Backport due to incorrect socket syscall definitions on s390x with Linux 4.3 headers.

[Stefan Liebler <stli at linux dot vnet dot ibm dot com>]

Hi,

Beginning with Linux 4.3, the kernel headers contain direct system call 
numbers __NR_socket etc. on s390x. On older kernels, the 
socket-multiplexer syscall __NR_socketcall was used.

To enable these new syscalls, the patch
"S390: Call direct system calls for socket operations."
(https://sourceware.org/git/?p=glibc.git;a=commit;h=016495b818cb61df7d0d10e6db54074271b3e3a5)
was applied upstream.
If glibc 2.23 is configured with --enable-kernel=4.3 and newer,
the direct socket syscalls are used.
For older kernels, the socket-multiplexer syscall is used.

In glibc 2.22 and earlier, this patch is currently not applied.
If you build glibc on an kernel < 4.3, the socket-multiplexer syscall is 
used. But if you build glibc on kernel >= 4.3, the direct
socket-syscalls are used. If you install this glibc on an
kernel < 4.3, all socket operations will fail.
See "Bug 19682 - s390x: Incorrect syscall definitions cause breakage 
with Linux 4.3 headers" 
(https://sourceware.org/bugzilla/show_bug.cgi?id=19682)
The configure switch --enable-kernel does not influence this behaviour 
on older glibc-releases.

The solution is to remove the direct socket-syscalls in 
sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list (see attached patch) 
on older glibc-releases as it was done by the upstream patch, too. These 
entries were never used on s390x, but the c-files in 
sysdeps/unix/sysv/linux/.
After this removal, the behaviour of the socket functions are not 
changed compared to the original glibc release version and the 
socket-multiplexer-syscall is always used.

Florian Weimer told me, that he already did this for Fedora 23 (glibc 
2.22) and Fedora 22 (glibc 2.21).
Thus, backporting this to glibc branch 2.22, and 2.21 would be the best 
for Fedora.

Which other glibc-branches should be updated???

Please give feedback.

Bye
Stefan

---
ChangeLog:

	* sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list:
	Remove socketcall syscalls.

diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list b/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
index 5b8c102..9f03d26 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/syscalls.list
@@ -12,22 +12,3 @@ shmget		-	shmget		i:iii	__shmget	shmget
 semop		-	semop		i:ipi	__semop		semop
 semget		-	semget		i:iii	__semget	semget
 semctl		-	semctl		i:iiii	__semctl	semctl
-
-# proper socket implementations:
-accept		-	accept		Ci:iBN	__libc_accept	__accept accept
-bind		-	bind		i:ipi	__bind		bind
-connect		-	connect		Ci:ipi	__libc_connect	__connect connect
-getpeername	-	getpeername	i:ipp	__getpeername	getpeername
-getsockname	-	getsockname	i:ipp	__getsockname	getsockname
-getsockopt	-	getsockopt	i:iiiBN	__getsockopt	getsockopt
-listen		-	listen		i:ii	__listen	listen
-recv		-	recv		Ci:ibni	__libc_recv	__recv recv
-recvfrom	-	recvfrom	Ci:ibniBN	__libc_recvfrom	__recvfrom recvfrom
-recvmsg		-	recvmsg		Ci:ipi	__libc_recvmsg	__recvmsg recvmsg
-send		-	send		Ci:ibni	__libc_send	__send send
-sendmsg		-	sendmsg		Ci:ipi	__libc_sendmsg	__sendmsg sendmsg
-sendto		-	sendto		Ci:ibnibn	__libc_sendto	__sendto sendto
-setsockopt	-	setsockopt	i:iiibn	__setsockopt	setsockopt
-shutdown	-	shutdown	i:ii	__shutdown	shutdown
-socket		-	socket		i:iii	__socket	socket
-socketpair	-	socketpair	i:iiif	__socketpair	socketpair