netbsd.h (ENABLE_EXECUTE_STACK): Remove.
2011-05-29 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
Joseph Myers <joseph@codesourcery.com>
gcc:
* config/alpha/netbsd.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/alpha/osf5.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/darwin.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/i386/mingw32.h (MINGW_ENABLE_EXECUTE_STACK): Remove.
(ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
[IN_LIBGCC2]: Don't include <windows.h>.
* config/i386/netbsd-elf.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/i386/netbsd64.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/netbsd.h (NETBSD_ENABLE_EXECUTE_STACK): Remove.
* config/openbsd.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/sol2.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/sparc/freebsd.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/sparc/netbsd-elf.h (ENABLE_EXECUTE_STACK): Remove.
(HAVE_ENABLE_EXECUTE_STACK): Define.
* config/alpha/alpha.c (alpha_trampoline_init): Test
HAVE_ENABLE_EXECUTE_STACK.
* config/i386/i386.c (ix86_trampoline_init): Likewise.
* config/sparc/sparc.c (sparc32_initialize_trampoline): Likewise.
(sparc64_initialize_trampoline): Likewise.
* libgcc2.c [L_enable_execute_stack]: Remove.
* system.h (ENABLE_EXECUTE_STACK): Poison.
* doc/tm.texi.in (Trampolines, ENABLE_EXECUTE_STACK): Remove.
* doc/tm.texi: Regenerate.
* Makefile.in (LIBGCC2_CFLAGS): Add -fbuilding-libgcc.
gcc/c-family:
* c.opt (fbuilding-libgcc): New option.
* c-cppbuiltin.c (c_cpp_builtins): Define
__LIBGCC_TRAMPOLINE_SIZE__ if flag_building_libgcc.
libgcc:
* enable-execute-stack-empty.c: New file.
* enable-execute-stack-mprotect.c: New file.
* config/i386/enable-execute-stack-mingw32.c: New file.
* config.host (enable_execute_stack): New variable.
Select appropriate variants.
* configure.ac: Link enable-execute-stack.c to
$enable_execute_stack.
* configure: Regenerate.
* Makefile.in (LIB2ADD): Add enable-execute-stack.c.
(lib2funcs): Remove _enable_execute_stack.
Co-Authored-By: Joseph Myers <joseph@codesourcery.com>
From-SVN: r174843
diff --git a/libgcc/enable-execute-stack-mprotect.c b/libgcc/enable-execute-stack-mprotect.c
new file mode 100644
index 0000000..1ad77bd
--- /dev/null
+++ b/libgcc/enable-execute-stack-mprotect.c
@@ -0,0 +1,119 @@
+/* Implement __enable_execute_stack using mprotect(2).
+ Copyright (C) 2011 Free Software Foundation, Inc.
+
+ This file is part of GCC.
+
+ GCC is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 3, or (at your option) any later
+ version.
+
+ GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sys/mman.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#define STACK_PROT_RWX (PROT_READ | PROT_WRITE | PROT_EXEC)
+
+static int need_enable_exec_stack;
+
+static void check_enabling (void) __attribute__ ((unused));
+extern void __enable_execute_stack (void *);
+
+#if defined __FreeBSD__
+#include <sys/sysctl.h>
+
+static void __attribute__ ((constructor))
+check_enabling (void)
+{
+ int prot = 0;
+ size_t len = sizeof (prot);
+
+ sysctlbyname ("kern.stackprot", &prot, &len, NULL, 0);
+ if (prot != STACK_PROT_RWX)
+ need_enable_exec_stack = 1;
+}
+#elif defined __sun__ && defined __svr4__
+static void __attribute__ ((constructor))
+check_enabling (void)
+{
+ int prot = (int) sysconf (_SC_STACK_PROT);
+
+ if (prot != STACK_PROT_RWX)
+ need_enable_exec_stack = 1;
+}
+#else
+/* There is no way to query the execute permission of the stack, so
+ we always issue the mprotect() call. */
+
+static int need_enable_exec_stack = 1;
+#endif
+
+#if defined __NetBSD__
+/* Note that we go out of our way to use namespace-non-invasive calls
+ here. Unfortunately, there is no libc-internal name for mprotect(). */
+
+#include <sys/sysctl.h>
+
+extern int __sysctl (int *, unsigned int, void *, size_t *, void *, size_t);
+
+static int
+getpagesize (void)
+{
+ static int size;
+
+ if (size == 0)
+ {
+ int mib[2];
+ size_t len;
+
+ mib[0] = CTL_HW;
+ mib[1] = HW_PAGESIZE;
+ len = sizeof (size);
+ (void) __sysctl (mib, 2, &size, &len, NULL, 0);
+ }
+ return size;
+}
+#endif /* __NetBSD__ */
+
+/* Attempt to turn on access permissions for the stack. Unfortunately it
+ is not possible to make this namespace-clean.*/
+
+void
+__enable_execute_stack (void *addr)
+{
+ if (!need_enable_exec_stack)
+ return;
+ else
+ {
+ static long size, mask;
+
+ if (size == 0) {
+ size = getpagesize ();
+ mask = ~(size - 1);
+ }
+
+ char *page = (char *) (((long) addr) & mask);
+ char *end = (char *)
+ ((((long) (addr + __LIBGCC_TRAMPOLINE_SIZE__)) & mask) + size);
+
+ if (mprotect (page, end - page, STACK_PROT_RWX) < 0)
+ /* Note that no errors should be emitted by this code; it is
+ considered dangerous for library calls to send messages to
+ stdout/stderr. */
+ abort ();
+ }
+}