--- gforth/engine/signals.c	1999/02/28 08:37:45	1.1
+++ gforth/engine/signals.c	2002/12/24 23:40:30	1.19
@@ -1,6 +1,6 @@
 /* signal handling
 
-  Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
+  Copyright (C) 1995,1996,1997,1998,2000 Free Software Foundation, Inc.
 
   This file is part of Gforth.
 
@@ -16,23 +16,22 @@
 
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
-  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 
 */
 
 
-#define _GNU_SOURCE
-
+#include "config.h"
+#include "forth.h"
 #include <stdio.h>
-#include <signal.h>
 #include <setjmp.h>
 #include <string.h>
 #include <stdlib.h>
 #if !defined(apollo) && !defined(MSDOS)
 #include <sys/ioctl.h>
 #endif
-#include "config.h"
-#include "forth.h"
+/* #include <asm/signal.h> */
+#include <signal.h>
 #include "io.h"
 
 
@@ -46,6 +45,42 @@
 UCell cols=DEFAULTCOLS;
 UCell rows=DEFAULTROWS;
 
+#ifndef SA_NODEFER
+#define SA_NODEFER 0
+/* systems that don't have SA_NODEFER hopefully don't block anyway */
+#endif
+
+#ifndef SA_ONSTACK
+#define SA_ONSTACK 0
+#endif
+
+#ifdef SA_SIGINFO
+void install_signal_handler(int sig, void (*handler)(int, siginfo_t *, void *))
+     /* installs three-argument signal handler for sig */
+{
+  struct sigaction action;
+
+  action.sa_sigaction=handler;
+  sigemptyset(&action.sa_mask);
+  action.sa_flags=SA_RESTART|SA_NODEFER|SA_SIGINFO|SA_ONSTACK; /* pass siginfo */
+  sigaction(sig, &action, NULL);
+}
+#endif
+
+typedef void Sigfunc(int);
+
+Sigfunc *bsd_signal(int signo, Sigfunc *func)
+{
+  struct sigaction act, oact;
+
+  act.sa_handler=func;
+  sigemptyset(&act.sa_mask);
+  act.sa_flags=SA_NODEFER; /* SA_ONSTACK does not work for graceful_exit */
+  if (sigaction(signo,&act,&oact) < 0)
+    return SIG_ERR;
+  else
+    return oact.sa_handler;
+}
 
 static void
 graceful_exit (int sig)
@@ -61,30 +96,84 @@ static void
 signal_throw(int sig)
 {
   int code;
-  struct {
-    int signal;
-    int throwcode;
-  } *p, throwtable[] = {
-    { SIGINT, -28 },
-    { SIGFPE, -55 },
+
+  switch (sig) {
+  case SIGINT: code=-28; break;
+  case SIGFPE: code=-55; break;
 #ifdef SIGBUS
-    { SIGBUS, -23 },
+  case SIGBUS: code=-23; break;
 #endif
-    { SIGSEGV, -9 },
-  };
-  signal(sig,signal_throw);
-  for (code=-256-sig, p=throwtable; p<throwtable+(sizeof(throwtable)/sizeof(*p)); p++)
-    if (sig == p->signal) {
-      code = p->throwcode;
-      break;
-    }
-  longjmp(throw_jmp_buf,code); /* or use siglongjmp ? */
+  case SIGSEGV: code=-9; break;
+  default: code=-256-sig; break;
+  }
+  longjmp(throw_jmp_buf,code); /* !! or use siglongjmp ? */
 }
 
