crypto/dist/heimdal/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("$Heimdal: store_emem.c 21745 2007-07-31 16:11:25Z lha $"
  38         "$NetBSD$");
  39
  40 typedef struct emem_storage{
  41     unsigned char *base;
  42     size_t size;
  43     size_t len;
  44     unsigned char *ptr;
  45 }emem_storage;
  46
  47 static ssize_t
  48 emem_fetch(krb5_storage *sp, void *data, size_t size)
  49 {
  50     emem_storage *s = (emem_storage*)sp->data;
  51     if(s->base + s->len - s->ptr < size)
  52         size = s->base + s->len - s->ptr;
  53     memmove(data, s->ptr, size);
  54     sp->seek(sp, size, SEEK_CUR);
  55     return size;
  56 }
  57
  58 static ssize_t
  59 emem_store(krb5_storage *sp, const void *data, size_t size)
  60 {
  61     emem_storage *s = (emem_storage*)sp->data;
  62     if(size > s->base + s->size - s->ptr){
  63         void *base;
  64         size_t sz, off;
  65         off = s->ptr - s->base;
  66         sz = off + size;
  67         if (sz < 4096)
  68             sz *= 2;
  69         base = realloc(s->base, sz);
  70         if(base == NULL)
  71             return 0;
  72         s->size = sz;
  73         s->base = base;
  74         s->ptr = (unsigned char*)base + off;
  75     }
  76     memmove(s->ptr, data, size);
  77     sp->seek(sp, size, SEEK_CUR);
  78     return size;
  79 }
  80
  81 static off_t
  82 emem_seek(krb5_storage *sp, off_t offset, int whence)
  83 {
  84     emem_storage *s = (emem_storage*)sp->data;
  85     switch(whence){
  86     case SEEK_SET:
  87         if(offset > s->size)
  88             offset = s->size;
  89         if(offset < 0)
  90             offset = 0;
  91         s->ptr = s->base + offset;
  92         if(offset > s->len)
  93             s->len = offset;
  94         break;
  95     case SEEK_CUR:
  96         sp->seek(sp,s->ptr - s->base + offset, SEEK_SET);
  97         break;
  98     case SEEK_END:
  99         sp->seek(sp, s->len + offset, SEEK_SET);
 100         break;
 101     default:
 102         errno = EINVAL;
 103         return -1;
 104     }
 105     return s->ptr - s->base;
 106 }
 107
 108 static void
 109 emem_free(krb5_storage *sp)
 110 {
 111     emem_storage *s = sp->data;
 112     memset(s->base, 0, s->len);
 113     free(s->base);
 114 }
 115
 116 krb5_storage * KRB5_LIB_FUNCTION
 117 krb5_storage_emem(void)
 118 {
 119     krb5_storage *sp = malloc(sizeof(krb5_storage));
 120     if (sp == NULL)
 121         return NULL;
 122     emem_storage *s = malloc(sizeof(*s));
 123     if (s == NULL) {
 124         free(sp);
 125         return NULL;
 126     }
 127     sp->data = s;
 128     sp->flags = 0;
 129     sp->eof_code = HEIM_ERR_EOF;
 130     s->size = 1024;
 131     s->base = malloc(s->size);
 132     if (s->base == NULL) {
 133         free(sp);
 134         free(s);
 135         return NULL;
 136     }
 137     s->len = 0;
 138     s->ptr = s->base;
 139     sp->fetch = emem_fetch;
 140     sp->store = emem_store;
 141     sp->seek = emem_seek;
 142     sp->free = emem_free;
 143     return sp;
 144 }