text: /* Low level interface to ptrace, for GDB when running under Unix.
     Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
     1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004
     Free Software Foundation, Inc.
  
     This file is part of GDB.
  
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.
  
     This program 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 this program; if not, write to the Free Software
     Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.  */
  
  #include "defs.h"
  #include "frame.h"
  #include "inferior.h"
  #include "command.h"
  #include "serial.h"
  #include "terminal.h"
  #include "target.h"
  #include "gdbthread.h"
  
  #include "gdb_string.h"
  #include <signal.h>
  #include <fcntl.h>
  #ifdef HAVE_SYS_SELECT_H
  #include <sys/select.h>
  #endif
  
  #include "inflow.h"
  
  #ifdef HAVE_SYS_IOCTL_H
  #include <sys/ioctl.h>
  #endif
  
  #if defined (SIGIO) && defined (FASYNC) && defined (FD_SET) && defined (F_SETOWN)
  static void handle_sigio (int);
  #endif
  
  extern void _initialize_inflow (void);
  
  static void pass_signal (int);
  
  static void kill_command (char *, int);
  
  static void terminal_ours_1 (int);
  
  /* Record terminal status separately for debugger and inferior.  */
  
  static struct serial *stdin_serial;
  
  /* TTY state for the inferior.  We save it whenever the inferior stops, and
     restore it when it resumes.  */
  static serial_ttystate inferior_ttystate;
  
  /* Our own tty state, which we restore every time we need to deal with the
     terminal.  We only set it once, when GDB first starts.  The settings of
     flags which readline saves and restores and unimportant.  */
  static serial_ttystate our_ttystate;
  
  /* fcntl flags for us and the inferior.  Saved and restored just like
     {our,inferior}_ttystate.  */
  static int tflags_inferior;
  static int tflags_ours;
  
  #ifdef PROCESS_GROUP_TYPE
  /* Process group for us and the inferior.  Saved and restored just like
     {our,inferior}_ttystate.  */
  PROCESS_GROUP_TYPE our_process_group;
  PROCESS_GROUP_TYPE inferior_process_group;
  #endif
  
  /* While the inferior is running, we want SIGINT and SIGQUIT to go to the
     inferior only.  If we have job control, that takes care of it.  If not,
     we save our handlers in these two variables and set SIGINT and SIGQUIT
     to SIG_IGN.  */
  
  static void (*sigint_ours) ();
  static void (*sigquit_ours) ();
  
  /* The name of the tty (from the `tty' command) that we gave to the inferior
     when it was last started.  */
  
  static char *inferior_thisrun_terminal;
  
  /* Nonzero if our terminal settings are in effect.  Zero if the
     inferior's settings are in effect.  Ignored if !gdb_has_a_terminal
     ().  */
  
  int terminal_is_ours;
  
  enum
    {
      yes, no, have_not_checked
    }
  gdb_has_a_terminal_flag = have_not_checked;
  
  /* Does GDB have a terminal (on stdin)?  */
  int
  gdb_has_a_terminal (void)
  {
    switch (gdb_has_a_terminal_flag)
      {
      case yes:
        return 1;
      case no:
        return 0;
      case have_not_checked:
        /* Get all the current tty settings (including whether we have a
           tty at all!).  Can't do this in _initialize_inflow because
           serial_fdopen() won't work until the serial_ops_list is
           initialized.  */
  
  #ifdef F_GETFL
        tflags_ours = fcntl (0, F_GETFL, 0);
  #endif
  
        gdb_has_a_terminal_flag = no;
        stdin_serial = serial_fdopen (0);
        if (stdin_serial != NULL)
  	{
  	  our_ttystate = serial_get_tty_state (stdin_serial);
  
  	  if (our_ttystate != NULL)
  	    {
  	      gdb_has_a_terminal_flag = yes;
  #ifdef HAVE_TERMIOS
  	      our_process_group = tcgetpgrp (0);
  #endif
  #ifdef HAVE_TERMIO
  	      our_process_group = getpgrp ();
  #endif
  #ifdef HAVE_SGTTY
  	      ioctl (0, TIOCGPGRP, &our_process_group);
  #endif
  	    }
  	}
  
        return gdb_has_a_terminal_flag == yes;
      default:
        /* "Can't happen".  */
        return 0;
      }
  }
  
