libuuid/common/uuid.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 2002, 2012, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * The copyright in this file is taken from the original Leach & Salz
 * UUID specification, from which this implementation is derived.
 */

/*
 * Copyright (c) 1990- 1993, 1996 Open Software Foundation, Inc.
 * Copyright (c) 1989 by Hewlett-Packard Company, Palo Alto, Ca. &
 * Digital Equipment Corporation, Maynard, Mass.  Copyright (c) 1998
 * Microsoft.  To anyone who acknowledges that this file is provided
 * "AS IS" without any express or implied warranty: permission to use,
 * copy, modify, and distribute this file for any purpose is hereby
 * granted without fee, provided that the above copyright notices and
 * this notice appears in all source code copies, and that none of the
 * names of Open Software Foundation, Inc., Hewlett-Packard Company,
 * or Digital Equipment Corporation be used in advertising or
 * publicity pertaining to distribution of the software without
 * specific, written prior permission.  Neither Open Software
 * Foundation, Inc., Hewlett-Packard Company, Microsoft, nor Digital
 * Equipment Corporation makes any representations about the
 * suitability of this software for any purpose.
 */

/*
 * This module is the workhorse for generating abstract
 * UUIDs.  It delegates system-specific tasks (such
 * as obtaining the node identifier or system time)
 * to the sysdep module.
 */

#include <ctype.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <fcntl.h>
#include <unistd.h>
#include <synch.h>
#include <sys/mman.h>
#include "uuid_misc.h"

shared_buffer_t     *data;

static  uuid_node_t node_id_cache;
static  int     node_init;
static  int     buffer_init;
static  int     file_type;
static  int     fd;

/*
 * misc routines
 */
uint16_t        get_random(void);
void            get_current_time(uuid_time_t *);

void            struct_to_string(uuid_t, struct uuid *);
void            string_to_struct(struct uuid *, uuid_t);
int         get_ethernet_address(uuid_node_t *);

/*
 * local functions
 */
static  int     map_state();
static  void        format_uuid(struct uuid *, uint16_t, uuid_time_t,
    uuid_node_t);
static  void        fill_random_bytes(uchar_t *, int);
static  int     uuid_create(struct uuid *);
static  void        gen_ethernet_address(uuid_node_t *);
static  void        revalidate_data(uuid_node_t *);

/*
 * Generates a uuid based on version 1 format.
 * Returns 0 on success and -1 on failure.
 */
static int
uuid_create(struct uuid *uuid)
{
    uuid_time_t timestamp;
    uuid_node_t system_node;
    int     ret, non_unique = 0;

    /*
     * Get the system MAC address and/or cache it
     */
    if (node_init) {
        bcopy(&node_id_cache, &system_node, sizeof (uuid_node_t));
    } else {
        gen_ethernet_address(&system_node);
        bcopy(&system_node, &node_id_cache, sizeof (uuid_node_t));
        node_init = 1;
    }

    /*
     * Access the state file, mmap it and initialize the shared lock.
     * file_type tells us whether we had access to the state file or
     * created a temporary one.
     */
    buffer_init = map_state();

    if (buffer_init == -1) {
        return (buffer_init);
    }

    /*
     * Acquire the lock
     */
    for (;;) {
        if ((ret = mutex_lock(&data->lock)) == 0)
            break;
        else
            switch (ret) {
                case EOWNERDEAD:
                    revalidate_data(&system_node);
                    (void) mutex_consistent(&data->lock);
                    (void) mutex_unlock(&data->lock);
                    break;
                case ENOTRECOVERABLE:
                    return (ret);
                    /* NOTREACHED */
                    break;
            }
    }

    /* State file is either new or is temporary, get a random clock seq */
    if (data->state.clock == 0) {
        data->state.clock = get_random();
        non_unique++;
    }

    if (memcmp(&system_node, &data->state.node, sizeof (uuid_node_t)) != 0)
        data->state.clock++;

    get_current_time(&timestamp);

    /*
     * If timestamp is not set or is not in the past, bump
     * data->state.clock
     */
    if ((data->state.ts == 0) || (data->state.ts >= timestamp)) {
        data->state.clock++;
        data->state.ts = timestamp;
    }

    if (non_unique)
        system_node.nodeID[0] |= 0x80;

    /* Stuff fields into the UUID struct */
    format_uuid(uuid, data->state.clock, timestamp, system_node);

    (void) mutex_unlock(&data->lock);

    return (0);
}

/*
 * Fills system_node with Ethernet address if available,
 * else fills random numbers
 */
static void
gen_ethernet_address(uuid_node_t *system_node)
{
    uchar_t     node[6];

    if (get_ethernet_address(system_node) != 0) {
        fill_random_bytes(node, 6);
        (void) memcpy(system_node->nodeID, node, 6);
        /*
         * use 8:0:20 with the multicast bit set
         * to avoid namespace collisions.
         */
        system_node->nodeID[0] = 0x88;
        system_node->nodeID[1] = 0x00;
        system_node->nodeID[2] = 0x20;
    }
}

