Botan: src/entropy/unix_procs/es_unix.cpp Source File

Botan 1.10.16

es_unix.cpp
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1 /*
2 * Unix EntropySource
3 * (C) 1999-2009 Jack Lloyd
4 *
5 * Distributed under the terms of the Botan license
6 */
7
8 #include <botan/internal/es_unix.h>
9 #include <botan/internal/unix_cmd.h>
10 #include <botan/parsing.h>
11 #include <algorithm>
12
13 #include <sys/time.h>
14 #include <sys/stat.h>
15 #include <sys/resource.h>
16 #include <unistd.h>
17
18 namespace Botan {
19
20 namespace {
21
22 /**
23 * Sort ordering by priority
24 */
25 bool Unix_Program_Cmp(const Unix_Program& a, const Unix_Program& b)
26 {
27 if(a.priority == b.priority)
28 return (a.name_and_args < b.name_and_args);
29
30 return (a.priority < b.priority);
31 }
32
33 }
34
35 /**
36 * Unix_EntropySource Constructor
37 */
38 Unix_EntropySource::Unix_EntropySource(const std::vector<std::string>& path) :
39 PATH(path)
40 {
41 std::vector<Unix_Program> default_sources = get_default_sources();
42 add_sources(&default_sources[0], default_sources.size());
43 }
44
45 /**
46 * Add sources to the list
47 */
48 void Unix_EntropySource::add_sources(const Unix_Program srcs[], size_t count)
49 {
50 sources.insert(sources.end(), srcs, srcs + count);
51 std::sort(sources.begin(), sources.end(), Unix_Program_Cmp);
52 }
53
54 /**
55 * Poll for entropy on a generic Unix system, first by grabbing various
56 * statistics (stat on common files, getrusage, etc), and then, if more
57 * is required, by exec'ing various programs like uname and rpcinfo and
58 * reading the output.
59 */
60 void Unix_EntropySource::poll(Entropy_Accumulator& accum)
61 {
62 const char* stat_targets[] = {
63 "/",
64 "/tmp",
65 "/var/tmp",
66 "/usr",
67 "/home",
68 "/etc/passwd",
69 ".",
70 "..",
71 0 };
72
73 for(size_t i = 0; stat_targets[i]; i++)
74 {
75 struct stat statbuf;
76 clear_mem(&statbuf, 1);
77 if(::stat(stat_targets[i], &statbuf) == 0)
78 accum.add(&statbuf, sizeof(statbuf), .005);
79 }
80
81 accum.add(::getpid(), 0);
82 accum.add(::getppid(), 0);
83 accum.add(::getuid(), 0);
84 accum.add(::getgid(), 0);
85 accum.add(::getpgrp(), 0);
86
87 struct ::rusage usage;
88 ::getrusage(RUSAGE_SELF, &usage);
89 accum.add(usage, .005);
90
91 ::getrusage(RUSAGE_CHILDREN, &usage);
92 accum.add(usage, .005);
93
94 const size_t MINIMAL_WORKING = 16;
95
96 MemoryRegion<byte>& io_buffer = accum.get_io_buffer(DEFAULT_BUFFERSIZE);
97
98 for(size_t i = 0; i != sources.size(); i++)
99 {
100 DataSource_Command pipe(sources[i].name_and_args, PATH);
101
102 size_t got_from_src = 0;
103
104 while(!pipe.end_of_data())
105 {
106 size_t got_this_loop = pipe.read(&io_buffer[0], io_buffer.size());
107 got_from_src += got_this_loop;
108
109 accum.add(&io_buffer[0], got_this_loop, .005);
110 }
111
112 sources[i].working = (got_from_src >= MINIMAL_WORKING) ? true : false;
113
114 if(accum.polling_goal_achieved())
115 break;
116 }
117 }
118
119 }
Botan::Entropy_Accumulator::get_io_buffer
MemoryRegion< byte > & get_io_buffer(size_t size)
Definition: entropy_src.h:38
Botan::clear_mem
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:32
Botan::Entropy_Accumulator::add
void add(const void *bytes, size_t length, double entropy_bits_per_byte)
Definition: entropy_src.h:70
Botan::DataSource_Command::read
size_t read(byte[], size_t)
Definition: unix_cmd.cpp:63
Botan::Unix_Program
Definition: unix_cmd.h:21
Botan::Unix_EntropySource::Unix_EntropySource
Unix_EntropySource(const std::vector< std::string > &path)
Definition: es_unix.cpp:38
Botan::DataSource_Command
Definition: unix_cmd.h:49
Botan::MemoryRegion< byte >
Botan
Definition: algo_base.h:14
Botan::Entropy_Accumulator::polling_goal_achieved
bool polling_goal_achieved() const
Definition: entropy_src.h:50
Botan::MemoryRegion::size
size_t size() const
Definition: secmem.h:29
Botan::Unix_EntropySource::poll
void poll(Entropy_Accumulator &accum)
Definition: es_unix.cpp:60
Botan::Entropy_Accumulator
Definition: entropy_src.h:19
Botan::DataSource_Command::end_of_data
bool end_of_data() const
Definition: unix_cmd.cpp:110
Botan::Unix_EntropySource::add_sources
void add_sources(const Unix_Program[], size_t)
Definition: es_unix.cpp:48