Answer an oversized RPC response with a fault

Cap XML-RPC and JSON-RPC output at the SCGI response limit before handing it over.

configure.ac

@@ -1,6 +1,6 @@
 m4_pattern_allow([PKG_CHECK_EXISTS])
 
-AC_INIT([rtorrent],[0.16.22],[sundell.software@gmail.com])
+AC_INIT([rtorrent],[0.16.23],[sundell.software@gmail.com])
 
 AC_CONFIG_HEADERS([config.h])
 AC_CONFIG_MACRO_DIRS([scripts])
@@ -14,7 +14,7 @@ AX_CXX_COMPILE_STDCXX(20, noext, mandatory)
 
 PKG_PROG_PKG_CONFIG
 
-AC_DEFINE([API_VERSION], [26], [api version])
+AC_DEFINE([API_VERSION], [27], [api version])
 
 RAK_CHECK_CFLAGS
 RAK_CHECK_CXXFLAGS
@@ -49,7 +49,7 @@ fi
 
 PKG_CHECK_MODULES([CPPUNIT], [cppunit],, [no_cppunit="yes"])
 PKG_CHECK_MODULES([ZLIB], [zlib])
-PKG_CHECK_MODULES([DEPENDENCIES], [libtorrent >= 0.16.22])
+PKG_CHECK_MODULES([DEPENDENCIES], [libtorrent >= 0.16.23])
 
 AC_LANG_PUSH(C++)
 TORRENT_WITH_XMLRPC_C

src/command_download.cc

@@ -431,6 +431,9 @@ p_call_target(const torrent::Object::list_type& args) {
   const std::string& peer_id = itr++->as_string();
   const std::string& command_key = itr++->as_string();
 
+  if (download == nullptr)
+    throw torrent::input_error("invalid parameters: info-hash not found");
+
   torrent::HashString hash;
 
   if (peer_id.size() != 40)

src/command_dynamic.cc

@@ -157,7 +157,7 @@ system_method_insert_object(const torrent::Object::list_type& args, int flags) {
     torrent::Object             valueList     = torrent::Object::create_list();
     torrent::Object::list_type& valueListType = valueList.as_list();
 
-    if ((itrArgs)->is_list())
+    if (itrArgs != args.end() && (itrArgs)->is_list())
       valueListType = (itrArgs)->as_list();
 
     control->object_storage()->insert_str(raw_key, valueList, flags);

src/command_ip.cc

@@ -319,6 +319,11 @@ apply_ipv4_filter_load(const torrent::Object::list_type& args) {
       ipv4_filter_parse(buffer, value);
     }
 
+    if (file.fail() && !file.eof()) {
+      lineNumber++;
+      throw torrent::input_error("Exceeded max line length.");
+    }
+
   } catch (torrent::input_error& e) {
     snprintf(buffer, 2048, "Error in ip filter file: %s:%u: %s", filename.c_str(), lineNumber, e.what());
 

src/command_logging.cc

@@ -122,7 +122,10 @@ log_vmmap_dump(const std::string& str) {
     fprintf(log_file, "%8p-%8p [%5llxk]\n", all_mapping.ptr, (char*)all_mapping.ptr + all_mapping.length, (long long unsigned int)(all_mapping.length / 1024));
   }
 
-  fclose(log_file);
+  // The buffered output only reaches the kernel here.
+  if (fclose(log_file) != 0)
+    throw torrent::input_error("Could not write log file: " + str);
+
   return torrent::Object();
 }
 

src/command_network.cc

@@ -374,25 +374,31 @@ initialize_command_network() {
   CMD_ANY_STRING  ("network.tos.set",                        [](auto, auto& str)             { return apply_tos(str); });
 
   CMD_ANY         ("network.bind_address",                   [nw_config](auto, auto)         { return nw_config->bind_address_best_match_str(); });
-  CMD_ANY_STRING_V("network.bind_address.set",               [nw_config](auto, auto& str)    { return nw_config->set_bind_address_str(str); });
+  CMD_ANY_STRING_V("network.bind_address.set",               [nw_config](auto, auto& str)    { return nw_config->set_bind_address(str); });
   CMD_ANY         ("network.bind_address.ipv4",              [nw_config](auto, auto)         { return nw_config->bind_inet_address_str(); });
-  CMD_ANY_STRING_V("network.bind_address.ipv4.set",          [nw_config](auto, auto& str)    { return nw_config->set_bind_inet_address_str(str); });
+  CMD_ANY_STRING_V("network.bind_address.ipv4.set",          [nw_config](auto, auto& str)    { return nw_config->set_bind_inet_address(str); });
   CMD_ANY         ("network.bind_address.ipv6",              [nw_config](auto, auto)         { return nw_config->bind_inet6_address_str(); });
-  CMD_ANY_STRING_V("network.bind_address.ipv6.set",          [nw_config](auto, auto& str)    { return nw_config->set_bind_inet6_address_str(str); });
+  CMD_ANY_STRING_V("network.bind_address.ipv6.set",          [nw_config](auto, auto& str)    { return nw_config->set_bind_inet6_address(str); });
+
+  CMD_ANY_STRING_V("network.bind_device.set",                [nw_config](auto, auto& str)    { return nw_config->set_bind_device_name(str); });
+  CMD_ANY         ("network.bind_device.ipv4",               [nw_config](auto, auto)         { return nw_config->bind_inet_device_name(); });
+  CMD_ANY_STRING_V("network.bind_device.ipv4.set",           [nw_config](auto, auto& str)    { return nw_config->set_bind_inet_device_name(str); });
+  CMD_ANY         ("network.bind_device.ipv6",               [nw_config](auto, auto)         { return nw_config->bind_inet6_device_name(); });
+  CMD_ANY_STRING_V("network.bind_device.ipv6.set",           [nw_config](auto, auto& str)    { return nw_config->set_bind_inet6_device_name(str); });
 
