Add realpath variants of the commands that return paths.

Closes #1670.

src/command_download.cc

@@ -655,6 +655,8 @@ initialize_command_download() {
   CMD2_DL("d.base_path.as_binary",            [](auto* download, auto) { return retrieve_d_base_path(download).object_as_binary(); });
   CMD2_DL("d.base_path.or_base64",            [](auto* download, auto) { return retrieve_d_base_path(download).object_utf8_or_base64(); });
   CMD2_DL("d.base_path.or_as_binary",         [](auto* download, auto) { return retrieve_d_base_path(download).object_utf8_or_as_binary(); });
+  CMD2_DL("d.base_path.realpath.or_empty",    [](auto* download, auto) { return resolve_path(retrieve_d_base_path(download).str()); });
+  CMD2_DL("d.base_path.realpath.or_throw",    [](auto* download, auto) { return resolve_path_or_throw(retrieve_d_base_path(download).str()); });
   CMD2_DL("d.base_filename",                  [](auto* download, auto) { return retrieve_d_base_filename(download).str(); });
   CMD2_DL("d.base_filename.hex",              [](auto* download, auto) { return retrieve_d_base_filename(download).object_hex(); });
   CMD2_DL("d.base_filename.base64",           [](auto* download, auto) { return retrieve_d_base_filename(download).object_base64(); });
@@ -771,6 +773,11 @@ initialize_command_download() {
   CMD2_DL_VAR_STRING_PUBLIC("d.tied_to_file", "rtorrent", "tied_to_file");
   CMD2_DL_VAR_STRING("d.loaded_file",  "rtorrent", "loaded_file");
 
+  CMD2_DL("d.tied_to_file.realpath.or_empty", [](auto* download, auto) { return resolve_path(rpc::convert_to_string(download_get_variable(download, "rtorrent", "tied_to_file"))); });
+  CMD2_DL("d.tied_to_file.realpath.or_throw", [](auto* download, auto) { return resolve_path_or_throw(rpc::convert_to_string(download_get_variable(download, "rtorrent", "tied_to_file"))); });
+  CMD2_DL("d.loaded_file.realpath.or_empty",  [](auto* download, auto) { return resolve_path(rpc::convert_to_string(download_get_variable(download, "rtorrent", "loaded_file"))); });
+  CMD2_DL("d.loaded_file.realpath.or_throw",  [](auto* download, auto) { return resolve_path_or_throw(rpc::convert_to_string(download_get_variable(download, "rtorrent", "loaded_file"))); });
+
   // The "state_changed" variable is required to be a valid unix time
   // value, it indicates the last time the torrent changed its state,
   // resume/pause.
@@ -878,6 +885,8 @@ initialize_command_download() {
   CMD2_DL_VALUE_V ("d.tracker.send_scrape",           [](auto download, uint64_t arg) { download->tracker_controller().scrape_request(arg); });
 
   CMD2_DL         ("d.directory",          CMD2_ON_FL(root_dir));
+  CMD2_DL         ("d.directory.realpath.or_empty", [](auto* download, auto) { return resolve_path(download->file_list()->root_dir()); });
+  CMD2_DL         ("d.directory.realpath.or_throw", [](auto* download, auto) { return resolve_path_or_throw(download->file_list()->root_dir()); });
   CMD2_DL_STRING_V("d.directory.set",      std::bind(&apply_d_directory, std::placeholders::_1, std::placeholders::_2));
   CMD2_DL         ("d.directory_base",     CMD2_ON_FL(root_dir));
   CMD2_DL_STRING_V("d.directory_base.set", std::bind(&core::Download::set_root_directory, std::placeholders::_1, std::placeholders::_2));
@@ -912,6 +921,14 @@ initialize_command_download() {
   rpc::rpc.mark_safe("d.local_id_html");
   rpc::rpc.mark_safe("d.bitfield");
   rpc::rpc.mark_safe("d.base_path");
+  rpc::rpc.mark_safe("d.base_path.realpath.or_empty");
+  rpc::rpc.mark_safe("d.base_path.realpath.or_throw");
+  rpc::rpc.mark_safe("d.directory.realpath.or_empty");
+  rpc::rpc.mark_safe("d.directory.realpath.or_throw");
+  rpc::rpc.mark_safe("d.tied_to_file.realpath.or_empty");
+  rpc::rpc.mark_safe("d.tied_to_file.realpath.or_throw");
+  rpc::rpc.mark_safe("d.loaded_file.realpath.or_empty");
+  rpc::rpc.mark_safe("d.loaded_file.realpath.or_throw");
   rpc::rpc.mark_safe("d.base_path.hex");
   rpc::rpc.mark_safe("d.base_path.base64");
   rpc::rpc.mark_safe("d.base_path.base64_as_binary");

