qemu

FORK: QEMU emulator
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id.c (1684B)

      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 
     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     [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  */
     55 char *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 }