Category Archives: Ports Collection

Algorithm to detect repo-copies in CVS

FreeBSD is on its way to move from CVS to SVN  for the version control system for the Ports Collection. The decision was made to keep the complete history, so the complete CVS repository has to be converted to SVN.

As CVS has no way to record a copy or move of files inside the repository, we copied the CVS files inside the repository in case we wanted to copy or move a file (the so called “repocopy”). While this allows to see the full history of a file, the drawback is that you do not really know when a file was copied/moved if you are not strict at recording this info after doing a copy. Guess what, we where not.

Now with the move to SVN which has a build-in way for copies/moves, it would be nice if we could record this info. In an internal discussion someone told its not possible to detect a repocopy reliably.

Well, I thought otherwise and an hour later my mail went out how to detect one. The longest time was needed to write how to do it, not to come up with a solution. I do not know if someone picked up this algorithm and implemented something for the cvs2svn converter, but I decided to publish the algorithm here if someone needs a similar functionality somewhere else. Note, the following is tailored to the structure of the Ports Collection. This allows to speed up some things (no need to do all steps on all files). If you want to use this in a generic repository where the structure is not as regular as in our Ports Collection, you have to run this algorithm on all files.

It also detects commits where multiple files where committed at once in one commit (sweeping commits).

Preparation

  • check only category/name/Makefile
  • generate a hash of each commitlog+committer
  • if you are memory-limited use ha/sh/ed/dirs/cvs-rev and store pathname in the list cvs-rev (pathname = “category-name”) as storage
  • store the hash also in pathname/cvs-rev

If you have only one item in ha/sh/ed/dirs/cvs-rev in the end, there was no repocopy and no sweeping commit, you can delete this ha/sh/ed/dirs/cvs-rev.

If you have more than … let’s say … 10 (subject to tuning) pathnames in ha/sh/ed/dirs/cvs-rev you found a sweeping commit and you can delete the ha/sh/ed/dirs/cvs-rev.

The meat

The remaining ha/sh/ed/dirs/cvs-rev are probably repocopies. Take one ha/sh/ed/dirs/cvs-rev and for each pathname (there may be more than 2 pathnames) in there have a look at pathname/. Take the first cvs-rev of each and check if they have the same hash. Continue with the next rev-number for each until you found a cvs-rev which does not contain the same hash. If the number of cvs-revs since the beginning is >= … let’s say … 3 (subject to tuning), you have a candidate for a repocopy. If it is >=  … 10 (subject to tuning), you have a very good indicator for a repocopy. You have to proceed until you have only one pathname left.

You may detect multiple repocopies like A->B->C->D or A->B + A->D + A->C here.

Write out the repocopy candidate to a list and delete the ha/sh/ed/dirs/cvs-rev for each cvs-rev in a detected sequence.

This finds repocopy candidates for category/name/Makefile. To detect the correct repocopy-date (there are maybe cases where another file was changed after the Makefile but before the repocopy), you now have to look at all the files for a given repocopy-pair and check if there is a matching commit after the Makefile-commit-date. If you want to be 100% sure, you compare the complete commit-history of all files for a given repocopy-pair.

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Alexander Leidinger

Seems I forgot to announce that the linux_base-c6 is in the Ports Collection now. Well, it is not a replacement for the current default linux base, the linuxulator infrastructure ports are missing and we need to check if the kernel supports enough of 2.6.18 that nothing breaks.

TODO:

To my knowledge, nobody is working on anything of this. Anyone is welcome to have a look and provide patches.

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New CentOS linux_base for testing soonish

It seems my HOWTO create a new linux_base port was not too bad. There is now a PR for a CentOS 6 based linux_base port. I had a quick look at it and it seems that it is nearly usable to include into the Ports Collection (the SRPMs need to be added, but that can be done within some minutes).

When FreeBSD 8.3 is released and the Ports Collection open for sweeping commits again, I will ask portmgr to do a repo-copy for the new port and commit it. This is just the linux_base port, not the complete infrastructure which is needed to completely replace the current default linuxulator userland. This is just a start. The process of switching to a more recent linux_base port is a long process, and in this case depends upon enough support in the supported FreeBSD releases.

Attention: Anyone installing the port from the PR should be aware that using it is a highly experimental task. You need to change the linuxulator to impersonate himself as a linux 2.6.18 kernel (described in the pkg-message of the port), and the code in FreeBSD is far from supporting this. Anyone who wants to try it is welcome, but you have to run FreeBSD-current as of at least the last weekend, and watch out for kernel messages about unsupported syscalls. Reports to [email protected] please, not here on the webpage.

