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/*
* Copyright (c) 1997 - 2002 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "krb5_locl.h"
#include "store-int.h"
typedef struct emem_storage{
unsigned char *base;
size_t size;
size_t len;
unsigned char *ptr;
}emem_storage;
static ssize_t
emem_fetch(krb5_storage *sp, void *data, size_t size)
{
emem_storage *s = (emem_storage*)sp->data;
if(s->base + s->len - s->ptr < size)
size = s->base + s->len - s->ptr;
memmove(data, s->ptr, size);
sp->seek(sp, size, SEEK_CUR);
return size;
}
static ssize_t
emem_store(krb5_storage *sp, const void *data, size_t size)
{
emem_storage *s = (emem_storage*)sp->data;
if(size > s->base + s->size - s->ptr){
void *base;
size_t sz, off;
off = s->ptr - s->base;
sz = off + size;
if (sz < 4096)
sz *= 2;
base = realloc(s->base, sz);
if(base == NULL)
return -1;
s->size = sz;
s->base = base;
s->ptr = (unsigned char*)base + off;
}
memmove(s->ptr, data, size);
sp->seek(sp, size, SEEK_CUR);
return size;
}
static off_t
emem_seek(krb5_storage *sp, off_t offset, int whence)
{
emem_storage *s = (emem_storage*)sp->data;
switch(whence){
case SEEK_SET:
if(offset > s->size)
offset = s->size;
if(offset < 0)
offset = 0;
s->ptr = s->base + offset;
if(offset > s->len)
s->len = offset;
break;
case SEEK_CUR:
sp->seek(sp,s->ptr - s->base + offset, SEEK_SET);
break;
case SEEK_END:
sp->seek(sp, s->len + offset, SEEK_SET);
break;
default:
errno = EINVAL;
return -1;
}
return s->ptr - s->base;
}
static int
emem_trunc(krb5_storage *sp, off_t offset)
{
emem_storage *s = (emem_storage*)sp->data;
/*
* If offset is larget then current size, or current size is
* shrunk more then half of the current size, adjust buffer.
*/
if (offset == 0) {
free(s->base);
s->size = 0;
s->base = NULL;
s->ptr = NULL;
} else if (offset > s->size || (s->size / 2) > offset) {
void *base;
size_t off;
off = s->ptr - s->base;
base = realloc(s->base, offset);
if(base == NULL)
return ENOMEM;
if (offset > s->size)
memset((char *)base + s->size, 0, offset - s->size);
s->size = offset;
s->base = base;
s->ptr = (unsigned char *)base + off;
}
s->len = offset;
if ((s->ptr - s->base) > offset)
s->ptr = s->base + offset;
return 0;
}
static void
emem_free(krb5_storage *sp)
{
emem_storage *s = sp->data;
memset(s->base, 0, s->len);
free(s->base);
}
/**
* Create a elastic (allocating) memory storage backend. Memory is
* allocated on demand. Free returned krb5_storage with
* krb5_storage_free().
*
* @return A krb5_storage on success, or NULL on out of memory error.
*
* @ingroup krb5_storage
*
* @sa krb5_storage_from_mem()
* @sa krb5_storage_from_readonly_mem()
* @sa krb5_storage_from_fd()
* @sa krb5_storage_from_data()
*/
KRB5_LIB_FUNCTION krb5_storage * KRB5_LIB_CALL
krb5_storage_emem(void)
{
krb5_storage *sp;
emem_storage *s;
sp = malloc(sizeof(krb5_storage));
if (sp == NULL)
return NULL;
s = malloc(sizeof(*s));
if (s == NULL) {
free(sp);
return NULL;
}
sp->data = s;
sp->flags = 0;
sp->eof_code = HEIM_ERR_EOF;
s->size = 1024;
s->base = malloc(s->size);
if (s->base == NULL) {
free(sp);
free(s);
return NULL;
}
s->len = 0;
s->ptr = s->base;
sp->fetch = emem_fetch;
sp->store = emem_store;
sp->seek = emem_seek;
sp->trunc = emem_trunc;
sp->free = emem_free;
return sp;
}
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