAVE_LTCHARS
  if (ioctl (fd, TIOCGLTC, &settings->ltchars) < 0)
    return -1;
#endif

  /* How about a struct tchars and a wordful of lmode bits?  */
#ifdef HAVE_TCHARS
  if (ioctl (fd, TIOCGETC, &settings->tchars) < 0
      || ioctl (fd, TIOCLGET, &settings->lmode) < 0)
    return -1;
#endif

  /* We have survived the tempest.  */
  return 0;
}


/* Set the parameters of the tty on FD according to the contents of
   *SETTINGS.  If FLUSHP is non-zero, we discard input.
   Return 0 if all went well, and -1 if anything failed.  */

int
emacs_set_tty (fd, settings, flushp)
     int fd;
     struct emacs_tty *settings;
     int flushp;
{
  /* Set the primary parameters - baud rate, character size, etcetera.  */
#ifdef HAVE_TCATTR
  int i;
  /* We have those nifty POSIX tcmumbleattr functions.
     William J. Smith <wjs@wiis.wang.com> writes:
     "POSIX 1003.1 defines tcsetattr to return success if it was
     able to perform any of the requested actions, even if some
     of the requested actions could not be performed.
     We must read settings back to ensure tty setup properly.
     AIX requires this to keep tty from hanging occasionally."  */
  /* This make sure that we don't loop indefinitely in here.  */
  for (i = 0 ; i < 10 ; i++)
    if (tcsetattr (fd, flushp ? TCSAFLUSH : TCSADRAIN, &settings->main) < 0)
      {
        if (errno == EINTR)
          continue;
        else
          return -1;
      }
    else
      {
        struct termios new;

        bzero (&new, sizeof (new));
        /* Get the current settings, and see if they're what we asked for.  */
        tcgetattr (fd, &new);
        /* We cannot use memcmp on the whole structure here because under
         * aix386 the termios structure has some reserved field that may
         * not be filled in.
         */
        if (   new.c_iflag == settings->main.c_iflag
            && new.c_oflag == settings->main.c_oflag
            && new.c_cflag == settings->main.c_cflag
            && new.c_lflag == settings->main.c_lflag
            && memcmp (new.c_cc, settings->main.c_cc, NCCS) == 0)
          break;
        else
          continue;
      }

#else
#ifdef HAVE_TERMIO
  /* The SYSV-style interface?  */
  if (ioctl (fd, flushp ? TCSETAF : TCSETAW, &settings->main) < 0)
    return -1;

#else
#ifndef DOS_NT
  /* I give up - I hope you have the BSD ioctls.  */
  if (ioctl (fd, (flushp) ? TIOCSETP : TIOCSETN, &settings->main) < 0)
    return -1;
#endif /* not DOS_NT */

#endif
#endif

  /* Suivant - Do we have to get struct ltchars data?  */
#ifdef HAVE_LTCHARS
  if (ioctl (fd, TIOCSLTC, &settings->ltchars) < 0)
    return -1;
#endif

  /* How about a struct tchars and a wordful of lmode bits?  */
#ifdef HAVE_TCHARS
  if (ioctl (fd, TIOCSETC, &settings->tchars) < 0
      || ioctl (fd, TIOCLSET, &settings->lmode) < 0)
    return -1;
#endif

  /* We have survived the tempest.  */
  return 0;
}

\f

#ifdef F_SETOWN
int old_fcntl_owner[MAXDESC];
#endif /* F_SETOWN */

/* This may also be defined in stdio,
   but if so, this does no harm,
   and using the same name avoids wasting the other one's space.  */

#if defined (USG)
unsigned char _sobuf[BUFSIZ+8];
#else
char _sobuf[BUFSIZ];
#endif

#ifdef HAVE_LTCHARS
static struct ltchars new_ltchars = {-1,-1,-1,-1,-1,-1};
#endif
#ifdef HAVE_TCHARS
static struct tchars new_tchars = {-1,-1,-1,-1,-1,-1};
#endif

/* Initialize the terminal mode on all tty devices that are currently
   open. */

void
init_all_sys_modes (void)
{
  struct tty_display_info *tty;
  for (tty = tty_list; tty; tty = tty->next)
    init_sys_modes (tty);
}

/* Initialize the terminal mode on the given tty device. */

void
init_sys_modes (tty_out)
     struct tty_display_info *tty_out;
{
  struct emacs_tty tty;

  Vtty_erase_char = Qnil;

  if (noninteractive)
    return;

  if (!tty_out->output)
    return;                     /* The tty is suspended. */
  
#ifdef BSD_PGRPS
#if 0
  /* read_socket_hook is not global anymore.  I think doing this
     unconditionally will not cause any problems. */
  if (! read_socket_hook && EQ (Vinitial_window_system, Qnil))
#endif
    narrow_foreground_group (fileno (tty_out->input));
#endif

  if (! tty_out->old_tty)
    tty_out->old_tty = (struct emacs_tty *) xmalloc (sizeof (struct emacs_tty));
      
  EMACS_GET_TTY (fileno (tty_out->input), tty_out->old_tty);

  tty = *tty_out->old_tty;

#if defined (HAVE_TERMIO) || defined (HAVE_TERMIOS)
  XSETINT (Vtty_erase_char, tty.main.c_cc[VERASE]);

  tty.main.c_iflag |= (IGNBRK); /* Ignore break condition */
  tty.main.c_iflag &= ~ICRNL;   /* Disable map of CR to NL on input */
#ifdef INLCR  /* I'm just being cautious,
                 since I can't check how widespread INLCR is--rms.  */
  tty.main.c_iflag &= ~INLCR;   /* Disable map of NL to CR on input */
#endif
#ifdef ISTRIP
  tty.main.c_iflag &= ~ISTRIP;  /* don't strip 8th bit on input */
#endif
  tty.main.c_lflag &= ~ECHO;    /* Disable echo */
  tty.main.c_lflag &= ~ICANON;  /* Disable erase/kill processing */
#ifdef IEXTEN
  tty.main.c_lflag &= ~IEXTEN;  /* Disable other editing characters.  */
#endif
  tty.main.c_lflag |= ISIG;     /* Enable signals */
  if (tty_out->flow_control)
    {
      tty.main.c_iflag |= IXON; /* Enable start/stop output control */
#ifdef IXANY
      tty.main.c_iflag &= ~IXANY;
#endif /* IXANY */
    }
  else
    tty.main.c_iflag &= ~IXON;  /* Disable start/stop output control */
  tty.main.c_oflag &= ~ONLCR;   /* Disable map of NL to CR-NL
                                   on output */
  tty.main.c_oflag &= ~TAB3;    /* Disable tab expansion */
#ifdef CS8
  if (tty_out->meta_key)
    {
      tty.main.c_cflag |= CS8;  /* allow 8th bit on input */
      tty.main.c_cflag &= ~PARENB;/* Don't check parity */
    }
#endif
  if (tty_out->input == stdin)
    {
      tty.main.c_cc[VINTR] = quit_char; /* C-g (usually) gives SIGINT */
      /* Set up C-g for both SIGQUIT and SIGINT.
         We don't know which we will get, but we handle both alike
         so which one it really gives us does not matter.  */
      tty.main.c_cc[VQUIT] = quit_char;
    }
  else
    {
      /* We normally don't get interrupt or quit signals from tty
         devices other than our controlling terminal; therefore,
         we must handle C-g as normal input.  Unfortunately, this
         means that the interrupt and quit feature must be
         disabled on secondary ttys, or we would not even see the
         keypress.
         
         Note that even though emacsclient could have special code
         to pass SIGINT to Emacs, we should _not_ enable
         interrupt/quit keys for emacsclient frames.  This means
         that we can't break out of loops in C code from a
         secondary tty frame, but we can always decide what
         display the C-g came from, which is more important from a
         usability point of view.  (Consider the case when two
         people work together using the same Emacs instance.)  */
      tty.main.c_cc[VINTR] = CDISABLE;
      tty.main.c_cc[VQUIT] = CDISABLE;
    }
  tty.main.c_cc[VMIN] = 1;      /* Input should wait for at least 1 char */
  tty.main.c_cc[VTIME] = 0;     /* no matter how long that takes.  */
#ifdef VSWTCH
  tty.main.c_cc[VSWTCH] = CDISABLE;     /* Turn off shell layering use
                                           of C-z */
#endif /* VSWTCH */
  
#if defined (__mips__) || defined (HAVE_TCATTR)
#ifdef VSUSP
  tty.main.c_cc[VSUSP] = CDISABLE;      /* Turn off mips handling of C-z.  */
#endif /* VSUSP */
#ifdef V_DSUSP
  tty.main.c_cc[V_DSUSP] = CDISABLE; /* Turn off mips handling of C-y.  */
#endif /* V_DSUSP */
#ifdef VDSUSP /* Some systems have VDSUSP, some have V_DSUSP.  */
  tty.main.c_cc[VDSUSP] = CDISABLE;
#endif /* VDSUSP */
#ifdef VLNEXT
  tty.main.c_cc[VLNEXT] = CDISABLE;
#endif /* VLNEXT */
#ifdef VREPRINT
  tty.main.c_cc[VREPRINT] = CDISABLE;
#endif /* VREPRINT */
#ifdef VWERASE
  tty.main.c_cc[VWERASE] = CDISABLE;
#endif /* VWERASE */
#ifdef VDISCARD
  tty.main.c_cc[VDISCARD] = CDISABLE;
#endif /* VDISCARD */

  if (tty_out->flow_control)
    {
#ifdef VSTART
      tty.main.c_cc[VSTART] = '\021';
#endif /* VSTART */
#ifdef VSTOP
      tty.main.c_cc[VSTOP] = '\023';
#endif /* VSTOP */
    }
  else
    {
#ifdef VSTART
      tty.main.c_cc[VSTART] = CDISABLE;
#endif /* VSTART */
#ifdef VSTOP
      tty.main.c_cc[VSTOP] = CDISABLE;
#endif /* VSTOP */
    }
#endif /* mips or HAVE_TCATTR */

#ifdef AIX
#ifndef IBMR2AIX
  /* AIX enhanced edit loses NULs, so disable it.  */
  tty.main.c_line = 0;
  tty.main.c_iflag &= ~ASCEDIT;
#else
  tty.main.c_cc[VSTRT] = CDISABLE;
  tty.main.c_cc[VSTOP] = CDISABLE;
  tty.main.c_cc[VSUSP] = CDISABLE;
  tty.main.c_cc[VDSUSP] = CDISABLE;
#endif /* IBMR2AIX */
  if (tty_out->flow_control)
    {
#ifdef VSTART
      tty.main.c_cc[VSTART] = '\021';
#endif /* VSTART */
#ifdef VSTOP
      tty.main.c_cc[VSTOP] = '\023';
#endif /* VSTOP */
    }
  /* Also, PTY overloads NUL and BREAK.
     don't ignore break, but don't signal either, so it looks like NUL.
     This really serves a purpose only if running in an XTERM window
     or via TELNET or the like, but does no harm elsewhere.  */
  tty.main.c_iflag &= ~IGNBRK;
  tty.main.c_iflag &= ~BRKINT;
#endif
#else /* if not HAVE_TERMIO */
#ifndef DOS_NT
  XSETINT (Vtty_erase_char, tty.main.sg_erase);
  tty.main.sg_flags &= ~(ECHO | CRMOD | XTABS);
  if (meta_key)
    tty.main.sg_flags |= ANYP;
  tty.main.sg_flags |= interrupt_input ? RAW : CBREAK;
#endif /* not DOS_NT */
#endif /* not HAVE_TERMIO */

