procd is the new OpenWrt process management daemon written in C. It keeps track of processes started from init scripts (via ubus calls), and can suppress redundant service start/restart requests when the config/environment has not changed.
procd has replaced … , e.g.
hotplug2, a dynamic device management subsystem for embedded systems. Hotplug2 is a trivial replacement of some of the UDev functionality in a tiny pack, intended for Linux early userspace: Init RAM FS and InitRD.
procd is intended to stay compatible with the existing format of
/etc/config/; exceptions …
see use case http://wiki.openwrt.org/doc/howto/hardware.button
One thing that
procd does much better then …
It boils down to the fact that the current … are rather constrained and inflexible:
procd will be able to …
- and of course all that without adding unnecessary bloat. AFAIK there are no alternatives to procd.
Whereas desktop distributions use glib and dbus (and udev) OpenWrt uses libubox and ubus (and hotplug2). This provides some pretty awesome functionality without requiring huge libraries with huge dependencies (*cough* glib).
|Typical main memory size||128 MiB to 16 GiB (or more)||32 MiB to 512 MiB1)|| min 92 MiB for Android 2.1 |
min 340 MiB for Android 4.0
|Supported instruction sets||almost anything||almost anything||x86, 86-64, ARM, MIPS32|
|non-volatile storage space||100 MiB||8 MiB2)|| 150MiB for Android 2.1|
512MiB for Android 4.0
|FOSS and binary drivers||FOSS drivers: e.g. 802.11; Iaccess||Android binary drivers|
|C standard library||glibc||uClibc||bionic||glibc + libhybris||eglibc 2.15|
| ||busybox-initd|| ||Android init-fork||
|rsyslog / syslog-ng||busybox-klogd, busybox-syslogd|
|network configuration||NetworkManager + GUI|| || ConnectivityManager|
(not ConnMan = ConnectionManager!)
| GLib |
(GObject, Glib, GModule, GThread, GIO)
|Package management system|| dpkg/APT|
libubox(~ 12KiB) is a general purpose library which provides things like an event loop, binary blob message formatting and handling, the Linux linked list implementation, and some JSON helpers. The functions in
libuboxare used to write the other software in LuCI2
ubus(~ 13KiB) is an RPC daemon similar to D-Bus but with a much friendlier C API
dbus is bloated, its C API is very annoying to use and requires writing large amounts of boilerplate code. In fact, the pure C API is so annoying that its own API documentation states: "If you use this low-level API directly, you're signing up for some pain."
ubus is tiny and has the advantage of being easy to use from regular C code, as well as automatically making all exported API functionality also available to shell scripts with no extra effort.
"Of course, NetworkManager should be renamed to
"unetwork", dbus to
"ubus", PulseAudio to
"usound", and X.Org-Server/Wayland-Compositor to
"udisplay"; and then indescribable happiness would come down to all people of this world." – Lennart Poettering
Package history is available at: