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<title>Berkeley DB Reference Guide: VxWorks FAQ</title>
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<table width="100%"><tr valign=top>
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<td><h3><dl><dt>Berkeley DB Reference Guide:<dd>Building Berkeley DB for VxWorks systems</dl></h3></td>
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<td align=right><a href="../../ref/build_vxworks/notes.html"><img src="../../images/prev.gif" alt="Prev"></a><a href="../../reftoc.html"><img src="../../images/ref.gif" alt="Ref"></a><a href="../../ref/upgrade/version.html"><img src="../../images/next.gif" alt="Next"></a>
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<h1 align=center>VxWorks FAQ</h1>
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<p><li><b>I get the error "Workspace open failed: This project workspace is an
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older format.", when trying to open the supplied workspace on Tornado
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<p>This error will occur if the files were extracted in a manner that adds
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a CR/LF to lines in the file. Make sure that you download the Berkeley DB
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".zip" version of the Berkeley DB distribution, and, when extracting the Berkeley DB
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sources, that you use an unzipper program that will not do any
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<p><li><b>How can I build Berkeley DB without using Tornado?</b>
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<p>The simplest way to build Berkeley DB without using Tornado is to configure
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Berkeley DB on a UNIX system, and then use the Makefile and include files
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generated by that configuration as the starting point for your build.
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The Makefile and include files are created during configuration, in the
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current directory, based on your configuration decisions (for example,
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debugging vs. non-debugging builds), so you'll need to configure the
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system for the way you want Berkeley DB to be built.
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<p>Additionally, you'll need to account for the slight difference between
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the set of source files used in a UNIX build and the set used in a
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VxWorks build. You can use the following command to create a list of
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the Berkeley DB VxWorks files. The commands assume you are in the build_vxworks
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directory of the Berkeley DB distribution:
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<p><blockquote><pre>% cat > /tmp/files.sed
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s/<BEGIN> FILE_//
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% grep FILE_ BerkeleyDB.wpj | grep _objects | sed -f /tmp/files.sed > /tmp/db.files</pre></blockquote>
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<p>You will then have a template Makefile and include files, and a list of
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VxWorks-specific source files. You will need to convert this Makefile
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and list of files into a form that is acceptable to your specific build
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<p><li><b>Can I run the test suite under VxWorks?</b>
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<p>The test suite requires the Berkeley DB Tcl library. In turn, this library
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requires Tcl 8.1 or greater. In order to run the test suite, you would
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need to port Tcl 8.1 or greater to VxWorks. The Tcl shell included in
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<i>windsh</i> is not adequate for two reasons. First, it is based on
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Tcl 8.0. Second, it does not include the necessary Tcl components for
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adding a Tcl extension.
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<p><li><b>Are all Berkeley DB features available for VxWorks?</b>
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<p>All Berkeley DB features are available for VxWorks with the exception of the
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<a href="../../api_c/db_open.html#DB_TRUNCATE">DB_TRUNCATE</a> flag for <a href="../../api_c/db_open.html">DB->open</a>. The underlying mechanism
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needed for that flag is not available consistently across different file
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<p><li><b>Are there any constraints using particular filesystem drivers?</b>
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<p>There are constraints using the dosFs filesystems with Berkeley DB. Namely,
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you must configure your dosFs filesystem to support long filenames if
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you are using Berkeley DB logging in your application. The VxWorks' dosFs
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1.0 filesystem, by default, uses the old MS-DOS 8.3 file-naming
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constraints, restricting to 8 character filenames with a 3 character
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extension. If you have configured with VxWorks' dosFs 2.0 you should
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be compatible with Windows FAT32 filesystems which supports long
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<p><li><b>Are there any dependencies on particular filesystem drivers?</b>
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<p>There is one dependency on specifics of filesystem drivers in the port
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of Berkeley DB to VxWorks. Berkeley DB synchronizes data using the FIOSYNC function
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to ioctl() (another option would have been to use the FIOFLUSH function
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instead). The FIOSYNC function was chosen because the NFS client driver,
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nfsDrv, only supports it and doesn't support FIOFLUSH. All local file
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systems, as of VxWorks 5.4, support FIOSYNC -- with the exception of
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rt11fsLib, which only supports FIOFLUSH. To use rt11fsLib, you will need
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to modify the os/os_fsync.c file to use the FIOFLUSH function; note that
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rt11fsLib cannot work with NFS clients.
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<p><li><b>Are there any known filesystem problems?</b>
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<p>During the course of our internal testing, we came across two problems
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with the dosFs 2.0 filesystem that warranted patches from Wind River Systems.
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You should ask Wind River Systems for the patches to these
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problems if you encounter them.
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<p>The first problem is that files will seem to disappear. You should
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look at <b>SPR 31480</b> in the Wind River Systems' Support pages for
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a more detailed description of this problem.
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<p>The second problem is a semaphore deadlock within the dosFs filesystem
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code. Looking at a stack trace via CrossWind, you will see two or more of
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your application's tasks waiting in semaphore code within dosFs. The patch
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for this problem is under <b>SPR 33221</b> at Wind River Systems.
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<p><li><b>Are there any filesystems I cannot use?</b>
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<p>The Target Server File System (TSFS) uses the netDrv driver. This driver
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does not support any ioctl that allows flushing to the disk, and therefore
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cannot be used with Berkeley DB.
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<p><li><b>Why aren't the utility programs part of the project?</b>
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<p>The utility programs, in their UNIX-style form, are not ported to VxWorks.
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The reasoning is the utility programs are essentially wrappers for the
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specific Berkeley DB interface they call. Their interface and generic model
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are not the appropriate paradigm for VxWorks. It is most likely that
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specific applications will want to spawn tasks that call the appropriate
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Berkeley DB function to perform the actions of some utility programs, using
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VxWorks native functions. For example, an application that spawns several
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tasks that all may operate on the same database would also want to spawn
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a task that calls <a href="../../api_c/lock_detect.html">lock_detect</a> for deadlock detection, but specific
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to the environment used for that application.
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<p><li><b>What VxWorks primitives are used for mutual exclusion in Berkeley DB?</b>
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<p>Mutexes inside of Berkeley DB use the basic binary semaphores in VxWorks. The
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mutexes are created using the FIFO queue type.
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<p><li><b>What are the implications of VxWorks' mutex implementation
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using microkernel resources?</b>
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<p>On VxWorks, the semaphore primitives implementing mutexes consume system
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resources. Therefore, if an application unexpectedly fails, those
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resources could leak. Berkeley DB solves this problem by always allocating
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mutexes in the persistent shared memory regions. Then, if an
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application fails, running recovery or explicitly removing the database
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environment by calling the <a href="../../api_c/env_remove.html">DB_ENV->remove</a> function will allow Berkeley DB to
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release those previously held mutex resources. If an application
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specifies the <a href="../../api_c/env_open.html#DB_PRIVATE">DB_PRIVATE</a> flag (choosing not to use persistent
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shared memory), and then fails, mutexes allocated in that private memory
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may leak their underlying system resources. Therefore, the
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<a href="../../api_c/env_open.html#DB_PRIVATE">DB_PRIVATE</a> flag should be used with caution on VxWorks.
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