Subject: SmbFile.exists( "smb://server" ) - msg#00123

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Re: threading

On Sun, Feb 23, 2003 at 12:31:06AM -0500, Dan Dumont wrote: > That's fine with me, perhaps I did not make my intentions clear. I > don't mind if it blocks the thread. What I do mind is that it blocks > all other threads trying to connect also. > > The whole program locks up while I wait for one thread to connect. That's because blocking occurs at the host OS process level. I *believe* that when a Java thread performs an operation that causes the JVM to call a blocking system call, the entire JVM instance (which exists as a single OS thread) will block. This may depend upon the implementation, since some implementations may behave differently (that is, they may implement threading differently). I am doing a bit of guessing here, based on my earlier experience with blocking DNS lookups under Java (many years ago). Here's an interesting reference I stumbled upon: http://www.cs.berkeley.edu/~mdw/proj/java-nbio/ Chris -)----- -- Samba Team -- http://www.samba.org/ -)----- Christopher R. Hertel jCIFS Team -- http://jcifs.samba.org/ -)----- ubiqx development, uninq. ubiqx Team -- http://www.ubiqx.org/ -)----- crh@xxxxxxxxxxxx OnLineBook -- http://ubiqx.org/cifs/ -)----- crh@xxxxxxxxx

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Re: threading

On Sat, 22 Feb 2003 23:21:22 -0600 "Christopher R. Hertel" <crh@xxxxxxxxxxxx> wrote: > So the thread is calling a blocking syscall, and thus blocking all other > threads as well... Is that correct? No. That should not happen with native threads. If threads are handled entirely in userspace it will but not with native kernelspace threads. Actually there are different thread models that might utilize a mixture of userspace and kernelspace threads so in theory a blocking syscall like a read could block other threads but I've never actually seen this happen. Mike -- A program should be written to model the concepts of the task it performs rather than the physical world or a process because this maximizes the potential for it to be applied to tasks that are conceptually similar and, more important, to tasks that have not yet been conceived.

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listFiles() problem - Access denied

Hello everyone!   I get the following exception when I execute the SmbFile.listFiles() on "smb://myworkgroup/" :   jcifs.smb.SmbAuthException: Access denied  at jcifs.smb.SmbTransport.send(SmbTransport.java:494)  at jcifs.smb.SmbSession.sessionSetup(SmbSession.java:126)  at jcifs.smb.SmbSession.send(SmbSession.java:102)  at jcifs.smb.SmbTree.treeConnect(SmbTree.java:132)  at jcifs.smb.SmbFile.connect(SmbFile.java:522)  at jcifs.smb.SmbFile.connect0(SmbFile.java:484)  at jcifs.smb.SmbFile.sendTransaction(SmbFile.java:460)  at jcifs.smb.SmbFile.listFiles(SmbFile.java:1304)  at jcifs.smb.SmbFile.listFiles(SmbFile.java:1237)  at IPDialog$LanScanner.run(IPDialog.java:882)   On other workgroups in the same LAN, I dont get this exception, only on "myworkgroup". I suspect that some server(s) are not accessible, at all, at least without a proper authentication.   I would be very happy if the listFiles() method would return only the accessible servers and leave the others out. What I mean is, why not get i.e. the 5 out of the 6 servers of "myworkgroup" and leave the 1 out?   Why should "listFiles()" return "ALL" or "NOTHING" ? Why not "SOME" ?      

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Re: SmbFile.exists( "smb://server" )

On Sun, 23 Feb 2003 00:36:30 -0600 "Christopher R. Hertel" <crh@xxxxxxxxxxxx> wrote: > I was fiddling with the Exists.java tool in the examples directory and > noticed that when given a URL with just a server name it sends a name > query. That is: > > $ java Exists smb://server > > sends a broadcast name query for SERVER<20>. > > Now, that is a valid test on a broadcast NBT network. If a response to > the broadcast is received it means that there is a node claiming that > name. > > Unfortuantely, I don't have my network set up for WINS testing at the > moment. What I want to know is this: If WINS is in use, does the Exists > test query the WINS server and, if so, what does it do afterward? This is all described pretty well here: http://jcifs.samba.org/src/docs/resolver.html > See, the problem I'm concerned about is that a name may exist in the WINS > database even though the machine that registered the name has been shut > down. Good behavior is that a cleanly shut-down system would release the > name first, but that doesn't always happen and some WINS implementations > are flakey. So the proper test would be to send an Adapter Status query > following the WINS lookup to verify the name. No, we don't do that. If you look at UniAddress.getByName and consider the jcifs.netbios.wins and jcifs.resolveOrder property and what they do the name resolution capability of jCIFS is second to none. It is equally good at finding a good "called name". If an IP is giving it may do a node status although only as a last resort. Again see UniAddress.java. Mike -- A program should be written to model the concepts of the task it performs rather than the physical world or a process because this maximizes the potential for it to be applied to tasks that are conceptually similar and, more important, to tasks that have not yet been conceived.