Bitcoin Core  0.20.99
P2P Digital Currency
settings.cpp
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1 // Copyright (c) 2019 The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 
5 #include <util/settings.h>
6 
7 #include <tinyformat.h>
8 #include <univalue.h>
9 
10 namespace util {
11 namespace {
12 
13 enum class Source {
14  FORCED,
15  COMMAND_LINE,
16  RW_SETTINGS,
17  CONFIG_FILE_NETWORK_SECTION,
18  CONFIG_FILE_DEFAULT_SECTION
19 };
20 
26 template <typename Fn>
27 static void MergeSettings(const Settings& settings, const std::string& section, const std::string& name, Fn&& fn)
28 {
29  // Merge in the forced settings
30  if (auto* value = FindKey(settings.forced_settings, name)) {
31  fn(SettingsSpan(*value), Source::FORCED);
32  }
33  // Merge in the command-line options
34  if (auto* values = FindKey(settings.command_line_options, name)) {
35  fn(SettingsSpan(*values), Source::COMMAND_LINE);
36  }
37  // Merge in the read-write settings
38  if (const SettingsValue* value = FindKey(settings.rw_settings, name)) {
39  fn(SettingsSpan(*value), Source::RW_SETTINGS);
40  }
41  // Merge in the network-specific section of the config file
42  if (!section.empty()) {
43  if (auto* map = FindKey(settings.ro_config, section)) {
44  if (auto* values = FindKey(*map, name)) {
45  fn(SettingsSpan(*values), Source::CONFIG_FILE_NETWORK_SECTION);
46  }
47  }
48  }
49  // Merge in the default section of the config file
50  if (auto* map = FindKey(settings.ro_config, "")) {
51  if (auto* values = FindKey(*map, name)) {
52  fn(SettingsSpan(*values), Source::CONFIG_FILE_DEFAULT_SECTION);
53  }
54  }
55 }
56 } // namespace
57 
58 bool ReadSettings(const fs::path& path, std::map<std::string, SettingsValue>& values, std::vector<std::string>& errors)
59 {
60  values.clear();
61  errors.clear();
62 
63  fsbridge::ifstream file;
64  file.open(path);
65  if (!file.is_open()) return true; // Ok for file not to exist.
66 
67  SettingsValue in;
68  if (!in.read(std::string{std::istreambuf_iterator<char>(file), std::istreambuf_iterator<char>()})) {
69  errors.emplace_back(strprintf("Unable to parse settings file %s", path.string()));
70  return false;
71  }
72 
73  if (file.fail()) {
74  errors.emplace_back(strprintf("Failed reading settings file %s", path.string()));
75  return false;
76  }
77  file.close(); // Done with file descriptor. Release while copying data.
78 
79  if (!in.isObject()) {
80  errors.emplace_back(strprintf("Found non-object value %s in settings file %s", in.write(), path.string()));
81  return false;
82  }
83 
84  const std::vector<std::string>& in_keys = in.getKeys();
85  const std::vector<SettingsValue>& in_values = in.getValues();
86  for (size_t i = 0; i < in_keys.size(); ++i) {
87  auto inserted = values.emplace(in_keys[i], in_values[i]);
88  if (!inserted.second) {
89  errors.emplace_back(strprintf("Found duplicate key %s in settings file %s", in_keys[i], path.string()));
90  }
91  }
92  return errors.empty();
93 }
94 
95 bool WriteSettings(const fs::path& path,
96  const std::map<std::string, SettingsValue>& values,
97  std::vector<std::string>& errors)
98 {
100  for (const auto& value : values) {
101  out.__pushKV(value.first, value.second);
102  }
103  fsbridge::ofstream file;
104  file.open(path);
105  if (file.fail()) {
106  errors.emplace_back(strprintf("Error: Unable to open settings file %s for writing", path.string()));
107  return false;
108  }
109  file << out.write(/* prettyIndent= */ 1, /* indentLevel= */ 4) << std::endl;
110  file.close();
111  return true;
112 }
113 
115  const std::string& section,
116  const std::string& name,
117  bool ignore_default_section_config,
118  bool get_chain_name)
119 {
120  SettingsValue result;
121  bool done = false; // Done merging any more settings sources.
