1 /* Copyright (c) 2015, Google Inc.
2 *
3 * Permission to use, copy, modify, and/or distribute this software for any
4 * purpose with or without fee is hereby granted, provided that the above
5 * copyright notice and this permission notice appear in all copies.
6 *
7 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
8 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
10 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
12 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
13 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
14
15 #include <string>
16 #include <vector>
17
18 #include <stdint.h>
19 #include <stdlib.h>
20
21 #include <openssl/rand.h>
22
23 #include "internal.h"
24
25
26 static const struct argument kArguments[] = {
27 {
28 "-hex", kBooleanArgument,
29 "Hex encoded output."
30 },
31 {
32 "", kOptionalArgument, "",
33 },
34 };
35
Rand(const std::vector<std::string> & args)36 bool Rand(const std::vector<std::string> &args) {
37 bool forever = true, hex = false;
38 size_t len = 0;
39
40 if (!args.empty()) {
41 std::vector<std::string> args_copy(args);
42 const std::string &last_arg = args.back();
43
44 if (last_arg.size() > 0 && last_arg[0] != '-') {
45 char *endptr;
46 unsigned long long num = strtoull(last_arg.c_str(), &endptr, 10);
47 if (*endptr == 0) {
48 len = num;
49 forever = false;
50 args_copy.pop_back();
51 }
52 }
53
54 std::map<std::string, std::string> args_map;
55 if (!ParseKeyValueArguments(&args_map, args_copy, kArguments)) {
56 PrintUsage(kArguments);
57 return false;
58 }
59
60 hex = args_map.count("-hex") > 0;
61 }
62
63 uint8_t buf[4096];
64 uint8_t hex_buf[8192];
65
66 size_t done = 0;
67 while (forever || done < len) {
68 size_t todo = sizeof(buf);
69 if (!forever && todo > len - done) {
70 todo = len - done;
71 }
72 RAND_bytes(buf, todo);
73 if (hex) {
74 static const char hextable[] = "0123456789abdef";
75 for (unsigned i = 0; i < todo; i++) {
76 hex_buf[i*2] = hextable[buf[i] >> 4];
77 hex_buf[i*2 + 1] = hextable[buf[i] & 0xf];
78 }
79 if (fwrite(hex_buf, todo*2, 1, stdout) != 1) {
80 return false;
81 }
82 } else {
83 if (fwrite(buf, todo, 1, stdout) != 1) {
84 return false;
85 }
86 }
87 done += todo;
88 }
89
90 if (hex && fwrite("\n", 1, 1, stdout) != 1) {
91 return false;
92 }
93
94 return true;
95 }
96