/*****************************************************************************
* 
* Nagios check_pgsql plugin
* 
* License: GPL
* Copyright (c) 1999-2007 Nagios Plugins Development Team
* 
* Description:
* 
* This file contains the check_pgsql plugin
* 
* Test whether a PostgreSQL Database is accepting connections.
* 
* 
* 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 3 of the License, or
* (at your option) any later version.
* 
* This program 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, see <http://www.gnu.org/licenses/>.
* 
* 
*****************************************************************************/

const char *progname = "check_pgsql";
const char *copyright = "1999-2007";
const char *email = "nagiosplug-devel@lists.sourceforge.net";

#include "common.h"
#include "utils.h"

#include "netutils.h"
#include <libpq-fe.h>
#include <pg_config_manual.h>

#define DEFAULT_DB "template1"
#define DEFAULT_HOST "127.0.0.1"

enum {
	DEFAULT_PORT = 5432,
	DEFAULT_WARN = 2,
	DEFAULT_CRIT = 8
};



int process_arguments (int, char **);
int validate_arguments (void);
void print_usage (void);
void print_help (void);
int is_pg_dbname (char *);
int is_pg_logname (char *);

char *pghost = NULL;						/* host name of the backend server */
char *pgport = NULL;						/* port of the backend server */
int default_port = DEFAULT_PORT;
char *pgoptions = NULL;
char *pgtty = NULL;
char dbName[NAMEDATALEN] = DEFAULT_DB;
char *pguser = NULL;
char *pgpasswd = NULL;
double twarn = (double)DEFAULT_WARN;
double tcrit = (double)DEFAULT_CRIT;
int verbose = 0;

PGconn *conn;
/*PGresult   *res;*/


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

The (psuedo?)literate programming XML is contained within \@\@\- <XML> \-\@\@
tags in the comments. With in the tags, the XML is assembled sequentially.
You can define entities in tags. You also have all the #defines available as
entities.

Please note that all tags must be lowercase to use the DocBook XML DTD.

@@-<article>

<sect1>
<title>Quick Reference</title>
<!-- The refentry forms a manpage -->
<refentry>
<refmeta>
<manvolnum>5<manvolnum>
</refmeta>
<refnamdiv>
<refname>&progname;</refname>
<refpurpose>&SUMMARY;</refpurpose>
</refnamdiv>
</refentry>
</sect1>

<sect1>
<title>FAQ</title>
</sect1>

<sect1>
<title>Theory, Installation, and Operation</title>

<sect2>
<title>General Description</title>
<para>
&DESCRIPTION;
</para>
</sect2>

<sect2>
<title>Future Enhancements</title>
<para>ToDo List</para>
<itemizedlist>
<listitem>Add option to get password from a secured file rather than the command line</listitem>
<listitem>Add option to specify the query to execute</listitem>
</itemizedlist>
</sect2>


<sect2>
<title>Functions</title>
-@@
******************************************************************************/



int
main (int argc, char **argv)
{
	int elapsed_time;
	int status = STATE_UNKNOWN;

	/* begin, by setting the parameters for a backend connection if the
	 * parameters are null, then the system will try to use reasonable
	 * defaults by looking up environment variables or, failing that,
	 * using hardwired constants */

	pgoptions = NULL;  /* special options to start up the backend server */
	pgtty = NULL;      /* debugging tty for the backend server */

	setlocale (LC_ALL, "");
	bindtextdomain (PACKAGE, LOCALEDIR);
	textdomain (PACKAGE);

	/* Parse extra opts if any */
	argv=np_extra_opts (&argc, argv, progname);

	if (process_arguments (argc, argv) == ERROR)
		usage4 (_("Could not parse arguments"));
	if (verbose > 2)
		printf("Arguments initialized\n");

	/* Set signal handling and alarm */
	if (signal (SIGALRM, timeout_alarm_handler) == SIG_ERR) {
		usage4 (_("Cannot catch SIGALRM"));
	}
	alarm (timeout_interval);

	if (verbose)
		printf("Connecting to database:\n DB: %s\n User: %s\n Host: %s\n Port: %d\n", dbName,
		(pguser != NULL) ? pguser : "unspecified",
		(pghost != NULL) ? pghost : "unspecified",
		(pgport != NULL) ? atoi(pgport) : DEFAULT_PORT);

	/* make a connection to the database */
	time (&start_time);
	conn =
		PQsetdbLogin (pghost, pgport, pgoptions, pgtty, dbName, pguser, pgpasswd);
	time (&end_time);
	elapsed_time = (int) (end_time - start_time);
	if (verbose)
		printf("Time elapsed: %d\n", elapsed_time);

