diff options
| author | Laurent Bercot <ska-skaware@skarnet.org> | 2018-01-14 17:54:42 +0000 |
|---|---|---|
| committer | Laurent Bercot <ska-skaware@skarnet.org> | 2018-01-14 17:54:42 +0000 |
| commit | 4984158b95c5a0c3922cd34940c393652d080f99 (patch) | |
| tree | bd110462519e041679dc0332088b43132214fe45 /doc | |
| parent | c5e7afbd8d62f3217687f21c0691a02797dc0df5 (diff) | |
| download | mdevd-4984158b95c5a0c3922cd34940c393652d080f99.tar.xz | |
New mdevd model, prepare for 0.1.0.0
- mdevd-netlink removed
- mdevd listens to the netlink itself
- mdevd-coldplug writes nothing to stdout, but triggers the kernel to create uevents
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/index.html | 5 | ||||
| -rw-r--r-- | doc/mdevd-coldplug.html | 25 | ||||
| -rw-r--r-- | doc/mdevd-netlink.html | 124 | ||||
| -rw-r--r-- | doc/mdevd.html | 44 | ||||
| -rw-r--r-- | doc/upgrade.html | 11 |
5 files changed, 42 insertions, 167 deletions
diff --git a/doc/index.html b/doc/index.html index c11b508..19a43a4 100644 --- a/doc/index.html +++ b/doc/index.html @@ -53,7 +53,7 @@ entirely compatible with advanced mdev usage such as The Linux kernel must be 2.6.10 or later. </li> <li> GNU make, version 3.81 or later </li> <li> <a href="//skarnet.org/software/skalibs/">skalibs</a> version -2.6.0.2 or later. It's a build-time requirement. It's also a run-time +2.6.3.0 or later. It's a build-time requirement. It's also a run-time requirement if you link against the shared version of the skalibs library. </li> </ul> @@ -69,7 +69,7 @@ library. </li> <ul> <li> The current released version of mdevd is -<a href="mdevd-0.0.1.0.tar.gz">0.0.1.0</a>. </li> +<a href="mdevd-0.1.0.0.tar.gz">0.1.0.0</a>. </li> <li> Alternatively, you can checkout a copy of the <a href="//git.skarnet.org/cgi-bin/cgit.cgi/mdevd/">mdevd git repository</a>: @@ -100,7 +100,6 @@ the previous versions of mdevd and the current one. </li> <ul> <li><a href="mdevd.html">The <tt>mdevd</tt> program</a></li> -<li><a href="mdevd-netlink.html">The <tt>mdevd-netlink</tt> program</a></li> <li><a href="mdevd-coldplug.html">The <tt>mdevd-coldplug</tt> program</a></li> </ul> diff --git a/doc/mdevd-coldplug.html b/doc/mdevd-coldplug.html index fbbb5aa..027c849 100644 --- a/doc/mdevd-coldplug.html +++ b/doc/mdevd-coldplug.html @@ -21,8 +21,8 @@ <p> <tt>mdevd-coldplug</tt> performs a <em>coldplug</em>: it scans <tt>/sys</tt> for all registered devices a uevent manager would -want to perform actions on, and generates uevents for all these -devices. +want to perform actions on, and tells the kernel to generate uevents +for all these devices. </p> <h2> Interface </h2> @@ -33,17 +33,13 @@ devices. <ul> <li> mdevd-coldplug scans <tt>/sys</tt> for devices. </li> - <li> For every suitable device it finds, it generates a -uevent and writes it to its stdout, using the same format -as <a href="mdevd-netlink.html">mdevd-netlink</a>. </li> - <li> It exits when it has finished scanning. </li> + <li> For every suitable device it finds, it tells the kernel +to generate an event. If a device manager such as +as <a href="mdevd.html">mdevd</a> is listening to the netlink +at this point, it will pick up the series of events. </li> + <li> mdevd-coldplug exits when it has finished scanning. </li> </ul> -<p> - This implies that the <tt>mdevd-coldplug | mdevd</tt> command line -will function as a coldplug manager, just like <tt>mdev -s</tt>. -</p> - <h2> Options </h2> <ul> @@ -62,12 +58,7 @@ pseudo-filesystem is mounted on <em>slashsys</em>. Default is <tt>/sys</tt>. </l <ul> <li> mdevd-coldplug is a short-lived program, just like -<tt>mdev -s</tt>. </li> - <li> Unlike <tt>mdev -s</tt>, however, mdevd-coldplug does -not act on the uevents it generates. It simply prints them. -This allows for easy debugging. </li> - <li> To act on the uevents, simply pipe the output of -<tt>mdevd-coldplug</tt> into <a href="mdevd.html">mdevd</a>. </li> +<tt>mdev -s</tt> or <tt>udevadm trigger</tt>. </li> </ul> </body> diff --git a/doc/mdevd-netlink.html b/doc/mdevd-netlink.html deleted file mode 100644 index d0aa054..0000000 --- a/doc/mdevd-netlink.html +++ /dev/null @@ -1,124 +0,0 @@ -<html> - <head> - <meta name="viewport" content="width=device-width, initial-scale=1.0" /> - <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> - <meta http-equiv="Content-Language" content="en" /> - <title>mdevd: the mdevd-netlink program</title> - <meta name="Description" content="mdevd: the mdevd-netlink program" /> - <meta name="Keywords" content="mdevd linux administration root utilities devd mdev udev s6-uevent-listener uevent netlink" /> - <!-- <link rel="stylesheet" type="text/css" href="//skarnet.org/default.css" /> --> - </head> -<body> - -<p> -<a href="index.html">mdevd</a><br /> -<a href="//skarnet.org/software/">Software</a><br /> -<a href="//skarnet.org/">skarnet.org</a> -</p> - -<h1> The <tt>mdevd-netlink</tt> program </h1> - -<p> -<tt>mdevd-netlink</tt> listens to the netlink interface for uevents -(also called "hotplug" or "udev" events), and writes those uevents to -its standard output, using a simple format. -</p> - -<p> -<a href="mdevd.html">mdevd</a> expects uevents in the same -format mdevd-netlink writes them. So the -<tt>mdevd-netlink | mdevd</tt> command line will function as -a daemon reading uevents from the netlink and handling them. -</p> - -<h2> Interface </h2> - -<pre> - mdevd-netlink [ -d notif ] [ -v <em>verbosity</em> ] [ -b kbufsz ] -</pre> - -<ul> - <li> mdevd-netlink binds to the netlink interface and listens for -hotplug events, as the <em>udevd</em> program does. </li> - <li> It writes event information to its stdout. The output contains -null characters, so a terminal will not display them correctly. To -properly use mdevd-netlink, it should be piped into a handler -program such as <a href="mdevd.html">mdevd</a>. </li> - <li> mdevd-netlink is a long-lived program. -When it receives a SIGTERM, it stops listening to hotplug events; -it will exit as soon as it has flushed its event queue to stdout. </li> -</ul> - -<h2> Options </h2> - -<ul> - <li> <tt>-d</tt> <em>notif</em> : when ready (actually -listening to the netlink), write a newline to file descriptor <em>notif</em> -then close it. This allows mdevd-netlink to use the -<a href="//skarnet.org/software/s6/notifywhenup.html">s6 mechanism to -notify readiness</a>. <em>notif</em> cannot be lesser than 3. If this -option is not given, no readiness notification is sent. </li> - <li> <tt>-v</tt> <em>verbosity</em> : be more or less verbose. -Default verbosity is 1. 