  /* Macro for printing errors from ioctl operations */
  
  #define	OOPSY(what)	\
    if (result == -1)	\
      fprintf_unfiltered(gdb_stderr, "[%s failed in terminal_inferior: %s]\n", \
  	    what, safe_strerror (errno))
  
  static void terminal_ours_1 (int);
  
  /* Initialize the terminal settings we record for the inferior,
     before we actually run the inferior.  */
  
  void
  terminal_init_inferior_with_pgrp (int pgrp)
  {
    if (gdb_has_a_terminal ())
      {
        /* We could just as well copy our_ttystate (if we felt like
           adding a new function serial_copy_tty_state()).  */
        if (inferior_ttystate)
  	xfree (inferior_ttystate);
        inferior_ttystate = serial_get_tty_state (stdin_serial);
  
  #ifdef PROCESS_GROUP_TYPE
        inferior_process_group = pgrp;
  #endif
  
        /* Make sure that next time we call terminal_inferior (which will be
           before the program runs, as it needs to be), we install the new
           process group.  */
        terminal_is_ours = 1;
      }
  }
  
  /* Save the terminal settings again.  This is necessary for the TUI
     when it switches to TUI or non-TUI mode;  curses changes the terminal
     and gdb must be able to restore it correctly.  */
  
  void
  terminal_save_ours (void)
  {
    if (gdb_has_a_terminal ())
      {
        /* We could just as well copy our_ttystate (if we felt like adding
           a new function serial_copy_tty_state).  */
        if (our_ttystate)
          xfree (our_ttystate);
        our_ttystate = serial_get_tty_state (stdin_serial);
      }
  }
  
  void
  terminal_init_inferior (void)
  {
  #ifdef PROCESS_GROUP_TYPE
    /* This is for Lynx, and should be cleaned up by having Lynx be a separate
       debugging target with a version of target_terminal_init_inferior which
       passes in the process group to a generic routine which does all the work
       (and the non-threaded child_terminal_init_inferior can just pass in
       inferior_ptid to the same routine).  */
    /* We assume INFERIOR_PID is also the child's process group.  */
    terminal_init_inferior_with_pgrp (PIDGET (inferior_ptid));
  #endif /* PROCESS_GROUP_TYPE */
  }
  
  /* Put the inferior's terminal settings into effect.
     This is preparation for starting or resuming the inferior.  */
  
  void
  terminal_inferior (void)
  {
    if (gdb_has_a_terminal () && terminal_is_ours
        && inferior_ttystate != NULL
        && inferior_thisrun_terminal == 0)
      {
        int result;
  
  #ifdef F_GETFL
        /* Is there a reason this is being done twice?  It happens both
           places we use F_SETFL, so I'm inclined to think perhaps there
           is some reason, however perverse.  Perhaps not though...  */
        result = fcntl (0, F_SETFL, tflags_inferior);
        result = fcntl (0, F_SETFL, tflags_inferior);
        OOPSY ("fcntl F_SETFL");
  #endif
  
        /* Because we were careful to not change in or out of raw mode in
           terminal_ours, we will not change in our out of raw mode with
           this call, so we don't flush any input.  */
        result = serial_set_tty_state (stdin_serial, inferior_ttystate);
        OOPSY ("setting tty state");
  
        if (!job_control)
  	{
  	  sigint_ours = (void (*)()) signal (SIGINT, SIG_IGN);
  #ifdef SIGQUIT
  	  sigquit_ours = (void (*)()) signal (SIGQUIT, SIG_IGN);
  #endif
  	}
  
