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Tidied up bind-dirs.md

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Moved example to config-files.md
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unman 2019-06-06 16:35:08 +00:00
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user/advanced-configuration/bind-dirs.md
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@ -19,32 +19,38 @@ In a TemplateBasedVM all of the file system comes from the template except `/hom
This means that changes in the rest of the filesystem are lost when the TemplateBasedVM is shutdown.
bind-dirs provides a mechanism whereby files usually taken from the template can be persisted across reboots.
For example, in Whonix, [Tor's data dir /var/lib/tor has been made persistent in the TemplateBased ProxyVM sys-whonix](https://github.com/Whonix/qubes-whonix/blob/8438d13d75822e9ea800b9eb6024063f476636ff/usr/lib/qubes-bind-dirs.d/40_qubes-whonix.conf#L5).
For example, in Whonix, [Tor's data dir /var/lib/tor has been made persistent in the TemplateBased ProxyVM sys-whonix][whonix]
In this way sys-whonix can benefit from the Tor anonymity feature 'persistent Tor entry guards' but does not have to be a StandaloneVM.
## How to use bind-dirs.sh? ##
Inside your TemplateBasedVM.
In this example, we want to make /var/lib/tor persistent.
Inside the TemplateBasedVM.
1. Make sure folder `/rw/config/qubes-bind-dirs.d` exists.
sudo mkdir -p /rw/config/qubes-bind-dirs.d
2. Create a file `/rw/config/qubes-bind-dirs.d/50_user.conf` with root rights inside a TemplateBasedVM.
2. Create a file `/rw/config/qubes-bind-dirs.d/50_user.conf` with root rights.
3. Edit the file 50_user.conf to append a folder or file name to the `binds` variable. (In the following example we are using folder `/var/lib/tor`. You can replace that name with a folder or file name of your choice.)
3. Edit the file 50_user.conf to append a folder or file name to the `binds` variable.
binds+=( '/var/lib/tor' )
Multiple entries are possible, each on a separate line.
4. Save.
5. Reboot the TemplateBasedVM.
6. Done.
If you added for example folder `/var/lib/tor` to the `binds` variable, from now on any files within that folder will persist reboots. If you added for example file `/etc/tor/torrc` to the `binds` variable, from now on any modifications to that file will persist reboots.
From now on any files within the/var/lib/tor folder will persist across reboots.
You can make make many files or folders persist, simply by making multiple entries in the p50_user.conf file, each on a separate line.
For example, if you added the file `/etc/tor/torrc` to the `binds` variable, any modifications to *that* file will persist across reboots.
binds+=( '/var/lib/tor' )
binds+=( '/etc/tor/torrc' )
## Other Configuration Folders ##
@ -54,35 +60,31 @@ If you added for example folder `/var/lib/tor` to the `binds` variable, from now
## How does it work? ##
bind-dirs.sh is called on startup of a TemplateBasedVM, and configuration files in the configuration folders above are parsed to build a bash array.
bind-dirs.sh is called at startup of a TemplateBasedVM, and configuration files in the above configuration folders are parsed to build a bash array.
Files or folders identified in the array are copied to /rw/bind-dirs if they do not already exist there, and are then bind mounted over the original files/folders.
Creation of the file and folders in /rw/bind-dirs should be automatic the first time the TemplateBasedVM is restarted after configuration.
Creation of the files and folders in /rw/bind-dirs should be automatic the first time the TemplateBasedVM is restarted after configuration.
If you want to circumvent this process, you can create the relevant filestructure under /rw/bind-dirs and make any changes at the same time that you perform the configuration, before reboot.
Note that you must create the full folder structure under /rw/bind-dirs - e.g you would have to create /rw/bind-dirs/var/lib/tor
If you want to circumvent this process, you can create the relevant filestructure under /rw/bind-dirs and make any changes at the same time that you perform the configuration, before reboot.
## Limitations ##
* Files that exist in the TemplateVM root image cannot be deleted in the TemplateBasedVMs root image using bind-dirs.sh.
* Re-running `sudo /usr/lib/qubes/bind-dirs.sh` without a previous `sudo /usr/lib/qubes/bind-dirs.sh umount` does not work.