	/* check to see that the backend connection was successfully made */
	if (verbose)
		printf("Verifying connection\n");
	if (PQstatus (conn) == CONNECTION_BAD) {
		printf (_("CRITICAL - no connection to '%s' (%s).\n"),
		        dbName,	PQerrorMessage (conn));
		PQfinish (conn);
		return STATE_CRITICAL;
	}
	else if (elapsed_time > tcrit) {
		status = STATE_CRITICAL;
	}
	else if (elapsed_time > twarn) {
		status = STATE_WARNING;
	}
	else {
		status = STATE_OK;
	}
	if (verbose)
		printf("Closing connection\n");
	PQfinish (conn);
	printf (_(" %s - database %s (%d sec.)|%s\n"),
	        state_text(status), dbName, elapsed_time,
	        fperfdata("time", elapsed_time, "s",
	                 (int)twarn, twarn, (int)tcrit, tcrit, TRUE, 0, FALSE,0));
	return status;
}



/* process command-line arguments */
int
process_arguments (int argc, char **argv)
{
	int c;

	int option = 0;
	static struct option longopts[] = {
		{"help", no_argument, 0, 'h'},
		{"version", no_argument, 0, 'V'},
		{"timeout", required_argument, 0, 't'},
		{"critical", required_argument, 0, 'c'},
		{"warning", required_argument, 0, 'w'},
		{"hostname", required_argument, 0, 'H'},
		{"logname", required_argument, 0, 'l'},
		{"password", required_argument, 0, 'p'},
		{"authorization", required_argument, 0, 'a'},
		{"port", required_argument, 0, 'P'},
		{"database", required_argument, 0, 'd'},
		{"verbose", no_argument, 0, 'v'},
		{0, 0, 0, 0}
	};

	while (1) {
		c = getopt_long (argc, argv, "hVt:c:w:H:P:d:l:p:a:v",
		                 longopts, &option);

		if (c == EOF)
			break;

		switch (c) {
		case '?':     /* usage */
			usage5 ();
		case 'h':     /* help */
			print_help ();
			exit (STATE_OK);
		case 'V':     /* version */
			print_revision (progname, NP_VERSION);
			exit (STATE_OK);
		case 't':     /* timeout period */
			if (!is_integer (optarg))
				usage2 (_("Timeout interval must be a positive integer"), optarg);
			else
				timeout_interval = atoi (optarg);
			break;
		case 'c':     /* critical time threshold */
			if (!is_nonnegative (optarg))
				usage2 (_("Critical threshold must be a positive integer"), optarg);
			else
				tcrit = strtod (optarg, NULL);
			break;
		case 'w':     /* warning time threshold */
			if (!is_nonnegative (optarg))
				usage2 (_("Warning threshold must be a positive integer"), optarg);
			else
				twarn = strtod (optarg, NULL);
			break;
		case 'H':     /* host */
			if (!is_host (optarg))
				usage2 (_("Invalid hostname/address"), optarg);
			else
				pghost = optarg;
			break;
		case 'P':     /* port */
			if (!is_integer (optarg))
				usage2 (_("Port must be a positive integer"), optarg);
			else
				pgport = optarg;
			break;
		case 'd':     /* database name */
			if (!is_pg_dbname (optarg)) /* checks length and valid chars */
				usage2 (_("Database name is not valid"), optarg);
			else /* we know length, and know optarg is terminated, so us strcpy */
				strcpy (dbName, optarg);
			break;
		case 'l':     /* login name */
			if (!is_pg_logname (optarg))
				usage2 (_("User name is not valid"), optarg);
			else
				pguser = optarg;
			break;
		case 'p':     /* authentication password */
		case 'a':
			pgpasswd = optarg;
			break;
		case 'v':
			verbose++;
			break;
		}
	}

	return validate_arguments ();
}


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

@@-
<sect3>
<title>validate_arguments</title>

<para>&PROTO_validate_arguments;</para>

<para>Given a database name, this function returns TRUE if the string
is a valid PostgreSQL database name, and returns false if it is
not.</para>

<para>Valid PostgreSQL database names are less than &NAMEDATALEN;
characters long and consist of letters, numbers, and underscores. The
first character cannot be a number, however.</para>

</sect3>
-@@
******************************************************************************/



int
validate_arguments ()
{
	return OK;
}


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

@@-
<sect3>
<title>is_pg_dbname</title>

<para>&PROTO_is_pg_dbname;</para>

<para>Given a database name, this function returns TRUE if the string
is a valid PostgreSQL database name, and returns false if it is
not.</para>