122  MergeSettings(settings, section, name, [&](SettingsSpan span, Source source) {
123  // Weird behavior preserved for backwards compatibility: Apply negated
124  // setting even if non-negated setting would be ignored. A negated
125  // value in the default section is applied to network specific options,
126  // even though normal non-negated values there would be ignored.
127  const bool never_ignore_negated_setting = span.last_negated();
128 
129  // Weird behavior preserved for backwards compatibility: Take first
130  // assigned value instead of last. In general, later settings take
131  // precedence over early settings, but for backwards compatibility in
132  // the config file the precedence is reversed for all settings except
133  // chain name settings.
134  const bool reverse_precedence =
135  (source == Source::CONFIG_FILE_NETWORK_SECTION || source == Source::CONFIG_FILE_DEFAULT_SECTION) &&
136  !get_chain_name;
137 
138  // Weird behavior preserved for backwards compatibility: Negated
139  // -regtest and -testnet arguments which you would expect to override
140  // values set in the configuration file are currently accepted but
141  // silently ignored. It would be better to apply these just like other
142  // negated values, or at least warn they are ignored.
143  const bool skip_negated_command_line = get_chain_name;
144 
145  if (done) return;
146 
147  // Ignore settings in default config section if requested.
148  if (ignore_default_section_config && source == Source::CONFIG_FILE_DEFAULT_SECTION &&
149  !never_ignore_negated_setting) {
150  return;
151  }
152 
153  // Skip negated command line settings.
154  if (skip_negated_command_line && span.last_negated()) return;
155 
156  if (!span.empty()) {
157  result = reverse_precedence ? span.begin()[0] : span.end()[-1];
158  done = true;
159  } else if (span.last_negated()) {
160  result = false;
161  done = true;
162  }
163  });
164  return result;
165 }
166 
167 std::vector<SettingsValue> GetSettingsList(const Settings& settings,
168  const std::string& section,
169  const std::string& name,
170  bool ignore_default_section_config)
171 {
172  std::vector<SettingsValue> result;
173  bool done = false; // Done merging any more settings sources.
174  bool prev_negated_empty = false;
175  MergeSettings(settings, section, name, [&](SettingsSpan span, Source source) {
176  // Weird behavior preserved for backwards compatibility: Apply config
177  // file settings even if negated on command line. Negating a setting on
178  // command line will ignore earlier settings on the command line and
179  // ignore settings in the config file, unless the negated command line
180  // value is followed by non-negated value, in which case config file
181  // settings will be brought back from the dead (but earlier command
182  // line settings will still be ignored).
183  const bool add_zombie_config_values =
184  (source == Source::CONFIG_FILE_NETWORK_SECTION || source == Source::CONFIG_FILE_DEFAULT_SECTION) &&
185  !prev_negated_empty;
186 
187  // Ignore settings in default config section if requested.
188  if (ignore_default_section_config && source == Source::CONFIG_FILE_DEFAULT_SECTION) return;
189 
190  // Add new settings to the result if isn't already complete, or if the
191  // values are zombies.
192  if (!done || add_zombie_config_values) {
193  for (const auto& value : span) {
194  if (value.isArray()) {
195  result.insert(result.end(), value.getValues().begin(), value.getValues().end());
196  } else {
197  result.push_back(value);
198  }
199  }
200  }
201 
202  // If a setting was negated, or if a setting was forced, set
203  // done to true to ignore any later lower priority settings.
204  done |= span.negated() > 0 || source == Source::FORCED;
205 
206  // Update the negated and empty state used for the zombie values check.
207  prev_negated_empty |= span.last_negated() && result.empty();
208  });
209  return result;
210 }
211 
212 bool OnlyHasDefaultSectionSetting(const Settings& settings, const std::string& section, const std::string& name)
213 {
214  bool has_default_section_setting = false;
215  bool has_other_setting = false;
216  MergeSettings(settings, section, name, [&](SettingsSpan span, Source source) {
217  if (span.empty()) return;
218  else if (source == Source::CONFIG_FILE_DEFAULT_SECTION) has_default_section_setting = true;
219  else has_other_setting = true;
220  });
221  // If a value is set in the default section and not explicitly overwritten by the
222  // user on the command line or in a different section, then we want to enable
223  // warnings about the value being ignored.