   CMD_ANY         ("network.local_address",                  [nw_config](auto, auto)         { return nw_config->local_address_best_match_str(); });
-  CMD_ANY_STRING_V("network.local_address.set",              [nw_config](auto, auto& str)    { return nw_config->set_local_address_str(str); });
+  CMD_ANY_STRING_V("network.local_address.set",              [nw_config](auto, auto& str)    { return nw_config->set_local_address(str); });
   CMD_ANY         ("network.local_address.ipv4",             [nw_config](auto, auto)         { return nw_config->local_inet_address_str(); });
-  CMD_ANY_STRING_V("network.local_address.ipv4.set",         [nw_config](auto, auto& str)    { return nw_config->set_local_inet_address_str(str); });
+  CMD_ANY_STRING_V("network.local_address.ipv4.set",         [nw_config](auto, auto& str)    { return nw_config->set_local_inet_address(str); });
   CMD_ANY         ("network.local_address.ipv6",             [nw_config](auto, auto)         { return nw_config->local_inet6_address_str(); });
-  CMD_ANY_STRING_V("network.local_address.ipv6.set",         [nw_config](auto, auto& str)    { return nw_config->set_local_inet6_address_str(str); });
+  CMD_ANY_STRING_V("network.local_address.ipv6.set",         [nw_config](auto, auto& str)    { return nw_config->set_local_inet6_address(str); });
 
   CMD_ANY         ("network.local_port",                     [nw_config](auto, auto)         { return nw_config->local_port_best_match(); });
-  CMD_ANY_VALUE_V ("network.local_port.set",                 [nw_config](auto, auto& value) { return nw_config->set_local_port(checked_local_port_value(value, "local")); });
+  CMD_ANY_VALUE_V ("network.local_port.set",                 [nw_config](auto, auto& value)  { return nw_config->set_local_port(checked_local_port_value(value, "local")); });
   CMD_ANY         ("network.local_port.ipv4",                [nw_config](auto, auto)         { return nw_config->local_inet_port(); });
-  CMD_ANY_VALUE_V ("network.local_port.ipv4.set",            [nw_config](auto, auto& value) { return nw_config->set_local_inet_port(checked_local_port_value(value, "local ipv4")); });
+  CMD_ANY_VALUE_V ("network.local_port.ipv4.set",            [nw_config](auto, auto& value)  { return nw_config->set_local_inet_port(checked_local_port_value(value, "local ipv4")); });
   CMD_ANY         ("network.local_port.ipv6",                [nw_config](auto, auto)         { return nw_config->local_inet6_port(); });
-  CMD_ANY_VALUE_V ("network.local_port.ipv6.set",            [nw_config](auto, auto& value) { return nw_config->set_local_inet6_port(checked_local_port_value(value, "local ipv6")); });
+  CMD_ANY_VALUE_V ("network.local_port.ipv6.set",            [nw_config](auto, auto& value)  { return nw_config->set_local_inet6_port(checked_local_port_value(value, "local ipv6")); });
 
   CMD_ANY         ("network.proxy.global",                   [](auto, auto)                  { return torrent::runtime::proxy_manager()->proxy_url(); });
   CMD_ANY_STRING_V("network.proxy.global.set",               [](auto, auto& str)             { return torrent::runtime::proxy_manager()->set_proxy_url(str); });

src/command_throttle.cc

@@ -1,6 +1,7 @@
 #include "config.h"
 
 #include <cstdio>
+#include <limits>
 #include <torrent/throttle.h>
 #include <torrent/rate.h>
 #include <torrent/download/resource_manager.h>
@@ -83,11 +84,16 @@ apply_throttle(const torrent::Object::list_type& args, bool up) {
     throw torrent::input_error("Missing throttle rate for '" + name + "'.");
 
   int64_t rate;
-  rpc::parse_whole_value_nothrow(arg_itr->as_string().c_str(), &rate);
+
+  if (!rpc::parse_whole_value_nothrow(arg_itr->as_string().c_str(), &rate))
+    throw torrent::input_error("Invalid throttle rate for '" + name + "'.");
 
   if (rate < 0)
     throw torrent::input_error("Throttle rate must be non-negative.");
 
+  if (rate > (std::numeric_limits<int64_t>::max() >> 10))
+    throw torrent::input_error("Throttle rate is too large.");
+
   auto itr = control->core()->throttles().find(name);
 
   if (itr == control->core()->throttles().end())

src/core/dht_manager.cc

@@ -132,11 +132,12 @@ DhtManager::save_dht_cache() {
   torrent::Object cache = torrent::Object::create_map();
   cache_file << *torrent::runtime::network_manager()->dht_controller()->store_cache(&cache);
 
+  // The data only reaches the kernel here, so this is where a full disk is seen.
+  cache_file.close();
+
   if (!cache_file.good())
     return;
 
-  cache_file.close();
-
   ::rename(filename_tmp.c_str(), filename.c_str());
 }
 

src/core/download_list.cc

@@ -301,7 +301,7 @@ DownloadList::set_state_stopped(Download* download) {
 void
 DownloadList::update_paused_state(Download* download) {
   rpc::call_command("d.state_changed.set", torrent::this_thread::cached_seconds().count(), rpc::make_target(download));
-  rpc::call_command("d.state_counter.set", rpc::call_command_value("d.state_counter", rpc::make_target(download)), rpc::make_target(download));
+  rpc::call_command("d.state_counter.set", rpc::call_command_value("d.state_counter", rpc::make_target(download)) + 1, rpc::make_target(download));
 
   // If initial seeding is complete, don't try it again when restarting.
   if (download->is_done() &&
@@ -726,11 +726,10 @@ DownloadList::process_meta_download(Download* download) {
     return;
   }
 