  /* If going to use CBREAK mode, we must request C-g to interrupt
     and turn off start and stop chars, etc.  If not going to use
     CBREAK mode, do this anyway so as to turn off local flow
     control for user coming over network on 4.2; in this case,
     only t_stopc and t_startc really matter.  */
#ifndef HAVE_TERMIO
#ifdef HAVE_TCHARS
  /* Note: if not using CBREAK mode, it makes no difference how we
     set this */
  tty.tchars = new_tchars;
  tty.tchars.t_intrc = quit_char;
  if (tty_out->flow_control)
    {
      tty.tchars.t_startc = '\021';
      tty.tchars.t_stopc = '\023';
    }
  
  tty.lmode = LDECCTQ | LLITOUT | LPASS8 | LNOFLSH | tty_out->old_tty.lmode;
  
#endif /* HAVE_TCHARS */
#endif /* not HAVE_TERMIO */

#ifdef HAVE_LTCHARS
  tty.ltchars = new_ltchars;
#endif /* HAVE_LTCHARS */
#ifdef MSDOS    /* Demacs 1.1.2 91/10/20 Manabu Higashida, MW Aug 1993 */
  if (!tty_out->term_initted)
    internal_terminal_init ();
  dos_ttraw (tty_out);
#endif

  EMACS_SET_TTY (fileno (tty_out->input), &tty, 0);

  /* This code added to insure that, if flow-control is not to be used,
     we have an unlocked terminal at the start. */

#ifdef TCXONC
  if (!tty_out->flow_control) ioctl (fileno (tty_out->input), TCXONC, 1);
#endif
#ifdef TIOCSTART
  if (!tty_out->flow_control) ioctl (fileno (tty_out->input), TIOCSTART, 0);
#endif

#if defined (HAVE_TERMIOS) || defined (HPUX)
#ifdef TCOON
  if (!tty_out->flow_control) tcflow (fileno (tty_out->input), TCOON);
#endif
#endif

#ifdef F_SETFL
#ifdef F_GETOWN         /* F_SETFL does not imply existence of F_GETOWN */
  if (interrupt_input)
    {
      old_fcntl_owner[fileno (tty_out->input)] =
        fcntl (fileno (tty_out->input), F_GETOWN, 0);
      fcntl (fileno (tty_out->input), F_SETOWN, getpid ());
      init_sigio (fileno (tty_out->input));
#ifdef HAVE_GPM
      if (gpm_tty == tty_out)
        {
          /* Arrange for mouse events to give us SIGIO signals.  */
          fcntl (gpm_fd, F_SETOWN, getpid ());
          fcntl (gpm_fd, F_SETFL, fcntl (gpm_fd, F_GETFL, 0) | O_NONBLOCK);
          init_sigio (gpm_fd);
        }
#endif /* HAVE_GPM */
    }
#endif /* F_GETOWN */
#endif /* F_SETFL */

#ifdef _IOFBF
  /* This symbol is defined on recent USG systems.
     Someone says without this call USG won't really buffer the file
     even with a call to setbuf. */
  setvbuf (tty_out->output, (char *) _sobuf, _IOFBF, sizeof _sobuf);
#else
  setbuf (tty_out->output, (char *) _sobuf);
#endif

  if (tty_out->terminal->set_terminal_modes_hook)
    tty_out->terminal->set_terminal_modes_hook (tty_out->terminal);

  if (!tty_out->term_initted)
    {
      Lisp_Object tail, frame;
      FOR_EACH_FRAME (tail, frame)
        {
          /* XXX This needs to be revised. */
          if (FRAME_TERMCAP_P (XFRAME (frame))
              && FRAME_TTY (XFRAME (frame)) == tty_out)
            init_frame_faces (XFRAME (frame));
        }
    }

  if (tty_out->term_initted && no_redraw_on_reenter)
    {
      /* XXX This seems wrong on multi-tty. */
      if (display_completed)
        direct_output_forward_char (0);
    }
  else
    {
      Lisp_Object tail, frame;
      frame_garbaged = 1;
      FOR_EACH_FRAME (tail, frame)
        {
          if ((FRAME_TERMCAP_P (XFRAME (frame))
               || FRAME_MSDOS_P (XFRAME (frame)))
              && FRAME_TTY (XFRAME (frame)) == tty_out)
            FRAME_GARBAGED_P (XFRAME (frame)) = 1;
        }
    }

  tty_out->term_initted = 1;
}

/* Return nonzero if safe to use tabs in output.
   At the time this is called, init_sys_modes has not been done yet.  */

int
tabs_safe_p (int fd)
{
  struct emacs_tty etty;

  EMACS_GET_TTY (fd, &etty);
  return EMACS_TTY_TABS_OK (&etty);
}
\f
/* Get terminal size from system.
   Store number of lines into *HEIGHTP and width into *WIDTHP.
   We store 0 if there's no valid information.  */

void
get_tty_size (int fd, int *widthp, int *heightp)
{

#ifdef TIOCGWINSZ

  /* BSD-style.  */
  struct winsize size;

  if (ioctl (fd, TIOCGWINSZ, &size) == -1)
    *widthp = *heightp = 0;
  else
    {
      *widthp = size.ws_col;
      *heightp = size.ws_row;
    }

#else
#ifdef TIOCGSIZE

  /* SunOS - style.  */
  struct ttysize size;

  if (ioctl (fd, TIOCGSIZE, &size) == -1)
    *widthp = *heightp = 0;
  else
    {
      *widthp = size.ts_cols;
      *heightp = size.ts_lines;
    }

#else
#ifdef MSDOS
  *widthp = ScreenCols ();
  *heightp = ScreenRows ();
#else /* system doesn't know size */
  *widthp = 0;
  *heightp = 0;
#endif
#endif /* not SunOS-style */
#endif /* not BSD-style */
}

/* Set the logical window size associated with descriptor FD
   to HEIGHT and WIDTH.  This is used mainly with ptys.  */

int
set_window_size (fd, height, width)
     int fd, height, width;
{
#ifdef TIOCSWINSZ

  /* BSD-style.  */
  struct winsize size;
  size.ws_row = height;
  size.ws_col = width;

  if (ioctl (fd, TIOCSWINSZ, &size) == -1)
    return 0; /* error */
  else
    return 1;

#else
#ifdef TIOCSSIZE

  /* SunOS - style.  */
  struct ttysize size;
  size.ts_lines = height;
  size.ts_cols = width;

  if (ioctl (fd, TIOCGSIZE, &size) == -1)
    return 0;
  else
    return 1;
#else
  return -1;
#endif /* not SunOS-style */
#endif /* not BSD-style */
}

\f

/* Prepare all terminal devices for exiting Emacs. */

void
reset_all_sys_modes (void)
{
  struct tty_display_info *tty;
  for (tty = tty_list; tty; tty = tty->next)
    reset_sys_modes (tty);
}

/* Prepare the terminal for closing it; move the cursor to the
   bottom of the frame, turn off interrupt-driven I/O, etc.  */

void
reset_sys_modes (tty_out)
     struct tty_display_info *tty_out;
{
  if (noninteractive)
    {
      fflush (stdout);
      return;
    }
  if (!tty_out->term_initted)
    return;

  if (!tty_out->output)
    return;                     /* The tty is suspended. */
  
  /* Go to and clear the last line of the terminal. */

  cmgoto (tty_out, FrameRows (tty_out) - 1, 0);
  
  /* Code adapted from tty_clear_end_of_line. */
  if (tty_out->TS_clr_line)
    {
      emacs_tputs (tty_out, tty_out->TS_clr_line, 1, cmputc);
    }
  else
    {                   /* have to do it the hard way */
      int i;
      tty_turn_off_insert (tty_out);
      
      for (i = curX (tty_out); i < FrameCols (tty_out) - 1; i++)
        {
          fputc (' ', tty_out->output);
        }
    }
  
  cmgoto (tty_out, FrameRows (tty_out) - 1, 0);
  fflush (tty_out->output);
  
  if (tty_out->terminal->reset_terminal_modes_hook)
    tty_out->terminal->reset_terminal_modes_hook (tty_out->terminal);

#ifdef BSD_SYSTEM
  /* Avoid possible loss of output when changing terminal modes.  */
  fsync (fileno (tty_out->output));
#endif

#ifdef F_SETFL
#ifdef F_SETOWN         /* F_SETFL does not imply existence of F_SETOWN */
  if (interrupt_input)
    {
      reset_sigio (fileno (tty_out->input));
      fcntl (fileno (tty_out->input), F_SETOWN,
             old_fcntl_owner[fileno (tty_out->input)]);
    }
#endif /* F_SETOWN */
#ifdef O_NDELAY
  fcntl (fileno (tty_out->input), F_SETFL,
         fcntl (fileno (tty_out->input), F_GETFL, 0) & ~O_NDELAY);
#endif
#endif /* F_SETFL */

  if (tty_out->old_tty)
    while (EMACS_SET_TTY (fileno (tty_out->input),
                          tty_out->old_tty, 0) < 0 && errno == EINTR)
      ;

#ifdef MSDOS    /* Demacs 1.1.2 91/10/20 Manabu Higashida */
  dos_ttcooked ();
#endif

#ifdef BSD_PGRPS
  widen_foreground_group (fileno (tty_out->input));
#endif
}
\f
#ifdef HAVE_PTYS

/* Set up the proper status flags for use of a pty.  */

void
setup_pty (fd)
     int fd;
{
  /* I'm told that TOICREMOTE does not mean control chars
     "can't be sent" but rather that they don't have
     input-editing or signaling effects.
     That should be good, because we have other ways
     to do those things in Emacs.
     However, telnet mode seems not to work on 4.2.
     So TIOCREMOTE is turned off now. */

  /* Under hp-ux, if TIOCREMOTE is turned on, some calls
     will hang.  In particular, the "timeout" feature (which
     causes a read to return if there is no data available)
     does this.  Also it is known that telnet mode will hang
     in such a way that Emacs must be stopped (perhaps this
     is the same problem).

     If TIOCREMOTE is turned off, then there is a bug in
     hp-ux which sometimes loses data.  Apparently the
     code which blocks the master process when the internal
     buffer fills up does not work.  Other than this,
     though, everything else seems to work fine.

