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 36 RCSID("$Id: store_emem.c,v 1.11 2002/02/11 13:03:25 joda Exp $"); 37 38 typedef struct emem_storage{ 39 unsigned char *base; 40 size_t size; 41 size_t len; 42 unsigned char *ptr; 43 }emem_storage; 44 45 static ssize_t 46 emem_fetch(krb5_storage *sp, void *data, size_t size) 47 { 48 emem_storage *s = (emem_storage*)sp->data; 49 if(s->base + s->len - s->ptr < size) 50 size = s->base + s->len - s->ptr; 51 memmove(data, s->ptr, size); 52 sp->seek(sp, size, SEEK_CUR); 53 return size; 54 } 55 56 static ssize_t 57 emem_store(krb5_storage *sp, const void *data, size_t size) 58 { 59 emem_storage *s = (emem_storage*)sp->data; 60 if(size > s->base + s->size - s->ptr){ 61 void *base; 62 size_t sz, off; 63 sz = 2 * (size + (s->ptr - s->base)); /* XXX */ 64 off = s->ptr - s->base; 65 base = realloc(s->base, sz); 66 if(base == NULL) 67 return 0; 68 s->size = sz; 69 s->base = base; 70 s->ptr = (unsigned char*)base + off; 71 } 72 memmove(s->ptr, data, size); 73 sp->seek(sp, size, SEEK_CUR); 74 return size; 75 } 76 77 static off_t 78 emem_seek(krb5_storage *sp, off_t offset, int whence) 79 { 80 emem_storage *s = (emem_storage*)sp->data; 81 switch(whence){ 82 case SEEK_SET: 83 if(offset > s->size) 84 offset = s->size; 85 if(offset < 0) 86 offset = 0; 87 s->ptr = s->base + offset; 88 if(offset > s->len) 89 s->len = offset; 90 break; 91 case SEEK_CUR: 92 sp->seek(sp,s->ptr - s->base + offset, SEEK_SET); 93 break; 94 case SEEK_END: 95 sp->seek(sp, s->len + offset, SEEK_SET); 96 break; 97 default: 98 errno = EINVAL; 99 return -1; 100 } 101 return s->ptr - s->base; 102 } 103 104 static void 105 emem_free(krb5_storage *sp) 106 { 107 emem_storage *s = sp->data; 108 memset(s->base, 0, s->len); 109 free(s->base); 110 } 111 112 krb5_storage * 113 krb5_storage_emem(void) 114 { 115 krb5_storage *sp = malloc(sizeof(krb5_storage)); 116 emem_storage *s = malloc(sizeof(*s)); 117 sp->data = s; 118 sp->flags = 0; 119 s->size = 1024; 120 s->base = malloc(s->size); 121 s->len = 0; 122 s->ptr = s->base; 123 sp->fetch = emem_fetch; 124 sp->store = emem_store; 125 sp->seek = emem_seek; 126 sp->free = emem_free; 127 return sp; 128 } 129