Alexander Leidinger

Just another weblog

Dec
03

Updat­ing FreeBSD 8.2 (or 9.x) to 10 (beta4)

This is a lit­tle descrip­tion how I remotely (no con­sole, booted into multi-user dur­ing update, no exter­nal ser­vices like jails/httpd/… run­ning) updated a FreeBSD 8.2 to 10 (beta4) from source. This should also work when updat­ing from FreeBSD 9.x. Note, I had already switched to ATA_CAM on 8.2, so not instruc­tions for the name change of the ata devices. No IPv6, WLAN or CARP is in use here, so changes which are needed in this area are not cov­ered. Read UPDATING care­fully, there are a lot of changes between major releases.

What I did:

  • update /usr/src
  • make build­world
  • replace “make ” in /usr/src/Makefile.inc1 with ${MAKE} (two times, one for “VERSION”, one for “BRANCH”)
  • ver­ify ker­nel con­fig for changes needed (run­ning “con­fig MyK­er­nel” in /usr/src/sys/YourArch/conf/ helps to iden­tify syn­tax prob­lems), sorry I didn’t take notes, but I diffed the old and the new GENERIC con­fig and added/removed accord­ing to my interests
  • /usr/obj/…/src/usr.bin/bmake/make build­ker­nel KERNCONF=MyKernel
  • /usr/obj/…/src/usr.bin/bmake/make instal­lk­er­nel KERNCONF=MyKernel KODIR=/boot/kernel.10
  • merge­mas­ter –p
  • /usr/obj/…/src/usr.bin/bmake/make install­world DESTDIR=/somewhere/test
  • mkdir /root/net10; cp /somewhere/test/rescue/ifconfig /somewhere/test/rescue/route /root/net10
  • cre­ate the file /etc/rc.10update with:
    case $(uname –r) in
    8.2*)
            MYIFCONFIG=/sbin/ifconfig
            MYROUTE=/sbin/route
            ;;
    10*)
            MYIFCONFIG=/root/net10/ifconfig
            MYROUTE=/root/net10/route
            ;;
    esac
    export MYIFCONFIG
    export MYROUTE
  • change the files (stu­pid approach: grep for “ifcon­fig” and “route” in /etc/rc.d to iden­tify files which need to change, I skipped files which I iden­ti­fied as not needed in my case, if you use pf/IPv6/bridge/…, you may have to change some more files) /etc/rc.d/auto_linklocal /etc/rc.d/defaultroute /etc/rc.d/netif /etc/rc.d/netwait /etc/rc.d/routing: add “. /etc/rc.10update” at the end of the block with “. /etc/rc.subr”, change the “ifconfig”-command to ${MYIFCONFIG}, change the “route”-command to ${MYROUTE}
  • change /etc/net­work.subr: add “. /etc/rc.10update” before the first func­tion, change the “ifconfig”-command to ${MYIFCONFIG}, change the “route”-command to ${MYROUTE}
  • make sure that the changes you made are 100% cor­rect, rather triple-check than to not check at all (you will be locked out if they are not 100% OK)
  • stop any jails and make sure they do not restart at boot
  • deac­ti­vate the gmir­ror of the root-fs, if there is one (it is maybe eas­ier to ask a remote hand to swap the boot order in case of problems)
  • here you could just a reboot of the server to come back to your cur­rent OS ver­sion, so make sure that the mod­i­fi­ca­tions in /etc did not cause any prob­lems with the old ver­sion (in case you see prob­lems with the v10 ker­nel), but if you do not have a remote con­sole to single-user mode you have no chance to directly fix the prob­lem (risk mit­i­ga­tion described above), no mat­ter which ver­sion of the ker­nel you boot
  • next­boot –k kernel.10
  • shut­down –r now
  • login
  • check dmesg
  • optional: mv /boot/kernel /boot/kernel.8
  • make instal­lk­er­nel KERNCONF=MyKernel
    to have a v10 /boot/kernel
  • make install­world
  • merge­mas­ter
  • make delete-old
  • rm –r /etc/rc.10update /root/net10
  • change rc.conf: add “inet” in ifconfig-aliases
  • review sysctl.conf for out­dated entries
  • shut­down –r now
  • optional: rm –r /boot/kernel.10
  • enable jails again (or later… updat­ing jails is not described here)
  • activate/resync mirror(s)
  • rebuild all ports (atten­tion: new pkg system)
  • make delete-old-libs
  • reboot again to make sure every­thing is OK after the port-rebuild and removal of old libs (a console.log (syslog.conf) helps here
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Dec
23

Cal­cu­lat­ing the tar­get size of H264 videos

From time to time I con­vert videos to H264. When I do this I want to get the best qual­ity out of a give file­size. This means I cre­ate VBR videos. The ques­tion here is, how big the tar­get video file shall be.

After search­ing around a lit­tle bit in the net I found a for­mula which is sup­posed to give a hint about the tar­get file­size. Nat­u­rally this depends on the encoder (or even the encoder-version), the encoder set­tings and even the video.

The for­mula is at least a good hint for my use, so I wrote a script which cal­cu­lates sev­eral file­size val­ues for a given video (based upon the out­put of medi­ainfo, which the scripts expects in a file with the file­name as an argu­ment to the script). It cal­cu­lates a CBR and a VBR value for a given video based upon the width, height and dura­tion. It should work on all sys­tem with a POSIX com­pat­i­ble shell.