-  torrent::Object* bencode = new torrent::Object(torrent::Object::create_map());
+  auto bencode = std::make_unique<torrent::Object>(torrent::Object::create_map());
   file >> bencode->insert_key("info", torrent::Object());
 
   if (file.fail()) {
-    delete bencode;
     lt_log_print(torrent::LOG_TORRENT_ERROR, "Could not create download, the input is not a valid torrent.");
     return;
   }
@@ -746,7 +745,7 @@ DownloadList::process_meta_download(Download* download) {
 
   erase_ptr(download);
 
-  control->core()->try_create_download_from_meta_download(bencode, metafile);
+  control->core()->try_create_download_from_meta_download(std::move(bencode), metafile);
 }
 
 }

src/core/manager.cc

@@ -195,14 +195,14 @@ Manager::try_create_download(const std::string& uri, int flags, const command_li
     return;
 
   // Adding download.
-  DownloadFactory* f = new DownloadFactory(this);
+  auto f = std::make_unique<DownloadFactory>(this);
 
   f->variables()["tied_to_file"] = (int64_t)(bool)(flags & create_tied);
   f->commands().insert(f->commands().end(), commands.begin(), commands.end());
 
   f->set_start(flags & create_start);
   f->set_print_log(!(flags & create_quiet));
-  f->slot_finished([f]() { delete f; });
+  f->slot_finished([factory = f.get()]() { delete factory; });
 
   if (is_data_uri(uri)) {
     // Allow the use of data URIs, primarily for JSON-RPC which
@@ -216,10 +216,13 @@ Manager::try_create_download(const std::string& uri, int flags, const command_li
   }
 
   f->commit();
+
+  // From here the finished slot deletes it.
+  f.release();
 }
 
 void
-Manager::try_create_download_from_meta_download(torrent::Object* bencode, const std::string& metafile) {
+Manager::try_create_download_from_meta_download(std::unique_ptr<torrent::Object> bencode, const std::string& metafile) {
   DownloadFactory* f = new DownloadFactory(this);
 
   f->variables()["tied_to_file"] = (int64_t)true;

src/core/manager.h

@@ -76,7 +76,7 @@ public:
   // Temporary, find a better place for this.
   void                try_create_download(const std::string& uri, int flags, const command_list_type& commands);
   void                try_create_download_expand(const std::string& uri, int flags, command_list_type commands = command_list_type());
-  void                try_create_download_from_meta_download(torrent::Object* bencode, const std::string& metafile);
+  void                try_create_download_from_meta_download(std::unique_ptr<torrent::Object> bencode, const std::string& metafile);
 
 private:
   void                create_http(const std::string& uri);

src/core/view.cc

@@ -216,7 +216,7 @@ View::set_not_visible(Download* download) {
 
 void
 View::next_focus(unsigned int i) {
-  if (empty())
+  if (empty_visible())
     return;
 
   // If at the boundary, roll over
@@ -239,7 +239,7 @@ View::next_focus(unsigned int i) {
 
 void
 View::prev_focus(unsigned int i) {
-  if (empty())
+  if (empty_visible())
     return;
 
   // If at the boundary, roll over
@@ -301,7 +301,7 @@ View::filter() {
     std::for_each(changed.begin(), splitChanged, [this](const auto& d) { rpc::call_object_d_nothrow(m_event_removed, d.get()); });
 
   if (!m_event_added.is_empty())
-    std::for_each(changed.begin(), splitChanged, [this](const auto& d) { rpc::call_object_d_nothrow(m_event_added, d.get()); });
+    std::for_each(splitChanged, changed.end(), [this](const auto& d) { rpc::call_object_d_nothrow(m_event_added, d.get()); });
 
   emit_changed();
 }

src/display/window_file_list.cc

@@ -25,7 +25,10 @@ WindowFileList::WindowFileList(const ui::ElementFileList* element) :
 // Convert std::string to std::wstring of given width (in screen positions),
 // taking into account that some characters may be occupying two screen positions.
 std::wstring
-wstring_width(const std::string& i_str, [[maybe_unused]] int width) {
+wstring_width(const std::string& i_str, int width) {
+  if (width < 0)
+    width = 0;
+
   std::wstring result(width + 1, L' ');
   size_t length = std::mbstowcs(result.data(), i_str.c_str(), width);
 

src/rpc/command_scheduler.cc

@@ -61,14 +61,20 @@ CommandScheduler::call_item(value_type item) {
   // Remove the item before calling the command if it should be
   // removed.
 
+  std::string key = item->key();
+
   try {
     rpc::call_object(item->command());
 
   } catch (torrent::input_error& e) {
     if (m_slotErrorMessage)
-      m_slotErrorMessage("Scheduled command failed: " + item->key() + ": " + e.what());
+      m_slotErrorMessage("Scheduled command failed: " + key + ": " + e.what());
   }
 
+  // The command is allowed to erase or replace this item, which deletes it.
+  if (std::find(begin(), end(), item) == end())
+    return;
+
   // Still schedule if we caught a torrrent::input_error?
   auto next = item->next_time_scheduled();
 

src/rpc/jsonrpc.cc

@@ -13,6 +13,7 @@
 #include "rpc/command_map.h"
 #include "rpc/nlohmann/json.h"
 #include "rpc/parse_commands.h"
+#include "rpc/scgi_task.h"
 #include "torrent/exceptions.h"
 #include "torrent/object.h"
 #include "utils/functional.h"
@@ -264,6 +265,13 @@ JsonRpc::process(const char* in_buffer, uint32_t length, slot_write callback) {
 
     std::string response_str = response.dump();
 
+    if (response_str.size() > SCgiTask::max_response_size) {
+      const auto& id = response.is_object() && response.contains("id") ? response["id"] : json(nullptr);
+      auto err_str = json_error(JSONRPC_INTERNAL_ERROR, "response size exceeds maximum RPC limit", id).dump();
+
+      return callback(err_str.c_str(), err_str.size());
+    }
+
     return callback(response_str.c_str(), response_str.size());
 
