lib/libstand/uuid_to_string.c

   1 /*-
   2  * Copyright (c) 2015 M. Warner Losh
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: head/lib/libstand/uuid_to_string.c 293468 2016-01-09 08:04:29Z ae $
  27  */
  28
  29
  30 /*
  31  * Note: some comments taken from lib/libc/uuid/uuid_to_string.c
  32  * Copyright (c) 2002,2005 Marcel Moolenaar
  33  * Copyright (c) 2002 Hiten Mahesh Pandya
  34  */
  35
  36 #include <stand.h>
  37 #include <uuid.h>
  38
  39 /*
  40  * Dump len characters into *buf from val as hex and update *buf
  41  */
  42 static void
  43 tohex(char **buf, int len, uint32_t val)
  44 {
  45         static const char *hexstr = "0123456789abcdef";
  46         char *walker = *buf;
  47         int i;
  48
  49         for (i = len - 1; i >= 0; i--) {
  50                 walker[i] = hexstr[val & 0xf];
  51                 val >>= 4;
  52         }
  53         *buf = walker + len;
  54 }
  55
  56 /*
  57  * uuid_to_string() - Convert a binary UUID into a string representation.
  58  * See also:
  59  *      http://www.opengroup.org/onlinepubs/009629399/uuid_to_string.htm
  60  *
  61  * NOTE: The references given above do not have a status code for when
  62  *       the string could not be allocated. The status code has been
  63  *       taken from the Hewlett-Packard implementation.
  64  *
  65  * NOTE: we don't support u == NULL for a nil UUID, sorry.
  66  *
  67  * NOTE: The sequence field is in big-endian, while the time fields are in
  68  *       native byte order.
  69  *
  70  *       hhhhhhhh-hhhh-hhhh-bbbb-bbbbbbbbbbbb
  71  *       01234567-89ab-cdef-0123-456789abcdef
  72  */
  73 void
  74 uuid_to_string(const uuid_t *u, char **s, uint32_t *status)
  75 {
  76         uuid_t nil;
  77         char *w;
  78
  79         if (status != NULL)
  80                 *status = uuid_s_ok;
  81         if (s == NULL)  /* Regular version does this odd-ball behavior too */
  82                 return;
  83         w = *s = malloc(37);
  84         if (*s == NULL) {
  85                 if (status != NULL)
  86                         *status = uuid_s_no_memory;
  87                 return;
  88         }
  89         if (u == NULL) {
  90                 u = &nil;
  91                 uuid_create_nil(&nil, NULL);
  92         }
  93         /* native */
  94         tohex(&w, 8, u->time_low);
  95         *w++ = '-';
  96         tohex(&w, 4, u->time_mid);
  97         *w++ = '-';
  98         tohex(&w, 4, u->time_hi_and_version);
  99         *w++ = '-';
 100         /* Big endian, so do a byte at a time */
 101         tohex(&w, 2, u->clock_seq_hi_and_reserved);
 102         tohex(&w, 2, u->clock_seq_low);
 103         *w++ = '-';
 104         tohex(&w, 2, u->node[0]);
 105         tohex(&w, 2, u->node[1]);
 106         tohex(&w, 2, u->node[2]);
 107         tohex(&w, 2, u->node[3]);
 108         tohex(&w, 2, u->node[4]);
 109         tohex(&w, 2, u->node[5]);
 110         *w++ = '\0';
 111 }