Re: Bug#953728: gambc: FTBFS on s390x

[Nick Gasson <nick@nickg.me.uk>]

On 05/23/20 13:13 PM, Adrian Bunk wrote:
> On Thu, Mar 12, 2020 at 04:36:17PM +0000, Ivo De Decker wrote:
>> package: src:gambc
>> version: 4.9.3-1
>> severity: serious
>> tags: ftbfs
>> 
>> Hi,
>> 
>> The latest upload of gambc to unstable fails on s390x:
>> 
>> https://buildd.debian.org/status/package.php?p=gambc
>
> Can an s390x porter please have a look?
>

I had a look at this because it's blocking another package, slib. I can
reproduce the hanging test case in qemu-user. It's testing timeouts with
UDP sockets but there seems to be a bug in the set_socket_blocking_mode
function where it passes an unsigned long argument to the FIONBIO ioctl
which actually takes an int parameter.

  unsigned long param = !blocking;

  return SOCKET_CALL_ERROR(IOCTL_SOCKET(s, FIONBIO, &param));

The parameter value is only ever 0 or 1 so it's benign on little-endian
LP64 systems but on a big-endian system the parameter is always 0 when
read as an int so the socket is never put in non-blocking mode and reads
from it hang.

The patch below fixes the problem from me on S390 qemu-user. I'm
wondering if someone with access to real hardware can verify?

diff --git a/lib/os_io.c b/lib/os_io.c
index 046be4a6bd30..b8b5f96c191e 100644
--- a/lib/os_io.c
+++ b/lib/os_io.c
@@ -5458,7 +5458,7 @@ ___BOOL blocking;)
 
 #ifdef FIONBIO
 
-  unsigned long param = !blocking;
+  int param = !blocking;
 
   return SOCKET_CALL_ERROR(IOCTL_SOCKET(s, FIONBIO, &param));


--
Thanks,
Nick