Move to dynamically loading backends

1 files changed, 110 insertions, 0 deletions

diff --git a/plugin.c b/plugin.c
new file mode 100644
index 0000000..561e131
--- /dev/null
+++ b/plugin.c
@@ -0,0 +1,110 @@
+#include <stdio.h>
+#include <string.h>
+#include <dlfcn.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include "plugin.h"
+
+size_t plugins = 0;
+void** plugin_handle = NULL;
+
+static int plugin_attach(char* path, char* file){
+	plugin_init init = NULL;
+	void* handle = NULL;
+
+	char* lib = calloc(strlen(path) + strlen(file) + 1, sizeof(char));
+	if(!lib){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return 1;
+	}
+
+	snprintf(lib, strlen(path) + strlen(file) + 1, "%s%s", path, file);
+
+	handle = dlopen(lib, RTLD_NOW);
+	if(!handle){
+		fprintf(stderr, "Failed to load plugin %s: %s\n", lib, dlerror());
+		free(lib);
+		return 0;
+	}
+
+	init = dlsym(handle, "init");
+	if(init){
+		if(init()){
+			fprintf(stderr, "Plugin %s failed to initialize\n", lib);
+			dlclose(handle);
+			free(lib);
+			return 1;
+		}
+	}
+	else{
+		return 0;
+	}
+
+	plugin_handle = realloc(plugin_handle, (plugins + 1) * sizeof(void*));
+	if(!plugin_handle){
+		fprintf(stderr, "Failed to allocate memory\n");
+		dlclose(handle);
+		free(lib);
+		return 1;
+	}
+
+	plugin_handle[plugins] = handle;
+	plugins++;
+
+	return 0;
+}
+
+int plugins_load(char* path){
+	int rv = -1;
+
+	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(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(!(file_stat.st_mode & S_IXUSR)){
+			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;
+}
+
+int plugins_close(){
+	size_t u;
+	for(u = 0; u < plugins; u++){
+		if(dlclose(plugin_handle[u])){
+			fprintf(stderr, "Failed to unload plugin: %s\n", dlerror());
+		}
+	}
+
+	free(plugin_handle);
+	plugins = 0;
+	return 0;
+}