chgrp: Port to LibMain :^)

Author: https://github.com/kennethmyhra
Commit: https://github.com/SerenityOS/serenity/commit/c8080fc2ca9
Pull-request: https://github.com/SerenityOS/serenity/pull/11101
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/bgianfo ✅
Reviewed-by: https://github.com/creator1creeper1 ✅
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Userland/Utilities/CMakeLists.txt

@@ -64,6 +64,7 @@ target_link_libraries(cal LibMain)
 target_link_libraries(cat LibMain)
 target_link_libraries(checksum LibCrypto LibMain)
 target_link_libraries(chmod LibMain)
+target_link_libraries(chgrp LibMain)
 target_link_libraries(chres LibGUI)
 target_link_libraries(cksum LibCrypto)
 target_link_libraries(config LibConfig)

Userland/Utilities/chgrp.cpp

@@ -6,17 +6,14 @@
 
 #include <AK/String.h>
 #include <LibCore/ArgsParser.h>
+#include <LibCore/System.h>
+#include <LibMain/Main.h>
 #include <grp.h>
-#include <stdio.h>
 #include <string.h>
-#include <unistd.h>
 
-int main(int argc, char** argv)
+ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
-    if (pledge("stdio rpath chown", nullptr) < 0) {
-        perror("pledge");
-        return 1;
-    }
+    TRY(Core::System::pledge("stdio rpath chown", nullptr));
 
     const char* gid_arg = nullptr;
     const char* path = nullptr;
@@ -25,7 +22,7 @@ int main(int argc, char** argv)
     args_parser.set_general_help("Change the owning group for a file or directory.");
     args_parser.add_positional_argument(gid_arg, "Group ID", "gid");
     args_parser.add_positional_argument(path, "Path to file", "path");
-    args_parser.parse(argc, argv);
+    args_parser.parse(arguments);
 
     gid_t new_gid = -1;
 
@@ -46,11 +43,7 @@ int main(int argc, char** argv)
         new_gid = group->gr_gid;
     }
 
-    int rc = chown(path, -1, new_gid);
-    if (rc < 0) {
-        perror("chgrp");
-        return 1;
-    }
+    TRY(Core::System::chown(path, -1, new_gid));
 
     return 0;
 }