224  return has_default_section_setting && !has_other_setting;
225 }
226 
227 SettingsSpan::SettingsSpan(const std::vector<SettingsValue>& vec) noexcept : SettingsSpan(vec.data(), vec.size()) {}
228 const SettingsValue* SettingsSpan::begin() const { return data + negated(); }
229 const SettingsValue* SettingsSpan::end() const { return data + size; }
230 bool SettingsSpan::empty() const { return size == 0 || last_negated(); }
231 bool SettingsSpan::last_negated() const { return size > 0 && data[size - 1].isFalse(); }
232 size_t SettingsSpan::negated() const
233 {
234  for (size_t i = size; i > 0; --i) {
235  if (data[i - 1].isFalse()) return i; // Return number of negated values (position of last false value)
236  }
237  return 0;
238 }
239 
240 } // namespace util
std::map< std::string, SettingsValue > rw_settings
Map of setting name to read-write file setting value.
Definition: settings.h:37
Stored settings.
Definition: settings.h:31
bool isObject() const
Definition: univalue.h:84
bool OnlyHasDefaultSectionSetting(const Settings &settings, const std::string &section, const std::string &name)
Return true if a setting is set in the default config file section, and not overridden by a higher pr...
Definition: settings.cpp:212
Definition: httprpc.h:8
const std::vector< UniValue > & getValues() const
size_t negated() const
Number of negated values.
Definition: settings.cpp:232
bool read(const char *raw, size_t len)
#define strprintf
Format arguments and return the string or write to given std::ostream (see tinyformat::format doc for...
Definition: tinyformat.h:1164
SettingsValue GetSetting(const Settings &settings, const std::string &section, const std::string &name, bool ignore_default_section_config, bool get_chain_name)
Get settings value from combined sources: forced settings, command line arguments, runtime read-write settings, and the read-only config file.
Definition: settings.cpp:114
const SettingsValue * end() const
Pointer to end of values.
Definition: settings.cpp:229
fs::ifstream ifstream
Definition: fs.h:90
bool last_negated() const
True if the last value is negated.
Definition: settings.cpp:231
const std::vector< std::string > & getKeys() const
fs::ofstream ofstream
Definition: fs.h:91
auto FindKey(Map &&map, Key &&key) -> decltype(&map.at(key))
Map lookup helper.
Definition: settings.h:100
std::vector< SettingsValue > GetSettingsList(const Settings &settings, const std::string &section, const std::string &name, bool ignore_default_section_config)
Get combined setting value similar to GetSetting(), except if setting was specified multiple times...
Definition: settings.cpp:167
bool WriteSettings(const fs::path &path, const std::map< std::string, SettingsValue > &values, std::vector< std::string > &errors)
Write settings file.
Definition: settings.cpp:95
const char * source
Definition: rpcconsole.cpp:52
bool empty() const
True if there are any non-negated values.
Definition: settings.cpp:230
const char * name
Definition: rest.cpp:41
std::map< std::string, std::vector< SettingsValue > > command_line_options
Map of setting name to list of command line values.
Definition: settings.h:35
std::string write(unsigned int prettyIndent=0, unsigned int indentLevel=0) const
const SettingsValue * begin() const
Pointer to first non-negated value.
Definition: settings.cpp:228
Accessor for list of settings that skips negated values when iterated over.
Definition: settings.h:83
SettingsSpan()=default
std::map< std::string, std::map< std::string, std::vector< SettingsValue > > > ro_config
Map of config section name and setting name to list of config file values.
Definition: settings.h:39
std::map< std::string, SettingsValue > forced_settings
Map of setting name to forced setting value.
Definition: settings.h:33
void __pushKV(const std::string &key, const UniValue &val)
Definition: univalue.cpp:127
bool ReadSettings(const fs::path &path, std::map< std::string, SettingsValue > &values, std::vector< std::string > &errors)
Read settings file.
Definition: settings.cpp:58