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/* signals.c -- signal handling support for readline. */

/* Copyright (C) 1987-2005 Free Software Foundation, Inc.

   This file is part of the GNU Readline Library, a library for

   reading lines of text with interactive input and history editing.

   The GNU Readline Library is free software; you can redistribute it

   and/or modify it under the terms of the GNU General Public License

   as published by the Free Software Foundation; either version 2, or

   (at your option) any later version.

   The GNU Readline Library 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.

   The GNU General Public License is often shipped with GNU software, and

   is generally kept in a file called COPYING or LICENSE.  If you do not

   have a copy of the license, write to the Free Software Foundation,

   59 Temple Place, Suite 330, Boston, MA 02111 USA. */

#define READLINE_LIBRARY

#if defined (HAVE_CONFIG_H)

#  include <config.h>

#endif

#include <stdio.h>              /* Just for NULL.  Yuck. */

#include <sys/types.h>

#include <signal.h>

#if defined (HAVE_UNISTD_H)

#  include <unistd.h>

#endif /* HAVE_UNISTD_H */

/* System-specific feature definitions and include files. */

#include "rldefs.h"

#if defined (GWINSZ_IN_SYS_IOCTL)

#  include <sys/ioctl.h>

#endif /* GWINSZ_IN_SYS_IOCTL */

#if defined (HANDLE_SIGNALS)

/* Some standard library routines. */

#include "readline.h"

#include "history.h"

#include "rlprivate.h"

#if !defined (RETSIGTYPE)

#  if defined (VOID_SIGHANDLER)

#    define RETSIGTYPE void

#  else

#    define RETSIGTYPE int

#  endif /* !VOID_SIGHANDLER */

#endif /* !RETSIGTYPE */

#if defined (VOID_SIGHANDLER)

#  define SIGHANDLER_RETURN return

#else

#  define SIGHANDLER_RETURN return (0)

#endif

/* This typedef is equivalent to the one for Function; it allows us

   to say SigHandler *foo = signal (SIGKILL, SIG_IGN); */

typedef RETSIGTYPE SigHandler ();

#if defined (HAVE_POSIX_SIGNALS)

typedef struct sigaction sighandler_cxt;

#  define rl_sigaction(s, nh, oh)       sigaction(s, nh, oh)

#else

typedef struct { SigHandler *sa_handler; int sa_mask, sa_flags; } sighandler_cxt;

#  define sigemptyset(m)

#endif /* !HAVE_POSIX_SIGNALS */

#ifndef SA_RESTART

#  define SA_RESTART 0

#endif

static SigHandler *rl_set_sighandler PARAMS((int, SigHandler *, sighandler_cxt *));

static void rl_maybe_set_sighandler PARAMS((int, SigHandler *, sighandler_cxt *));

/* Exported variables for use by applications. */

/* If non-zero, readline will install its own signal handlers for

   SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP, SIGTTIN, and SIGTTOU. */

int rl_catch_signals = 1;

/* If non-zero, readline will install a signal handler for SIGWINCH. */

#ifdef SIGWINCH

int rl_catch_sigwinch = 1;

#else

int rl_catch_sigwinch = 0;       /* for the readline state struct in readline.c */

#endif

static int signals_set_flag;

static int sigwinch_set_flag;

/* **************************************************************** */

/*                                                                  */

/*                         Signal Handling                          */

/*                                                                  */

/* **************************************************************** */

static sighandler_cxt old_int, old_term, old_alrm, old_quit;

#if defined (SIGTSTP)

static sighandler_cxt old_tstp, old_ttou, old_ttin;

#endif

#if defined (SIGWINCH)

static sighandler_cxt old_winch;

#endif

/* Readline signal handler functions. */

static RETSIGTYPE

rl_signal_handler (sig)

     int sig;

{

#if defined (HAVE_POSIX_SIGNALS)

  sigset_t set;

#else /* !HAVE_POSIX_SIGNALS */

#  if defined (HAVE_BSD_SIGNALS)

  long omask;

#  else /* !HAVE_BSD_SIGNALS */

  sighandler_cxt dummy_cxt;     /* needed for rl_set_sighandler call */

#  endif /* !HAVE_BSD_SIGNALS */

#endif /* !HAVE_POSIX_SIGNALS */

  RL_SETSTATE(RL_STATE_SIGHANDLER);

#if !defined (HAVE_BSD_SIGNALS) && !defined (HAVE_POSIX_SIGNALS)

  /* Since the signal will not be blocked while we are in the signal

     handler, ignore it until rl_clear_signals resets the catcher. */

#  if defined (SIGALRM)

  if (sig == SIGINT || sig == SIGALRM)

#  else

  if (sig == SIGINT)

#  endif

    rl_set_sighandler (sig, SIG_IGN, &dummy_cxt);