   } catch (json::exception& e) {

src/rpc/object_storage.cc

@@ -64,8 +64,12 @@ object_storage::insert(const char* key_data, uint32_t key_size, const torrent::O
   if (std::find(key_data, key_data + key_size, '\0') != key_data + key_size)
     throw torrent::input_error("Found nul-char in string.");
 
-  // Check for size > key_size.
-  // Check for empty string.
+  // key_type turns a key this long into the empty key.
+  if (key_size >= object_storage::key_size)
+    throw torrent::input_error("Key is too long.");
+
+  if (key_size == 0)
+    throw torrent::input_error("Key is empty.");
 
   bool use_raw = false;
   torrent::Object object;

src/rpc/parse_commands.cc

@@ -181,6 +181,11 @@ parse_command_file(const std::string& path) {
       getCount = 0;
     }
 
+    if (file.fail() && !file.eof()) {
+      lineNumber++;
+      throw torrent::input_error("Exceeded max line length.");
+    }
+
   } catch (torrent::input_error& e) {
     snprintf(buffer, 2048, "Error in option file: %s:%u: %s", path.c_str(), lineNumber, e.what());
 

src/rpc/scgi_task.cc

@@ -93,7 +93,8 @@ SCgiTask::close() {
   // The callbacks are guaranteed to be finished/canceled at this point.
   auto lock = std::lock_guard<std::mutex>(m_result_mutex);
 
-  m_buffer.clear();
+  // clear() would keep the capacity, and the task is pooled for the lifetime of the process.
+  std::vector<char>().swap(m_buffer);
 }
 
 void
@@ -404,7 +405,7 @@ void
 SCgiTask::receive_write(const char* buffer, uint32_t length) {
   assert(torrent::this_thread::thread() == torrent::main_thread::thread());
 
-  if (buffer == nullptr || length > (100 << 20))
+  if (buffer == nullptr || length > max_response_size)
     throw torrent::internal_error("SCgiTask::receive_write(...) received bad input.");
 
   // Main thread callback already locked this mutex.

src/rpc/scgi_task.h

@@ -2,6 +2,7 @@
 #define RTORRENT_RPC_SCGI_TASK_H
 
 #include <chrono>
+#include <cstdint>
 #include <memory>
 #include <mutex>
 #include <vector>
@@ -18,6 +19,8 @@ public:
   static constexpr int max_header_size     = 2000;
   static constexpr int max_content_size    = (1 << 26);
 
+  static constexpr uint32_t max_response_size = (100 << 20);
+
   static constexpr auto timeout_request = std::chrono::seconds(60);
 
   enum ContentType { XML, JSON };

src/rpc/xmlrpc_c.cc

@@ -27,11 +27,11 @@ public:
   virtual ~xmlrpc_error_c() throw() {}
 
   virtual int         type() const throw() { return m_type; }
-  virtual const char* what() const throw() { return m_msg; }
+  virtual const char* what() const throw() { return m_msg.c_str(); }
 
 private:
   int                 m_type;
-  const char*         m_msg;
+  std::string         m_msg;
 };
 
 torrent::Object xmlrpc_to_object(xmlrpc_env* env, xmlrpc_value* value, int call_type = 0, rpc::target_type* target = NULL, std::function<void()>* deleter = NULL);
@@ -44,10 +44,9 @@ xmlrpc_list_entry_to_object(xmlrpc_env* env, xmlrpc_value* src, int index) {
   if (env->fault_occurred)
     throw xmlrpc_error_c(env);
 
-  torrent::Object obj = xmlrpc_to_object(env, tmp);
-  xmlrpc_DECREF(tmp);
+  utils::scope_guard guard([tmp]() { xmlrpc_DECREF(tmp); });
 
-  return obj;
+  return xmlrpc_to_object(env, tmp);
 }
 
 int64_t
@@ -213,11 +212,11 @@ xmlrpc_to_object(xmlrpc_env* env, xmlrpc_value* value, int call_type, rpc::targe
       if (env->fault_occurred)
         throw xmlrpc_error_c(env);
 
+      utils::scope_guard guard([tmp]() { xmlrpc_DECREF(tmp); });
+
       if (target != nullptr)
         std::tie(*target, *deleter) = xmlrpc_to_target(env, tmp, call_type);
 
-      xmlrpc_DECREF(tmp);
-
       if (env->fault_occurred)
         throw xmlrpc_error_c(env);
 

src/rpc/xmlrpc_tinyxml2.cc

@@ -19,6 +19,7 @@
 #include "rpc/tinyxml2/tinyxml2.h"
 #include "rpc/rpc_manager.h"
 #include "utils/base64.h"
+#include "utils/functional.h"
 #include "xmlrpc.h"
 
 namespace rpc {
@@ -258,6 +259,8 @@ execute_command(std::string method_name, const tinyxml2::XMLElement* params_elem
   torrent::Object             params_raw = torrent::Object::create_list();
   torrent::Object::list_type& params     = params_raw.as_list();
   rpc::target_type            target     = rpc::make_target();
+  std::function<void()>       deleter    = []() {};
+  utils::scope_guard          guard([&deleter]() { deleter(); });
 
   if (params_element != nullptr) {
     if (std::strncmp(params_element->Name(), "params", sizeof("params")) == 0) {
@@ -265,8 +268,6 @@ execute_command(std::string method_name, const tinyxml2::XMLElement* params_elem
       const auto* child = params_element->FirstChildElement("param");
 
       if (child != nullptr) {
-        std::function<void()> deleter = []() {};
-
         RpcManager::object_to_target(xml_value_to_object(child->FirstChildElement("value")), cmd_itr->second.m_flags, &target, &deleter);
         child = child->NextSiblingElement("param");
 