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HOWTO add linux-infrastructure ports for a new linux_base port

In my last blog-post I described how to create a new linux_base port. This blog-post is about the other Linux–ports which make up the Linux–infrastructure in the FreeBSD Ports Collection for a given Linux-release.

What are linux-infrastructure ports?

A linux_base port contains as much as possible and at the same time as little as possible to make up a useful Linux-compatibility-experience in FreeBSD. I know, this is not a descriptive explanation. And it is not on purpose. There are no fixed rules what has to be inside or what not. It “matured

HOWTO create a new linux_base port

FreeBSD is in need of a new linux_base port. It is on my TODO list since a long time, but I do not get the time to create one. I still do not have the time to work on a new one, but when you read this, I managed to get the time to create a HOWTO which describes what needs to be done to create a new linux_base port.

I will not describe how to create a new linux_base port from scratch, I will just describe how you can copy the last one and update it to something newer based upon the existing infrastructure for RPM packages.

Specific questions which come up during porting a new Linux release should be asked on [email protected],  there are more people which can answer questions than here in my blog. I will add useful information to this HOWTO if necessary.

In the easy case most of the work is searching the right RPMs and their dependencies to use, and to create the plist.

Why do we need a new linux_base port?

The current linux_base port is based upon Fedora 10, which is end of life since December 2009. Even Fedora 13 is already end of life. Fedora 16 is supposed to be released this year. From a support point of view, Fedora 15 or maybe even Fedora 16 would be a good target for the next linux_base port. Other alternatives would be to use an extended lifetime release of another RPM based distribution, like for example CentOS 6 (which seems to be based upon Fedora 12 with backports from Fedora 13 and 14). Using a Linux release which is told to be supported for at least 10 years, sounds nice from a FreeBSD point of view (only minor changes to the linux ports in such a case, instead of creating a complete new linux_base each N+2 releases like with Fedora), but it also means additional work if you want to create the first linux_base port for it.

The mysteries you have to conquer if you want to create a new linux_base port

What we do not know is, if Fedora 15/16, CentOS 6, or any other Linux release will work in a supported FreeBSD release. There are two ways to find this out.

The first one is to take an existing Linux system, chroot into it (either via NFS or after making a copy into a directory of a FreeBSD system), and to run a lot of programs (acroread, skype, shells, scripts, …). The LTP testsuite is not that much useful here, as it will test mostly kernel features, but we do not know which kernel features are mandatory for a given userland of a Linux release.

The second way of testing if a given Linux release works on FreeBSD is to actually create a new linux_base port for it and test it without chrooting.

The first way is faster, if you are only interested in testing if something works. The second way provides an easy to setup testbed for FreeBSD kernel developers to fix the Linuxulator so that it works with the new linux_base port. Both ways have their merits, but it is up to the person doing the work to decide which way to go.

The meat: HOWTO create a new linux_base port

First off, you need a system (or a jail) without any linux_base port installed. After that you can create a new linux_base port (= lbN), by just making a copy of the latest one (= lbO). In lbN you need to add lbO as a CONFLICT, and in all other existing linux_base ports, you need to add lbN as a conflict.

Change the PORTNAME, PORTVERSION, reset the PORTREVISION in lbN, and set LINUX_DIST_VER  to the new Linux-release version in the lbN Makefile (this is used in PORTSDIR/Mk/bsd.linux-rpm.mk and PORTSDIR/Mk/bsd.linux-apps.mk).

If you do not stay with Fedora, there is some more work to do before you can have a look at chosing RPMs for installation. You need to have a look at PORTSDIR/Mk/bsd.linux-rpm.mk and add some cases for the new LINUX_DIST you want to use. Do not forget to set LINUX_DIST in the lbN Makefile to the name of the distribution you use. You also need to augment the LINUX_DIST_VER check in PORTSDIR/Mk/bsd.linux-rpm.mk with some LINUX_DIST conditionals. If you are lucky, the directory structure for downloads is similar to the Fedora structure, and there is not a lot to do here.

