FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_uuid.c

     /*-
      * Copyright (c) 2002 Marcel Moolenaar
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      *
      * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     *
     * $FreeBSD: src/sys/kern/kern_uuid.c,v 1.13 2007/04/23 12:53:00 pjd Exp $
     * $DragonFly: src/sys/kern/kern_uuid.c,v 1.4 2007/06/19 06:07:57 dillon Exp $
     */
    
    #include <sys/param.h>
    #include <sys/endian.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/kern_syscall.h>
    #include <sys/random.h>
    #include <sys/sbuf.h>
    #include <sys/socket.h>
    #include <sys/sysproto.h>
    #include <sys/uuid.h>
    #include <sys/gpt.h>
    #include <net/if_var.h>
    
    /*
     * See also:
     *      http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
     *      http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
     *
     * Note that the generator state is itself an UUID, but the time and clock
     * sequence fields are written in the native byte order.
     */
    
    /* We use an alternative, more convenient representation in the generator. */
    struct uuid_private {
            union {
                    uint64_t        ll;             /* internal. */
                    struct {
                            uint32_t        low;
                            uint16_t        mid;
                            uint16_t        hi;
                    } x;
            } time;
            uint16_t        seq;                    /* Big-endian. */
            uint16_t        node[UUID_NODE_LEN>>1];
    };
    
    static struct uuid_private uuid_last;
    
    static struct lock uuid_lock;
    
    static
    void
    uuid_lock_init(void *arg __unused)
    {
            lockinit(&uuid_lock, "uuid", 0, 0);
    }
    SYSINIT(uuid_lock, SI_BOOT1_POST, SI_ORDER_ANY, uuid_lock_init, NULL);
    
    /*
     * Ask the network subsystem for a real MAC address from any of the
     * system interfaces.  If we can't find one, generate a random multicast
     * MAC address.
     */
    static void
    uuid_node(uint16_t *node)
    {
            if (if_getanyethermac(node, UUID_NODE_LEN) != 0)
                    read_random(node, UUID_NODE_LEN);
            *((uint8_t*)node) |= 0x01;
    }
    
    /*
     * Get the current time as a 60 bit count of 100-nanosecond intervals
     * since 00:00:00.00, October 15,1582. We apply a magic offset to convert
     * the Unix time since 00:00:00.00, January 1, 1970 to the date of the
     * Gregorian reform to the Christian calendar.
     */
    static uint64_t
    uuid_time(void)
   {
           struct timespec ts;
           uint64_t time = 0x01B21DD213814000LL;
   
           nanotime(&ts);
           time += ts.tv_sec * 10000000LL;         /* 100 ns increments */
           time += ts.tv_nsec / 100;               /* 100 ns increments */
           return (time & ((1LL << 60) - 1LL));    /* limit to 60 bits */
   }
   
   struct uuid *
   kern_uuidgen(struct uuid *store, size_t count)
   {
           struct uuid_private uuid;
           uint64_t time;
           size_t n;
   
           lockmgr(&uuid_lock, LK_EXCLUSIVE | LK_RETRY);
   
           uuid_node(uuid.node);
           time = uuid_time();
   
           if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] ||
               uuid_last.node[1] != uuid.node[1] ||
               uuid_last.node[2] != uuid.node[2]) {
                   read_random(&uuid.seq, sizeof(uuid.seq));
                   uuid.seq &= 0x3fff;
           } else if (uuid_last.time.ll >= time) {
                   uuid.seq = (uuid_last.seq + 1) & 0x3fff;
           } else {
                   uuid.seq = uuid_last.seq;
           }
   
           uuid_last = uuid;
           uuid_last.time.ll = (time + count - 1) & ((1LL << 60) - 1LL);
   
           lockmgr(&uuid_lock, LK_RELEASE);
   
           /* Set sequence and variant and deal with byte order. */
           uuid.seq = htobe16(uuid.seq | 0x8000);
   
           for (n = 0; n < count; n++) {
                   /* Set time and version (=1). */
                   uuid.time.x.low = (uint32_t)time;
                   uuid.time.x.mid = (uint16_t)(time >> 32);
                   uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12);
                   store[n] = *(struct uuid *)&uuid;
                   time++;
           }
   
           return (store);
   }
   
   /*
    * uuidgen(struct uuid *store, int count)
    *
    * Generate an array of new UUIDs
    */
   int
   sys_uuidgen(struct uuidgen_args *uap)
   {
           struct uuid *store;
           size_t count;
           int error;
   
