1 /* 2 * Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan 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 typedef struct emem_storage{ 38 unsigned char *base; 39 size_t size; 40 size_t len; 41 unsigned char *ptr; 42 }emem_storage; 43 44 static ssize_t 45 emem_fetch(krb5_storage *sp, void *data, size_t size) 46 { 47 emem_storage *s = (emem_storage*)sp->data; 48 if((size_t)(s->base + s->len - s->ptr) < size) 49 size = s->base + s->len - s->ptr; 50 memmove(data, s->ptr, size); 51 sp->seek(sp, size, SEEK_CUR); 52 return size; 53 } 54 55 static ssize_t 56 emem_store(krb5_storage *sp, const void *data, size_t size) 57 { 58 emem_storage *s = (emem_storage*)sp->data; 59 if(size > (size_t)(s->base + s->size - s->ptr)){ 60 void *base; 61 size_t sz, off; 62 off = s->ptr - s->base; 63 sz = off + size; 64 if (sz < 4096) 65 sz *= 2; 66 base = realloc(s->base, sz); 67 if(base == NULL) 68 return -1; 69 s->size = sz; 70 s->base = base; 71 s->ptr = (unsigned char*)base + off; 72 } 73 memmove(s->ptr, data, size); 74 sp->seek(sp, size, SEEK_CUR); 75 return size; 76 } 77 78 static off_t 79 emem_seek(krb5_storage *sp, off_t offset, int whence) 80 { 81 emem_storage *s = (emem_storage*)sp->data; 82 switch(whence){ 83 case SEEK_SET: 84 if((size_t)offset > s->size) 85 offset = s->size; 86 if(offset < 0) 87 offset = 0; 88 s->ptr = s->base + offset; 89 if((size_t)offset > s->len) 90 s->len = offset; 91 break; 92 case SEEK_CUR: 93 sp->seek(sp,s->ptr - s->base + offset, SEEK_SET); 94 break; 95 case SEEK_END: 96 sp->seek(sp, s->len + offset, SEEK_SET); 97 break; 98 default: 99 errno = EINVAL; 100 return -1; 101 } 102 return s->ptr - s->base; 103 } 104 105 static int 106 emem_trunc(krb5_storage *sp, off_t offset) 107 { 108 emem_storage *s = (emem_storage*)sp->data; 109 /* 110 * If offset is larget then current size, or current size is 111 * shrunk more then half of the current size, adjust buffer. 112 */ 113 if (offset == 0) { 114 free(s->base); 115 s->size = 0; 116 s->base = NULL; 117 s->ptr = NULL; 118 } else if ((size_t)offset > s->size || (s->size / 2) > (size_t)offset) { 119 void *base; 120 size_t off; 121 off = s->ptr - s->base; 122 base = realloc(s->base, offset); 123 if(base == NULL) 124 return ENOMEM; 125 if ((size_t)offset > s->size) 126 memset((char *)base + s->size, 0, offset - s->size); 127 s->size = offset; 128 s->base = base; 129 s->ptr = (unsigned char *)base + off; 130 } 131 s->len = offset; 132 if ((s->ptr - s->base) > offset) 133 s->ptr = s->base + offset; 134 return 0; 135 } 136 137 138 static void 139 emem_free(krb5_storage *sp) 140 { 141 emem_storage *s = sp->data; 142 memset(s->base, 0, s->len); 143 free(s->base); 144 } 145 146 /** 147 * Create a elastic (allocating) memory storage backend. Memory is 148 * allocated on demand. Free returned krb5_storage with 149 * krb5_storage_free(). 150 * 151 * @return A krb5_storage on success, or NULL on out of memory error. 152 * 153 * @ingroup krb5_storage 154 * 155 * @sa krb5_storage_from_mem() 156 * @sa krb5_storage_from_readonly_mem() 157 * @sa krb5_storage_from_fd() 158 * @sa krb5_storage_from_data() 159 */ 160 161 KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL 162 krb5_storage_emem(void) 163 { 164 krb5_storage *sp; 165 emem_storage *s; 166 167 sp = malloc(sizeof(krb5_storage)); 168 if (sp == NULL) 169 return NULL; 170 171 s = malloc(sizeof(*s)); 172 if (s == NULL) { 173 free(sp); 174 return NULL; 175 } 176 sp->data = s; 177 sp->flags = 0; 178 sp->eof_code = HEIM_ERR_EOF; 179 s->size = 1024; 180 s->base = malloc(s->size); 181 if (s->base == NULL) { 182 free(sp); 183 free(s); 184 return NULL; 185 } 186 s->len = 0; 187 s->ptr = s->base; 188 sp->fetch = emem_fetch; 189 sp->store = emem_store; 190 sp->seek = emem_seek; 191 sp->trunc = emem_trunc; 192 sp->free = emem_free; 193 sp->max_alloc = UINT_MAX/8; 194 return sp; 195 } 196