d4-core/client/others/uuid/gen_uuid.c

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/*
* gen_uuid.c --- generate a DCE-compatible uuid
*
* Copyright (C) 1996, 1997, 1998, 1999 Theodore Ts'o.
*
* %Begin-Header%
* 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, and the entire permission notice in its entirety,
* including the disclaimer of warranties.
* 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.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
* WHICH ARE HEREBY 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 NOT ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
* %End-Header%
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include "uuidP.h"
#include "randutils.h"
#ifdef HAVE_TLS
#define THREAD_LOCAL static __thread
#else
#define THREAD_LOCAL static
#endif
/*
* Try using the uuidd daemon to generate the UUID
*
* Returns 0 on success, non-zero on failure.
*/
void __uuid_generate_random(uuid_t out, int *num)
{
uuid_t buf;
struct uuid uu;
int i, n;
if (!num || !*num)
n = 1;
else
n = *num;
for (i = 0; i < n; i++) {
random_get_bytes(buf, sizeof(buf));
uuid_unpack(buf, &uu);
uu.clock_seq = (uu.clock_seq & 0x3FFF) | 0x8000;
uu.time_hi_and_version = (uu.time_hi_and_version & 0x0FFF)
| 0x4000;
uuid_pack(&uu, out);
out += sizeof(uuid_t);
}
}
void uuid_generate_random(uuid_t out)
{
int num = 1;
/* No real reason to use the daemon for random uuid's -- yet */
__uuid_generate_random(out, &num);
}
/*
* Check whether good random source (/dev/random or /dev/urandom)
* is available.
*/
static int have_random_source(void)
{
return (access("/dev/random", R_OK) == 0 ||
access("/dev/urandom", R_OK) == 0);
}
/*
* This is the generic front-end to uuid_generate_random and
* uuid_generate_time. It uses uuid_generate_random only if
* /dev/urandom is available, since otherwise we won't have
* high-quality randomness.
*/
void uuid_generate(uuid_t out)
{
if (have_random_source())
uuid_generate_random(out);
}