<para>Valid PostgreSQL database names are less than &NAMEDATALEN;
characters long and consist of letters, numbers, and underscores. The
first character cannot be a number, however.</para>

</sect3>
-@@
******************************************************************************/



int
is_pg_dbname (char *dbname)
{
	char txt[NAMEDATALEN];
	char tmp[NAMEDATALEN];
	if (strlen (dbname) > NAMEDATALEN - 1)
		return (FALSE);
	strncpy (txt, dbname, NAMEDATALEN - 1);
	txt[NAMEDATALEN - 1] = 0;
	if (sscanf (txt, "%[_a-zA-Z]%[^_a-zA-Z0-9-]", tmp, tmp) == 1)
		return (TRUE);
	if (sscanf (txt, "%[_a-zA-Z]%[_a-zA-Z0-9-]%[^_a-zA-Z0-9-]", tmp, tmp, tmp) ==
			2) return (TRUE);
	return (FALSE);
}

/**

the tango program should eventually create an entity here based on the
function prototype

@@-
<sect3>
<title>is_pg_logname</title>

<para>&PROTO_is_pg_logname;</para>

<para>Given a username, this function returns TRUE if the string is a
valid PostgreSQL username, and returns false if it is not. Valid PostgreSQL
usernames are less than &NAMEDATALEN; characters long and consist of
letters, numbers, dashes, and underscores, plus possibly some other
characters.</para>

<para>Currently this function only checks string length. Additional checks
should be added.</para>

</sect3>
-@@
******************************************************************************/



int
is_pg_logname (char *username)
{
	if (strlen (username) > NAMEDATALEN - 1)
		return (FALSE);
	return (TRUE);
}

/******************************************************************************
@@-
</sect2>
</sect1>
</article>
-@@
******************************************************************************/



void
print_help (void)
{
	char *myport;

	asprintf (&myport, "%d", DEFAULT_PORT);

	print_revision (progname, NP_VERSION);

	printf (COPYRIGHT, copyright, email);

	printf (_("Test whether a PostgreSQL Database is accepting connections."));

	printf ("\n\n");

	print_usage ();

	printf (UT_HELP_VRSN);
	printf (UT_EXTRA_OPTS);

	printf (UT_HOST_PORT, 'P', myport);

	printf (UT_IPv46);

	printf (" %s\n", "-d, --database=STRING");
	printf ("    %s", _("Database to check "));
	printf (_("(default: %s)"), DEFAULT_DB);
	printf (" %s\n", "-l, --logname = STRING");
	printf ("    %s\n", _("Login name of user"));
	printf (" %s\n", "-p, --password = STRING");
	printf ("    %s\n", _("Password (BIG SECURITY ISSUE)"));

	printf (UT_WARN_CRIT);

	printf (UT_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);

	printf (UT_VERBOSE);

	printf ("\n");
	printf (" %s\n", _("All parameters are optional."));
	printf (" %s\n", _("This plugin tests a PostgreSQL DBMS to determine whether it is active and"));
	printf (" %s\n", _("accepting queries. In its current operation, it simply connects to the"));
	printf (" %s\n", _("specified database, and then disconnects. If no database is specified, it"));
	printf (" %s\n", _("connects to the template1 database, which is present in every functioning"));
	printf (" %s\n\n", _("PostgreSQL DBMS."));

	printf (" %s\n", _("The plugin will connect to a local postmaster if no host is specified. To"));
	printf (" %s\n", _("connect to a remote host, be sure that the remote postmaster accepts TCP/IP"));
	printf (" %s\n\n", _("connections (start the postmaster with the -i option)."));

	printf (" %s\n", _("Typically, the nagios user (unless the --logname option is used) should be"));
	printf (" %s\n", _("able to connect to the database without a password. The plugin can also send"));
	printf (" %s\n", _("a password, but no effort is made to obsure or encrypt the password."));

#ifdef NP_EXTRA_OPTS
	printf ("\n");
	printf ("%s\n", _("Notes:"));
	printf (UT_EXTRA_OPTS_NOTES);
#endif

	printf (UT_SUPPORT);
}



void
print_usage (void)
{
	printf (_("Usage:"));
	printf ("%s [-H <host>] [-P <port>] [-c <critical time>] [-w <warning time>]\n", progname);
	printf (" [-t <timeout>] [-d <database>] [-l <logname>] [-p <password>]\n");
}