store_mem.c revision 102644 
1/*
2 * Copyright (c) 1997 - 2000, 2002 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "krb5_locl.h"
35#include "store-int.h"
36
37RCSID("$Id: store_mem.c,v 1.11 2002/04/18 14:00:44 joda Exp $");
38
39typedef struct mem_storage{
40    unsigned char *base;
41    size_t size;
42    unsigned char *ptr;
43}mem_storage;
44
45static ssize_t
46mem_fetch(krb5_storage *sp, void *data, size_t size)
47{
48    mem_storage *s = (mem_storage*)sp->data;
49    if(size > s->base + s->size - s->ptr)
50	size = s->base + s->size - s->ptr;
51    memmove(data, s->ptr, size);
52    sp->seek(sp, size, SEEK_CUR);
53    return size;
54}
55
56static ssize_t
57mem_store(krb5_storage *sp, const void *data, size_t size)
58{
59    mem_storage *s = (mem_storage*)sp->data;
60    if(size > s->base + s->size - s->ptr)
61	size = s->base + s->size - s->ptr;
62    memmove(s->ptr, data, size);
63    sp->seek(sp, size, SEEK_CUR);
64    return size;
65}
66
67static off_t
68mem_seek(krb5_storage *sp, off_t offset, int whence)
69{
70    mem_storage *s = (mem_storage*)sp->data;
71    switch(whence){
72    case SEEK_SET:
73	if(offset > s->size)
74	    offset = s->size;
75	if(offset < 0)
76	    offset = 0;
77	s->ptr = s->base + offset;
78	break;
79    case SEEK_CUR:
80	return sp->seek(sp, s->ptr - s->base + offset, SEEK_SET);
81    case SEEK_END:
82	return sp->seek(sp, s->size + offset, SEEK_SET);
83    default:
84	errno = EINVAL;
85	return -1;
86    }
87    return s->ptr - s->base;
88}
89
90krb5_storage *
91krb5_storage_from_mem(void *buf, size_t len)
92{
93    krb5_storage *sp = malloc(sizeof(krb5_storage));
94    mem_storage *s;
95    if(sp == NULL)
96	return NULL;
97    s = malloc(sizeof(*s));
98    if(s == NULL) {
99	free(sp);
100	return NULL;
101    }
102    sp->data = s;
103    sp->flags = 0;
104    sp->eof_code = HEIM_ERR_EOF;
105    s->base = buf;
106    s->size = len;
107    s->ptr = buf;
108    sp->fetch = mem_fetch;
109    sp->store = mem_store;
110    sp->seek = mem_seek;
111    sp->free = NULL;
112    return sp;
113}
114
115krb5_storage *
116krb5_storage_from_data(krb5_data *data)
117{
118	return krb5_storage_from_mem(data->data, data->length);
119}
120