Bruno Haible <bruno <at> clisp.org> writes:
> > Here's the minimal patch needed to CVS libsigsegv to expose the bug, as
> > well as work around it for Irix 5.3.
>
> Nice work! I'm applying this only slightly modified version.
> - In the configuration test, keep room to both sides of the ss_sp value.
> On IRIX, we don't want the test to crash. We want it to exit(1)
reasonably.
We need to do this consistently, then. The subsequent configure check (whether
longjmp works from a stack overflow handler) is needlessly falling foul of the
Irix sigaltstack bug.
2008-09-23 Eric Blake <[EMAIL PROTECTED]>
Use 2 * SIGSTKSZ consistently in m4 checks.
* m4/sigaltstack.m4 (SV_SIGALTSTACK): Work around Irix sigaltstack
bug.
* m4/sigaltstack-longjmp.m4 (SV_TRY_LEAVE_HANDLER_LONGJMP):
Likewise.
* m4/sigaltstack-siglongjmp.m4 (SV_TRY_LEAVE_HANDLER_SIGLONGJMP):
Likewise.
Index: m4/sigaltstack-longjmp.m4
===================================================================
RCS file: /sources/libsigsegv/libsigsegv/m4/sigaltstack-longjmp.m4,v
retrieving revision 1.7
diff -u -p -r1.7 sigaltstack-longjmp.m4
--- m4/sigaltstack-longjmp.m4 24 Aug 2008 20:55:16 -0000 1.7
+++ m4/sigaltstack-longjmp.m4 23 Sep 2008 14:13:21 -0000
@@ -1,4 +1,4 @@
-# sigaltstack-longjmp.m4 serial 5 (libsigsegv-2.6)
+# sigaltstack-longjmp.m4 serial 6 (libsigsegv-2.6)
dnl Copyright (C) 2002-2003, 2006, 2008 Bruno Haible <[EMAIL PROTECTED]>
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License. As a special exception to the GNU General
@@ -53,7 +53,7 @@ int recurse (volatile int n)
}
int main ()
{
- char mystack[SIGSTKSZ];
+ char mystack[2 * SIGSTKSZ];
stack_t altstack;
struct sigaction action;
sigset_t emptyset;
@@ -65,9 +65,10 @@ int main ()
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
setrlimit (RLIMIT_STACK, &rl);
#endif
- /* Install the alternate stack. */
- altstack.ss_sp = mystack;
- altstack.ss_size = sizeof (mystack);
+ /* Install the alternate stack. Use midpoint to work around Irix
+ sigaltstack bug. */
+ altstack.ss_sp = mystack + SIGSTKSZ;
+ altstack.ss_size = SIGSTKSZ;
altstack.ss_flags = 0; /* no SS_DISABLE */
if (sigaltstack (&altstack, NULL) < 0)
exit (1);
Index: m4/sigaltstack-siglongjmp.m4
===================================================================
RCS file: /sources/libsigsegv/libsigsegv/m4/sigaltstack-siglongjmp.m4,v
retrieving revision 1.7
diff -u -p -r1.7 sigaltstack-siglongjmp.m4
--- m4/sigaltstack-siglongjmp.m4 24 Aug 2008 20:55:16 -0000 1.7
+++ m4/sigaltstack-siglongjmp.m4 23 Sep 2008 14:13:21 -0000
@@ -1,4 +1,4 @@
-# sigaltstack-siglongjmp.m4 serial 5 (libsigsegv-2.6)
+# sigaltstack-siglongjmp.m4 serial 6 (libsigsegv-2.6)
dnl Copyright (C) 2002-2003, 2006, 2008 Bruno Haible <[EMAIL PROTECTED]>
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License. As a special exception to the GNU General
@@ -51,7 +51,7 @@ int recurse (volatile int n)
}
int main ()
{
- char mystack[SIGSTKSZ];
+ char mystack[2 * SIGSTKSZ];
stack_t altstack;
struct sigaction action;
#ifdef __BEOS__
@@ -66,9 +66,10 @@ int main ()
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
setrlimit (RLIMIT_STACK, &rl);
#endif
- /* Install the alternate stack. */
- altstack.ss_sp = mystack;
- altstack.ss_size = sizeof (mystack);
+ /* Install the alternate stack. Use midpoint to work around Irix
+ sigaltstack bug. */
+ altstack.ss_sp = mystack + SIGSTKSZ;
+ altstack.ss_size = SIGSTKSZ;
altstack.ss_flags = 0; /* no SS_DISABLE */
if (sigaltstack (&altstack, NULL) < 0)
exit (1);
Index: m4/sigaltstack.m4
===================================================================
RCS file: /sources/libsigsegv/libsigsegv/m4/sigaltstack.m4,v
retrieving revision 1.12
diff -u -p -r1.12 sigaltstack.m4
--- m4/sigaltstack.m4 21 Sep 2008 13:41:28 -0000 1.12
+++ m4/sigaltstack.m4 23 Sep 2008 14:13:21 -0000
@@ -1,4 +1,4 @@
-# sigaltstack.m4 serial 9 (libsigsegv-2.7)
+# sigaltstack.m4 serial 10 (libsigsegv-2.7)
dnl Copyright (C) 2002-2006, 2008 Bruno Haible <[EMAIL PROTECTED]>
dnl Copyright (C) 2008 Eric Blake <[EMAIL PROTECTED]>
dnl This file is free software, distributed under the terms of the GNU
@@ -74,7 +74,7 @@ int recurse (volatile int n)
}
int main ()
{
- char mystack[SIGSTKSZ];
+ char mystack[2 * SIGSTKSZ];
stack_t altstack;
struct sigaction action;
#if defined HAVE_SETRLIMIT && defined RLIMIT_STACK
@@ -85,9 +85,10 @@ int main ()
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
setrlimit (RLIMIT_STACK, &rl);
#endif
- /* Install the alternate stack. */
- altstack.ss_sp = mystack;
- altstack.ss_size = sizeof (mystack);
+ /* Install the alternate stack. Use midpoint to work around Irix
+ sigaltstack bug. */
+ altstack.ss_sp = mystack + SIGSTKSZ;
+ altstack.ss_size = SIGSTKSZ;
altstack.ss_flags = 0; /* no SS_DISABLE */
if (sigaltstack (&altstack, NULL) < 0)
exit (1);
