Userland: Add tar command

Author: https://github.com/petelliott
Commit: https://github.com/SerenityOS/serenity/commit/b7c7c80ee20
Pull-request: https://github.com/SerenityOS/serenity/pull/3660
Reviewed-by: https://github.com/asynts

Userland/CMakeLists.txt

@@ -35,6 +35,7 @@ target_link_libraries(passwd LibCrypt)
 target_link_libraries(paste LibGUI)
 target_link_libraries(pro LibProtocol)
 target_link_libraries(su LibCrypt)
+target_link_libraries(tar LibTar)
 target_link_libraries(test-crypto LibCrypto LibTLS LibLine)
 target_link_libraries(test-compress LibCompress)
 target_link_libraries(test-js LibJS LibLine LibCore)

Userland/tar.cpp

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2020, Peter Elliott <pelliott@ualberta.ca>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/LogStream.h>
+#include <AK/Vector.h>
+#include <LibCore/ArgsParser.h>
+#include <LibCore/FileStream.h>
+#include <LibTar/TarStream.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+
+constexpr size_t buffer_size = 4096;
+
+int main(int argc, char** argv)
+{
+    bool create = false;
+    bool extract = false;
+    bool list = false;
+    bool verbose = false;
+    const char* archive_file = nullptr;
+    Vector<const char*> paths;
+
+    Core::ArgsParser args_parser;
+    args_parser.add_option(create, "Create archive", "create", 'c');
+    args_parser.add_option(extract, "Extract archive", "extract", 'x');
+    args_parser.add_option(list, "List contents", "list", 't');
+    args_parser.add_option(verbose, "Print paths", "verbose", 'v');
+    args_parser.add_option(archive_file, "Archive file", "file", 'f', "FILE");
+    args_parser.add_positional_argument(paths, "Paths", "PATHS", Core::ArgsParser::Required::No);
+    args_parser.parse(argc, argv);
+
+    if (create + extract + list != 1) {
+        warnf("exactly one of -c, -x, and -t can be used");
+        return 1;
+    }
+
+    if (list || extract) {
+        auto file = Core::File::stdin();
+
+        if (archive_file) {
+            auto maybe_file = Core::File::open(archive_file, Core::IODevice::OpenMode::ReadOnly);
+            if (maybe_file.is_error()) {
+                warnf("Core::File::open: {}", maybe_file.error());
+                return 1;
+            }
+            file = maybe_file.value();
+        }
+        Core::InputFileStream input_stream(file);
+        Tar::TarStream tar_stream(input_stream);
+        for (; !tar_stream.finished(); tar_stream.advance()) {
+            if (list || verbose)
+                out() << tar_stream.header().file_name();
+
+            if (extract) {
+                Tar::TarFileStream file_stream = tar_stream.file_contents();
+
+                const Tar::Header& header = tar_stream.header();
+                switch (header.type_flag()) {
+                case Tar::NormalFile:
+                case Tar::AlternateNormalFile: {
+                    int fd = open(String(header.file_name()).characters(), O_CREAT | O_WRONLY, header.mode());
+                    if (fd < 0) {
+                        perror("open");
+                        return 1;
+                    }
+
+                    Array<u8, buffer_size> buffer;
+                    size_t nread;
+                    while ((nread = file_stream.read(buffer)) > 0) {
+                        if (write(fd, buffer.data(), nread) < 0) {
+                            perror("write");
+                            return 1;
+                        }
+                    }
+                    close(fd);
+                    break;
+                }
+                case Tar::Directory: {
+                    if (mkdir(String(header.file_name()).characters(), header.mode())) {
+                        perror("mkdir");
+                        return 1;
+                    }
+                    break;
+                }
+                default:
+                    // FIXME: Implement other file types
+                    ASSERT_NOT_REACHED();
+                }
+            }
+        }
+        input_stream.close();
+        return 0;
+    }
+
+    // FIXME: Implement other operations.
+    ASSERT_NOT_REACHED();
+
+    return 0;
+}