/*****************************************************************************
* 
* Nagios check_pgsql plugin
* 
* License: GPL
* Copyright (c) 1999-2014 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 = "1999-2014";
const char *email = "devel@nagios-plugins.org";

#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"

/* return the PSQL server version as a 3-tuple */
#define PSQL_SERVER_VERSION3(server_version) \
	(server_version) / 10000, \
	(server_version) / 100 - (int)((server_version) / 10000) * 100, \
	(server_version) - (int)((server_version) / 100) * 100
/* return true if the given host is a UNIX domain socket */
#define PSQL_IS_UNIX_DOMAIN_SOCKET(host) \
	((NULL == (host)) || ('\0' == *(host)) || ('/' == *(host)))
/* return a 3-tuple identifying a host/port independent of the socket type */
#define PSQL_SOCKET3(host, port) \
	((NULL == (host)) || ('\0' == *(host))) ? DEFAULT_PGSOCKET_DIR : host, \
	PSQL_IS_UNIX_DOMAIN_SOCKET (host) ? "/.s.PGSQL." : ":", \
	port

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 *);
int do_query (PGconn *, 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;
char *pgparams = NULL;
double twarn = (double)DEFAULT_WARN;
double tcrit = (double)DEFAULT_CRIT;
char *pgquery = NULL;
char *query_warning = NULL;
char *query_critical = NULL;
static int print_query = 0;
thresholds *qthresholds = NULL;
int verbose = 0;

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

The (pseudo?)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>
</sect2>


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



int
main (int argc, char **argv)
{
	PGconn *conn;
	char *conninfo = NULL;

	struct timeval start_timeval;
	struct timeval end_timeval;
	double elapsed_time;
	int status = STATE_UNKNOWN;
	int query_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 (pgparams)
		asprintf (&conninfo, "%s ", pgparams);

	asprintf (&conninfo, "%sdbname = '%s'", conninfo ? conninfo : "", dbName);
	if (pghost)
		asprintf (&conninfo, "%s host = '%s'", conninfo, pghost);
	if (pgport)
		asprintf (&conninfo, "%s port = '%s'", conninfo, pgport);
	if (pgoptions)
		asprintf (&conninfo, "%s options = '%s'", conninfo, pgoptions);
	/* if (pgtty) -- ignored by PQconnectdb */
	if (pguser)
		asprintf (&conninfo, "%s user = '%s'", conninfo, pguser);

	if (verbose) /* do not include password (see right below) in output */
		printf ("Connecting to PostgreSQL using conninfo: %s%s\n", conninfo,
				pgpasswd ? " password = <hidden>" : "");

	if (pgpasswd)
		asprintf (&conninfo, "%s password = '%s'", conninfo, pgpasswd);

	/* make a connection to the database */
	gettimeofday (&start_timeval, NULL);
	conn = PQconnectdb (conninfo);
	gettimeofday (&end_timeval, NULL);

	while (start_timeval.tv_usec > end_timeval.tv_usec) {
		--end_timeval.tv_sec;
		end_timeval.tv_usec += 1000000;
	}
	elapsed_time = (double)(end_timeval.tv_sec - start_timeval.tv_sec)
		+ (double)(end_timeval.tv_usec - start_timeval.tv_usec) / 1000000.0;

	if (verbose)
		printf("Time elapsed: %f\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) {
		char *server_host = PQhost (conn);
		int server_version = PQserverVersion (conn);

		printf ("Successfully connected to database %s (user %s) "
				"at server %s%s%s (server version: %d.%d.%d, "
				"protocol version: %d, pid: %d)\n",
				PQdb (conn), PQuser (conn),
				PSQL_SOCKET3 (server_host, PQport (conn)),
				PSQL_SERVER_VERSION3 (server_version),
				PQprotocolVersion (conn), PQbackendPID (conn));
	}

	printf (_(" %s - database %s (%f sec.)|%s\n"),
	        state_text(status), dbName, elapsed_time,
	        fperfdata("time", elapsed_time, "s",
	                 !!(twarn > 0.0), twarn, !!(tcrit > 0.0), tcrit, TRUE, 0, FALSE,0));

	if (pgquery)
		query_status = do_query (conn, pgquery);

	if (verbose)
		printf("Closing connection\n");
	PQfinish (conn);
	return (pgquery && query_status > status) ? query_status : 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'},
		{"option", required_argument, 0, 'o'},
		{"query", required_argument, 0, 'q'},
		{"query_critical", required_argument, 0, 'C'},
		{"query_warning", required_argument, 0, 'W'},
		{"print-query", no_argument, 0, 'r'},
		{"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:o:q:C:W: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 */
			timeout_interval = parse_timeout_string (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 'C':     /* critical query threshold */
			query_critical = optarg;
			break;
		case 'W':     /* warning query threshold */
			query_warning = optarg;
			break;
		case 'r':
			print_query = 1;
			break;
		case 'H':     /* host */
			if ((*optarg != '/') && (!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 'o':
			if (pgparams)
				asprintf (&pgparams, "%s %s", pgparams, optarg);
			else
				asprintf (&pgparams, "%s", optarg);
			break;
		case 'q':
			pgquery = optarg;
			break;
		case 'v':
			verbose++;
			break;
		}
	}

	set_thresholds (&qthresholds, query_warning, query_critical);

