xref: /freebsd/crypto/heimdal/lib/krb5/store_emem.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 
37 RCSID("$Id: store_emem.c,v 1.13 2002/10/21 15:36:23 joda Exp $");
38 
39 typedef struct emem_storage{
40     unsigned char *base;
41     size_t size;
42     size_t len;
43     unsigned char *ptr;
44 }emem_storage;
45 
46 static ssize_t
47 emem_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 
57 static ssize_t
58 emem_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 
80 static off_t
81 emem_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 
107 static void
108 emem_free(krb5_storage *sp)
109 {
110     emem_storage *s = sp->data;
111     memset(s->base, 0, s->len);
112     free(s->base);
113 }
114 
115 krb5_storage *
116 krb5_storage_emem(void)
117 {
118     krb5_storage *sp = malloc(sizeof(krb5_storage));
119     emem_storage *s = malloc(sizeof(*s));
120     sp->data = s;
121     sp->flags = 0;
122     sp->eof_code = HEIM_ERR_EOF;
123     s->size = 1024;
124     s->base = malloc(s->size);
125     s->len = 0;
126     s->ptr = s->base;
127     sp->fetch = emem_fetch;
128     sp->store = emem_store;
129     sp->seek = emem_seek;
130     sp->free = emem_free;
131     return sp;
132 }
133