feat: add pxattr utility for cross-platform xattr manipulation

CMakeLists.txt

@@ -35,6 +35,7 @@ option(ENABLE_PERFMON "enable performance monitor in all tools" ON)
 option(ENABLE_FLAC "build with FLAC support" ON)
 option(ENABLE_RICEPP "build with RICEPP compression support" ON)
 option(WITH_UNIVERSAL_BINARY "build with universal binary" ON)
+option(WITH_PXATTR "build with pxattr binary" OFF)
 if(APPLE)
   option(USE_HOMEBREW_LIBARCHIVE "use libarchive from homebrew" ON)
 endif()
@@ -643,6 +644,11 @@ if(WITH_UNIVERSAL_BINARY)
           OUTPUT_NAME dwarfs-universal)
 endif()
 
+if(WITH_PXATTR)
+  add_executable(pxattr src/pxattr.cpp)
+  list(APPEND BINARY_TARGETS pxattr)
+endif()
+
 install(TARGETS mkdwarfs dwarfsck dwarfsbench dwarfsextract RUNTIME DESTINATION bin)
 
 list(APPEND MAIN_TARGETS mkdwarfs_main dwarfsck_main dwarfsbench_main

src/pxattr.cpp

@@ -0,0 +1,131 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/**
+ * \author     Marcus Holland-Moritz (github@mhxnet.de)
+ * \copyright  Copyright (c) Marcus Holland-Moritz
+ *
+ * This file is part of dwarfs.
+ *
+ * dwarfs is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * dwarfs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with dwarfs.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <iostream>
+
+#include <boost/program_options.hpp>
+
+#include "dwarfs/program_options_helpers.h"
+#include "dwarfs/types.h"
+#include "dwarfs/xattr.h"
+
+namespace dwarfs {
+
+namespace po = boost::program_options;
+namespace fs = std::filesystem;
+
+int pxattr_main(int argc, sys_char** argv) {
+  std::string name, value;
+  sys_string pathstr;
+
+  // clang-format off
+  po::options_description desc("Command line options");
+  desc.add_options()
+    ("get,g", po::value<std::string>(&name), "get extended attribute value")
+    ("set,s", po::value<std::string>(&name), "set extended attribute value")
+    ("remove,r", po::value<std::string>(&name), "remove extended attribute")
+    ("list,l", "list extended attributes")
+    ("path", po_sys_value<sys_string>(&pathstr), "path to the file or directory")
+    ("value,V", po::value<std::string>(&value), "new attribute value (with -s)")
+    ("help,h", "show this help message")
+    ;
+  // clang-format on
+
+  po::positional_options_description pos;
+  pos.add("path", 1);
+
+  po::variables_map vm;
+  po::store(po::basic_command_line_parser<sys_char>(argc, argv)
+                .options(desc)
+                .positional(pos)
+                .run(),
+            vm);
+  po::notify(vm);
+
+  if (vm.count("help")) {
+    std::cout << desc << std::endl;
+    return 0;
+  }
+
+  if (!vm.count("path")) {
+    std::cerr << "no path specified" << std::endl;
+    return 1;
+  }
+
+  if (vm.count("get") + vm.count("set") + vm.count("remove") +
+          vm.count("list") !=
+      1) {
+    std::cerr << "exactly one of --get, --set, --remove or --list must be "
+                 "specified\n";
+    return 1;
+  }
+
+  if (vm.count("set") != vm.count("value")) {
+    std::cerr << "missing value for --set\n";
+    return 1;
+  }
+
+  fs::path path(pathstr);
+
+  if (vm.count("get")) {
+    std::error_code ec;
+    std::string val = getxattr(path, name, ec);
+    if (ec) {
+      std::cerr << "getxattr failed: " << ec.message() << "\n";
+      return 1;
+    }
+    std::cout << val << "\n";
+  } else if (vm.count("set")) {
+    std::error_code ec;
+    setxattr(path, name, value, ec);
+    if (ec) {
+      std::cerr << "setxattr failed: " << ec.message() << "\n";
+      return 1;
+    }
+  } else if (vm.count("remove")) {
+    std::error_code ec;
+    removexattr(path, name, ec);
+    if (ec) {
+      std::cerr << "removexattr failed: " << ec.message() << "\n";
+      return 1;
+    }
+  } else if (vm.count("list")) {
+    std::error_code ec;
+    std::vector<std::string> attrs = listxattr(path, ec);
+    if (ec) {
+      std::cerr << "listxattr failed: " << ec.message() << "\n";
+      return 1;
+    }
+    for (const auto& attr : attrs) {
+      std::cout << attr << "\n";
+    }
+  }
+
+  std::cout << "successfully completed\n";
+
+  return 0;
+}
+
+} // namespace dwarfs
+
+int SYS_MAIN(int argc, dwarfs::sys_char** argv) {
+  return dwarfs::pxattr_main(argc, argv);
+}