#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((size_t)(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 > (size_t)(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((size_t)offset > s->size)
offset = s->size;
if(offset < 0)
offset = 0;
s->ptr = s->base + offset;
if((size_t)offset > s->len)
s->len = (size_t)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 == 0) {
free(s->base);
s->size = 0;
s->base = NULL;
s->ptr = NULL;
} else if ((size_t)offset > s->size || (s->size / 2) > (size_t)offset) {
void *base;
size_t off;
size_t soffset = (size_t)offset;
off = s->ptr - s->base;
if (offset > (off_t)soffset)
return ENOMEM;
base = realloc(s->base, soffset);
if(base == NULL)
return ENOMEM;
if (soffset > s->size)
memset((char *)base + s->size, 0, soffset - s->size);
s->size = soffset;
s->base = base;
s->ptr = (unsigned char *)base + off;
}
s->len = (size_t)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);
}
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;
sp->max_alloc = UINT_MAX/8;
return sp;
}