lib/krb5/store_emem.c

   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 RCSID("$Id$");
  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 * KRB5_LIB_FUNCTION
 116 krb5_storage_emem(void)
 117 {
 118     krb5_storage *sp = malloc(sizeof(krb5_storage));
 119     if (sp == NULL)
 120         return NULL;
 121     emem_storage *s = malloc(sizeof(*s));
 122     if (s == NULL) {
 123         free(sp);
 124         return NULL;
 125     }
 126     sp->data = s;
 127     sp->flags = 0;
 128     sp->eof_code = HEIM_ERR_EOF;
 129     s->size = 1024;
 130     s->base = malloc(s->size);
 131     if (s->base == NULL) {
 132         free(sp);
 133         free(s);
 134         return NULL;
 135     }
 136     s->len = 0;
 137     s->ptr = s->base;
 138     sp->fetch = emem_fetch;
 139     sp->store = emem_store;
 140     sp->seek = emem_seek;
 141     sp->free = emem_free;
 142     return sp;
 143 }