#endif /* !HAVE_BSD_SIGNALS && !HAVE_POSIX_SIGNALS */

  switch (sig)

    {

    case SIGINT:

      rl_free_line_state ();

      /* FALLTHROUGH */

    case SIGTERM:

#if defined (SIGTSTP)

    case SIGTSTP:

    case SIGTTOU:

    case SIGTTIN:

#endif /* SIGTSTP */

#if defined (SIGALRM)

    case SIGALRM:

#endif

#if defined (SIGQUIT)

    case SIGQUIT:

#endif

      rl_cleanup_after_signal ();

#if defined (HAVE_POSIX_SIGNALS)

      sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &set);

      sigdelset (&set, sig);

#else /* !HAVE_POSIX_SIGNALS */

#  if defined (HAVE_BSD_SIGNALS)

      omask = sigblock (0);

#  endif /* HAVE_BSD_SIGNALS */

#endif /* !HAVE_POSIX_SIGNALS */

#if defined (__EMX__)

      signal (sig, SIG_ACK);

#endif

#if defined (HAVE_KILL)

      kill (getpid (), sig);

#else

      raise (sig);              /* assume we have raise */

#endif

      /* Let the signal that we just sent through.  */

#if defined (HAVE_POSIX_SIGNALS)

      sigprocmask (SIG_SETMASK, &set, (sigset_t *)NULL);

#else /* !HAVE_POSIX_SIGNALS */

#  if defined (HAVE_BSD_SIGNALS)

      sigsetmask (omask & ~(sigmask (sig)));

#  endif /* HAVE_BSD_SIGNALS */

#endif /* !HAVE_POSIX_SIGNALS */

      rl_reset_after_signal ();

    }

  RL_UNSETSTATE(RL_STATE_SIGHANDLER);

  SIGHANDLER_RETURN;

}

#if defined (SIGWINCH)

static RETSIGTYPE

rl_sigwinch_handler (sig)

     int sig;

{

  SigHandler *oh;

#if defined (MUST_REINSTALL_SIGHANDLERS)

  sighandler_cxt dummy_winch;

  /* We don't want to change old_winch -- it holds the state of SIGWINCH

     disposition set by the calling application.  We need this state

     because we call the application's SIGWINCH handler after updating

     our own idea of the screen size. */

  rl_set_sighandler (SIGWINCH, rl_sigwinch_handler, &dummy_winch);

#endif

  RL_SETSTATE(RL_STATE_SIGHANDLER);

  rl_resize_terminal ();

  /* If another sigwinch handler has been installed, call it. */

  oh = (SigHandler *)old_winch.sa_handler;

  if (oh &&  oh != (SigHandler *)SIG_IGN && oh != (SigHandler *)SIG_DFL)

    (*oh) (sig);

  RL_UNSETSTATE(RL_STATE_SIGHANDLER);

  SIGHANDLER_RETURN;

}

#endif  /* SIGWINCH */

/* Functions to manage signal handling. */

#if !defined (HAVE_POSIX_SIGNALS)

static int

rl_sigaction (sig, nh, oh)

     int sig;

     sighandler_cxt *nh, *oh;

{

  oh->sa_handler = signal (sig, nh->sa_handler);

  return 0;

}

#endif /* !HAVE_POSIX_SIGNALS */

/* Set up a readline-specific signal handler, saving the old signal

   information in OHANDLER.  Return the old signal handler, like

   signal(). */

static SigHandler *

rl_set_sighandler (sig, handler, ohandler)

     int sig;

     SigHandler *handler;

     sighandler_cxt *ohandler;

{

  sighandler_cxt old_handler;

#if defined (HAVE_POSIX_SIGNALS)

  struct sigaction act;

  act.sa_handler = handler;

  act.sa_flags = (sig == SIGWINCH) ? SA_RESTART : 0;

  sigemptyset (&act.sa_mask);

  sigemptyset (&ohandler->sa_mask);

  sigaction (sig, &act, &old_handler);

#else

  old_handler.sa_handler = (SigHandler *)signal (sig, handler);

#endif /* !HAVE_POSIX_SIGNALS */

  /* XXX -- assume we have memcpy */

  /* If rl_set_signals is called twice in a row, don't set the old handler to

     rl_signal_handler, because that would cause infinite recursion. */

  if (handler != rl_signal_handler || old_handler.sa_handler != rl_signal_handler)

    memcpy (ohandler, &old_handler, sizeof (sighandler_cxt));

  return (ohandler->sa_handler);

}

static void

rl_maybe_set_sighandler (sig, handler, ohandler)

     int sig;

     SigHandler *handler;

     sighandler_cxt *ohandler;

{

  sighandler_cxt dummy;

  SigHandler *oh;

  sigemptyset (&dummy.sa_mask);

  oh = rl_set_sighandler (sig, handler, ohandler);

  if (oh == (SigHandler *)SIG_IGN)

    rl_sigaction (sig, ohandler, &dummy);

