Drop mdevd plugin, not needed since notify:s6 support was added

For an example how to set it up, see the finit-skel repository:

https://github.com/troglobit/finit-skel/blob/main/skel/etc/finit.d/available/mdevd.conf

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

configure.ac

@@ -86,7 +86,6 @@ AC_ARG_ENABLE(all_plugins,
 	enable_all_plugins=$enableval, enable_all_plugins=auto)
 AC_PLUGIN([alsa-utils],    [no],  [Save and restore ALSA sound settings using alsactl])
 AC_PLUGIN([dbus],          [no],  [Setup and start system message bus, D-Bus])
-AC_PLUGIN([mdevd],         [no],  [Setup and start system hotplug helper mdevd])
 AC_PLUGIN([modules-load],  [no],  [Scans /etc/modules-load.d for modules to load])
 AC_PLUGIN([modprobe],      [yes], [Coldplug modules using modalias magic])
 AC_PLUGIN([resolvconf],    [no],  [Setup necessary files for resolvconf])

doc/config.md

@@ -551,7 +551,7 @@ option:
     (must be >3) on then command line, Finit provides the following
     syntax (`%n` is replaced by Finit with then descriptor number):
 
-        service notify:s6 mdevd -C -O 4 -D %n
+        service [S12345789] notify:s6 mdevd -O 4 -D %n
 
 [sd_notify()]: https://www.freedesktop.org/software/systemd/man/sd_notify.html
 [s6 expect]:   https://skarnet.org/software/s6/notifywhenup.html
@@ -563,6 +563,16 @@ then service's ready condition which other services can depend on:
     $ initctl -v cond get service/mdevd/ready
     on
 
+This can be used to synchronize the start of another run/task/service:
+
+    task [S] <service/mdevd/ready> @root:root mdevd-coldplug
+
+Finit waits for `mdevd` to notify it, before starting `mdevd-coldplug`.
+Notice how both start in runlevel S, and the coldplug task only runs in
+S.  When the system moves to runlevel 2 (the default), coldplug is no
+longer part of the running configuration (`initctl show`), this is to
+ensure that coldplug is not called more than once.
+
 >  For a detailed description of conditions, and how to debug them,
 >  see the [Finit Conditions](conditions.md) document.
 

doc/plugins.md

@@ -52,9 +52,9 @@ For your convenience a set of *optional* plugins are available:
 
 * *hotplug.so*: Setup and start either udev or mdev hotplug daemon, if
   available.  Enabled by default.
-
+  
-* *mdevd.so*: Set up and start mdevd (mdev replacement).  Enabling this
+  > See the [Services](config.md#services) section in the configuration
-  also changes how `hotplug.so` plugin operates.  _Optional plugin._
+  > guide for an example how to run `mdevd`, alternative to plain mdev.
 
 * *rtc.so*: Restore and save system clock from/to RTC on boot/halt.
   Enabled by default.

plugins/Makefile.am

@@ -21,10 +21,6 @@ if BUILD_HOTPLUG_PLUGIN
 libplug_la_SOURCES += hotplug.c
 endif
 
-if BUILD_MDEVD_PLUGIN
-libplug_la_SOURCES += mdevd.c
-endif
-
 if BUILD_MODULES_LOAD_PLUGIN
 libplug_la_SOURCES += modules-load.c
 endif
@@ -76,10 +72,6 @@ if BUILD_HOTPLUG_PLUGIN
 pkglib_LTLIBRARIES += hotplug.la
 endif
 
-if BUILD_MDEVD_PLUGIN
-pkglib_LTLIBRARIES += mdevd.la
-endif
-
 if BUILD_MODULES_LOAD_PLUGIN
 pkglib_LTLIBRARIES += modules-load.la
 endif

plugins/hotplug.c

@@ -39,21 +39,6 @@ static void setup(void *arg)
 		return;
 	}
 
-	/*
-	 * If the mdevd plugin is enabled and loaded we assume this
-	 * system is mdevd based, skipping below udev/mdev checks.
-	 */
-	if (plugin_find("mdevd")) {
-		path = which("mdevd-coldplug");
-		if (path) {
-			snprintf(cmd, sizeof(cmd), "cgroup.system [S] <service/mdevd/ready> log %s "
-				 " -- Populating device tree", path);
-			service_register(SVC_TYPE_RUN, cmd, global_rlimit, NULL);
-			free(path);
-		}
-		return;
-	}
-
 	/*
 	 * Populate /dev and prepare for runtime events from kernel.
 	 * Prefer udev if mdev is also available on the system.
@@ -105,13 +90,12 @@ static void setup(void *arg)
 	}
 }
 
