Bugs item #2141548, was opened at 2008-10-02 04:11 Message generated for change (Settings changed) made by bagder You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=703942&aid=2141548&group_id=125852
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None >Status: Closed >Resolution: Wont Fix Priority: 3 Private: No Submitted By: Nobody/Anonymous (nobody) Assigned to: Daniel Stenberg (bagder) Summary: libssh2_poll detects data on channel, but no data available Initial Comment: I've got a small home-brewed SSH client and I've encountered a problem in the library with libssh2_poll() when checking for data on a channel. Simply put, here's the setup. I have a thread that polls for data on a channel every few usec. When the libssh2_poll function detects data available to be read on the channel I'm interested in, I immediately try to read from that channel. Trouble is, if its a small piece of data that I'm expecting, the read fails while subsequent polls still think that there is data there. So In my SSH client with a pty, I do something like hit the "z" key. This should send a single character over the lines to the remote SSH server plus any SSH/TCP/IP.... overhead. Now the remote SSH server will echo back the key plus any additional terminal formatting. As soon as I hit my "z" key, libssh2_poll alerts me that data is available to be read from the channel, but attempting to read from the channel doesn't read any data...polling keeps saying theres data, I read nothing... repeat a lot of times... If I keep hitting keystrokes, eventually the channel read picks up the data. So it seems like libssh2 holds onto small packets for some reason. ---------------------------------------------------------------------- Comment By: Daniel Stenberg (bagder) Date: 2009-04-05 20:18 Message: libssh2_poll() seems to be fundamentally flawed. I suggest we just call it deprecated and tell people to use poll() instead! Can you (or anyone else) provide a use case where the normal poll() or select() isn't good enough or better? ---------------------------------------------------------------------- Comment By: Paul Thomas (thomaspu) Date: 2008-10-02 04:22 Message: I think the problem stems around line 1525 of channel.c. Looks like if we call the channel_read function, we expect to read data from a call to libssh2_packet_read() and if we don't read anything from that function call, we don;t read anything period. However, the code doesn't check the packet list to see if there's packets in it waiting to be read. ---------------------------------------------------------------------- Comment By: Paul Thomas (thomaspu) Date: 2008-10-02 04:12 Message: This one was written up by me, I just forgot to log in again! ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=703942&aid=2141548&group_id=125852 ------------------------------------------------------------------------------ This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com _______________________________________________ libssh2-devel mailing list libssh2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libssh2-devel