When this is done, you can have a look at the BIN_DISTFILES variable in the lbN Makefile. Try to find similar RPMs for the new Linux release you want to port. Some may not be available, and it may also be the case that different ones are needed instead. I suggest to first work with the ones which are available (make makesum, test install and create plist). After that you need to find out what the replacement RPMs for non-existing ones are. You are on your own here. Search around the net, and/or have a look at the dependencies in the RPMs of lbO to determine if something was added as a dependency of something else or not (if not, forget about it ATM). When you managed to find replacement RPMs, you can now have a look at the dependencies of the RPMs in lbN. Do not add blindly all dependencies, not all are needed in FreeBSD (the linux_base ports are not supposed to create an environment which you can chroot into, they are supposed to augment the FreeBSD system to be able to run Linux programs in ports like they where FreeBSD native programs). What you need in the linux_base ports are libraries, config and data files which do not exist in FreeBSD or have a different syntax than in FreeBSD (those config or data files which are just in a different place, can be symlinked), and basic shell commands (which commands are needed or not… well… good question, in the past we made decisions what to include based upon problem reports from users). Now for the things which are not available and where not added as a dependency. Those are things which are either used during install, or where useful to have in the past. Find out by what it was replaced and have a look if this replacement can easily be used instead. If it can be used, add it. If not, well… bad luck, we (the FreeBSD community) will see how to handle this somehow.

If you think that you have all you need in BIN_DISTFILES, please update SRC_DISTFILES accordingly and generate the distfile via  make –DPACKAGE_BUILDING makesum to have the checksums of the sources (for legal reasons we need them on our mirrors).

The next step is to have a look at REMOVE_DIRS, REMOVE_FILES and ADD_DIRS if something needs to be modified. Most of them are there to fall back to the corresponding FreeBSD directories/files, or because they are not needed at all (REMOVE_*). Do not remove directories from ADD_DIRS, they are created here to fix some edge conditions (I do not remember exactly why we had to add them, and I do not take the time ATM to search in the CVS history).

If you are lucky, this is all (make sure the plist is correct). If you are not lucky and you need to make some modifications to files, have a look at the do-build target in the Makefile, this is the place where some changes are done to create a nice user experience.

If you arrive here while creating a new linux_base port, lean back and feel a bit proud. You managed to create a new linux_base port. It is not very well tested at this moment, and it is far from everything which needs to be done to have the complete Linux infrastructure for a given Linux release, but the most important part is done. Please notify [email protected] and call for testers.

What is missing?

The full Linuxulator infrastructure for the FreeBSD Ports Collection has some more ports around a linux_base port. Most of the infrastructure for this is handled in Mk/bsd.linux-apps.mk.

UPDATE: I got some time to write how to update the Linux-infrastructure ports.

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Converting from Courier IMAP to dovecot is easy

I have used Courier IMAP at home since a long time. As I want to update a dovecot 1.2 setup to dovecot 2.x, I decided to first have a look at dovecot 2.x at home.

Switching from Courier IMAP to dovecot is really easy. I just configured the correct path to the maildir, setup a passdb/userdb, and it was working.

The important part was the correct transfer of the passwords. I used already an userdb in Courier IMAP with MD5 passwords. For each user it has imappw=XXX with XXX similar to $1$abc.

This can be converted into a dovecot passdb/userdb line very easily:

username:{MD5-CRYPT}$1$abc::UID:GID::HOMEDIR::userdb_mail=maildir:~/path/to/maildir

The corresponding passdb/userdb settings for dovecot are:

passdb {
   args = scheme=MD5-CRYPT username_format=%u /usr/local/etc/dovecot/dovecot.pws
   driver = passwd-file
}
userdb {
   args = username_format=%u /usr/local/etc/dovecot/dovecot.pws
   driver = passwd-file
}

Compared to when I had a look the last time, dovecot is also able to use OTP as an authentication mechanism now. Unfortunately I did not find any documentation how to configure/use it.

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Non-default linux base ports deprecated

Yesterday I deprecated the non-default Fedora based Linux base ports. This means fc6, f7, f8 and f9 will vanish soon (I decided for one month of expiry time). This is because all of them are End of Life upstream since a long time (= no security updates).

The fc4 and f10 ones are still available — even if they are End of Life too — because FreeBSD 7.x can not use something newer than the fc4 one, and we have not tested yet a more recent Linux distribution.

Probably the most easy way to update the Linux base ports to something newer is to stay with Fedora (we have a lot of ports-infrastructure for it already). Unfortunately it is not known if something newer works without problems (missing epoll/inotify support could be a roadblock here in case it is extensively used in a more recent version).

I want to get some time to have a look if a more recent Fedora version is suitable for the use as a Linux base in FreeBSD 8.x+, but I do not have an estimate when I can start and how long it may take. In case someone already tested a more recent Fedora version feel free to share your experience.