src/command_file.cc

@@ -116,6 +116,8 @@ initialize_command_file() {
   CMD2_FILE("f.frozen_path.as_binary",            [](auto* file, auto)   { return file->frozen_path().object_as_binary(); });
   CMD2_FILE("f.frozen_path.or_base64",            [](auto* file, auto)   { return file->frozen_path().object_utf8_or_base64(); });
   CMD2_FILE("f.frozen_path.or_as_binary",         [](auto* file, auto)   { return file->frozen_path().object_utf8_or_as_binary(); });
+  CMD2_FILE("f.frozen_path.realpath.or_empty",    [](auto* file, auto)   { return resolve_path(file->frozen_path().str()); });
+  CMD2_FILE("f.frozen_path.realpath.or_throw",    [](auto* file, auto)   { return resolve_path_or_throw(file->frozen_path().str()); });
 
   CMD2_FILE("f.match_depth_prev",       std::bind(&torrent::File::match_depth_prev, std::placeholders::_1));
   CMD2_FILE("f.match_depth_next",       std::bind(&torrent::File::match_depth_next, std::placeholders::_1));
@@ -129,6 +131,8 @@ initialize_command_file() {
   rpc::rpc.mark_safe("f.path_components");
   rpc::rpc.mark_safe("f.path_depth");
   rpc::rpc.mark_safe("f.frozen_path");
+  rpc::rpc.mark_safe("f.frozen_path.realpath.or_empty");
+  rpc::rpc.mark_safe("f.frozen_path.realpath.or_throw");
   rpc::rpc.mark_safe("f.frozen_path.hex");
   rpc::rpc.mark_safe("f.frozen_path.base64");
   rpc::rpc.mark_safe("f.frozen_path.base64_as_binary");

src/command_local.cc

@@ -296,9 +296,13 @@ initialize_command_local() {
   CMD_VAR_BOOL    ("pieces.hash.on_completion",       true);
 
   CMD_VAR_STRING  ("directory.default",               "./");
+  CMD_ANY         ("directory.default.realpath.or_empty", [](auto, auto)    { return resolve_path(rpc::call_command_string("directory.default")); });
+  CMD_ANY         ("directory.default.realpath.or_throw", [](auto, auto)    { return resolve_path_or_throw(rpc::call_command_string("directory.default")); });
 
   CMD_VAR_STRING  ("session.name",                    "");
   CMD_ANY         ("session.path",                    [](auto, auto)        { return session_thread::manager()->path(); });
+  CMD_ANY         ("session.path.realpath.or_empty",  [](auto, auto)        { return resolve_path(session_thread::manager()->path()); });
+  CMD_ANY         ("session.path.realpath.or_throw",  [](auto, auto)        { return resolve_path_or_throw(session_thread::manager()->path()); });
   CMD_ANY_STRING_V("session.path.set",                [](auto, auto& str)   { return session_thread::manager()->set_path(str); });
   CMD_ANY         ("session.use_lock",                [](auto, auto)        { return session_thread::manager()->use_lock(); });
   CMD_ANY_VALUE_V ("session.use_lock.set",            [](auto, auto& value) { return session_thread::manager()->set_use_lock(value); });
@@ -372,6 +376,10 @@ initialize_command_local() {
 
   rpc::rpc.mark_safe("directory.default");
   rpc::rpc.mark_safe("session.path");
+  rpc::rpc.mark_safe("session.path.realpath.or_empty");
+  rpc::rpc.mark_safe("session.path.realpath.or_throw");
+  rpc::rpc.mark_safe("directory.default.realpath.or_empty");
+  rpc::rpc.mark_safe("directory.default.realpath.or_throw");
   rpc::rpc.mark_safe("session.use_lock");
   rpc::rpc.mark_safe("session.on_completion");
 

src/globals.cc

@@ -3,6 +3,7 @@
 #include "globals.h"
 