/*
 * Formats a UUID, given the clock_seq timestamp, and node address.
 * Fills in passed-in pointer with the resulting uuid.
 */
static void
format_uuid(struct uuid *uuid, uint16_t clock_seq,
    uuid_time_t timestamp, uuid_node_t node)
{

    /*
     * First set up the first 60 bits from the timestamp
     */
    uuid->time_low = (uint32_t)(timestamp & 0xFFFFFFFF);
    uuid->time_mid = (uint16_t)((timestamp >> 32) & 0xFFFF);
    uuid->time_hi_and_version = (uint16_t)((timestamp >> 48) & 0x0FFF);

    /*
     * This is version 1, so say so in the UUID version field (4 bits)
     */
    uuid->time_hi_and_version |= (1 << 12);

    /*
     * Now do the clock sequence
     */
    uuid->clock_seq_low = clock_seq & 0xFF;

    /*
     * We must save the most-significant 2 bits for the reserved field
     */
    uuid->clock_seq_hi_and_reserved = (clock_seq & 0x3F00) >> 8;

    /*
     * The variant for this format is the 2 high bits set to 10,
     * so here it is
     */
    uuid->clock_seq_hi_and_reserved |= 0x80;

    /*
     * write result to passed-in pointer
     */
    (void) memcpy(&uuid->node_addr, &node, sizeof (uuid->node_addr));
}

/*
 * Opens/creates the state file, falling back to a tmp
 */
static int
map_state()
{
    char *tmpname;

    tmpname = strdup("/tmp/tmpfileXXXXXX");
    if (tmpname == NULL)
        return (-1);

    /* If file's mapped, return */
    if (file_type != 0) {
        free(tmpname);
        return (1);
    }

    if ((fd = open(STATE_LOCATION, O_RDWR)) < 0) {

        if ((fd = mkstemp(tmpname)) == -1) {
            free(tmpname);
            return (-1);
        } else {
            file_type = TEMP_FILE;
        }
    } else {
        file_type = STATE_FILE;
    }
    (void) unlink(tmpname);
    free(tmpname);

    (void) ftruncate(fd, (off_t)sizeof (shared_buffer_t));

    data = (shared_buffer_t *)mmap(NULL, sizeof (shared_buffer_t),
        PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);

    if (data == MAP_FAILED)
        return (-1);

    (void) mutex_init(&data->lock, USYNC_PROCESS|LOCK_ROBUST, 0);

    (void) close(fd);

    return (1);
}

static void
revalidate_data(uuid_node_t *node)
{
    int i;

    data->state.ts = 0;

    for (i = 0; i < sizeof (data->state.node.nodeID); i++)
        data->state.node.nodeID[i] = 0;

    data->state.clock = 0;

    gen_ethernet_address(node);
    bcopy(node, &node_id_cache, sizeof (uuid_node_t));
    node_init = 1;
}

/*
 * Prints a nicely-formatted uuid to stdout.
 */
void
uuid_print(struct uuid u)
{
    int i;

    (void) printf("%8.8x-%4.4x-%4.4x-%2.2x%2.2x-", u.time_low, u.time_mid,
        u.time_hi_and_version, u.clock_seq_hi_and_reserved,
        u.clock_seq_low);
    for (i = 0; i < 6; i++)
        (void) printf("%2.2x", u.node_addr[i]);
    (void) printf("\n");
}

/*
 * Fills buf with random numbers - nbytes is the number of bytes
 * to fill-in. Tries to use /dev/urandom random number generator-
 * if that fails for some reason, it retries MAX_RETRY times. If
 * it still fails then it uses srand48(3C)
 */
static void
fill_random_bytes(uchar_t *buf, int nbytes)
{
    int i, fd, retries = 0;

    fd = open(URANDOM_PATH, O_RDONLY);
    if (fd >= 0) {
        while (nbytes > 0) {
            i = read(fd, buf, nbytes);
            if ((i < 0) && (errno == EINTR)) {
                continue;
            }
            if (i <= 0) {
                if (retries++ == MAX_RETRY)
                    break;
                continue;
            }
            nbytes -= i;
            buf += i;
            retries = 0;
        }
        if (nbytes == 0) {
            (void) close(fd);
            return;
        }
    }
    for (i = 0; i < nbytes; i++) {
        *buf++ = get_random() & 0xFF;
    }
    if (fd >= 0) {
        (void) close(fd);
    }
}