     Since the latter lossage is more benign, we may as well
     lose that way.  -- cph */
#ifdef FIONBIO
#if defined(UNIX98_PTYS)
  {
    int on = 1;
    ioctl (fd, FIONBIO, &on);
  }
#endif
#endif
}
#endif /* HAVE_PTYS */
\f
#if !defined(CANNOT_DUMP) || !defined(SYSTEM_MALLOC)
/* Some systems that cannot dump also cannot implement these.  */

/*
 *      Return the address of the start of the text segment prior to
 *      doing an unexec.  After unexec the return value is undefined.
 *      See crt0.c for further explanation and _start.
 *
 */

#if !(defined (__NetBSD__) && defined (__ELF__))
#ifndef HAVE_TEXT_START
char *
start_of_text ()
{
#ifdef TEXT_START
  return ((char *) TEXT_START);
#else
  extern int _start ();
  return ((char *) _start);
#endif /* TEXT_START */
}
#endif /* not HAVE_TEXT_START */
#endif

/*
 *      Return the address of the start of the data segment prior to
 *      doing an unexec.  After unexec the return value is undefined.
 *      See crt0.c for further information and definition of data_start.
 *
 *      Apparently, on BSD systems this is etext at startup.  On
 *      USG systems (swapping) this is highly mmu dependent and
 *      is also dependent on whether or not the program is running
 *      with shared text.  Generally there is a (possibly large)
 *      gap between end of text and start of data with shared text.
 *
 *      On Uniplus+ systems with shared text, data starts at a
 *      fixed address.  Each port (from a given oem) is generally
 *      different, and the specific value of the start of data can
 *      be obtained via the UniPlus+ specific "uvar" system call,
 *      however the method outlined in crt0.c seems to be more portable.
 *
 *      Probably what will have to happen when a USG unexec is available,
 *      at least on UniPlus, is temacs will have to be made unshared so
 *      that text and data are contiguous.  Then once loadup is complete,
 *      unexec will produce a shared executable where the data can be
 *      at the normal shared text boundary and the startofdata variable
 *      will be patched by unexec to the correct value.
 *
 */

#ifndef start_of_data
char *
start_of_data ()
{
#ifdef DATA_START
  return ((char *) DATA_START);
#else
#ifdef ORDINARY_LINK
  /*
   * This is a hack.  Since we're not linking crt0.c or pre_crt0.c,
   * data_start isn't defined.  We take the address of environ, which
   * is known to live at or near the start of the system crt0.c, and
   * we don't sweat the handful of bytes that might lose.
   */
  extern char **environ;

  return ((char *) &environ);
#else
  extern int data_start;
  return ((char *) &data_start);
#endif /* ORDINARY_LINK */
#endif /* DATA_START */
}
#endif /* start_of_data */
#endif /* NEED_STARTS (not CANNOT_DUMP or not SYSTEM_MALLOC) */
\f
/* init_system_name sets up the string for the Lisp function
   system-name to return. */

extern Lisp_Object Vsystem_name;

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

#ifdef TRY_AGAIN
#ifndef HAVE_H_ERRNO
extern int h_errno;
#endif
#endif /* TRY_AGAIN */

void
init_system_name ()
{
#ifndef HAVE_GETHOSTNAME
  struct utsname uts;
  uname (&uts);
  Vsystem_name = build_string (uts.nodename);
#else /* HAVE_GETHOSTNAME */
  unsigned int hostname_size = 256;
  char *hostname = (char *) alloca (hostname_size);

  /* Try to get the host name; if the buffer is too short, try
     again.  Apparently, the only indication gethostname gives of
     whether the buffer was large enough is the presence or absence
     of a '\0' in the string.  Eech.  */
  for (;;)
    {
      gethostname (hostname, hostname_size - 1);
      hostname[hostname_size - 1] = '\0';

      /* Was the buffer large enough for the '\0'?  */
      if (strlen (hostname) < hostname_size - 1)
        break;

      hostname_size <<= 1;
      hostname = (char *) alloca (hostname_size);
    }
#ifdef HAVE_SOCKETS
  /* Turn the hostname into the official, fully-qualified hostname.
     Don't do this if we're going to dump; this can confuse system
     libraries on some machines and make the dumped emacs core dump. */
#ifndef CANNOT_DUMP
  if (initialized)
#endif /* not CANNOT_DUMP */
    if (! index (hostname, '.'))
      {
        int count;
#ifdef HAVE_GETADDRINFO
        struct addrinfo *res;
        struct addrinfo hints;
        int ret;

        memset (&hints, 0, sizeof(hints));
        hints.ai_socktype = SOCK_STREAM;
        hints.ai_flags = AI_CANONNAME;

        for (count = 0;; count++)
          {
            if ((ret = getaddrinfo (hostname, NULL, &hints, &res)) == 0
                || ret != EAI_AGAIN)
              break;

            if (count >= 5)
              break;
            Fsleep_for (make_number (1), Qnil);
          }

        if (ret == 0)
          {
            struct addrinfo *it = res;
            while (it)
              {
                char *fqdn = it->ai_canonname;
                if (fqdn && index (fqdn, '.')
                    && strcmp (fqdn, "localhost.localdomain") != 0)
                  break;
                it = it->ai_next;
              }
            if (it)
              {
                hostname = alloca (strlen (it->ai_canonname) + 1);
                strcpy (hostname, it->ai_canonname);
              }
            freeaddrinfo (res);
          }
#else /* !HAVE_GETADDRINFO */
        struct hostent *hp;
        for (count = 0;; count++)
          {

#ifdef TRY_AGAIN
            h_errno = 0;
#endif
            hp = gethostbyname (hostname);
#ifdef TRY_AGAIN
            if (! (hp == 0 && h_errno == TRY_AGAIN))
#endif

              break;

            if (count >= 5)
              break;
            Fsleep_for (make_number (1), Qnil);
          }

        if (hp)
          {
            char *fqdn = (char *) hp->h_name;

            if (!index (fqdn, '.'))
              {
                /* We still don't have a fully qualified domain name.
                   Try to find one in the list of alternate names */
                char **alias = hp->h_aliases;
                while (*alias
                       && (!index (*alias, '.')
                           || !strcmp (*alias, "localhost.localdomain")))
                  alias++;
                if (*alias)
                  fqdn = *alias;
              }
            hostname = fqdn;
          }
#endif /* !HAVE_GETADDRINFO */
      }
#endif /* HAVE_SOCKETS */
  Vsystem_name = build_string (hostname);
#endif /* HAVE_GETHOSTNAME */
  {
    unsigned char *p;
    for (p = SDATA (Vsystem_name); *p; p++)
      if (*p == ' ' || *p == '\t')
        *p = '-';
  }
}
\f
#ifndef MSDOS
#if !defined (HAVE_SELECT)

#include "sysselect.h"
#undef select

#if defined (HAVE_X_WINDOWS) && !defined (HAVE_SELECT)
/* Cause explanatory error message at compile time,
   since the select emulation is not good enough for X.  */
int *x = &x_windows_lose_if_no_select_system_call;
#endif

/* Emulate as much as select as is possible under 4.1 and needed by Gnu Emacs
 * Only checks read descriptors.
 */
/* How long to wait between checking fds in select */
#define SELECT_PAUSE 1
int select_alarmed;

/* For longjmp'ing back to read_input_waiting.  */

jmp_buf read_alarm_throw;

/* Nonzero if the alarm signal should throw back to read_input_waiting.
   The read_socket_hook function sets this to 1 while it is waiting.  */

int read_alarm_should_throw;

SIGTYPE
select_alarm ()
{
  select_alarmed = 1;
  signal (SIGALRM, SIG_IGN);
  SIGNAL_THREAD_CHECK (SIGALRM);
  if (read_alarm_should_throw)
    longjmp (read_alarm_throw, 1);
}

#ifndef WINDOWSNT
/* Only rfds are checked.  */
int
sys_select (nfds, rfds, wfds, efds, timeout)
     int nfds;
     SELECT_TYPE *rfds, *wfds, *efds;
     EMACS_TIME *timeout;
{
  /* XXX This needs to be updated for multi-tty support.  Is there
     anybody who needs to emulate select these days?  */ 
 int ravail = 0;
  SELECT_TYPE orfds;
  int timeoutval;
  int *local_timeout;
  extern int proc_buffered_char[];
#ifndef subprocesses
  int process_tick = 0, update_tick = 0;
#else
  extern int process_tick, update_tick;
#endif
  unsigned char buf;

#if defined (HAVE_SELECT) && defined (HAVE_X_WINDOWS)
  /* If we're using X, then the native select will work; we only need the
     emulation for non-X usage.  */
  if (!NILP (Vinitial_window_system))
    return select (nfds, rfds, wfds, efds, timeout);
#endif
  timeoutval = timeout ? EMACS_SECS (*timeout) : 100000;
  local_timeout = &timeoutval;
  FD_ZERO (&orfds);
  if (rfds)
    {
      orfds = *rfds;
      FD_ZERO (rfds);
    }
  if (wfds)
    FD_ZERO (wfds);
  if (efds)
    FD_ZERO (efds);

  /* If we are looking only for the terminal, with no timeout,
     just read it and wait -- that's more efficient.  */
  if (*local_timeout == 100000 && process_tick == update_tick
      && FD_ISSET (0, &orfds))
    {
      int fd;
      for (fd = 1; fd < nfds; ++fd)
        if (FD_ISSET (fd, &orfds))
          goto hardway;
      if (! detect_input_pending ())
        read_input_waiting ();
      FD_SET (0, rfds);
      return 1;
    }

 hardway:
  /* Once a second, till the timer expires, check all the flagged read
   * descriptors to see if any input is available.  If there is some then
   * set the corresponding bit in the return copy of rfds.
   */
  while (1)
    {
      register int to_check, fd;

      if (rfds)
        {
          for (to_check = nfds, fd = 0; --to_check >= 0; fd++)
            {
              if (FD_ISSET (fd, &orfds))
                {
                  int avail = 0, status = 0;

                  if (fd == 0)
                    avail = detect_input_pending (); /* Special keyboard handler */
                  else
                    {
#ifdef FIONREAD
                      status = ioctl (fd, FIONREAD, &avail);
#else /* no FIONREAD */
                      /* Hoping it will return -1 if nothing available
                         or 0 if all 0 chars requested are read.  */
                      if (proc_buffered_char[fd] >= 0)
                        avail = 1;
                      else
                        {
                          avail = read (fd, &buf, 1);
                          if (avail > 0)
                            proc_buffered_char[fd] = buf;
                        }
#endif /* no FIONREAD */
                    }
                  if (status >= 0 && avail > 0)
                    {
                      FD_SET (fd, rfds);
                      ravail++;
                    }
                }
            }
        }
      if (*local_timeout == 0 || ravail != 0 || process_tick != update_tick)
        break;

      turn_on_atimers (0);
      signal (SIGALRM, select_alarm);
      select_alarmed = 0;
      alarm (SELECT_PAUSE);

      /* Wait for a SIGALRM (or maybe a SIGTINT) */
      while (select_alarmed == 0 && *local_timeout != 0
             && process_tick == update_tick)
        {
          /* If we are interested in terminal input,
             wait by reading the terminal.
             That makes instant wakeup for terminal input at least.  */
          if (FD_ISSET (0, &orfds))
            {
              read_input_waiting ();
              if (detect_input_pending ())
                select_alarmed = 1;
            }
          else
            pause ();
        }
      (*local_timeout) -= SELECT_PAUSE;

      /* Reset the old alarm if there was one.  */
      turn_on_atimers (1);

      if (*local_timeout == 0)  /* Stop on timer being cleared */
        break;
    }
  return ravail;
}
#endif /* not WINDOWSNT */