}

int

rl_set_signals ()

{

  sighandler_cxt dummy;

  SigHandler *oh;

  if (rl_catch_signals && signals_set_flag == 0)

    {

      rl_maybe_set_sighandler (SIGINT, rl_signal_handler, &old_int);

      rl_maybe_set_sighandler (SIGTERM, rl_signal_handler, &old_term);

#if defined (SIGQUIT)

      rl_maybe_set_sighandler (SIGQUIT, rl_signal_handler, &old_quit);

#endif

#if defined (SIGALRM)

      oh = rl_set_sighandler (SIGALRM, rl_signal_handler, &old_alrm);

      if (oh == (SigHandler *)SIG_IGN)

        rl_sigaction (SIGALRM, &old_alrm, &dummy);

#if defined (HAVE_POSIX_SIGNALS) && defined (SA_RESTART)

      /* If the application using readline has already installed a signal

         handler with SA_RESTART, SIGALRM will cause reads to be restarted

         automatically, so readline should just get out of the way.  Since

         we tested for SIG_IGN above, we can just test for SIG_DFL here. */

      if (oh != (SigHandler *)SIG_DFL && (old_alrm.sa_flags & SA_RESTART))

        rl_sigaction (SIGALRM, &old_alrm, &dummy);

#endif /* HAVE_POSIX_SIGNALS */

#endif /* SIGALRM */

#if defined (SIGTSTP)

      rl_maybe_set_sighandler (SIGTSTP, rl_signal_handler, &old_tstp);

#endif /* SIGTSTP */

#if defined (SIGTTOU)

      rl_maybe_set_sighandler (SIGTTOU, rl_signal_handler, &old_ttou);

#endif /* SIGTTOU */

#if defined (SIGTTIN)

      rl_maybe_set_sighandler (SIGTTIN, rl_signal_handler, &old_ttin);

#endif /* SIGTTIN */

      signals_set_flag = 1;

    }

#if defined (SIGWINCH)

  if (rl_catch_sigwinch && sigwinch_set_flag == 0)

    {

      rl_maybe_set_sighandler (SIGWINCH, rl_sigwinch_handler, &old_winch);

      sigwinch_set_flag = 1;

    }

#endif /* SIGWINCH */

  return 0;

}

int

rl_clear_signals ()

{

  sighandler_cxt dummy;

  if (rl_catch_signals && signals_set_flag == 1)

    {

      sigemptyset (&dummy.sa_mask);

      rl_sigaction (SIGINT, &old_int, &dummy);

      rl_sigaction (SIGTERM, &old_term, &dummy);

#if defined (SIGQUIT)

      rl_sigaction (SIGQUIT, &old_quit, &dummy);

#endif

#if defined (SIGALRM)

      rl_sigaction (SIGALRM, &old_alrm, &dummy);

#endif

#if defined (SIGTSTP)

      rl_sigaction (SIGTSTP, &old_tstp, &dummy);

#endif /* SIGTSTP */

#if defined (SIGTTOU)

      rl_sigaction (SIGTTOU, &old_ttou, &dummy);

#endif /* SIGTTOU */

#if defined (SIGTTIN)

      rl_sigaction (SIGTTIN, &old_ttin, &dummy);

#endif /* SIGTTIN */

      signals_set_flag = 0;

    }

#if defined (SIGWINCH)

  if (rl_catch_sigwinch && sigwinch_set_flag == 1)

    {

      sigemptyset (&dummy.sa_mask);

      rl_sigaction (SIGWINCH, &old_winch, &dummy);

      sigwinch_set_flag = 0;

    }

#endif

  return 0;

}

/* Clean up the terminal and readline state after catching a signal, before

   resending it to the calling application. */

void

rl_cleanup_after_signal ()

{

  _rl_clean_up_for_exit ();

  if (rl_deprep_term_function)

    (*rl_deprep_term_function) ();

  rl_clear_signals ();

  rl_clear_pending_input ();

}

/* Reset the terminal and readline state after a signal handler returns. */

void

rl_reset_after_signal ()

{

  if (rl_prep_term_function)

    (*rl_prep_term_function) (_rl_meta_flag);

  rl_set_signals ();

}

/* Free up the readline variable line state for the current line (undo list,

   any partial history entry, any keyboard macros in progress, and any

   numeric arguments in process) after catching a signal, before calling

   rl_cleanup_after_signal(). */

void

rl_free_line_state ()

{

  register HIST_ENTRY *entry;

  rl_free_undo_list ();

  entry = current_history ();

  if (entry)

    entry->data = (char *)NULL;

  _rl_kill_kbd_macro ();

  rl_clear_message ();

  _rl_reset_argument ();

}

#endif  /* HANDLE_SIGNALS */