0 will only print fatal error messages, 3 will -print warnings every time the netlink interface sends something -unexpected. </li> - <li> <tt>-b</tt> <em>kbufsz</em> : try and reserve a kernel buffer of -<em>kbufsz</em> bytes for the netlink queue. Too large a buffer wastes kernel memory; -too small a buffer risks losing events. The default is 65536 (which is on -the large side). </li> -</ul> - -<h2> Protocol </h2> - -<ul> - <li> An event is a series of null-terminated strings as they are sent by -the kernel to the netlink; mdevd-netlink adds a final empty string -(i.e. an additional null character) to mark the end of the series. </li> - <li> The first string is a short description of the event; it normally -contains the string "@/". Other strings after the first are of the form -"VARIABLE=value", and describe the environment which a hotplug helper -for the event (registered in <tt>/proc/sys/kernel/hotplug</tt>) would be -spawned with. </li> - <li> Example (newlines added for clarity): <pre> -add@/class/input/input9/mouse2\0 -ACTION=add\0 -DEVPATH=/class/input/input9/mouse2\0 -SUBSYSTEM=input\0 -SEQNUM=106\0 -PHYSDEVPATH=/devices/pci0000:00/0000:00:1d.1/usb2/22/22:1.0 -PHYSDEVBUS=usb\0 -PHYSDEVDRIVER=usbhid\0 -MAJOR=13\0 -MINOR=34\0 -\0 </pre> </li> -</ul> - -<h2> Notes </h2> - -<ul> - <li> mdevd-netlink is a daemon; it should be run under a proper supervision system such -as <a href="//skarnet.org/software/s6/">s6</a>. </li> -<li> If you are running mdevd-netlink, the program you pipe its -output into should be the only program handling uevents; that means -that <tt>/proc/sys/kernel/hotplug</tt> should be empty. </li> -<li> The <tt>mdevd-netlink | mdevd</tt> command line is a quick -way of running a uevent manager, but there are ways to improve it: - <ul> - <li> Using the -<a href="//skarnet.org/software/execline/">execline</a> scripting -language, the <tt>pipeline { mdevd-netlink } mdevd</tt> command -line will avoid leaving a shell around. </li> - <li> The best way to use mdevd-netlink and mdevd is with a -supervision system: -under <a href="//skarnet.org/software/s6/">s6</a> or -<a href="//skarnet.org/software/s6-rc/">s6-rc</a>, write a service -pipeline where <tt>mdevd-netlink</tt> is a producer and -<tt>mdevd</tt> is a consumer. This setup has the advantage, among -others, that you can restart the netlink listener and the event handler -separately. The <tt>examples/</tt> subdirectory of the mdevd -package contains example configurations for such a setup. </li> - </ul> </li> -</ul> - -</body> -</html> diff --git a/doc/mdevd.html b/doc/mdevd.html index 14d2867..0ea61bb 100644 --- a/doc/mdevd.html +++ b/doc/mdevd.html @@ -19,8 +19,8 @@ <h1> The <tt>mdevd</tt> program </h1> <p> -<tt>mdevd</tt> is a uevent manager. It reads a series of -uevents on its stdin; for every uevent it reads, it performs +<tt>mdevd</tt> is a uevent manager. It connects to the netlink and reads +a series of uevents; for every uevent it reads, it performs actions according to its configuration file. Actions can be inserting a kernel module, creating or modifying device entries in <tt>/dev</tt>, etc. @@ -36,35 +36,29 @@ The differences between mdevd and mdev are: <ul> <li> mdev needs to be registered as a hotplug manager and the kernel spawns an instance of mdev per uevent; for every uevent, -mdev has to parse its configuration file. By contrast, there -is only one instance of mdevd, reading a series of uevents and +mdev has to parse its configuration file. By contrast, mdevd is +a daemon: it's long-lived, and there is only one instance, +reading a series of uevents and performing actions without forking; the configuration file is read and parsed only once. </li> - <li> mdevd reads uevents on its stdin. It is not suitable as -a hotplug manager, and it does not connect to the netlink itself -either. It is meant to be used in conjunction with -<a href="mdevd-netlink.html">mdevd-netlink</a>, which reads -uevents from the netlink, or with -<a href="mdevd-coldplug.html">mdevd-coldplug</a>, which generates -coldplug