From 921ce069a4770fbadad7bb4e806361e857469409 Mon Sep 17 00:00:00 2001
From: cbdev <cb@cbcdn.com>
Date: Mon, 21 Jun 2021 22:03:17 +0200
Subject: Repository cleanup

---
 core/plugin.c | 187 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 187 insertions(+)
 create mode 100644 core/plugin.c

(limited to 'core/plugin.c')

diff --git a/core/plugin.c b/core/plugin.c
new file mode 100644
index 0000000..e7d8eba
--- /dev/null
+++ b/core/plugin.c
@@ -0,0 +1,187 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include "portability.h"
+#ifdef _WIN32
+#define dlclose FreeLibrary
+#define dlsym GetProcAddress
+#define dlerror() "Failed"
+#define dlopen(lib,ig) LoadLibrary(lib)
+#else
+#include <dlfcn.h>
+#endif
+
+#include "plugin.h"
+
+static size_t plugins = 0;
+static void** plugin_handle = NULL;
+
+static int plugin_attach(char* path, char* file){
+	plugin_init init = NULL;
+	void* handle = NULL;
+	char* lib = NULL;
+	#ifdef _WIN32
+	char* path_separator = "\\";
+	#else
+	char* path_separator = "/";
+	#endif
+
+	if(!path || !file || !strlen(path)){
+		fprintf(stderr, "Invalid plugin loader path\n");
+		return 1;
+	}
+
+	lib = calloc(strlen(path) + strlen(file) + 2, sizeof(char));
+	if(!lib){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return 1;
+	}
+	snprintf(lib, strlen(path) + strlen(file) + 2, "%s%s%s",
+			path,
+			(path[strlen(path) - 1] == path_separator[0]) ? "" : path_separator,
+			file);
+
+	handle = dlopen(lib, RTLD_NOW);
+	if(!handle){
+		#ifdef _WIN32
+		char* error = NULL;
+		FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+			NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &error, 0, NULL);
+		fprintf(stderr, "Failed to load plugin %s, check that all supporting libraries are present: %s\n", lib, error);
+		LocalFree(error);
+		#else
+		fprintf(stderr, "Failed to load plugin %s: %s\n", lib, dlerror());
+		#endif
+		free(lib);
+		return 0;
+	}
+
+	init = (plugin_init) dlsym(handle, "init");
+	if(init){
+		if(init()){
+			fprintf(stderr, "Plugin %s failed to initialize\n", lib);
+			dlclose(handle);
+			free(lib);
+			return 1;
+		}
+	}
+	else{
+		dlclose(handle);
+		free(lib);
+		return 0;
+	}
+	free(lib);
+
+	plugin_handle = realloc(plugin_handle, (plugins + 1) * sizeof(void*));
+	if(!plugin_handle){
+		fprintf(stderr, "Failed to allocate memory\n");
+		dlclose(handle);
+		return 1;
+	}
+
+	plugin_handle[plugins] = handle;
+	plugins++;
+
+	return 0;
+}
+
+int plugins_load(char* path){
+	int rv = -1;
+
+#ifdef _WIN32
+	char* search_expression = calloc(strlen(path) + strlen("*.dll") + 1, sizeof(char));
+	if(!search_expression){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return -1;
+	}
+	snprintf(search_expression, strlen(path) + strlen("*.dll"), "%s*.dll", path);
+
+	WIN32_FIND_DATA result;
+	HANDLE hSearch = FindFirstFile(search_expression, &result);
+
+	if(hSearch == INVALID_HANDLE_VALUE){
+		LPVOID lpMsgBuf = NULL;
+		FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+			NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &lpMsgBuf, 0, NULL);
+		fprintf(stderr, "Failed to search for backend plugin files in %s: %s\n", path, lpMsgBuf);
+		LocalFree(lpMsgBuf);
+		return -1;
+	}
+
+	do {
+		if(plugin_attach(path, result.cFileName)){
+			goto load_done;
+		}
+	} while(FindNextFile(hSearch, &result));
+
+	rv = 0;
+load_done:
+	free(search_expression);
+	FindClose(hSearch);
+	return rv;
+#else
+	struct dirent* entry;
+	struct stat file_stat;
+	DIR* directory = opendir(path);
+	if(!directory){
+		fprintf(stderr, "Failed to open plugin search path %s: %s\n", path, strerror(errno));
+		return 1;
+	}
+
+	for(entry = readdir(directory); entry; entry = readdir(directory)){
+		if(strlen(entry->d_name) < 4 || strncmp(".so", entry->d_name + (strlen(entry->d_name) - 3), 3)){
+			continue;
+		}
+
+		if(fstatat(dirfd(directory), entry->d_name, &file_stat, 0) < 0){
+			fprintf(stderr, "Failed to stat %s: %s\n", entry->d_name, strerror(errno));
+			continue;
+		}
+
+		if(!S_ISREG(file_stat.st_mode)){
+			continue;
+		}
+
+		if(plugin_attach(path, entry->d_name)){
+			goto load_done;
+		}
+	}
+	rv = 0;
+
+load_done:
+	if(closedir(directory) < 0){
+		fprintf(stderr, "Failed to close plugin directory %s: %s\n", path, strerror(errno));
+		return -1;
+	}
+	return rv;
+#endif
+}
+
+int plugins_close(){
+	size_t u;
+
+	for(u = 0; u < plugins; u++){
+#ifdef _WIN32
+		char* error = NULL;
+		//FreeLibrary returns the inverse of dlclose
+		if(!FreeLibrary(plugin_handle[u])){
+			FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+				NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) &error, 0, NULL);
+			fprintf(stderr, "Failed to unload plugin: %s\n", error);
+			LocalFree(error);
+		}
+#else
+		if(dlclose(plugin_handle[u])){
+			fprintf(stderr, "Failed to unload plugin: %s\n", dlerror());
+		}
+#endif
+	}
+
+	free(plugin_handle);
+	plugins = 0;
+	return 0;
+}
-- 
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