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a tinybsd build. If we do not do this, we can accidentally remove critical files from directories like /lib (if mounted). PR: misc/121763 Submitted by: Richard Arends < richard at unixguru dot nl > MFC after: 3 days |
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# $FreeBSD$ - TinyBSD You must read this to know how to build embedded systems with TinyBSD. - TinyBSD files TinyBSD's creation conf files are available under /usr/src/tools/tools/tinybsd/conf and the script are available under /usr/src/tools/tools/tinybsd/tinybsd. The system has been entirely based on the ease of image customization from PicoBSD, and the compilation script based on NanoBSD's. # ls /usr/src/tools/tools/tinybsd/conf bridge/ default/ firewall/ minimal/ vpn/ wireless/ wrap/ We have these six pre configured images to build. On each directory we have 3 main files in there. Let's see what each of them are: # ls /usr/src/tools/tools/tinybsd/conf/default TINYBSD etc/ tinybsd.basefiles TINYBSD: Just like PicoBSD had its kernel previously compiled, we call ours TINYBSD. # more TINYBSD machine i386 cpu I486_CPU cpu I586_CPU cpu I686_CPU ident TINYBSD #To statically compile in device wiring instead of /boot/device.hints #hints "GENERIC.hints" #Default places to look for devices. ... As you can see, it's a kernel file identical to your system's, leaving only the task of enabling or disabling options, according to your needs. tinybsd.basefiles: Just like PicoBSD had its crunch.conf file to define which files we'd want the new system to have, in this one we'll have all files to be put into our embedded system, already having all available files for running the system well. Put in or take out the files you need according to your needs. Let's see it: # more tinybsd.basefiles # contents of ${WORKDIR}/boot boot/boot0 boot/boot1 boot/boot2 boot/defaults/loader.conf boot/device.hints ... # contents of ${WORKDIR}/bin bin/[:bin/test bin/cat bin/chflags bin/chio bin/chmod ... And so on. In case you'd want to add the binary "setkey", sitting on /usr/sbin, you'd only need to add the following line inside the /usr/sbin part of the file, like this: usr/sbin/pw usr/sbin/pwd_mkdb usr/sbin/setkey tinybsd.ports: Here you can add the applications from the FreeBSD Ports Collection which you want TinyBSD ports system to install in your embedded system. You whould list one application per line, mentioning its category and name, like the examples: www/mini_httpd net-mgmt/rate etc/: This is the directory where you can put your custom /etc configuration. # ls /usr/src/tools/tools/tinybsd/tinybsd tinybsd tinybsd: This is the script that builds the entire system. You'll hardly need to modify it at all. The idea is for it to create a temporary work directory for it to create the entire system tree. Once done, it'll copy all files listed in tinybsd.basefiles to this tree, then it'll compile a new kernel using the definitions in the TINYBSD file, and finally copy the library dependencies the binaries will have. We'll then populate /etc on that temporary tree and put in a few important default configurations inside on /usr/src/tools/tools/tinybsd/conf/YOURCHOICE/etc/ like rc.conf, fstab and others. Finally, we create an empty image, according to your media's specifications, passed on to the script on the command line, and copy the entire temporary work tree into the image mounted on /mnt. - Running TinyBSD Now that we know how it works, it's time for us to build our own image. Let's do that step-by-step. 1) Choose what pre-configured image you want. 2) Edit the TINYBSD kernel file and add/remove all options you'll need. 3) Edit the tinybsd.basefiles file and add/remove all binaries you'll need on your system. 4) Copy all your /etc configuration wich you want to conf/YOURIMAGE/etc/. 5) Gather the right information on your destination media. To do that, plug in the device on the system and fetch the information using diskinfo(8): # diskinfo -v /dev/ad2 ad2 512 # sectorsize 20060135424 # mediasize in bytes (19G) 39179952 # mediasize in sectors 38869 # Cylinders according to firmware. 16 # Heads according to firmware. 