/* signal.c: signal and miscellaneous routines for the ed line editor. */

/*  GNU ed - The GNU line editor.

    Copyright (C) 1993, 1994 Andrew Moore, Talke Studio

    Copyright (C) 2006-2017 Antonio Diaz Diaz.

    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, see <http://www.gnu.org/licenses/>.

*/

#include <ctype.h>

#include <errno.h>

#include <limits.h>

#include <setjmp.h>

#include <signal.h>

#include <stdlib.h>

#include <string.h>

#include <termios.h>

#include <unistd.h>

#include <sys/ioctl.h>

#include "ed.h"

jmp_buf jmp_state;

static int mutex = 0;			/* If > 0, signals stay pending */

static int window_lines_ = 22;		/* scroll lines set by sigwinch_handler */

static int window_columns_ = 72;

static bool sighup_pending = false;

static bool sigint_pending = false;

static void sighup_handler( int signum )

  {

  if( signum ) {}			/* keep compiler happy */

  if( mutex ) sighup_pending = true;

  else

    {

    const char hb[] = "ed.hup";

    sighup_pending = false;

    if( last_addr() && modified() &&

        write_file( hb, "w", 1, last_addr() ) < 0 )

      {

      char * const s = getenv( "HOME" );

      const int len = ( s ? strlen( s ) : 0 );

      const int need_slash = ( ( !len || s[len-1] != '/' ) ? 1 : 0 );

      char * const hup = ( ( len + need_slash + (int)sizeof hb < path_max( 0 ) ) ?

                    (char *) malloc( len + need_slash + sizeof hb ) : 0 );

      if( len && hup )			/* hup filename */

        {

        memcpy( hup, s, len );

        if( need_slash ) hup[len] = '/';

        memcpy( hup + len + need_slash, hb, sizeof hb );

        if( write_file( hup, "w", 1, last_addr() ) >= 0 ) exit( 0 );

        }

      exit( 1 );			/* hup file write failed */

      }

    exit( 0 );

    }

  }

static void sigint_handler( int signum )

  {

  if( mutex ) sigint_pending = true;

  else

    {

    sigset_t set;

    sigint_pending = false;

    sigemptyset( &set );

    sigaddset( &set, signum );

    sigprocmask( SIG_UNBLOCK, &set, 0 );

    longjmp( jmp_state, -1 );

    }

  }

static void sigwinch_handler( int signum )

  {

#ifdef TIOCGWINSZ

  struct winsize ws;			/* window size structure */

  if( ioctl( 0, TIOCGWINSZ, (char *) &ws ) >= 0 )

    {

    /* Sanity check values of environment vars */

    if( ws.ws_row > 2 && ws.ws_row < 600 ) window_lines_ = ws.ws_row - 2;

    if( ws.ws_col > 8 && ws.ws_col < 1800 ) window_columns_ = ws.ws_col - 8;

    }

#endif

  if( signum ) {}			/* keep compiler happy */

  }

static int set_signal( const int signum, void (*handler)( int ) )

  {

  struct sigaction new_action;

  new_action.sa_handler = handler;

  sigemptyset( &new_action.sa_mask );

#ifdef SA_RESTART

  new_action.sa_flags = SA_RESTART;

#else

  new_action.sa_flags = 0;

#endif

  return sigaction( signum, &new_action, 0 );

  }

void enable_interrupts( void )

  {

  if( --mutex <= 0 )

    {

    mutex = 0;

    if( sighup_pending ) sighup_handler( SIGHUP );

    if( sigint_pending ) sigint_handler( SIGINT );

    }

  }

void disable_interrupts( void ) { ++mutex; }

void set_signals( void )

  {

#ifdef SIGWINCH

  sigwinch_handler( SIGWINCH );

  if( isatty( 0 ) ) set_signal( SIGWINCH, sigwinch_handler );

#endif

  set_signal( SIGHUP, sighup_handler );

  set_signal( SIGQUIT, SIG_IGN );

  set_signal( SIGINT, sigint_handler );

  }

void set_window_lines( const int lines ) { window_lines_ = lines; }

int window_columns( void ) { return window_columns_; }

int window_lines( void ) { return window_lines_; }

/* convert a string to int with out_of_range detection */

bool parse_int( int * const i, const char * const str, const char ** const tail )

  {

  char * tmp;

  long li;

  errno = 0;

  *i = li = strtol( str, &tmp, 10 );

  if( tail ) *tail = tmp;

  if( tmp == str )

    {

    set_error_msg( "Bad numerical result" );

    *i = 0;

    return false;

    }

  if( errno == ERANGE || li > INT_MAX || li < -INT_MAX )

    {

    set_error_msg( "Numerical result out of range" );

    *i = 0;

    return false;

    }

  return true;

  }

/* assure at least a minimum size for buffer 'buf' */

bool resize_buffer( char ** const buf, int * const size, const int min_size )

  {

  if( *size < min_size )

    {

    const int new_size = ( min_size < 512 ? 512 : ( min_size / 512 ) * 1024 );

    void * new_buf = 0;

    disable_interrupts();

    if( *buf ) new_buf = realloc( *buf, new_size );

    else new_buf = malloc( new_size );

    if( !new_buf )

      {

      show_strerror( 0, errno );

      set_error_msg( "Memory exhausted" );

      enable_interrupts();

      return false;

      }

    *size = new_size;

    *buf = (char *)new_buf;

    enable_interrupts();

    }

  return true;

  }

/* assure at least a minimum size for buffer 'buf' */

bool resize_line_buffer( const line_t *** const buf, int * const size,

                         const int min_size )

  {

  if( *size < min_size )

    {

    const int new_size = ( min_size < 512 ? 512 : ( min_size / 512 ) * 1024 );

    void * new_buf = 0;

    disable_interrupts();

    if( *buf ) new_buf = realloc( *buf, new_size );

    else new_buf = malloc( new_size );

    if( !new_buf )

      {

      show_strerror( 0, errno );

      set_error_msg( "Memory exhausted" );

      enable_interrupts();

      return false;

      }

    *size = new_size;

    *buf = (const line_t **)new_buf;

    enable_interrupts();

    }

  return true;

  }

/* assure at least a minimum size for buffer 'buf' */

bool resize_undo_buffer( undo_t ** const buf, int * const size,

                         const int min_size )

  {

  if( *size < min_size )

    {

    const int new_size = ( min_size < 512 ? 512 : ( min_size / 512 ) * 1024 );

    void * new_buf = 0;

    disable_interrupts();

    if( *buf ) new_buf = realloc( *buf, new_size );

    else new_buf = malloc( new_size );

    if( !new_buf )

      {

      show_strerror( 0, errno );

      set_error_msg( "Memory exhausted" );

      enable_interrupts();

      return false;

      }

    *size = new_size;

    *buf = (undo_t *)new_buf;

    enable_interrupts();

    }

  return true;

  }

/* return unescaped copy of escaped string */

const char * strip_escapes( const char * p )

  {

  static char * buf = 0;

  static int bufsz = 0;

  const int len = strlen( p );

  int i = 0;

  if( !resize_buffer( &buf, &bufsz, len + 1 ) ) return 0;

  /* assert: no trailing escape */

  while( ( buf[i++] = ( (*p == '\\' ) ? *++p : *p ) ) )

    ++p;

  return buf;

  }