[stgt] [PATCH] fix check of sent len in mtask_recv_send_handler(), report exceptions in concat_write()

[nezhinsky at gmail.com]

From: Alexander Nezhinsky <alexandern at mellanox.com>

This patch hopefully fixes the problem reported by Brad. Please verify. 

1) mtask->done is reset to 0 when transitioning to MTASK_STATE_PDU_SEND because it is used
 as the offset into concat_buf, while rsp->len accounts for the total response length, incl. the header;
 thus the check if the entire mtask resp is sent should subtract header len.
2) when writing concat_buf to a socket file, if the buffer offset is past the buffer end,
 return -1 and set errno=EINVAL instead of just returning 0.
 The problem is that concat_write() regularly returns the retcode from write(), which is either
 the number of written bytes or -1 (and then errno describes the error). Thus when we avoid
 calling write() the same convention should be simulated.
 Similar fix in case of a previous error, then concat_buf->err stores the relevant errno,
 so -1 is returned and errno is reset to the error code.

Signed-off-by: Alexander Nezhinsky <alexandern at mellanox.com>
---
 usr/concat_buf.c |   12 ++++++++----
 usr/mgmt.c       |    4 ++--
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/usr/concat_buf.c b/usr/concat_buf.c
index 9395f4b..00661d4 100644
--- a/usr/concat_buf.c
+++ b/usr/concat_buf.c
@@ -74,13 +74,17 @@ int concat_write(struct concat_buf *b, int fd, int offset)
 {
 	concat_buf_finish(b);
 
-	if (b->err)
-		return b->err;
+	if (b->err) {
+		errno = b->err;
+		return -1;
+	}
 
 	if (b->size - offset > 0)
 		return write(fd, b->buf + offset, b->size - offset);
-	else
-		return 0;
+	else {
+		errno = EINVAL;
+		return -1;
+	}
 }
 
 void concat_buf_release(struct concat_buf *b)
diff --git a/usr/mgmt.c b/usr/mgmt.c
index 8b62d13..8915dea 100644
--- a/usr/mgmt.c
+++ b/usr/mgmt.c
@@ -590,9 +590,9 @@ static void mtask_recv_send_handler(int fd, int events, void *data)
 		break;
 	case MTASK_STATE_PDU_SEND:
 		err = concat_write(&mtask->rsp_concat, fd, mtask->done);
-		if (err > 0) {
+		if (err >= 0) {
 			mtask->done += err;
-			if (mtask->done == rsp->len) {
+			if (mtask->done == (rsp->len - sizeof(*rsp))) {
 				if (req->mode == MODE_SYSTEM &&
 				    req->op == OP_DELETE &&
 				    !rsp->err)
-- 
1.7.9.6

--
To unsubscribe from this list: send the line "unsubscribe stgt" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html