uuuid.c

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/* -*- C -*- */
/*
 * Copyright (c) 2015-2020 Seagate Technology LLC and/or its Affiliates
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * For any questions about this software or licensing,
 * please email opensource@seagate.com or cortx-questions@seagate.com.
 *
 */



#define M0_TRACE_SUBSYSTEM M0_TRACE_SUBSYS_LIB
#include "lib/trace.h"
#include "lib/uuid.h"
#include "lib/errno.h"               /* EINVAL */

#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

enum {
        MACHINE_ID_LEN = 32
};
static const char *uuid_file = "/etc/machine-id";
static char default_node_uuid[M0_UUID_STRLEN + 1] =
                "00000000-0000-0000-0000-000000000000"; /* nil UUID */

static bool use_default_node_uuid = false;

void m0_kmod_uuid_file_set(const char *path)
{
        uuid_file = path;
}

void m0_node_uuid_string_set(const char *uuid)
{
        use_default_node_uuid = true;
        if (uuid != NULL) {
                strncpy(default_node_uuid, uuid, M0_UUID_STRLEN);
                default_node_uuid[M0_UUID_STRLEN] = '\0';
        }
}

int m0_node_uuid_string_get(char buf[M0_UUID_STRLEN + 1])
{
        int fd;
        int rc = 0;
        char mid[MACHINE_ID_LEN + 1];

        M0_BASSERT(MACHINE_ID_LEN == M0_UUID_STRLEN - 4);

        if (use_default_node_uuid) {
                strncpy(buf, default_node_uuid, M0_UUID_STRLEN + 1);
                buf[M0_UUID_STRLEN] = '\0';
        } else {
                fd = open(uuid_file, O_RDONLY);
                if (fd < 0) {
                        return M0_ERR_INFO(-EINVAL,
                                           "open(\"%s\", O_RDONLY)=%d "
                                           "errno=%d: ",
                                           uuid_file, fd, errno);
                }
                if (read(fd, mid, MACHINE_ID_LEN) == MACHINE_ID_LEN) {
                        rc = 0;
                        snprintf(buf, M0_UUID_STRLEN + 1,
                                "%.8s-%.4s-%.4s-%.4s-%.12s",
                                mid, mid + 8, mid + 8 + 4, mid + 8 + 4 + 4,
                                mid + 8 + 4 + 4 + 4);
                        buf[M0_UUID_STRLEN] = '\0';
                } else {
                        rc = M0_ERR_INFO(-EINVAL, "Incorrect data in %s",
                                         uuid_file);
                }
                close(fd);
        }

        return M0_RC(rc);
}

#undef M0_TRACE_SUBSYSTEM

/*
 *  Local variables:
 *  c-indentation-style: "K&R"
 *  c-basic-offset: 8
 *  tab-width: 8
 *  fill-column: 80
 *  scroll-step: 1
 *  End:
 */
/*
 * vim: tabstop=8 shiftwidth=8 noexpandtab textwidth=80 nowrap
 */