/* 
	 * Copyright (C) 2014 Philipp Marek <philipp.marek@linbit.com>
	 * 
	 * This program is free software; you can redistribute it and/or
	 * modify it under the terms of the GNU General Public
	 * License as published by the Free Software Foundation; either
	 * version 2 of the License, or (at your option) any later version.
	 * 
	 * This software is distributed in the hope that it will be useful,
	 * but WITHOUT ANY WARRANTY; without even the implied warranty of
	 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	 * General Public License for more details.
	 * 
	 * You should have received a copy of the GNU General Public License along
	 * with this program; if not, write to the Free Software Foundation, Inc.,
	 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	 */
	
	#include <stdlib.h>
	#include <string.h>
	#include <errno.h>
	#include <arpa/inet.h>
	#include <signal.h>
	#include <sys/wait.h>
	#include <inttypes.h>
	#include <dirent.h>
	#include <stdio.h>
	#include <assert.h>
	#include <time.h>
	#include "ticket.h"
	#include "config.h"
	#include "inline-fn.h"
	#include "log.h"
	#include "pacemaker.h"
	#include "booth.h"
	#include "handler.h"
	
	static int set_booth_env(struct ticket_config *tk)
	{
		int rv;
		char expires[16];
	
		sprintf(expires, "%" PRId64, (int64_t)wall_ts(&tk->term_expires));
		rv = setenv("BOOTH_TICKET", tk->name, 1) ||
			setenv("BOOTH_LOCAL", local->addr_string, 1) ||
			setenv("BOOTH_CONF_NAME", booth_conf->name, 1) ||
			setenv("BOOTH_CONF_PATH", cl.configfile, 1) ||
			setenv("BOOTH_TICKET_EXPIRES", expires, 1);
	
		if (rv) {
			log_error("Cannot set environment: %s", strerror(errno));
		}
		return rv;
	}
	
	static void
	closefiles(void)
	{
		int fd;
	
		/* close all descriptors except stdin/out/err */
		for (fd = getdtablesize() - 1; fd > STDERR_FILENO; fd--) {
			close(fd);
		}
	}
	
	static void
	run_ext_prog(struct ticket_config *tk, char *prog)
	{
		if (set_booth_env(tk)) {
			_exit(1);
		}
		closefiles(); /* don't leak open files */
		tk_log_debug("running handler %s", prog);
		execv(prog, tk_test.argv);
		tk_log_error("%s: execv failed (%s)", prog, strerror(errno));
		_exit(1);
	}
	
	static int
	prog_filter(const struct dirent *dp)
	{
		return (*dp->d_name != '.');
	}
	
	static pid_t curr_pid;
	static int ignore_status;
	
	static int
	test_exit_status(struct ticket_config *tk, char *prog, int status, int log_msg)
	{
		int rv = -1;
	
		if (WIFEXITED(status)) {
			rv = WEXITSTATUS(status);
		} else if (WIFSIGNALED(status)) {
			rv = 128 + WTERMSIG(status);
		}
		if (rv) {
			if (log_msg) {
				tk_log_warn("handler \"%s\" failed: %s",
					prog, interpret_rv(status));
				tk_log_warn("we are not allowed to acquire ticket");
			}
		} else {
			tk_log_debug("handler \"%s\" exited with success",
				prog);
		}
		return rv;
	}
	
	static void
	reset_test_state(struct ticket_config *tk)
	{
		tk_test.pid = 0;
		set_progstate(tk, EXTPROG_IDLE);
	}
	
	int tk_test_exit_status(struct ticket_config *tk)
	{
		int rv;
	
		rv = test_exit_status(tk, tk_test.path, tk_test.status, !tk_test.is_dir);
		reset_test_state(tk);
		return rv;
	}
	
	void wait_child(int sig)
	{
		int i, status;
		struct ticket_config *tk;
	
		/* use waitpid(2) and not wait(2) in order not to interfere
		 * with popen(2)/pclose(2) and system(2) used in pacemaker.c
		 */
		_FOREACH_TICKET(i, tk) {
			if (tk_test.path && tk_test.pid > 0 &&
					(tk_test.progstate == EXTPROG_RUNNING ||
					tk_test.progstate == EXTPROG_IGNORE) &&
					waitpid(tk_test.pid, &status, WNOHANG) == tk_test.pid) {
				if (tk_test.progstate == EXTPROG_IGNORE) {
					/* not interested in the outcome */
					reset_test_state(tk);
				} else {
					tk_test.status = status;
					set_progstate(tk, EXTPROG_EXITED);
				}
			}
		}
	}
	
