fix(plugin): Use UTF-8 paths on Windows

Document that plugin paths should be UTF-8 on Windows, and convert them
to UTF-16 internally.

In sinsp-example, add an application manifest that sets activeCodePage
to UTF-8 on Windows.

Signed-off-by: Gerald Combs <[email protected]>

Author: geraldcombs

userspace/libsinsp/examples/CMakeLists.txt

@@ -19,7 +19,9 @@ include(jsoncpp)
 set(sources util.cpp test.cpp)
 
 if(CMAKE_SYSTEM_NAME MATCHES "Linux")
-	set(sources ${sources} perftest.cpp)
+	list(APPEND sources perftest.cpp)
+elseif(CMAKE_SYSTEM_NAME MATCHES "Windows")
+	list(APPEND sources sinsp-example.manifest)
 endif()
 
 add_executable(sinsp-example ${sources})

userspace/libsinsp/examples/sinsp-example.manifest

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
+  <assemblyIdentity type="win32" name="FalcoSecurity.SinspExample" version="6.0.0.0"/>
+  <application>
+    <windowsSettings>
+      <activeCodePage xmlns="http://schemas.microsoft.com/SMI/2019/WindowsSettings">UTF-8</activeCodePage>
+    </windowsSettings>
+  </application>
+</assembly>

userspace/libsinsp/sinsp.h

@@ -734,6 +734,8 @@ class SINSP_PUBLIC sinsp : public capture_stats_source {
 	// Create and register a plugin from a shared library pointed
 	// to by filepath, and add it to the inspector.
 	// The created sinsp_plugin is returned.
+	// filepath must be encoded as UTF-8 on Windows.
+
 	std::shared_ptr<sinsp_plugin> register_plugin(const std::string& filepath);
 
 	// Create and register a plugin given a custom API vtable.

userspace/plugin/plugin_loader.c

@@ -71,7 +71,24 @@ plugin_handle_t* plugin_load(const char* path, char* err) {
 
 	// open dynamic library
 #ifdef _WIN32
-	ret->handle = LoadLibrary(path);
+	// Using LoadLibraryW ensures that we have a valid path independent
+	// of the system or application code page.
+	int wpath_len = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, path, -1, NULL, 0);
+	if(wpath_len <= 0) {
+		free(ret);
+		strlcpy(err, "unable to decode plugin path", PLUGIN_MAX_ERRLEN);
+		return NULL;
+	}
+
+	WCHAR* wpath = malloc(wpath_len * sizeof(WCHAR));
+	if(MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, path, -1, wpath, wpath_len) <= 0) {
+		free(ret);
+		free(wpath);
+		strlcpy(err, "unable to decode plugin path", PLUGIN_MAX_ERRLEN);
+		return NULL;
+	}
+	ret->handle = LoadLibraryW(wpath);
+	free(wpath);
 	if(ret->handle == NULL) {
 		DWORD flg = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
 		            FORMAT_MESSAGE_IGNORE_INSERTS;

userspace/plugin/plugin_loader.h

@@ -72,6 +72,8 @@ plugin_handle_t* plugin_load_api(const plugin_api* api, char* err);
     \brief Loads a dynamic library from the given path and returns a
     plugin_handle_t* representing the loaded plugin. In case of error,
     returns NULL and fills the err string up to PLUGIN_MAX_ERRLEN chars.
+
+    The path must be encoded as UTF-8 on Windows.
 */
 plugin_handle_t* plugin_load(const char* path, char* err);