plugins: new sys condition event monitor (wip)

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

plugins/Makefile.am

@@ -7,7 +7,7 @@ AM_CPPFLAGS        += $(lite_CFLAGS)
 
 if STATIC
 noinst_LTLIBRARIES  = libplug.la
-libplug_la_SOURCES  = bootmisc.c modprobe.c rtc.c pidfile.c procps.c tty.c urandom.c usr.c
+libplug_la_SOURCES  = bootmisc.c modprobe.c rtc.c pidfile.c procps.c sys.c tty.c urandom.c usr.c
 
 if BUILD_ALSA_UTILS_PLUGIN
 libplug_la_SOURCES += alsa-utils.c
@@ -34,7 +34,7 @@ libplug_la_SOURCES += resolvconf.c
 endif
 
 else
-pkglib_LTLIBRARIES  = bootmisc.la modprobe.la rtc.la pidfile.la procps.la tty.la urandom.la usr.la
+pkglib_LTLIBRARIES  = bootmisc.la modprobe.la rtc.la pidfile.la procps.la sys.la tty.la urandom.la usr.la
 
 if BUILD_ALSA_UTILS_PLUGIN
 pkglib_LTLIBRARIES += alsa-utils.la

plugins/sys.c

@@ -0,0 +1,196 @@
+/* System condtion event monitor for the Finit condition engine
+ *
+ * Copyright (c) 2021  Joachim Wiberg <troglobit@gmail.com>
+ *
+ * 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 <dirent.h>
+#include <fnmatch.h>
+#include <glob.h>
+#include <limits.h>
+#include <paths.h>
+
+#include "finit.h"
+#include "cond.h"
+#include "pid.h"
+#include "plugin.h"
+#include "iwatch.h"
+
+#define _PATH_SYSFS_PWR  "/sys/class/power_supply"
+
+static struct iwatch iw_sys;
+static int num_ac;
+
+static void check_online(char *path, int clear)
+{
+	char cond[MAX_COND_LEN] = COND_SYS;
+	int val;
+
+	if (fngetint(path, &val))
+		return;
+
+	strlcat(cond, "pwr/ac", sizeof(cond));
+	if (val)
+		cond_set_oneshot(cond);
+	else if (clear)
+		cond_clear(cond);
+}
+
+static void sys_callback(void *arg, int fd, int events)
+{
+	static char ev_buf[8 *(sizeof(struct inotify_event) + NAME_MAX + 1) + 1];
+	struct inotify_event *ev;
+	ssize_t sz;
+	size_t off;
+
+	sz = read(fd, ev_buf, sizeof(ev_buf) - 1);
+	if (sz <= 0) {
+		_pe("invalid inotify event");
+		return;
+	}
+	ev_buf[sz] = 0;
+
+	for (off = 0; off < (size_t)sz; off += sizeof(*ev) + ev->len) {
+		struct iwatch_path *iwp;
+
+		if (off + sizeof(*ev) > (size_t)sz)
+			break;
+
+		ev = (struct inotify_event *)&ev_buf[off];
+		if (off + sizeof(*ev) + ev->len > (size_t)sz)
+			break;
+
+		_d("name %s, event: 0x%08x", ev->name, ev->mask);
+		if (!ev->mask)
+			continue;
+
+		/* Find base path for this event */
+		iwp = iwatch_find_by_wd(&iw_sys, ev->wd);
+		if (!iwp)
+			continue;
+
+		check_online(iwp->path, 1);
+	}
+}
+
+static int is_ac(char *path, size_t len)
+{
+	char type[32] = { 0 };
+	char *types[] = {
+		"Mains",
+		"USB",
+		"BrickID",
+		"Wireless",
+		NULL
+	};
+	FILE *fp;
+	int i;
+
+	strlcat(path, "/type", len);
+	fp = fopen(path, "r");
+	if (!fp)
+		return 0;
+
+	if (!fgets(type, sizeof(type), fp)) {
+		fclose(fp);
+		return 0;
+	}
+	fclose(fp);
+
+	for (i = 0; types[i]; i++) {
+		if (!strncmp(type, types[i], strlen(types[i])))
+			return 1;
+	}
+
+	return 0;
+}
+
+static void sys_init(void *arg)
+{
+	struct dirent **d = NULL;
+	char path[384];
+	int i, n;
+
+	if (mkpath(pid_runpath(_PATH_CONDSYS, path, sizeof(path)), 0755) && errno != EEXIST) {
+		_pe("Failed creating %s condition directory, %s", COND_SYS, _PATH_CONDSYS);
+		return;
+	}
+
+	n = scandir(_PATH_SYSFS_PWR, &d, NULL, alphasort);
+	if (n <= 0) {
+		iwatch_exit(&iw_sys);
+		return;
+	}
+		
+	for (i = 0; i < n; i++) {
+		char *nm = d[i]->d_name;
+
+		snprintf(path, sizeof(path), "%s/%s", _PATH_SYSFS_PWR, nm);
+		if (is_ac(path, sizeof(path))) {
+			num_ac++;
+
+			snprintf(path, sizeof(path), "%s/%s/online", _PATH_SYSFS_PWR, nm);
+			check_online(path, 0);
+
+			if (iwatch_add(&iw_sys, path, 0))
+				_pe("Failed setting up pwr monitor for %s", path);
+		}
+		free(d[i]);
+	}
+	free(d);
+}
+
+static plugin_t plugin = {
+	.name = __FILE__,
+	.hook[HOOK_BASEFS_UP]  = { .cb = sys_init },
+};
+
+PLUGIN_INIT(plugin_init)
+{
+	int fd;
+
+	if (!fisdir(_PATH_SYSFS_PWR)) {
+		_w("System does not have %s, disabling AC power monitor.", _PATH_SYSFS_PWR);
+		return;
+	}
+
+	fd = iwatch_init(&iw_sys);
+	if (fd < 0)
+		return;
+
+	plugin.io.fd = fd;
+	plugin.io.cb = sys_callback;
+	plugin.io.flags = PLUGIN_IO_READ;
+
+	plugin_register(&plugin);
+}
+
+PLUGIN_EXIT(plugin_exit)
+{
+	iwatch_exit(&iw_sys);
+	plugin_unregister(&plugin);
+}
+
+/**
+ * Local Variables:
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */

src/cond-w.c

@@ -163,7 +163,7 @@ int cond_set_path(const char *path, enum cond_state next)
 	return next != prev;
 }
 
-/* Should only be used by cond_set*(), cond_clear(), and usr plugin! */
+/* Should only be used by cond_set*(), cond_clear(), and usr/sys plugins! */
 void cond_update(const char *name)
 {
 	svc_t *svc, *iter = NULL;

src/cond.h

@@ -5,12 +5,14 @@
 #include <svc.h>
 
 #define COND_BASE      "finit/cond"
-#define COND_USR       "usr/"
 #define COND_PID       "pid/"
+#define COND_SYS       "sys/"
+#define COND_USR       "usr/"
 
 #define _PATH_COND     _PATH_VARRUN COND_BASE "/"
-#define _PATH_CONDUSR  _PATH_COND   COND_USR
 #define _PATH_CONDPID  _PATH_COND   COND_PID
+#define _PATH_CONDSYS  _PATH_COND   COND_SYS
+#define _PATH_CONDUSR  _PATH_COND   COND_USR
 #define _PATH_RECONF   _PATH_COND   "reconf"
 
 typedef enum cond_state {