lsteamclient: Introduce unix-side buffer cache with PE allocate pointers.

There are several steam API calls that currently pass unix pointers
for e.g. strings directly to the PE-side, this allows for caching such
return values and returning a PE-side pointer instead.

lsteamclient/gen_wrapper.py

@@ -211,6 +211,7 @@ UNIX_FUNCS = [
     'steamclient_init',
     'steamclient_init_registry',
     'steamclient_next_callback',
+    'steamclient_get_unix_buffer',
     'steamclient_CreateInterface',
     'steamclient_Steam_GetAPICallResult',
     'steamclient_Steam_BGetCallback',

lsteamclient/steamclient_main.c

@@ -325,6 +325,24 @@ done:
     return ret;
 }
 
+void *get_unix_buffer( struct u_buffer buf )
+{
+    struct steamclient_get_unix_buffer_params params = {.buf = buf};
+    void *ret;
+
+    if ((UINT_PTR)buf.ptr == buf.ptr && (UINT_PTR)(buf.ptr + buf.len) == (buf.ptr + buf.len))
+        return (void *)(UINT_PTR)buf.ptr;
+
+    if (!(params.ptr = ret = HeapAlloc( GetProcessHeap(), 0, buf.len ))) return NULL;
+    if (STEAMCLIENT_CALL( steamclient_get_unix_buffer, &params ) || (ret != params.ptr))
+    {
+        HeapFree( GetProcessHeap(), 0, ret );
+        ret = params.ptr;
+    }
+
+    return ret;
+}
+
 static BOOL get_env_win(const WCHAR *name, char *value, unsigned int size)
 {
     DWORD i, env_size;

lsteamclient/steamclient_private.h

@@ -46,6 +46,7 @@ extern void execute_pending_callbacks(void);
 struct w_iface *create_win_interface( const char *name, struct u_iface );
 void *alloc_mem_for_iface(size_t size, const char *iface_version);
 void *alloc_vtable(void *vtable, unsigned int method_count, const char *iface_version);
+void *get_unix_buffer( struct u_buffer buf );
 
 void init_rtti( char *base );
 

lsteamclient/steamclient_structs.h

@@ -67,4 +67,14 @@ struct u_iface
 #endif /* __cplusplus */
 };
 
+struct u_buffer
+{
+    UINT64 ptr;
+    UINT64 len;
+#ifdef __cplusplus
+    struct u_buffer &operator=(const char* value) { this->ptr = (UINT_PTR)value; this->len = value ? strlen( value ) + 1 : 0; return *this; }
+    operator char*() const { return (char*)(UINT_PTR)this->ptr; }
+#endif /* __cplusplus */
+};
+
 #endif /* __STEAMCLIENT_STRUCTS_H */

lsteamclient/unix_private.h

@@ -74,6 +74,7 @@ void convert_callback_utow( int id, void *u_callback, int u_callback_len, void *
 extern NTSTATUS steamclient_init( void * );
 extern NTSTATUS steamclient_init_registry( void * );
 extern NTSTATUS steamclient_next_callback( void * );
+extern NTSTATUS steamclient_get_unix_buffer( void * );
 extern NTSTATUS steamclient_CreateInterface( void * );
 extern NTSTATUS steamclient_Steam_GetAPICallResult( void * );
 extern NTSTATUS steamclient_Steam_BGetCallback( void * );

lsteamclient/unixlib.cpp

@@ -6,6 +6,7 @@
 #include <pthread.h>
 #include <stdlib.h>
 #include <dlfcn.h>
+#include <unordered_map>
 
 #if 0
 #pragma makedep unix
@@ -683,6 +684,38 @@ NTSTATUS steamclient_init( void *args )
     return 0;
 }
 
+namespace std
+{
+template<> struct hash< struct u_buffer >
+{
+    using argument_type = struct u_buffer;
+    using result_type = std::size_t;
+    result_type operator()( argument_type const& buf ) const { return buf.ptr; }
+};
+}
+
+static pthread_mutex_t buffer_cache_lock = PTHREAD_MUTEX_INITIALIZER;
+static std::unordered_map< struct u_buffer, void * > buffer_cache;
+
+NTSTATUS steamclient_get_unix_buffer( void *args )
+{
+    struct steamclient_get_unix_buffer_params *params = (struct steamclient_get_unix_buffer_params *)args;
+    struct cache_entry *entry;
+    struct rb_entry *ptr;
+
+    pthread_mutex_lock( &buffer_cache_lock );
+    auto iter = buffer_cache.find( params->buf );
+    if (iter != buffer_cache.end()) params->ptr = iter->second;
+    else
+    {
+        memcpy( params->ptr, (char *)params->buf, params->buf.len );
+        buffer_cache[params->buf] = params->ptr;
+    }
+    pthread_mutex_unlock( &buffer_cache_lock );
+
+    return 0;
+}
+
 NTSTATUS steamclient_CreateInterface( void *args )
 {
     struct steamclient_CreateInterface_params *params = (struct steamclient_CreateInterface_params *)args;

lsteamclient/unixlib.h

@@ -32,6 +32,12 @@ struct steamclient_init_params
     int8_t ignore_child_processes_unset;
 };
 
+struct steamclient_get_unix_buffer_params
+{
+    struct u_buffer buf;
+    void *ptr; /* client-side ptr */
+};
+
 enum callback_type
 {
     SOCKETS_DEBUG_OUTPUT = 1,

lsteamclient/unixlib_generated.cpp

@@ -11,6 +11,7 @@ extern "C" const unixlib_entry_t __wine_unix_call_funcs[] =
     steamclient_init,
     steamclient_init_registry,
     steamclient_next_callback,
+    steamclient_get_unix_buffer,
     steamclient_CreateInterface,
     steamclient_Steam_GetAPICallResult,
     steamclient_Steam_BGetCallback,

lsteamclient/unixlib_generated.h

@@ -48759,6 +48759,7 @@ enum unix_funcs
     unix_steamclient_init,
     unix_steamclient_init_registry,
     unix_steamclient_next_callback,
+    unix_steamclient_get_unix_buffer,
     unix_steamclient_CreateInterface,
     unix_steamclient_Steam_GetAPICallResult,
     unix_steamclient_Steam_BGetCallback,