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(objp: 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(objp: a);
75}
76
77void mpi_assign_limb_space(MPI a, mpi_ptr_t ap, unsigned nlimbs)
78{
79 mpi_free_limb_space(a: 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(to: p, from: a->d, len: a->alloced * sizeof(mpi_limb_t));
100 kfree_sensitive(objp: 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(objp: a->d);
118 else
119 mpi_free_limb_space(a: a->d);
120
121 if (a->flags & ~7)
122 pr_info("invalid flag value in mpi\n");
123 kfree(objp: 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");
153