mirror of
https://gitlab.com/libvirt/libvirt.git
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339 lines
7.8 KiB
C
339 lines
7.8 KiB
C
/*
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* viruuid.c: helper APIs for dealing with UUIDs
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*
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* Copyright (C) 2007-2014 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, see
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* <http://www.gnu.org/licenses/>.
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*
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* Authors:
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* Mark McLoughlin <markmc@redhat.com>
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*/
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#include <config.h>
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#include "viruuid.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <time.h>
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#include <unistd.h>
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#include "c-ctype.h"
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#include "internal.h"
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#include "virutil.h"
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#include "virerror.h"
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#include "virlog.h"
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#include "viralloc.h"
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#include "virfile.h"
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#include "virrandom.h"
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VIR_LOG_INIT("util.uuid");
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#ifndef ENODATA
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# define ENODATA EIO
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#endif
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static unsigned char host_uuid[VIR_UUID_BUFLEN];
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static int
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virUUIDGenerateRandomBytes(unsigned char *buf,
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int buflen)
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{
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int fd;
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if ((fd = open("/dev/urandom", O_RDONLY)) < 0)
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return errno;
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while (buflen > 0) {
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int n;
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if ((n = read(fd, buf, buflen)) <= 0) {
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if (errno == EINTR)
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continue;
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VIR_FORCE_CLOSE(fd);
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return n < 0 ? errno : ENODATA;
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}
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buf += n;
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buflen -= n;
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}
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VIR_FORCE_CLOSE(fd);
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return 0;
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}
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static int
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virUUIDGeneratePseudoRandomBytes(unsigned char *buf,
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int buflen)
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{
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while (buflen > 0) {
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*buf++ = virRandomBits(8);
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buflen--;
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}
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return 0;
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}
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/**
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* virUUIDGenerate:
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* @uuid: array of VIR_UUID_BUFLEN bytes to store the new UUID
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*
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* Generates a randomized unique identifier.
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*
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* Returns 0 in case of success and -1 in case of failure
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*/
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int
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virUUIDGenerate(unsigned char *uuid)
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{
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int err;
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if (uuid == NULL)
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return -1;
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if ((err = virUUIDGenerateRandomBytes(uuid, VIR_UUID_BUFLEN))) {
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char ebuf[1024];
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VIR_WARN("Falling back to pseudorandom UUID,"
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" failed to generate random bytes: %s",
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virStrerror(err, ebuf, sizeof(ebuf)));
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err = virUUIDGeneratePseudoRandomBytes(uuid, VIR_UUID_BUFLEN);
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}
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/*
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* Make UUID RFC 4122 compliant. Following form will be used:
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*
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* xxxxxxxx-xxxx-Axxx-Bxxx-xxxxxxxxxxxx
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*
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* where
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* A is version defined in 4.1.3 of RFC
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* Msb0 Msb1 Msb2 Msb3 Version Description
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* 0 1 0 0 4 The randomly or pseudo-
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* randomly generated version
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* specified in this document.
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*
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* B is variant defined in 4.1.1 of RFC
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* Msb0 Msb1 Msb2 Description
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* 1 0 x The variant specified in this document.
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*/
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uuid[6] = (uuid[6] & 0x0F) | (4 << 4);
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uuid[8] = (uuid[8] & 0x3F) | (2 << 6);
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return err;
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}
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/**
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* virUUIDParse:
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* @uuidstr: zero terminated string representation of the UUID
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* @uuid: array of VIR_UUID_BUFLEN bytes to store the raw UUID
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*
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* Parses the external string representation, allowing spaces and '-'
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* character in the sequence, and storing the result as a raw UUID
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*
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* Returns 0 in case of success and -1 in case of error.
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*/
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int
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virUUIDParse(const char *uuidstr, unsigned char *uuid)
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{
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const char *cur;
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size_t i;
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/*
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* do a liberal scan allowing '-' and ' ' anywhere between character
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* pairs, and surrounding whitespace, as long as there are exactly
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* 32 hexadecimal digits the end.
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*/
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cur = uuidstr;
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while (c_isspace(*cur))
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cur++;
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for (i = 0; i < VIR_UUID_BUFLEN;) {
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uuid[i] = 0;
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if (*cur == 0)
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goto error;
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if ((*cur == '-') || (*cur == ' ')) {
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cur++;
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continue;
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}
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if (!c_isxdigit(*cur))
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goto error;
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uuid[i] = virHexToBin(*cur);
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uuid[i] *= 16;
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cur++;
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if (*cur == 0)
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goto error;
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if (!c_isxdigit(*cur))
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goto error;
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uuid[i] += virHexToBin(*cur);
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i++;
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cur++;
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}
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while (*cur) {
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if (!c_isspace(*cur))
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goto error;
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cur++;
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}
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return 0;
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error:
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return -1;
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}
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/**
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* virUUIDFormat:
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* @uuid: array of VIR_UUID_RAW_LEN bytes to store the raw UUID
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* @uuidstr: array of VIR_UUID_STRING_BUFLEN bytes to store the
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* string representation of the UUID in. The resulting string
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* will be NULL terminated.
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*
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* Converts the raw UUID into printable format, with embedded '-'
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*
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* Returns a pointer to the resulting character string.
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*/
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const char *
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virUUIDFormat(const unsigned char *uuid, char *uuidstr)
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{
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snprintf(uuidstr, VIR_UUID_STRING_BUFLEN,
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"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
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uuid[0], uuid[1], uuid[2], uuid[3],
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uuid[4], uuid[5], uuid[6], uuid[7],
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uuid[8], uuid[9], uuid[10], uuid[11],
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uuid[12], uuid[13], uuid[14], uuid[15]);
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uuidstr[VIR_UUID_STRING_BUFLEN-1] = '\0';
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return uuidstr;
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}
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/**
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* virUUIDIsValid
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*
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* @uuid: The UUID to test
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*
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* Do some basic tests to check whether the given UUID is
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* valid as a host UUID.
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* Basic tests:
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* - Not all of the digits may be equal
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*/
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int
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virUUIDIsValid(unsigned char *uuid)
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{
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size_t i;
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unsigned int ctr = 1;
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unsigned char c;
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if (!uuid)
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return 0;
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c = uuid[0];
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for (i = 1; i < VIR_UUID_BUFLEN; i++)
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if (uuid[i] == c)
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ctr++;
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return ctr != VIR_UUID_BUFLEN;
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}
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static int
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getDMISystemUUID(char *uuid, int len)
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{
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size_t i = 0;
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const char *paths[] = {
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"/sys/devices/virtual/dmi/id/product_uuid",
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"/sys/class/dmi/id/product_uuid",
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NULL
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};
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while (paths[i]) {
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int fd = open(paths[i], O_RDONLY);
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if (fd >= 0) {
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if (saferead(fd, uuid, len - 1) == len - 1) {
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uuid[len - 1] = '\0';
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VIR_FORCE_CLOSE(fd);
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return 0;
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}
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VIR_FORCE_CLOSE(fd);
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}
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i++;
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}
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return -1;
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}
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/**
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* setHostUUID
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*
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* @host_uuid: UUID that the host is supposed to have
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*
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* Set the UUID of the host if it hasn't been set, yet
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* Returns 0 in case of success, an error code in case of error.
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*/
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int
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virSetHostUUIDStr(const char *uuid)
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{
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int rc;
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char dmiuuid[VIR_UUID_STRING_BUFLEN];
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if (virUUIDIsValid(host_uuid))
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return EEXIST;
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if (!uuid) {
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memset(dmiuuid, 0, sizeof(dmiuuid));
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if (!getDMISystemUUID(dmiuuid, sizeof(dmiuuid))) {
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if (!virUUIDParse(dmiuuid, host_uuid))
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return 0;
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}
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if (!virUUIDIsValid(host_uuid))
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return virUUIDGenerate(host_uuid);
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} else {
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rc = virUUIDParse(uuid, host_uuid);
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if (rc)
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return rc;
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if (!virUUIDIsValid(host_uuid))
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return EINVAL;
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}
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return 0;
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}
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/**
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* getHostUUID:
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*
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* @host_uuid: memory to store the host_uuid into
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*
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* Get the UUID of the host. Returns 0 in case of success,
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* an error code otherwise.
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* Returns 0 in case of success, an error code in case of error.
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*/
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int virGetHostUUID(unsigned char *uuid)
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{
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int ret = 0;
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if (!virUUIDIsValid(host_uuid))
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ret = virSetHostUUIDStr(NULL);
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memcpy(uuid, host_uuid, sizeof(host_uuid));
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return ret;
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}
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