Return requested size for malloc_usable_size when MALLOC_CHECK_ > 0

[BZ #1349]

malloc_usable_size returns the usable size in an allocated chunk,
which may be >= the requested size. In the case of MALLOC_CHECK_ being
exported to > 0 however, only the requested size is usable, since a
magic value is written at the end of the request size to trap writes
beyond request bounds. Hence, when MALLOC_CHECK_ is exported to > 0,
malloc_usable_size() should return the request size.

1 files changed, 10 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 069765dcdf..b35fed42d5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2012-09-05  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	[BZ #1349]
+	* malloc/Makefile (tests): Add tst-malloc-usable test case.
+	(tst-malloc-usable-ENV): Set environment for test case.
+	* malloc/hooks.c (malloc_check_get_size): New function to get
+	requested size.
+	* malloc/malloc.c (musable): Use malloc_check_get_size.
+	* malloc/tst-malloc-usable.c: New test case.
+
 2012-09-05  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* stdlib/tst-strtod-overflow.c (TIMEOUT): Define.