1 /* mcookie.c -- Generates random numbers for xauth
2 * Created: Fri Feb 3 10:42:48 1995 by faith@cs.unc.edu
3 * Revised: Fri Mar 19 07:48:01 1999 by faith@acm.org
4 * Public Domain 1995, 1999 Rickard E. Faith (faith@acm.org)
5 * This program comes with ABSOLUTELY NO WARRANTY.
7 * This program gathers some random bits of data and used the MD5
8 * message-digest algorithm to generate a 128-bit hexadecimal number for
11 * NOTE: Unless /dev/random is available, this program does not actually
12 * gather 128 bits of random information, so the magic cookie generated
13 * will be considerably easier to guess than one might expect.
15 * 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
16 * - added Native Language Support
17 * 1999-03-21 aeb: Added some fragments of code from Colin Plumb.
32 #define BUFFERSIZE 4096
36 int minlength
, maxlength
;
38 {"/dev/random", 16, 16}, /* 16 bytes = 128 bits suffice */
39 {"/proc/interrupts", 0, 0},
40 {"/proc/slabinfo", 0, 0},
42 {"/dev/urandom", 32, 64},
45 #define RNGS (sizeof(rngs)/sizeof(struct rngs))
47 /* The basic function to hash a file */
48 static off_t
hash_file(struct MD5Context
*ctx
, int fd
)
52 unsigned char buf
[BUFFERSIZE
];
54 while ((r
= read(fd
, buf
, sizeof(buf
))) > 0) {
55 MD5Update(ctx
, buf
, r
);
58 /* Separate files with a null byte */
60 MD5Update(ctx
, buf
, 1);
64 static void __attribute__ ((__noreturn__
)) usage(FILE * out
)
66 fputs(_("\nUsage:\n"), out
);
68 _(" %s [options]\n"), program_invocation_short_name
);
70 fputs(_("\nOptions:\n"), out
);
71 fputs(_(" -f, --file <file> use file as a cookie seed\n"
72 " -v, --verbose explain what is being done\n"
73 " -V, --version output version information and exit\n"
74 " -h, --help display this help and exit\n\n"), out
);
76 exit(out
== stderr
? EXIT_FAILURE
: EXIT_SUCCESS
);
79 int main(int argc
, char **argv
)
82 struct MD5Context ctx
;
83 unsigned char digest
[MD5LENGTH
];
84 unsigned char buf
[BUFFERSIZE
];
94 static const struct option longopts
[] = {
95 {"file", required_argument
, NULL
, 'f'},
96 {"verbose", no_argument
, NULL
, 'v'},
97 {"version", no_argument
, NULL
, 'V'},
98 {"help", no_argument
, NULL
, 'h'},
102 setlocale(LC_ALL
, "");
103 bindtextdomain(PACKAGE
, LOCALEDIR
);
107 getopt_long(argc
, argv
, "f:vVh", longopts
, NULL
)) != -1)
116 printf(_("%s from %s\n"),
117 program_invocation_short_name
,
127 gettimeofday(&tv
, &tz
);
128 MD5Update(&ctx
, (unsigned char *) &tv
, sizeof(tv
));
131 MD5Update(&ctx
, (unsigned char *) &pid
, sizeof(pid
));
133 MD5Update(&ctx
, (unsigned char *) &pid
, sizeof(pid
));
138 if (file
[0] == '-' && !file
[1])
141 fd
= open(file
, O_RDONLY
);
144 warn(_("Could not open %s"), file
);
146 count
= hash_file(&ctx
, fd
);
149 _("Got %d bytes from %s\n"), count
,
152 if (fd
!= STDIN_FILENO
)
155 _("closing %s failed"), file
);
159 for (i
= 0; i
< RNGS
; i
++) {
160 if ((fd
= open(rngs
[i
].path
, O_RDONLY
| O_NONBLOCK
)) >= 0) {
161 int count
= sizeof(buf
);
163 if (rngs
[i
].maxlength
&& count
> rngs
[i
].maxlength
)
164 count
= rngs
[i
].maxlength
;
165 r
= read(fd
, buf
, count
);
167 MD5Update(&ctx
, buf
, r
);
173 _("Got %d bytes from %s\n"), r
,
175 if (rngs
[i
].minlength
&& r
>= rngs
[i
].minlength
)
178 warn(_("Could not open %s"), rngs
[i
].path
);
181 MD5Final(digest
, &ctx
);
182 for (i
= 0; i
< MD5LENGTH
; i
++)
183 printf("%02x", digest
[i
]);
187 * The following is important for cases like disk full,
188 * so shell scripts can bomb out properly rather than
189 * think they succeeded.
191 if (fflush(stdout
) < 0 || fclose(stdout
) < 0)