settings.cpp raw
1 // Copyright (c) 2019-present 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 <common/settings.h>
6
7 #include <bitcoin-build-config.h> // IWYU pragma: keep
8
9 #include <tinyformat.h>
10 #include <univalue.h>
11 #include <util/fs.h>
12
13 #include <algorithm>
14 #include <fstream>
15 #include <iterator>
16 #include <map>
17 #include <string>
18 #include <utility>
19 #include <vector>
20
21 namespace common {
22 namespace {
23
24 enum class Source {
25 FORCED,
26 COMMAND_LINE,
27 RW_SETTINGS,
28 CONFIG_FILE_NETWORK_SECTION,
29 CONFIG_FILE_DEFAULT_SECTION
30 };
31
32 // Json object key for the auto-generated warning comment
33 const std::string SETTINGS_WARN_MSG_KEY{"_warning_"};
34
35 //! Merge settings from multiple sources in precedence order:
36 //! Forced config > command line > read-write settings file > config file network-specific section > config file default section
37 //!
38 //! This function is provided with a callback function fn that contains
39 //! specific logic for how to merge the sources.
40 template <typename Fn>
41 static void MergeSettings(const Settings& settings, const std::string& section, const std::string& name, Fn&& fn)
42 {
43 // Merge in the forced settings
44 if (auto* value = FindKey(settings.forced_settings, name)) {
45 fn(SettingsSpan(*value), Source::FORCED);
46 }
47 // Merge in the command-line options
48 if (auto* values = FindKey(settings.command_line_options, name)) {
49 fn(SettingsSpan(*values), Source::COMMAND_LINE);
50 }
51 // Merge in the read-write settings
52 if (const SettingsValue* value = FindKey(settings.rw_settings, name)) {
53 fn(SettingsSpan(*value), Source::RW_SETTINGS);
54 }
55 // Merge in the network-specific section of the config file
56 if (!section.empty()) {
57 if (auto* map = FindKey(settings.ro_config, section)) {
58 if (auto* values = FindKey(*map, name)) {
59 fn(SettingsSpan(*values), Source::CONFIG_FILE_NETWORK_SECTION);
60 }
61 }
62 }
63 // Merge in the default section of the config file
64 if (auto* map = FindKey(settings.ro_config, "")) {
65 if (auto* values = FindKey(*map, name)) {
66 fn(SettingsSpan(*values), Source::CONFIG_FILE_DEFAULT_SECTION);
67 }
68 }
69 }
70 } // namespace
71
72 bool ReadSettings(const fs::path& path, std::map<std::string, SettingsValue>& values, std::vector<std::string>& errors)
73 {
74 values.clear();
75 errors.clear();
76
77 // Ok for file to not exist
78 if (!fs::exists(path)) return true;
79
80 std::ifstream file;
81 file.open(path.std_path());
82 if (!file.is_open()) {
83 errors.emplace_back(strprintf("%s. Please check permissions.", fs::PathToString(path)));
84 return false;
85 }
86
87 SettingsValue in;
88 if (!in.read(std::string{std::istreambuf_iterator<char>(file), std::istreambuf_iterator<char>()})) {
89 errors.emplace_back(strprintf("Settings file %s does not contain valid JSON. This may be caused by a crash, power loss, full disk, or storage error, "
90 "and can be fixed by removing the file, which will reset settings to default values.",
91 fs::PathToString(path)));
92 return false;
93 }
94
95 if (file.fail()) {
96 errors.emplace_back(strprintf("Failed reading settings file %s", fs::PathToString(path)));
97 return false;
98 }
99 file.close(); // Done with file descriptor. Release while copying data.
100
101 if (!in.isObject()) {
102 errors.emplace_back(strprintf("Found non-object value %s in settings file %s", in.write(), fs::PathToString(path)));
103 return false;
104 }
105
106 const std::vector<std::string>& in_keys = in.getKeys();
107 const std::vector<SettingsValue>& in_values = in.getValues();
108 for (size_t i = 0; i < in_keys.size(); ++i) {
109 auto inserted = values.emplace(in_keys[i], in_values[i]);
110 if (!inserted.second) {
111 errors.emplace_back(strprintf("Found duplicate key %s in settings file %s", in_keys[i], fs::PathToString(path)));
112 values.clear();
113 break;
114 }
115 }
116
117 // Remove auto-generated warning comment from the accessible settings.
118 values.erase(SETTINGS_WARN_MSG_KEY);
119
120 return errors.empty();
121 }
122
123 bool WriteSettings(const fs::path& path,
124 const std::map<std::string, SettingsValue>& values,
125 std::vector<std::string>& errors)
126 {
127 SettingsValue out(SettingsValue::VOBJ);
128 // Add auto-generated warning comment
129 out.pushKV(SETTINGS_WARN_MSG_KEY, strprintf("This file is automatically generated and updated by %s. Please do not edit this file while the node "
130 "is running, as any changes might be ignored or overwritten.", CLIENT_NAME));
131 // Push settings values
132 for (const auto& value : values) {
133 out.pushKVEnd(value.first, value.second);
134 }
135 std::ofstream file;
136 file.open(path.std_path());
137 if (file.fail()) {
138 errors.emplace_back(strprintf("Error: Unable to open settings file %s for writing", fs::PathToString(path)));
139 return false;
140 }
141 file << out.write(/* prettyIndent= */ 4, /* indentLevel= */ 1) << std::endl;
142 if (file.fail()) {
143 errors.emplace_back(strprintf("Error: Unable to write settings file %s", fs::PathToString(path)));
144 return false;
145 }
146 file.close();
147 if (file.fail()) {
148 errors.emplace_back(strprintf("Error: Unable to close settings file %s", fs::PathToString(path)));
149 return false;
150 }
151 return true;
152 }
153
154 SettingsValue GetSetting(const Settings& settings,
155 const std::string& section,
156 const std::string& name,
157 bool ignore_default_section_config,
158 bool ignore_nonpersistent,
159 bool get_chain_type)
160 {
161 SettingsValue result;
162 bool done = false; // Done merging any more settings sources.
