1/*	$OpenBSD: helper.c,v 1.18 2019/06/28 13:32:41 deraadt Exp $ */
2
3/*
4 * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19/*
20 * If we meet some day, and you think this stuff is worth it, you
21 * can buy me a beer in return. Poul-Henning Kamp
22 */
23
24#include <sys/types.h>
25#include <sys/stat.h>
26
27#include <errno.h>
28#include <fcntl.h>
29#include <stdlib.h>
30#include <stdio.h>
31#include <string.h>
32#include <unistd.h>
33
34#include <hashinc>
35
36#define MINIMUM(a, b)	(((a) < (b)) ? (a) : (b))
37
38char *
39HASHEnd(HASH_CTX *ctx, char *buf)
40{
41	int i;
42	u_int8_t digest[HASH_DIGEST_LENGTH];
43	static const char hex[] = "0123456789abcdef";
44
45	if (buf == NULL && (buf = malloc(HASH_DIGEST_STRING_LENGTH)) == NULL)
46		return (NULL);
47
48	HASHFinal(digest, ctx);
49	for (i = 0; i < HASH_DIGEST_LENGTH; i++) {
50		buf[i + i] = hex[digest[i] >> 4];
51		buf[i + i + 1] = hex[digest[i] & 0x0f];
52	}
53	buf[i + i] = '\0';
54	explicit_bzero(digest, sizeof(digest));
55	return (buf);
56}
57DEF_WEAK(HASHEnd);
58
59char *
60HASHFileChunk(const char *filename, char *buf, off_t off, off_t len)
61{
62	struct stat sb;
63	u_char buffer[BUFSIZ];
64	HASH_CTX ctx;
65	int fd, save_errno;
66	ssize_t nr;
67
68	HASHInit(&ctx);
69
70	if ((fd = open(filename, O_RDONLY)) == -1)
71		return (NULL);
72	if (len == 0) {
73		if (fstat(fd, &sb) == -1) {
74			save_errno = errno;
75			close(fd);
76			errno = save_errno;
77			return (NULL);
78		}
79		len = sb.st_size;
80	}
81	if (off > 0 && lseek(fd, off, SEEK_SET) == -1) {
82		save_errno = errno;
83		close(fd);
84		errno = save_errno;
85		return (NULL);
86	}
87
88	while ((nr = read(fd, buffer, MINIMUM(sizeof(buffer), len))) > 0) {
89		HASHUpdate(&ctx, buffer, nr);
90		if (len > 0 && (len -= nr) == 0)
91			break;
92	}
93
94	save_errno = errno;
95	close(fd);
96	errno = save_errno;
97	return (nr == -1 ? NULL : HASHEnd(&ctx, buf));
98}
99DEF_WEAK(HASHFileChunk);
100
101char *
102HASHFile(const char *filename, char *buf)
103{
104	return (HASHFileChunk(filename, buf, 0, 0));
105}
106DEF_WEAK(HASHFile);
107
108char *
109HASHData(const u_char *data, size_t len, char *buf)
110{
111	HASH_CTX ctx;
112
113	HASHInit(&ctx);
114	HASHUpdate(&ctx, data, len);
115	return (HASHEnd(&ctx, buf));
116}
117DEF_WEAK(HASHData);
118