4 files changed, 481 insertions, 0 deletions
diff --git a/Userland/Libraries/CMakeLists.txt b/Userland/Libraries/CMakeLists.txt
index bb5403fbd6..83c0cec63e 100644
--- a/Userland/Libraries/CMakeLists.txt
+++ b/Userland/Libraries/CMakeLists.txt
@@ -20,6 +20,7 @@ add_subdirectory(LibDNS)
 add_subdirectory(LibDSP)
 add_subdirectory(LibEDID)
 add_subdirectory(LibELF)
+add_subdirectory(LibFileSystem)
 add_subdirectory(LibFileSystemAccessClient)
 add_subdirectory(LibGemini)
 add_subdirectory(LibGfx)
diff --git a/Userland/Libraries/LibFileSystem/CMakeLists.txt b/Userland/Libraries/LibFileSystem/CMakeLists.txt
new file mode 100644
index 0000000000..1e4e1871ff
--- /dev/null
+++ b/Userland/Libraries/LibFileSystem/CMakeLists.txt
@@ -0,0 +1,6 @@
+set(SOURCES
+    FileSystem.cpp
+)
+
+serenity_lib(LibFileSystem filesystem)
+target_link_libraries(LibFileSystem PRIVATE LibCore)
diff --git a/Userland/Libraries/LibFileSystem/FileSystem.cpp b/Userland/Libraries/LibFileSystem/FileSystem.cpp
new file mode 100644
index 0000000000..2e181fa937
--- /dev/null
+++ b/Userland/Libraries/LibFileSystem/FileSystem.cpp
@@ -0,0 +1,395 @@
+/*
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2023, Cameron Youell <cameronyouell@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/LexicalPath.h>
+#include <LibCore/DirIterator.h>
+#include <LibCore/System.h>
+#include <LibFileSystem/FileSystem.h>
+
+#ifdef AK_OS_SERENITY
+#    include <serenity.h>
+#endif
+
+// On Linux distros that use glibc `basename` is defined as a macro that expands to `__xpg_basename`, so we undefine it
+#if defined(AK_OS_LINUX) && defined(basename)
+#    undef basename
+#endif
+
+namespace FileSystem {
+
+ErrorOr<String> current_working_directory()
+{
+    auto cwd = TRY(Core::System::getcwd());
+    return TRY(String::from_deprecated_string({ cwd }));
+}
+
+ErrorOr<String> absolute_path(StringView path)
+{
+    if (exists(path))
+        return TRY(real_path(path));
+
+    if (path.starts_with("/"sv))
+        return TRY(String::from_deprecated_string(LexicalPath::canonicalized_path(path)));
+
+    auto working_directory = TRY(current_working_directory());
+    auto full_path = LexicalPath::join(working_directory, path).string();
+
+    return TRY(String::from_deprecated_string(LexicalPath::canonicalized_path(full_path)));
+}
+
+ErrorOr<String> real_path(StringView path)
+{
+    if (path.is_null())
+        return Error::from_errno(ENOENT);
+
+    DeprecatedString dep_path = path;
+    auto* real_path = realpath(dep_path.characters(), nullptr);
+
+    if (!real_path)
+        return Error::from_syscall("realpath"sv, -errno);
+
+    return TRY(String::from_deprecated_string({ real_path }));
+}
+
+bool exists(StringView path)
+{
+    return !Core::System::stat(path).is_error();
+}
+
+bool exists(int fd)
+{
+    return !Core::System::fstat(fd).is_error();
+}
+
+bool is_device(StringView path)
+{
+    auto st_or_error = Core::System::stat(path);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode);
+}
+
+bool is_device(int fd)
+{
+    auto st_or_error = Core::System::fstat(fd);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode);
+}
+
+bool is_block_device(StringView path)
+{
+    auto st_or_error = Core::System::stat(path);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISBLK(st.st_mode);
+}
+
+bool is_block_device(int fd)
+{
+    auto st_or_error = Core::System::fstat(fd);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISBLK(st.st_mode);
+}
+
+bool is_char_device(StringView path)
+{
+    auto st_or_error = Core::System::stat(path);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISCHR(st.st_mode);
+}
+
+bool is_char_device(int fd)
+{
+    auto st_or_error = Core::System::fstat(fd);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISCHR(st.st_mode);
+}
+