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HOWTO: creating your own updated linux RPM for the FreeBSD linuxulator

Background info

The FreeBSD linux compatibility environment currently uses RPMs from Fedora 10. Unfortunately Fedora 10 is end of life since a while. For one of the RPMs (the pango one) we where aware of a security vulnerability. As we do not know if it is feasible to update the linuxulator ports to something more recent, I decided to setup a VM with Fedora 10 and generate a new RPM for the linux-f10-pango port. Thanks to Luchesar V. ILIEV for explaining me how to do this.

Setup of the VM

I used VirtualBox 4.0.4 on a Solaris 10 x86 machine. I configured a fixed size disk of 16 GB and kept the default network setup (after installing the guest tools / kernel modules I switched to virtio, as I was not able to do anything useful besides a ping) and RAM size. The CD/DVD drive was configured to use the image of the full Fedora 10 DVD for i386 systems.

Setup of Fedora 10

Booting the VM from the DVD leads to the graphical Fedora 10 install software (after chosing to install a new system on the console). There I accepted all the defaults, except for the software to install. I deselected the Office and Productivity group and selected the Software Development group. When I was asked if I want to install some additional RPMs I had a look at the complete list and installed some I thought are necessary. I do not remember anymore which ones I chose, but everything which looks related to RPM building is a good candidate.

After a while the install will be finished and you can boot into the new system (eject the DVD from the drive before reboot). After reboot chose to install the Guest Additions in the menu of the VM. This should mount the ISO image in the VM. As root execute the file for Linux. This will build some kernel modules for better integration (e.g. seamless integration of the mouse between your desktop and the VM). At this point I rebooted and configured virtio as the NIC. I also had to configure the network settings by hand, as the GUI tool did not safe all the settings correctly.

Update and install of required RPMs

After the VM was up and the network configured, I updated the entire system (chose System Update in the menu). To update the pango port, I had to install the libthai-devel RPM. I had the RPM for it (and all the files I need to build a new pango RPM) already downloaded, so I did a “yum install /path/to/rpm

A new linux-f10-pango port is ready

In the last days I took (and even had) the time to install a VM with Fedora 10, updated all the packages after installation, and created a new linux-f10-pango port (v 1.28.3). I did this because the port has a security vulnerability according to our VuXML DB and there where more and more reports in the last months from users which had a problem with this.

During the update of the port I noticed that the port does not contain a FORBIDDEN entry, just portaudit complains about it because there is an entry in the VuXML. That is not nice. I was told that the ports slush will be lifted soon (I need to bump some PORTREVISIONs), this means that I can commit the update probably tomorrow, just in time when the new RPM should hit the FreeBSD distribution infrastructure (MASTER_SITE_LOCAL is updated once a day from a specific folder in our home directories).

Thanks to Luchesar V. ILIEV for the nice writeup of what to install in Fedora 10 to be able to build RPMs, and the description of how to build your own RPM.

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Weather station readout with FreeBSD

A while ago a wind turbine was installed not far away from my place. It is far enough to not disturb us, and it is near enough to notice that it turns a lot (IIRC I have seen it only once not turning).

This triggered a question. How much energy would such a device (smaller of course) produce at my place?

The answer depends upon several factors. The wind speed, the wind direction and the wind-speed-to-power-output curve of the device. If you do not take a device which rotates around the horizontal axis but the vertical axis, the wind direction can be taken out of the question (probably not completely, but to answer my question this simplification should be ok). The output-power curve depends upon the device, and I hope it is easy to get it from the vendors. The remaining open question it the wind speed at my place. Is there enough wind with enough speed?

To answer this question I bought a weather station with an anemometer (wind speed sensor). I searched a little bit until I decided to buy a specific one (actually I bought three of them, some coworkers got interested too but they found only much more expensive ones, so soon there will be three more weather stations in use in Belgium, France and Germany). The main point is, I can connect it to an USB port of a PC and there is some software for Linux to read out the data. It also comes with some other outdoor-sensors (temperature, rain, wind direction, humidity, …) and an indoor-control-unit with some internal sensors (temperature, humidity). The user interface is mainly the touchscreen of the control-unit. There is also some Windows software, which is needed to program the interval in which the measurements are taken and saved in the control-unit.

It seems the weather station is produced by Fine Offset Electronics Co.,Ltd and sold within different brands in different locations. The Linux software can read all of them, as the vendor and product IDs are not changed.

