mpiutil.c

  1/* mpiutil.ac  -  Utility functions for MPI
  2 * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
  3 *
  4 * This file is part of GnuPG.
  5 *
  6 * GnuPG is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License as published by
  8 * the Free Software Foundation; either version 2 of the License, or
  9 * (at your option) any later version.
 10 *
 11 * GnuPG is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14 * GNU General Public License for more details.
 15 *
 16 * You should have received a copy of the GNU General Public License
 17 * along with this program; if not, write to the Free Software
 18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 19 */
 20
 21#include <linux/export.h>
 22
 23#include "mpi-internal.h"
 24
 25/****************
 26 * Note:  It was a bad idea to use the number of limbs to allocate
 27 *	  because on a alpha the limbs are large but we normally need
 28 *	  integers of n bits - So we should change this to bits (or bytes).
 29 *
 30 *	  But mpi_alloc is used in a lot of places :-)
 31 */
 32MPI mpi_alloc(unsigned nlimbs)
 33{
 34	MPI a;
 35
 36	a = kmalloc(sizeof *a, GFP_KERNEL);
 37	if (!a)
 38		return a;
 39
 40	if (nlimbs) {
 41		a->d = mpi_alloc_limb_space(nlimbs);
 42		if (!a->d) {
 43			kfree(a);
 44			return NULL;
 45		}
 46	} else {
 47		a->d = NULL;
 48	}
 49
 50	a->alloced = nlimbs;
 51	a->nlimbs = 0;
 52	a->sign = 0;
 53	a->flags = 0;
 54	a->nbits = 0;
 55	return a;
 56}
 57EXPORT_SYMBOL_GPL(mpi_alloc);
 58
 59mpi_ptr_t mpi_alloc_limb_space(unsigned nlimbs)
 60{
 61	size_t len = nlimbs * sizeof(mpi_limb_t);
 62
 63	if (!len)
 64		return NULL;
 65
 66	return kmalloc(len, GFP_KERNEL);
 67}
 68
 69void mpi_free_limb_space(mpi_ptr_t a)
 70{
 71	if (!a)
 72		return;
 73
 74	kfree_sensitive(a);
 75}
 76
 77void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
 78{
 79	mpi_free_limb_space(a->d);
 80	a->d = ap;
 81	a->alloced = nlimbs;
 82}
 83
 84/****************
 85 * Resize the array of A to NLIMBS. the additional space is cleared
 86 * (set to 0) [done by m_realloc()]
 87 */
 88int mpi_resize(MPI a, unsigned nlimbs)
 89{
 90	void *p;
 91
 92	if (nlimbs <= a->alloced)
 93		return 0;	/* no need to do it */
 94
 95	if (a->d) {
 96		p = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
 97		if (!p)
 98			return -ENOMEM;
 99		memcpy(p, a->d, a->alloced * sizeof(mpi_limb_t));
100		kfree_sensitive(a->d);
101		a->d = p;
102	} else {
103		a->d = kcalloc(nlimbs, sizeof(mpi_limb_t), GFP_KERNEL);
104		if (!a->d)
105			return -ENOMEM;
106	}
107	a->alloced = nlimbs;
108	return 0;
109}
110
111void mpi_free(MPI a)
112{
113	if (!a)
114		return;
115
116	if (a->flags & 4)
117		kfree_sensitive(a->d);
118	else
119		mpi_free_limb_space(a->d);
120
121	if (a->flags & ~7)
122		pr_info("invalid flag value in mpi\n");
123	kfree(a);
124}
125EXPORT_SYMBOL_GPL(mpi_free);
126
127/****************
128 * Note: This copy function should not interpret the MPI
129 *	 but copy it transparently.
130 */
131MPI mpi_copy(MPI a)
132{
133	int i;
134	MPI b;
135
136	if (a) {
137		b = mpi_alloc(a->nlimbs);
138		if (!b)
139			return NULL;
140		b->nlimbs = a->nlimbs;
141		b->sign = a->sign;
142		b->flags = a->flags;
143		b->flags &= ~(16|32); /* Reset the immutable and constant flags. */
144		for (i = 0; i < b->nlimbs; i++)
145			b->d[i] = a->d[i];
146	} else
147		b = NULL;
148	return b;
149}
150
151MODULE_DESCRIPTION("Multiprecision maths library");
152MODULE_LICENSE("GPL");