+bool is_directory(StringView path)
+{
+    auto st_or_error = Core::System::stat(path);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISDIR(st.st_mode);
+}
+
+bool is_directory(int fd)
+{
+    auto st_or_error = Core::System::fstat(fd);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISDIR(st.st_mode);
+}
+
+bool is_link(StringView path)
+{
+    auto st_or_error = Core::System::lstat(path);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISLNK(st.st_mode);
+}
+
+bool is_link(int fd)
+{
+    auto st_or_error = Core::System::fstat(fd);
+    if (st_or_error.is_error())
+        return false;
+    auto st = st_or_error.release_value();
+    return S_ISLNK(st.st_mode);
+}
+
+static ErrorOr<String> get_duplicate_file_name(StringView path)
+{
+    int duplicate_count = 0;
+    LexicalPath lexical_path(path);
+    auto parent_path = LexicalPath::canonicalized_path(lexical_path.dirname());
+    auto basename = lexical_path.basename();
+    auto current_name = TRY(String::from_deprecated_string(LexicalPath::join(parent_path, basename).string()));
+
+    while (exists(current_name)) {
+        ++duplicate_count;
+        current_name = TRY(String::from_deprecated_string(LexicalPath::join(parent_path, TRY(String::formatted("{} ({})", basename, duplicate_count))).string()));
+    }
+
+    return current_name;
+}
+
+ErrorOr<void> copy_file(StringView destination_path, StringView source_path, struct stat const& source_stat, Core::File& source, PreserveMode preserve_mode)
+{
+    auto destination_or_error = Core::File::open(destination_path, Core::File::OpenMode::Write, 0666);
+    if (destination_or_error.is_error()) {
+        if (destination_or_error.error().code() != EISDIR)
+            return destination_or_error.release_error();
+
+        auto destination_dir_path = TRY(String::formatted("{}/{}", destination_path, LexicalPath::basename(source_path)));
+        destination_or_error = TRY(Core::File::open(destination_dir_path, Core::File::OpenMode::Write, 0666));
+    }
+    auto destination = destination_or_error.release_value();
+
+    if (source_stat.st_size > 0)
+        TRY(destination->truncate(source_stat.st_size));
+
+    while (true) {
+        auto bytes_read = TRY(source.read_until_eof());
+
+        if (bytes_read.is_empty())
+            break;
+
+        TRY(destination->write_until_depleted(bytes_read));
+    }
+
+    auto my_umask = umask(0);
+    umask(my_umask);
+    // NOTE: We don't copy the set-uid and set-gid bits unless requested.
+    if (!has_flag(preserve_mode, PreserveMode::Permissions))
+        my_umask |= 06000;
+
+    TRY(Core::System::fchmod(destination->fd(), source_stat.st_mode & ~my_umask));
+
+    if (has_flag(preserve_mode, PreserveMode::Ownership))
+        TRY(Core::System::fchown(destination->fd(), source_stat.st_uid, source_stat.st_gid));
+
+    if (has_flag(preserve_mode, PreserveMode::Timestamps)) {
+        struct timespec times[2] = {
+#ifdef AK_OS_MACOS
+            source_stat.st_atimespec,
+            source_stat.st_mtimespec,
+#else
+            source_stat.st_atim,
+            source_stat.st_mtim,
+#endif
+        };
+        TRY(Core::System::utimensat(AT_FDCWD, destination_path, times, 0));
+    }
+    return {};
+}
+
+ErrorOr<void> copy_directory(StringView destination_path, StringView source_path, struct stat const& source_stat, LinkMode link, PreserveMode preserve_mode)
+{
+    TRY(Core::System::mkdir(destination_path, 0755));
+
+    auto source_rp = TRY(real_path(source_path));
+    source_rp = TRY(String::formatted("{}/", source_rp));
+
+    auto destination_rp = TRY(real_path(destination_path));
+    destination_rp = TRY(String::formatted("{}/", destination_rp));
+
+    if (!destination_rp.is_empty() && destination_rp.starts_with_bytes(source_rp))
+        return Error::from_errno(EINVAL);
