external/bsd/less/dist/signal.c

   1 /*      $NetBSD: signal.c,v 1.4 2013/09/04 19:44:21 tron Exp $  */
   2
   3 /*
   4  * Copyright (C) 1984-2012  Mark Nudelman
   5  *
   6  * You may distribute under the terms of either the GNU General Public
   7  * License or the Less License, as specified in the README file.
   8  *
   9  * For more information, see the README file.
  10  */
  11
  12
  13 /*
  14  * Routines dealing with signals.
  15  *
  16  * A signal usually merely causes a bit to be set in the "signals" word.
  17  * At some convenient time, the mainline code checks to see if any
  18  * signals need processing by calling psignal().
  19  * If we happen to be reading from a file [in iread()] at the time
  20  * the signal is received, we call intread to interrupt the iread.
  21  */
  22
  23 #include "less.h"
  24 #include <signal.h>
  25
  26 /*
  27  * "sigs" contains bits indicating signals which need to be processed.
  28  */
  29 public int sigs;
  30
  31 static RETSIGTYPE u_interrupt __P((int));
  32 static RETSIGTYPE stop __P((int));
  33 #if MSDOS_COMPILER==WIN32C
  34 static BOOL WINAPI wbreak_handler __P((DWORD));
  35 #endif
  36
  37 extern int sc_width, sc_height;
  38 extern int screen_trashed;
  39 extern int lnloop;
  40 extern int linenums;
  41 extern int wscroll;
  42 extern int reading;
  43 extern int quit_on_intr;
  44 extern long jump_sline_fraction;
  45
  46 /*
  47  * Interrupt signal handler.
  48  */
  49         /* ARGSUSED*/
  50         static RETSIGTYPE
  51 u_interrupt(type)
  52         int type;
  53 {
  54         bell();
  55 #if OS2
  56         LSIGNAL(SIGINT, SIG_ACK);
  57 #endif
  58         LSIGNAL(SIGINT, u_interrupt);
  59         sigs |= S_INTERRUPT;
  60 #if MSDOS_COMPILER==DJGPPC
  61         /*
  62          * If a keyboard has been hit, it must be Ctrl-C
  63          * (as opposed to Ctrl-Break), so consume it.
  64          * (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
  65          */
  66         if (kbhit())
  67                 getkey();
  68 #endif
  69         if (reading)
  70                 intread(); /* May longjmp */
  71 }
  72
  73 #ifdef SIGTSTP
  74 /*
  75  * "Stop" (^Z) signal handler.
  76  */
  77         /* ARGSUSED*/
  78         static RETSIGTYPE
  79 stop(type)
  80         int type;
  81 {
  82         LSIGNAL(SIGTSTP, stop);
  83         sigs |= S_STOP;
  84         if (reading)
  85                 intread();
  86 }
  87 #endif
  88
  89 #ifdef SIGWINCH
  90 /*
  91  * "Window" change handler
  92  */
  93         /* ARGSUSED*/
  94         public RETSIGTYPE
  95 winch(type)
  96         int type;
  97 {
  98         LSIGNAL(SIGWINCH, winch);
  99         sigs |= S_WINCH;
 100         if (reading)
 101                 intread();
 102 }
 103 #else
 104 #ifdef SIGWIND
 105 /*
 106  * "Window" change handler
 107  */
 108         /* ARGSUSED*/
 109         public RETSIGTYPE
 110 winch(type)
 111         int type;
 112 {
 113         LSIGNAL(SIGWIND, winch);
 114         sigs |= S_WINCH;
 115         if (reading)
 116                 intread();
 117 }
 118 #endif
 119 #endif
 120
 121 #if MSDOS_COMPILER==WIN32C
 122 /*
 123  * Handle CTRL-C and CTRL-BREAK keys.
 124  */
 125 #include "windows.h"
 126
 127         static BOOL WINAPI
 128 wbreak_handler(dwCtrlType)
 129         DWORD dwCtrlType;
 130 {
 131         switch (dwCtrlType)
 132         {
 133         case CTRL_C_EVENT:
 134         case CTRL_BREAK_EVENT:
 135                 sigs |= S_INTERRUPT;
 136                 return (TRUE);
 137         default:
 138                 break;
 139         }
 140         return (FALSE);
 141 }
 142 #endif
 143
 144 /*
 145  * Set up the signal handlers.
