apps: Add cp

apps/CMakeLists.txt

@@ -32,3 +32,4 @@ luna_app(ln.cpp ln)
 luna_app(mktemp.cpp mktemp)
 luna_app(sysfuzz.cpp sysfuzz)
 luna_app(pivot_root.cpp pivot_root)
+luna_app(cp.cpp cp)

apps/cp.cpp

@@ -0,0 +1,50 @@
+#include <luna/PathParser.h>
+#include <os/ArgumentParser.h>
+#include <os/File.h>
+#include <os/FileSystem.h>
+
+using os::File;
+
+Result<int> luna_main(int argc, char** argv)
+{
+    StringView source;
+    StringView destination;
+    bool verbose { false };
+
+    os::ArgumentParser parser;
+    parser.add_description("Copy files or directories."_sv);
+    parser.add_system_program_info("cp"_sv);
+    parser.add_positional_argument(source, "source"_sv, true);
+    parser.add_positional_argument(destination, "destination"_sv, true);
+    parser.add_switch_argument(verbose, 'v', "verbose"_sv, "show more information"_sv);
+    parser.parse(argc, argv);
+
+    SharedPtr<File> source_file = TRY(os::File::open(source, File::ReadOnly));
+    SharedPtr<File> destination_file;
+
+    struct stat st;
+    TRY(os::FileSystem::stat(source_file->fd(), st, true));
+    umask(0);
+
+    if (os::FileSystem::is_directory(destination, true))
+    {
+        auto basename = TRY(PathParser::basename(source));
+        auto path = TRY(PathParser::join_paths(destination, basename.view()));
+
+        destination_file = TRY(File::open_or_create(path.view(), File::ReadWrite, st.st_mode & ~S_IFMT));
+    }
+    else
+        destination_file = TRY(File::open_or_create(destination, File::ReadWrite, st.st_mode & ~S_IFMT));
+
+    if (verbose) os::eprintln("copying %s to %s", source.chars(), destination.chars());
+
+    auto buf = TRY(Buffer::create_sized(4096));
+    while (1)
+    {
+        TRY(source_file->read(buf, 4096));
+        if (buf.is_empty()) break;
+        destination_file->write(buf);
+    }
+
+    return 0;
+}