/*
 * Unpacks the structure members in "struct uuid" to a char string "uuid_t".
 */
void
struct_to_string(uuid_t ptr, struct uuid *uu)
{
    uint_t      tmp;
    uchar_t     *out = ptr;

    tmp = uu->time_low;
    out[3] = (uchar_t)tmp;
    tmp >>= 8;
    out[2] = (uchar_t)tmp;
    tmp >>= 8;
    out[1] = (uchar_t)tmp;
    tmp >>= 8;
    out[0] = (uchar_t)tmp;

    tmp = uu->time_mid;
    out[5] = (uchar_t)tmp;
    tmp >>= 8;
    out[4] = (uchar_t)tmp;

    tmp = uu->time_hi_and_version;
    out[7] = (uchar_t)tmp;
    tmp >>= 8;
    out[6] = (uchar_t)tmp;

    tmp = uu->clock_seq_hi_and_reserved;
    out[8] = (uchar_t)tmp;
    tmp = uu->clock_seq_low;
    out[9] = (uchar_t)tmp;

    (void) memcpy(out+10, uu->node_addr, 6);

}

/*
 * Packs the values in the "uuid_t" string into "struct uuid".
 */
void
string_to_struct(struct uuid *uuid, uuid_t in)
{
    uchar_t *ptr;
    uint_t  tmp;

    ptr = in;

    tmp = *ptr++;
    tmp = (tmp << 8) | *ptr++;
    tmp = (tmp << 8) | *ptr++;
    tmp = (tmp << 8) | *ptr++;
    uuid->time_low = tmp;

    tmp = *ptr++;
    tmp = (tmp << 8) | *ptr++;
    uuid->time_mid = tmp;

    tmp = *ptr++;
    tmp = (tmp << 8) | *ptr++;
    uuid->time_hi_and_version = tmp;

    tmp = *ptr++;
    uuid->clock_seq_hi_and_reserved = tmp;

    tmp = *ptr++;
    uuid->clock_seq_low = tmp;

    (void) memcpy(uuid->node_addr, ptr, 6);

}

/*
 * Generates UUID based on DCE Version 4
 */
void
uuid_generate_random(uuid_t uu)
{
    struct uuid uuid;

    if (uu == NULL)
        return;

    (void) memset(uu, 0, sizeof (uuid_t));
    (void) memset(&uuid, 0, sizeof (struct uuid));

    fill_random_bytes(uu, sizeof (uuid_t));
    string_to_struct(&uuid, uu);
    /*
     * This is version 4, so say so in the UUID version field (4 bits)
     */
    uuid.time_hi_and_version |= (1 << 14);
    /*
     * we don't want the bit 1 to be set also which is for version 1
     */
    uuid.time_hi_and_version &= VER1_MASK;

    /*
     * The variant for this format is the 2 high bits set to 10,
     * so here it is
     */
    uuid.clock_seq_hi_and_reserved |= 0x80;

    /*
     * Set MSB of Ethernet address to 1 to indicate that it was generated
     * randomly
     */
    uuid.node_addr[0] |= 0x80;
    struct_to_string(uu, &uuid);
}

/*
 * Generates UUID based on DCE Version 1.
 */
void
uuid_generate_time(uuid_t uu)
{
    struct  uuid uuid;

    if (uu == NULL)
        return;

    if (uuid_create(&uuid) < 0) {
        uuid_generate_random(uu);
        return;
    }

    struct_to_string(uu, &uuid);
}

/*
 * Creates a new UUID. The uuid will be generated based on high-quality
 * randomness from /dev/urandom, if available by calling uuid_generate_random.
 * If it failed to generate UUID then uuid_generate will call
 * uuid_generate_time.
 */
void
uuid_generate(uuid_t uu)
{
    int fd;

    if (uu == NULL) {
        return;
    }
    fd = open(URANDOM_PATH, O_RDONLY);
    if (fd >= 0) {
        (void) close(fd);
        uuid_generate_random(uu);
    } else {
        (void) uuid_generate_time(uu);
    }
}

/*
 * Copies the UUID variable src to dst.
 */
void
uuid_copy(uuid_t dst, uuid_t src)
{
    (void) memcpy(dst, src, UUID_LEN);
}

/*
 * Sets the value of the supplied uuid variable uu, to the NULL value.
 */
void
uuid_clear(uuid_t uu)
{
    (void) memset(uu, 0, UUID_LEN);
}

/*
 * This function converts the supplied UUID uu from the internal
 * binary format into a 36-byte string (plus trailing null char)
 * and stores this value in the character string pointed to by out.
 */
void
uuid_unparse(uuid_t uu, char *out)
{
    struct uuid     uuid;
    uint16_t    clock_seq;
    char        etheraddr[13];
    int     index = 0, i;

