1 /* md5wrap.cc: wrapper functions to allow easy use of MD5 from C++.
2 *
3 * Copyright (C) 2006,2010,2012,2015 Olly Betts
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19
20 #include <config.h>
21
22 #ifdef HAVE_POSIX_FADVISE
23 # ifdef __linux__
24 # define _POSIX_C_SOURCE 200112L // for posix_fadvise from fcntl.h
25 # define _DEFAULT_SOURCE 1 // Needed to get lstat() for glibc >= 2.20
26 # define _BSD_SOURCE 1 // Needed to get lstat() for glibc < 2.20
27 # endif
28 #endif
29
30 #include <string>
31
32 #include "safefcntl.h"
33 #include "safeerrno.h"
34 #include "safeunistd.h"
35
36 #include "md5.h"
37 #include "md5wrap.h"
38
39 using namespace std;
40
41 bool
md5_file(const string & file_name,string & md5,bool try_noatime)42 md5_file(const string &file_name, string &md5, bool try_noatime)
43 {
44 mode_t mode = O_RDONLY;
45 #if defined O_NOATIME && O_NOATIME != 0
46 if (try_noatime) mode |= O_NOATIME;
47 #else
48 (void)try_noatime;
49 #endif
50
51 int fd = open(file_name.c_str(), mode);
52 #if defined O_NOATIME && O_NOATIME != 0
53 if (fd < 0 && (mode & O_NOATIME)) {
54 mode &= ~O_NOATIME;
55 fd = open(file_name.c_str(), mode);
56 }
57 #endif
58 if (fd < 0) return false;
59
60 #ifdef HAVE_POSIX_FADVISE
61 posix_fadvise(fd, 0, 0, POSIX_FADV_NOREUSE); // or POSIX_FADV_SEQUENTIAL
62 #endif
63
64 MD5Context md5_ctx;
65 MD5Init(&md5_ctx);
66
67 unsigned char blk[4096];
68
69 while (true) {
70 int c = read(fd, blk, sizeof(blk));
71 if (c == 0) break;
72 if (c < 0) {
73 if (errno == EINTR) continue;
74 close(fd);
75 return false;
76 }
77 MD5Update(&md5_ctx, blk, c);
78 }
79
80 #ifdef HAVE_POSIX_FADVISE
81 posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
82 #endif
83
84 close(fd);
85
86 MD5Final(blk, &md5_ctx);
87 md5.assign(reinterpret_cast<const char *>(blk), 16);
88
89 return true;
90 }
91
92 void
md5_string(const string & str,string & md5)93 md5_string(const string &str, string &md5)
94 {
95 unsigned char blk[16];
96 MD5Context md5_ctx;
97
98 MD5Init(&md5_ctx);
99 MD5Update(&md5_ctx, reinterpret_cast<const unsigned char *>(str.data()),
100 str.size());
101 MD5Final(blk, &md5_ctx);
102 md5.assign(reinterpret_cast<const char *>(blk), 16);
103 }
104