        /* If attach_flag is set, we don't know whether we are sharing a
           terminal with the inferior or not.  (attaching a process
           without a terminal is one case where we do not; attaching a
           process which we ran from the same shell as GDB via `&' is
           one case where we do, I think (but perhaps this is not
           `sharing' in the sense that we need to save and restore tty
           state)).  I don't know if there is any way to tell whether we
           are sharing a terminal.  So what we do is to go through all
           the saving and restoring of the tty state, but ignore errors
           setting the process group, which will happen if we are not
           sharing a terminal).  */
  
        if (job_control)
  	{
  #ifdef HAVE_TERMIOS
  	  result = tcsetpgrp (0, inferior_process_group);
  	  if (!attach_flag)
  	    OOPSY ("tcsetpgrp");
  #endif
  
  #ifdef HAVE_SGTTY
  	  result = ioctl (0, TIOCSPGRP, &inferior_process_group);
  	  if (!attach_flag)
  	    OOPSY ("TIOCSPGRP");
  #endif
  	}
  
      }
    terminal_is_ours = 0;
  }
  
  /* Put some of our terminal settings into effect,
     enough to get proper results from our output,
     but do not change into or out of RAW mode
     so that no input is discarded.
  
     After doing this, either terminal_ours or terminal_inferior
     should be called to get back to a normal state of affairs.  */
  
  void
  terminal_ours_for_output (void)
  {
    terminal_ours_1 (1);
  }
  
  /* Put our terminal settings into effect.
     First record the inferior's terminal settings
     so they can be restored properly later.  */
  
  void
  terminal_ours (void)
  {
    terminal_ours_1 (0);
  }
  
  /* output_only is not used, and should not be used unless we introduce
     separate terminal_is_ours and terminal_is_ours_for_output
     flags.  */
  
  static void
  terminal_ours_1 (int output_only)
  {
    /* Checking inferior_thisrun_terminal is necessary so that
       if GDB is running in the background, it won't block trying
       to do the ioctl()'s below.  Checking gdb_has_a_terminal
       avoids attempting all the ioctl's when running in batch.  */
    if (inferior_thisrun_terminal != 0 || gdb_has_a_terminal () == 0)
      return;
  
    if (!terminal_is_ours)
      {
  #ifdef SIGTTOU
        /* Ignore this signal since it will happen when we try to set the
           pgrp.  */
        void (*osigttou) () = NULL;
  #endif
        int result;
  
        terminal_is_ours = 1;
  
  #ifdef SIGTTOU
        if (job_control)
  	osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN);
  #endif
  
        if (inferior_ttystate)
  	xfree (inferior_ttystate);
        inferior_ttystate = serial_get_tty_state (stdin_serial);
  #ifdef HAVE_TERMIOS
        inferior_process_group = tcgetpgrp (0);
  #endif
  #ifdef HAVE_TERMIO
        inferior_process_group = getpgrp ();
  #endif
  #ifdef HAVE_SGTTY
        ioctl (0, TIOCGPGRP, &inferior_process_group);
  #endif
  
        /* Here we used to set ICANON in our ttystate, but I believe this
           was an artifact from before when we used readline.  Readline sets
           the tty state when it needs to.
           FIXME-maybe: However, query() expects non-raw mode and doesn't
           use readline.  Maybe query should use readline (on the other hand,
           this only matters for HAVE_SGTTY, not termio or termios, I think).  */
  
        /* Set tty state to our_ttystate.  We don't change in our out of raw
           mode, to avoid flushing input.  We need to do the same thing
           regardless of output_only, because we don't have separate
           terminal_is_ours and terminal_is_ours_for_output flags.  It's OK,
           though, since readline will deal with raw mode when/if it needs to.
         */
  
        serial_noflush_set_tty_state (stdin_serial, our_ttystate,
  				    inferior_ttystate);
  
        if (job_control)
  	{
  #ifdef HAVE_TERMIOS
  	  result = tcsetpgrp (0, our_process_group);
  #if 0
  	  /* This fails on Ultrix with EINVAL if you run the testsuite
  	     in the background with nohup, and then log out.  GDB never
  	     used to check for an error here, so perhaps there are other
  	     such situations as well.  */
  	  if (result == -1)
  	    fprintf_unfiltered (gdb_stderr, "[tcsetpgrp failed in terminal_ours: %s]\n",
  				safe_strerror (errno));
  #endif
  #endif /* termios */
  
