Add _IO_stdin_used in version-script to fix SIGBUSes on Sparc.
authorWalter Doekes <walter+asterisk@wjd.nu>
Thu, 22 Aug 2013 08:26:55 +0000 (08:26 +0000)
committerWalter Doekes <walter+asterisk@wjd.nu>
Thu, 22 Aug 2013 08:26:55 +0000 (08:26 +0000)
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
........

Merged revisions 397378 from http://svn.asterisk.org/svn/asterisk/branches/11

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@397379 65c4cc65-6c06-0410-ace0-fbb531ad65f3

default.exports
main/asterisk.exports.in

index 5e76754..6d9344d 100644 (file)
@@ -1,4 +1,8 @@
 {
+       global:
+               /* See main/asterisk.exports.in for an explanation why this is
+                * needed. */
+               _IO_stdin_used;
        local:
                *;
 };
index 3f32be1..364b3b0 100644 (file)
                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:
                *;
 };