output.c

/*
 * Copyright (C) 2016, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the license found in the LICENSE file in
 * the root directory of this source tree.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include <pthread.h>
#include <dlfcn.h>
#include <sys/socket.h>
#include <netinet/in.h>

#include <ncrx.h>

#include "include/common.h"
#include "include/msgbuf-struct.h"
#include "include/output.h"

static void *output_dlhandles[MAXOUTS];
static void (*outputs[MAXOUTS])(int, struct in6_addr *, struct msg_buf *,
		struct ncrx_msg *);
static int nr_outputs;

int register_output_module(char *path, int nr_workers)
{
	void *dl, *dlsym_addr;
	int (*mod_init)(int);
	int ret;

	if (nr_outputs == MAXOUTS) {
		warn("Too many output modules!\n");
		return -1;
	}

	log("Loading module '%s'\n", path);
	dl = dlopen(path, RTLD_NOW|RTLD_LOCAL);
	if (!dl) {
		warn("Can't open '%s': %s", path, dlerror());
		return -1;
	}

	dlsym_addr = dlsym(dl, "netconsd_output_handler");
	if (!dlsym_addr) {
		warn("Can't find handler sym in '%s': %s", path, dlerror());
		goto err_close;
	}

	mod_init = dlsym(dl, "netconsd_output_init");
	if (mod_init) {
		log("Calling mod_init() for '%s'\n", path);
		ret = mod_init(nr_workers);

		if (ret) {
			warn("mod_init() for '%s' failed: %d\n", path, ret);
			goto err_close;
		}
	}

	log("Module '%s' registered (#%d@%p)\n", path, nr_outputs, dlsym_addr);
	output_dlhandles[nr_outputs] = dl;
	outputs[nr_outputs] = dlsym_addr;
	nr_outputs++;
	return 0;

err_close:
	dlclose(dl);
	return -1;
}

void destroy_output_modules(void)
{
	int i, ret;
	void (*mod_exit)(void);
	char path[PATH_MAX] = {0};

	for (i = 0; i < nr_outputs; i++) {
		if (dlinfo(output_dlhandles[i], RTLD_DI_ORIGIN, path))
			strncpy(path, dlerror(), PATH_MAX - 1);

		mod_exit = dlsym(output_dlhandles[i], "netconsd_output_exit");
		if (mod_exit) {
			log("Calling mod_exit() for '%s'\n", path);
			mod_exit();
		}

		log("Unloading module '%s' (#%d@%p)\n", path, i, outputs[i]);
		ret = dlclose(output_dlhandles[i]);
		if (ret)
			warn("dlclose() failed: %s\n", dlerror());
	}
}

void execute_output_pipeline(int thread_nr, struct in6_addr *src,
		struct msg_buf *buf, struct ncrx_msg *msg)
{
	int i;

	for (i = 0; i < nr_outputs; i++)
		outputs[i](thread_nr, src, buf, msg);
}