@@ -282,8 +283,6 @@ execute_command(std::string method_name, const tinyxml2::XMLElement* params_elem
       const auto* child = params_element->FirstChildElement("data")->FirstChildElement("value");
 
       if (child != nullptr) {
-        std::function<void()> deleter = []() {};
-
         RpcManager::object_to_target(xml_value_to_object(child), cmd_itr->second.m_flags, &target, &deleter);
         child = child->NextSiblingElement("value");
 
@@ -426,6 +425,14 @@ XmlRpc::process(const char* inBuffer, uint32_t length, slot_write slotWrite) {
     // remains.
     tinyxml2::XMLPrinter printer(nullptr, true, 0);
     process_document(&doc, &printer);
+
+    if (printer.CStrSize() - 1 > static_cast<int>(SCgiTask::max_response_size)) {
+      tinyxml2::XMLPrinter fault_printer(nullptr, true, 0);
+      print_xmlrpc_fault(XMLRPC_LIMIT_EXCEEDED_ERROR, "Response size exceeds maximum XML-RPC limit", &fault_printer);
+
+      return slotWrite(fault_printer.CStr(), fault_printer.CStrSize() - 1);
+    }
+
     return slotWrite(printer.CStr(), printer.CStrSize() - 1);
   } catch (rpc_error& e) {
     tinyxml2::XMLPrinter printer(nullptr, true, 0);

src/setup.cc

@@ -86,9 +86,13 @@ config_comment_log(const std::string& command, const std::string& raw_args) {
     pos = next_pos + 1;
   }
 
-  if (command == "log.add_output")
+  if (command == "log.add_output") {
+    if (args.size() != 2)
+      throw torrent::input_error("Invalid number of arguments.");
+
     log_add_group_output_str(args[0], args[1]);
-  else if (command == "log.open_file")
+
+  } else if (command == "log.open_file")
     apply_log_open_str(0, args);
   else if (command == "log.open_file.flush")
     apply_log_open_str(log_flag_flush, args);

src/ui/root.cc

@@ -467,6 +467,9 @@ Root::save_input_history() {
         history_file << entry << "|" + category.at((pitr->second + i) % m_input_history_length) + "\n";
   }
 
+  // The data only reaches the kernel here, so this is where a full disk is seen.
+  history_file.close();
+
   if (!history_file.good()) {
     lt_log_print(torrent::LOG_DEBUG, "input history file corrupted during writing, discarding (path:%s)", history_filename.c_str());
     return;
@@ -474,8 +477,6 @@ Root::save_input_history() {
     lt_log_print(torrent::LOG_DEBUG, "input history file written (path:%s)", history_filename.c_str());
   }
 
-  history_file.close();
-
   std::rename(history_filename_tmp.c_str(), history_filename.c_str());
 }
 

test/Makefile.am

@@ -1,4 +1,5 @@
 TESTS = \
+	rtorrent_Test_Core \
 	rtorrent_Test_Rpc \
 	rtorrent_Test_Src
 
@@ -7,6 +8,7 @@ check_PROGRAMS = $(TESTS)
 rtorrent_Test_LDADD = \
 	../src/libsub_root.a
 
+rtorrent_Test_Core_LDADD = $(rtorrent_Test_LDADD)
 rtorrent_Test_Rpc_LDADD = $(rtorrent_Test_LDADD)
 rtorrent_Test_Src_LDADD = $(rtorrent_Test_LDADD)
 
@@ -30,6 +32,10 @@ rtorrent_Test_Common = \
 	helpers/test_utils.h \
 	helpers/utils.h
 
+rtorrent_Test_Core_SOURCES = $(rtorrent_Test_Common) \
+	core/test_view.cc \
+	core/test_view.h
+
 rtorrent_Test_Rpc_SOURCES = $(rtorrent_Test_Common) \
 	rpc/test_command.cc \
 	rpc/test_command.h \
@@ -59,9 +65,13 @@ rtorrent_Test_Src_SOURCES = $(rtorrent_Test_Common) \
 	src/test_command_path.h \
 	src/test_command_string.cc \
 	src/test_command_string.h \
+	src/test_setup.cc \
+	src/test_setup.h \
 	src/test_watch_ready_queue.cc \
 	src/test_watch_ready_queue.h
 
+rtorrent_Test_Core_CXXFLAGS = $(CPPUNIT_CFLAGS)
+rtorrent_Test_Core_LDFLAGS = $(CPPUNIT_LIBS) -ldl
 rtorrent_Test_Rpc_CXXFLAGS = $(CPPUNIT_CFLAGS)
 rtorrent_Test_Rpc_LDFLAGS = $(CPPUNIT_LIBS) -ldl
 rtorrent_Test_Src_CXXFLAGS = $(CPPUNIT_CFLAGS)

