1 /* $NetBSD: store_emem.c,v 1.1.1.2 2014/04/24 12:45:51 pettai Exp $ */
2
3 /*
4 * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include "krb5_locl.h"
37 #include "store-int.h"
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
emem_fetch(krb5_storage * sp,void * data,size_t size)47 emem_fetch(krb5_storage *sp, void *data, size_t size)
48 {
49 emem_storage *s = (emem_storage*)sp->data;
50 if((size_t)(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
emem_store(krb5_storage * sp,const void * data,size_t size)58 emem_store(krb5_storage *sp, const void *data, size_t size)
59 {
60 emem_storage *s = (emem_storage*)sp->data;
61 if(size > (size_t)(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 -1;
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
emem_seek(krb5_storage * sp,off_t offset,int whence)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((size_t)offset > s->size)
87 offset = s->size;
88 if(offset < 0)
89 offset = 0;
90 s->ptr = s->base + offset;
91 if((size_t)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 int
emem_trunc(krb5_storage * sp,off_t offset)108 emem_trunc(krb5_storage *sp, off_t offset)
109 {
110 emem_storage *s = (emem_storage*)sp->data;
111 /*
112 * If offset is larget then current size, or current size is
113 * shrunk more then half of the current size, adjust buffer.
114 */
115 if (offset == 0) {
116 free(s->base);
117 s->size = 0;
118 s->base = NULL;
119 s->ptr = NULL;
120 } else if ((size_t)offset > s->size || (s->size / 2) > (size_t)offset) {
121 void *base;
122 size_t off;
123 off = s->ptr - s->base;
124 base = realloc(s->base, offset);
125 if(base == NULL)
126 return ENOMEM;
127 if ((size_t)offset > s->size)
128 memset((char *)base + s->size, 0, offset - s->size);
129 s->size = offset;
130 s->base = base;
131 s->ptr = (unsigned char *)base + off;
132 }
133 s->len = offset;
134 if ((s->ptr - s->base) > offset)
135 s->ptr = s->base + offset;
136 return 0;
137 }
138
139
140 static void
emem_free(krb5_storage * sp)141 emem_free(krb5_storage *sp)
142 {
143 emem_storage *s = sp->data;
144 memset(s->base, 0, s->len);
145 free(s->base);
146 }
147
148 /**
149 * Create a elastic (allocating) memory storage backend. Memory is
150 * allocated on demand. Free returned krb5_storage with
151 * krb5_storage_free().
152 *
153 * @return A krb5_storage on success, or NULL on out of memory error.
154 *
155 * @ingroup krb5_storage
156 *
157 * @sa krb5_storage_from_mem()
158 * @sa krb5_storage_from_readonly_mem()
159 * @sa krb5_storage_from_fd()
160 * @sa krb5_storage_from_data()
161 */
162
163 KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL
krb5_storage_emem(void)164 krb5_storage_emem(void)
165 {
166 krb5_storage *sp;
167 emem_storage *s;
168
169 sp = malloc(sizeof(krb5_storage));
170 if (sp == NULL)
171 return NULL;
172
173 s = malloc(sizeof(*s));
174 if (s == NULL) {
175 free(sp);
176 return NULL;
177 }
178 sp->data = s;
179 sp->flags = 0;
180 sp->eof_code = HEIM_ERR_EOF;
181 s->size = 1024;
182 s->base = malloc(s->size);
183 if (s->base == NULL) {
184 free(sp);
185 free(s);
186 return NULL;
187 }
188 s->len = 0;
189 s->ptr = s->base;
190 sp->fetch = emem_fetch;
191 sp->store = emem_store;
192 sp->seek = emem_seek;
193 sp->trunc = emem_trunc;
194 sp->free = emem_free;
195 sp->max_alloc = UINT_MAX/8;
196 return sp;
197 }
198