 #include <cstdlib>
+#include <stdlib.h>
 #include <torrent/exceptions.h>
 
 rpc::ip_table_list ip_tables;
@@ -28,3 +29,32 @@ expand_path(const std::string& path) {
 
   return path;
 }
+
+// Resolves a path to a canonical one with no symlinks or relative components,
+// so it can safely be handed to an external script. Returns an empty string if
+// the path does not name an existing file or directory.
+std::string
+resolve_path(const std::string& path) {
+  if (path.empty())
+    return std::string();
+
+  char* resolved = ::realpath(expand_path(path).c_str(), nullptr);
+
+  if (resolved == nullptr)
+    return std::string();
+
+  std::string result(resolved);
+  std::free(resolved);
+
+  return result;
+}
+
+std::string
+resolve_path_or_throw(const std::string& path) {
+  auto result = resolve_path(path);
+
+  if (result.empty())
+    throw torrent::input_error("Could not resolve path: '" + path + "'.");
+
+  return result;
+}

src/globals.h

@@ -11,6 +11,8 @@ extern rpc::ip_table_list ip_tables;
 extern Control*           control;
 
 std::string expand_path(const std::string& path);
+std::string resolve_path(const std::string& path);
+std::string resolve_path_or_throw(const std::string& path);
 
 namespace rpc {
 class SCgi;

test/Makefile.am

@@ -51,6 +51,8 @@ rtorrent_Test_Src_SOURCES = $(rtorrent_Test_Common) \
 	src/test_command_dynamic.h \
 	src/test_command_local.cc \
 	src/test_command_local.h \
+	src/test_command_path.cc \
+	src/test_command_path.h \
 	src/test_command_string.cc \
 	src/test_command_string.h \
 	src/test_watch_ready_queue.cc \

