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[dropping bug-gnulib, adding m4-patches]
According to Bruno Haible on 12/6/2008 8:45 AM:
> Eric Blake wrote:
>> maybe swapping the order will help, where I install the
>> SIGBUS handler first, and then c_stack_action can optionally install an
>> alternate handler on platforms where it is needed for stack overflow?
>
> Yes, I was going to propose this too.
I'm installing this on the stackovf branch (which I still need to merge
into both branch-1.6 and master). I'm also debating whether to release m4
1.4.13 (it depends on how long it takes me to get m4 1.6 in nice shape);
but if I do end up releasing 1.4.13, this patch is on the list for
inclusion on branch-1.4.
- --
Don't work too hard, make some time for fun as well!
Eric Blake [EMAIL PROTECTED]
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>From f66f95f60436fe3c8e805268338fbfb1087a385d Mon Sep 17 00:00:00 2001
From: Eric Blake <[EMAIL PROTECTED]>
Date: Sat, 6 Dec 2008 10:53:22 -0700
Subject: [PATCH] Don't override signal handlers installed by c-stack.
* src/m4.c (main): Reorder installation of signal handlers, so we
don't trash a SIGBUS handler installed by c-stack. Also provide a
SIGSEGV fallback, for platforms where c-stack combined with
libsigsegv uses something lower level than SIGSEGV.
Signed-off-by: Eric Blake <[EMAIL PROTECTED]>
---
ChangeLog | 8 ++++++++
src/m4.c | 10 +++++++---
2 files changed, 15 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index f13b710..0dab381 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
2008-12-06 Eric Blake <[EMAIL PROTECTED]>
+ Don't override signal handlers installed by c-stack.
+ * src/m4.c (main): Reorder installation of signal handlers, so we
+ don't trash a SIGBUS handler installed by c-stack. Also provide a
+ SIGSEGV fallback, for platforms where c-stack combined with
+ libsigsegv uses something lower level than SIGSEGV.
+
+2008-12-06 Eric Blake <[EMAIL PROTECTED]>
+
Upgrade to FDL 1.3, keep COPYING in repository.
* Makefile.am (MAINTAINERCLEANFILES): Don't remove COPYING.
* .cvsignore: Don't ignore it.
diff --git a/src/m4.c b/src/m4.c
index a24f82d..6031797 100644
--- a/src/m4.c
+++ b/src/m4.c
@@ -466,9 +466,10 @@ main (int argc, char *const *argv, char *const *envp)
/* Stack overflow and program error handling. Ignore failure to
install a handler, since this is merely for improved output on
- crash, and we should never crash ;). */
- if (c_stack_action (fault_handler) == 0)
- nesting_limit = 0;
+ crash, and we should never crash ;). We install SIGBUS and
+ SIGSEGV handlers prior to using the c-stack module; depending on
+ the platform, c-stack will then override none, SIGSEGV, or both
+ handlers. */
program_error_message
= xasprintf (_("internal error detected; please report this bug to <%s>"),
PACKAGE_BUGREPORT);
@@ -483,10 +484,13 @@ main (int argc, char *const *argv, char *const *envp)
to default signal behavior. */
act.sa_flags = SA_NODEFER | SA_RESETHAND;
act.sa_handler = fault_handler;
+ sigaction (SIGSEGV, &act, NULL);
sigaction (SIGABRT, &act, NULL);
sigaction (SIGILL, &act, NULL);
sigaction (SIGFPE, &act, NULL);
sigaction (SIGBUS, &act, NULL);
+ if (c_stack_action (fault_handler) == 0)
+ nesting_limit = 0;
#ifdef DEBUG_STKOVF
/* Make it easier to test our fault handlers. Exporting M4_CRASH=0
--
1.6.0.4