test/core/test_view.cc

@@ -0,0 +1,158 @@
+#include "config.h"
+
+#include "test/core/test_view.h"
+
+#include <algorithm>
+#include <cstddef>
+#include <deque>
+#include <memory>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "command_helpers.h"
+#include "control.h"
+#include "core/download.h"
+#include "core/view.h"
+#include "globals.h"
+#include "rpc/parse_commands.h"
+
+CPPUNIT_TEST_SUITE_REGISTRATION(TestView);
+
+namespace {
+
+const char* filter_command  = "test.view.filter";
+const char* added_command   = "test.view.event_added";
+const char* removed_command = "test.view.event_removed";
+
+// View only stores these and hands them to the command layer as RPC targets,
+// which casts the pointer without reading through it.
+struct download_stub {
+  alignas(core::Download) std::byte storage[sizeof(core::Download)];
+};
+
+std::deque<download_stub>    stub_storage;
+std::vector<core::Download*> stub_downloads;
+
+std::set<core::Download*>    matches_filter;
+std::vector<core::Download*> added_events;
+std::vector<core::Download*> removed_events;
+
+std::shared_ptr<core::Download>
+make_stub_download() {
+  auto download = reinterpret_cast<core::Download*>(&stub_storage.emplace_back());
+
+  stub_downloads.push_back(download);
+
+  return std::shared_ptr<core::Download>(download, [](core::Download*) {});
+}
+
+// Renders a dispatch list as "d0,d2" so a failure names the downloads the
+// handler saw, not just how many there were.
+std::string
+describe(const std::vector<core::Download*>& downloads) {
+  std::string result;
+
+  for (const auto& download : downloads) {
+    auto itr = std::find(stub_downloads.begin(), stub_downloads.end(), download);
+
+    if (!result.empty())
+      result += ',';
+
+    result += 'd' + std::to_string(std::distance(stub_downloads.begin(), itr));
+  }
+
+  return result;
+}
+
+torrent::Object
+cmd_filter(core::Download* download, const torrent::Object&) {
+  return torrent::Object(static_cast<int64_t>(matches_filter.count(download)));
+}
+
+torrent::Object
+cmd_event_added(core::Download* download, const torrent::Object&) {
+  added_events.push_back(download);
+  return torrent::Object();
+}
+
+torrent::Object
+cmd_event_removed(core::Download* download, const torrent::Object&) {
+  removed_events.push_back(download);
+  return torrent::Object();
+}
+
+torrent::Object
+command_object(const char* command) {
+  return torrent::Object(std::string(command) + "=");
+}
+
+} // namespace
+
+void
+TestView::setUp() {
+  TestFixtureWithMainThread::setUp();
+
+  if (control == nullptr)
+    control = new Control;
+
+  if (!rpc::commands.has(filter_command)) {
+    CMD2_DL(filter_command, &cmd_filter);
+    CMD2_DL(added_command, &cmd_event_added);
+    CMD2_DL(removed_command, &cmd_event_removed);
+  }
+
+  stub_storage.clear();
+  stub_downloads.clear();
+  matches_filter.clear();
+  added_events.clear();
+  removed_events.clear();
+}
+
+void
+TestView::tearDown() {
+  TestFixtureWithMainThread::tearDown();
+}
+
+// d0 and d1 start visible and stop matching, d2 and d3 start filtered out and
+// start matching. The two halves are the same size on purpose: a test that
+// only counted the dispatches would pass even if both events were sent over
+// the same half of the changed range.
+void
+TestView::test_filter_dispatches_events_to_the_right_downloads() {
+  core::View view;
+  view.initialize("test_view");
+
+  auto d0 = make_stub_download();
+  auto d1 = make_stub_download();
+  auto d2 = make_stub_download();
+  auto d3 = make_stub_download();
+
+  view.insert(d0);
+  view.insert(d1);
+  view.insert(d2);
+  view.insert(d3);
+
+  view.set_visible(d0.get());
+  view.set_visible(d1.get());
+
+  CPPUNIT_ASSERT_EQUAL(core::View::size_type(2), view.size_visible());
+
+  matches_filter = {d2.get(), d3.get()};
+
+  view.set_filter(command_object(filter_command));
+  view.set_event_added(command_object(added_command));
+  view.set_event_removed(command_object(removed_command));
+
+  added_events.clear();
+  removed_events.clear();
+
+  view.filter();
+
+  CPPUNIT_ASSERT_EQUAL(std::string("d2,d3"), describe(added_events));
+  CPPUNIT_ASSERT_EQUAL(std::string("d0,d1"), describe(removed_events));
+
+  CPPUNIT_ASSERT_EQUAL(core::View::size_type(2), view.size_visible());
+  CPPUNIT_ASSERT(*view.begin_visible() == d2);
+  CPPUNIT_ASSERT(*(view.begin_visible() + 1) == d3);
+}

test/core/test_view.h

@@ -0,0 +1,15 @@
+#include "test/helpers/test_main_thread.h"
+
+class TestView : public TestFixtureWithMainThread {
+  CPPUNIT_TEST_SUITE(TestView);
+
+  CPPUNIT_TEST(test_filter_dispatches_events_to_the_right_downloads);
+
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+  void setUp();
+  void tearDown();
+
+  void test_filter_dispatches_events_to_the_right_downloads();
+};

test/rpc/test_jsonrpc.cc

@@ -8,12 +8,18 @@
 #include "globals.h"
 #include "command_helpers.h"
 #include "rpc/command_map.h"
+#include "rpc/scgi_task.h"
 
 CPPUNIT_TEST_SUITE_REGISTRATION(TestJsonrpc);
 
 torrent::Object
 jsonrpc_cmd_test_reflect([[maybe_unused]] rpc::target_type t, const torrent::Object& obj) { return obj; }
 
+torrent::Object
+jsonrpc_cmd_test_oversized([[maybe_unused]] rpc::target_type t, [[maybe_unused]] const torrent::Object& obj) {
+  return torrent::Object(std::string(rpc::SCgiTask::max_response_size + (1 << 20), 'a'));
+}
+
 void initialize_command_dynamic();
 
