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#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <dlfcn.h>
#include "websocksy.h"
#include "plugin.h"
//cheap out because i dont want the overhead of allocating here
#define MAX_PLUGIN_PATH 4096
static size_t framing_functions = 0;
static ws_framing* framing_function = NULL;
static char** framing_function_name = NULL;
static size_t attached_libraries = 0;
static void** attached_library = NULL;
/* Attach a shared object and register it to be unloaded at shutdown */
static void* plugin_attach(char* path){
void* module = dlopen(path, RTLD_NOW);
if(!module){
fprintf(stderr, "Failed to load module %s\n", dlerror());
return NULL;
}
attached_library = realloc(attached_library, (attached_libraries + 1) * sizeof(void*));
if(!attached_library){
fprintf(stderr, "Failed to allocate memory\n");
dlclose(module);
return NULL;
}
attached_library[attached_libraries] = module;
attached_libraries++;
return module;
}
/*
* Try to load all framing plugins by attaching all shared objects in the
* plugin path that
* * are not backend plugins
* * have a filename ending in .so
*/
int plugin_framing_load(char* path){
DIR* directory = opendir(path);
struct dirent* file = NULL;
char plugin_path[MAX_PLUGIN_PATH] = "";
if(strlen(path) >= sizeof(plugin_path) - 20 || strlen(path) == 0){
fprintf(stderr, "Plugin path length exceeds limit\n");
return 1;
}
if(!directory){
fprintf(stderr, "Failed to open directory %s: %s\n", path, strerror(errno));
return 0;
}
for(file = readdir(directory); file; file = readdir(directory)){
//skip backends
if(!strncmp(file->d_name, "backend_", 8)){
continue;
}
//skip file not ending in .so
if(strlen(file->d_name) < 4 || strcmp(file->d_name + strlen(file->d_name) - 3, ".so")){
continue;
}
snprintf(plugin_path, sizeof(plugin_path), "%s%s%s", path, (path[strlen(path) - 1] == '/') ? "" : "/", file->d_name);
if(!plugin_attach(plugin_path)){
return 1;
}
}
closedir(directory);
return 0;
}
/*
* Load an external backend plugin by constructing it's module path and attaching it,
* then try to resolve the required backend symbols
*/
int plugin_backend_load(char* path, char* backend_requested, ws_backend* backend){
char plugin_path[MAX_PLUGIN_PATH] = "";
void* handle = NULL;
if(strlen(path) >= sizeof(plugin_path) - 30 || strlen(path) == 0){
fprintf(stderr, "Plugin path length exceeds limit\n");
return 1;
}
snprintf(plugin_path, sizeof(plugin_path), "%s%sbackend_%s.so", path, (path[strlen(path) - 1] == '/') ? "" : "/", backend_requested);
handle = plugin_attach(plugin_path);
if(!handle){
return 1;
}
//read backend functions into the structure
backend->init = (ws_backend_init) dlsym(handle, "init");
backend->config = (ws_backend_configure) dlsym(handle, "configure");
backend->query = (ws_backend_query) dlsym(handle, "query");
backend->cleanup = (ws_backend_cleanup) dlsym(handle, "cleanup");
if(!backend->init || !backend->query){
fprintf(stderr, "Backend module %s is missing required symbols\n", plugin_path);
return 1;
}
return 0;
}
/* Register a new framing function to the library */
int plugin_register_framing(char* name, ws_framing func){
size_t u;
for(u = 0; u < framing_functions; u++){
if(!strcmp(framing_function_name[u], name)){
fprintf(stderr, "Replacing framing %s\n", name);
break;
}
}
if(u == framing_functions){
framing_function = realloc(framing_function, (framing_functions + 1) * sizeof(ws_framing));
framing_function_name = realloc(framing_function_name, (framing_functions + 1) * sizeof(char*));
if(!framing_function || !framing_function_name){
fprintf(stderr, "Failed to allocate memory for framing function\n");
return 1;
}
framing_function_name[u] = strdup(name);
framing_functions++;
}
framing_function[u] = func;
return 0;
}
/* Query the framing function library */
ws_framing plugin_framing(char* name){
size_t u;
if(!name){
return plugin_framing("auto");
}
for(u = 0; u < framing_functions; u++){
if(!strcmp(framing_function_name[u], name)){
return framing_function[u];
}
}
//if unknown framing, return the default
return plugin_framing("auto");
}
/* Release all allocated memory, detach all loaded shared objects */
void plugin_cleanup(){
size_t u;
//free allocated buffers
for(u = 0; u < framing_functions; u++){
free(framing_function_name[u]);
}
free(framing_function);
framing_function = NULL;
free(framing_function_name);
framing_function_name = 0;
framing_function = NULL;
framing_functions = 0;
//dlclose all plugins
for(u = 0; u < attached_libraries; u++){
dlclose(attached_library[u]);
}
free(attached_library);
attached_libraries = 0;
}
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