rfkill: add new rfkill tool to save/restore rfkill state across reboots

This works analogous to the existing backlight and random seed services

src/rfkill/Makefile

@@ -0,0 +1 @@
+../Makefile

src/rfkill/rfkill.c

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+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include "util.h"
+#include "mkdir.h"
+#include "fileio.h"
+#include "libudev.h"
+#include "udev-util.h"
+
+int main(int argc, char *argv[]) {
+        _cleanup_udev_unref_ struct udev *udev = NULL;
+        _cleanup_udev_device_unref_ struct udev_device *device = NULL;
+        _cleanup_free_ char *saved = NULL, *ss = NULL, *escaped_name = NULL;
+        const char *sysname, *name;
+        int r;
+
+        if (argc != 3) {
+                log_error("This program requires two arguments.");
+                return EXIT_FAILURE;
+        }
+
+        log_set_target(LOG_TARGET_AUTO);
+        log_parse_environment();
+        log_open();
+
+        umask(0022);
+
+        r = mkdir_p("/var/lib/systemd/rfkill", 0755);
+        if (r < 0) {
+                log_error("Failed to create rfkill directory: %s", strerror(-r));
+                return EXIT_FAILURE;
+        }
+
+        udev = udev_new();
+        if (!udev) {
+                log_oom();
+                return EXIT_FAILURE;
+        }
+
+        sysname = strchr(argv[2], ':');
+        if (!sysname) {
+                log_error("Requires pair of subsystem and sysname for specifying rfkill device.");
+                return EXIT_FAILURE;
+        }
+
+        ss = strndup(argv[2], sysname - argv[2]);
+        if (!ss) {
+                log_oom();
+                return EXIT_FAILURE;
+        }
+
+        sysname++;
+
+        if (!streq(ss, "rfkill")) {
+                log_error("Not a rfkill device: '%s:%s'", ss, sysname);
+                return EXIT_FAILURE;
+        }
+
+        errno = 0;
+        device = udev_device_new_from_subsystem_sysname(udev, ss, sysname);
+        if (!device) {
+                if (errno != 0)
+                        log_error("Failed to get rfkill device '%s:%s': %m", ss, sysname);
+                else
+                        log_oom();
+
+                return EXIT_FAILURE;
+        }
+
+        name = udev_device_get_sysattr_value(device, "name");
+        if (!name) {
+                log_error("rfkill device has no name?");
+                return EXIT_FAILURE;
+        }
+
+        escaped_name = cescape(name);
+        if (!escaped_name) {
+                log_oom();
+                return EXIT_FAILURE;
+        }
+
+        saved = strjoin("/var/lib/systemd/rfkill/", escaped_name, NULL);
+        if (!saved) {
+                log_oom();
+                return EXIT_FAILURE;
+        }
+
+        if (streq(argv[1], "load")) {
+                _cleanup_free_ char *value = NULL;
+
+                r = read_one_line_file(saved, &value);
+                if (r < 0) {
+
+                        if (r == -ENOENT)
+                                return EXIT_SUCCESS;
+
+                        log_error("Failed to read %s: %s", saved, strerror(-r));
+                        return EXIT_FAILURE;
+                }
+
+                r = udev_device_set_sysattr_value(device, "soft", value);
+                if (r < 0) {
+                        log_error("Failed to write system attribute: %s", strerror(-r));
+                        return EXIT_FAILURE;
+                }
+
+        } else if (streq(argv[1], "save")) {
+                const char *value;
+
+                value = udev_device_get_sysattr_value(device, "soft");
+                if (!value) {
+                        log_error("Failed to read system attribute: %s", strerror(-r));
+                        return EXIT_FAILURE;
+                }
+
+                r = write_string_file(saved, value);
+                if (r < 0) {
+                        log_error("Failed to write %s: %s", saved, strerror(-r));
+                        return EXIT_FAILURE;
+                }
+
+        } else {
+                log_error("Unknown verb %s.", argv[1]);
+                return EXIT_FAILURE;
+        }
+
+        return EXIT_SUCCESS;
+}