usr.bin/doscmd/signal.c

   1 /*
   2  * Copyright (c) 1992, 1993, 1996
   3  *      Berkeley Software Design, Inc.  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, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Berkeley Software
  16  *      Design, Inc.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28  * SUCH DAMAGE.
  29  *
  30  *      BSDI signal.c,v 2.2 1996/04/08 19:33:06 bostic Exp
  31  *
  32  * $FreeBSD: src/usr.bin/doscmd/signal.c,v 1.6.2.1 2002/04/25 11:04:51 tg Exp $
  33  * $DragonFly: src/usr.bin/doscmd/signal.c,v 1.4 2004/01/22 03:22:53 rob Exp $
  34  */
  35
  36 #include "doscmd.h"
  37 #include "trap.h"
  38
  39 static void     (*handler[NSIG])(struct sigframe *);
  40 static char     signal_stack[16 * 1024];
  41 #define PSS(w) { char s; printf(w " @ %08x\n", (signal_stack + sizeof signal_stack) - &s); }
  42
  43 struct sigframe *saved_sigframe;
  44 regcontext_t *saved_regcontext;
  45 int             saved_valid = 0;
  46
  47 static void
  48 sanity_check(struct sigframe *sf __unused)
  49 {
  50 #if 0
  51     static sigset_t oset;
  52     int i;
  53
  54     for (i = 1; i < 32; ++i) {
  55         if (sigismember(&sf->sf_sc.sc_mask, i) != sigismember(&oset, i))
  56             fprintf(debugf, "Signal %s %s being blocked\n",
  57                     sys_signame[i],
  58                     sigismember(&sf->sf_sc.sc_mask, i) ? "now" : "no longer");
  59     }
  60     oset = sf->sf_sc.sc_mask;
  61 #endif
  62
  63     if (dead)
  64         fatal("attempting to return to vm86 while dead");
  65 }
  66
  67 #if defined(__DragonFly__) || defined(USE_VM86)
  68 static void
  69 generichandler(struct sigframe sf)
  70 {
  71     if (sf.sf_uc.uc_mcontext.mc_eflags & PSL_VM) {
  72         saved_sigframe = &sf;
  73         saved_regcontext = (regcontext_t *)&(sf.sf_uc.uc_mcontext);
  74         saved_valid = 1;
  75         if (handler[sf.sf_signum])
  76             (*handler[sf.sf_signum])(&sf);
  77         saved_valid = 0;
  78         sanity_check(&sf);
  79     } else {
  80         if (handler[sf.sf_signum])
  81             (*handler[sf.sf_signum])(&sf);
  82     }
  83 }
  84 #else
  85 #error BSD/OS sigframe/trapframe kernel interface not currently supported.
  86 #endif
  87
  88 void setsignal(int s, void (*h)(struct sigframe *))
  89 {
  90     static int first = 1;
  91     struct sigaction sa;
  92
  93     if (first) {
  94         struct sigaltstack sstack;
  95
  96         sstack.ss_sp = signal_stack;
  97         sstack.ss_size = sizeof signal_stack;
  98         sstack.ss_flags = 0;
  99         sigaltstack (&sstack, NULL);
 100         first = 0;
 101     }
 102
 103     if (s >= 0 && s < NSIG) {
 104         handler[s] = h;
 105
 106         sa.sa_handler = (__sighandler_t *)generichandler;
 107         sigemptyset(&sa.sa_mask);
 108         sigaddset(&sa.sa_mask, SIGIO);
 109         sigaddset(&sa.sa_mask, SIGALRM);
 110         sa.sa_flags = SA_ONSTACK;
 111         sigaction(s, &sa, NULL);
 112     }
 113 }