           /*
            * Limit the number of UUIDs that can be created at the same time
            * to some arbitrary number. This isn't really necessary, but I
            * like to have some sort of upper-bound that's less than 2G :-)
            * XXX probably needs to be tunable.
            */
           if (uap->count < 1 || uap->count > 2048)
                   return (EINVAL);
   
           count = uap->count;
           store = kmalloc(count * sizeof(struct uuid), M_TEMP, M_WAITOK|M_NULLOK);
           if (store == NULL)
                   return (ENOSPC);
           kern_uuidgen(store, count);
           error = copyout(store, uap->store, count * sizeof(struct uuid));
           kfree(store, M_TEMP);
           return (error);
   }
   
   int
   snprintf_uuid(char *buf, size_t sz, struct uuid *uuid)
   {
           struct uuid_private *id;
           int cnt;
   
           id = (struct uuid_private *)uuid;
           cnt = ksnprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x",
               id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq),
               be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2]));
           return (cnt);
   }
   
   int
   printf_uuid(struct uuid *uuid)
   {
           char buf[38];
   
           snprintf_uuid(buf, sizeof(buf), uuid);
           return (kprintf("%s", buf));
   }
   
   int
   sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid)
   {
           char buf[38];
   
           snprintf_uuid(buf, sizeof(buf), uuid);
           return (sbuf_printf(sb, "%s", buf));
   }
   
   /*
    * Test functions
    */
   
   /* A macro used to improve the readability of uuid_compare(). */
   #define DIFF_RETURN(a, b, field)        do {                    \
           if ((a)->field != (b)->field)                           \
                   return (((a)->field < (b)->field) ? -1 : 1);    \
   } while (0)
   
   /*
    * kuuid_compare() - compare two UUIDs.
    * See also:
    *      http://www.opengroup.org/onlinepubs/009629399/uuid_compare.htm
    *
    * NOTE: Either UUID can be NULL, meaning a nil UUID. nil UUIDs are smaller
    *       than any non-nil UUID.
    */
   int
   kuuid_compare(const struct uuid *a, const struct uuid *b)
   {
           int     res;
   
           /* Deal with NULL or equal pointers. */
           if (a == b)
                   return (0);
           if (a == NULL)
                   return ((kuuid_is_nil(b)) ? 0 : -1);
           if (b == NULL)
                   return ((kuuid_is_nil(a)) ? 0 : 1);
   
           /* We have to compare the hard way. */
           DIFF_RETURN(a, b, time_low);
           DIFF_RETURN(a, b, time_mid);
           DIFF_RETURN(a, b, time_hi_and_version);
           DIFF_RETURN(a, b, clock_seq_hi_and_reserved);
           DIFF_RETURN(a, b, clock_seq_low);
   
           res = bcmp(a->node, b->node, sizeof(a->node));
           if (res)
                   return ((res < 0) ? -1 : 1);
           return (0);
   }
   
   #undef DIFF_RETURN
   
   int
   kuuid_is_nil(const struct uuid *uuid)
   {
           int i;
   
           for (i = 0; i < sizeof(*uuid); i += sizeof(int)) {
                   if (*(const int *)((const char *)uuid + i) != 0)
                           return(0);
           }
           return(1);
   }
   
   int
   kuuid_is_ccd(const struct uuid *uuid)
   {
           static struct uuid ccd_uuid = GPT_ENT_TYPE_DRAGONFLY_CCD;
           return(kuuid_compare(uuid, &ccd_uuid) == 0);
   }
   
   int
   kuuid_is_vinum(const struct uuid *uuid)
   {
           static struct uuid vinum_uuid = GPT_ENT_TYPE_DRAGONFLY_VINUM;
           return(kuuid_compare(uuid, &vinum_uuid) == 0);
   }
   
