On Tue, 13 Sep 2011, Daniel Stenberg wrote:
Quite right. I'll follow up with a fix that keeps the state better to avoid
this. Although it seems to be a rather rare case in my tests...
See attachment.
But really, we need to put a more generic concept in place - as Henrik
mentioned before - to prevent that this kind of errors sneak in all over.
I'm gonna give this some further thoughts and come back with some kind of
suggestion.
I think my sftp_read and window adjust patches probably can go in anyway, as
they should at least make the situation better.
--
/ daniel.haxx.se
From 30e28817f2b7d834447ab5cb1ec920c11181a52d Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <dan...@haxx.se>
Date: Tue, 13 Sep 2011 20:16:59 +0200
Subject: [PATCH] sftp_read: use a state variable to avoid bad writes
When a channel_write call has gotten an EAGAIN back, we try harder to
continue the same write in the subsequent invoke.
---
src/sftp.c | 11 +++++++++++
src/sftp.h | 5 +----
2 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/src/sftp.c b/src/sftp.c
index 45e0439..357b87b 100644
--- a/src/sftp.c
+++ b/src/sftp.c
@@ -1107,6 +1107,12 @@ static ssize_t sftp_read(LIBSSH2_SFTP_HANDLE * handle, char *buffer,
filep->data = NULL;
}
+ /* if we previously aborted a channel_write due to EAGAIN, we must
+ continue that writing so that we don't risk trying to send another
+ channel_write here to enlarge the receive window */
+ if(sftp->read_state == libssh2_NB_state_sent)
+ goto send_read_requests;
+
/* We allow a number of bytes being requested at any given time without
having been acked - until we reach EOF. */
if(!filep->eof) {
@@ -1198,6 +1204,8 @@ static ssize_t sftp_read(LIBSSH2_SFTP_HANDLE * handle, char *buffer,
to create more packets */
}
+ send_read_requests:
+
/* move through the READ packets that haven't been sent and send as many
as possible - remember that we don't block */
chunk = _libssh2_list_first(&handle->packet_list);
@@ -1207,11 +1215,14 @@ static ssize_t sftp_read(LIBSSH2_SFTP_HANDLE * handle, char *buffer,
rc = _libssh2_channel_write(channel, 0,
&chunk->packet[chunk->sent],
chunk->lefttosend);
+ sftp->read_state = libssh2_NB_state_idle;
if(rc < 0) {
if(rc != LIBSSH2_ERROR_EAGAIN)
/* error */
return rc;
eagain++;
+ fprintf(stderr, "bing\n");
+ sftp->read_state = libssh2_NB_state_sent;
break;
}
diff --git a/src/sftp.h b/src/sftp.h
index 99636fa..44edc36 100644
--- a/src/sftp.h
+++ b/src/sftp.h
@@ -1,7 +1,7 @@
#ifndef _LIBSSH2_SFP_H
#define _LIBSSH2_SFTP_H
/*
- * Copyright (C) 2010 by Daniel Stenberg
+ * Copyright (C) 2010, 2011 by Daniel Stenberg
* Author: Daniel Stenberg <dan...@haxx.se>
*
* Redistribution and use in source and binary forms,
@@ -160,9 +160,6 @@ struct _LIBSSH2_SFTP
/* State variables used in libssh2_sftp_read() */
libssh2_nonblocking_states read_state;
- unsigned char *read_packet;
- uint32_t read_request_id;
- size_t read_total_read;
/* State variables used in libssh2_sftp_readdir() */
libssh2_nonblocking_states readdir_state;
--
1.7.5.4
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