	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;

	xasprintf (&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 (" %s\n", "-d, --database=STRING");
	printf ("    %s", _("Database to check "));
	printf (_("(default: %s)\n"), DEFAULT_DB);
	printf (" %s\n", "-l, --logname = STRING");
	printf ("    %s\n", _("Login name of user"));
	printf (" %s\n", "-p, --password = STRING");
	printf ("    %s\n", _("The user's password. To avoid security issues, define this option using"));
	printf ("    %s\n", _("--extra-opts when possible."));
	printf (" %s\n", "-o, --option = STRING");
	printf ("    %s\n", _("Connection parameters (keyword = value), see below"));

	printf (UT_WARN_CRIT);

	printf (UT_CONN_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);

	printf (" %s\n", "-q, --query=STRING");
	printf ("    %s\n", _("SQL query to run. Only first column in first row will be read"));
	printf (" %s\n", "-W, --query-warning=RANGE");
	printf ("    %s\n", _("SQL query value to result in warning status (double)"));
	printf (" %s\n", "-C, --query-critical=RANGE");
	printf ("    %s\n", _("SQL query value to result in critical status (double)"));
	printf (" %s\n", "-r,  --print-query");
	printf ("    %s\n", _("Print the output of the entire query to extended plugin output."));

	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", _("If a query is specified using the -q option, it will be executed after"));
	printf (" %s\n", _("connecting to the server. The result from the query has to be numeric."));
	printf (" %s\n", _("Multiple SQL commands, separated by semicolon, are allowed but the result "));
	printf (" %s\n", _("of the last command is taken into account only. The value of the first"));
	printf (" %s\n\n", _("column in the first row is used as the check result."));

	printf (" %s\n", _("See the chapter \"Monitoring Database Activity\" of the PostgreSQL manual"));
	printf (" %s\n\n", _("for details about how to access internal statistics of the database server."));

	printf (" %s\n", _("For a list of available connection parameters which may be used with the -o"));
	printf (" %s\n", _("command line option, see the documentation for PQconnectdb() in the chapter"));
	printf (" %s\n", _("\"libpq - C Library\" of the PostgreSQL manual. For example, this may be"));
	printf (" %s\n", _("used to specify a service name in pg_service.conf to be used for additional"));
	printf (" %s\n", _("connection parameters: -o 'service=<name>' or to specify the SSL mode:"));
	printf (" %s\n\n", _("-o 'sslmode=require'."));

	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 obscure or encrypt the password."));

	printf (UT_SUPPORT);
}



void
print_usage (void)
{
	printf ("%s\n", _("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"
			"[-q <query>] [-C <critical query range>] [-W <warning query range>] [-r]\n");
}

int
do_query (PGconn *conn, char *query)
{
	PGresult *res;

	char *val_str;
	double value;

	char *endptr = NULL;

	int my_status = STATE_UNKNOWN;

	// Only used for print_query block at the end of this function
	PQprintOpt po;

	if (verbose)
		printf ("Executing SQL query \"%s\".\n", query);
	res = PQexec (conn, query);

	if (PGRES_TUPLES_OK != PQresultStatus (res)) {
		printf (_("QUERY %s - %s: %s.\n"), _("CRITICAL"), _("Error with query"),
					PQerrorMessage (conn));
		return STATE_CRITICAL;
	}

	if (PQntuples (res) < 1) {
		printf ("QUERY %s - %s.\n", _("WARNING"), _("No rows returned"));
		return STATE_WARNING;
	}

	if (PQnfields (res) < 1) {
		printf ("QUERY %s - %s.\n", _("WARNING"), _("No columns returned"));
		return STATE_WARNING;
	}

	val_str = PQgetvalue (res, 0, 0);
	if (! val_str) {
		printf ("QUERY %s - %s.\n", _("CRITICAL"), _("No data returned"));
		return STATE_CRITICAL;
	}

	value = strtod (val_str, &endptr);
	if (verbose)
		printf ("Query result: %f\n", value);

	if (endptr == val_str) {
		printf ("QUERY %s - %s: %s\n", _("CRITICAL"), _("Is not a numeric"), val_str);
		return STATE_CRITICAL;
	}
	else if ((endptr != NULL) && (*endptr != '\0')) {
		if (verbose)
			printf ("Garbage after value: %s.\n", endptr);
	}

	my_status = get_status (value, qthresholds);
	printf ("QUERY %s - ",
			(my_status == STATE_OK)
				? _("OK")
				: (my_status == STATE_WARNING)
					? _("WARNING")
					: (my_status == STATE_CRITICAL)
						? _("CRITICAL")
						: _("UNKNOWN"));
	printf (_("'%s' returned %f"), query, value);
	printf ("|query=%f;%s;%s;;\n", value,
			query_warning ? query_warning : "",
			query_critical ? query_critical : "");

	if (print_query) {
		printf("\n");
		po.header = 1;
		po.align = 1;
		po.standard = 1;
		po.html3 = 0;
		po.expanded = 0;
		po.pager = 0;
		po.fieldSep = "|";
		po.tableOpt = NULL;
		po.caption = NULL;
		po.fieldName = NULL;

		PQprint(stdout, res, &po);
	}

	return my_status;
}