* Running `sudo /usr/lib/qubes/bind-dirs.sh umount` after boot (before shutdown) is probably not sane and nothing can be done about that.
* Re-running `sudo /usr/lib/qubes/init/bind-dirs.sh` without a previous `sudo /usr/lib/qubes/init/bind-dirs.sh umount` does not work.
* Running `sudo /usr/lib/qubes/init/bind-dirs.sh umount` after boot (before shutdown) is probably not sane and nothing can be done about that.
* Many editors create a temporary file and copy it over the original file. If you have bind mounted an individual file this will break the mount.
Any changes you make will not survive a reboot. If you think it likely you will want to edit a file, then either include the parent directory in bind-dirs rather than the file, or perform the file operation on the file in /rw/bind-dirs.
* Some files are altered when a qube boots - e.g. `/etc/hosts`. If you try to use bind-dirs on such files you may break your qube in unpredictable ways.
You can add persistent rules to `/etc/hosts` file using script `/rw/config/rc.local` that is designed to override configuration in /etc, starting services and etc. For example, to make software inside some TemplateBasedVM resolving the domain `example.com` as `127.0.0.1` open `/rw/config/rc.local` inside this TemplateBasedVM and add:
~~~
echo '127.0.0.1 example.com' >> /etc/hosts
~~~
After every boot of the TemplateBasedVM `rc.local` script will add line `127.0.0.1 example.com` to `/etc/hosts` file and the software inside the TemplateBasedVM will resolve domain `example.com` accordingly. You cam add several rules to `/etc/hosts` the same way.
* Some files are altered when a qube boots - e.g. `/etc/hosts`.
If you try to use bind-dirs on such files you may break your qube in unpredictable ways.
You can add persistent rules to /etc/hosts using [/rw/config/rc.local][config-file]
## How to remove binds from bind-dirs.sh? ##
`binds` is actually just a bash variable (an array) and the bind-dirs.sh configuration folders are `source`d as bash snippets in lexical order.
`binds` is actually just a bash variable (an array) and the bind-dirs.sh configuration folders are sourced as bash snippets in lexical order.
Therefore if you wanted to remove an existing entry from the `binds` array, you could do that by using a lexically higher configuration file.
For example, if you wanted to make `/var/lib/tor` non-persistant in `sys-whonix` without manually editing [`/usr/lib/qubes-bind-dirs.d/40_qubes-whonix.conf`](https://github.com/Whonix/qubes-whonix/blob/master/usr/lib/qubes-bind-dirs.d/40_qubes-whonix.conf), you could use the following.
For example, if you wanted to make `/var/lib/tor` non-persistent in `sys-whonix` without manually editing /usr/lib/qubes-bind-dirs.d/40_qubes-whonix.conf, you could use the following in:
`/rw/config/qubes-bind-dirs.d/50_user.conf`
@ -96,3 +98,5 @@ binds=( "${binds[@]/'/var/lib/tor'}" )
[TemplateBasedVMs: make selected files and folders located in the root image persistent- review bind-dirs.sh](https://groups.google.com/forum/#!topic/qubes-devel/tcYQ4eV-XX4/discussion)
[config-file]: /doc/config-files
[whonix]: https://github.com/Whonix/qubes-whonix/blob/8438d13d75822e9ea800b9eb6024063f476636ff/usr/lib/qubes-bind-dirs.d/40_qubes-whonix.conf#L5

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user/advanced-configuration/config-files.md
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@ -29,6 +29,11 @@ The scripts here all run as root.
ln -s /rw/config/var-lib-bluetooth /var/lib/bluetooth
~~~
~~~
# Add entry to /etc/hosts
echo '127.0.0.1 example.com >> /etc/hosts
~~~
- `/rw/config/qubes-ip-change-hook` - script runs in NetVM after every external IP change and on "hardware" link status change.
- In ProxyVMs (or AppVMs with `qubes-firewall` service enabled), scripts placed in the following directories will be executed in the listed order followed by `qubes-firewall-user-script` after each firewall update.