+#ifdef SA_SIGINFO
+static void fpe_handler(int sig, siginfo_t *info, void *_)
+     /* handler for SIGFPE */
+{
+  int code;
+
+  switch(info->si_code) {
+#ifdef FPE_INTDIV
+  case FPE_INTDIV: code=-10; break; /* integer divide by zero */
+#endif
+#ifdef FPE_INTOVF
+  case FPE_INTOVF: code=-11; break; /* integer overflow */
+#endif
+  case FPE_FLTDIV: code=-42; break; /* floating point divide by zero */
+  case FPE_FLTOVF: code=-43; break; /* floating point overflow  */
+  case FPE_FLTUND: code=-54; break; /* floating point underflow  */
+  case FPE_FLTRES: code=-41; break; /* floating point inexact result  */
+#if 0 /* defined by Unix95, but unnecessary */
+  case FPE_FLTINV: /* invalid floating point operation  */
+  case FPE_FLTSUB: /* subscript out of range  */
+#endif
+  default: code=-55; break;
+  }
+  longjmp(throw_jmp_buf,code);
+}
+
+
+#define SPILLAGE 128
+/* if there's a SIGSEGV within SPILLAGE bytes of some stack, we assume
+   that this stack has over/underflowed */
+
+#define JUSTUNDER(addr1,addr2) (((UCell)((addr2)-1-(addr1)))<SPILLAGE)
+/* true is addr1 is just under addr2 */
+
+#define JUSTOVER(addr1,addr2) (((UCell)((addr1)-(addr2)))<SPILLAGE)
+
+#define NEXTPAGE(addr) ((Address)((((UCell)(addr)-1)&-pagesize)+pagesize))
+
+static void segv_handler(int sig, siginfo_t *info, void *_)
+{
+  int code=-9;
+  Address addr=info->si_addr;
+  ImageHeader *h=gforth_header;
+
+  if (JUSTUNDER(addr, h->data_stack_base))
+    code=-3;
+  else if (JUSTOVER(addr, NEXTPAGE(h->data_stack_base+h->data_stack_size)))
+    code=-4;
+  else if (JUSTUNDER(addr, h->return_stack_base))
+    code=-5;
+  else if (JUSTOVER(addr, NEXTPAGE(h->return_stack_base+h->return_stack_size)))
+    code=-6;
+  else if (JUSTUNDER(addr, h->fp_stack_base))
+    code=-44;
+  else if (JUSTOVER(addr, NEXTPAGE(h->fp_stack_base+h->fp_stack_size)))
+    code=-45;
+  longjmp(throw_jmp_buf,code);
+}
+
+#endif /* defined(SA_SIGINFO) */
+
 #ifdef SIGCONT
-static void termprep (int sig)
+static void termprep(int sig)
 {
-  signal(sig,termprep);
+  bsd_signal(sig,termprep);
   terminal_prepped=0;
 }
 #endif
@@ -93,6 +182,7 @@ void get_winsize()
 {
 #ifdef TIOCGWINSZ
   struct winsize size;
+  size.ws_row = size.ws_col = 0;
   
   if (ioctl (1, TIOCGWINSZ, (char *) &size) >= 0) {
     rows = size.ws_row;
@@ -102,28 +192,28 @@ void get_winsize()
   char *s;
   if ((s=getenv("LINES"))) {
     rows=atoi(s);
-    if (rows==0)
-      rows=DEFAULTROWS;
   }
   if ((s=getenv("COLUMNS"))) {
     rows=atoi(s);
-    if (rows==0)
-      cols=DEFAULTCOLS;
   }
 #endif
+  if (rows==0)
+    rows=DEFAULTROWS;
+  if (rows==0)
+    cols=DEFAULTCOLS;
 }
 
 #ifdef SIGWINCH
 static void change_winsize(int sig)
 {
-  signal(sig,change_winsize);
+  /* signal(sig,change_winsize); should not be necessary with bsd_signal */
 #ifdef TIOCGWINSZ
   get_winsize();
 #endif
 }
 #endif
 
-void install_signal_handlers (void)
+void install_signal_handlers(void)
 {
 
 #if 0
@@ -256,12 +346,12 @@ void install_signal_handlers (void)
 #endif
   };
   static short sigs_to_quit [] = {
-#ifdef SIGHUP
-    SIGHUP,
-#endif
 #ifdef SIGQUIT
     SIGQUIT,
 #endif
+#ifdef SIGHUP
+    SIGHUP,
+#endif
 #ifdef SIGABRT
     SIGABRT,
 #endif
@@ -273,6 +363,19 @@ void install_signal_handlers (void)
 #endif
   };
   int i;
+  void (*throw_handler)() = die_on_signal ? graceful_exit : signal_throw;
+#ifdef SIGSTKSZ 
+  stack_t sigstack;
+  int sas_retval=-1;
+
+  sigstack.ss_size=SIGSTKSZ;
+  if ((sigstack.ss_sp = my_alloc(sigstack.ss_size)) != NULL) {
+    sigstack.ss_flags=0;
+    sas_retval=sigaltstack(&sigstack,(stack_t *)0);
+  }
+  if (debug)
+    fprintf(stderr,"sigaltstack: %s\n",strerror(sas_retval));
+#endif
 
 #define DIM(X)		(sizeof (X) / sizeof *(X))
 /*
@@ -280,13 +383,19 @@ void install_signal_handlers (void)
     signal (sigs_to_ignore [i], SIG_IGN);
 */
   for (i = 0; i < DIM (sigs_to_throw); i++)
-    signal (sigs_to_throw [i], die_on_signal ? graceful_exit : signal_throw);
+    bsd_signal(sigs_to_throw[i], throw_handler);
   for (i = 0; i < DIM (sigs_to_quit); i++)
-    signal (sigs_to_quit [i], graceful_exit);
+    bsd_signal(sigs_to_quit [i], graceful_exit);
+#ifdef SA_SIGINFO
+  if (!die_on_signal) {
+    install_signal_handler(SIGFPE, fpe_handler);
+    install_signal_handler(SIGSEGV, segv_handler);
+  }
+#endif
 #ifdef SIGCONT
-    signal (SIGCONT, termprep);
+    bsd_signal(SIGCONT, termprep);
 #endif
 #ifdef SIGWINCH
-    signal (SIGWINCH, change_winsize);
+    bsd_signal(SIGWINCH, change_winsize);
 #endif
 }