  #ifdef HAVE_SGTTY
  	  result = ioctl (0, TIOCSPGRP, &our_process_group);
  #endif
  	}
  
  #ifdef SIGTTOU
        if (job_control)
  	signal (SIGTTOU, osigttou);
  #endif
  
        if (!job_control)
  	{
  	  signal (SIGINT, sigint_ours);
  #ifdef SIGQUIT
  	  signal (SIGQUIT, sigquit_ours);
  #endif
  	}
  
  #ifdef F_GETFL
        tflags_inferior = fcntl (0, F_GETFL, 0);
  
        /* Is there a reason this is being done twice?  It happens both
           places we use F_SETFL, so I'm inclined to think perhaps there
           is some reason, however perverse.  Perhaps not though...  */
        result = fcntl (0, F_SETFL, tflags_ours);
        result = fcntl (0, F_SETFL, tflags_ours);
  #endif
  
        result = result;		/* lint */
      }
  }
  
  void
  term_info (char *arg, int from_tty)
  {
    target_terminal_info (arg, from_tty);
  }
  
  void
  child_terminal_info (char *args, int from_tty)
  {
    if (!gdb_has_a_terminal ())
      {
        printf_filtered ("This GDB does not control a terminal.\n");
        return;
      }
  
    printf_filtered ("Inferior's terminal status (currently saved by GDB):\n");
  
    /* First the fcntl flags.  */
    {
      int flags;
  
      flags = tflags_inferior;
  
      printf_filtered ("File descriptor flags = ");
  
  #ifndef O_ACCMODE
  #define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
  #endif
      /* (O_ACCMODE) parens are to avoid Ultrix header file bug */
      switch (flags & (O_ACCMODE))
        {
        case O_RDONLY:
  	printf_filtered ("O_RDONLY");
  	break;
        case O_WRONLY:
  	printf_filtered ("O_WRONLY");
  	break;
        case O_RDWR:
  	printf_filtered ("O_RDWR");
  	break;
        }
      flags &= ~(O_ACCMODE);
  
  #ifdef O_NONBLOCK
      if (flags & O_NONBLOCK)
        printf_filtered (" | O_NONBLOCK");
      flags &= ~O_NONBLOCK;
  #endif
  
  #if defined (O_NDELAY)
      /* If O_NDELAY and O_NONBLOCK are defined to the same thing, we will
         print it as O_NONBLOCK, which is good cause that is what POSIX
         has, and the flag will already be cleared by the time we get here.  */
      if (flags & O_NDELAY)
        printf_filtered (" | O_NDELAY");
      flags &= ~O_NDELAY;
  #endif
  
      if (flags & O_APPEND)
        printf_filtered (" | O_APPEND");
      flags &= ~O_APPEND;
  
  #if defined (O_BINARY)
      if (flags & O_BINARY)
        printf_filtered (" | O_BINARY");
      flags &= ~O_BINARY;
  #endif
  
      if (flags)
        printf_filtered (" | 0x%x", flags);
      printf_filtered ("\n");
    }
  
  #ifdef PROCESS_GROUP_TYPE
    printf_filtered ("Process group = %d\n",
  		   (int) inferior_process_group);
  #endif
  
    serial_print_tty_state (stdin_serial, inferior_ttystate, gdb_stdout);
  }
  
  /* NEW_TTY_PREFORK is called before forking a new child process,
     so we can record the state of ttys in the child to be formed.
     TTYNAME is null if we are to share the terminal with gdb;
     or points to a string containing the name of the desired tty.
  
