contrib/less-403/signal.c

   1 /*
   2  * Copyright (C) 1984-2007  Mark Nudelman
   3  *
   4  * You may distribute under the terms of either the GNU General Public
   5  * License or the Less License, as specified in the README file.
   6  *
   7  * For more information about less, or for information on how to
   8  * contact the author, see the README file.
   9  */
  10
  11
  12 /*
  13  * Routines dealing with signals.
  14  *
  15  * A signal usually merely causes a bit to be set in the "signals" word.
  16  * At some convenient time, the mainline code checks to see if any
  17  * signals need processing by calling psignal().
  18  * If we happen to be reading from a file [in iread()] at the time
  19  * the signal is received, we call intread to interrupt the iread.
  20  */
  21
  22 #include "less.h"
  23 #include <signal.h>
  24
  25 /*
  26  * "sigs" contains bits indicating signals which need to be processed.
  27  */
  28 public int sigs;
  29
  30 extern int sc_width, sc_height;
  31 extern int screen_trashed;
  32 extern int lnloop;
  33 extern int linenums;
  34 extern int wscroll;
  35 extern int reading;
  36 extern int quit_on_intr;
  37 extern long jump_sline_fraction;
  38
  39 /*
  40  * Interrupt signal handler.
  41  */
  42         /* ARGSUSED*/
  43         static RETSIGTYPE
  44 u_interrupt(type)
  45         int type;
  46 {
  47 #if OS2
  48         LSIGNAL(SIGINT, SIG_ACK);
  49 #endif
  50         LSIGNAL(SIGINT, u_interrupt);
  51         sigs |= S_INTERRUPT;
  52 #if MSDOS_COMPILER==DJGPPC
  53         /*
  54          * If a keyboard has been hit, it must be Ctrl-C
  55          * (as opposed to Ctrl-Break), so consume it.
  56          * (Otherwise, Less will beep when it sees Ctrl-C from keyboard.)
  57          */
  58         if (kbhit())
  59                 getkey();
  60 #endif
  61         if (reading)
  62                 intread();
  63 }
  64
  65 #ifdef SIGTSTP
  66 /*
  67  * "Stop" (^Z) signal handler.
  68  */
  69         /* ARGSUSED*/
  70         static RETSIGTYPE
  71 stop(type)
  72         int type;
  73 {
  74         LSIGNAL(SIGTSTP, stop);
  75         sigs |= S_STOP;
  76         if (reading)
  77                 intread();
  78 }
  79 #endif
  80
  81 #ifdef SIGWINCH
  82 /*
  83  * "Window" change handler
  84  */
  85         /* ARGSUSED*/
  86         public RETSIGTYPE
  87 winch(type)
  88         int type;
  89 {
  90         LSIGNAL(SIGWINCH, winch);
  91         sigs |= S_WINCH;
  92 }
  93 #else
  94 #ifdef SIGWIND
  95 /*
  96  * "Window" change handler
  97  */
  98         /* ARGSUSED*/
  99         public RETSIGTYPE
 100 winch(type)
 101         int type;
 102 {
 103         LSIGNAL(SIGWIND, winch);
 104         sigs |= S_WINCH;
 105         if (reading)
 106                 intread();
 107 }
 108 #endif
 109 #endif
 110
 111 #if MSDOS_COMPILER==WIN32C
 112 /*
 113  * Handle CTRL-C and CTRL-BREAK keys.
 114  */
 115 #include "windows.h"
 116
 117         static BOOL WINAPI
 118 wbreak_handler(dwCtrlType)
 119         DWORD dwCtrlType;
 120 {
 121         switch (dwCtrlType)
 122         {
 123         case CTRL_C_EVENT:
 124         case CTRL_BREAK_EVENT:
 125                 sigs |= S_INTERRUPT;
 126                 return (TRUE);
 127         default:
 128                 break;
 129         }
 130         return (FALSE);
 131 }
 132 #endif
 133
 134 /*
 135  * Set up the signal handlers.
 136  */
 137         public void
 138 init_signals(on)
 139         int on;
 140 {
 141         if (on)
 142         {
 143                 /*
 144                  * Set signal handlers.
