Treat SIGBUS like SIFSEGV on platforms that need it.

[gnulib.git] / m4 / c-stack.m4

diff --git a/m4/c-stack.m4 b/m4/c-stack.m4
index 5069333..efd6798 100644 (file)
--- a/m4/c-stack.m4
+++ b/m4/c-stack.m4
@@ -7,14 +7,33 @@
 
 # Written by Paul Eggert.
 
-# serial 7
+# serial 8
 
 AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
   [# for STACK_DIRECTION
    AC_REQUIRE([AC_FUNC_ALLOCA])
+   AC_REQUIRE([AC_CANONICAL_HOST])
    AC_CHECK_FUNCS_ONCE([setrlimit])
    AC_CHECK_HEADERS_ONCE([ucontext.h])
 
+   dnl List of signals that are sent when an invalid virtual memory address
+   dnl is accessed, or when the stack overflows.
+   dnl Either { SIGSEGV } or { SIGSEGV, SIGBUS }.
+   case "$host_os" in
+     sunos4* | freebsd* | dragonfly* | openbsd* | netbsd* | kfreebsd* | knetbsd*) # BSD systems
+       FAULT_YIELDS_SIGBUS=1 ;;
+     hpux*) # HP-UX
+       FAULT_YIELDS_SIGBUS=1 ;;
+     macos* | darwin*) # MacOS X
+       FAULT_YIELDS_SIGBUS=1 ;;
+     gnu*) # Hurd
+       FAULT_YIELDS_SIGBUS=1 ;;
+     *)
+       FAULT_YIELDS_SIGBUS=0 ;;
+   esac
+   AC_DEFINE_UNQUOTED([FAULT_YIELDS_SIGBUS], [$FAULT_YIELDS_SIGBUS],
+     [Define to 1 if an invalid memory address access may yield a SIGBUS.])
+
    AC_CACHE_CHECK([for working C stack overflow detection],
      [ac_cv_sys_stack_overflow_works],
      [AC_TRY_RUN(
@@ -62,6 +81,10 @@ AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
           sigemptyset (&act.sa_mask);
           act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
           act.sa_handler = segv_handler;
+          #if FAULT_YIELDS_SIGBUS
+          if (sigaction (SIGBUS, &act, 0) < 0)
+            return -1;
+          #endif
           return sigaction (SIGSEGV, &act, 0);
         }
         static volatile int *
@@ -244,6 +267,10 @@ int main ()
           sigemptyset (&act.sa_mask);
           act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
           act.sa_sigaction = segv_handler;
+          #if FAULT_YIELDS_SIGBUS
+          if (sigaction (SIGBUS, &act, 0) < 0)
+            return -1;
+          #endif
           return sigaction (SIGSEGV, &act, 0);
         }
         static volatile int *