     NEW_TTY is called in new child processes under Unix, which will
     become debugger target processes.  This actually switches to
     the terminal specified in the NEW_TTY_PREFORK call.  */
  
  void
  new_tty_prefork (char *ttyname)
  {
    /* Save the name for later, for determining whether we and the child
       are sharing a tty.  */
    inferior_thisrun_terminal = ttyname;
  }
  
  void
  new_tty (void)
  {
    int tty;
  
    if (inferior_thisrun_terminal == 0)
      return;
  #if !defined(__GO32__) && !defined(_WIN32)
  #ifdef TIOCNOTTY
    /* Disconnect the child process from our controlling terminal.  On some
       systems (SVR4 for example), this may cause a SIGTTOU, so temporarily
       ignore SIGTTOU. */
    tty = open ("/dev/tty", O_RDWR);
    if (tty > 0)
      {
        void (*osigttou) ();
  
        osigttou = (void (*)()) signal (SIGTTOU, SIG_IGN);
        ioctl (tty, TIOCNOTTY, 0);
        close (tty);
        signal (SIGTTOU, osigttou);
      }
  #endif
  
    /* Now open the specified new terminal.  */
  
  #ifdef USE_O_NOCTTY
    tty = open (inferior_thisrun_terminal, O_RDWR | O_NOCTTY);
  #else
    tty = open (inferior_thisrun_terminal, O_RDWR);
  #endif
    if (tty == -1)
      {
        print_sys_errmsg (inferior_thisrun_terminal, errno);
        _exit (1);
      }
  
    /* Avoid use of dup2; doesn't exist on all systems.  */
    if (tty != 0)
      {
        close (0);
        dup (tty);
      }
    if (tty != 1)
      {
        close (1);
        dup (tty);
      }
    if (tty != 2)
      {
        close (2);
        dup (tty);
      }
    if (tty > 2)
      close (tty);
  #endif /* !go32 && !win32 */
  }
  
  /* Kill the inferior process.  Make us have no inferior.  */
  
  static void
  kill_command (char *arg, int from_tty)
  {
    /* FIXME:  This should not really be inferior_ptid (or target_has_execution).
       It should be a distinct flag that indicates that a target is active, cuz
       some targets don't have processes! */
  
    if (ptid_equal (inferior_ptid, null_ptid))
      error ("The program is not being run.");
    if (!query ("Kill the program being debugged? "))
      error ("Not confirmed.");
    target_kill ();
  
    init_thread_list ();		/* Destroy thread info */
  
    /* Killing off the inferior can leave us with a core file.  If so,
       print the state we are left in.  */
    if (target_has_stack)
      {
        printf_filtered ("In %s,\n", target_longname);
        if (deprecated_selected_frame == NULL)
  	fputs_filtered ("No selected stack frame.\n", gdb_stdout);
        else
  	print_stack_frame (deprecated_selected_frame,
  			   frame_relative_level (deprecated_selected_frame), 1);
      }
  }
  
  /* Call set_sigint_trap when you need to pass a signal on to an attached
     process when handling SIGINT */
  
  static void
  pass_signal (int signo)
  {
  #ifndef _WIN32
    kill (PIDGET (inferior_ptid), SIGINT);
  #endif
  }
  
  static void (*osig) ();
  
  void
  set_sigint_trap (void)
  {
    if (attach_flag || inferior_thisrun_terminal)
      {
        osig = (void (*)()) signal (SIGINT, pass_signal);
      }
  }
  
  void
  clear_sigint_trap (void)
  {
    if (attach_flag || inferior_thisrun_terminal)
      {
        signal (SIGINT, osig);
      }
  }
  
  #if defined (SIGIO) && defined (FASYNC) && defined (FD_SET) && defined (F_SETOWN)
  static void (*old_sigio) ();
  
  static void
  handle_sigio (int signo)
  {
    int numfds;
    fd_set readfds;
  
    signal (SIGIO, handle_sigio);
  
