path: root/gdb/inflow.c

/* Low level interface to ptrace, for GDB when running under Unix.
   Copyright (C) 1986, 1987, 1989 Free Software Foundation, Inc.

This file is part of GDB.

GDB 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 1, or (at your option)
any later version.

GDB 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 GDB; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "defs.h"
#include "param.h"
#include "frame.h"
#include "inferior.h"

#ifdef USG
#include <sys/types.h>
#include <fcntl.h>
#endif

#include <stdio.h>
#include <sys/param.h>
#include <sys/dir.h>
#include <signal.h>

#ifdef HAVE_TERMIO
#include <termio.h>
#undef TIOCGETP
#define TIOCGETP TCGETA
#undef TIOCSETN
#define TIOCSETN TCSETA
#undef TIOCSETP
#define TIOCSETP TCSETAF
#define TERMINAL struct termio
#else
#include <sys/ioctl.h>
#include <fcntl.h>
#include <sgtty.h>
#define TERMINAL struct sgttyb
#endif

#ifdef SET_STACK_LIMIT_HUGE
#include <sys/time.h>
#include <sys/resource.h>
extern int original_stack_limit;
#endif /* SET_STACK_LIMIT_HUGE */

extern int errno;

/* Nonzero if we are debugging an attached outside process
   rather than an inferior.  */

int attach_flag;


/* Record terminal status separately for debugger and inferior.  */

static TERMINAL sg_inferior;
static TERMINAL sg_ours;

static int tflags_inferior;
static int tflags_ours;

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
static struct tchars tc_inferior;
static struct tchars tc_ours;
#endif

#ifdef TIOCGLTC
static struct ltchars ltc_inferior;
static struct ltchars ltc_ours;
#endif

#ifdef TIOCLGET
static int lmode_inferior;
static int lmode_ours;
#endif

#ifdef TIOCGPGRP
static int pgrp_inferior;
static int pgrp_ours;
#else
static int (*sigint_ours) ();
static int (*sigquit_ours) ();
#endif /* TIOCGPGRP */

/* Copy of inferior_io_terminal when inferior was last started.  */
static char *inferior_thisrun_terminal;

static void terminal_ours_1 ();

/* Nonzero if our terminal settings are in effect.
   Zero if the inferior's settings are in effect.  */
static int terminal_is_ours;

/* Initialize the terminal settings we record for the inferior,
   before we actually run the inferior.  */

void
terminal_init_inferior ()
{
  if (remote_debugging)
    return;

  sg_inferior = sg_ours;
  tflags_inferior = tflags_ours;

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
  tc_inferior = tc_ours;
#endif

#ifdef TIOCGLTC
  ltc_inferior = ltc_ours;
#endif

#ifdef TIOCLGET
  lmode_inferior = lmode_ours;
#endif

#ifdef TIOCGPGRP
  pgrp_inferior = inferior_pid;
#endif /* TIOCGPGRP */

  terminal_is_ours = 1;
}

/* Put the inferior's terminal settings into effect.
   This is preparation for starting or resuming the inferior.  */

void
terminal_inferior ()
{
  if (remote_debugging)
    return;

  if (terminal_is_ours)   /*  && inferior_thisrun_terminal == 0) */
    {
      fcntl (0, F_SETFL, tflags_inferior);
      fcntl (0, F_SETFL, tflags_inferior);
      ioctl (0, TIOCSETN, &sg_inferior);

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
      ioctl (0, TIOCSETC, &tc_inferior);
#endif
#ifdef TIOCGLTC
      ioctl (0, TIOCSLTC, &ltc_inferior);
#endif
#ifdef TIOCLGET
      ioctl (0, TIOCLSET, &lmode_inferior);
#endif

#ifdef TIOCGPGRP
      ioctl (0, TIOCSPGRP, &pgrp_inferior);
#else
      sigint_ours = (int (*) ()) signal (SIGINT, SIG_IGN);
      sigquit_ours = (int (*) ()) signal (SIGQUIT, SIG_IGN);
#endif /* TIOCGPGRP */
    }
  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 ()
{
  if (remote_debugging)
    return;

  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 ()
{
  if (remote_debugging)
    return;

  terminal_ours_1 (0);
}

static void
terminal_ours_1 (output_only)
     int output_only;
{
#ifdef TIOCGPGRP
  /* Ignore this signal since it will happen when we try to set the pgrp.  */
  int (*osigttou) ();
#endif /* TIOCGPGRP */

  if (!terminal_is_ours)  /*   && inferior_thisrun_terminal == 0)  */
    {
      terminal_is_ours = 1;

