A Bash script wrapper for utility proot for easy management of chroot-based Linux distribution installations. It does not require root or any special ROM, kernel, etc. Everything you need to get started is the latest version of Termux application. See Installing for details.
PRoot Distro is not a virtual machine, neither a traditional chroot. It shares the same kernel as your Android system, so do not even try to update it through package manager - this will not work.
This script should never be run as root user. If you do so, file permissions
and SELinux labels could get messed up. There also possibility of damaging
system if being executed as root. For safety, PRoot Distro checks the user id
before run and refuses to work if detected user id 0
(root).
PRoot Distro provides support only one version of distribution types, i.e. one of stable, LTS or rolling-release. Support of versioned distributions ended with branch 2.x. If you need a custom version, you will need to add it on your own. See Adding distribution.
Here are the supported distributions (alias: name):
alpine
: Alpine Linux (edge)archlinux
: Arch Linux ARMdebian
: Debian (stable)fedora
: Fedora 37 (AArch64 only)manjaro-aarch64
: Manjaro AArch64opensuse
: OpenSUSE (Tumbleweed)pardus
: Pardus (yirmiuc)ubuntu
: Ubuntu (22.04)void
: Void Linux
All systems come in a bare-minimum variant, typically consisting of package manager, shell, coreutils, util-linux and few more. Extended functionality like shell completion or package install suggestions should be configured manually.
With package manager:
pkg install proot-distro
With git:
pkg install git
git clone https://github.com/termux/proot-distro
cd proot-distro
./install.sh
Dependencies: bash, bzip2, coreutils, curl, findutils, gzip, ncurses-utils, proot, sed, tar, xz-utils
PRoot Distro aims to provide all-in-one functionality for managing the installed distributions: installation, de-installation, backup, restore, login. Each action is defined through command. Each command accepts its unique set of options, specific to the task that it performs.
Usage basics:
proot-distro <command> <arguments>
Where <command>
is a proot-distro action command (see below to learn what
is available) and <arguments>
is a list of options specific to given command.
Example of installing the distribution:
proot-distro install debian
Known distributions are defined through plug-in scripts, which define URLs from where root file system archive will be downloaded and set of checksums for integrity check. Plug-ins also can define a set of commands which would be executed during distribution installation.
See Adding distribution to learn more how to add own distribution to PRoot Distro.
Command: help
This command will show the help information about proot-distro
usage.
proot-distro help
- main page.proot-distro <command> --help
- view help for specific command.
Command: backup
Backup specified distribution and its plug-in into tar archive. The contents of backup can be either printed to stdout for further processing or written to a file.
Compression is determined according to file extension, e.g..tar.gz
will lead
to GZip compression and .tar.xz
will lead to XZ. Piped backup data is always
not compressed giving user freedom for further processing.
Usage example:
proot-distro backup debian | xz | ssh example.com 'cat > /backups/pd-debian-backup.tar.xz'
proot-distro backup --output backup.tar.gz debian
This command is generic. All additional processing like encryption should be done by user through external commands.
Command: install
Install a distribution specified by alias - a short name referring to the plug-in of chosen distribution.
Usage example:
proot-distro install alpine
By default the installed distribution will have same alias as specified on
command line. This means you will be unable to install multiple copies at
same time. You can rename distribution during installation time by using
option --override-alias
which will create a copy of distribution plug-in.
Usage example:
proot-distro install --override-alias alpine-test alpine
proot-distro login alpine-test
Copied plug-in has following name format <name>.override.sh
and is stored
in directory with others ($PREFIX/etc/proot-distro
).
Command: list
Shows a list of available distributions, their aliases, installation status and comments.
Command: login
Execute a shell within the given distribution. Example:
proot-distro login debian
Execute a shell as specified user in the given distribution:
proot-distro login --user admin debian
You can run a custom command as well:
proot-distro login debian -- /usr/local/bin/mycommand --sample-option1
Argument --
acts as terminator of proot-distro login
options processing.
All arguments behind it would not be treated as options of PRoot Distro.
Login command supports these behavior modifying options:
-
--user <username>
Use a custom login user instead of default
root
. You need to create the user viauseradd -U -m username
before using this option. -
--fix-low-ports
Force redirect low networking ports to a high number (2000 + port). Use this with software requiring low ports which are not possible without real root permissions.
For example this option will redirect port 80 to something like 2080.
-
--isolated
Do not mount host volumes inside chroot environment. If this option was given, following mount points will not be accessible inside chroot:
- /apex (only Android 10+)
- /data/dalvik-cache
- /data/data/com.termux
- /sdcard
- /storage
- /system
- /vendor
You will not be able to use Termux utilities inside chroot environment.
-
--termux-home
Mount Termux home directory as user home inside chroot environment.
