systemd/src/udev/udev-builtin-kmod.c

/*
 * load kernel modules
 *
 * Copyright (C) 2011 Kay Sievers <kay.sievers@vrfy.org>
 * Copyright (C) 2011 ProFUSION embedded systems
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <libkmod.h>

#include "udev.h"

static struct kmod_ctx *ctx;

static int load_module(struct udev *udev, const char *alias)
{
        struct kmod_list *list = NULL;
        struct kmod_list *l;
        int err;

        err = kmod_module_new_from_lookup(ctx, alias, &list);
        if (err < 0)
                return err;

        if (list == NULL)
                log_debug("no module matches '%s'\n", alias);

        kmod_list_foreach(l, list) {
                struct kmod_module *mod = kmod_module_get_module(l);

                err = kmod_module_probe_insert_module(mod, KMOD_PROBE_APPLY_BLACKLIST, NULL, NULL, NULL, NULL);
                if (err == KMOD_PROBE_APPLY_BLACKLIST)
                        log_debug("module '%s' is blacklisted\n", kmod_module_get_name(mod));
                else if (err == 0)
                        log_debug("inserted '%s'\n", kmod_module_get_name(mod));
                else
                        log_debug("failed to insert '%s'\n", kmod_module_get_name(mod));

                kmod_module_unref(mod);
        }

        kmod_module_unref_list(list);
        return err;
}

static void udev_kmod_log(void *data, int priority, const char *file, int line,
                          const char *fn, const char *format, va_list args)
{
        udev_main_log(data, priority, file, line, fn, format, args);
}

/* needs to re-instantiate the context after a reload */
static int builtin_kmod(struct udev_device *dev, int argc, char *argv[], bool test)
{
        struct udev *udev = udev_device_get_udev(dev);
        int i;

        if (!ctx) {
                ctx = kmod_new(NULL, NULL);
                if (!ctx)
                        return -ENOMEM;

                log_debug("load module index\n");
                kmod_set_log_fn(ctx, udev_kmod_log, udev);
                kmod_load_resources(ctx);
        }

        if (argc < 3 || strcmp(argv[1], "load")) {
                log_error("expect: %s load <module>\n", argv[0]);
                return EXIT_FAILURE;
        }

        for (i = 2; argv[i]; i++) {
                log_debug("execute '%s' '%s'\n", argv[1], argv[i]);
                load_module(udev, argv[i]);
        }

        return EXIT_SUCCESS;
}

/* called at udev startup */
static int builtin_kmod_init(struct udev *udev)
{
        if (ctx)
                return 0;

        ctx = kmod_new(NULL, NULL);
        if (!ctx)
                return -ENOMEM;

        log_debug("load module index\n");
        kmod_set_log_fn(ctx, udev_kmod_log, udev);
        kmod_load_resources(ctx);
        return 0;
}

/* called on udev shutdown and reload request */
static void builtin_kmod_exit(struct udev *udev)
{
        log_debug("unload module index\n");
        ctx = kmod_unref(ctx);
}

/* called every couple of seconds during event activity; 'true' if config has changed */
static bool builtin_kmod_validate(struct udev *udev)
{
        log_debug("validate module index\n");
        if (kmod_validate_resources(ctx) != KMOD_RESOURCES_OK)
                return true;
        return false;
}

const struct udev_builtin udev_builtin_kmod = {
        .name = "kmod",
        .cmd = builtin_kmod,
        .init = builtin_kmod_init,
        .exit = builtin_kmod_exit,
        .validate = builtin_kmod_validate,
        .help = "kernel module loader",
        .run_once = false,
};