/*****************************************************************************
 *
 * Monitoring check_pgsql plugin
 *
 * License: GPL
 * Copyright (c) 1999-2024 Monitoring 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 = "1999-2024";
const char *email = "devel@monitoring-plugins.org";

#include "common.h"
#include "utils.h"
#include "utils_cmd.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
};

static int process_arguments(int /*argc*/, char ** /*argv*/);
static void print_help(void);
static bool is_pg_logname(char * /*username*/);
static int do_query(PGconn * /*conn*/, char * /*query*/);
void print_usage(void);

static char *pghost = NULL; /* host name of the backend server */
static char *pgport = NULL; /* port of the backend server */
static char *pgoptions = NULL;
static char *pgtty = NULL;
static char dbName[NAMEDATALEN] = DEFAULT_DB;
static char *pguser = NULL;
static char *pgpasswd = NULL;
static char *pgparams = NULL;
static double twarn = (double)DEFAULT_WARN;
static double tcrit = (double)DEFAULT_CRIT;
static char *pgquery = NULL;
static char *pgqueryname = NULL;
static char *query_warning = NULL;
static char *query_critical = NULL;
static thresholds *qthresholds = NULL;
static int verbose = 0;

#define OPTID_QUERYNAME -1000

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

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

	/* 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 */

	/* 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);

	char *conninfo = NULL;
	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 */
	struct timeval start_timeval;
	gettimeofday(&start_timeval, NULL);
	PGconn *conn = PQconnectdb(conninfo);
	struct timeval end_timeval;
	gettimeofday(&end_timeval, NULL);

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

	int status = STATE_UNKNOWN;
	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));

	int query_status = STATE_UNKNOWN;
	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) {
	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'},
									   {"queryname", required_argument, 0, OPTID_QUERYNAME},
									   {"query_critical", required_argument, 0, 'C'},
									   {"query_warning", required_argument, 0, 'W'},
									   {"verbose", no_argument, 0, 'v'},
									   {0, 0, 0, 0}};

	while (true) {
		int option = 0;
		int option_char = getopt_long(argc, argv, "hVt:c:w:H:P:d:l:p:a:o:q:C:W:v", longopts, &option);

		if (option_char == EOF)
			break;

		switch (option_char) {
		case '?': /* usage */
			usage5();
		case 'h': /* help */
			print_help();
			exit(STATE_UNKNOWN);
		case 'V': /* version */
			print_revision(progname, NP_VERSION);
			exit(STATE_UNKNOWN);
		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 'C': /* critical query threshold */
			query_critical = optarg;
			break;
		case 'W': /* warning query threshold */
			query_warning = optarg;
			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 (strlen(optarg) >= NAMEDATALEN) {
				usage2(_("Database name exceeds the maximum length"), optarg);
			}
			snprintf(dbName, NAMEDATALEN, "%s", 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 OPTID_QUERYNAME:
			pgqueryname = optarg;
			break;
		case 'v':
			verbose++;
			break;
		}
	}

	set_thresholds(&qthresholds, query_warning, query_critical);

	return OK;
}

/**

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>
-@@
******************************************************************************/

bool 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", _("Password (BIG SECURITY ISSUE)"));
	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", "--queryname=STRING");
	printf("    %s\n", _("A name for the query, this string is used instead of the query"));
	printf("    %s\n", _("in the long output of the plugin"));
	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(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", _("column in the first row is used as the check result. If a second column is"));
	printf(" %s\n", _("present in the result set, this is added to the plugin output with a"));
	printf(" %s\n", _("prefix of \"Extra Info:\". This information can be displayed in the system"));
	printf(" %s\n\n", _("executing the plugin."));

	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 monitoring 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>]\n");
}

int do_query(PGconn *conn, char *query) {
	if (verbose)
		printf("Executing SQL query \"%s\".\n", query);
	PGresult *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;
	}

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

	char *endptr = NULL;
	double 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;
	}

	if ((endptr != NULL) && (*endptr != '\0')) {
		if (verbose)
			printf("Garbage after value: %s.\n", endptr);
	}

	int 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"));
	if (pgqueryname) {
		printf(_("%s returned %f"), pgqueryname, value);
	} else {
		printf(_("'%s' returned %f"), query, value);
	}

	printf("|query=%f;%s;%s;;\n", value, query_warning ? query_warning : "", query_critical ? query_critical : "");
	if (PQnfields(res) > 1) {
		char *extra_info = PQgetvalue(res, 0, 1);
		if (extra_info != NULL) {
			printf("Extra Info: %s\n", extra_info);
		}
	}
	return my_status;
}