crypto/external/bsd/heimdal/dist/lib/krb5/store_emem.c

   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
  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
  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
  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
 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
 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
 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 }