UELD ---- Usermode Environment Loader Daemon

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Ueld (Usermode Environment Loader Daemon) is a lightweight init program under Unix/Linux environment, it can be used to replace SysVInit and Systemd

Compile and install

Unstable branch may contain useful fixes or exciting changes, you can use git Version Control switch to unstable branch. But this will be quite dangerous, because the unstable branch code has not been fully tested.

$ git checkout unstable

To compile and install

$ cd path-to-ueld-src
$ ./mkconfig.sh
$ make
$ sudo make install

On FreeBSD, you need use gmake instead of make. Compiling ueld need GNU Make.

The installation requires root user, so sudo(8) is used in this example. If you do not have sudo(8) in your system, use other methods to switch to Root.

You can use the PREFIX variable to set the root file system. You can use the INSTALLDIR variable to set the installation directory.

Note: When you use both PREFIX and INSTALLDIR, the install path is ${PREFIX}/${INSTALLDIR}, in other word, INSTALLDIR should not include the path prefix.

Compiletime config

Before you compile ueld, you need do 'compiletime config' by ./mkconfig.sh, it will generate a config.h header which includes config macros. Run mkconfig.sh without args will make a header which includes default config.

For example, if you need not Multi-Init feature, you can

$ ./mkconfig.sh --no-build-in-minit

For more infomation, please see this Wiki

Cross compile

If you want to cross-compile Ueld, you can use the CROSS variable to set the cross compiler name, for example, if you want to use 'arm-linux-gnueabihf-' cross compiler, you can

$ make CROSS=arm-linux-gnueabihf-

Install for a linux system which does not use initramfs (or initrd).

Some systems do not use initramfs. That means ueld should mount some filesystems by itself. To install ueld for these system, you need

$ sudo make install_no_initramfs

Install sysvinit-compat version for linux system (Obsolete)

If you want to use sysvinit style services, you can

$ sudo make install_sysv_compat

For more infomation, please see this Wiki

Configure and use Ueld

After the installation, I suggest you configure Ueld immediately, refer to this Wiki

Ueld manual is also included in this wiki; Uninstallation instructions are also included in this wiki.

If you first install Ueld on Linux, then the Ueld configuration file is set to create getty(8) on tty1-5 to wait for login, which may not be suitable for your situation, so do not forget to configure it. Noteworthy, when you install Ueld, if the configuration file in the corresponding directory is already exists, it will not overwrite the previous configuration file, even if the new version of the default configuration may be changed.

But on FreeBSD, the Ueld configuration file will run /etc/rc and then ctreate getty, so you may have no request to modify them.

Install Examples

Now, we have some examples to show how to install ueld on your system!

Install on Ubuntu 16.04.1

Install on FreeBSD

TODO

• Port ueld to other Unix systems. (Platform related code is placed in the os/ subdirectory. The init program itself determines that the characteristics of the different platforms have to make a lot of differences in the code.)

• Support escaped characters and quotation marks in ueld.conf and respawn.list.

• Desktop environment support. That need use dbus service to get messages (such as poweroff) and run ueldctl. Do not add the support into ueld daemon process.

• Hash table for respwan process.

• Ueld subreaper for user (like upstart --user or systemd --user), for Linux 3.4+.

• Ueld system service system.

• Clean dirty codes.

• See the 'TODO' and 'FIXME' marks in code.