#ifdef TIOCGPGRP
      osigttou = (int (*) ()) signal (SIGTTOU, SIG_IGN);

      ioctl (0, TIOCGPGRP, &pgrp_inferior);
      ioctl (0, TIOCSPGRP, &pgrp_ours);

      signal (SIGTTOU, osigttou);
#else
      signal (SIGINT, sigint_ours);
      signal (SIGQUIT, sigquit_ours);
#endif /* TIOCGPGRP */

      tflags_inferior = fcntl (0, F_GETFL, 0);
      ioctl (0, TIOCGETP, &sg_inferior);

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
      ioctl (0, TIOCGETC, &tc_inferior);
#endif
#ifdef TIOCGLTC
      ioctl (0, TIOCGLTC, &ltc_inferior);
#endif
#ifdef TIOCLGET
      ioctl (0, TIOCLGET, &lmode_inferior);
#endif
    }

#ifdef HAVE_TERMIO
  sg_ours.c_lflag |= ICANON;
  if (output_only && !(sg_inferior.c_lflag & ICANON))
    sg_ours.c_lflag &= ~ICANON;
#else /* not HAVE_TERMIO */
  sg_ours.sg_flags &= ~RAW & ~CBREAK;
  if (output_only)
    sg_ours.sg_flags |= (RAW | CBREAK) & sg_inferior.sg_flags;
#endif /* not HAVE_TERMIO */

  fcntl (0, F_SETFL, tflags_ours);
  fcntl (0, F_SETFL, tflags_ours);
  ioctl (0, TIOCSETN, &sg_ours);

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
  ioctl (0, TIOCSETC, &tc_ours);
#endif
#ifdef TIOCGLTC
  ioctl (0, TIOCSLTC, &ltc_ours);
#endif
#ifdef TIOCLGET
  ioctl (0, TIOCLSET, &lmode_ours);
#endif

#ifdef HAVE_TERMIO
  sg_ours.c_lflag |= ICANON;
#else /* not HAVE_TERMIO */
  sg_ours.sg_flags &= ~RAW & ~CBREAK;
#endif /* not HAVE_TERMIO */
}

static void
term_status_command ()
{
  register int i;

  if (remote_debugging)
    {
      printf_filtered ("No terminal status when remote debugging.\n");
      return;
    }

  printf_filtered ("Inferior's terminal status (currently saved by GDB):\n");

#ifdef HAVE_TERMIO

  printf_filtered ("fcntl flags = 0x%x, c_iflag = 0x%x, c_oflag = 0x%x,\n",
	  tflags_inferior, sg_inferior.c_iflag, sg_inferior.c_oflag);
  printf_filtered ("c_cflag = 0x%x, c_lflag = 0x%x, c_line = 0x%x.\n",
	  sg_inferior.c_cflag, sg_inferior.c_lflag, sg_inferior.c_line);
  printf_filtered ("c_cc: ");
  for (i = 0; (i < NCC); i += 1)
    printf_filtered ("0x%x ", sg_inferior.c_cc[i]);
  printf_filtered ("\n");

#else /* not HAVE_TERMIO */

  printf_filtered ("fcntl flags = 0x%x, sgttyb.sg_flags = 0x%x, owner pid = %d.\n",
	  tflags_inferior, sg_inferior.sg_flags, pgrp_inferior);

#endif /* not HAVE_TERMIO */

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
  printf_filtered ("tchars: ");
  for (i = 0; i < sizeof (struct tchars); i++)
    printf_filtered ("0x%x ", ((char *)&tc_inferior)[i]);
  printf_filtered ("\n");
#endif

#ifdef TIOCGLTC
  printf_filtered ("ltchars: ");
  for (i = 0; i < sizeof (struct ltchars); i++)
    printf_filtered ("0x%x ", ((char *)&ltc_inferior)[i]);
  printf_filtered ("\n");
  ioctl (0, TIOCSLTC, &ltc_ours);
#endif
  
#ifdef TIOCLGET
  printf_filtered ("lmode:  %x\n", lmode_inferior);
#endif
}

static void
new_tty (ttyname)
     char *ttyname;
{
  register int tty;
  register int fd;

#ifdef TIOCNOTTY
  /* Disconnect the child process from our controlling terminal.  */
  tty = open("/dev/tty", O_RDWR);
  if (tty > 0)
    {
      ioctl(tty, TIOCNOTTY, 0);
      close(tty);
    }
#endif

  /* Now open the specified new terminal.  */

  tty = open(ttyname, O_RDWR);
  if (tty == -1)
    _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);
}

/* Start an inferior process and returns its pid.
   ALLARGS is a string containing shell command to run the program.
   ENV is the environment vector to pass.  */

#ifndef SHELL_FILE
#define SHELL_FILE "/bin/sh"
#endif

int
create_inferior (allargs, env)
     char *allargs;
     char **env;
{
  int pid;
  char *shell_command;
  extern int sys_nerr;
  extern char *sys_errlist[];
  extern int errno;

