/* Sysmon action-handling routines. */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netdb.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/time.h>

#include "action.h"
#include "etree.h"
#include "global.h"
#include "socketio.h"

/*************************************************************************/

/* List of all actions. */
Action *actlist;

/* Action which is currently being executed. */
Action *current_action;

/*************************************************************************/
/*************************************************************************/

static void do_setstate(ETree *arg)
{
    current_action->state = etree_eval_i(arg);
}

/*************************************************************************/

static void do_setmessage(ETree *arg)
{
    current_action->message = strdup(etree_eval_s(arg));
}

/*************************************************************************/

static void connect_callback(int sock, int status)
{
    Action *act;

    for (act = actlist; act; act = act->next) {
	if (act->sock == ~sock)
	    break;
    }
    if (!act) {
	sock_close(sock);
	return;
    }
    if (!(status & SOCKSTAT_OPEN)) {
	act->sock = NO_SOCK;
	act->connectstatus = 0;
	return;
    }
    act->sock = sock;
    act->connectstatus = 1;
}


static void do_connect(ETree **args, int nargs)
{
    int sock, len;
    char *str, buf[256];
    struct sockaddr_in sin;

    if (current_action->sock == NO_SOCK) {  /* Haven't yet tried to connect */
	struct hostent *he;
	struct protoent *pe;
	char *host = etree_eval_s(args[0]);
	int port = etree_eval_i(args[1]);

	if (!host || port <= 0 || port >= 65536)
	    return;
	pe = getprotobyname("tcp");
	if (!pe)
	    return;
	he = gethostbyname(host);
	if (!he)
	    return;
	sock = socket(AF_INET, SOCK_STREAM, pe->p_proto);
	if (sock < 0)
	    return;
	sin.sin_family = AF_INET;
	memcpy(&sin.sin_addr, he->h_addr_list[0], sizeof(sin.sin_addr));
	sin.sin_port = htons(port);
	current_action->sock = ~sock;
	gettimeofday(&current_action->connstart, NULL);
    } else if (current_action->sock < 0) {
	/* No need to initialize sockaddr... right? */
	sock = ~current_action->sock;
    } else {
	sock = current_action->sock;
    }

    current_action->connectdelay =
		tv_diff_milli(NULL, &current_action->connstart);
    if (current_action->connectdelay >= current_action->timeout) {
	sock_close(sock);
	current_action->sock = NO_SOCK;
	current_action->connectstatus = 0;
	return;
    }

    if (current_action->sock < 0) {	/* i.e. trying to connect */
	current_action->connectstatus = -1;
	sock_connect(sock, &sin, connect_callback);
	if (current_action->connectstatus < 0)
	    return;
	if (nargs < 4 || !args[3]) {
	    sock_close(sock);
	    current_action->sock = NO_SOCK;
	    return;
	}
	current_action->connectstatus = -1;
	str = etree_eval_s(args[2]);
	len = strlen(str);
	if (len > 0 && sock_write(sock, str, len) != len) {
	    sock_close(sock);
	    current_action->sock = NO_SOCK;
	    current_action->connectstatus = 0;
	    return;
	}
    }

    current_action->connectdelay =
		tv_diff_milli(NULL, &current_action->connstart);

    if (current_action->connectstatus != -2) {
	str = etree_eval_s(args[3]);
	if (!*str) {
	    sock_close(sock);
	    current_action->sock = NO_SOCK;
	    current_action->connectstatus = 1;
	    return;
	}
	len = strlen(str);
	if (len > sizeof(buf))
	    len = sizeof(buf);
	if (sock_read(sock, buf, len) != len) {
	    if (errno != EAGAIN) {
		current_action->connectstatus = 0;
		sock_close(sock);
		current_action->sock = NO_SOCK;
	    }
	    return;
	}
	current_action->connectdelay =
		tv_diff_milli(NULL, &current_action->connstart);
	if (strncmp(buf, str, len) != 0) {
	    current_action->connectstatus = 0;
	    sock_close(sock);
	    current_action->sock = NO_SOCK;
	    return;
	}
    }

    if (nargs < 5 || !args[4] || !etree_eval_i(args[4])) {
	current_action->connectstatus = 1;
	sock_close(sock);
	current_action->sock = NO_SOCK;
	return;
    }
    current_action->connectstatus = -2;
    while (sock_read(sock, buf, sizeof(buf)) == sizeof(buf))
	;
    current_action->connectdelay =
		tv_diff_milli(NULL, &current_action->connstart);
    if (errno != EAGAIN) {
	current_action->connectstatus = 1;
	sock_close(sock);
	current_action->sock = NO_SOCK;
    }
}

/*************************************************************************/

/* General action directive dispatcher. */

static void do_directive(ActionDirective *ad)
{
    switch (ad->what) {
	case AD_SETSTATE:	do_setstate(ad->args[0]);		break;
	case AD_SETMESSAGE:	do_setmessage(ad->args[0]);		break;
	case AD_CONNECT:	do_connect(ad->args, ad->nargs);	break;
    }
}

/*************************************************************************/
/*************************************************************************/

/* External interfaces. */

/*************************************************************************/

/* Allocate a new Action structure and link it to the global list. */

Action *act_new(void)
{
    Action *act = calloc(sizeof(Action), 1);
    act->next = actlist;
    if (actlist)
	actlist->prev = act;
    actlist = act;
    act->sock = NO_SOCK;
    return act;
}

/*************************************************************************/

/* Execute an action. */

void act_execute(Action *a)
{
    int i;

    current_action = a;
    for (i = a->dirlist_pos; i < a->dirlist_size; i++) {
	ActionDirective *ad = a->dirlist[i];
	if (ad->what == AD_IF) {
	    if (etree_eval_i(ad->args[0])) {
		/* Turn any corresponding ELSE into a NOELSE */
		ad = a->dirlist[i+1 + etree_eval_i(ad->args[1])];
		if (ad->what == AD_ELSE)
		    ad->what = AD_NOELSE;
	    } else {
		/* Skip this IF block */
		i += etree_eval_i(ad->args[1]);
	    }
	} else if (ad->what == AD_ELSE) {
	    /* Nothing */
	} else if (ad->what == AD_NOELSE) {
	    ad->what = AD_ELSE;
	    i += etree_eval_i(ad->args[0]);
	} else {
	    do_directive(ad);
	    if (a->connectstatus < 0)
		break;
	}
    }
    if (i == a->dirlist_size) {
	i = 0;
	gettimeofday(&a->lastexec, NULL);
    }
    gettimeofday(&a->lasttouch, NULL);
    a->dirlist_pos = i;
    current_action = NULL;
}

/*************************************************************************/

/* Free an action's data. */

void act_kill(Action *a)
{
    ActionDirective **ad;

    if (a->name)
	free(a->name);
    for (ad = a->dirlist; *ad; ad++)
	etree_free_list((*ad)->args, (*ad)->nargs);
    free(a->dirlist);
    free(a);
}

/*************************************************************************/

/* Find an action by name. */

Action *act_find(const char *name)
{
    Action *act;

    for (act = actlist; act; act = act->next) {
	if (act->name && strcasecmp(act->name, name) == 0)
	    return act;
    }
    return NULL;
}

/*************************************************************************/