Userland: Port tac to LibMain

Userland/Utilities/CMakeLists.txt

@@ -140,6 +140,7 @@ target_link_libraries(shot LibGUI)
 target_link_libraries(sql LibLine LibSQL LibIPC)
 target_link_libraries(stat LibMain)
 target_link_libraries(strace LibMain)
+target_link_libraries(tac LibMain)
 target_link_libraries(su LibCrypt LibMain)
 target_link_libraries(tar LibArchive LibCompress)
 target_link_libraries(telws LibProtocol LibLine)

Userland/Utilities/tac.cpp

@@ -1,27 +1,26 @@
 /*
- * Copyright (c) 2021, Federico Guerinoni <[email protected]>
+ * Copyright (c) 2021-2022, Federico Guerinoni <[email protected]>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <LibCore/ArgsParser.h>
+#include <LibCore/System.h>
+#include <LibMain/Main.h>
 #include <errno.h>
 #include <string.h>
 #include <unistd.h>
 
-int main(int argc, char** argv)
+ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
- if (pledge("stdio rpath", nullptr) < 0) {
- perror("pledge");
- return 1;
- }
+ TRY(Core::System::pledge("stdio rpath"));
 
  Vector<StringView> paths;
 
  Core::ArgsParser args_parser;
  args_parser.set_general_help("Concatenate files or pipes to stdout, last line first.");
  args_parser.add_positional_argument(paths, "File path(s)", "path", Core::ArgsParser::Required::No);
- args_parser.parse(argc, argv);
+ args_parser.parse(arguments);
 
  Vector<FILE*> streams;
  auto num_paths = paths.size();
@@ -54,10 +53,7 @@ int main(int argc, char** argv)
  }
  };
 
- if (pledge("stdio", nullptr) < 0) {
- perror("pledge");
- return 1;
- }
+ TRY(Core::System::pledge("stdio"));
 
  for (auto* stream : streams) {
  Vector<String> lines;