+
+    Core::DirIterator di(source_path, Core::DirIterator::SkipParentAndBaseDir);
+    if (di.has_error())
+        return di.error();
+
+    while (di.has_next()) {
+        auto filename = TRY(String::from_deprecated_string(di.next_path()));
+        TRY(copy_file_or_directory(
+            TRY(String::formatted("{}/{}", destination_path, filename)),
+            TRY(String::formatted("{}/{}", source_path, filename)),
+            RecursionMode::Allowed, link, AddDuplicateFileMarker::Yes, preserve_mode));
+    }
+
+    auto my_umask = umask(0);
+    umask(my_umask);
+
+    TRY(Core::System::chmod(destination_path, source_stat.st_mode & ~my_umask));
+
+    if (has_flag(preserve_mode, PreserveMode::Ownership))
+        TRY(Core::System::chown(destination_path, source_stat.st_uid, source_stat.st_gid));
+
+    if (has_flag(preserve_mode, PreserveMode::Timestamps)) {
+        struct timespec times[2] = {
+#ifdef AK_OS_MACOS
+            source_stat.st_atimespec,
+            source_stat.st_mtimespec,
+#else
+            source_stat.st_atim,
+            source_stat.st_mtim,
+#endif
+        };
+        TRY(Core::System::utimensat(AT_FDCWD, destination_path, times, 0));
+    }
+
+    return {};
+}
+
+ErrorOr<void> copy_file_or_directory(StringView destination_path, StringView source_path, RecursionMode recursion_mode, LinkMode link_mode, AddDuplicateFileMarker add_duplicate_file_marker, PreserveMode preserve_mode)
+{
+    String final_destination_path;
+    if (add_duplicate_file_marker == AddDuplicateFileMarker::Yes)
+        final_destination_path = TRY(get_duplicate_file_name(destination_path));
+    else
+        final_destination_path = TRY(String::from_utf8(destination_path));
+
+    auto source = TRY(Core::File::open(source_path, Core::File::OpenMode::Read));
+
+    auto source_stat = TRY(Core::System::fstat(source->fd()));
+
+    if (is_directory(source_path)) {
+        if (recursion_mode == RecursionMode::Disallowed) {
+            return Error::from_errno(EISDIR);
+        }
+
+        return copy_directory(final_destination_path, source_path, source_stat);
+    }
+
+    if (link_mode == LinkMode::Allowed)
+        return TRY(Core::System::link(source_path, final_destination_path));
+
+    return copy_file(final_destination_path, source_path, source_stat, *source, preserve_mode);
+}
+
+ErrorOr<void> remove(StringView path, RecursionMode mode)
+{
+    if (is_directory(path) && mode == RecursionMode::Allowed) {
+        auto di = Core::DirIterator(path, Core::DirIterator::SkipParentAndBaseDir);
+        if (di.has_error())
+            return di.error();
+
+        while (di.has_next())
+            TRY(remove(di.next_full_path(), RecursionMode::Allowed));
+
+        TRY(Core::System::rmdir(path));
+    } else {
+        TRY(Core::System::unlink(path));
+    }
+
+    return {};
+}
+
+ErrorOr<size_t> size(StringView path)
+{
+    auto st = TRY(Core::System::stat(path));
+    return st.st_size;
+}
+
+bool can_delete_or_move(StringView path)
+{
+    VERIFY(!path.is_empty());
+    auto directory = LexicalPath::dirname(path);
+    auto directory_has_write_access = !Core::System::access(directory, W_OK).is_error();
+    if (!directory_has_write_access)
+        return false;
+
+    auto stat_or_empty = [](StringView path) {
+        auto stat_or_error = Core::System::stat(path);
+        if (stat_or_error.is_error()) {
+            struct stat stat { };
+            return stat;
+        }
+        return stat_or_error.release_value();
+    };
+
+    auto directory_stat = stat_or_empty(directory);
+    bool is_directory_sticky = (directory_stat.st_mode & S_ISVTX) != 0;
+    if (!is_directory_sticky)
+        return true;
+
+    // Directory is sticky, only the file owner, directory owner, and root can modify (rename, remove) it.