/* Read keyboard input into the standard buffer,
   waiting for at least one character.  */

void
read_input_waiting ()
{
  /* XXX This needs to be updated for multi-tty support.  Is there
     anybody who needs to emulate select these days?  */
  int nread, i;
  extern int quit_char;

  if (read_socket_hook)
    {
      struct input_event hold_quit;

      EVENT_INIT (hold_quit);
      hold_quit.kind = NO_EVENT;

      read_alarm_should_throw = 0;
      if (! setjmp (read_alarm_throw))
        nread = (*read_socket_hook) (0, 1, &hold_quit);
      else
        nread = -1;

      if (hold_quit.kind != NO_EVENT)
        kbd_buffer_store_event (&hold_quit);
    }
  else
    {
      struct input_event e;
      char buf[3];
      nread = read (fileno (stdin), buf, 1);
      EVENT_INIT (e);

      /* Scan the chars for C-g and store them in kbd_buffer.  */
      e.kind = ASCII_KEYSTROKE_EVENT;
      e.frame_or_window = selected_frame;
      e.modifiers = 0;
      for (i = 0; i < nread; i++)
        {
          /* Convert chars > 0177 to meta events if desired.
             We do this under the same conditions that read_avail_input does.  */
          if (read_socket_hook == 0)
            {
              /* If the user says she has a meta key, then believe her. */
              if (meta_key == 1 && (buf[i] & 0x80))
                e.modifiers = meta_modifier;
              if (meta_key != 2)
                buf[i] &= ~0x80;
            }

          XSETINT (e.code, buf[i]);
          kbd_buffer_store_event (&e);
          /* Don't look at input that follows a C-g too closely.
             This reduces lossage due to autorepeat on C-g.  */
          if (buf[i] == quit_char)
            break;
        }
    }
}

#if !defined (HAVE_SELECT)
#define select sys_select
#endif

#endif /* not HAVE_SELECT */
#endif /* not MSDOS */
\f
/* POSIX signals support - DJB */
/* Anyone with POSIX signals should have ANSI C declarations */

#ifdef POSIX_SIGNALS

sigset_t empty_mask, full_mask;

signal_handler_t
sys_signal (int signal_number, signal_handler_t action)
{
  struct sigaction new_action, old_action;
  sigemptyset (&new_action.sa_mask);
  new_action.sa_handler = action;
  new_action.sa_flags = 0;
#if defined (SA_RESTART)
  /* Emacs mostly works better with restartable system services. If this
     flag exists, we probably want to turn it on here.
     However, on some systems this resets the timeout of `select'
     which means that `select' never finishes if it keeps getting signals.
     BROKEN_SA_RESTART is defined on those systems.  */
  /* It's not clear why the comment above says "mostly works better".  --Stef
     When SYNC_INPUT is set, we don't want SA_RESTART because we need to poll
     for pending input so we need long-running syscalls to be interrupted
     after a signal that sets the interrupt_input_pending flag.  */
  /* Non-interactive keyboard input goes through stdio, where we always
     want restartable system calls.  */
# if defined (BROKEN_SA_RESTART) || defined(SYNC_INPUT)
  if (noninteractive)
# endif
    new_action.sa_flags = SA_RESTART;
#endif
  sigaction (signal_number, &new_action, &old_action);
  return (old_action.sa_handler);
}

#ifndef __GNUC__
/* If we're compiling with GCC, we don't need this function, since it
   can be written as a macro.  */
sigset_t
sys_sigmask (int sig)
{
  sigset_t mask;
  sigemptyset (&mask);
  sigaddset (&mask, sig);
  return mask;
}
#endif

/* I'd like to have these guys return pointers to the mask storage in here,
   but there'd be trouble if the code was saving multiple masks.  I'll be
   safe and pass the structure.  It normally won't be more than 2 bytes
   anyhow. - DJB */

sigset_t
sys_sigblock (sigset_t new_mask)
{
  sigset_t old_mask;
  sigprocmask (SIG_BLOCK, &new_mask, &old_mask);
  return (old_mask);
}

sigset_t
sys_sigunblock (sigset_t new_mask)
{
  sigset_t old_mask;
  sigprocmask (SIG_UNBLOCK, &new_mask, &old_mask);
  return (old_mask);
}

sigset_t
sys_sigsetmask (sigset_t new_mask)
{
  sigset_t old_mask;
  sigprocmask (SIG_SETMASK, &new_mask, &old_mask);
  return (old_mask);
}

#endif /* POSIX_SIGNALS */
\f
#if !defined HAVE_STRSIGNAL && !HAVE_DECL_SYS_SIGLIST
static char *my_sys_siglist[NSIG];
# ifdef sys_siglist
#  undef sys_siglist
# endif
# define sys_siglist my_sys_siglist
#endif

void
init_signals ()
{
#ifdef POSIX_SIGNALS
  sigemptyset (&empty_mask);
  sigfillset (&full_mask);
#endif

#if !defined HAVE_STRSIGNAL && !HAVE_DECL_SYS_SIGLIST
  if (! initialized)
    {
# ifdef SIGABRT
      sys_siglist[SIGABRT] = "Aborted";
# endif
# ifdef SIGAIO
      sys_siglist[SIGAIO] = "LAN I/O interrupt";
# endif
# ifdef SIGALRM
      sys_siglist[SIGALRM] = "Alarm clock";
# endif
# ifdef SIGBUS
      sys_siglist[SIGBUS] = "Bus error";
# endif
# ifdef SIGCLD
      sys_siglist[SIGCLD] = "Child status changed";
# endif
# ifdef SIGCHLD
      sys_siglist[SIGCHLD] = "Child status changed";
# endif
# ifdef SIGCONT
      sys_siglist[SIGCONT] = "Continued";
# endif
# ifdef SIGDANGER
      sys_siglist[SIGDANGER] = "Swap space dangerously low";
# endif
# ifdef SIGDGNOTIFY
      sys_siglist[SIGDGNOTIFY] = "Notification message in queue";
# endif
# ifdef SIGEMT
      sys_siglist[SIGEMT] = "Emulation trap";
# endif
# ifdef SIGFPE
      sys_siglist[SIGFPE] = "Arithmetic exception";
# endif
# ifdef SIGFREEZE
      sys_siglist[SIGFREEZE] = "SIGFREEZE";
# endif
# ifdef SIGGRANT
      sys_siglist[SIGGRANT] = "Monitor mode granted";
# endif
# ifdef SIGHUP
      sys_siglist[SIGHUP] = "Hangup";
# endif
# ifdef SIGILL
      sys_siglist[SIGILL] = "Illegal instruction";
# endif
# ifdef SIGINT
      sys_siglist[SIGINT] = "Interrupt";
# endif
# ifdef SIGIO
      sys_siglist[SIGIO] = "I/O possible";
# endif
# ifdef SIGIOINT
      sys_siglist[SIGIOINT] = "I/O intervention required";
# endif
# ifdef SIGIOT
      sys_siglist[SIGIOT] = "IOT trap";
# endif
# ifdef SIGKILL
      sys_siglist[SIGKILL] = "Killed";
# endif
# ifdef SIGLOST
      sys_siglist[SIGLOST] = "Resource lost";
# endif
# ifdef SIGLWP
      sys_siglist[SIGLWP] = "SIGLWP";
# endif
# ifdef SIGMSG
      sys_siglist[SIGMSG] = "Monitor mode data available";
# endif
# ifdef SIGPHONE
      sys_siglist[SIGWIND] = "SIGPHONE";
# endif
# ifdef SIGPIPE
      sys_siglist[SIGPIPE] = "Broken pipe";
# endif
# ifdef SIGPOLL
      sys_siglist[SIGPOLL] = "Pollable event occurred";
# endif
# ifdef SIGPROF
      sys_siglist[SIGPROF] = "Profiling timer expired";
# endif
# ifdef SIGPTY
      sys_siglist[SIGPTY] = "PTY I/O interrupt";
# endif
# ifdef SIGPWR
      sys_siglist[SIGPWR] = "Power-fail restart";
# endif
# ifdef SIGQUIT
      sys_siglist[SIGQUIT] = "Quit";
# endif
# ifdef SIGRETRACT
      sys_siglist[SIGRETRACT] = "Need to relinguish monitor mode";
# endif
# ifdef SIGSAK
      sys_siglist[SIGSAK] = "Secure attention";
# endif
# ifdef SIGSEGV
      sys_siglist[SIGSEGV] = "Segmentation violation";
# endif
# ifdef SIGSOUND
      sys_siglist[SIGSOUND] = "Sound completed";
# endif
# ifdef SIGSTOP
      sys_siglist[SIGSTOP] = "Stopped (signal)";
# endif
# ifdef SIGSTP
      sys_siglist[SIGSTP] = "Stopped (user)";
# endif
# ifdef SIGSYS
      sys_siglist[SIGSYS] = "Bad argument to system call";
# endif
# ifdef SIGTERM
      sys_siglist[SIGTERM] = "Terminated";
# endif
# ifdef SIGTHAW
      sys_siglist[SIGTHAW] = "SIGTHAW";
# endif
# ifdef SIGTRAP
      sys_siglist[SIGTRAP] = "Trace/breakpoint trap";
# endif
# ifdef SIGTSTP
      sys_siglist[SIGTSTP] = "Stopped (user)";
# endif
# ifdef SIGTTIN
      sys_siglist[SIGTTIN] = "Stopped (tty input)";
# endif
# ifdef SIGTTOU
      sys_siglist[SIGTTOU] = "Stopped (tty output)";
# endif
# ifdef SIGURG
      sys_siglist[SIGURG] = "Urgent I/O condition";
# endif
# ifdef SIGUSR1
      sys_siglist[SIGUSR1] = "User defined signal 1";
# endif
# ifdef SIGUSR2
      sys_siglist[SIGUSR2] = "User defined signal 2";
# endif
# ifdef SIGVTALRM
      sys_siglist[SIGVTALRM] = "Virtual timer expired";
# endif
# ifdef SIGWAITING
      sys_siglist[SIGWAITING] = "Process's LWPs are blocked";
# endif
# ifdef SIGWINCH
      sys_siglist[SIGWINCH] = "Window size changed";
# endif
# ifdef SIGWIND
      sys_siglist[SIGWIND] = "SIGWIND";
# endif
# ifdef SIGXCPU
      sys_siglist[SIGXCPU] = "CPU time limit exceeded";
# endif
# ifdef SIGXFSZ
      sys_siglist[SIGXFSZ] = "File size limit exceeded";
# endif
    }
#endif /* !defined HAVE_STRSIGNAL && !defined HAVE_DECL_SYS_SIGLIST */
}
\f
#ifndef HAVE_RANDOM
#ifdef random
#define HAVE_RANDOM
#endif
#endif

/* Figure out how many bits the system's random number generator uses.
   `random' and `lrand48' are assumed to return 31 usable bits.
   BSD `rand' returns a 31 bit value but the low order bits are unusable;
   so we'll shift it and treat it like the 15-bit USG `rand'.  */

