Annotation of src/usr.bin/less/signal.c, Revision 1.1
1.1 ! etheisen 1: /*
! 2: * Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman
! 3: * All rights reserved.
! 4: *
! 5: * Redistribution and use in source and binary forms, with or without
! 6: * modification, are permitted provided that the following conditions
! 7: * are met:
! 8: * 1. Redistributions of source code must retain the above copyright
! 9: * notice, this list of conditions and the following disclaimer.
! 10: * 2. Redistributions in binary form must reproduce the above copyright
! 11: * notice in the documentation and/or other materials provided with
! 12: * the distribution.
! 13: *
! 14: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
! 15: * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 16: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
! 17: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
! 18: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
! 19: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
! 20: * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
! 21: * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
! 22: * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
! 23: * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
! 24: * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
! 25: */
! 26:
! 27:
! 28: /*
! 29: * Routines dealing with signals.
! 30: *
! 31: * A signal usually merely causes a bit to be set in the "signals" word.
! 32: * At some convenient time, the mainline code checks to see if any
! 33: * signals need processing by calling psignal().
! 34: * If we happen to be reading from a file [in iread()] at the time
! 35: * the signal is received, we call intread to interrupt the iread.
! 36: */
! 37:
! 38: #include "less.h"
! 39: #include <signal.h>
! 40:
! 41: /*
! 42: * "sigs" contains bits indicating signals which need to be processed.
! 43: */
! 44: public int sigs;
! 45:
! 46: extern int sc_width, sc_height;
! 47: extern int screen_trashed;
! 48: extern int lnloop;
! 49: extern int linenums;
! 50: extern int wscroll;
! 51: extern int reading;
! 52:
! 53: /*
! 54: * Interrupt signal handler.
! 55: */
! 56: /* ARGSUSED*/
! 57: static RETSIGTYPE
! 58: u_interrupt(type)
! 59: int type;
! 60: {
! 61: #if OS2
! 62: SIGNAL(SIGINT, SIG_ACK);
! 63: #endif
! 64: SIGNAL(SIGINT, u_interrupt);
! 65: sigs |= S_INTERRUPT;
! 66: if (reading)
! 67: intread();
! 68: }
! 69:
! 70: #ifdef SIGTSTP
! 71: /*
! 72: * "Stop" (^Z) signal handler.
! 73: */
! 74: /* ARGSUSED*/
! 75: static RETSIGTYPE
! 76: stop(type)
! 77: int type;
! 78: {
! 79: SIGNAL(SIGTSTP, stop);
! 80: sigs |= S_STOP;
! 81: if (reading)
! 82: intread();
! 83: }
! 84: #endif
! 85:
! 86: #ifdef SIGWINCH
! 87: /*
! 88: * "Window" change handler
! 89: */
! 90: /* ARGSUSED*/
! 91: public RETSIGTYPE
! 92: winch(type)
! 93: int type;
! 94: {
! 95: SIGNAL(SIGWINCH, winch);
! 96: sigs |= S_WINCH;
! 97: if (reading)
! 98: intread();
! 99: }
! 100: #else
! 101: #ifdef SIGWIND
! 102: /*
! 103: * "Window" change handler
! 104: */
! 105: /* ARGSUSED*/
! 106: public RETSIGTYPE
! 107: winch(type)
! 108: int type;
! 109: {
! 110: SIGNAL(SIGWIND, winch);
! 111: sigs |= S_WINCH;
! 112: if (reading)
! 113: intread();
! 114: }
! 115: #endif
! 116: #endif
! 117:
! 118: /*
! 119: * Set up the signal handlers.
! 120: */
! 121: public void
! 122: init_signals(on)
! 123: int on;
! 124: {
! 125: if (on)
! 126: {
! 127: /*
! 128: * Set signal handlers.
! 129: */
! 130: (void) SIGNAL(SIGINT, u_interrupt);
! 131: #ifdef SIGTSTP
! 132: (void) SIGNAL(SIGTSTP, stop);
! 133: #endif
! 134: #ifdef SIGWINCH
! 135: (void) SIGNAL(SIGWINCH, winch);
! 136: #else
! 137: #ifdef SIGWIND
! 138: (void) SIGNAL(SIGWIND, winch);
! 139: #endif
! 140: #endif
! 141: } else
! 142: {
! 143: /*
! 144: * Restore signals to defaults.
! 145: */
! 146: (void) SIGNAL(SIGINT, SIG_DFL);
! 147: #ifdef SIGTSTP
! 148: (void) SIGNAL(SIGTSTP, SIG_DFL);
! 149: #endif
! 150: #ifdef SIGWINCH
! 151: (void) SIGNAL(SIGWINCH, SIG_IGN);
! 152: #endif
! 153: #ifdef SIGWIND
! 154: (void) SIGNAL(SIGWIND, SIG_IGN);
! 155: #endif
! 156: }
! 157: }
! 158:
! 159: /*
! 160: * Process any signals we have received.
! 161: * A received signal cause a bit to be set in "sigs".
! 162: */
! 163: public void
! 164: psignals()
! 165: {
! 166: register int tsignals;
! 167:
! 168: if ((tsignals = sigs) == 0)
! 169: return;
! 170: sigs = 0;
! 171:
! 172: #ifdef SIGTSTP
! 173: if (tsignals & S_STOP)
! 174: {
! 175: /*
! 176: * Clean up the terminal.
! 177: */
! 178: #ifdef SIGTTOU
! 179: SIGNAL(SIGTTOU, SIG_IGN);
! 180: #endif
! 181: clear_bot();
! 182: deinit();
! 183: flush();
! 184: raw_mode(0);
! 185: #ifdef SIGTTOU
! 186: SIGNAL(SIGTTOU, SIG_DFL);
! 187: #endif
! 188: SIGNAL(SIGTSTP, SIG_DFL);
! 189: kill(getpid(), SIGTSTP);
! 190: /*
! 191: * ... Bye bye. ...
! 192: * Hopefully we'll be back later and resume here...
! 193: * Reset the terminal and arrange to repaint the
! 194: * screen when we get back to the main command loop.
! 195: */
! 196: SIGNAL(SIGTSTP, stop);
! 197: raw_mode(1);
! 198: init();
! 199: screen_trashed = 1;
! 200: tsignals |= S_WINCH;
! 201: }
! 202: #endif
! 203: #ifdef S_WINCH
! 204: if (tsignals & S_WINCH)
! 205: {
! 206: int old_width, old_height;
! 207: /*
! 208: * Re-execute scrsize() to read the new window size.
! 209: */
! 210: old_width = sc_width;
! 211: old_height = sc_height;
! 212: get_term();
! 213: if (sc_width != old_width || sc_height != old_height)
! 214: {
! 215: wscroll = (sc_height + 1) / 2;
! 216: screen_trashed = 1;
! 217: }
! 218: }
! 219: #endif
! 220: if (tsignals & S_INTERRUPT)
! 221: {
! 222: bell();
! 223: /*
! 224: * {{ You may wish to replace the bell() with
! 225: * error("Interrupt", NULL_PARG); }}
! 226: */
! 227:
! 228: /*
! 229: * If we were interrupted while in the "calculating
! 230: * line numbers" loop, turn off line numbers.
! 231: */
! 232: if (lnloop)
! 233: {
! 234: lnloop = 0;
! 235: if (linenums == 2)
! 236: screen_trashed = 1;
! 237: linenums = 0;
! 238: error("Line numbers turned off", NULL_PARG);
! 239: }
! 240:
! 241: }
! 242: }
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