ArgumentParser: Add support for version information

apps/base64.cpp

@@ -10,6 +10,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Encode or decode Base64 data. If not given a file, reads from standard input.");
+    parser.add_system_program_info("base64"_sv);
     parser.add_positional_argument(path, "file", "-"_sv);
     parser.add_switch_argument(decode, 'd', "decode", "decode data");
     parser.add_switch_argument(allow_garbage, 'i', "ignore-garbage", "when decoding, ignore non-base64 characters");

apps/cat.cpp

@@ -27,6 +27,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Concatenate files to standard output."_sv);
+    parser.add_system_program_info("cat"_sv);
     parser.add_positional_argument(filename, "file"_sv, "-"_sv);
     Vector<StringView> extra_files = TRY(parser.parse(argc, argv));
 

apps/chmod.cpp

@@ -10,6 +10,7 @@ int main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Change the permissions of a file."_sv);
+    parser.add_system_program_info("chmod"_sv);
     parser.add_positional_argument(mode_string, "mode"_sv, true);
     parser.add_positional_argument(path, "path"_sv, true);
     parser.parse(argc, argv);

apps/chown.cpp

@@ -12,6 +12,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Change the owner and group of a file."_sv);
+    parser.add_system_program_info("chown"_sv);
     parser.add_positional_argument(user_and_group, "owner"_sv, true);
     parser.add_positional_argument(path, "path"_sv, true);
     parser.parse(argc, argv);

apps/date.cpp

@@ -11,6 +11,7 @@ int main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Display the current (or another) date and time."_sv);
+    parser.add_system_program_info("date"_sv);
     parser.add_value_argument(date, 'd', "date"_sv, true,
                               "the UNIX timestamp to display instead of the current time"_sv);
     parser.parse(argc, argv);

apps/edit.cpp

@@ -10,6 +10,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Edit a file using basic line-based shell editing."_sv);
+    parser.add_system_program_info("edit"_sv);
     parser.add_positional_argument(pathname, "path"_sv, true);
     parser.parse(argc, argv);
 

apps/ls.cpp

@@ -13,6 +13,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("List files contained in a directory (defaults to '.', the current directory)"_sv);
+    parser.add_system_program_info("ls"_sv);
     parser.add_positional_argument(pathname, "directory"_sv, "."_sv);
     parser.add_switch_argument(show_all, 'a', "all"_sv, "also list hidden files (whose filename begins with a dot)"_sv);
     parser.add_switch_argument(show_almost_all, 'A', "almost-all"_sv, "list all files except '.' and '..'"_sv);

apps/mkdir.cpp

@@ -31,6 +31,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Create directories."_sv);
+    parser.add_system_program_info("mkdir"_sv);
     parser.add_positional_argument(path, "path"_sv, true);
     parser.add_positional_argument(mode_string, "mode"_sv, "755"_sv);
     parser.add_switch_argument(recursive, 'p', "parents"_sv,

apps/rm.cpp

@@ -8,6 +8,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Remove a path from the file system."_sv);
+    parser.add_system_program_info("rm"_sv);
     parser.add_positional_argument(path, "path"_sv, true);
     parser.add_switch_argument(recursive, 'r', "recursive"_sv,
                                "remove a directory recursively (by default, rm removes only empty directories)"_sv);

apps/sh.cpp

@@ -46,6 +46,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("The Luna system's command shell."_sv);
+    parser.add_system_program_info("sh"_sv);
     parser.add_positional_argument(path, "path"_sv, "-"_sv);
     parser.add_value_argument(command, 'c', "command"_sv, true, "execute a single command and then exit"_sv);
     parser.parse(argc, argv);

apps/stat.cpp

@@ -19,6 +19,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Display file status.");
+    parser.add_system_program_info("stat"_sv);
     parser.add_positional_argument(path, "path", true);
     parser.parse(argc, argv);
 

apps/su.cpp

@@ -63,6 +63,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Switch to a different user (by default, root)."_sv);
+    parser.add_system_program_info("su"_sv);
     parser.add_positional_argument(name, "name"_sv, "root"_sv);
     parser.parse(argc, argv);
 

apps/uname.cpp

@@ -24,6 +24,7 @@ Result<int> luna_main(int argc, char** argv)
 
     os::ArgumentParser parser;
     parser.add_description("Print system information. If given no options, defaults to -s."_sv);
+    parser.add_system_program_info("uname"_sv);
     parser.add_switch_argument(all, 'a', "all"_sv, "print all information"_sv);
     parser.add_switch_argument(kernel_name, 's', "kernel-name"_sv, "print the kernel name"_sv);
     parser.add_switch_argument(node_name, 'n', "nodename"_sv, "print the network hostname"_sv);

libos/include/os/ArgumentParser.h

@@ -7,7 +7,7 @@ namespace os
     class ArgumentParser
     {
       public:
-        ArgumentParser(bool add_help = true);
+        ArgumentParser();
 
         void add_description(StringView description);
 
@@ -23,6 +23,22 @@ namespace os
 
         Result<Vector<StringView>> parse(int argc, char* const* argv);
 