  /* If desired, concat something onto the front of ALLARGS.
     SHELL_COMMAND is the result.  */
#ifdef SHELL_COMMAND_CONCAT
  shell_command = (char *) alloca (strlen (SHELL_COMMAND_CONCAT) + strlen (allargs) + 1);
  strcpy (shell_command, SHELL_COMMAND_CONCAT);
  strcat (shell_command, allargs);
#else
  shell_command = allargs;
#endif

  /* exec is said to fail if the executable is open.  */
  close_exec_file ();

#if defined(USG) && !defined(HAVE_VFORK)
  pid = fork ();
#else
  pid = vfork ();
#endif

  if (pid < 0)
    perror_with_name ("vfork");

  if (pid == 0)
    {
#ifdef TIOCGPGRP
      /* Run inferior in a separate process group.  */
      setpgrp (getpid (), getpid ());
#endif /* TIOCGPGRP */

#ifdef SET_STACK_LIMIT_HUGE
      /* Reset the stack limit back to what it was.  */
      {
	struct rlimit rlim;

	getrlimit (RLIMIT_STACK, &rlim);
	rlim.rlim_cur = original_stack_limit;
	setrlimit (RLIMIT_STACK, &rlim);
      }
#endif /* SET_STACK_LIMIT_HUGE */


      inferior_thisrun_terminal = inferior_io_terminal;
      if (inferior_io_terminal != 0)
	new_tty (inferior_io_terminal);

/* It seems that changing the signal handlers for the inferior after
   a vfork also changes them for the superior.  See comments in
   initialize_signals for how we get the right signal handlers
   for the inferior.  */
/* Not needed on Sun, at least, and loses there
   because it clobbers the superior.  */
/*???      signal (SIGQUIT, SIG_DFL);
      signal (SIGINT, SIG_DFL);  */

      call_ptrace (0);
      execle (SHELL_FILE, "sh", "-c", shell_command, 0, env);

      fprintf (stderr, "Cannot exec %s: %s.\n", SHELL_FILE,
	       errno < sys_nerr ? sys_errlist[errno] : "unknown error");
      fflush (stderr);
      _exit (0177);
    }

#ifdef CREATE_INFERIOR_HOOK
  CREATE_INFERIOR_HOOK (pid);
#endif  
  return pid;
}

/* Kill the inferior process.  Make us have no inferior.  */

static void
kill_command ()
{
  if (remote_debugging)
    return;
  if (inferior_pid == 0)
    error ("The program is not being run.");
  if (!query ("Kill the inferior process? "))
    error ("Not confirmed.");
  kill_inferior ();
}

void
inferior_died ()
{
  inferior_pid = 0;
  attach_flag = 0;
  mark_breakpoints_out ();
  select_frame ((FRAME) 0, -1);
  reopen_exec_file ();
  if (have_core_file_p ())
    set_current_frame ( create_new_frame (read_register (FP_REGNUM),
					  read_pc ()));
  else
    set_current_frame (0);
}

static void
try_writing_regs_command ()
{
  register int i;
  register int value;
  extern int errno;

  if (inferior_pid == 0)
    error ("There is no inferior process now.");

  for (i = 0; ; i += 2)
    {
      QUIT;
      errno = 0;
      value = call_ptrace (3, inferior_pid, i, 0);
      call_ptrace (6, inferior_pid, i, value);
      if (errno == 0)
	{
	  printf (" Succeeded with address 0x%x; value 0x%x (%d).\n",
		  i, value, value);
	}
      else if ((i & 0377) == 0)
	printf (" Failed at 0x%x.\n", i);
    }
}

void
_initialize_inflow ()
{
  add_com ("term-status", class_obscure, term_status_command,
	   "Print info on inferior's saved terminal status.");

  add_com ("try-writing-regs", class_obscure, try_writing_regs_command,
	   "Try writing all locations in inferior's system block.\n\
Report which ones can be written.");

  add_com ("kill", class_run, kill_command,
	   "Kill execution of program being debugged.");

  inferior_pid = 0;

  ioctl (0, TIOCGETP, &sg_ours);
  fcntl (0, F_GETFL, tflags_ours);

#if defined(TIOCGETC) && !defined(TIOCGETC_BROKEN)
  ioctl (0, TIOCGETC, &tc_ours);
#endif
#ifdef TIOCGLTC
  ioctl (0, TIOCGLTC, &ltc_ours);
#endif
#ifdef TIOCLGET
  ioctl (0, TIOCLGET, &lmode_ours);
#endif

#ifdef TIOCGPGRP
  ioctl (0, TIOCGPGRP, &pgrp_ours);
#endif /* TIOCGPGRP */

  terminal_is_ours = 1;
}