From a8e02b591b0c82c1f75f4f51bc683d9775f13d54 Mon Sep 17 00:00:00 2001
From: Volker Lendecke <vl@samba.org>
Date: Sat, 23 May 2009 16:10:54 +0200
Subject: [PATCH] Add "err_on_readability" to writev_send

A socket where the other side has closed only becomes readable. To catch
errors early when sitting in a pure writev, we need to also test for
readability.
---
 lib/async_req/async_sock.c        | 15 +++++++++++++--
 lib/async_req/async_sock.h        |  1 +
 source3/lib/wb_reqtrans.c         |  4 ++--
 source3/libsmb/async_smb.c        |  4 ++--
 source3/rpc_server/srv_pipe_hnd.c |  2 +-
 5 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/lib/async_req/async_sock.c b/lib/async_req/async_sock.c
index a3a6d75f3a0..d7f31768ef8 100644
--- a/lib/async_req/async_sock.c
+++ b/lib/async_req/async_sock.c
@@ -327,6 +327,7 @@ struct writev_state {
 	struct iovec *iov;
 	int count;
 	size_t total_size;
+	uint16_t flags;
 };
 
 static void writev_trigger(struct tevent_req *req, void *private_data);
@@ -335,6 +336,7 @@ static void writev_handler(struct tevent_context *ev, struct tevent_fd *fde,
 
 struct tevent_req *writev_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 			       struct tevent_queue *queue, int fd,
+			       bool err_on_readability,
 			       struct iovec *iov, int count)
 {
 	struct tevent_req *req;
@@ -353,11 +355,15 @@ struct tevent_req *writev_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 	if (state->iov == NULL) {
 		goto fail;
 	}
+	state->flags = TEVENT_FD_WRITE;
+	if (err_on_readability) {
+		state->flags |= TEVENT_FD_READ;
+	}
 
 	if (queue == NULL) {
 		struct tevent_fd *fde;
 		fde = tevent_add_fd(state->ev, state, state->fd,
-				    TEVENT_FD_WRITE, writev_handler, req);
+				    state->flags, writev_handler, req);
 		if (tevent_req_nomem(fde, req)) {
 			return tevent_req_post(req, ev);
 		}
@@ -378,7 +384,7 @@ static void writev_trigger(struct tevent_req *req, void *private_data)
 	struct writev_state *state = tevent_req_data(req, struct writev_state);
 	struct tevent_fd *fde;
 
-	fde = tevent_add_fd(state->ev, state, state->fd, TEVENT_FD_WRITE,
+	fde = tevent_add_fd(state->ev, state, state->fd, state->flags,
 			    writev_handler, req);
 	if (fde == NULL) {
 		tevent_req_error(req, ENOMEM);
@@ -397,6 +403,11 @@ static void writev_handler(struct tevent_context *ev, struct tevent_fd *fde,
 
 	to_write = 0;
 
+	if (flags & TEVENT_FD_READ) {
+		tevent_req_error(req, EPIPE);
+		return;
+	}
+
 	for (i=0; i<state->count; i++) {
 		to_write += state->iov[i].iov_len;
 	}
diff --git a/lib/async_req/async_sock.h b/lib/async_req/async_sock.h
index ec859dc0aee..a50e93238aa 100644
--- a/lib/async_req/async_sock.h
+++ b/lib/async_req/async_sock.h
@@ -41,6 +41,7 @@ int async_connect_recv(struct tevent_req *req, int *perrno);
 
 struct tevent_req *writev_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 			       struct tevent_queue *queue, int fd,
+			       bool err_on_readability,
 			       struct iovec *iov, int count);
 ssize_t writev_recv(struct tevent_req *req, int *perrno);
 
diff --git a/source3/lib/wb_reqtrans.c b/source3/lib/wb_reqtrans.c
index df92ecf8b06..3fdf62a1087 100644
--- a/source3/lib/wb_reqtrans.c
+++ b/source3/lib/wb_reqtrans.c
@@ -152,7 +152,7 @@ struct tevent_req *wb_req_write_send(TALLOC_CTX *mem_ctx,
 		count = 2;
 	}
 
-	subreq = writev_send(state, ev, queue, fd, state->iov, count);
+	subreq = writev_send(state, ev, queue, fd, true, state->iov, count);
 	if (tevent_req_nomem(subreq, req)) {
 		return tevent_req_post(req, ev);
 	}
@@ -309,7 +309,7 @@ struct tevent_req *wb_resp_write_send(TALLOC_CTX *mem_ctx,
 		count = 2;
 	}
 
-	subreq = writev_send(state, ev, queue, fd, state->iov, count);
+	subreq = writev_send(state, ev, queue, fd, true, state->iov, count);
 	if (tevent_req_nomem(subreq, req)) {
 		return tevent_req_post(req, ev);
 	}
diff --git a/source3/libsmb/async_smb.c b/source3/libsmb/async_smb.c
index 12bc0a6fb31..6edfe514b80 100644
--- a/source3/libsmb/async_smb.c
+++ b/source3/libsmb/async_smb.c
@@ -680,10 +680,10 @@ static NTSTATUS cli_smb_req_iov_send(struct tevent_req *req,
 		iov[0].iov_base = (void *)buf;
 		iov[0].iov_len = talloc_get_size(buf);
 		subreq = writev_send(state, state->ev, state->cli->outgoing,
-				     state->cli->fd, iov, 1);
+				     state->cli->fd, false, iov, 1);
 	} else {
 		subreq = writev_send(state, state->ev, state->cli->outgoing,
-				     state->cli->fd, iov, iov_count);
+				     state->cli->fd, false, iov, iov_count);
 	}
 	if (subreq == NULL) {
 		return NT_STATUS_NO_MEMORY;
diff --git a/source3/rpc_server/srv_pipe_hnd.c b/source3/rpc_server/srv_pipe_hnd.c
index f2441619ac0..a17adfb7a03 100644
--- a/source3/rpc_server/srv_pipe_hnd.c
+++ b/source3/rpc_server/srv_pipe_hnd.c
@@ -1221,7 +1221,7 @@ struct tevent_req *np_write_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
 		state->iov.iov_len = len;
 
 		subreq = writev_send(state, ev, p->write_queue, p->fd,
-				     &state->iov, 1);
+				     false, &state->iov, 1);
 		if (subreq == NULL) {
 			goto fail;
 		}
-- 
2.34.1