X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fc-stack.c;h=1dddeefc412d1242c03839bebb583b1fbfc6dcf3;hb=26c5fd742f9136e2ddbd4695a9172c3fa30ea260;hp=c46c23136111701b7f77cb9609bfeded145475be;hpb=065a39d1ff7eb9dba34f3a4020be752a53546a43;p=gnulib.git

diff --git a/lib/c-stack.c b/lib/c-stack.c
index c46c23136..1dddeefc4 100644
--- a/lib/c-stack.c
+++ b/lib/c-stack.c
@@ -1,6 +1,7 @@
 /* Stack overflow handling.
 
-   Copyright (C) 2002, 2004, 2006, 2008 Free Software Foundation, Inc.
+   Copyright (C) 2002, 2004, 2006, 2008, 2009 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
@@ -45,9 +46,6 @@
 #define _(msgid) gettext (msgid)
 
 #include <errno.h>
-#ifndef ENOTSUP
-# define ENOTSUP EINVAL
-#endif
 
 #include <signal.h>
 #if ! HAVE_STACK_T && ! defined stack_t
@@ -67,9 +65,6 @@ typedef struct sigaltstack stack_t;
 #endif
 
 #include <unistd.h>
-#ifndef STDERR_FILENO
-# define STDERR_FILENO 2
-#endif
 
 #if HAVE_LIBSIGSEGV
 # include <sigsegv.h>
@@ -82,6 +77,9 @@ typedef struct sigaltstack stack_t;
 # define SIGACTION_WORKS 1
 #else
 # define SIGACTION_WORKS 0
+# ifndef SA_ONSTACK
+#  define SA_ONSTACK 0
+# endif
 #endif
 
 extern char *program_name;
@@ -117,7 +115,8 @@ die (int signo)
   abort ();
 }
 
-#if (HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK) || HAVE_LIBSIGSEGV
+#if (HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK \
+     && HAVE_STACK_OVERFLOW_HANDLING) || HAVE_LIBSIGSEGV
 
 /* Storage for the alternate signal stack.  */
 static union
@@ -210,7 +209,7 @@ c_stack_action (void (*action) (int))
   return 0;
 }
 
-#elif HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK
+#elif HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING
 
 /* Direction of the C runtime stack.  This function is
    async-signal-safe.  */
@@ -237,21 +236,21 @@ segv_handler (int signo, siginfo_t *info,
 	      void *context __attribute__ ((unused)))
 {
   /* Clear SIGNO if it seems to have been a stack overflow.  */
-  if (0 < info->si_code)
-    {
 #  if ! HAVE_XSI_STACK_OVERFLOW_HEURISTIC
-      /* We can't easily determine whether it is a stack overflow; so
-	 assume that the rest of our program is perfect (!) and that
-	 this segmentation violation is a stack overflow.
-
-	 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 populates uc_stack with the details of the
-	 interrupted stack, while Linux populates it with the details
-	 of the current stack.  */
-      signo = 0;
+  /* We can't easily determine whether it is a stack overflow; so
+     assume that the rest of our program is perfect (!) and that
+     this segmentation violation is a stack overflow.
+
+     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 populates uc_stack with the details of the
+     interrupted stack, while Linux populates it with the details
+     of the current stack.  */
+  signo = 0;
 #  else
+  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.  */
@@ -276,8 +275,8 @@ segv_handler (int signo, siginfo_t *info,
 	write (STDERR_FILENO, buf, strlen (buf));
       }
 #   endif
-#  endif
     }
+#  endif
 
   die (signo);
 }
@@ -290,8 +289,15 @@ c_stack_action (void (*action) (int))
   stack_t st;
   struct sigaction act;
   st.ss_flags = 0;
+# if SIGALTSTACK_SS_REVERSED
+  /* Irix mistakenly treats ss_sp as the upper bound, rather than
+     lower bound, of the alternate stack.  */
+  st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ - sizeof (void *);
+  st.ss_size = sizeof alternate_signal_stack.buffer - sizeof (void *);
+# else
   st.ss_sp = alternate_signal_stack.buffer;
   st.ss_size = sizeof alternate_signal_stack.buffer;
+# endif
   r = sigaltstack (&st, NULL);
   if (r != 0)
     return r;
@@ -309,14 +315,19 @@ c_stack_action (void (*action) (int))
   act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
   act.sa_sigaction = segv_handler;
 # else
-  act.sa_flags = SA_NODEFER | SA_RESETHAND;
+  act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
   act.sa_handler = die;
 # endif
 
+# if FAULT_YIELDS_SIGBUS
+  if (sigaction (SIGBUS, &act, NULL) < 0)
+    return -1;
+# endif
   return sigaction (SIGSEGV, &act, NULL);
 }
 
-#else /* ! ((HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK) || HAVE_LIBSIGSEGV) */
+#else /* ! ((HAVE_SIGALTSTACK && HAVE_DECL_SIGALTSTACK
+	     && HAVE_STACK_OVERFLOW_HANDLING) || HAVE_LIBSIGSEGV) */
 
 int
 c_stack_action (void (*action) (int)  __attribute__ ((unused)))