2002-01-07 Michael Snyder <msnyder@redhat.com>

	* infptrace.c (GDB_MAX_ALLOCA): New define.
	(child_xfer_memory): Use xmalloc/xfree instead of alloca if the
	size of the buffer exceeds GDB_MAX_ALLOCA (default 1 megabyte,
	can be overridden with whatever value is appropriate to the host).
	* infttrace.c (child_xfer_memory): Add FIXME warning about use of
	alloca to allocate potentially large buffer.
	* rs6000-nat.c (child_xfer_memory): Ditto.
	* symm-nat.c (child_xfer_memory): Ditto.
	* x86-64-linux-nat.c (child_xfer_memory): Ditto.

diff --git a/gdb/rs6000-nat.c b/gdb/rs6000-nat.c
index 12229cd..94daaff 100644 (file)
--- a/gdb/rs6000-nat.c
+++ b/gdb/rs6000-nat.c
@@ -407,6 +407,9 @@ child_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
     / sizeof (int);
 
   /* Allocate word transfer buffer. */
+  /* FIXME (alloca): This code, cloned from infptrace.c, is unsafe
+     because it uses alloca to allocate a buffer of arbitrary size.
+     For very large xfers, this could crash GDB's stack.  */
   int *buf = (int *) alloca (count * sizeof (int));
 
   int arch64 = ARCH64 ();