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	 ed4c2f2f8e
			
		
	
	
		ed4c2f2f8e
		
	
	
	
	
		
			
			This generally seems like a better name, especially if we somehow also need a better name for "read the entire buffer, but not the entire file" somewhere down the line.
		
			
				
	
	
		
			120 lines
		
	
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			120 lines
		
	
	
	
		
			3.7 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * Copyright (c) 2022, Alex Major
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #include <LibCore/ArgsParser.h>
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| #include <LibCore/DirIterator.h>
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| #include <LibCore/Stream.h>
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| #include <LibMain/Main.h>
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| 
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| static bool s_set_variable = false;
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| 
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| static DeprecatedString get_variable(StringView name)
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| {
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|     auto path = DeprecatedString::formatted("/sys/kernel/variables/{}", name);
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|     auto file = Core::Stream::File::open(path, Core::Stream::OpenMode::Read);
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|     if (file.is_error()) {
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|         warnln("Failed to open {}: {}", path, file.error());
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|         return {};
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|     }
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|     auto buffer = file.value()->read_until_eof();
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|     if (buffer.is_error()) {
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|         warnln("Failed to read {}: {}", path, buffer.error());
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|         return {};
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|     }
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|     return { (char const*)buffer.value().data(), buffer.value().size(), Chomp };
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| }
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| 
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| static bool read_variable(StringView name)
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| {
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|     auto value = get_variable(name);
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|     if (value.is_null())
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|         return false;
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|     outln("{} = {}", name, value);
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|     return true;
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| }
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| 
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| static bool write_variable(StringView name, StringView value)
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| {
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|     auto old_value = get_variable(name);
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|     if (old_value.is_null())
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|         return false;
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|     auto path = DeprecatedString::formatted("/sys/kernel/variables/{}", name);
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|     auto file = Core::Stream::File::open(path, Core::Stream::OpenMode::Write);
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|     if (file.is_error()) {
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|         warnln("Failed to open {}: {}", path, file.error());
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|         return false;
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|     }
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|     if (auto result = file.value()->write(value.bytes()); result.is_error()) {
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|         warnln("Failed to write {}: {}", path, result.error());
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|         return false;
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|     }
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|     outln("{}: {} -> {}", name, old_value, value);
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|     return true;
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| }
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| 
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| static int handle_variables(Vector<StringView> const& variables)
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| {
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|     bool success = false;
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|     for (auto const& variable : variables) {
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|         auto maybe_index = variable.find('=');
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|         if (!maybe_index.has_value()) {
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|             success = read_variable(variable);
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|             continue;
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|         }
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|         auto equal_index = maybe_index.release_value();
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|         auto name = variable.substring_view(0, equal_index);
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|         auto value = variable.substring_view(equal_index + 1, variable.length() - equal_index - 1);
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|         if (name.is_empty())
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|             warnln("Malformed setting '{}'", variable);
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|         else if (!s_set_variable)
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|             warnln("Must specify '-w' to set variables");
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|         else
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|             success = write_variable(name, value);
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|     }
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|     return success ? 0 : 1;
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| }
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| 
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| static int handle_show_all()
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| {
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|     Core::DirIterator di("/sys/kernel/variables", Core::DirIterator::SkipDots);
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|     if (di.has_error()) {
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|         outln("DirIterator: {}", di.error_string());
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|         return 1;
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|     }
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| 
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|     bool success = false;
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|     while (di.has_next()) {
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|         auto name = di.next_path();
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|         success = read_variable(name);
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|     }
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|     return success ? 0 : 1;
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| }
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| 
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| ErrorOr<int> serenity_main(Main::Arguments arguments)
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| {
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|     bool show_all = false;
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|     Vector<StringView> variables;
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| 
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|     Core::ArgsParser args_parser;
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|     args_parser.set_general_help("Show or modify system-internal values. This requires root, and can crash your system.");
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|     args_parser.add_option(show_all, "Show all variables", "all", 'a');
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|     args_parser.add_option(s_set_variable, "Set variables", "write", 'w');
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|     args_parser.add_positional_argument(variables, "variable[=value]", "variables", Core::ArgsParser::Required::No);
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|     args_parser.parse(arguments);
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| 
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|     if (!show_all && variables.is_empty()) {
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|         args_parser.print_usage(stdout, arguments.argv[0]);
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|         return 1;
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|     }
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| 
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|     if (show_all) {
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|         // Ignore `variables`, even if they are supplied. Just like the real procps does.
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|         return handle_show_all();
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|     }
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| 
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|     return handle_variables(variables);
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| }
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