63 # Sectors according to firmware. To create my image, I'll need to know the media size in sectors, Heads according to firmware and Sectors according to firmware. Optionally, you may define the name of the generated image's file, but if you don't, it'll be named tinybsd.bin. Now that we have gathered these informations through diskinfo, all we need to do is run tinybsd. Remember that it has 3 parameters plus 1 optional, and if you don't pass on the required ones, the script will warn you about it: # /usr/src/tools/tools/tinybsd/tinybsd Woops! Usage: tinybsd <mediasize in sectors> <heads according to firmware> <sectors according to firmware> <conf> [<tinybsd image name>] Example: tinybsd 62592 4 32 or /usr/src/tools/tools/tinybsd/tinybsd 62592 4 32 wireless Run diskinfo(8) -v against your CF device to get correct information about your disk. Passing on the parameters correctly: # /usr/src/tools/tools/tinybsd/tinybsd 39179952 16 63 wireless Creating directory hierarchy... ./bin missing (created) ./boot missing (created) ./boot/defaults missing (created) ./boot/kernel missing (created) ./boot/modules missing (created) ./dev missing (created) ./etc missing (created) ... In the end, we have the generated tinybsd.bin image. Now we have to copy it to its final destination: # dd if=/usr/src/tools/tools/tinybsd/tinybsd.bin of=/dev/ad2 Boot up your new embedded system and log on it. If you're ever going to modify it, you must first remount the root slice as read-write, as it operates by default on read-only mode, saving disk writes and preventing data-loss in case of power failures. To mount it for read-write, use mount: # mount -u -o rw / Once you're done, return it to read-only mode: # mount -u -o ro / The first thing you need to do after logging for the first time, is to set a root password. By default, it's created with no root password. If you run df(1), you'll see the following partitions: # df Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/ad0a 29359 19446 7565 72% / devfs 1 1 0 100% /dev procfs 4 4 0 100% /proc /dev/md0 3694 114 3286 3% /var /dev/md1 19566 6 17996 0% /tmp As you can see, /var and /tmp are mounted on /dev/md0 and /dev/md1 respectively, using memory disk devices. That's because both /var and /tmp are write-intensive, and as our system works mostly on read-only mode, we'd suffer with writing problems there, so the memory disk approach works fine. On the other hand, whenever you reboot the system, those directories' contents (including logs on /var/log) will be lost. If you need to keep the contents of those directories, I suggest you to always upload them to another box. The configuration line that fires up the system script to create /var as a memory disk partition is "varmfs="YES"", inside /etc/rc.conf. Besides mounting /var as a memory disk device, it also populates its tree with the necessary subdirectories. Initially, /var is created on memory using only 32MB of space, and that's usually enough. Although, if you find it necessary to tweak that configuration, you may edit this line of /etc/rc.conf: varsize="32m" Change 32m to whatever value you see fit (in MBytes). Take care of not using your entire memory for /var. - Ports and TinyBSD You can also install ports on the new system via ports. For that, you'll need to set the PREFIX environment variable to the image's destination path. Let's assume you want to install apache on the newly-created image. For that, I'd do this: # mdconfig -a -t vnode -f /usr/src/tools/tools/tinybsd/tinybsd.bin -u 0 That uses mdconfig to enable the memory disk 0. # mount /dev/md0a /mnt Now we've mounted the image on the temporary directory /mnt. Let's then install apache via ports: # cd /usr/ports/www/apache13 # make install PREFIX=/mnt/usr/local ===> Vulnerability check disabled >> apache_1.3.31.tar.gz doesn't seem to exist in /usr/ports/distfiles/. >> Attempting to fetch from http://www.apache.org/dist/httpd/. ... This port has installed the following startup scripts which may cause these network services to be started at boot time. /mnt/usr/local/etc/rc.d/apache.sh .... Once the install is finished, let's verify that apache has indeed been properly installed under our /mnt directory: # cd /mnt/usr/local/sbin # ls -lga httpd -rwxr-xr-x 1 root wheel 252439 Jul 14 15:31 httpd Our software has been successfully installed. You must notice that at the end of the install, it shows the full path for the PREFIX variable we passed it. The problem with that is that at boot-time, your system is going to look for it under /mnt instead of /usr. So we need to edit apache's initialization script under /usr/local/etc/rc.d (apache.sh) and remove all instances of "/mnt" in it. WARNING: A very important thing to care about are dependencies. Before installing anything, check to see if it has any dependencies, and that you'll have enough disk space on the destination system for both the application you're installing and its dependencies. - Script download TinyBSD is still a project under heavy development, both the script itself and its documentation. In case you'd like to try or use the BETA version of the script, feel free to download it from the project's official site at http://www.tinybsd.org.