+    auto user_id = geteuid();
+    return user_id == 0 || directory_stat.st_uid == user_id || stat_or_empty(path).st_uid == user_id;
+}
+
+ErrorOr<String> read_link(StringView link_path)
+{
+    return TRY(String::from_deprecated_string(TRY(Core::System::readlink(link_path))));
+}
+
+ErrorOr<void> link_file(StringView destination_path, StringView source_path)
+{
+    return TRY(Core::System::symlink(source_path, TRY(get_duplicate_file_name(destination_path))));
+}
+
+ErrorOr<String> resolve_executable_from_environment(StringView filename)
+{
+    if (filename.is_empty())
+        return Error::from_errno(ENOENT);
+
+    // Paths that aren't just a file name generally count as already resolved.
+    if (filename.contains('/')) {
+        TRY(Core::System::access(filename, X_OK));
+        return TRY(String::from_utf8(filename));
+    }
+
+    auto const* path_str = ::getenv("PATH");
+    StringView path;
+    if (path_str)
+        path = { path_str, strlen(path_str) };
+    if (path.is_empty())
+        path = DEFAULT_PATH_SV;
+
+    auto directories = path.split_view(':');
+
+    for (auto directory : directories) {
+        auto file = TRY(String::formatted("{}/{}", directory, filename));
+
+        if (!Core::System::access(file, X_OK).is_error())
+            return file;
+    }
+
+    return Error::from_errno(ENOENT);
+}
+
+bool looks_like_shared_library(StringView path)
+{
+    return path.ends_with(".so"sv) || path.contains(".so."sv);
+}
+
+}
diff --git a/Userland/Libraries/LibFileSystem/FileSystem.h b/Userland/Libraries/LibFileSystem/FileSystem.h
new file mode 100644
index 0000000000..41ba5862b8
--- /dev/null
+++ b/Userland/Libraries/LibFileSystem/FileSystem.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2023, Cameron Youell <cameronyouell@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Error.h>
+#include <AK/String.h>
+#include <AK/StringView.h>
+#include <LibCore/File.h>
+#include <sys/stat.h>
+
+namespace FileSystem {
+
+#define DEFAULT_PATH "/usr/local/sbin:/usr/local/bin:/usr/bin:/bin"
+#define DEFAULT_PATH_SV "/usr/local/sbin:/usr/local/bin:/usr/bin:/bin"sv
+
+ErrorOr<String> current_working_directory();
+ErrorOr<String> absolute_path(StringView path);
+ErrorOr<String> real_path(StringView path);
+
+bool exists(StringView path);
+bool exists(int fd);
+
+bool is_directory(StringView path);
+bool is_directory(int fd);
+
+bool is_device(StringView path);
+bool is_device(int fd);
+
+bool is_block_device(StringView path);
+bool is_block_device(int fd);
+
+bool is_char_device(StringView path);
+bool is_char_device(int fd);
+
+bool is_link(StringView path);
+bool is_link(int fd);
+
+enum class RecursionMode {
+    Allowed,
+    Disallowed
+};
+
+enum class LinkMode {
+    Allowed,
+    Disallowed
+};
+
+enum class AddDuplicateFileMarker {
+    Yes,
+    No,
+};
+
+enum class PreserveMode {
+    Nothing = 0,
+    Permissions = (1 << 0),
+    Ownership = (1 << 1),
+    Timestamps = (1 << 2),
+};
+AK_ENUM_BITWISE_OPERATORS(PreserveMode);
+
+ErrorOr<void> copy_file(StringView destination_path, StringView source_path, struct stat const& source_stat, Core::File& source, PreserveMode = PreserveMode::Nothing);
+ErrorOr<void> copy_directory(StringView destination_path, StringView source_path, struct stat const& source_stat, LinkMode = LinkMode::Disallowed, PreserveMode = PreserveMode::Nothing);
+ErrorOr<void> copy_file_or_directory(StringView destination_path, StringView source_path, RecursionMode = RecursionMode::Allowed, LinkMode = LinkMode::Disallowed, AddDuplicateFileMarker = AddDuplicateFileMarker::Yes, PreserveMode = PreserveMode::Nothing);
+ErrorOr<void> remove(StringView path, RecursionMode);
+ErrorOr<size_t> size(StringView path);
+bool can_delete_or_move(StringView path);
+
+ErrorOr<String> read_link(StringView link_path);
+ErrorOr<void> link_file(StringView destination_path, StringView source_path);
+
+ErrorOr<String> resolve_executable_from_environment(StringView filename);
+bool looks_like_shared_library(StringView path);
+
+}