    FD_ZERO (&readfds);
    FD_SET (target_activity_fd, &readfds);
    numfds = select (target_activity_fd + 1, &readfds, NULL, NULL, NULL);
    if (numfds >= 0 && FD_ISSET (target_activity_fd, &readfds))
      {
  #ifndef _WIN32
        if ((*target_activity_function) ())
  	kill (PIDGET (inferior_ptid), SIGINT);
  #endif
      }
  }
  
  static int old_fcntl_flags;
  
  void
  set_sigio_trap (void)
  {
    if (target_activity_function)
      {
        old_sigio = (void (*)()) signal (SIGIO, handle_sigio);
        fcntl (target_activity_fd, F_SETOWN, getpid ());
        old_fcntl_flags = fcntl (target_activity_fd, F_GETFL, 0);
        fcntl (target_activity_fd, F_SETFL, old_fcntl_flags | FASYNC);
      }
  }
  
  void
  clear_sigio_trap (void)
  {
    if (target_activity_function)
      {
        signal (SIGIO, old_sigio);
        fcntl (target_activity_fd, F_SETFL, old_fcntl_flags);
      }
  }
  #else /* No SIGIO.  */
  void
  set_sigio_trap (void)
  {
    if (target_activity_function)
      internal_error (__FILE__, __LINE__, "failed internal consistency check");
  }
  
  void
  clear_sigio_trap (void)
  {
    if (target_activity_function)
      internal_error (__FILE__, __LINE__, "failed internal consistency check");
  }
  #endif /* No SIGIO.  */
  
  
  /* This is here because this is where we figure out whether we (probably)
     have job control.  Just using job_control only does part of it because
     setpgid or setpgrp might not exist on a system without job control.
     It might be considered misplaced (on the other hand, process groups and
     job control are closely related to ttys).
  
     For a more clean implementation, in libiberty, put a setpgid which merely
     calls setpgrp and a setpgrp which does nothing (any system with job control
     will have one or the other).  */
  int
  gdb_setpgid (void)
  {
    int retval = 0;
  
    if (job_control)
      {
  #if defined (HAVE_TERMIOS) || defined (TIOCGPGRP)
  #ifdef HAVE_SETPGID
        /* The call setpgid (0, 0) is supposed to work and mean the same
           thing as this, but on Ultrix 4.2A it fails with EPERM (and
           setpgid (getpid (), getpid ()) succeeds).  */
        retval = setpgid (getpid (), getpid ());
  #else
  #ifdef HAVE_SETPGRP
  #ifdef SETPGRP_VOID 
        retval = setpgrp ();
  #else
        retval = setpgrp (getpid (), getpid ());
  #endif
  #endif /* HAVE_SETPGRP */
  #endif /* HAVE_SETPGID */
  #endif /* defined (HAVE_TERMIOS) || defined (TIOCGPGRP) */
      }
  
    return retval;
  }
  
  void
  _initialize_inflow (void)
  {
    add_info ("terminal", term_info,
  	    "Print inferior's saved terminal status.");
  
    add_com ("kill", class_run, kill_command,
  	   "Kill execution of program being debugged.");
  
    inferior_ptid = null_ptid;
  
    terminal_is_ours = 1;
  
    /* OK, figure out whether we have job control.  If neither termios nor
       sgtty (i.e. termio or go32), leave job_control 0.  */
  
  #if defined (HAVE_TERMIOS)
    /* Do all systems with termios have the POSIX way of identifying job
       control?  I hope so.  */
  #ifdef _POSIX_JOB_CONTROL
    job_control = 1;
  #else
  #ifdef _SC_JOB_CONTROL
    job_control = sysconf (_SC_JOB_CONTROL);
  #else
    job_control = 0;		/* have to assume the worst */
  #endif /* _SC_JOB_CONTROL */
  #endif /* _POSIX_JOB_CONTROL */
  #endif /* HAVE_TERMIOS */
  
  #ifdef HAVE_SGTTY
  #ifdef TIOCGPGRP
    job_control = 1;
  #else
    job_control = 0;
  #endif /* TIOCGPGRP */
  #endif /* sgtty */
  }
  