/* sharkd_daemon.c
 *
 * Copyright (C) 2016 Jakub Zawadzki
 *
 * Wireshark - Network traffic analyzer
 * By Gerald Combs <gerald@wireshark.org>
 * Copyright 1998 Gerald Combs
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 */

#include <config.h>

#include <glib.h>

#include <stdio.h>
#include <errno.h>
#include <stddef.h>
#include <stdlib.h>
#include <signal.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef _WIN32
#include <wsutil/unicode-utils.h>
#include <wsutil/filesystem.h>
#include <wsutil/win32-utils.h>
#endif

#include <wsutil/socket.h>
#include <wsutil/inet_addr.h>
#include <wsutil/please_report_bug.h>

#ifndef _WIN32
#include <sys/un.h>
#include <netinet/tcp.h>
#endif

#include <wsutil/strtoi.h>

#include "sharkd.h"

#ifdef _WIN32
/* for windows support TCP sockets */
# define SHARKD_TCP_SUPPORT
#else
/* for other system support only local sockets */
# define SHARKD_UNIX_SUPPORT
#endif

static int _use_stdinout = 0;
static socket_handle_t _server_fd = INVALID_SOCKET;

static socket_handle_t
socket_init(char *path)
{
	socket_handle_t fd = INVALID_SOCKET;
	char *err_msg;

	err_msg = ws_init_sockets();
	if (err_msg != NULL) {
		g_warning("ERROR: %s", err_msg);
		g_free(err_msg);
		g_warning("%s", please_report_bug());
		return fd;
	}

#ifdef SHARKD_UNIX_SUPPORT
	if (!strncmp(path, "unix:", 5))
	{
		struct sockaddr_un s_un;
		socklen_t s_un_len;

		path += 5;

		if (strlen(path) + 1 > sizeof(s_un.sun_path))
			return INVALID_SOCKET;

		fd = socket(AF_UNIX, SOCK_STREAM, 0);
		if (fd == INVALID_SOCKET)
			return INVALID_SOCKET;

		memset(&s_un, 0, sizeof(s_un));
		s_un.sun_family = AF_UNIX;
		g_strlcpy(s_un.sun_path, path, sizeof(s_un.sun_path));

		s_un_len = (socklen_t)(offsetof(struct sockaddr_un, sun_path) + strlen(s_un.sun_path));

		if (s_un.sun_path[0] == '@')
			s_un.sun_path[0] = '\0';

		if (bind(fd, (struct sockaddr *) &s_un, s_un_len))
		{
			closesocket(fd);
			return INVALID_SOCKET;
		}
	}
	else
#endif

#ifdef SHARKD_TCP_SUPPORT
	if (!strncmp(path, "tcp:", 4))
	{
		struct sockaddr_in s_in;
		int one = 1;
		char *port_sep;
		guint16 port;

		path += 4;

		port_sep = strchr(path, ':');
		if (!port_sep)
			return INVALID_SOCKET;

		*port_sep = '\0';

		if (ws_strtou16(port_sep + 1, NULL, &port) == FALSE)
			return INVALID_SOCKET;

#ifdef _WIN32
		/* Need to use WSASocket() to disable overlapped I/O operations,
		   this way on windows SOCKET can be used as HANDLE for stdin/stdout */
		fd = WSASocket(AF_INET, SOCK_STREAM, 0, NULL, 0, 0);
#else
		fd = socket(AF_INET, SOCK_STREAM, 0);
#endif
		if (fd == INVALID_SOCKET)
			return INVALID_SOCKET;

		s_in.sin_family = AF_INET;
		ws_inet_pton4(path, &(s_in.sin_addr.s_addr));
		s_in.sin_port = g_htons(port);
		*port_sep = ':';

		setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (void *) &one, sizeof(one));

		if (bind(fd, (struct sockaddr *) &s_in, sizeof(struct sockaddr_in)))
		{
			closesocket(fd);
			return INVALID_SOCKET;
		}
	}
	else
#endif
	{
		return INVALID_SOCKET;
	}

	if (listen(fd, SOMAXCONN))
	{
		closesocket(fd);
		return INVALID_SOCKET;
	}

	return fd;
}

int
sharkd_init(int argc, char **argv)
{
#ifndef _WIN32
	pid_t pid;
#endif
	socket_handle_t fd;

	if (argc != 2)
	{
		fprintf(stderr, "Usage: %s <-|socket>\n", argv[0]);
		fprintf(stderr, "\n");

		fprintf(stderr, "<socket> examples:\n");
#ifdef SHARKD_UNIX_SUPPORT
		fprintf(stderr, " - unix:/tmp/sharkd.sock - listen on unix file /tmp/sharkd.sock\n");
#endif
#ifdef SHARKD_TCP_SUPPORT
		fprintf(stderr, " - tcp:127.0.0.1:4446 - listen on TCP port 4446\n");
#endif
		fprintf(stderr, "\n");
		return -1;
	}

#ifndef _WIN32
	signal(SIGCHLD, SIG_IGN);
#endif

	if (!strcmp(argv[1], "-"))
	{
		_use_stdinout = 1;
	}
	else
	{
		fd = socket_init(argv[1]);
		if (fd == INVALID_SOCKET)
			return -1;
		_server_fd = fd;
	}

	if (!_use_stdinout)
	{
		/* all good - try to daemonize */
#ifndef _WIN32
		pid = fork();
		if (pid == -1)
			fprintf(stderr, "cannot go to background fork() failed: %s\n", g_strerror(errno));

		if (pid != 0)
		{
			/* parent */
			exit(0);
		}
#endif
	}

	return 0;
}

int
sharkd_loop(void)
{
	if (_use_stdinout)
	{
		return sharkd_session_main();
	}

	while (1)
	{
#ifndef _WIN32
		pid_t pid;
#else
		PROCESS_INFORMATION pi;
		STARTUPINFO si;
		char *exename;
#endif
		socket_handle_t fd;

		fd = accept(_server_fd, NULL, NULL);
		if (fd == INVALID_SOCKET)
		{
			fprintf(stderr, "cannot accept(): %s\n", g_strerror(errno));
			continue;
		}

		/* wireshark is not ready for handling multiple capture files in single process, so fork(), and handle it in separate process */
#ifndef _WIN32
		pid = fork();
		if (pid == 0)
		{
			closesocket(_server_fd);
			/* redirect stdin, stdout to socket */
			dup2(fd, 0);
			dup2(fd, 1);
			close(fd);

			exit(sharkd_session_main());
		}

		if (pid == -1)
		{
			fprintf(stderr, "cannot fork(): %s\n", g_strerror(errno));
		}

#else
		memset(&pi, 0, sizeof(pi));
		memset(&si, 0, sizeof(si));

		si.cb = sizeof(si);
		si.dwFlags = STARTF_USESTDHANDLES | STARTF_USESHOWWINDOW;
		si.hStdInput = (HANDLE) fd;
		si.hStdOutput = (HANDLE) fd;
		si.hStdError = GetStdHandle(STD_ERROR_HANDLE);

		exename = g_strdup_printf("%s\\%s", get_progfile_dir(), "sharkd.exe");

		if (!win32_create_process(exename, "sharkd.exe -", NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi))
		{
			fprintf(stderr, "win32_create_process(%s) failed\n", exename);
		}
		else
		{
			CloseHandle(pi.hThread);
		}

		g_free(exename);
#endif

		closesocket(fd);
	}
	return 0;
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */