libvirt/src/util/uuid.c

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/*
* Copyright (C) 2007, 2008, 2009, 2010 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors:
* Mark McLoughlin <markmc@redhat.com>
*/
#include <config.h>
#include "uuid.h"
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
#include "c-ctype.h"
#include "internal.h"
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#include "util.h"
#include "virterror_internal.h"
#include "logging.h"
#include "memory.h"
#ifndef ENODATA
# define ENODATA EIO
#endif
static unsigned char host_uuid[VIR_UUID_BUFLEN];
static int
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virUUIDGenerateRandomBytes(unsigned char *buf,
int buflen)
{
int fd;
if ((fd = open("/dev/urandom", O_RDONLY)) < 0)
return errno;
while (buflen > 0) {
int n;
if ((n = read(fd, buf, buflen)) <= 0) {
if (errno == EINTR)
continue;
close(fd);
return n < 0 ? errno : ENODATA;
}
buf += n;
buflen -= n;
}
close(fd);
return 0;
}
static int
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virUUIDGeneratePseudoRandomBytes(unsigned char *buf,
int buflen)
{
while (buflen > 0) {
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*buf = virRandom(256);
buflen--;
}
return 0;
}
/**
* virUUIDGenerate:
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* @uuid: array of VIR_UUID_BUFLEN bytes to store the new UUID
*
* Generates a randomized unique identifier.
*
* Returns 0 in case of success and -1 in case of failure
*/
int
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virUUIDGenerate(unsigned char *uuid)
{
int err;
if (uuid == NULL)
return(-1);
if ((err = virUUIDGenerateRandomBytes(uuid, VIR_UUID_BUFLEN))) {
char ebuf[1024];
VIR_WARN("Falling back to pseudorandom UUID,"
" failed to generate random bytes: %s",
virStrerror(err, ebuf, sizeof ebuf));
err = virUUIDGeneratePseudoRandomBytes(uuid, VIR_UUID_BUFLEN);
}
return(err);
}
/**
* virUUIDParse:
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* @uuidstr: zero terminated string representation of the UUID
* @uuid: array of VIR_UUID_BUFLEN bytes to store the raw UUID
*
* Parses the external string representation, allowing spaces and '-'
* character in the sequence, and storing the result as a raw UUID
*
* Returns 0 in case of success and -1 in case of error.
*/
int
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virUUIDParse(const char *uuidstr, unsigned char *uuid) {
const char *cur;
int i;
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if ((uuidstr == NULL) || (uuid == NULL))
return(-1);
/*
* do a liberal scan allowing '-' and ' ' anywhere between character
* pairs, and surrounding whitespace, as long as there are exactly
* 32 hexadecimal digits the end.
*/
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cur = uuidstr;
while (c_isspace(*cur))
cur++;
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for (i = 0;i < VIR_UUID_BUFLEN;) {
uuid[i] = 0;
if (*cur == 0)
goto error;
if ((*cur == '-') || (*cur == ' ')) {
cur++;
continue;
}
if (!c_isxdigit(*cur))
goto error;
uuid[i] = virHexToBin(*cur);
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uuid[i] *= 16;
cur++;
if (*cur == 0)
goto error;
if (!c_isxdigit(*cur))
goto error;
uuid[i] += virHexToBin(*cur);
i++;
cur++;
}
while (*cur) {
if (!c_isspace(*cur))
goto error;
cur++;
}
return 0;
error:
return -1;
}
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/**
* virUUIDFormat:
* @uuid: array of VIR_UUID_RAW_LEN bytes to store the raw UUID
* @uuidstr: array of VIR_UUID_STRING_BUFLEN bytes to store the
* string representation of the UUID in. The resulting string
* will be NULL terminated.
*
* Converts the raw UUID into printable format, with embedded '-'
*
* Returns 0 in case of success and -1 in case of error.
*/
void virUUIDFormat(const unsigned char *uuid, char *uuidstr)
{
snprintf(uuidstr, VIR_UUID_STRING_BUFLEN,
"%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
uuid[0], uuid[1], uuid[2], uuid[3],
uuid[4], uuid[5], uuid[6], uuid[7],
uuid[8], uuid[9], uuid[10], uuid[11],
uuid[12], uuid[13], uuid[14], uuid[15]);
uuidstr[VIR_UUID_STRING_BUFLEN-1] = '\0';
}
/**
* virUUIDIsValid
*
* @uuid: The UUID to test
*
* Do some basic tests to check whether the given UUID is
* valid as a host UUID.
* Basic tests:
* - Not all of the digits may be equal
*/
int
virUUIDIsValid(unsigned char *uuid)
{
unsigned int i, ctr = 1;
unsigned char c;
if (!uuid)
return 0;
c = uuid[0];
for (i = 1; i < VIR_UUID_BUFLEN; i++)
if (uuid[i] == c)
ctr++;
return (ctr != VIR_UUID_BUFLEN);
}
static int
getDMISystemUUID(char *uuid, int len)
{
unsigned int i = 0;
const char *paths[] = {
"/sys/devices/virtual/dmi/id/product_uuid",
"/sys/class/dmi/id/product_uuid",
NULL
};
while (paths[i]) {
int fd = open(paths[i], O_RDONLY);
if (fd > 0) {
if (saferead(fd, uuid, len) == len) {
close(fd);
return 0;
}
close(fd);
}
i++;
}
return -1;
}
/**
* setHostUUID
*
* @host_uuid: UUID that the host is supposed to have
*
* Set the UUID of the host if it hasn't been set, yet
* Returns 0 in case of success, an error code in case of error.
*/
int
virSetHostUUIDStr(const char *uuid)
{
int rc;
char dmiuuid[VIR_UUID_STRING_BUFLEN];
if (virUUIDIsValid(host_uuid))
return EEXIST;
if (!uuid) {
memset(dmiuuid, 0, sizeof(dmiuuid));
if (!getDMISystemUUID(dmiuuid, sizeof(dmiuuid) - 1)) {
if (!virUUIDParse(dmiuuid, host_uuid))
return 0;
}
if (!virUUIDIsValid(host_uuid))
return virUUIDGenerate(host_uuid);
} else {
rc = virUUIDParse(uuid, host_uuid);
if (rc)
return rc;
if (!virUUIDIsValid(host_uuid))
return EINVAL;
}
return 0;
}
/**
* getHostUUID:
*
* @host_uuid: memory to store the host_uuid into
*
* Get the UUID of the host. Returns 0 in case of success,
* an error code otherwise.
* Returns 0 in case of success, an error code in case of error.
*/
int virGetHostUUID(unsigned char *uuid)
{
int ret = 0;
if (!virUUIDIsValid(host_uuid))
ret = virSetHostUUIDStr(NULL);
memcpy(uuid, host_uuid, sizeof(host_uuid));
return ret;
}