FreeRDP/libfreerdp-utils/load_plugin.c

279 lines
7.1 KiB
C

/**
* FreeRDP: A Remote Desktop Protocol Client
* Plugin Loading Utils
*
* Copyright 2011 Vic Lee
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <winpr/windows.h>
#include <freerdp/utils/file.h>
#include <freerdp/utils/print.h>
#include <freerdp/utils/memory.h>
#include <freerdp/utils/load_plugin.h>
#ifdef _WIN32
#define DLOPEN(f) LoadLibraryA(f)
#define DLSYM(f, n) GetProcAddress(f, n)
#define DLCLOSE(f) FreeLibrary(f)
#define DLERROR() ""
#else
#include <dlfcn.h>
#include <unistd.h>
#define DLOPEN(f) dlopen(f, RTLD_LOCAL | RTLD_LAZY)
#define DLSYM(f, n) dlsym(f, n)
#define DLCLOSE(f) dlclose(f)
#define DLERROR() dlerror()
#endif
/**
* UNUSED
* This function opens a handle on the specified library in order to load symbols from it.
* It is just a wrapper over dlopen(), but provides some logs in case of error.
*
* The returned pointer can be used to load a symbol from the library, using the freerdp_get_library_symbol() call.
* The returned pointer should be closed using the freerdp_close_library() call.
*
* @see freerdp_get_library_symbol
* @see freerdp_close_library
*
* @param file [IN] - library name
* @return Pointer to the loaded library. NULL if an error occurs.
*/
void* freerdp_open_library(const char* file)
{
void* library;
library = DLOPEN(file);
if (library == NULL)
{
printf("freerdp_load_library: failed to open %s: %s\n", file, DLERROR());
return NULL;
}
return library;
}
/**
* UNUSED
* This function retrieves a pointer to the specified symbol from the given (loaded) library.
* It is a wrapper over the dlsym() function, but provides some logs in case of error.
*
* @see freerdp_open_library
* @see freerdp_close_library
*
* @param library [IN] - a valid pointer to the opened library.
* This pointer should come from a successful call to freerdp_open_library()
* @param name [IN] - name of the symbol that must be loaded
*
* @return A pointer to the loaded symbol. NULL if an error occured.
*/
void* freerdp_get_library_symbol(void* library, const char* name)
{
void* symbol;
symbol = DLSYM(library, name);
if (symbol == NULL)
{
printf("freerdp_get_library_symbol: failed to load %s: %s\n", name, DLERROR());
return NULL;
}
return symbol;
}
/**
* UNUSED
* This function closes a library handle that was previously opened by freerdp_open_library().
* It is a wrapper over dlclose(), but provides logs in case of error.
*
* @see freerdp_open_library
* @see freerdp_get_library_symbol
*
* @return true if the close succeeded. false otherwise.
*/
boolean freerdp_close_library(void* library)
{
int status;
status = DLCLOSE(library);
#ifdef _WIN32
if (status != 0)
#else
if (status == 0)
#endif
{
printf("freerdp_free_library: failed to close: %s\n", DLERROR());
return false;
}
return true;
}
/**
* This function will load the specified library, retrieve the specified symbol in it, and return a pointer to it.
* It is used in freerdp_load_plugin() and freerdp_load_channel_plugin().
* It seems there is no way to unload the library once this call is made. Now since this is used for plugins,
* we probably don't need to take care of unloading them, as it will be done only at shutdown.
*
* @param file [IN] - library name
* @param name [IN] - symbol name to find in the library
*
* @return pointer to the referenced symbol. NULL if an error occured.
*/
void* freerdp_load_library_symbol(const char* file, const char* name)
{
void* library;
void* symbol;
library = DLOPEN(file);
if (library == NULL)
{
printf("freerdp_load_library_symbol: failed to open %s: %s\n", file, DLERROR());
return NULL;
}
symbol = DLSYM(library, name);
if (symbol == NULL)
{
printf("freerdp_load_library_symbol: failed to load %s: %s\n", file, DLERROR());
return NULL;
}
return symbol;
}
/**
* This function is used to load plugins. It will load the specified library, retrieve the specified symbol,
* and return a pointer to it.
* There is no way to unload the library once it has been loaded this way - since it is used for plugins only,
* maybe it's not a must.
*
* @param name [IN] - name of the library to load
* @param entry_name [IN] - name of the symbol to find and load from the library
*
* @return Pointer to the loaded symbol. NULL if an error occurred.
*/
void* freerdp_load_plugin(const char* name, const char* entry_name)
{
char* path;
void* entry;
char* suffixed_name;
suffixed_name = freerdp_append_shared_library_suffix((char*) name);
if (!freerdp_path_contains_separator(suffixed_name))
{
/* no explicit path given, use default path */
path = freerdp_construct_path(FREERDP_PLUGIN_PATH, suffixed_name);
}
else
{
/* explicit path given, use it instead of default path */
path = xstrdup(suffixed_name);
}
entry = freerdp_load_library_symbol(path, entry_name);
xfree(suffixed_name);
xfree(path);
if (entry == NULL)
{
printf("freerdp_load_plugin: failed to load %s/%s\n", name, entry_name);
return NULL;
}
return entry;
}
/**
* UNUSED
* This function was meant to be used to load channel plugins.
* It was initially called from freerdp_channels_load_plugin() but now we use the freerdp_load_plugin() function
* which is more generic.
*
*/
void* freerdp_load_channel_plugin(rdpSettings* settings, const char* name, const char* entry_name)
{
char* path;
void* entry;
char* suffixed_name;
suffixed_name = freerdp_append_shared_library_suffix((char*) name);
if (!freerdp_path_contains_separator(suffixed_name))
{
/* no explicit path given, use default path */
if (!settings->development_mode)
{
path = freerdp_construct_path(FREERDP_PLUGIN_PATH, suffixed_name);
}
else
{
char* dot;
char* plugin_name;
char* channels_path;
char* channel_subpath;
dot = strrchr(suffixed_name, '.');
plugin_name = xmalloc((dot - suffixed_name) + 1);
strncpy(plugin_name, suffixed_name, (dot - suffixed_name));
plugin_name[(dot - suffixed_name)] = '\0';
channels_path = freerdp_construct_path(settings->development_path, "channels");
channel_subpath = freerdp_construct_path(channels_path, plugin_name);
path = freerdp_construct_path(channel_subpath, suffixed_name);
xfree(plugin_name);
xfree(channels_path);
xfree(channel_subpath);
}
}
else
{
/* explicit path given, use it instead of default path */
path = xstrdup(suffixed_name);
}
entry = freerdp_load_library_symbol(path, entry_name);
xfree(suffixed_name);
xfree(path);
if (entry == NULL)
{
printf("freerdp_load_channel_plugin: failed to load %s/%s\n", name, entry_name);
return NULL;
}
return entry;
}