Emulation: Fix boot path resolving

* Fix /dev_flash executables path arg. (/host_root is wrong for it)
* Fix usage of /host_root for homebrew applications when it is not mounted, use /app_home.
* Fix path source detection. (don't get fooled by path slashes repetitions and '\' on Windows)
* Fix fs::escape_path for comparisons. (inserted NTS character at the end due to a bug, always not include delimiter at the end)

Utilities/File.cpp

@@ -1801,9 +1801,9 @@ std::string fs::escape_path(std::string_view path)
 		}
 	}
 
-	if (j != umax && (real[j] == delim[0] || real[j] == delim[1])) j--; // Do not include a delmiter at the end
+	if (j >= 1u && (real[j - 1] == delim[0] || real[j - 1] == delim[1])) j--; // Do not include a delmiter at the end
 
-	real.resize(j + 1);
+	real.resize(j);
 	return real;
 }
 

rpcs3/Emu/System.cpp

@@ -1266,15 +1266,23 @@ game_boot_result Emulator::Load(const std::string& title_id, bool add_only, bool
 			return game_boot_result::no_errors;
 		}
 
+		// Check if path is inside the specified directory 
+		auto is_path_inside_path = [](std::string_view path, std::string_view dir)
+		{
+			return (fs::escape_path(path) + '/').starts_with(fs::escape_path(dir) + '/');
+		};
+
 		// Detect boot location
 		constexpr usz game_dir_size = 8; // size of PS3_GAME and PS3_GMXX
 		const std::string hdd0_game = vfs::get("/dev_hdd0/game/");
 		const std::string hdd0_disc = vfs::get("/dev_hdd0/disc/");
-		const bool from_hdd0_game   = m_path.starts_with(hdd0_game);
+		const bool from_hdd0_game   = is_path_inside_path(m_path, hdd0_game);
+		const bool from_dev_flash   = is_path_inside_path(m_path, g_cfg.vfs.get_dev_flash());
 
 #ifdef _WIN32
 		// m_path might be passed from command line with differences in uppercase/lowercase on windows.
-		if (!from_hdd0_game && fmt::to_lower(m_path).starts_with(fmt::to_lower(hdd0_game)))
+		if ((!from_hdd0_game && is_path_inside_path(fmt::to_lower(m_path), fmt::to_lower(hdd0_game))) ||
+			(!from_dev_flash && is_path_inside_path(fmt::to_lower(m_path), fmt::to_lower(g_cfg.vfs.get_dev_flash()))))
 		{
 			// Let's just abort to prevent errors down the line.
 			sys_log.error("The boot path seems to contain incorrectly cased characters. Please adjust the path and try again.");
@@ -1313,7 +1321,7 @@ game_boot_result Emulator::Load(const std::string& title_id, bool add_only, bool
 					bdvd_dir = sfb_dir + "/";
 
 					// Find game dir
-					if (const std::string main_dir_name = main_dir.substr(main_dir.find_last_of("/\\") + 1);
+					if (const std::string main_dir_name = main_dir.substr(main_dir.find_last_of(fs::delim) + 1);
 						main_dir_name.size() == game_dir_size)
 					{
 						m_game_dir = main_dir_name;
@@ -1638,31 +1646,54 @@ game_boot_result Emulator::Load(const std::string& title_id, bool add_only, bool
 
 			if (argv[0].empty())
 			{
+				auto unescape = [](std::string_view path)
+				{
+					// Unescape from host FS
+					std::vector<std::string> escaped = fmt::split(path, {std::string_view{&fs::delim[0], 1}, std::string_view{&fs::delim[1], 1}});
+					std::vector<std::string> result;
+					for (auto& sv : escaped)
+						result.emplace_back(vfs::unescape(sv));
+
+					return fmt::merge(result, "/");
+				};
+
 				if (from_hdd0_game && m_cat == "DG")
 				{
-					argv[0] = "/dev_bdvd/PS3_GAME/" + m_path.substr(hdd0_game.size() + 10);
+					argv[0] = "/dev_bdvd/PS3_GAME/" + unescape(m_path.substr(hdd0_game.size() + 10));
 					m_dir = "/dev_hdd0/game/" + m_path.substr(hdd0_game.size(), 10);
 					sys_log.notice("Disc path: %s", m_dir);
 				}
 				else if (from_hdd0_game)
 				{
-					argv[0] = "/dev_hdd0/game/" + m_path.substr(hdd0_game.size());
+					argv[0] = "/dev_hdd0/game/" + unescape(m_path.substr(hdd0_game.size()));
 					m_dir = "/dev_hdd0/game/" + m_path.substr(hdd0_game.size(), 10);
 					sys_log.notice("Boot path: %s", m_dir);
 				}
 				else if (!bdvd_dir.empty() && fs::is_dir(bdvd_dir))
 				{
 					// Disc games are on /dev_bdvd/
 					const usz pos = m_path.rfind(m_game_dir);
-					argv[0] = "/dev_bdvd/PS3_GAME/" + m_path.substr(pos + game_dir_size + 1);
+					argv[0] = "/dev_bdvd/PS3_GAME/" + unescape(m_path.substr(pos + game_dir_size + 1));
 					m_dir = "/dev_bdvd/PS3_GAME/";
 				}
-				else
+				else if (from_dev_flash)
+				{
+					// Firmware executables
+					argv[0] = "/dev_flash" + fs::escape_path(m_path).substr(fs::escape_path(g_cfg.vfs.get_dev_flash()).size());
+					m_dir = fs::get_parent_dir(argv[0]) + '/';
+				}
+				else if (g_cfg.vfs.host_root)
 				{
 					// For homebrew
 					argv[0] = "/host_root/" + m_path;
 					m_dir = "/host_root/" + elf_dir + '/';
 				}
+				else
+				{
+					// Use /app_home if /host_root is disabled
+					argv[0] = "/app_home/" + m_path.substr(m_path.find_last_of(fs::delim) + 1);
+					m_dir = "/app_home/";
+				}
 
 				sys_log.notice("Elf path: %s", argv[0]);
 			}

rpcs3/Emu/VFS.cpp

@@ -1,4 +1,4 @@
-#include "stdafx.h"
+#include "stdafx.h"
 #include "IdManager.h"
 #include "System.h"
 #include "VFS.h"