 // Name, Request, Expected response
@@ -130,6 +136,10 @@ TestJsonrpc::setUp() {
   if (rpc::commands.find("jsonrpc_reflect") == rpc::commands.end()) {
     CMD2_ANY("jsonrpc_reflect", &jsonrpc_cmd_test_reflect);
   }
+
+  if (rpc::commands.find("jsonrpc_oversized") == rpc::commands.end()) {
+    CMD2_ANY("jsonrpc_oversized", &jsonrpc_cmd_test_oversized);
+  }
 }
 
 void
@@ -145,3 +155,21 @@ TestJsonrpc::test_basics() {
     CPPUNIT_ASSERT_EQUAL_MESSAGE(std::get<0>(test), std::get<2>(test), output);
   }
 }
+
+// A command whose result does not fit in the SCGI response buffer must be
+// answered with a fault, not handed to the writer. SCgiTask::receive_write
+// treats an oversized body as an internal_error, which is not caught by any
+// RPC handler and terminates the process.
+void
+TestJsonrpc::test_response_size_limit() {
+  const std::string request = R"({"jsonrpc": "2.0", "method": "jsonrpc_oversized", "params": [""], "id": 1})";
+  const std::string expected = R"({"error":{"code":-32000,"message":"response size exceeds maximum RPC limit"},"id":1,"jsonrpc":"2.0"})";
+
+  std::string output;
+  m_jsonrpc.process(request.c_str(), request.size(), [&output](const char* c, uint32_t l) { output.append(c, l); return true; });
+
+  CPPUNIT_ASSERT_MESSAGE("response handed to the writer is " + std::to_string(output.size()) +
+                         " bytes, over the " + std::to_string(rpc::SCgiTask::max_response_size) + " byte SCGI limit",
+                         output.size() <= rpc::SCgiTask::max_response_size);
+  CPPUNIT_ASSERT_EQUAL(expected, output);
+}

test/rpc/test_jsonrpc.h

@@ -8,6 +8,7 @@ class TestJsonrpc : public test_fixture {
   CPPUNIT_TEST_SUITE(TestJsonrpc);
 
   CPPUNIT_TEST(test_basics);
+  CPPUNIT_TEST(test_response_size_limit);
 
   CPPUNIT_TEST_SUITE_END();
 
@@ -16,6 +17,7 @@ public:
   void tearDown();
 
   void test_basics();
+  void test_response_size_limit();
 
 private:
   std::unique_ptr<TestMainThread> m_test_main_thread;

test/rpc/test_object_storage.cc

@@ -49,6 +49,17 @@ TestObjectStorage::test_validate_keys() {
   torrent::raw_string raw_string_4("test_4\0foo", 10);
 
   ASSERT_CATCH_INPUT_ERROR( { m_storage.insert(raw_string_4, torrent::Object("a"), rpc::object_storage::flag_string_type); } );
+  ASSERT_CATCH_INPUT_ERROR( { m_storage.insert_str("", torrent::Object("a"), rpc::object_storage::flag_string_type); } );
+
+  std::string key_max(rpc::object_storage::key_size - 1, 'k');
+
+  CPPUNIT_ASSERT(m_storage.insert_str(key_max, torrent::Object("a"), rpc::object_storage::flag_string_type)->first == key_max);
+  ASSERT_CATCH_INPUT_ERROR( { m_storage.insert_str(key_max + 'k', torrent::Object("a"), rpc::object_storage::flag_string_type); } );
+
+  // The over-long key must not have been stored as the empty key.
+  CPPUNIT_ASSERT(m_storage.find_raw_string(torrent::raw_string::from_c_str("")) == m_storage.end());
+
+  m_storage.clear();
 }
 
 // And test many other bad/good string combos.

test/rpc/test_xmlrpc.cc

@@ -8,6 +8,7 @@
 #include "globals.h"
 #include "command_helpers.h"
 #include "rpc/command_map.h"
+#include "rpc/scgi_task.h"
 
 CPPUNIT_TEST_SUITE_REGISTRATION(TestXmlrpc);
 
@@ -21,6 +22,11 @@ xmlrpc_cmd_test_reflect_string([[maybe_unused]] rpc::target_type t, const std::s
   return obj;
 }
 
+torrent::Object
+xmlrpc_cmd_test_oversized([[maybe_unused]] rpc::target_type t, [[maybe_unused]] const torrent::Object& obj) {
+  return torrent::Object(std::string(rpc::SCgiTask::max_response_size + (1 << 20), 'a'));
+}
+
 void initialize_command_dynamic();
 
 #if defined(HAVE_XMLRPC_TINYXML2) && !defined(HAVE_XMLRPC_C)
@@ -127,6 +133,9 @@ TestXmlrpc::setUp() {
 
   if (rpc::commands.find("xmlrpc_reflect_string") == rpc::commands.end())
     CMD2_ANY_STRING("xmlrpc_reflect_string", &xmlrpc_cmd_test_reflect_string);
+
+  if (rpc::commands.find("xmlrpc_oversized") == rpc::commands.end())
+    CMD2_ANY("xmlrpc_oversized", &xmlrpc_cmd_test_oversized);
 }
 
 void
@@ -165,11 +174,30 @@ TestXmlrpc::test_size_limit() {
   CPPUNIT_ASSERT_EQUAL(expected, output);
 }
 
+// A command whose result does not fit in the SCGI response buffer must be
+// answered with a fault, not handed to the writer. SCgiTask::receive_write
+// treats an oversized body as an internal_error, which is not caught by any
+// RPC handler and terminates the process.
+void
+TestXmlrpc::test_response_size_limit() {
+  std::string input = "<?xml version=\"1.0\"?><methodCall><methodName>xmlrpc_oversized</methodName><params><param><value><string></string></value></param></params></methodCall>";
+  std::string expected = "<?xml version=\"1.0\"?><methodResponse><fault><value><struct><member><name>faultCode</name><value><i8>-509</i8></value></member><member><name>faultString</name><value><string>Response size exceeds maximum XML-RPC limit</string></value></member></struct></value></fault></methodResponse>";
+  std::string output;
+
+  m_xmlrpc.process(input.c_str(), input.size(), [&output](const char* c, uint32_t l){ output.append(c, l); return true;});
+
+  CPPUNIT_ASSERT_MESSAGE("response handed to the writer is " + std::to_string(output.size()) +
+                         " bytes, over the " + std::to_string(rpc::SCgiTask::max_response_size) + " byte SCGI limit",
+                         output.size() <= rpc::SCgiTask::max_response_size);
+  CPPUNIT_ASSERT_EQUAL(expected, output);
+}
+
 #else
 
 void TestXmlrpc::test_invalid_utf8() {}
 void TestXmlrpc::test_basics() {}
 void TestXmlrpc::test_size_limit() {}
+void TestXmlrpc::test_response_size_limit() {}
 void TestXmlrpc::setUp() {}
 void TestXmlrpc::tearDown() {}
 

test/rpc/test_xmlrpc.h

@@ -10,6 +10,7 @@ class TestXmlrpc : public test_fixture {
   CPPUNIT_TEST(test_basics);
   CPPUNIT_TEST(test_invalid_utf8);
   CPPUNIT_TEST(test_size_limit);
+  CPPUNIT_TEST(test_response_size_limit);
 
