kmod/tools/static-nodes.c

/*
 * kmod-static-nodes - manage modules.devname
 *
 * Copyright (C) 2004-2012 Kay Sievers <kay@vrfy.org>
 * Copyright (C) 2011-2013  ProFUSION embedded systems
 * Copyright (C) 2013 Tom Gundersen <teg@jklm.no>
 *
 * 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 <stddef.h>
#include <getopt.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>
#include <sys/utsname.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "libkmod-util.h"

#include "kmod.h"

struct static_nodes_format {
        const char *name;
        int (*write)(FILE *, char[], char[], char, unsigned int, unsigned int);
        const char *description;
};

static const struct static_nodes_format static_nodes_format_human;
static const struct static_nodes_format static_nodes_format_tmpfiles;
static const struct static_nodes_format static_nodes_format_devname;

static const struct static_nodes_format *static_nodes_formats[] = {
        &static_nodes_format_human,
        &static_nodes_format_tmpfiles,
        &static_nodes_format_devname,
};

static const char cmdopts_s[] = "o:f:h";
static const struct option cmdopts[] = {
        { "output", required_argument, 0, 'o'},
        { "format", required_argument, 0, 'f'},
        { "help", no_argument, 0, 'h'},
        { },
};

static int write_human(FILE *out, char modname[], char devname[], char type, unsigned int maj, unsigned int min)
{
        int ret;

        ret = fprintf(out,
                        "Module: %s\n"
                        "\tDevice node: /dev/%s\n"
                        "\t\tType: %s device\n"
                        "\t\tMajor: %u\n"
                        "\t\tMinor: %u\n",
                        modname, devname, (type == 'c') ? "character" : "block", maj, min);
        if (ret >= 0)
                return EXIT_SUCCESS;
        else
                return EXIT_FAILURE;
}

static const struct static_nodes_format static_nodes_format_human = {
	.name = "human",
	.write = write_human,
        .description = "(default) a human readable format. Do not parse.",
};


static int write_tmpfiles(FILE *out, char modname[], char devname[], char type, unsigned int maj, unsigned int min)
{
        int ret;

        ret = fprintf(out, "%c /dev/%s 0600 - - - %u:%u\n", type, devname, maj, min);
        if (ret >= 0)
                return EXIT_SUCCESS;
        else
                return EXIT_FAILURE;
}

static const struct static_nodes_format static_nodes_format_tmpfiles = {
	.name = "tmpfiles",
	.write = write_tmpfiles,
        .description = "the tmpfiles.d(5) format used by systemd-tmpfiles.",
};

static int write_devname(FILE *out, char modname[], char devname[], char type, unsigned int maj, unsigned int min)
{
        int ret;

        ret = fprintf(out, "%s %s %c%u:%u\n", modname, devname, type, maj, min);
        if (ret >= 0)
                return EXIT_SUCCESS;
        else
                return EXIT_FAILURE;
}

static const struct static_nodes_format static_nodes_format_devname = {
	.name = "devname",
	.write = write_devname,
        .description = "the modules.devname format.",
};

static void help(void)
{
        size_t i;

        printf("Usage:\n"
                "\t%s static-nodes [options]\n"
                "\n"
                "kmod static-nodes outputs the static-node information of the currently running kernel.\n"
                "\n"
                "Options:\n"
                "\t-f, --format=FORMAT  use a machine-readable format\n"
                "\t-o, --output=FILE    write output to file\n"
                "\t-h, --help           show this help\n"
                "\n"
                "Formats:\n",
                program_invocation_short_name);

        for (i = 0; i < ARRAY_SIZE(static_nodes_formats); i++) {
                if (static_nodes_formats[i]->description != NULL) {
                        printf("\t%-12s %s\n", static_nodes_formats[i]->name,
                                        static_nodes_formats[i]->description);
                }
        }
}

static int do_static_nodes(int argc, char *argv[])
{
        struct utsname kernel;
        char modules[PATH_MAX];
        FILE *in = NULL, *out = stdout;
        const struct static_nodes_format *format = &static_nodes_format_human;
        char buf[4096];
        int ret = EXIT_SUCCESS;

        for (;;) {
                int c, idx = 0, valid;
                size_t i;

                c = getopt_long(argc, argv, cmdopts_s, cmdopts, &idx);
                if (c == -1) {
                        break;
                }
                switch (c) {
                case 'o':
                        out = fopen(optarg, "we");
                        if (out == NULL) {
                                fprintf(stderr, "Error: could not create %s!\n", optarg);
                                ret = EXIT_FAILURE;
                                goto finish;
                        }
                        break;
                case 'f':
                        valid = 0;

                        for (i = 0; i < ARRAY_SIZE(static_nodes_formats); i++) {
                                if (streq(static_nodes_formats[i]->name, optarg)) {
                                        format = static_nodes_formats[i];
                                        valid = 1;
                                }
                        }

                        if (!valid) {
                                fprintf(stderr, "Unknown format: '%s'.\n", optarg);
                                help();
                                ret = EXIT_FAILURE;
                                goto finish;
                        }
                        break;
                case 'h':
                        help();
                        goto finish;
                case '?':
                        ret = EXIT_FAILURE;
                        goto finish;
                default:
                        fprintf(stderr, "Unexpected commandline option '%c'.\n", c);
                        help();
                        ret = EXIT_FAILURE;
                        goto finish;
                }
        }

        if (uname(&kernel) < 0) {
                fputs("Error: uname failed!\n", stderr);
                ret = EXIT_FAILURE;
                goto finish;
        }

        snprintf(modules, sizeof(modules), "/lib/modules/%s/modules.devname", kernel.release);
        in = fopen(modules, "re");
        if (in == NULL) {
                fprintf(stderr, "Error: could not open /lib/modules/%s/modules.devname - %m\n", kernel.release);
                ret = EXIT_FAILURE;
                goto finish;
        }

        while (fgets(buf, sizeof(buf), in) != NULL) {
                char modname[PATH_MAX];
                char devname[PATH_MAX];
                char type;
                unsigned int maj, min;
                int matches;

                if (buf[0] == '#')
                        continue;

                matches = sscanf(buf, "%s %s %c%u:%u", modname, devname, &type, &maj, &min);
                if (matches != 5 || (type != 'c' && type != 'b')) {
                        fprintf(stderr, "Error: invalid devname entry: %s", buf);
                        ret = EXIT_FAILURE;
                        continue;
                }

                format->write(out, modname, devname, type, maj, min);
        }

finish:
        if (in)
                fclose(in);
        if (out)
                fclose(out);
        return ret;
}

const struct kmod_cmd kmod_cmd_static_nodes = {
	.name = "static-nodes",
	.cmd = do_static_nodes,
	.help = "outputs the static-node information installed with the currently running kernel",
};