163 MergeSettings(settings, section, name, [&](SettingsSpan span, Source source) {
164 // Weird behavior preserved for backwards compatibility: Apply negated
165 // setting even if non-negated setting would be ignored. A negated
166 // value in the default section is applied to network specific options,
167 // even though normal non-negated values there would be ignored.
168 const bool never_ignore_negated_setting = span.last_negated();
169
170 // Weird behavior preserved for backwards compatibility: Take first
171 // assigned value instead of last. In general, later settings take
172 // precedence over early settings, but for backwards compatibility in
173 // the config file the precedence is reversed for all settings except
174 // chain type settings.
175 const bool reverse_precedence =
176 (source == Source::CONFIG_FILE_NETWORK_SECTION || source == Source::CONFIG_FILE_DEFAULT_SECTION) &&
177 !get_chain_type;
178
179 // Weird behavior preserved for backwards compatibility: Negated
180 // -regtest and -testnet arguments which you would expect to override
181 // values set in the configuration file are currently accepted but
182 // silently ignored. It would be better to apply these just like other
183 // negated values, or at least warn they are ignored.
184 const bool skip_negated_command_line = get_chain_type;
185
186 if (done) return;
187
188 // Ignore settings in default config section if requested.
189 if (ignore_default_section_config && source == Source::CONFIG_FILE_DEFAULT_SECTION &&
190 !never_ignore_negated_setting) {
191 return;
192 }
193
194 // Ignore nonpersistent settings if requested.
195 if (ignore_nonpersistent && (source == Source::COMMAND_LINE || source == Source::FORCED)) return;
196
197 // Skip negated command line settings.
198 if (skip_negated_command_line && span.last_negated()) return;
199
200 if (!span.empty()) {
201 result = reverse_precedence ? span.begin()[0] : span.end()[-1];
202 done = true;
203 } else if (span.last_negated()) {
204 result = false;
205 done = true;
206 }
207 });
208 return result;
209 }
210
211 std::vector<SettingsValue> GetSettingsList(const Settings& settings,
212 const std::string& section,
213 const std::string& name,
214 bool ignore_default_section_config)
215 {
216 std::vector<SettingsValue> result;
217 bool done = false; // Done merging any more settings sources.
218 bool prev_negated_empty = false;
219 MergeSettings(settings, section, name, [&](SettingsSpan span, Source source) {
220 // Weird behavior preserved for backwards compatibility: Apply config
221 // file settings even if negated on command line. Negating a setting on
222 // command line will ignore earlier settings on the command line and
223 // ignore settings in the config file, unless the negated command line
224 // value is followed by non-negated value, in which case config file
225 // settings will be brought back from the dead (but earlier command
226 // line settings will still be ignored).
227 const bool add_zombie_config_values =
228 (source == Source::CONFIG_FILE_NETWORK_SECTION || source == Source::CONFIG_FILE_DEFAULT_SECTION) &&
229 !prev_negated_empty;
230
231 // Ignore settings in default config section if requested.
232 if (ignore_default_section_config && source == Source::CONFIG_FILE_DEFAULT_SECTION) return;
233
234 // Add new settings to the result if isn't already complete, or if the
235 // values are zombies.
236 if (!done || add_zombie_config_values) {
237 for (const auto& value : span) {
238 if (value.isArray()) {
239 result.insert(result.end(), value.getValues().begin(), value.getValues().end());
240 } else {
241 result.push_back(value);
242 }
243 }
244 }
245
246 // If a setting was negated, or if a setting was forced, set
247 // done to true to ignore any later lower priority settings.
248 done |= span.negated() > 0 || source == Source::FORCED;
249
250 // Update the negated and empty state used for the zombie values check.
251 prev_negated_empty |= span.last_negated() && result.empty();
252 });
253 return result;
254 }
255
256 bool OnlyHasDefaultSectionSetting(const Settings& settings, const std::string& section, const std::string& name)
257 {
258 bool has_default_section_setting = false;
259 bool has_other_setting = false;
260 MergeSettings(settings, section, name, [&](SettingsSpan span, Source source) {
261 if (span.empty()) return;
262 else if (source == Source::CONFIG_FILE_DEFAULT_SECTION) has_default_section_setting = true;
263 else has_other_setting = true;
264 });
265 // If a value is set in the default section and not explicitly overwritten by the
266 // user on the command line or in a different section, then we want to enable
267 // warnings about the value being ignored.
268 return has_default_section_setting && !has_other_setting;
269 }
270
271 SettingsSpan::SettingsSpan(const std::vector<SettingsValue>& vec) noexcept : SettingsSpan(vec.data(), vec.size()) {}
272 const SettingsValue* SettingsSpan::begin() const { return data + negated(); }
273 const SettingsValue* SettingsSpan::end() const { return data + size; }
274 bool SettingsSpan::empty() const { return size == 0 || last_negated(); }
275 bool SettingsSpan::last_negated() const { return size > 0 && data[size - 1].isFalse(); }
276 size_t SettingsSpan::negated() const
277 {
278 for (size_t i = size; i > 0; --i) {
279 if (data[i - 1].isFalse()) return i; // Return number of negated values (position of last false value)
280 }
281 return 0;
282 }
283
284 } // namespace common
285