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/*
* QEMU NVMe NGUID functions
*
* Copyright 2024 Google LLC
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License
* for more details.
*/
#include "qemu/osdep.h"
#include "qapi/visitor.h"
#include "qemu/ctype.h"
#include "nvme.h"
#define NGUID_SEPARATOR '-'
#define NGUID_VALUE_AUTO "auto"
#define NGUID_FMT \
"%02hhx%02hhx%02hhx%02hhx" \
"%02hhx%02hhx%02hhx%02hhx" \
"%02hhx%02hhx%02hhx%02hhx" \
"%02hhx%02hhx%02hhx%02hhx"
#define NGUID_STR_LEN (2 * NGUID_LEN + 1)
bool nvme_nguid_is_null(const NvmeNGUID *nguid)
{
static NvmeNGUID null_nguid;
return memcmp(nguid, &null_nguid, sizeof(NvmeNGUID)) == 0;
}
static void nvme_nguid_generate(NvmeNGUID *out)
{
int i;
uint32_t x;
QEMU_BUILD_BUG_ON((NGUID_LEN % sizeof(x)) != 0);
for (i = 0; i < NGUID_LEN; i += sizeof(x)) {
x = g_random_int();
memcpy(&out->data[i], &x, sizeof(x));
}
}
/*
* The Linux Kernel typically prints the NGUID of an NVMe namespace using the
* same format as the UUID. For instance:
*
* $ cat /sys/class/block/nvme0n1/nguid
* e9accd3b-8390-4e13-167c-f0593437f57d
*
* When there is no UUID but there is NGUID the Kernel will print the NGUID as
* wwid and it won't use the UUID format:
*
* $ cat /sys/class/block/nvme0n1/wwid
* eui.e9accd3b83904e13167cf0593437f57d
*
* The NGUID has different fields compared to the UUID, so the grouping used in
* the UUID format has no relation with the 3 fields of the NGUID.
*
* This implementation won't expect a strict format as the UUID one and instead
* it will admit any string of hexadecimal digits. Byte groups could be created
* using the '-' separator. The number of bytes needs to be exactly 16 and the
* separator '-' has to be exactly in a byte boundary. The following are
* examples of accepted formats for the NGUID string:
*
* nguid="e9accd3b-8390-4e13-167c-f0593437f57d"
* nguid="e9accd3b83904e13167cf0593437f57d"
* nguid="FEDCBA9876543210-ABCDEF-0123456789"
*/
static bool nvme_nguid_is_valid(const char *str)
{
int i;
int digit_count = 0;
for (i = 0; i < strlen(str); i++) {
const char c = str[i];
if (qemu_isxdigit(c)) {
digit_count++;
continue;
}
if (c == NGUID_SEPARATOR) {
/*
* We need to make sure the separator is in a byte boundary, the
* string does not start with the separator and they are not back to
* back "--".
*/
if ((i > 0) && (str[i - 1] != NGUID_SEPARATOR) &&
(digit_count % 2) == 0) {
continue;
}
}
return false;
}
/*
* The string should have the correct byte length and not finish with the
* separator
*/
return (digit_count == (2 * NGUID_LEN)) && (str[i - 1] != NGUID_SEPARATOR);
}
static int nvme_nguid_parse(const char *str, NvmeNGUID *nguid)
{
uint8_t *id = &nguid->data[0];
int ret = 0;
int i;
const char *ptr = str;
if (!nvme_nguid_is_valid(str)) {
return -1;
}
for (i = 0; i < NGUID_LEN; i++) {
ret = sscanf(ptr, "%02hhx", &id[i]);
if (ret != 1) {
return -1;
}
ptr += 2;
if (*ptr == NGUID_SEPARATOR) {
ptr++;
}
}
return 0;
}
/*
* When converted back to string this implementation will use a raw hex number
* with no separators, for instance:
*
* "e9accd3b83904e13167cf0593437f57d"
*/
static void nvme_nguid_stringify(const NvmeNGUID *nguid, char *out)
{
const uint8_t *id = &nguid->data[0];
snprintf(out, NGUID_STR_LEN, NGUID_FMT,
id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7],
id[8], id[9], id[10], id[11], id[12], id[13], id[14], id[15]);
}
static void get_nguid(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
const Property *prop = opaque;
NvmeNGUID *nguid = object_field_prop_ptr(obj, prop);
char buffer[NGUID_STR_LEN];
char *p = buffer;
nvme_nguid_stringify(nguid, buffer);
visit_type_str(v, name, &p, errp);
}
static void set_nguid(Object *obj, Visitor *v, const char *name, void *opaque,
Error **errp)
{
const Property *prop = opaque;
NvmeNGUID *nguid = object_field_prop_ptr(obj, prop);
char *str;
if (!visit_type_str(v, name, &str, errp)) {
return;
}
if (!strcmp(str, NGUID_VALUE_AUTO)) {
nvme_nguid_generate(nguid);
} else if (nvme_nguid_parse(str, nguid) < 0) {
error_set_from_qdev_prop_error(errp, EINVAL, obj, name, str);
}
g_free(str);
}
const PropertyInfo qdev_prop_nguid = {
.type = "str",
.description =
"NGUID or \"" NGUID_VALUE_AUTO "\" for random value",
.get = get_nguid,
.set = set_nguid,
};
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