1/*
2 * Copyright (c) 1997 - 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_emem.c 21745 2007-07-31 16:11:25Z lha $");
38
39typedef struct emem_storage{
40    unsigned char *base;
41    size_t size;
42    size_t len;
43    unsigned char *ptr;
44}emem_storage;
45
46static ssize_t
47emem_fetch(krb5_storage *sp, void *data, size_t size)
48{
49    emem_storage *s = (emem_storage*)sp->data;
50    if(s->base + s->len - s->ptr < size)
51	size = s->base + s->len - s->ptr;
52    memmove(data, s->ptr, size);
53    sp->seek(sp, size, SEEK_CUR);
54    return size;
55}
56
57static ssize_t
58emem_store(krb5_storage *sp, const void *data, size_t size)
59{
60    emem_storage *s = (emem_storage*)sp->data;
61    if(size > s->base + s->size - s->ptr){
62	void *base;
63	size_t sz, off;
64	off = s->ptr - s->base;
65	sz = off + size;
66	if (sz < 4096)
67	    sz *= 2;
68	base = realloc(s->base, sz);
69	if(base == NULL)
70	    return 0;
71	s->size = sz;
72	s->base = base;
73	s->ptr = (unsigned char*)base + off;
74    }
75    memmove(s->ptr, data, size);
76    sp->seek(sp, size, SEEK_CUR);
77    return size;
78}
79
80static off_t
81emem_seek(krb5_storage *sp, off_t offset, int whence)
82{
83    emem_storage *s = (emem_storage*)sp->data;
84    switch(whence){
85    case SEEK_SET:
86	if(offset > s->size)
87	    offset = s->size;
88	if(offset < 0)
89	    offset = 0;
90	s->ptr = s->base + offset;
91	if(offset > s->len)
92	    s->len = offset;
93	break;
94    case SEEK_CUR:
95	sp->seek(sp,s->ptr - s->base + offset, SEEK_SET);
96	break;
97    case SEEK_END:
98	sp->seek(sp, s->len + offset, SEEK_SET);
99	break;
100    default:
101	errno = EINVAL;
102	return -1;
103    }
104    return s->ptr - s->base;
105}
106
107static void
108emem_free(krb5_storage *sp)
109{
110    emem_storage *s = sp->data;
111    memset(s->base, 0, s->len);
112    free(s->base);
113}
114
115krb5_storage * KRB5_LIB_FUNCTION
116krb5_storage_emem(void)
117{
118    krb5_storage *sp = malloc(sizeof(krb5_storage));
119    if (sp == NULL)
120	return NULL;
121    emem_storage *s = malloc(sizeof(*s));
122    if (s == NULL) {
123	free(sp);
124	return NULL;
125    }
126    sp->data = s;
127    sp->flags = 0;
128    sp->eof_code = HEIM_ERR_EOF;
129    s->size = 1024;
130    s->base = malloc(s->size);
131    if (s->base == NULL) {
132	free(sp);
133	free(s);
134	return NULL;
135    }
136    s->len = 0;
137    s->ptr = s->base;
138    sp->fetch = emem_fetch;
139    sp->store = emem_store;
140    sp->seek = emem_seek;
141    sp->free = emem_free;
142    return sp;
143}
144