#ifndef RAND_BITS
# ifdef HAVE_RANDOM
#  define RAND_BITS 31
# else /* !HAVE_RANDOM */
#  ifdef HAVE_LRAND48
#   define RAND_BITS 31
#   define random lrand48
#  else /* !HAVE_LRAND48 */
#   define RAND_BITS 15
#   if RAND_MAX == 32767
#    define random rand
#   else /* RAND_MAX != 32767 */
#    if RAND_MAX == 2147483647
#     define random() (rand () >> 16)
#    else /* RAND_MAX != 2147483647 */
#     ifdef USG
#      define random rand
#     else
#      define random() (rand () >> 16)
#     endif /* !USG */
#    endif /* RAND_MAX != 2147483647 */
#   endif /* RAND_MAX != 32767 */
#  endif /* !HAVE_LRAND48 */
# endif /* !HAVE_RANDOM */
#endif /* !RAND_BITS */

void
seed_random (arg)
     long arg;
{
#ifdef HAVE_RANDOM
  srandom ((unsigned int)arg);
#else
# ifdef HAVE_LRAND48
  srand48 (arg);
# else
  srand ((unsigned int)arg);
# endif
#endif
}

/*
 * Build a full Emacs-sized word out of whatever we've got.
 * This suffices even for a 64-bit architecture with a 15-bit rand.
 */
long
get_random ()
{
  long val = random ();
#if VALBITS > RAND_BITS
  val = (val << RAND_BITS) ^ random ();
#if VALBITS > 2*RAND_BITS
  val = (val << RAND_BITS) ^ random ();
#if VALBITS > 3*RAND_BITS
  val = (val << RAND_BITS) ^ random ();
#if VALBITS > 4*RAND_BITS
  val = (val << RAND_BITS) ^ random ();
#endif /* need at least 5 */
#endif /* need at least 4 */
#endif /* need at least 3 */
#endif /* need at least 2 */
  return val & ((1L << VALBITS) - 1);
}

#ifndef HAVE_STRERROR
#ifndef WINDOWSNT
char *
strerror (errnum)
     int errnum;
{
  extern char *sys_errlist[];
  extern int sys_nerr;

  if (errnum >= 0 && errnum < sys_nerr)
    return sys_errlist[errnum];
  return (char *) "Unknown error";
}
#endif /* not WINDOWSNT */
#endif /* ! HAVE_STRERROR */
\f
int
emacs_open (path, oflag, mode)
     const char *path;
     int oflag, mode;
{
  register int rtnval;

  while ((rtnval = open (path, oflag, mode)) == -1
         && (errno == EINTR))
    QUIT;
  return (rtnval);
}

int
emacs_close (fd)
     int fd;
{
  int did_retry = 0;
  register int rtnval;

  while ((rtnval = close (fd)) == -1
         && (errno == EINTR))
    did_retry = 1;

  /* If close is interrupted SunOS 4.1 may or may not have closed the
     file descriptor.  If it did the second close will fail with
     errno = EBADF.  That means we have succeeded.  */
  if (rtnval == -1 && did_retry && errno == EBADF)
    return 0;

  return rtnval;
}

int
emacs_read (fildes, buf, nbyte)
     int fildes;
     char *buf;
     unsigned int nbyte;
{
  register int rtnval;

  while ((rtnval = read (fildes, buf, nbyte)) == -1
         && (errno == EINTR))
    QUIT;
  return (rtnval);
}

int
emacs_write (fildes, buf, nbyte)
     int fildes;
     const char *buf;
     unsigned int nbyte;
{
  register int rtnval, bytes_written;

  bytes_written = 0;

  while (nbyte > 0)
    {
      rtnval = write (fildes, buf, nbyte);

      if (rtnval == -1)
        {
          if (errno == EINTR)
            {
#ifdef SYNC_INPUT
              /* I originally used `QUIT' but that might causes files to
                 be truncated if you hit C-g in the middle of it.  --Stef  */
              process_pending_signals ();
#endif
              continue;
            }
          else
            return (bytes_written ? bytes_written : -1);
        }

      buf += rtnval;
      nbyte -= rtnval;
      bytes_written += rtnval;
    }
  return (bytes_written);
}
\f
#ifdef USG
/*
 *      All of the following are for USG.
 *
 *      On USG systems the system calls are INTERRUPTIBLE by signals
 *      that the user program has elected to catch.  Thus the system call
 *      must be retried in these cases.  To handle this without massive
 *      changes in the source code, we remap the standard system call names
 *      to names for our own functions in sysdep.c that do the system call
 *      with retries.  Actually, for portability reasons, it is good
 *      programming practice, as this example shows, to limit all actual
 *      system calls to a single occurrence in the source.  Sure, this
 *      adds an extra level of function call overhead but it is almost
 *      always negligible.   Fred Fish, Unisoft Systems Inc.
 */

/*
 *      Warning, this function may not duplicate 4.2 action properly
 *      under error conditions.
 */

#ifndef MAXPATHLEN
/* In 4.1, param.h fails to define this.  */
#define MAXPATHLEN 1024
#endif

#ifndef HAVE_GETWD

char *
getwd (pathname)
     char *pathname;
{
  char *npath, *spath;
  extern char *getcwd ();

  BLOCK_INPUT;                  /* getcwd uses malloc */
  spath = npath = getcwd ((char *) 0, MAXPATHLEN);
  if (spath == 0)
    {
      UNBLOCK_INPUT;
      return spath;
    }
  /* On Altos 3068, getcwd can return @hostname/dir, so discard
     up to first slash.  Should be harmless on other systems.  */
  while (*npath && *npath != '/')
    npath++;
  strcpy (pathname, npath);
  free (spath);                 /* getcwd uses malloc */
  UNBLOCK_INPUT;
  return pathname;
}

#endif /* HAVE_GETWD */

/*
 *      Emulate rename using unlink/link.  Note that this is
 *      only partially correct.  Also, doesn't enforce restriction
 *      that files be of same type (regular->regular, dir->dir, etc).
 */

#ifndef HAVE_RENAME

rename (from, to)
     const char *from;
     const char *to;
{
  if (access (from, 0) == 0)
    {
      unlink (to);
      if (link (from, to) == 0)
        if (unlink (from) == 0)
          return (0);
    }
  return (-1);
}

#endif


#if defined(HPUX) && !defined(HAVE_PERROR)

/* HPUX curses library references perror, but as far as we know
   it won't be called.  Anyway this definition will do for now.  */

perror ()
{
}
#endif /* HPUX and not HAVE_PERROR */

#ifndef HAVE_DUP2

/*
 *      Emulate BSD dup2.  First close newd if it already exists.
 *      Then, attempt to dup oldd.  If not successful, call dup2 recursively
 *      until we are, then close the unsuccessful ones.
 */

dup2 (oldd, newd)
     int oldd;
     int newd;
{
  register int fd, ret;

  emacs_close (newd);

#ifdef F_DUPFD
  return fcntl (oldd, F_DUPFD, newd);
#else
  fd = dup (old);
  if (fd == -1)
    return -1;
  if (fd == new)
    return new;
  ret = dup2 (old,new);
  emacs_close (fd);
  return ret;
#endif
}

#endif /* not HAVE_DUP2 */

/*
 *      Gettimeofday.  Simulate as much as possible.  Only accurate
 *      to nearest second.  Emacs doesn't use tzp so ignore it for now.
 *      Only needed when subprocesses are defined.
 */

#ifdef subprocesses
#ifndef HAVE_GETTIMEOFDAY
#ifdef HAVE_TIMEVAL

/* ARGSUSED */
int
gettimeofday (tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;
{
  extern long time ();

  tp->tv_sec = time ((long *)0);
  tp->tv_usec = 0;
  if (tzp != 0)
    tzp->tz_minuteswest = -1;
  return 0;
}

#endif
#endif
#endif /* subprocess && !HAVE_GETTIMEOFDAY && HAVE_TIMEVAL */

/*
 *      This function will go away as soon as all the stubs fixed. (fnf)
 */

void
croak (badfunc)
     char *badfunc;
{
  printf ("%s not yet implemented\r\n", badfunc);
  reset_all_sys_modes ();
  exit (1);
}

#endif /* USG */
\f
/* Directory routines for systems that don't have them. */

#ifdef SYSV_SYSTEM_DIR

#include <dirent.h>

#if !defined (HAVE_CLOSEDIR)

int
closedir (DIR *dirp /* stream from opendir */)
{
  int rtnval;

  rtnval = emacs_close (dirp->dd_fd);

  /* Some systems (like Solaris) allocate the buffer and the DIR all
     in one block.  Why in the world are we freeing this ourselves
     anyway?  */
#if ! defined (SOLARIS2)
  xfree ((char *) dirp->dd_buf); /* directory block defined in <dirent.h> */
#endif
  xfree ((char *) dirp);

  return rtnval;
}
#endif /* not HAVE_CLOSEDIR */
#endif /* SYSV_SYSTEM_DIR */

\f
int
set_file_times (filename, atime, mtime)
     const char *filename;
     EMACS_TIME atime, mtime;
{
#ifdef HAVE_UTIMES
  struct timeval tv[2];
  tv[0] = atime;
  tv[1] = mtime;
  return utimes (filename, tv);
#else /* not HAVE_UTIMES */
  struct utimbuf utb;
  utb.actime = EMACS_SECS (atime);
  utb.modtime = EMACS_SECS (mtime);
  return utime (filename, &utb);
#endif /* not HAVE_UTIMES */
}
\f
/* mkdir and rmdir functions, for systems which don't have them.  */

#ifndef HAVE_MKDIR
/*
 * Written by Robert Rother, Mariah Corporation, August 1985.
 *
 * If you want it, it's yours.  All I ask in return is that if you
 * figure out how to do this in a Bourne Shell script you send me
 * a copy.
 *                                      sdcsvax!rmr or rmr@uscd
 *
 * Severely hacked over by John Gilmore to make a 4.2BSD compatible
 * subroutine.  11Mar86; hoptoad!gnu
 *
 * Modified by rmtodd@uokmax 6-28-87 -- when making an already existing dir,
 * subroutine didn't return EEXIST.  It does now.
 */

/*
 * Make a directory.
 */
int
mkdir (dpath, dmode)
     char *dpath;
     int dmode;
{
  int cpid, status, fd;
  struct stat statbuf;

  if (stat (dpath, &statbuf) == 0)
    {
      errno = EEXIST;           /* Stat worked, so it already exists */
      return -1;
    }

