Imported Upstream version 1.4.17

[platform/upstream/m4.git] / lib / c-stack.c

diff --git a/lib/c-stack.c b/lib/c-stack.c
index 7f0f488..03db242 100644 (file)
--- a/lib/c-stack.c
+++ b/lib/c-stack.c
@@ -1,6 +1,6 @@
 /* Stack overflow handling.
 
-   Copyright (C) 2002, 2004, 2006, 2008-2011 Free Software Foundation, Inc.
+   Copyright (C) 2002, 2004, 2006, 2008-2013 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -104,8 +104,7 @@ static char const * volatile stack_overflow_message;
    appears to have been a stack overflow, or with a core dump
    otherwise.  This function is async-signal-safe.  */
 
-static void die (int) __attribute__ ((noreturn));
-static void
+static _Noreturn void
 die (int signo)
 {
   char const *message;
@@ -182,9 +181,7 @@ static int segv_handler (void *address __attribute__ ((unused)),
 /* Handle a segmentation violation that is likely to be a stack
    overflow and exit.  This function is async-signal-safe.  */
 
-static void overflow_handler (int, stackoverflow_context_t)
-  __attribute__ ((noreturn));
-static void
+static _Noreturn void
 overflow_handler (int emergency,
                   stackoverflow_context_t context __attribute__ ((unused)))
 {
@@ -223,29 +220,12 @@ c_stack_action (void (*action) (int))
 
 #elif HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING
 
-/* Direction of the C runtime stack.  This function is
-   async-signal-safe.  */
-
-# if STACK_DIRECTION
-#  define find_stack_direction(ptr) STACK_DIRECTION
-# else
-#  if ! SIGINFO_WORKS || HAVE_XSI_STACK_OVERFLOW_HEURISTIC
-static int
-find_stack_direction (char const *addr)
-{
-  char dummy;
-  return ! addr ? find_stack_direction (&dummy) : addr < &dummy ? 1 : -1;
-}
-#  endif
-# endif
-
 # if SIGINFO_WORKS
 
 /* Handle a segmentation violation and exit.  This function is
    async-signal-safe.  */
 
-static void segv_handler (int, siginfo_t *, void *) __attribute__((noreturn));
-static void
+static _Noreturn void
 segv_handler (int signo, siginfo_t *info,
               void *context __attribute__ ((unused)))
 {
@@ -257,7 +237,7 @@ segv_handler (int signo, siginfo_t *info,
 
      Note that although both Linux and Solaris provide
      sigaltstack, SA_ONSTACK, and SA_SIGINFO, currently only
-     Solaris satisfies the XSI heueristic.  This is because
+     Solaris satisfies the XSI heuristic.  This is because
      Solaris populates uc_stack with the details of the
      interrupted stack, while Linux populates it with the details
      of the current stack.  */
@@ -266,17 +246,14 @@ segv_handler (int signo, siginfo_t *info,
   if (0 < info->si_code)
     {
       /* If the faulting address is within the stack, or within one
-         page of the stack end, assume that it is a stack
-         overflow.  */
+         page of the stack, assume that it is a stack overflow.  */
       ucontext_t const *user_context = context;
       char const *stack_base = user_context->uc_stack.ss_sp;
       size_t stack_size = user_context->uc_stack.ss_size;
       char const *faulting_address = info->si_addr;
-      size_t s = faulting_address - stack_base;
       size_t page_size = sysconf (_SC_PAGESIZE);
-      if (find_stack_direction (NULL) < 0)
-        s += page_size;
-      if (s < stack_size + page_size)
+      size_t s = faulting_address - stack_base + page_size;
+      if (s < stack_size + 2 * page_size)
         signo = 0;
 
 #   if DEBUG