+        struct ProgramInfo
+        {
+            StringView name;
+            StringView version;
+            StringView copyright;
+            StringView license;
+            StringView authors;
+            StringView package;
+        };
+
+        void add_program_info(ProgramInfo info);
+
+        /* Used from programs that are part of the Luna source tree, to add the same version info for all programs.
+         * Should not be used otherwise. */
+        void add_system_program_info(StringView name);
+
       private:
         struct PositionalArgument
         {
@@ -53,11 +69,16 @@ namespace os
         Result<void> usage(StringView program_name);
         void short_usage(StringView program_name);
 
+        void version();
+
         Vector<PositionalArgument> m_positional_args;
         Vector<SwitchArgument> m_switch_args;
         Vector<ValueArgument> m_value_args;
+        ProgramInfo m_program_info;
         StringView m_description = {};
         bool m_add_short_help_flag { false };
         bool m_add_long_help_flag { false };
+        bool m_add_short_version_flag { false };
+        bool m_add_long_version_flag { false };
     };
 }

libos/src/ArgumentParser.cpp

@@ -2,10 +2,11 @@
 #include <os/ArgumentParser.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/utsname.h>
 
 namespace os
 {
-    ArgumentParser::ArgumentParser(bool add_help) : m_add_short_help_flag(add_help), m_add_long_help_flag(add_help)
+    ArgumentParser::ArgumentParser() : m_add_short_help_flag(true), m_add_long_help_flag(true)
     {
     }
 
@@ -34,6 +35,8 @@ namespace os
 
         if (short_flag == 'h') m_add_short_help_flag = false;
         if (long_flag == "help"_sv) m_add_long_help_flag = false;
+        if (short_flag == 'v') m_add_short_version_flag = false;
+        if (long_flag == "version"_sv) m_add_long_version_flag = false;
 
         return m_switch_args.try_append(move(arg));
     }
@@ -45,6 +48,8 @@ namespace os
 
         if (short_flag == 'h') m_add_short_help_flag = false;
         if (long_flag == "help"_sv) m_add_long_help_flag = false;
+        if (short_flag == 'v') m_add_short_version_flag = false;
+        if (long_flag == "version"_sv) m_add_long_version_flag = false;
 
         return m_value_args.try_append(move(arg));
     }
@@ -56,10 +61,38 @@ namespace os
 
         if (short_flag == 'h') m_add_short_help_flag = false;
         if (long_flag == "help"_sv) m_add_long_help_flag = false;
+        if (short_flag == 'v') m_add_short_version_flag = false;
+        if (long_flag == "version"_sv) m_add_long_version_flag = false;
 
         return m_value_args.try_append(move(arg));
     }
 
+    constexpr auto copyright_text = "Copyright (C) 2023, the Luna authors.";
+    constexpr auto license_text = "Licensed under the BSD-2 license <https://opensource.org/license/bsd-2-clause/>";
+
+    void ArgumentParser::add_program_info(ProgramInfo info)
+    {
+        m_program_info = info;
+        m_add_short_version_flag = m_add_long_version_flag = true;
+    }
+
+    void ArgumentParser::add_system_program_info(StringView name)
+    {
+        static utsname info;
+        check(uname(&info) == 0);
+
+        ProgramInfo system_info {
+            .name = name,
+            .version = info.release,
+            .copyright = copyright_text,
+            .license = license_text,
+            .authors = {},
+            .package = "Luna system",
+        };
+
+        add_program_info(system_info);
+    }
+
     static bool looks_like_short_flag(StringView arg)
     {
         return arg.length() > 1 && arg[0] == '-';
@@ -107,6 +140,7 @@ namespace os
                     bool found = false;
 
                     if (m_add_long_help_flag && flag == "help"_sv) { TRY(usage(program_name)); }
+                    if (m_add_long_version_flag && flag == "version"_sv) { version(); }
 
                     for (const auto& current : m_switch_args)
                     {
@@ -144,6 +178,7 @@ namespace os
                         bool found = false;
 
                         if (m_add_short_help_flag && c == 'h') { TRY(usage(program_name)); }
+                        if (m_add_short_version_flag && c == 'v') { version(); }
 
                         // Last flag, this could be a value flag
                         if (j + 1 == flags.length())
@@ -284,6 +319,35 @@ namespace os
             }
         }
 
+        if (m_add_short_help_flag && m_add_long_help_flag)
+            printf("  -h, --%-20s %s\n", "help", "show this help message and exit");
+        else if (m_add_long_help_flag)
+            printf("      --%-20s %s\n", "help", "show this help message and exit");
+        else
+            printf("  -%-25c %s\n", 'h', "show this help message and exit");
+
+        if (m_add_short_version_flag && m_add_long_version_flag)
+            printf("  -v, --%-20s %s\n", "version", "show version information and exit");
+        else if (m_add_long_version_flag)
+            printf("      --%-20s %s\n", "version", "show version information and exit");
+        else
+            printf("  -%-25c %s\n", 'v', "show version information and exit");
+
+        exit(0);
+    }
+
+    void ArgumentParser::version()
+    {
+        if (m_program_info.package.is_empty())
+            printf("%s %s\n", m_program_info.name.chars(), m_program_info.version.chars());
+        else
+            printf("%s (%s) %s\n", m_program_info.name.chars(), m_program_info.package.chars(),
+                   m_program_info.version.chars());
+
+        printf("%s\n%s\n", m_program_info.copyright.chars(), m_program_info.license.chars());
+
+        if (!m_program_info.authors.is_empty()) printf("\n%s\n", m_program_info.authors.chars());
+
         exit(0);
     }