  /* If stat fails for a reason other than non-existence, return error */
  if (errno != ENOENT)
    return -1;

  synch_process_alive = 1;
  switch (cpid = fork ())
    {

    case -1:                    /* Error in fork */
      return (-1);              /* Errno is set already */

    case 0:                     /* Child process */
      /*
                 * Cheap hack to set mode of new directory.  Since this
                 * child process is going away anyway, we zap its umask.
                 * FIXME, this won't suffice to set SUID, SGID, etc. on this
                 * directory.  Does anybody care?
                 */
      status = umask (0);       /* Get current umask */
      status = umask (status | (0777 & ~dmode));        /* Set for mkdir */
      fd = emacs_open ("/dev/null", O_RDWR, 0);
      if (fd >= 0)
        {
          dup2 (fd, 0);
          dup2 (fd, 1);
          dup2 (fd, 2);
        }
      execl ("/bin/mkdir", "mkdir", dpath, (char *) 0);
      _exit (-1);               /* Can't exec /bin/mkdir */

    default:                    /* Parent process */
      wait_for_termination (cpid);
    }

  if (synch_process_death != 0 || synch_process_retcode != 0
      || synch_process_termsig != 0)
    {
      errno = EIO;              /* We don't know why, but */
      return -1;                /* /bin/mkdir failed */
    }

  return 0;
}
#endif /* not HAVE_MKDIR */

#ifndef HAVE_RMDIR
int
rmdir (dpath)
     char *dpath;
{
  int cpid, status, fd;
  struct stat statbuf;

  if (stat (dpath, &statbuf) != 0)
    {
      /* Stat just set errno.  We don't have to */
      return -1;
    }

  synch_process_alive = 1;
  switch (cpid = fork ())
    {

    case -1:                    /* Error in fork */
      return (-1);              /* Errno is set already */

    case 0:                     /* Child process */
      fd = emacs_open ("/dev/null", O_RDWR, 0);
      if (fd >= 0)
        {
          dup2 (fd, 0);
          dup2 (fd, 1);
          dup2 (fd, 2);
        }
      execl ("/bin/rmdir", "rmdir", dpath, (char *) 0);
      _exit (-1);               /* Can't exec /bin/rmdir */

    default:                    /* Parent process */
      wait_for_termination (cpid);
    }

  if (synch_process_death != 0 || synch_process_retcode != 0
      || synch_process_termsig != 0)
    {
      errno = EIO;              /* We don't know why, but */
      return -1;                /* /bin/rmdir failed */
    }

  return 0;
}
#endif /* !HAVE_RMDIR */

\f
#ifndef BSTRING

#ifndef bzero

void
bzero (b, length)
     register char *b;
     register int length;
{
  while (length-- > 0)
    *b++ = 0;
}

#endif /* no bzero */
#endif /* BSTRING */

#if (!defined (BSTRING) && !defined (bcopy)) || defined (NEED_BCOPY)
#undef bcopy

/* Saying `void' requires a declaration, above, where bcopy is used
   and that declaration causes pain for systems where bcopy is a macro.  */
bcopy (b1, b2, length)
     register char *b1;
     register char *b2;
     register int length;
{
  while (length-- > 0)
    *b2++ = *b1++;
}
#endif /* (!defined (BSTRING) && !defined (bcopy)) || defined (NEED_BCOPY) */

#ifndef BSTRING
#ifndef bcmp
int
bcmp (b1, b2, length)   /* This could be a macro! */
     register char *b1;
     register char *b2;
     register int length;
{
  while (length-- > 0)
    if (*b1++ != *b2++)
      return 1;

  return 0;
}
#endif /* no bcmp */
#endif /* not BSTRING */
\f
#ifndef HAVE_STRSIGNAL
char *
strsignal (code)
     int code;
{
  char *signame = 0;

  if (0 <= code && code < NSIG)
    {
      /* Cast to suppress warning if the table has const char *.  */
      signame = (char *) sys_siglist[code];
    }

  return signame;
}
#endif /* HAVE_STRSIGNAL */
\f
#ifdef HAVE_TERMIOS
/* For make-serial-process  */
int serial_open (char *port)
{
  int fd = -1;

  fd = emacs_open ((char*) port,
                   O_RDWR
#ifdef O_NONBLOCK
                   | O_NONBLOCK
#else
                   | O_NDELAY
#endif
#ifdef O_NOCTTY
                   | O_NOCTTY
#endif
                   , 0);
  if (fd < 0)
    {
      error ("Could not open %s: %s",
             port, emacs_strerror (errno));
    }
#ifdef TIOCEXCL
  ioctl (fd, TIOCEXCL, (char *) 0);
#endif

  return fd;
}
#endif /* TERMIOS  */

#ifdef HAVE_TERMIOS

#if !defined (HAVE_CFMAKERAW)
/* Workaround for targets which are missing cfmakeraw.  */
/* Pasted from man page.  */
static void cfmakeraw (struct termios *termios_p)
{
    termios_p->c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP|INLCR|IGNCR|ICRNL|IXON);
    termios_p->c_oflag &= ~OPOST;
    termios_p->c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
    termios_p->c_cflag &= ~(CSIZE|PARENB);
    termios_p->c_cflag |= CS8;
}
#endif /* !defined (HAVE_CFMAKERAW */

#if !defined (HAVE_CFSETSPEED)
/* Workaround for targets which are missing cfsetspeed.  */
static int cfsetspeed (struct termios *termios_p, speed_t vitesse)
{
  return (cfsetispeed (termios_p, vitesse)
          + cfsetospeed (termios_p, vitesse));
}
#endif

/* For serial-process-configure  */
void
serial_configure (struct Lisp_Process *p,
                      Lisp_Object contact)
{
  Lisp_Object childp2 = Qnil;
  Lisp_Object tem = Qnil;
  struct termios attr;
  int err = -1;
  char summary[4] = "???"; /* This usually becomes "8N1".  */

  childp2 = Fcopy_sequence (p->childp);

  /* Read port attributes and prepare default configuration.  */
  err = tcgetattr (p->outfd, &attr);
  if (err != 0)
    error ("tcgetattr() failed: %s", emacs_strerror (errno));
  cfmakeraw (&attr);
#if defined (CLOCAL)
  attr.c_cflag |= CLOCAL;
#endif
#if defined (CREAD)
  attr.c_cflag |= CREAD;
#endif

  /* Configure speed.  */
  if (!NILP (Fplist_member (contact, QCspeed)))
    tem = Fplist_get (contact, QCspeed);
  else
    tem = Fplist_get (p->childp, QCspeed);
  CHECK_NUMBER (tem);
  err = cfsetspeed (&attr, XINT (tem));
  if (err != 0)
    error ("cfsetspeed(%d) failed: %s", XINT (tem), emacs_strerror (errno));
  childp2 = Fplist_put (childp2, QCspeed, tem);

  /* Configure bytesize.  */
  if (!NILP (Fplist_member (contact, QCbytesize)))
    tem = Fplist_get (contact, QCbytesize);
  else
    tem = Fplist_get (p->childp, QCbytesize);
  if (NILP (tem))
    tem = make_number (8);
  CHECK_NUMBER (tem);
  if (XINT (tem) != 7 && XINT (tem) != 8)
    error (":bytesize must be nil (8), 7, or 8");
  summary[0] = XINT(tem) + '0';
#if defined (CSIZE) && defined (CS7) && defined (CS8)
  attr.c_cflag &= ~CSIZE;
  attr.c_cflag |= ((XINT (tem) == 7) ? CS7 : CS8);
#else
  /* Don't error on bytesize 8, which should be set by cfmakeraw.  */
  if (XINT (tem) != 8)
    error ("Bytesize cannot be changed");
#endif
  childp2 = Fplist_put (childp2, QCbytesize, tem);

  /* Configure parity.  */
  if (!NILP (Fplist_member (contact, QCparity)))
    tem = Fplist_get (contact, QCparity);
  else
    tem = Fplist_get (p->childp, QCparity);
  if (!NILP (tem) && !EQ (tem, Qeven) && !EQ (tem, Qodd))
    error (":parity must be nil (no parity), `even', or `odd'");
#if defined (PARENB) && defined (PARODD) && defined (IGNPAR) && defined (INPCK)
  attr.c_cflag &= ~(PARENB | PARODD);
  attr.c_iflag &= ~(IGNPAR | INPCK);
  if (NILP (tem))
    {
      summary[1] = 'N';
    }
  else if (EQ (tem, Qeven))
    {
      summary[1] = 'E';
      attr.c_cflag |= PARENB;
      attr.c_iflag |= (IGNPAR | INPCK);
    }
  else if (EQ (tem, Qodd))
    {
      summary[1] = 'O';
      attr.c_cflag |= (PARENB | PARODD);
      attr.c_iflag |= (IGNPAR | INPCK);
    }
#else
  /* Don't error on no parity, which should be set by cfmakeraw.  */
  if (!NILP (tem))
    error ("Parity cannot be configured");
#endif
  childp2 = Fplist_put (childp2, QCparity, tem);

  /* Configure stopbits.  */
  if (!NILP (Fplist_member (contact, QCstopbits)))
    tem = Fplist_get (contact, QCstopbits);
  else
    tem = Fplist_get (p->childp, QCstopbits);
  if (NILP (tem))
    tem = make_number (1);
  CHECK_NUMBER (tem);
  if (XINT (tem) != 1 && XINT (tem) != 2)
    error (":stopbits must be nil (1 stopbit), 1, or 2");
  summary[2] = XINT (tem) + '0';
#if defined (CSTOPB)
  attr.c_cflag &= ~CSTOPB;
  if (XINT (tem) == 2)
    attr.c_cflag |= CSTOPB;
#else
  /* Don't error on 1 stopbit, which should be set by cfmakeraw.  */
  if (XINT (tem) != 1)
    error ("Stopbits cannot be configured");
#endif
  childp2 = Fplist_put (childp2, QCstopbits, tem);

  /* Configure flowcontrol.  */
  if (!NILP (Fplist_member (contact, QCflowcontrol)))
    tem = Fplist_get (contact, QCflowcontrol);
  else
    tem = Fplist_get (p->childp, QCflowcontrol);
  if (!NILP (tem) && !EQ (tem, Qhw) && !EQ (tem, Qsw))
    error (":flowcontrol must be nil (no flowcontrol), `hw', or `sw'");
#if defined (CRTSCTS)
  attr.c_cflag &= ~CRTSCTS;
#endif
#if defined (CNEW_RTSCTS)
  attr.c_cflag &= ~CNEW_RTSCTS;
#endif
#if defined (IXON) && defined (IXOFF)
  attr.c_iflag &= ~(IXON | IXOFF);
#endif
  if (NILP (tem))
    {
      /* Already configured.  */
    }
  else if (EQ (tem, Qhw))
    {
#if defined (CRTSCTS)
      attr.c_cflag |= CRTSCTS;
#elif defined (CNEW_RTSCTS)
      attr.c_cflag |= CNEW_RTSCTS;
#else
      error ("Hardware flowcontrol (RTS/CTS) not supported");
#endif
    }
  else if (EQ (tem, Qsw))
    {
#if defined (IXON) && defined (IXOFF)
      attr.c_iflag |= (IXON | IXOFF);
#else
      error ("Software flowcontrol (XON/XOFF) not supported");
#endif
    }
  childp2 = Fplist_put (childp2, QCflowcontrol, tem);

  /* Activate configuration.  */
  err = tcsetattr (p->outfd, TCSANOW, &attr);
  if (err != 0)
    error ("tcsetattr() failed: %s", emacs_strerror (errno));

  childp2 = Fplist_put (childp2, QCsummary, build_string (summary));
  p->childp = childp2;

}
#endif /* TERMIOS  */
\f
/* System depended enumeration of and access to system processes a-la ps(1).  */

#ifdef HAVE_PROCFS

/* Process enumeration and access via /proc.  */

Lisp_Object
list_system_processes ()
{
  Lisp_Object procdir, match, proclist, next;
  struct gcpro gcpro1, gcpro2;
  register Lisp_Object tail;