uevents. </li> </ul> <h2> Interface </h2> <pre> - mdevd [ -v <em>verbosity</em> ] [ -f <em>conffile</em> ] [ -n ] [ -s <em>slashsys</em> ] [ -d <em>slashdev</em> ] [ -F <em>fwbase</em> ] + mdevd [ -v <em>verbosity</em> ] [ -D <em>notif</em> ] [ -b <em>kbufsz</em> ] [ -f <em>conffile</em> ] [ -n ] [ -s <em>slashsys</em> ] [ -d <em>slashdev</em> ] [ -F <em>fwbase</em> ] </pre> <ul> <li> mdevd reads and parses its configuration file <tt>/etc/mdev.conf</tt>. </li> - <li> It then reads its stdin, waiting for uevents. - <li> It exits when the stream of uevents ends. (EOF on stdin.) </li> + <li> It then connects to the netlink and reads from it, waiting for uevents. + <li> It exits 0 on a SIGTERM. </li> </ul> <h2> Exit codes </h2> <ul> - <li> 0: EOF read on standard input </li> + <li> 0: SIGTERM received, clean exit </li> <li> 1: received an invalid event </li> <li> 2: syntax error in the configuration file </li> <li> 100: wrong usage </li> @@ -79,6 +73,7 @@ coldplug uevents. </li> <ul> <li> SIGHUP: re-read the configuration file </li> + <li> SIGTERM: exit as soon as possible </li> </ul> <h2> Options </h2> @@ -87,6 +82,17 @@ coldplug uevents. </li> <li> <tt>-v</tt> <em>verbosity</em> : be more or less verbose. Default verbosity is 1. 0 will only print fatal error messages, 3 or more is seriously verbose debugging. </li> + <li> <tt>-D</tt> <em>notif</em> : when ready +(actually listening to the netlink), +write a newline to file descriptor <em>notif</em> then close it. +This allows mdevd to use the +<a href="//skarnet.org/software/s6/notifywhenup.html">s6 mechanism to notify +readiness</a>. <em>notif</em> cannot be lesser than 3. +If this option is not given, no readiness notification is sent. </li> + <li> <tt>-b</tt> <em>kbufsz</em> : try and reserve a kernel buffer of +<em>kbufsz</em> bytes for the netlink queue. Too large a buffer wastes kernel memory; +too small a buffer risks losing events. The default is 65536 (which is reasonable +for average systems). </li> <li> <tt>-n</tt> : dry run. mdevd will not create or delete device nodes, and it will not spawn commands. Instead, it will print to stdout the actions it would have performed. </li> @@ -121,14 +127,6 @@ nothing else. <h2> Notes </h2> <ul> - <li> Strictly speaking, mdevd is a short-lived program: it has -a normal exit condition, which is when it receives EOF on its stdin. -That allows it to work as a coldplug manager when paired with -<a href="mdevd-coldplug.html">mdevd-coldplug</a>. </li> - <li> However, when paired with <a href="mdevd-netlink.html">mdevd-netlink</a>, -it acts as a daemon, because mdev-netlink normally never exits until -the end of the machine lifetime and never closes its stdout, so -mdevd's stdin never receives EOF. </li> <li> The <tt>examples/</tt> subdirectory of the mdevd package contains examples on how to run mdevd under various init systems / supervisors. </li> </ul> diff --git a/doc/upgrade.html b/doc/upgrade.html index 06c1654..fbbcc00 100644 --- a/doc/upgrade.html +++ b/doc/upgrade.html @@ -18,6 +18,17 @@ <h1> What has changed in mdevd </h1> +<h2> in 0.1.0.0 </h2> + +<ul> + <li> <a href="//skarnet.org/software/skalibs/">skalibs</a> +dependency bumped to 2.6.3.0. </li> + <li> The <tt>mdevd-netlink</tt> program doesn't exist anymore. </li> + <li> <a href="mdevd.html">mdevd</a> now listens to the netlink itself. </li> + <li> <a href="mdevd-coldplug.html">mdevd-coldplug</a> does not print events +to stdout anymore. Instead, it makes the kernel trigger events. </li> +</ul> + <h2> in 0.0.1.0 </h2> <ul> |