 146  */
 147         public void
 148 init_signals(on)
 149         int on;
 150 {
 151         if (on)
 152         {
 153                 /*
 154                  * Set signal handlers.
 155                  */
 156                 (void) LSIGNAL(SIGINT, u_interrupt);
 157 #if MSDOS_COMPILER==WIN32C
 158                 SetConsoleCtrlHandler(wbreak_handler, TRUE);
 159 #endif
 160 #ifdef SIGTSTP
 161                 (void) LSIGNAL(SIGTSTP, stop);
 162 #endif
 163 #ifdef SIGWINCH
 164                 (void) LSIGNAL(SIGWINCH, winch);
 165 #endif
 166 #ifdef SIGWIND
 167                 (void) LSIGNAL(SIGWIND, winch);
 168 #endif
 169 #ifdef SIGQUIT
 170                 (void) LSIGNAL(SIGQUIT, SIG_IGN);
 171 #endif
 172         } else
 173         {
 174                 /*
 175                  * Restore signals to defaults.
 176                  */
 177                 (void) LSIGNAL(SIGINT, SIG_DFL);
 178 #if MSDOS_COMPILER==WIN32C
 179                 SetConsoleCtrlHandler(wbreak_handler, FALSE);
 180 #endif
 181 #ifdef SIGTSTP
 182                 (void) LSIGNAL(SIGTSTP, SIG_DFL);
 183 #endif
 184 #ifdef SIGWINCH
 185                 (void) LSIGNAL(SIGWINCH, SIG_IGN);
 186 #endif
 187 #ifdef SIGWIND
 188                 (void) LSIGNAL(SIGWIND, SIG_IGN);
 189 #endif
 190 #ifdef SIGQUIT
 191                 (void) LSIGNAL(SIGQUIT, SIG_DFL);
 192 #endif
 193         }
 194 }
 195
 196 /*
 197  * Process any signals we have received.
 198  * A received signal cause a bit to be set in "sigs".
 199  */
 200         public void
 201 psignals()
 202 {
 203         register int tsignals;
 204
 205         if ((tsignals = sigs) == 0)
 206                 return;
 207         sigs = 0;
 208
 209 #ifdef SIGTSTP
 210         if (tsignals & S_STOP)
 211         {
 212                 /*
 213                  * Clean up the terminal.
 214                  */
 215 #ifdef SIGTTOU
 216                 LSIGNAL(SIGTTOU, SIG_IGN);
 217 #endif
 218                 clear_bot();
 219                 deinit();
 220                 flush();
 221                 raw_mode(0);
 222 #ifdef SIGTTOU
 223                 LSIGNAL(SIGTTOU, SIG_DFL);
 224 #endif
 225                 LSIGNAL(SIGTSTP, SIG_DFL);
 226                 kill(getpid(), SIGTSTP);
 227                 /*
 228                  * ... Bye bye. ...
 229                  * Hopefully we'll be back later and resume here...
 230                  * Reset the terminal and arrange to repaint the
 231                  * screen when we get back to the main command loop.
 232                  */
 233                 LSIGNAL(SIGTSTP, stop);
 234                 raw_mode(1);
 235                 init();
 236                 screen_trashed = 1;
 237                 tsignals |= S_WINCH;
 238         }
 239 #endif
 240 #ifdef S_WINCH
 241         if (tsignals & S_WINCH)
 242         {
 243                 int old_width, old_height;
 244                 /*
 245                  * Re-execute scrsize() to read the new window size.
 246                  */
 247                 old_width = sc_width;
 248                 old_height = sc_height;
 249                 get_term();
 250                 if (sc_width != old_width || sc_height != old_height)
 251                 {
 252                         wscroll = (sc_height + 1) / 2;
 253                         calc_jump_sline();
 254                         calc_shift_count();
 255                         screen_trashed = 1;
 256                 }
 257         }
 258 #endif
 259         if (tsignals & S_INTERRUPT)
 260         {
 261                 if (quit_on_intr)
 262                         quit(QUIT_INTERRUPT);
 263         }
 264 }