Exam­ple out­put for a video from my HD-ready cam, orig­i­nal file­size 1.8 GB:

Width: 1280, Height: 720, FPS: 50.000, Time: 1424, Motion: 2
Per sec­ond: 6451200.000 bps / 6300 Kibps
Total CBR: 1148313600 bytes / 1121400 KiB / 1095 MiB
Total VBR: 861235200 bytes / 841050 KiB / 821 MiB
Width: 1280, Height: 720, FPS: 50.000, Time: 1424, Motion: 3
Per sec­ond: 9676800.000 bps / 9450 Kibps
Total CBR: 1722470400 bytes / 1682100 KiB / 1642 MiB
Total VBR: 1291852800 bytes / 1261575 KiB / 1232 MiB
Width: 1280, Height: 720, FPS: 50.000, Time: 1424, Motion: 4
Per sec­ond: 12902400.000 bps / 12600 Kibps
Total CBR: 2296627200 bytes / 2242800 KiB / 2190 MiB
Total VBR: 1722470400 bytes / 1682100 KiB / 1642 MiB

There are 3 sec­tions, the dif­fer­ence is the “motion” value. It is a kind of mul­ti­pli­ca­tor depend­ing on the amount of motion in the video. For the videos I made myself (fam­ily videos, and even some videos of vol­ley ball games), the first sec­tion seems to be just fine. So I reduced the orig­i­nal MP4 file to about 50% (not vis­i­ble here is the audio size, nor­mally I copy the orig­i­nal audio unmodified).

For the curi­ous ones, the for­mula is

width_in_pixels * height_in_pixels * fps * motion_value * 0.07

for the bps value. The CBR value is

bps * playtime_in_seconds / 8

and the VBR value is

3 / 4 * CBR_value.

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Jun
15

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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May
31

Free DLNA server which works good with my Sony BRAVIA TV

In sev­eral pre­vi­ous posts I wrote about my quest for the right source for­mat to stream video to my Sony BRAVIA TV (build in 2009). The last week-end I finally found some­thing which sat­is­fies me.

What I found was serviio, a free UPnP-AV (DLNA) server. It is writ­ten in java and runs on Win­dows, Linux and FreeBSD (it is not listed on the web­site, but we have an not-so-up-to-date ver­sion in the ports tree). If nec­es­sary it transcodes the input to an appro­pri­ate for­mat for the DLNA ren­derer (in my case the TV).

I tested it with my slow Net­book, so that I was able to see with which input for­mat it will just remux the input con­tainer to a MPEG trans­port stream, and which input for­mat would be really re-encoded to a for­mat the TV understands.

The bot­tom line of the tests is, that I just need to use a sup­ported con­tainer (like MKV or MP4 or AVI) with H.264-encoded video (e.g. encoded by x264) and AC3 audio.

The TV is able to chose between sev­eral audio streams, but I have not tested if serviio is able to serve files with mul­ti­ple audio streams (my wife has a dif­fer­ent mother lan­guage than me, so it is inter­est­ing for us to have mul­ti­ple audio streams for a movie), and I do not know if DLNA sup­ports some­thing like this.

Now I just have to replace minidlna (which only works good with my TV for MP3s and Pic­tures) with serviio on my FreeBSD file server and we can for­get about the disk-juggling.

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Feb
03

What you should know about SSH

Michael W. Lucas pub­lished his new book “SSH Mas­tery” (no link to an online store, get it from your pre­ferred online or offline one in your part of the world).

Do you think you know a lot about SSH? I thought I did when Michael searched tech­ni­cal proof-readers for this book. I offered to have a look at his work in progress and he gen­tly accepted (while I do not get money for this, I am one of the per­sons he thanks for  the tech­ni­cal review in the begin­ning, so I am involved some­how and as such you should take the fol­low­ing with a grain of salt).

I already had user restric­tions in place before the review, but now I nar­rowed down some restric­tions based upon some con­di­tion­als. I already used SSH tun­nels for var­i­ous things before (where legally applic­a­ble), but I learned some addi­tional VPN tech­niques with SSH. I already used mul­ti­ple ssh-keys for var­i­ous things, but Michael pro­vides some inter­est­ing ways of han­dling a large-volume of ssh-keys over mul­ti­ple machines. … I really hope that my review was as valu­able for Michael, as it was for me to do the review.

He ends the book with “You now know more about SSH, OpenSSH and Putty than the vast major­ity of IT pro­fes­sion­als! Con­grat­u­la­tions”, and this is true, and all that in his writ­ing style where you can come with a prob­lem, read about it, and leave with a solu­tion (nor­mally with a lit­tle bit of enter­tain­ment in between).

I know a lot of peo­ple which work daily with SSH, and they know only a small part of what is pre­sented in this book. In my opin­ion this book is a must-have for every System/Database/Application/Whatever Admin­is­tra­tor in charge of some­thing on an UNIX-like sys­tem, and even “nor­mal users” of SSH (no mat­ter if they use PuTTY, or a ssh com­mand line pro­gram on an UNIX-like sys­tem (most prob­a­bly it will be OpenSSH or a clone of it)) will get some help­ful infor­ma­tion from this book.

I can only rec­om­mend it.

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