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e95ef67b35
The old virRandom() API was not generating good random numbers. Replace it with a new API virRandomBits which instead of being told the upper limit, gets told the number of bits of randomness required. * src/util/virrandom.c, src/util/virrandom.h: Add virRandomBits, and move virRandomInitialize * src/util/util.h, src/util/util.c: Delete virRandom and virRandomInitialize * src/libvirt.c, src/security/security_selinux.c, src/test/test_driver.c, src/util/iohelper.c: Update for changes from virRandom to virRandomBits * src/storage/storage_backend_iscsi.c: Remove bogus call to virRandomInitialize & convert to virRandomBits
82 lines
2.2 KiB
C
82 lines
2.2 KiB
C
/*
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* Copyright (C) 2012 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Authors:
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* Daniel P. Berrange <berrange@redhat.com>
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*/
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#include <config.h>
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#include <stdlib.h>
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#include "virrandom.h"
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#include "threads.h"
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#include "count-one-bits.h"
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static char randomState[128];
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static struct random_data randomData;
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static virMutex randomLock;
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int virRandomInitialize(uint32_t seed)
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{
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if (virMutexInit(&randomLock) < 0)
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return -1;
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if (initstate_r(seed,
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randomState,
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sizeof(randomState),
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&randomData) < 0)
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return -1;
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return 0;
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}
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/*
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* virRandomBits:
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* @nbits: Number of bits of randommess required
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*
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* Generate an evenly distributed random number between [0,2^nbits), where
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* @nbits must be in the range (0,64].
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*
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* Return: a random number with @nbits entropy
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*/
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uint64_t virRandomBits(int nbits)
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{
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int bits_per_iter = count_one_bits(RAND_MAX);
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uint64_t ret = 0;
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int32_t bits;
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/* This algorithm requires that RAND_MAX == 2^n-1 for some n;
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gnulib's random_r meets this property. */
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verify(((RAND_MAX + 1U) & RAND_MAX) == 0);
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virMutexLock(&randomLock);
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while (nbits > bits_per_iter) {
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random_r(&randomData, &bits);
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ret = (ret << bits_per_iter) | (bits & RAND_MAX);
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nbits -= bits_per_iter;
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}
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random_r(&randomData, &bits);
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ret = (ret << nbits) | (bits & ((1 << nbits) - 1));
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virMutexUnlock(&randomLock);
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return ret;
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}
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