LXR qemu/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/ctype.h"
  15#include "qemu/id.h"
  16
  17bool 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
  34static const char *const id_subsys_str[ID_MAX] = {
  35    [ID_QDEV]  = "qdev",
  36    [ID_BLOCK] = "block",
  37    [ID_CHR] = "chr",
  38    [ID_NET] = "net",
  39};
  40
  41/*
  42 *  Generates an ID of the form PREFIX SUBSYSTEM NUMBER
  43 *  where:
  44 *
  45 *  - PREFIX is the reserved character '#'
  46 *  - SUBSYSTEM identifies the subsystem creating the ID
  47 *  - NUMBER is a decimal number unique within SUBSYSTEM.
  48 *
  49 *    Example: "#block146"
  50 *
  51 * Note that these IDs do not satisfy id_wellformed().
  52 *
  53 * The caller is responsible for freeing the returned string with g_free()
  54 */
  55char *id_generate(IdSubSystems id)
  56{
  57    static uint64_t id_counters[ID_MAX];
  58    uint32_t rnd;
  59
  60    assert(id < ARRAY_SIZE(id_subsys_str));
  61    assert(id_subsys_str[id]);
  62
  63    rnd = g_random_int_range(0, 100);
  64
  65    return g_strdup_printf("%c%s%" PRIu64 "%02" PRId32, ID_SPECIAL_CHAR,
  66                                                        id_subsys_str[id],
  67                                                        id_counters[id]++,
  68                                                        rnd);
  69}
  70