   /*
    * Encode/Decode UUID into byte-stream.
    *   http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
    *
    * 0                   1                   2                   3
    *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    *  |                          time_low                             |
    *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    *  |       time_mid                |         time_hi_and_version   |
    *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    *  |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
    *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    *  |                         node (2-5)                            |
    *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    */
   
   void
   le_uuid_enc(void *buf, struct uuid const *uuid)
   {
           u_char *p;
           int i;
   
           p = buf;
           le32enc(p, uuid->time_low);
           le16enc(p + 4, uuid->time_mid);
           le16enc(p + 6, uuid->time_hi_and_version);
           p[8] = uuid->clock_seq_hi_and_reserved;
           p[9] = uuid->clock_seq_low;
           for (i = 0; i < _UUID_NODE_LEN; i++)
                   p[10 + i] = uuid->node[i];
   }
   
   void
   le_uuid_dec(void const *buf, struct uuid *uuid)
   {
           u_char const *p;
           int i;
   
           p = buf;
           uuid->time_low = le32dec(p);
           uuid->time_mid = le16dec(p + 4);
           uuid->time_hi_and_version = le16dec(p + 6);
           uuid->clock_seq_hi_and_reserved = p[8];
           uuid->clock_seq_low = p[9];
           for (i = 0; i < _UUID_NODE_LEN; i++)
                   uuid->node[i] = p[10 + i];
   }
   
   void
   be_uuid_enc(void *buf, struct uuid const *uuid)
   {
           u_char *p;
           int i;
   
           p = buf;
           be32enc(p, uuid->time_low);
           be16enc(p + 4, uuid->time_mid);
           be16enc(p + 6, uuid->time_hi_and_version);
           p[8] = uuid->clock_seq_hi_and_reserved;
           p[9] = uuid->clock_seq_low;
           for (i = 0; i < _UUID_NODE_LEN; i++)
                   p[10 + i] = uuid->node[i];
   }
   
   void
   be_uuid_dec(void const *buf, struct uuid *uuid)
   {
           u_char const *p;
           int i;
   
           p = buf;
           uuid->time_low = be32dec(p);
           uuid->time_mid = le16dec(p + 4);
           uuid->time_hi_and_version = be16dec(p + 6);
           uuid->clock_seq_hi_and_reserved = p[8];
           uuid->clock_seq_low = p[9];
           for (i = 0; i < _UUID_NODE_LEN; i++)
                   uuid->node[i] = p[10 + i];
   }
   
   int
   parse_uuid(const char *str, struct uuid *uuid)
   {
           u_int c[11];
           int n;
   
           /* An empty string represents a nil UUID. */
           if (*str == '\0') {
                   bzero(uuid, sizeof(*uuid));
                   return (0);
           }
   
           /* The UUID string representation has a fixed length. */
           if (strlen(str) != 36)
                   return (EINVAL);
   
           /*
            * We only work with "new" UUIDs. New UUIDs have the form:
            *      01234567-89ab-cdef-0123-456789abcdef
            * The so called "old" UUIDs, which we don't support, have the form:
            *      0123456789ab.cd.ef.01.23.45.67.89.ab
            */
           if (str[8] != '-')
                   return (EINVAL);
   
           n = ksscanf(str, "%8x-%4x-%4x-%2x%2x-%2x%2x%2x%2x%2x%2x", c + 0, c + 1,
               c + 2, c + 3, c + 4, c + 5, c + 6, c + 7, c + 8, c + 9, c + 10);
           /* Make sure we have all conversions. */
           if (n != 11)
                   return (EINVAL);
   
           /* Successful scan. Build the UUID. */
           uuid->time_low = c[0];
           uuid->time_mid = c[1];
           uuid->time_hi_and_version = c[2];
           uuid->clock_seq_hi_and_reserved = c[3];
           uuid->clock_seq_low = c[4];
           for (n = 0; n < 6; n++)
                   uuid->node[n] = c[n + 5];
   
           /* Check semantics... */
           return (((c[3] & 0x80) != 0x00 &&               /* variant 0? */
               (c[3] & 0xc0) != 0x80 &&                    /* variant 1? */
               (c[3] & 0xe0) != 0xc0) ? EINVAL : 0);       /* variant 2? */
   }

Cache object: 3833dcefe0b4069930a5e8cfae6a77a1