qemu/util/id.c

69 lines
1.6 KiB
C

/*
* Dealing with identifiers
*
* Copyright (C) 2014 Red Hat, Inc.
*
* Authors:
* Markus Armbruster <armbru@redhat.com>,
*
* This work is licensed under the terms of the GNU LGPL, version 2.1
* or later. See the COPYING.LIB file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qemu/ctype.h"
#include "qemu/id.h"
bool id_wellformed(const char *id)
{
int i;
if (!qemu_isalpha(id[0])) {
return false;
}
for (i = 1; id[i]; i++) {
if (!qemu_isalnum(id[i]) && !strchr("-._", id[i])) {
return false;
}
}
return true;
}
#define ID_SPECIAL_CHAR '#'
static const char *const id_subsys_str[ID_MAX] = {
[ID_QDEV] = "qdev",
[ID_BLOCK] = "block",
[ID_CHR] = "chr",
};
/*
* Generates an ID of the form PREFIX SUBSYSTEM NUMBER
* where:
*
* - PREFIX is the reserved character '#'
* - SUBSYSTEM identifies the subsystem creating the ID
* - NUMBER is a decimal number unique within SUBSYSTEM.
*
* Example: "#block146"
*
* Note that these IDs do not satisfy id_wellformed().
*
* The caller is responsible for freeing the returned string with g_free()
*/
char *id_generate(IdSubSystems id)
{
static uint64_t id_counters[ID_MAX];
uint32_t rnd;
assert(id < ARRAY_SIZE(id_subsys_str));
assert(id_subsys_str[id]);
rnd = g_random_int_range(0, 100);
return g_strdup_printf("%c%s%" PRIu64 "%02" PRId32, ID_SPECIAL_CHAR,
id_subsys_str[id],
id_counters[id]++,
rnd);
}