[gentoo-commits] proj/sandbox:master commit in: /

["Mike Frysinger" <vapier@gentoo.org>]

commit:     4fcb367b1a7ff06a55c8bc4a25c38e46b77a1261
Author:     Mike Frysinger <vapier <AT> gentoo <DOT> org>
AuthorDate: Sat Jun 23 02:42:08 2012 +0000
Commit:     Mike Frysinger <vapier <AT> gentoo <DOT> org>
CommitDate: Sat Jun 23 23:07:27 2012 +0000
URL:        http://git.overlays.gentoo.org/gitweb/?p=proj/sandbox.git;a=commit;h=4fcb367b

libsandbox: handle broken kernel headers

Sometimes the struct in asm/ptrace.h is too small for what the kernel
actually writes.  Check to see which struct is larger (the one that the
kernel declares or the C library declares), and use that.

Signed-off-by: Mike Frysinger <vapier <AT> gentoo.org>

---
 configure.ac |    2 ++
 localdecls.h |   11 +++++++++++
 2 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/configure.ac b/configure.ac
index da6f75d..573e412 100644
--- a/configure.ac
+++ b/configure.ac
@@ -119,6 +119,8 @@ AC_CHECK_TYPES([sighandler_t, sig_t, __sighandler_t],,,[#include <signal.h>])
 save_CPPFLAGS=$CPPFLAGS
 CPPFLAGS="-I$srcdir $CPPFLAGS"
 AC_CHECK_TYPES([struct user_regs_struct, struct pt_regs],,,[#include "headers.h"])
+AC_CHECK_SIZEOF([struct user_regs_struct],,[#include "headers.h"])
+AC_CHECK_SIZEOF([struct pt_regs],,[#include "headers.h"])
 CPPFLAGS=$save_CPPFLAGS
 
 dnl Checks for library functions.

diff --git a/localdecls.h b/localdecls.h
index eef7295..be99617 100644
--- a/localdecls.h
+++ b/localdecls.h
@@ -68,6 +68,17 @@ typedef __sighandler_t sighandler_t;
 #endif
 
 #define HAVE_TRACE_REGS
+#if defined(HAVE_STRUCT_PT_REGS) && defined(HAVE_STRUCT_USER_REGS_STRUCT)
+/*
+ * Some systems have broken kernel headers who declare struct pt_regs as
+ * smaller than what the kernel actually operates on.  If we have both
+ * reg structs available, pick the one that is larger in the hopes that
+ * we won't randomly clobber memory.
+ */
+# if SIZEOF_STRUCT_PT_REGS < SIZEOF_STRUCT_USER_REGS_STRUCT
+#  undef HAVE_STRUCT_PT_REGS
+# endif
+#endif
 #if defined(HAVE_STRUCT_PT_REGS)
 typedef struct pt_regs trace_regs;
 #elif defined(HAVE_STRUCT_USER_REGS_STRUCT)