This option takes priority over option
--isolated
. -
--shared-tmp
Share Termux temporary directory with chroot environment. Takes priority over option
--isolated
. -
--bind path:path
Create a custom file system path binding. Option expects argument in the given format:
<host path>:<chroot path>
Takes priority over option
--isolated
. -
--no-link2symlink
Disable PRoot link2symlink extension. This will disable hard link emulation. You can use this option only if SELinux is disabled or is in permissive mode.
-
--no-sysvipc
Disable PRoot System V IPC emulation. Try this option if you experience crashes.
-
--no-kill-on-exit
Do not kill processes when shell session terminates. Typically will cause session to hang if you have any background processes running.
Command: remove
This command completely deletes the installation of given system. Be careful as it does not ask for confirmation. Deleted data is irrecoverably lost.
Usage example:
proot-distro remove debian
Command: rename
Rename the distribution by changing the alias name, renaming its plug-in and root file system directory. In case when default distribution is being renamed, a copy of plug-in will be created.
Usage example:
proot-distro rename ubuntu ubuntu-test01
Only installed distribution can be renamed.
Command: reset
Delete the specified distribution and install it again. This is a shortcut for
proot-distro remove <dist> && proot-distro install <dist>
Usage example:
proot-distro reset debian
Same as with command remove
, deleted data is lost irrecoverably. Be careful.
Command: restore
Restore the distribution from the given proot-distro backup (tar archive).
Restore operation performs a complete rollback to the backup state as was in archive. Be careful as this command deletes previous data irrecoverably.
Compression is determined automatically from file extension. Piped data
must be always uncompressed before being supplied to proot-distro
.
Usage example:
ssh example.com 'cat /backups/pd-debian-backup.tar.xz' | xz -d | proot-distro restore
proot-distro restore ./pd-debian-backup.tar.xz
Command: clear-cache
This will remove all cached root file system archives.
Distribution is defined through the plug-in script that contains variables with metadata. A minimal one would look like this:
DISTRO_NAME="Debian"
TARBALL_URL['aarch64']="https://github.com/termux/proot-distro/releases/download/v1.10.1/debian-aarch64-pd-v1.10.1.tar.xz"
TARBALL_SHA256['aarch64']="f34802fbb300b4d088a638c638683fd2bfc1c03f4b40fa4cb7d2113231401a21"
Script is stored in directory $PREFIX/etc/proot-distro
and should be named
like <alias>.sh
, where <alias>
is a desired name for referencing the
distribution. For example, Debian plug-in will typically be named debian.sh
.
DISTRO_ARCH
: specifies which CPU architecture variant of distribution to
install.
Normally this variable is determined automatically, and you should not set it. Typical use case is to set a custom architecture to run the distribution under QEMU emulator (user mode).
Supported architectures are: aarch64
, arm
, i686
, x86_64
.
DISTRO_NAME
: a name of distribution, something like "Alpine Linux (3.14.1)".
DISTRO_COMMENT
: comments for current distribution.
Normally this variable is not needed. Use it to notify user that something is not working or additional steps required to get started with this distribution.
TARBALL_STRIP_OPT
: how many leading path components should be stripped when
extracting rootfs archive. The default value is 1 because all default rootfs
tarballs store contents in a subdirectory.
TARBALL_URL
: a Bash associative array of root file system tarballs URLs.
Should be defined at least for your CPU architecture. Valid architecture names
are same as for DISTRO_ARCH
.
TARBALL_SHA256
: a Bash associative array of SHA-256 checksums for each rootfs
variant.
Must be defined for each tarball set in TARBALL_URL
.
Plug-in can be configured to execute specified commands after installing the
distribution. This is done through function distro_setup
.
Example:
distro_setup() {
run_proot_cmd apt update
run_proot_cmd apt upgrade -yq
}
run_proot_cmd
is used when command should be executed inside the rootfs.
While PRoot is often referred as user space chroot implementation, it is much different from it both by implementation and features of work. Here is a list of most significant differences you should be aware of.
-
PRoot is slow.
Every process is hooked through
ptrace()
, so PRoot can hijack the system call arguments and return values. This is typically used to translate file paths so traced program will see the different file system layout. -
PRoot cannot detach from the running process.
Since PRoot controls the running processes via
ptrace()
it cannot detach from them. This means you can't start a daemon process (e.g. sshd) and close PRoot session. You will have to either kill process, wait until it finish or let proot kill it immediately on session close. -
PRoot does not elevate privileges.
Chroot also does not elevate privileges on its own. Just PRoot is configured to hijack user id as well, i.e. make it appear as
root
. So in reality your user name, id and privileges remain to be same as without PRoot but programs that do sanity check for current user will assume you are running as root user.Particularly, the fake root user makes it possible to use package manager in chroot environment.
If you wish to use PRoot Distro or its part as a base for your own project, please make sure you comply with GNU GPL v3.0 license.