   CPPUNIT_TEST_SUITE_END();
 
@@ -22,6 +23,7 @@ public:
   void test_basics();
   void test_invalid_utf8();
   void test_size_limit();
+  void test_response_size_limit();
 
 private:
   std::unique_ptr<TestMainThread> m_test_main_thread;

test/src/test_command_dynamic.cc

@@ -61,3 +61,24 @@ TestCommandDynamic::test_old_style() {
   rpc::commands.call_command("method.insert", rpc::create_object_list("test_old_style.4", "simple", "cat=test.3"));
   CPPUNIT_ASSERT(rpc::commands.call_command("test_old_style.4", torrent::Object()).as_string() == "test.3");
 }
+
+void
+TestCommandDynamic::test_insert_list() {
+  torrent::Object key_only = torrent::Object::create_list();
+  key_only.as_list().push_back("test_insert_list.1");
+
+  rpc::commands.call_command("method.insert.list", key_only);
+
+  torrent::Object result = rpc::commands.call_command("test_insert_list.1", torrent::Object());
+
+  CPPUNIT_ASSERT(result.is_list());
+  CPPUNIT_ASSERT(result.as_list().empty());
+
+  rpc::commands.call_command("method.insert.list",
+                             rpc::create_object_list("test_insert_list.2", rpc::create_object_list("a", "b")));
+
+  torrent::Object filled = rpc::commands.call_command("test_insert_list.2", torrent::Object());
+
+  CPPUNIT_ASSERT(filled.is_list());
+  CPPUNIT_ASSERT_EQUAL((size_t)2, filled.as_list().size());
+}

test/src/test_command_dynamic.h

@@ -7,6 +7,7 @@ class TestCommandDynamic : public test_fixture {
   CPPUNIT_TEST(test_basics);
   CPPUNIT_TEST(test_get_set);
   CPPUNIT_TEST(test_old_style);
+  CPPUNIT_TEST(test_insert_list);
 
   CPPUNIT_TEST_SUITE_END();
 
@@ -18,6 +19,7 @@ public:
   void test_get_set();
 
   void test_old_style();
+  void test_insert_list();
 
 private:
   std::unique_ptr<TestMainThread> m_test_main_thread;

test/src/test_setup.cc

@@ -0,0 +1,78 @@
+#include "config.h"
+
+#include "test/src/test_setup.h"
+
+#include <fstream>
+#include <string>
+#include <unistd.h>
+#include <torrent/exceptions.h>
+
+#include "setup.h"
+
+CPPUNIT_TEST_SUITE_REGISTRATION(TestSetup);
+
+// Linking setup.o pulls in the help printer, which lives in src/main.cc.
+void
+print_help() {}
+
+namespace {
+
+class temp_config_file {
+public:
+  temp_config_file(const std::string& contents) {
+    char path[] = "/tmp/rtorrent_test_setup_XXXXXX";
+
+    CPPUNIT_ASSERT(::mkstemp(path) != -1);
+    m_path = path;
+
+    std::ofstream file(m_path);
+    file << contents << '\n';
+  }
+
+  ~temp_config_file() { ::unlink(m_path.c_str()); }
+
+  const std::string& path() const { return m_path; }
+
+private:
+  std::string m_path;
+};
+
+// The group name must be a valid one, else option_find_string throws before
+// the output argument is ever touched.
+void
+assert_arg_count_error(const std::string& line) {
+  temp_config_file file(line);
+
+  try {
+    parse_config_file_comments(file.path());
+  } catch (torrent::input_error& e) {
+    CPPUNIT_ASSERT_EQUAL(std::string("Invalid number of arguments."), std::string(e.what()));
+    return;
+  }
+
+  CPPUNIT_FAIL("no torrent::input_error thrown for: " + line);
+}
+
+} // namespace
+
+void
+TestSetup::test_config_comment_log_add_output() {
+  temp_config_file file("# do:log.add_output=debug,test_output");
+
+  CPPUNIT_ASSERT_NO_THROW(parse_config_file_comments(file.path()));
+}
+
+void
+TestSetup::test_config_comment_log_add_output_no_args() {
+  assert_arg_count_error("# do:log.add_output=");
+}
+
+void
+TestSetup::test_config_comment_log_add_output_one_arg() {
+  assert_arg_count_error("# do:log.add_output=debug");
+}
+
+void
+TestSetup::test_config_comment_log_add_output_too_many_args() {
+  assert_arg_count_error("# do:log.add_output=debug,test_output,extra");
+}

test/src/test_setup.h

@@ -0,0 +1,18 @@
+#include "test/helpers/test_fixture.h"
+
+class TestSetup : public test_fixture {
+  CPPUNIT_TEST_SUITE(TestSetup);
+
+  CPPUNIT_TEST(test_config_comment_log_add_output);
+  CPPUNIT_TEST(test_config_comment_log_add_output_no_args);
+  CPPUNIT_TEST(test_config_comment_log_add_output_one_arg);
+  CPPUNIT_TEST(test_config_comment_log_add_output_too_many_args);
+
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+  void test_config_comment_log_add_output();
+  void test_config_comment_log_add_output_no_args();
+  void test_config_comment_log_add_output_one_arg();
+  void test_config_comment_log_add_output_too_many_args();
+};