    /* basic sanity checking */
    if (uu == NULL) {
        return;
    }

    /* XXX user should have allocated enough memory */
    /*
     * if (strlen(out) < UUID_PRINTABLE_STRING_LENGTH) {
     * return;
     * }
     */
    string_to_struct(&uuid, uu);
    clock_seq = uuid.clock_seq_hi_and_reserved;
    clock_seq = (clock_seq  << 8) | uuid.clock_seq_low;
    for (i = 0; i < 6; i++) {
        (void) sprintf(&etheraddr[index++], "%.2x", uuid.node_addr[i]);
        index++;
    }
    etheraddr[index] = '\0';

    (void) snprintf(out, 25, "%08x-%04x-%04x-%04x-",
        uuid.time_low, uuid.time_mid, uuid.time_hi_and_version, clock_seq);
    (void) strlcat(out, etheraddr, UUID_PRINTABLE_STRING_LENGTH);
}

/*
 * The uuid_is_null function compares the value of the supplied
 * UUID variable uu to the NULL value. If the value is equal
 * to the NULL UUID, 1 is returned, otherwise 0 is returned.
 */
int
uuid_is_null(uuid_t uu)
{
    int     i;
    uuid_t      null_uu;

    (void) memset(null_uu, 0, sizeof (uuid_t));
    i = memcmp(uu, null_uu, sizeof (uuid_t));
    if (i == 0) {
        /* uu is NULL uuid */
        return (1);
    } else {
        return (0);
    }
}

/*
 * uuid_parse converts the UUID string given by 'in' into the
 * internal uuid_t format. The input UUID is a string of the form
 * cefa7a9c-1dd2-11b2-8350-880020adbeef in printf(3C) format.
 * Upon successfully parsing the input string, UUID is stored
 * in the location pointed to by uu
 */
int
uuid_parse(char *in, uuid_t uu)
{

    char        *ptr, buf[3];
    int     i;
    struct uuid uuid;
    uint16_t    clock_seq;

    /* do some sanity checking */
    if ((strlen(in) != 36) || (uu == NULL) || (in[36] != '\0')) {
        return (-1);
    }

    ptr = in;
    for (i = 0; i < 36; i++, ptr++) {
        if ((i == 8) || (i == 13) || (i == 18) || (i == 23)) {
            if (*ptr != '-') {
                return (-1);
            }
        } else {
            if (!isxdigit(*ptr)) {
                return (-1);
            }
        }
    }

    uuid.time_low = strtoul(in, NULL, 16);
    uuid.time_mid = strtoul(in+9, NULL, 16);
    uuid.time_hi_and_version = strtoul(in+14, NULL, 16);
    clock_seq = strtoul(in+19, NULL, 16);
    uuid.clock_seq_hi_and_reserved = (clock_seq & 0xFF00) >> 8;
    uuid.clock_seq_low = (clock_seq & 0xFF);

    ptr = in+24;
    buf[2] = '\0';
    for (i = 0; i < 6; i++) {
        buf[0] = *ptr++;
        buf[1] = *ptr++;
        uuid.node_addr[i] = strtoul(buf, NULL, 16);
    }
    struct_to_string(uu, &uuid);
    return (0);
}

/*
 * uuid_time extracts the time at which the supplied UUID uu
 * was created. This function can only extract the creation
 * time for UUIDs created with the uuid_generate_time function.
 * The time at which the UUID was created, in seconds and
 * microseconds since the epoch is stored in the location
 * pointed to by ret_tv.
 */
time_t
uuid_time(uuid_t uu, struct timeval *ret_tv)
{
    struct uuid uuid;
    uint_t      high;
    struct timeval  tv;
    u_longlong_t    clock_reg;
    uint_t      tmp;
    uint8_t     clk;

    string_to_struct(&uuid, uu);
    tmp = (uuid.time_hi_and_version & 0xF000) >> 12;
    clk = uuid.clock_seq_hi_and_reserved;

    /* check if uu is NULL, Version = 1 of DCE and Variant = 0b10x */
    if ((uu == NULL) || ((tmp & 0x01) != 0x01) || ((clk & 0x80) != 0x80)) {
        return (-1);
    }
    high = uuid.time_mid | ((uuid.time_hi_and_version & 0xFFF) << 16);
    clock_reg = uuid.time_low | ((u_longlong_t)high << 32);

    clock_reg -= (((u_longlong_t)0x01B21DD2) << 32) + 0x13814000;
    tv.tv_sec = clock_reg / 10000000;
    tv.tv_usec = (clock_reg % 10000000) / 10;

    if (ret_tv) {
        *ret_tv = tv;
    }

    return (tv.tv_sec);
}