Subject: [ libssh2-Bugs-2785173 ] channel_read returns LIBSSH2_ERROR_EAGAIN, no data on socket

[ libssh2-Bugs-2785173 ] channel_read returns LIBSSH2_ERROR_EAGAIN, no data on socket

From: SourceForge.net <noreply_at_sourceforge.net>
Date: Fri, 01 May 2009 18:19:24 +0000

Bugs item #2785173, was opened at 2009-05-01 19:42
Message generated for change (Comment added) made by bagder
You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=703942&aid=2785173&group_id=125852

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Category: API
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Nobody/Anonymous (nobody)
>Assigned to: Daniel Stenberg (bagder)
Summary: channel_read returns LIBSSH2_ERROR_EAGAIN, no data on socket

Initial Comment:
While using libssh2_channel_read_ex(), I found that when the last of the data has been read, the libssh2_channel_read_ex() may return LIBSSH2_ERROR_EAGAIN, but a poll() on the socket times out (eventually). I diagnosed this as packets (channel eof and channel close) in memory, but not processed, so libssh2_channel_eof() remains false. Root caused as a "single shot" call to _libssh2_transport_read() in channel_read(). No call to _libssh2_transport_read() should be made unless the caller continues to call the function until it returns a non-positive value (0 or negative). This will prevent it from leaving unprocessed buffers in memory.

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>Comment By: Daniel Stenberg (bagder)
Date: 2009-05-01 20:19

Message:
This explanation is not clear to me. If the reason for the
LIBSSH2_ERROR_EAGAIN is a "single shot" call to _libssh2_transport_read()
in channel_read() then didn't that transport function return EAGAIN? If so,
what good would adding a loop do?

Or perhaps put in another way: can you please provide a patch showing what
you suggest?

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You can respond by visiting:
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Received on 2009-05-01