Porting the software was easy, it uses libusb and I just had to correct a little problem for the non-portable functions which are used (I asked about them on usb@ and the response was that they just got implemented upon my request and will be committed to HEAD soon). I made a little patch for the software to only use them when available (if you have not loaded the USB HID driver, you do not need to care about them) and committed it to the Ports Collection as astro/fowsr.

Now I just need to attach the outside sensors at the place where I would put the vertical axis wind turbine, install some toolkit which takes a series of measurements and displays them as a nice graph (while keeping all data values) and write some glue code to feed the output of fowsr to it. After a year I can then calculate how much power a given wind turbine would have produced during the year and calculate the return of investment for it.

The Linux software also references several weather sites, for some of them you can get even an iGoogle widget so that you can view the data from wherever you want (as long as you have a suitable internet connection). I think this is also something I will have a look at later.

Note to users in Europe, the device also comes with a DCF77 receiver. As the time is distributed in UTC+1 (or +2, depending on the daylight saving time), you should adjust the timezone setting accordingly to this, not to plain UTC (so for me the timezone should be ‘0’ for the same timezone).

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Direct, indirect and explicit dependencies in progams/ports

The discussion about direct and indirect dependencies is coming up again on the FreeBSD mailinglists. Seems I should make some blog post about it, maybe it makes this topic more findable than my postings in the mailinglists.

Some definitions:

  • A direct dependency from A to B is when program/port A uses symbols from library/port B.
  • An indirect dependency from A to C is when program/port A uses symbols from library/port B but no symbols from library/port C, and library/port B uses symbols from library/port C.
  • An explicit dependency from A to C is when it is a direct or indirect dependency A to C, and when the compiler-time-linker added an explicit reference to C to the program/lib of A.

Ideally we have no indirect dependencies in the explicit dependencies, only direct dependencies. Unfortunately in reality we also have indirect dependencies there. This has at least two causes:

  1. libtool (at least 1.x) does not (or was not) come with a hint on FreeBSD, which tells that the run-time-linker is recursively resolving dependencies.
  2. Some pkg-config setups list indirect dependencies as explicit dependencies (IIRC it depends if Requires.private and/or Libs.private is used in the .pc file or not; if it is used, there should be no indirect dependency appear from this software, but I am not 100% sure about this).

Three years ago I wrote /usr/ports/Tools/scripts/explicit_lib_depends.sh, it looks at the files of a given port (it needs to be installed), and prints out explicit dependencies. Because of the indirect dependencies which could be listed there, this list is not a list of ports which are real dependencies from a source code point of view, but it reflects the link-time reality. If a port C shows up there, the port which is checked needs to be rebuild in case the ABI of library/port C changes.

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LAME updated in the FreeBSD ports collection

After all the big-impact commits (Gnome/gettext/KDE/X11/…) have settled now, I took the time to update audio/lame (I identified more than 100 ports with an (implicit) dependency on lame, 45 of them needed a portrevision bump; if I forgot/overlooked some, bump the revision yourself or notify me please). That is the first update of my ports where miwi@ did not beat me in committing an update since a year (he has implicit approval to do anything he wants with my ports).

I can be happy that he is/was this fast (and that we have such a productive and efficient committer), or I can be sad that I do not have the time anymore to be faster than I am with such things… or both. Hmmm… I think I will go the happy way. ;-)

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Cheap process monitoring (no additional software required)

I have an old system (only the hardware, it runs –current) which reboots itself from time to time (mostly during the daily periodic(8) run, but also during a lot of compiling (portupgrade)). There is no obvious reason (no panic) why it is doing this. It could be that there is some hardware defect, or something else. It is not important enough to get a high enough priority that I try hard to analyze the problem with this machine. The annoying part is, that sometimes after a restart apache does not start. So if this happens, the solution is to login and start the webserver. If the webserver would start each time, nearly nobody would detect the reboot (root gets an EMail on each reboot via an @reboot crontab entry).

My pragmatic solution (for services started via a good rc.d script which has a working status command) is a crontab entry which checks periodically if it is running and which restarts the service if not. As an example for apache and an interval of 10 minutes:

*/10 * * * *    /usr/local/etc/rc.d/apache22 status >/dev/null 2>&1 || /usr/local/etc/rc.d/apache22 restart

For the use case of this service/machine, this is enough. In case of a problem with the service, a mail with the restart output would arrive each time it runs, else only after a reboot for which the service did not restart.