  GCPRO2 (procdir, match);
  /* For every process on the system, there's a directory in the
     "/proc" pseudo-directory whose name is the numeric ID of that
     process.  */
  procdir = build_string ("/proc");
  match = build_string ("[0-9]+");
  proclist = directory_files_internal (procdir, Qnil, match, Qt, 0, Qnil);

  /* `proclist' gives process IDs as strings.  Destructively convert
     each string into a number.  */
  for (tail = proclist; CONSP (tail); tail = next)
    {
      next = XCDR (tail);
      XSETCAR (tail, Fstring_to_number (XCAR (tail), Qnil));
    }
  UNGCPRO;

  /* directory_files_internal returns the files in reverse order; undo
     that.  */
  proclist = Fnreverse (proclist);
  return proclist;
}

/* The WINDOWSNT implementation is in w32.c.
   The MSDOS implementation is in dosfns.c.  */
#elif !defined (WINDOWSNT) && !defined (MSDOS)

Lisp_Object
list_system_processes ()
{
  return Qnil;
}

#endif /* !defined (WINDOWSNT) */

#ifdef GNU_LINUX
static void
time_from_jiffies (unsigned long long tval, long hz,
                   time_t *sec, unsigned *usec)
{
  unsigned long long ullsec;

  *sec = tval / hz;
  ullsec = *sec;
  tval -= ullsec * hz;
  /* Careful: if HZ > 1 million, then integer division by it yields zero.  */
  if (hz <= 1000000)
    *usec = tval * 1000000 / hz;
  else
    *usec = tval / (hz / 1000000);
}

static Lisp_Object
ltime_from_jiffies (unsigned long long tval, long hz)
{
  time_t sec;
  unsigned usec;

  time_from_jiffies (tval, hz, &sec, &usec);

  return list3 (make_number ((sec >> 16) & 0xffff),
                make_number (sec & 0xffff),
                make_number (usec));
}

static void
get_up_time (time_t *sec, unsigned *usec)
{
  FILE *fup;

  *sec = *usec = 0;

  BLOCK_INPUT;
  fup = fopen ("/proc/uptime", "r");

  if (fup)
    {
      double uptime, idletime;

      /* The numbers in /proc/uptime use C-locale decimal point, but
         we already set ourselves to the C locale (see `fixup_locale'
         in emacs.c).  */
      if (2 <= fscanf (fup, "%lf %lf", &uptime, &idletime))
        {
          *sec = uptime;
          *usec = (uptime - *sec) * 1000000;
        }
      fclose (fup);
    }
  UNBLOCK_INPUT;
}

#define MAJOR(d) (((unsigned)(d) >> 8) & 0xfff)
#define MINOR(d) (((unsigned)(d) & 0xff) | (((unsigned)(d) & 0xfff00000) >> 12))

static Lisp_Object
procfs_ttyname (int rdev)
{
  FILE *fdev = NULL;
  char name[PATH_MAX];

  BLOCK_INPUT;
  fdev = fopen ("/proc/tty/drivers", "r");

  if (fdev)
    {
      unsigned major;
      unsigned long minor_beg, minor_end;
      char minor[25];   /* 2 32-bit numbers + dash */
      char *endp;

      while (!feof (fdev) && !ferror (fdev))
        {
          if (3 <= fscanf (fdev, "%*s %s %u %s %*s\n", name, &major, minor)
              && major == MAJOR (rdev))
            {
              minor_beg = strtoul (minor, &endp, 0);
              if (*endp == '\0')
                minor_end = minor_beg;
              else if (*endp == '-')
                minor_end = strtoul (endp + 1, &endp, 0);
              else
                continue;

              if (MINOR (rdev) >= minor_beg && MINOR (rdev) <= minor_end)
                {
                  sprintf (name + strlen (name), "%u", MINOR (rdev));
                  break;
                }
            }
        }
      fclose (fdev);
    }
  UNBLOCK_INPUT;
  return build_string (name);
}

static unsigned long
procfs_get_total_memory (void)
{
  FILE *fmem = NULL;
  unsigned long retval = 2 * 1024 * 1024; /* default: 2GB */

  BLOCK_INPUT;
  fmem = fopen ("/proc/meminfo", "r");

  if (fmem)
    {
      unsigned long entry_value;
      char entry_name[20];      /* the longest I saw is 13+1 */

      while (!feof (fmem) && !ferror (fmem))
        {
          if (2 <= fscanf (fmem, "%s %lu kB\n", entry_name, &entry_value)
              && strcmp (entry_name, "MemTotal:") == 0)
            {
              retval = entry_value;
              break;
            }
        }
      fclose (fmem);
    }
  UNBLOCK_INPUT;
  return retval;
}

Lisp_Object
system_process_attributes (Lisp_Object pid)
{
  char procfn[PATH_MAX], fn[PATH_MAX];
  struct stat st;
  struct passwd *pw;
  struct group *gr;
  long clocks_per_sec;
  char *procfn_end;
  char procbuf[1025], *p, *q;
  int fd;
  ssize_t nread;
  const char *cmd = NULL;
  char *cmdline = NULL;
  size_t cmdsize = 0, cmdline_size;
  unsigned char c;
  int proc_id, ppid, uid, gid, pgrp, sess, tty, tpgid, thcount;
  unsigned long long utime, stime, cutime, cstime, start;
  long priority, nice, rss;
  unsigned long minflt, majflt, cminflt, cmajflt, vsize;
  time_t sec;
  unsigned usec;
  EMACS_TIME tnow, tstart, tboot, telapsed,ttotal;
  double pcpu, pmem;
  Lisp_Object attrs = Qnil;
  Lisp_Object cmd_str, decoded_cmd, tem;
  struct gcpro gcpro1, gcpro2;
  EMACS_INT uid_eint, gid_eint;

  CHECK_NUMBER_OR_FLOAT (pid);
  proc_id = FLOATP (pid) ? XFLOAT_DATA (pid) : XINT (pid);
  sprintf (procfn, "/proc/%u", proc_id);
  if (stat (procfn, &st) < 0)
    return attrs;

  GCPRO2 (attrs, decoded_cmd);

  /* euid egid */
  uid = st.st_uid;
  /* Use of EMACS_INT stops GCC whining about limited range of data type.  */
  uid_eint = uid;
  attrs = Fcons (Fcons (Qeuid, make_fixnum_or_float (uid_eint)), attrs);
  BLOCK_INPUT;
  pw = getpwuid (uid);
  UNBLOCK_INPUT;
  if (pw)
    attrs = Fcons (Fcons (Quser, build_string (pw->pw_name)), attrs);

  gid = st.st_gid;
  gid_eint = gid;
  attrs = Fcons (Fcons (Qegid, make_fixnum_or_float (gid_eint)), attrs);
  BLOCK_INPUT;
  gr = getgrgid (gid);
  UNBLOCK_INPUT;
  if (gr)
    attrs = Fcons (Fcons (Qgroup, build_string (gr->gr_name)), attrs);

  strcpy (fn, procfn);
  procfn_end = fn + strlen (fn);
  strcpy (procfn_end, "/stat");
  fd = emacs_open (fn, O_RDONLY, 0);
  if (fd >= 0 && (nread = emacs_read (fd, procbuf, sizeof(procbuf) - 1)) > 0)
    {
      procbuf[nread] = '\0';
      p = procbuf;

      p = strchr (p, '(');
      if (p != NULL)
        {
          q = strrchr (p + 1, ')');
          /* comm */
          if (q != NULL)
            {
              cmd = p + 1;
              cmdsize = q - cmd;
            }
        }
      else
        q = NULL;
      if (cmd == NULL)
        {
          cmd = "???";
          cmdsize = 3;
        }
      /* Command name is encoded in locale-coding-system; decode it.  */
      cmd_str = make_unibyte_string (cmd, cmdsize);
      decoded_cmd = code_convert_string_norecord (cmd_str,
                                                  Vlocale_coding_system, 0);
      attrs = Fcons (Fcons (Qcomm, decoded_cmd), attrs);

      if (q)
        {
          EMACS_INT ppid_eint, pgrp_eint, sess_eint, tpgid_eint, thcount_eint;
          p = q + 2;
          /* state ppid pgrp sess tty tpgid . minflt cminflt majflt cmajflt utime stime cutime cstime priority nice thcount . start vsize rss */
          sscanf (p, "%c %d %d %d %d %d %*u %lu %lu %lu %lu %Lu %Lu %Lu %Lu %ld %ld %d %*d %Lu %lu %ld",
                  &c, &ppid, &pgrp, &sess, &tty, &tpgid,
                  &minflt, &cminflt, &majflt, &cmajflt,
                  &utime, &stime, &cutime, &cstime,
                  &priority, &nice, &thcount, &start, &vsize, &rss);
          {
            char state_str[2];

            state_str[0] = c;
            state_str[1] = '\0';
            tem =  build_string (state_str);
            attrs = Fcons (Fcons (Qstate, tem), attrs);
          }
          /* Stops GCC whining about limited range of data type.  */
          ppid_eint = ppid;
          pgrp_eint = pgrp;
          sess_eint = sess;
          tpgid_eint = tpgid;
          thcount_eint = thcount;
          attrs = Fcons (Fcons (Qppid, make_fixnum_or_float (ppid_eint)), attrs);
          attrs = Fcons (Fcons (Qpgrp, make_fixnum_or_float (pgrp_eint)), attrs);
          attrs = Fcons (Fcons (Qsess, make_fixnum_or_float (sess_eint)), attrs);
          attrs = Fcons (Fcons (Qttname, procfs_ttyname (tty)), attrs);
          attrs = Fcons (Fcons (Qtpgid, make_fixnum_or_float (tpgid_eint)), attrs);
          attrs = Fcons (Fcons (Qminflt, make_fixnum_or_float (minflt)), attrs);
          attrs = Fcons (Fcons (Qmajflt, make_fixnum_or_float (majflt)), attrs);
          attrs = Fcons (Fcons (Qcminflt, make_fixnum_or_float (cminflt)), attrs);
          attrs = Fcons (Fcons (Qcmajflt, make_fixnum_or_float (cmajflt)), attrs);
          clocks_per_sec = sysconf (_SC_CLK_TCK);
          if (clocks_per_sec < 0)
            clocks_per_sec = 100;
          attrs = Fcons (Fcons (Qutime,
                                ltime_from_jiffies (utime, clocks_per_sec)),
                         attrs);
          attrs = Fcons (Fcons (Qstime,
                                ltime_from_jiffies (stime, clocks_per_sec)),
                         attrs);
          attrs = Fcons (Fcons (Qtime,
                                ltime_from_jiffies (stime+utime, clocks_per_sec)),
                         attrs);
          attrs = Fcons (Fcons (Qcutime,
                                ltime_from_jiffies (cutime, clocks_per_sec)),
                         attrs);
          attrs = Fcons (Fcons (Qcstime,
                                ltime_from_jiffies (cstime, clocks_per_sec)),
                         attrs);
          attrs = Fcons (Fcons (Qctime,
                                ltime_from_jiffies (cstime+cutime, clocks_per_sec)),
                         attrs);
          attrs = Fcons (Fcons (Qpri, make_number (priority)), attrs);
          attrs = Fcons (Fcons (Qnice, make_number (nice)), attrs);
          attrs = Fcons (Fcons (Qthcount, make_fixnum_or_float (thcount_eint)), attrs);
          EMACS_GET_TIME (tnow);
          get_up_time (&sec, &usec);
          EMACS_SET_SECS (telapsed, sec);
          EMACS_SET_USECS (telapsed, usec);
          EMACS_SUB_TIME (tboot, tnow, telapsed);
          time_from_jiffies (start, clocks_per_sec, &sec, &usec);
          EMACS_SET_SECS (tstart, sec);
          EMACS_SET_USECS (tstart, usec);
          EMACS_ADD_TIME (tstart, tboot, tstart);
          attrs = Fcons (Fcons (Qstart,
                                list3 (make_number
                                       ((EMACS_SECS (tstart) >> 16) & 0xffff),
                                       make_number
                                       (EMACS_SECS (tstart) & 0xffff),
                                       make_number
                                       (EMACS_USECS (tstart)))),
                         attrs);
          attrs = Fcons (Fcons (Qvsize, make_fixnum_or_float (vsize/1024)), attrs);
          attrs = Fcons (Fcons (Qrss, make_fixnum_or_float (4*rss)), attrs);
          EMACS_SUB_TIME (telapsed, tnow, tstart);
          attrs = Fcons (Fcons (Qetime,
                                list3 (make_number
                                       ((EMACS_SECS (telapsed) >> 16) & 0xffff),
                                       make_number
                                       (EMACS_SECS (telapsed) & 0xffff),
                                       make_number
                                       (EMACS_USECS (telapsed)))),
                         attrs);
          time_from_jiffies (utime + stime, clocks_per_sec, &sec, &usec);
          pcpu = (sec + usec / 1000000.0) / (EMACS_SECS (telapsed) + EMACS_USECS (telapsed) / 1000000.0);
          if (pcpu > 1.0)
            pcpu = 1.0;
          attrs = Fcons (Fcons (Qpcpu, make_float (100 * pcpu)), attrs);
          pmem = 4.0 * 100 * rss / procfs_get_total_memory ();
          if (pmem > 100)
            pmem = 100;
          attrs = Fcons (Fcons (Qpmem, make_float (pmem)), attrs);
        }
    }
  if (fd >= 0)
    emacs_close (fd);

