From: Walter Doekes <walter+asterisk@wjd.nu>
Date: Thu, 22 Aug 2013 08:22:39 +0000 (+0000)
Subject: Add _IO_stdin_used in version-script to fix SIGBUSes on Sparc.
X-Git-Tag: 11.6.0-rc1~3^2~46
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0bdd6ce7068b90e060823ac663892cc9bd25f0e3;p=thirdparty%2Fasterisk.git

Add _IO_stdin_used in version-script to fix SIGBUSes on Sparc.

The --version-script,asterisk.exports linker flag (and the module
exports) didn't provide _IO_stdin_used in the list of exported symbols.
That causes some kind of libc compatibility mode to kick in, where
stdio file structures (stdout/stderr) land somewhere else. In the
case of the Sparc, they landed on misaligned memory.

This became apparent first after r376428 (Reorder startup sequence)
when a lot of ast_log's were replaced with fprintf's. Writing to
stderr triggered a SIGBUS. (Compared to x86 and amd64 architectures,
the Sparc is very picky about memory alignment.)

(issue ASTERISK-21763)
(issue ASTERISK-21665)

Reported by: Jeremy Kister
Review: https://reviewboard.asterisk.org/r/2760/
........

Merged revisions 397377 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@397378 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---

diff --git a/default.exports b/default.exports
index 5e767549c4..6d9344d3b5 100644
--- a/default.exports
+++ b/default.exports
@@ -1,4 +1,8 @@
 {
+	global:
+		/* See main/asterisk.exports.in for an explanation why this is
+		 * needed. */
+		_IO_stdin_used;
 	local:
 		*;
 };
diff --git a/main/asterisk.exports.in b/main/asterisk.exports.in
index 49d3a44a4e..e521d10770 100644
--- a/main/asterisk.exports.in
+++ b/main/asterisk.exports.in
@@ -46,6 +46,25 @@
 		LINKER_SYMBOL_PREFIXres_srtp;
 		LINKER_SYMBOL_PREFIXres_srtp_policy;
 		LINKER_SYMBOL_PREFIXsecure_call_info;
+		/*
+
+		If _IO_stdin_used is not exported, stdout/stderr may not get
+		properly aligned. That causes breakage on some architectures.
+
+		http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=634261#51
+		http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=634261#94
+		http://lists.gnu.org/archive/html/bug-glibc/2001-12/msg00203.html
+
+		We export the symbol to get proper behaviour. Now printf
+		doesn't SIGBUS anymore on the SPARC.
+
+		Michael Karcher wrote on Jan 13, 2013:
+		> A build process that mangles the export of _IO_stdin_used is
+		> (as defined by the libc ABI, even if not explicitly written
+		> down) broken. [...]
+
+		*/
+		LINKER_SYMBOL_PREFIX_IO_stdin_used;
 	local:
 		*;
 };