balloon: Don't balloon roms
[qemu.git] / util / id.c
1 /*
2 * Dealing with identifiers
3 *
4 * Copyright (C) 2014 Red Hat, Inc.
5 *
6 * Authors:
7 * Markus Armbruster <armbru@redhat.com>,
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2.1
10 * or later. See the COPYING.LIB file in the top-level directory.
11 */
12
13 #include "qemu/osdep.h"
14 #include "qemu-common.h"
15 #include "qemu/id.h"
16
17 bool id_wellformed(const char *id)
18 {
19 int i;
20
21 if (!qemu_isalpha(id[0])) {
22 return false;
23 }
24 for (i = 1; id[i]; i++) {
25 if (!qemu_isalnum(id[i]) && !strchr("-._", id[i])) {
26 return false;
27 }
28 }
29 return true;
30 }
31
32 #define ID_SPECIAL_CHAR '#'
33
34 static const char *const id_subsys_str[ID_MAX] = {
35 [ID_QDEV] = "qdev",
36 [ID_BLOCK] = "block",
37 };
38
39 /*
40 * Generates an ID of the form PREFIX SUBSYSTEM NUMBER
41 * where:
42 *
43 * - PREFIX is the reserved character '#'
44 * - SUBSYSTEM identifies the subsystem creating the ID
45 * - NUMBER is a decimal number unique within SUBSYSTEM.
46 *
47 * Example: "#block146"
48 *
49 * Note that these IDs do not satisfy id_wellformed().
50 *
51 * The caller is responsible for freeing the returned string with g_free()
52 */
53 char *id_generate(IdSubSystems id)
54 {
55 static uint64_t id_counters[ID_MAX];
56 uint32_t rnd;
57
58 assert(id < ARRAY_SIZE(id_subsys_str));
59 assert(id_subsys_str[id]);
60
61 rnd = g_random_int_range(0, 100);
62
63 return g_strdup_printf("%c%s%" PRIu64 "%02" PRId32, ID_SPECIAL_CHAR,
64 id_subsys_str[id],
65 id_counters[id]++,
66 rnd);
67 }