Eric Blake <ebb9 <at> byu.net> writes:
> This example flushes out the libsigsegv interaction for both cygwin 1.5 and
> today's CVS cygwin 1.7.
Given that I have proven a case where cygwin relies on internal fault handling
for more than just EFAULT, and that correct program behavior is broken if
libsigsegv built without --enable-EFAULT interferes, how about this patch?
From: Eric Blake <e...@byu.net>
Date: Tue, 24 Nov 2009 09:35:41 -0700
Subject: [PATCH] Flip default of --enable-EFAULT.
* configure.ac: Default --enable-EFAULT to on.
* README: Tweak wording accordingly.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 6 ++++++
README | 8 ++++----
configure.ac | 2 +-
3 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 2eb27a6..5892dec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2009-11-24 Eric Blake <e...@byu.net>
+
+ Flip default of --enable-EFAULT.
+ * configure.ac: Default --enable-EFAULT to on.
+ * README: Tweak wording accordingly.
+
2009-11-21 Eric Blake <e...@byu.net>
Bruno Haible <br...@clisp.org>
diff --git a/README b/README
index 86671eb..06db747 100644
--- a/README
+++ b/README
@@ -119,10 +119,10 @@ Installation instructions on Woe32:
Configuration options:
- - If the option --enable-EFAULT is given, libsigsegv will try to arrange
- that passing invalid memory adresses to system calls (such as read(),
- write(), etc.) makes the system call fail with errno = EFAULT, rather than
- invoking the signal handler. POSIX does not specify the behaviour of
+ - If the option --disable-EFAULT is given, libsigsegv will try to intercept
+ invalid memory adresses to system calls (such as read(), write(), etc.)
+ and invoke a handler, even if the system call would otherwise fail with
+ errno = EFAULT with no signal. POSIX does not specify the behaviour of
system calls in this case (see
<http://www.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html>,
under "[EFAULT]" and under "Memory Protection"). Therefore correct
diff --git a/configure.ac b/configure.ac
index 20380b8..3c75949 100644
--- a/configure.ac
+++ b/configure.ac
@@ -946,7 +946,7 @@ AC_ARG_ENABLE([EFAULT],
enable_EFAULT=no
fi
],
- [enable_EFAULT=no])
+ [enable_EFAULT=yes])
AC_MSG_RESULT([$enable_EFAULT])
if test $enable_EFAULT = yes; then
AC_DEFINE([ENABLE_EFAULT], [1],
--
1.6.4.2
