Update.

1998-06-11  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/generic/getenv.c: Fix last change.

1998-06-10  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/generic/backtrace.c: Provide generic implementation.

1998-06-10  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* configure.in: Give visual feedback of the default directories we
	added.

1998-06-11  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* io/fts.c (fts_build): Define oflag only if needed.

1998-06-11  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/libm-ieee754/w_exp10.c: Add missing close comment.

3 files changed, 57 insertions, 6 deletions

diff --git a/sysdeps/generic/backtrace.c b/sysdeps/generic/backtrace.c
index 26bf9d4..7ac1d5f 100644
--- a/sysdeps/generic/backtrace.c
+++ b/sysdeps/generic/backtrace.c
@@ -1,4 +1,4 @@
-/* Return backtrace of current program state.
+/* Return backtrace of current program state.  Generic version.
    Copyright (C) 1998 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
@@ -21,14 +21,63 @@
 #include <execinfo.h>
 
 
+/* This is a global variable set at program start time.  It marks the
+   highest used stack address.  */
+extern void *__libc_stack_end;
+
+
+/* This implementation assumes a stack layout that matches the defaults
+   used by gcc's `__builtin_frame_address' and `__builtin_return_address'
+   (FP is the frame pointer register):
+
+	  +-----------------+     +-----------------+
+    FP -> | previous FP --------> | previous FP ------>...
+	  |                 |     |                 |
+	  | return address  |     | return address  |
+	  +-----------------+     +-----------------+
+
+  */
+
+/* Get some notion of the current stack.  Need not be exactly the top
+   of the stack, just something somewhere in the current frame.  */
+#ifndef CURRENT_STACK_FRAME
+# define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
+#endif
+
+struct layout
+{
+  struct layout *next;
+  void *return_address;
+};
+
 int
 __backtrace (array, size)
      void **array;
      int size;
 {
-  /* We don't generally have the possibility to determine the stack
-     trace.  Even gcc's `__builtin_return_address' feature cannot help
-     since it requires a constant argument.  */
-  return 0;
+  struct layout *current;
+  void *top_frame;
+  void *top_stack;
+  int cnt = 0;
+
+  top_frame = __builtin_frame_address (0);
+  top_stack = CURRENT_STACK_FRAME;
+
+  /* We skip the call to this function, it makes no sense to record it.  */
+  current = (struct layout *) top_frame;
+  while (cnt < size)
+    {
+      if ((void *) current < top_stack || (void *) current > __libc_stack_end)
+       /* This means the address is out of range.  Note that for the
+	  toplevel we see a frame pointer with value NULL which clearly is
+	  out of range.  */
+	break;
+
+      array[cnt++] = current->return_address;
+
+      current = current->next;
+    }
+
+  return cnt;
 }
 weak_alias (__backtrace, backtrace)
diff --git a/sysdeps/generic/getenv.c b/sysdeps/generic/getenv.c
index b6f405d..584b120 100644
--- a/sysdeps/generic/getenv.c
+++ b/sysdeps/generic/getenv.c
@@ -37,7 +37,7 @@ char *
 getenv (name)
      const char *name;
 {
-  const size_t len = strlen (name);
+  size_t len = strlen (name);
   char **ep;
   uint16_t name_start;
 
diff --git a/sysdeps/libm-ieee754/w_exp10.c b/sysdeps/libm-ieee754/w_exp10.c
index cb27159..bf0d361 100644
--- a/sysdeps/libm-ieee754/w_exp10.c
+++ b/sysdeps/libm-ieee754/w_exp10.c
@@ -1,5 +1,7 @@
 /* @(#)w_exp10.c
  * Conversion to exp10 by Ulrich Drepper <drepper@cygnus.com>.
+ */
+
 /*
  * ====================================================
  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.