56 lines
1.1 KiB
C
56 lines
1.1 KiB
C
/*-
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* See the file LICENSE for redistribution information.
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*
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* Copyright (c) 2001,2008 Oracle. All rights reserved.
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*
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* $Id: os_uid.c 63573 2008-05-23 21:43:21Z trent.nelson $
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*/
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#include "db_config.h"
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#include "db_int.h"
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/*
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* __os_unique_id --
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* Return a unique 32-bit value.
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*
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* PUBLIC: void __os_unique_id __P((ENV *, u_int32_t *));
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*/
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void
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__os_unique_id(env, idp)
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ENV *env;
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u_int32_t *idp;
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{
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DB_ENV *dbenv;
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db_timespec v;
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pid_t pid;
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u_int32_t id;
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*idp = 0;
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dbenv = env == NULL ? NULL : env->dbenv;
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/*
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* Our randomized value is comprised of our process ID, the current
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* time of day and a stack address, all XOR'd together.
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*/
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__os_id(dbenv, &pid, NULL);
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__os_gettime(env, &v, 1);
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id = (u_int32_t)pid ^
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(u_int32_t)v.tv_sec ^ (u_int32_t)v.tv_nsec ^ P_TO_UINT32(&pid);
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/*
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* We could try and find a reasonable random-number generator, but
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* that's not all that easy to do. Seed and use srand()/rand(), if
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* we can find them.
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*/
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if (DB_GLOBAL(uid_init) == 0) {
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DB_GLOBAL(uid_init) = 1;
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srand((u_int)id);
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}
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id ^= (u_int)rand();
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*idp = id;
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}
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