	/* the parent may want to have us stop processing scripts, say
	 * when the ticket gets revoked
	 */
	static void ignore_rest(int sig)
	{
		signal(SIGTERM, SIG_IGN);
		ignore_status = 1;
		if (curr_pid > 0) {
			(void)kill(curr_pid, SIGTERM);
		}
	}
	
	void ext_prog_timeout(struct ticket_config *tk)
	{
		tk_log_warn("handler timed out");
	}
	
	int is_ext_prog_running(struct ticket_config *tk)
	{
		if (!tk_test.path)
			return 0;
		return (tk_test.pid > 0 && tk_test.progstate == EXTPROG_RUNNING);
	}
	
	void ignore_ext_test(struct ticket_config *tk)
	{
		if (is_ext_prog_running(tk)) {
			(void)kill(tk_test.pid, SIGTERM);
			set_progstate(tk, EXTPROG_IGNORE);
		} else if (tk_test.progstate == EXTPROG_EXITED) {
			/* external prog exited, but the status not yet examined;
			 * we're not interested in checking the status anymore */
			reset_test_state(tk);
		}
	}
	
	static void
	process_ext_dir(struct ticket_config *tk)
	{
		char prog[FILENAME_MAX+1];
		int rv, n_progs, i, status;

		struct dirent **proglist, *dp;
	
		signal(SIGTERM, (__sighandler_t)ignore_rest);
		signal(SIGCHLD, SIG_DFL);
		signal(SIGUSR1, SIG_DFL);
		signal(SIGINT, SIG_DFL);

		tk_log_debug("running programs in directory %s", tk_test.path);

		n_progs = scandir(tk_test.path, &proglist, prog_filter, alphasort);
		if (n_progs == -1) {
			tk_log_error("%s: scandir failed (%s)", tk_test.path, strerror(errno));
			_exit(1);
		}
		for (i = 0; i < n_progs; i++) {
			if (ignore_status)
				break;
			dp = proglist[i];
			if (strlen(dp->d_name) + strlen(tk_test.path) + 1 > FILENAME_MAX) {
				tk_log_error("%s: name exceeds max length (%s)",
					tk_test.path, dp->d_name);
				_exit(1);
			}
			strcpy(prog, tk_test.path);
			strcat(prog, "/");
			strcat(prog, dp->d_name);
			switch(curr_pid=fork()) {
			case -1:
				log_error("fork: %s", strerror(errno));
				_exit(1);
			case 0: /* child */
				run_ext_prog(tk, prog);
				break;  /* run_ext_prog effectively noreturn */
			default: /* parent */
				while (waitpid(curr_pid, &status, 0) != curr_pid)
					;
				curr_pid = 0;
				if (!ignore_status) {
					rv = test_exit_status(tk, prog, status, 1);
					if (rv)
						_exit(rv);
				} else {
					/*
					 * To make ignore_rest function signal safe log_info
					 * must be removed from signal function. Information
					 * about signal delivery is important so put it here.
					 */
					log_info("external programs handler caught TERM, ignoring "
					    "status of external test programs");
				}
			}
		}
		_exit(0);
	}
	
	/* run some external program
	 * return codes:
	 * RUNCMD_ERR: executing program failed (or some other failure)
	 * RUNCMD_MORE: program forked, results later
	 */
	int run_handler(struct ticket_config *tk)
	{
		int rv = 0;
		pid_t pid;
		struct stat stbuf;
	
		if (!tk_test.path)
			return 0;
	
		if (stat(tk_test.path, &stbuf)) {
			tk_log_error("%s: stat failed (%s)", tk_test.path, strerror(errno));
			return RUNCMD_ERR;
		}
		tk_test.is_dir = (stbuf.st_mode & S_IFDIR);
	
		switch(pid=fork()) {
		case -1:
			log_error("fork: %s", strerror(errno));
			return RUNCMD_ERR;
		case 0: /* child */
			if (tk_test.is_dir) {
				process_ext_dir(tk);
			} else {
				run_ext_prog(tk, tk_test.path);
			}
		default: /* parent */
			tk_test.pid = pid;
			set_progstate(tk, EXTPROG_RUNNING);
			rv = RUNCMD_MORE; /* program runs */
		}
	
		return rv;
	}