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Touch up the README a little.

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libudev-zero
============
# libudev-zero
Drop-in replacement for `libudev` that enables you to use any device manager
you like without worrying about the `udev` dependency at all!
Drop-in replacement for libudev enables you to use any device manager you like
without worrying about udev dependency at all!
## Why?
Because `udev` sucks, it is bloated and overengineered. `udev` is just like `systemd`, it locks you into using non-portable crap that you can't avoid because multiple programs depend on it. Look, even FreeBSD was forced to rewrite[1] this crappy library because `libinput` hard-depends on `udev`. Without `libinput` you can't use `wayland` and many other cool stuff.
Why ?
Michael Forney (author of `cproc`, `samurai`, Oasis Linux, ...) decided to fork[2] `libinput` and remove the hard dependency on `udev`. Is this a solution? Yes.
Is this a complete solution? No. This fork has a lot of disadvantages like requiring patching applications to use `libinput_netlink` instead of the `libinput_udev` API in order to use the automatic detection of input devices and hotplugging. Static configuration is also required for anything other than input devices (e.g drm devices). Moreover hotplugging is vulnerable to race conditions when `libinput` handles the `uevent` faster than the device manager which can lead to file permission issues. `libudev-zero` prevents these race conditions by design.
Because udev sucks, bloated and overengineered. udev is just like
systemd, lock you into using non-portable crap that you can't avoid
because many software depends on it. Look, even FreeBSD was forced to
rewrite[1] this crappy library because libinput has mandatory udev dependency.
Without libinput you can't use wayland and some other cool stuff.
Michael Forney (cproc, samurai, Oasis Linux, ... author) decided to fork[2]
libinput and remove udev mandatority. This is solution ? Yes. This is complete
solution ? No. This fork has a lot of disadvantages like requiring patching
application from libinput_udev to libinput_netlink API in order to use
automatic detection of input devices and hotplugging. Static confuguration also
required for anything other than input devices (e.g drm devices). Moreover
hotplugging vulnerable to race conditions when libinput handles uevent faster
than device manager which can lead to file permissions issues. libudev-zero
prevents these race conditions by design.
Thanks god udev has stable API and hopefully no changes will be made in
future. On this basis i decided to create this clean-room implementation of
libudev which can be used with any or without device manager.
Thankfully `udev` has stable API and hopefully no changes will be made to it the future. On this basis I decided to create this clean-room implementation of `libudev` which can be used with any or without a device manager.
[1] https://github.com/FreeBSDDesktop/libudev-devd
[2] https://github.com/oasislinux/libinput
What Works
----------
## What Works
* [x] xorg-server
* [ ] dosfstools - need implement udev_enumerate_add_match_parent()
* [ ] dosfstools - need to implement udev_enumerate_add_match_parent()
* [x] libinput
* [x] usbutils
* [x] wlroots
@@ -42,79 +24,52 @@ What Works
* [x] kwin - [fix](https://github.com/dilyn-corner/KISS-kde/commit/0cc72748e46f859a0fced55b0c3fcc1dd9586a38)
* [ ] ???
Dependencies
------------
## Dependencies
* C99 compiler (build time)
* POSIX make (build time)
* POSIX & XSI libc
* epoll & inotify
* Linux >= 2.6.39
Installation
------------
## Installation
```sh
make
make PREFIX=/usr install # will overwrite existing udev libraries if any
# rebuild all packages which depends on udev
# here we go !
make PREFIX=/usr install # this will overwrite udev libraries if they exist
# rebuild all the packages that depend on libudev, and you're ready to go.
```
Hotplugging
-----------
## Hotplugging
Note that hotplugging support is fully optional! You can skip this step if you don't have a need for the hotplugging capability.
Note that hotplugging support is fully optional! You can skip this step if you
don't have anything to hotplug.
Hotplugging is fairly uncomplicated and not overengineered at all. Everything is portable as much as possible. To use hotplugging the only thing you need is a `uevent` receiver (like a device manager, busybox's `uevent`, `CONFIG_UEVENT_HELPER`, ...). I will explain only the `mdev` and `CONFIG_UEVENT_HELPER` methods because their usage is fairly basic. For busybox's `uevent` you need to write your own parser which is kinda, well, complex.
There is no complicated or overengineered way to use hotplugging. Everything is
portable as much as possible. To use hotplugging the only thing you need is
uevent's receiver (device manager, busybox `uevent`, CONFIG_UEVENT_HELPER, ...).
I will describe only mdev and CONFIG_UEVENT_HELPER because their usage is very basic.
For busybox `uevent` you need to write your own parser which is kinda ... complex.
`UDEV_MONITOR_DIR` is an arbitrary directory where the `uevent` files are stored. The default is `/tmp/.libudev-zero`. You can change it at build time by appending `-DUDEV_MONITOR_DIR=<dir>` to `CFLAGS`. I don't recommend setting `UDEV_MONITOR_DIR` to regular filesystems (i.e non-tmpfs) because temporary files aren't automatically discarded after reboot or termination (yet).
UDEV_MONITOR_DIR is arbitrary directory where uevent files stored.
Default is `/tmp/.libudev-zero`. You can change it at build time by appending
`-DUDEV_MONITOR_DIR=<dir>` to CFLAGS. I don't recommend setting UDEV_MONITOR_DIR
to regular fs (i.e non-tmpfs) because unneeded files aren't automatically discarded
after reboot or termination (yet).
### a) the `mdev` method
1. merge [mdev.conf](contrib/mdev.conf) with your `mdev.conf`
2. restart the `mdev` daemon
1. mdev
### b) the `CONFIG_UEVENT_HELPER` method
1. ensure that `CONFIG_UEVENT_HELPER` is enabled in your kernel configuration
2. add the directory containing [helper.sh](contrib/helper.sh) after marking it as executable or [helper.c](contrib/helper.c) after compiling it, to `/proc/sys/kernel/hotplug`
- merge [mdev.conf](contrib/mdev.conf) with your mdev.conf
- restart mdev daemon
#### example:
```sh
echo "/full/path/to/helper" > /proc/sys/kernel/hotplug # will use the default UDEV_MONITOR_DIR
OR
echo "/full/path/to/helper <dir>" > /proc/sys/kernel/hotplug # change <dir> to your UDEV_MONITOR_DIR
```
1. CONFIG_UEVENT_HELPER
- ensure that CONFIG_UEVENT_HELPER enabled in kernel
- add full path of [helper.sh](contrib/helper.sh) (must be executable) or
[helper.c](contrib/helper.c) (compile it first) to /proc/sys/kernel/hotplug
example:
```sh
echo /full/path/to/helper > /proc/sys/kernel/hotplug # will use default UDEV_MONITOR_DIR
OR
echo "/full/path/to/helper <dir>" > /proc/sys/kernel/hotplug # change <dir> to your UDEV_MONITOR_DIR
```
2. run application which uses hotplugging (e.g xorg-server)
3. unplug and plug something to test working capacity
That's all! If you realized that this doesn't work for you,
you can always open an issue and describe your bug.
TODO
----
---
Then you can run an application that uses hotplugging like `xorg-server` to see if it's working by unplugging and plugging something back. If you face any problems while trying out any of these methods, please create an issue.
## TODO
* [x] speed up performance
* [x] extend devices support
* [x] extend device support
* [x] implement hotplugging support
Donate
------
## Donate
You can send a donation to `BTC: 1BwrcsgtWZeLVvNeEQSg4A28a3yrGN3FpK` if you like this project.
You can donate if you like this project
BTC: 1BwrcsgtWZeLVvNeEQSg4A28a3yrGN3FpK
Thank you very much !
Thank you very much!