 145                  */
 146                 (void) LSIGNAL(SIGINT, u_interrupt);
 147 #if MSDOS_COMPILER==WIN32C
 148                 SetConsoleCtrlHandler(wbreak_handler, TRUE);
 149 #endif
 150 #ifdef SIGTSTP
 151                 (void) LSIGNAL(SIGTSTP, stop);
 152 #endif
 153 #ifdef SIGWINCH
 154                 (void) LSIGNAL(SIGWINCH, winch);
 155 #endif
 156 #ifdef SIGWIND
 157                 (void) LSIGNAL(SIGWIND, winch);
 158 #endif
 159 #ifdef SIGQUIT
 160                 (void) LSIGNAL(SIGQUIT, SIG_IGN);
 161 #endif
 162         } else
 163         {
 164                 /*
 165                  * Restore signals to defaults.
 166                  */
 167                 (void) LSIGNAL(SIGINT, SIG_DFL);
 168 #if MSDOS_COMPILER==WIN32C
 169                 SetConsoleCtrlHandler(wbreak_handler, FALSE);
 170 #endif
 171 #ifdef SIGTSTP
 172                 (void) LSIGNAL(SIGTSTP, SIG_DFL);
 173 #endif
 174 #ifdef SIGWINCH
 175                 (void) LSIGNAL(SIGWINCH, SIG_IGN);
 176 #endif
 177 #ifdef SIGWIND
 178                 (void) LSIGNAL(SIGWIND, SIG_IGN);
 179 #endif
 180 #ifdef SIGQUIT
 181                 (void) LSIGNAL(SIGQUIT, SIG_DFL);
 182 #endif
 183         }
 184 }
 185
 186 /*
 187  * Process any signals we have received.
 188  * A received signal cause a bit to be set in "sigs".
 189  */
 190         public void
 191 psignals()
 192 {
 193         register int tsignals;
 194
 195         if ((tsignals = sigs) == 0)
 196                 return;
 197         sigs = 0;
 198
 199 #ifdef SIGTSTP
 200         if (tsignals & S_STOP)
 201         {
 202                 /*
 203                  * Clean up the terminal.
 204                  */
 205 #ifdef SIGTTOU
 206                 LSIGNAL(SIGTTOU, SIG_IGN);
 207 #endif
 208                 clear_bot();
 209                 deinit();
 210                 flush();
 211                 raw_mode(0);
 212 #ifdef SIGTTOU
 213                 LSIGNAL(SIGTTOU, SIG_DFL);
 214 #endif
 215                 LSIGNAL(SIGTSTP, SIG_DFL);
 216                 kill(getpid(), SIGTSTP);
 217                 /*
 218                  * ... Bye bye. ...
 219                  * Hopefully we'll be back later and resume here...
 220                  * Reset the terminal and arrange to repaint the
 221                  * screen when we get back to the main command loop.
 222                  */
 223                 LSIGNAL(SIGTSTP, stop);
 224                 raw_mode(1);
 225                 init();
 226                 screen_trashed = 1;
 227                 tsignals |= S_WINCH;
 228         }
 229 #endif
 230 #ifdef S_WINCH
 231         if (tsignals & S_WINCH)
 232         {
 233                 int old_width, old_height;
 234                 /*
 235                  * Re-execute scrsize() to read the new window size.
 236                  */
 237                 old_width = sc_width;
 238                 old_height = sc_height;
 239                 get_term();
 240                 if (sc_width != old_width || sc_height != old_height)
 241                 {
 242                         wscroll = (sc_height + 1) / 2;
 243                         calc_jump_sline();
 244                         screen_trashed = 1;
 245                 }
 246         }
 247 #endif
 248         if (tsignals & S_INTERRUPT)
 249         {
 250                 if (quit_on_intr)
 251                         quit(QUIT_OK);
 252                 bell();
 253                 /*
 254                  * {{ You may wish to replace the bell() with
 255                  *    error("Interrupt", NULL_PARG); }}
 256                  */
 257
 258                 /*
 259                  * If we were interrupted while in the "calculating
 260                  * line numbers" loop, turn off line numbers.
 261                  */
 262                 if (lnloop)
 263                 {
 264                         lnloop = 0;
 265                         if (linenums == 2)
 266                                 screen_trashed = 1;
 267                         linenums = 0;
 268                         error("Line numbers turned off", NULL_PARG);
 269                 }
 270
 271         }
 272 }