[RFC PATCH v2 0/2] vsock: handle writes to shutdowned socket

[Arseniy Krasnov]

Hello,

this small patchset adds POSIX compliant behaviour on writes to the
socket which was shutdowned with 'shutdown()' (both sides - local with
SHUT_WR flag, peer - with SHUT_RD flag). According POSIX we must send
SIGPIPE in such cases (but SIGPIPE is not send when MSG_NOSIGNAL is set).

First patch is implemented in the same way as net/ipv4/tcp.c:tcp_sendmsg_locked().
It uses 'sk_stream_error()' function which handles EPIPE error. Another
way is to use code from net/unix/af_unix.c:unix_stream_sendmsg() where
same logic from 'sk_stream_error()' is implemented "from scratch", but
it doesn't check 'sk_err' field. I think error from this field has more
priority to be returned from syscall. So I guess it is better to reuse
currently implemented 'sk_stream_error()' function.

Test is also added.

Head for this patchset is:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=b38460bc463c54e0c15ff3b37e81f7e2059bb9bb

Link to v1:
https://lore.kernel.org/netdev/20230801141727.481156-1-AVKrasnov@xxxxxxxxxxxxxx/

Changelog:
v1 -> v2:
 * 0001 stills the same - SIGPIPE is sent only for SOCK_STREAM as discussed in v1
   with Stefano Garzarella <sgarzare@xxxxxxxxxx>.
 * 0002 - use 'sig_atomic_t' instead of 'bool' for flag variables updated from
   signal handler.

Arseniy Krasnov (2):
  vsock: send SIGPIPE on write to shutdowned socket
  test/vsock: shutdowned socket test

 net/vmw_vsock/af_vsock.c         |   3 +
 tools/testing/vsock/vsock_test.c | 138 +++++++++++++++++++++++++++++++
 2 files changed, 141 insertions(+)

-- 
2.25.1