-/* mdevd optional, if installed & loaded changes behavior of setup() */
 static plugin_t plugin = {
 	.name = __FILE__,
 	.hook[HOOK_BASEFS_UP] = {
 		.cb  = setup
 	},
-	.depends = { "bootmisc", "mdevd", "modprobe" },
+	.depends = { "bootmisc", "modprobe" },
 };
 
 PLUGIN_INIT(plugin_init)

plugins/mdevd.c

@@ -1,123 +0,0 @@
-/* Setup and start system hotplug helper mdevd
- *
- * Portions Copyright (c) 2012-2022  Joachim Wiberg <troglobit@gmail.com>
- * Portions Copyright (c) 2022 Andy Savage <andy@savage.hk>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- * THE SOFTWARE.
- */
-
-#include <sys/types.h>
-#ifdef _LIBITE_LITE
-# include <libite/lite.h>
-#else
-# include <lite/lite.h>
-#endif
-
-#include "finit.h"
-#include "config.h"
-#include "helpers.h"
-#include "plugin.h"
-#include "service.h"
-#include "conf.h"
-
-#define MDEVD_DAEMON "mdevd"
-/* Rebroadcast events onto nlgroup 4 */
-#define MDEVD_ARGS   "-C -O 4 -D %n"
-#define MDEVD_DESC   "MDEVD Extended Hotplug Daemon"
-
-#ifndef MDEVD_DAEMONUSER
-#define MDEVD_DAEMONUSER "root"
-#endif
-
-#ifndef MDEVD_DAEMONGROUP
-#define MDEVD_DAEMONGROUP "root"
-#endif
-
-#ifndef MDEVD_DAEMONPIDFILE
-#define MDEVD_DAEMONPIDFILE "/var/run/mdevd.pid"
-#endif
-
-static void setup(void *arg)
-{
-	char line[256];
-	mode_t prev;
-	char *cmd;
-	FILE *fp;
-
-	if (rescue) {
-		dbg("Skipping %s plugin in rescue mode.", __FILE__);
-		return;
-	}
-
-	cmd = which(MDEVD_DAEMON);
-	if (!cmd) {
-		dbg("Skipping plugin, %s is not installed.", MDEVD_DAEMON);
-		return;
-	}
-
-	prev =umask(0);
-
-	/* Clean up from any previous pre-bootstrap run */
-	remove(MDEVD_DAEMONPIDFILE);
-
-	/* Set hotplug helper */
-	fp = fopen("/proc/sys/kernel/hotplug", "w");
-	if (fp) {
-		fputc('\n', fp);
-		fclose(fp);
-	}
-
-	/* Register service with Finit */
-	if (debug)
-		snprintf(line, sizeof(line), "[S12345789] cgroup.system notify:s6 pid:!%s @%s:%s %s -v3 %s -- %s",
-			 MDEVD_DAEMONPIDFILE, MDEVD_DAEMONUSER, MDEVD_DAEMONGROUP, cmd, MDEVD_ARGS, MDEVD_DESC);
-	else
-		snprintf(line, sizeof(line), "[S12345789] cgroup.system notify:s6 pid:!%s @%s:%s %s %s -- %s",
-			 MDEVD_DAEMONPIDFILE, MDEVD_DAEMONUSER, MDEVD_DAEMONGROUP, cmd, MDEVD_ARGS, MDEVD_DESC);
-	if (service_register(SVC_TYPE_SERVICE, line, global_rlimit, NULL))
-		err(1, "Failed registering %s", MDEVD_DAEMON);
-	free(cmd);
-
-	umask(prev);
-}
-
-static plugin_t plugin = {
-	.name = __FILE__,
-	.hook[HOOK_BASEFS_UP] = {
-		.cb  = setup
-	},
-	.depends = { "bootmisc", },
-};
-
-PLUGIN_INIT(plugin_init)
-{
-	plugin_register(&plugin);
-}
-
-PLUGIN_EXIT(plugin_exit)
-{
-	plugin_unregister(&plugin);
-}
-
-/**
- * Local Variables:
- *  indent-tabs-mode: t
- *  c-file-style: "linux"
- * End:
- */