  /* args */
  strcpy (procfn_end, "/cmdline");
  fd = emacs_open (fn, O_RDONLY, 0);
  if (fd >= 0)
    {
      for (cmdline_size = 0; emacs_read (fd, &c, 1) == 1; cmdline_size++)
        {
          if (isspace (c) || c == '\\')
            cmdline_size++;     /* for later quoting, see below */
        }
      if (cmdline_size)
        {
          cmdline = xmalloc (cmdline_size + 1);
          lseek (fd, 0L, SEEK_SET);
          cmdline[0] = '\0';
          if ((nread = read (fd, cmdline, cmdline_size)) >= 0)
            cmdline[nread++] = '\0';
          else
            {
              /* Assigning zero to `nread' makes us skip the following
                 two loops, assign zero to cmdline_size, and enter the
                 following `if' clause that handles unknown command
                 lines.  */
              nread = 0;
            }
          /* We don't want trailing null characters.  */
          for (p = cmdline + nread - 1; p > cmdline && !*p; p--)
            nread--;
          for (p = cmdline; p < cmdline + nread; p++)
            {
              /* Escape-quote whitespace and backslashes.  */
              if (isspace (*p) || *p == '\\')
                {
                  memmove (p + 1, p, nread - (p - cmdline));
                  nread++;
                  *p++ = '\\';
                }
              else if (*p == '\0')
                *p = ' ';
            }
          cmdline_size = nread;
        }
      if (!cmdline_size)
        {
          if (!cmd)
            cmd = "???";
          if (!cmdsize)
            cmdsize = strlen (cmd);
          cmdline_size = cmdsize + 2;
          cmdline = xmalloc (cmdline_size + 1);
          strcpy (cmdline, "[");
          strcat (strncat (cmdline, cmd, cmdsize), "]");
        }
      emacs_close (fd);
      /* Command line is encoded in locale-coding-system; decode it.  */
      cmd_str = make_unibyte_string (cmdline, cmdline_size);
      decoded_cmd = code_convert_string_norecord (cmd_str,
                                                  Vlocale_coding_system, 0);
      xfree (cmdline);
      attrs = Fcons (Fcons (Qargs, decoded_cmd), attrs);
    }

  UNGCPRO;
  return attrs;
}

#elif defined (SOLARIS2) && defined (HAVE_PROCFS)

/* The <procfs.h> header does not like to be included if _LP64 is defined and
   __FILE_OFFSET_BITS == 64.  This is an ugly workaround that.  */
#if !defined (_LP64) && defined (_FILE_OFFSET_BITS) &&  (_FILE_OFFSET_BITS  ==  64)
#define PROCFS_FILE_OFFSET_BITS_HACK 1
#undef _FILE_OFFSET_BITS
#else
#define PROCFS_FILE_OFFSET_BITS_HACK 0
#endif

#include <procfs.h>

#if PROCFS_FILE_OFFSET_BITS_HACK ==  1
#define _FILE_OFFSET_BITS 64
#endif /* PROCFS_FILE_OFFSET_BITS_HACK ==  1 */

Lisp_Object
system_process_attributes (Lisp_Object pid)
{
  char procfn[PATH_MAX], fn[PATH_MAX];
  struct stat st;
  struct passwd *pw;
  struct group *gr;
  char *procfn_end;
  struct psinfo pinfo;
  int fd;
  ssize_t nread;
  int proc_id, uid, gid;
  Lisp_Object attrs = Qnil;
  Lisp_Object decoded_cmd, tem;
  struct gcpro gcpro1, gcpro2;
  EMACS_INT uid_eint, gid_eint;

  CHECK_NUMBER_OR_FLOAT (pid);
  proc_id = FLOATP (pid) ? XFLOAT_DATA (pid) : XINT (pid);
  sprintf (procfn, "/proc/%u", proc_id);
  if (stat (procfn, &st) < 0)
    return attrs;

  GCPRO2 (attrs, decoded_cmd);

  /* euid egid */
  uid = st.st_uid;
  /* Use of EMACS_INT stops GCC whining about limited range of data type.  */
  uid_eint = uid;
  attrs = Fcons (Fcons (Qeuid, make_fixnum_or_float (uid_eint)), attrs);
  BLOCK_INPUT;
  pw = getpwuid (uid);
  UNBLOCK_INPUT;
  if (pw)
    attrs = Fcons (Fcons (Quser, build_string (pw->pw_name)), attrs);

  gid = st.st_gid;
  gid_eint = gid;
  attrs = Fcons (Fcons (Qegid, make_fixnum_or_float (gid_eint)), attrs);
  BLOCK_INPUT;
  gr = getgrgid (gid);
  UNBLOCK_INPUT;
  if (gr)
    attrs = Fcons (Fcons (Qgroup, build_string (gr->gr_name)), attrs);

  strcpy (fn, procfn);
  procfn_end = fn + strlen (fn);
  strcpy (procfn_end, "/psinfo");
  fd = emacs_open (fn, O_RDONLY, 0);
  if (fd >= 0
      && (nread = read (fd, (char*)&pinfo, sizeof(struct psinfo)) > 0))
    {
          attrs = Fcons (Fcons (Qppid, make_fixnum_or_float (pinfo.pr_ppid)), attrs);
          attrs = Fcons (Fcons (Qpgrp, make_fixnum_or_float (pinfo.pr_pgid)), attrs);
          attrs = Fcons (Fcons (Qsess, make_fixnum_or_float (pinfo.pr_sid)), attrs);

          {
            char state_str[2];
            state_str[0] =  pinfo.pr_lwp.pr_sname;
            state_str[1] =  '\0';
            tem =   build_string (state_str);
            attrs =  Fcons (Fcons (Qstate,  tem),  attrs);
          }

          /* FIXME: missing Qttyname. psinfo.pr_ttydev is a dev_t,
             need to get a string from it. */

          /* FIXME: missing: Qtpgid */

          /* FIXME: missing:
                Qminflt
                Qmajflt
                Qcminflt
                Qcmajflt

                Qutime
                Qcutime
                Qstime
                Qcstime
                Are they available? */

          attrs = Fcons (Fcons (Qtime,
                                list3 (make_number (pinfo.pr_time.tv_sec >> 16),
                                       make_number (pinfo.pr_time.tv_sec & 0xffff),
                                       make_number (pinfo.pr_time.tv_nsec))),
                         attrs);

          attrs = Fcons (Fcons (Qctime,
                                list3 (make_number (pinfo.pr_ctime.tv_sec >> 16),
                                       make_number (pinfo.pr_ctime.tv_sec & 0xffff),
                                       make_number (pinfo.pr_ctime.tv_nsec))),
                         attrs);

          attrs = Fcons (Fcons (Qpri, make_number (pinfo.pr_lwp.pr_pri)), attrs);
          attrs = Fcons (Fcons (Qnice, make_number (pinfo.pr_lwp.pr_nice)), attrs);
          attrs = Fcons (Fcons (Qthcount, make_fixnum_or_float (pinfo.pr_nlwp)), attrs);

          attrs = Fcons (Fcons (Qstart,
                                list3 (make_number (pinfo.pr_start.tv_sec >> 16),
                                       make_number (pinfo.pr_start.tv_sec & 0xffff),
                                       make_number (pinfo.pr_start.tv_nsec))),
                         attrs);
          attrs = Fcons (Fcons (Qvsize, make_fixnum_or_float (pinfo.pr_size)), attrs);
          attrs = Fcons (Fcons (Qrss, make_fixnum_or_float (pinfo.pr_rssize)), attrs);

          /* pr_pctcpu and pr_pctmem are encoded as a fixed point 16 bit number in  [0 ... 1].  */
          attrs = Fcons (Fcons (Qpcpu, (pinfo.pr_pctcpu * 100.0) / (double)0x8000), attrs);
          attrs = Fcons (Fcons (Qpmem, (pinfo.pr_pctmem * 100.0) / (double)0x8000), attrs);

          decoded_cmd
            =  code_convert_string_norecord (make_unibyte_string (pinfo.pr_fname,
                                                                  strlen (pinfo.pr_fname)),
                                             Vlocale_coding_system,  0);
          attrs =  Fcons (Fcons (Qcomm,  decoded_cmd),  attrs);
          decoded_cmd
            =  code_convert_string_norecord (make_unibyte_string (pinfo.pr_psargs,
                                                                  strlen (pinfo.pr_psargs)),
                                             Vlocale_coding_system,  0);
          attrs =  Fcons (Fcons (Qargs,  decoded_cmd),  attrs);
    }

  if (fd >= 0)
    emacs_close (fd);

  UNGCPRO;
  return attrs;
}

/* The WINDOWSNT implementation is in w32.c.
   The MSDOS implementation is in dosfns.c.  */
#elif !defined (WINDOWSNT) && !defined (MSDOS)

Lisp_Object
system_process_attributes (Lisp_Object pid)
{
  return Qnil;
}

#endif  /* !defined (WINDOWSNT) */


/* arch-tag: edb43589-4e09-4544-b325-978b5b121dcf
   (do not change this comment) */