test/src/test_command_path.cc

@@ -0,0 +1,116 @@
+#include "config.h"
+
+#include "test/src/test_command_path.h"
+
+#include <cstdlib>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <torrent/exceptions.h>
+#include <torrent/torrent.h>
+
+#include "control.h"
+#include "globals.h"
+#include "rpc/parse_commands.h"
+
+CPPUNIT_TEST_SUITE_REGISTRATION(TestCommandPath);
+
+void initialize_command_local();
+
+void
+TestCommandPath::setUp() {
+  char temp_dir[] = "/tmp/rtorrent_test_path_XXXXXX";
+
+  CPPUNIT_ASSERT(mkdtemp(temp_dir) != nullptr);
+
+  // The temporary directory itself may sit behind a symlink, as /tmp does on
+  // macOS, so resolve it up front to keep the expected values exact.
+  m_temp_dir = resolve_path(temp_dir);
+
+  CPPUNIT_ASSERT(!m_temp_dir.empty());
+  CPPUNIT_ASSERT_EQUAL(0, mkdir((m_temp_dir + "/data").c_str(), 0755));
+  CPPUNIT_ASSERT_EQUAL(0, symlink((m_temp_dir + "/data").c_str(), (m_temp_dir + "/link").c_str()));
+}
+
+void
+TestCommandPath::tearDown() {
+  unlink((m_temp_dir + "/link").c_str());
+  rmdir((m_temp_dir + "/data").c_str());
+  rmdir(m_temp_dir.c_str());
+}
+
+void
+TestCommandPath::test_resolves_symlink() {
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", resolve_path(m_temp_dir + "/link"));
+
+  // A path that lies below a symlinked directory is resolved as well.
+  CPPUNIT_ASSERT_EQUAL(0, mkdir((m_temp_dir + "/data/below").c_str(), 0755));
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data/below", resolve_path(m_temp_dir + "/link/below"));
+  rmdir((m_temp_dir + "/data/below").c_str());
+}
+
+void
+TestCommandPath::test_removes_relative_components() {
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir, resolve_path(m_temp_dir + "/data/.."));
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", resolve_path(m_temp_dir + "/./data"));
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", resolve_path(m_temp_dir + "/data/"));
+
+  // Trailing slashes and duplicated separators collapse.
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", resolve_path(m_temp_dir + "//data//"));
+}
+
+void
+TestCommandPath::test_expands_tilde() {
+  const char* home = std::getenv("HOME");
+
+  if (home == nullptr || *home == '\0')
+    return;
+
+  CPPUNIT_ASSERT_EQUAL(resolve_path(home), resolve_path("~"));
+  CPPUNIT_ASSERT_THROW(resolve_path("~root/somewhere"), torrent::input_error);
+}
+
+void
+TestCommandPath::test_missing_path_throws() {
+  CPPUNIT_ASSERT_THROW(resolve_path_or_throw(""), torrent::input_error);
+  CPPUNIT_ASSERT_THROW(resolve_path_or_throw(m_temp_dir + "/does_not_exist"), torrent::input_error);
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", resolve_path_or_throw(m_temp_dir + "/link"));
+}
+
+void
+TestCommandPath::test_missing_path_is_empty() {
+  CPPUNIT_ASSERT_EQUAL(std::string(), resolve_path(""));
+  CPPUNIT_ASSERT_EQUAL(std::string(), resolve_path(m_temp_dir + "/does_not_exist"));
+  CPPUNIT_ASSERT_EQUAL(std::string(), resolve_path(m_temp_dir + "/does_not_exist/below"));
+
+  // A dangling symlink does not name an existing path either.
+  CPPUNIT_ASSERT_EQUAL(0, symlink((m_temp_dir + "/gone").c_str(), (m_temp_dir + "/dangling").c_str()));
+  CPPUNIT_ASSERT_EQUAL(std::string(), resolve_path(m_temp_dir + "/dangling"));
+  unlink((m_temp_dir + "/dangling").c_str());
+}
+
+void
+TestCommandPath::test_commands() {
+  torrent::initialize_main_thread();
+  torrent::initialize();
+
+  if (control == nullptr)
+    control = new Control;
+
+  if (!rpc::commands.has("directory.default.realpath.or_empty"))
+    initialize_command_local();
+
+  rpc::commands.call_command("directory.default.set", m_temp_dir + "/link");
+
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/link", rpc::commands.call_command("directory.default", torrent::Object()).as_string());
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", rpc::commands.call_command("directory.default.realpath.or_empty", torrent::Object()).as_string());
+  CPPUNIT_ASSERT_EQUAL(m_temp_dir + "/data", rpc::commands.call_command("directory.default.realpath.or_throw", torrent::Object()).as_string());
+
+  // A directory that has not been created yet resolves to nothing, and the
+  // or_throw variant reports it instead.
+  rpc::commands.call_command("directory.default.set", m_temp_dir + "/missing");
+
+  CPPUNIT_ASSERT_EQUAL(std::string(), rpc::commands.call_command("directory.default.realpath.or_empty", torrent::Object()).as_string());
+  CPPUNIT_ASSERT_THROW(rpc::commands.call_command("directory.default.realpath.or_throw", torrent::Object()), torrent::input_error);
+
+  torrent::cleanup();
+}

test/src/test_command_path.h

@@ -0,0 +1,30 @@
+#include "test/helpers/test_fixture.h"
+
+#include <string>
+
+class TestCommandPath : public test_fixture {
+  CPPUNIT_TEST_SUITE(TestCommandPath);
+
+  CPPUNIT_TEST(test_resolves_symlink);
+  CPPUNIT_TEST(test_removes_relative_components);
+  CPPUNIT_TEST(test_expands_tilde);
+  CPPUNIT_TEST(test_missing_path_is_empty);
+  CPPUNIT_TEST(test_missing_path_throws);
+  CPPUNIT_TEST(test_commands);
+
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+  void setUp();
+  void tearDown();
+
+  void test_resolves_symlink();
+  void test_removes_relative_components();
+  void test_expands_tilde();
+  void test_missing_path_is_empty();
+  void test_missing_path_throws();
+  void test_commands();
+
+private:
+  std::string m_temp_dir;
+};