From 6bc9e518b247e85a39479a0ac6685e68c3a61b40 Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Sat, 8 Nov 2025 00:19:25 +0100
Subject: check_smtp: modern output + some tls cert helper functions

---
 plugins/check_smtp.c          | 676 ++++++++++++++++++++++++------------------
 plugins/check_smtp.d/config.h |  16 +-
 plugins/netutils.h            |  20 ++
 plugins/sslutils.c            | 132 +++++++++
 4 files changed, 550 insertions(+), 294 deletions(-)

(limited to 'plugins')

diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c
index 83ad575c..f2c7f05c 100644
--- a/plugins/check_smtp.c
+++ b/plugins/check_smtp.c
@@ -28,20 +28,24 @@
  *
  *****************************************************************************/
 
-const char *progname = "check_smtp";
-const char *copyright = "2000-2024";
-const char *email = "devel@monitoring-plugins.org";
-
 #include "common.h"
 #include "netutils.h"
+#include "output.h"
+#include "perfdata.h"
+#include "thresholds.h"
 #include "utils.h"
 #include "base64.h"
 #include "regex.h"
 
 #include <ctype.h>
+#include <string.h>
 #include "check_smtp.d/config.h"
 #include "../lib/states.h"
 
+const char *progname = "check_smtp";
+const char *copyright = "2000-2024";
+const char *email = "devel@monitoring-plugins.org";
+
 #define PROXY_PREFIX    "PROXY TCP4 0.0.0.0 0.0.0.0 25 25\r\n"
 #define SMTP_HELO       "HELO "
 #define SMTP_EHLO       "EHLO "
@@ -161,323 +165,414 @@ int main(int argc, char **argv) {
 	gettimeofday(&start_time, NULL);
 
 	int socket_descriptor = 0;
+
 	/* try to connect to the host at the given port number */
-	mp_state_enum result =
+	mp_state_enum tcp_result =
 		my_tcp_connect(config.server_address, config.server_port, &socket_descriptor);
 
-	char *error_msg = "";
+	mp_check overall = mp_check_init();
+	mp_subcheck sc_tcp_connect = mp_subcheck_init();
 	char buffer[MAX_INPUT_BUFFER];
 	bool ssl_established = false;
-	if (result == STATE_OK) { /* we connected */
-		/* If requested, send PROXY header */
-		if (config.use_proxy_prefix) {
-			if (verbose) {
-				printf("Sending header %s\n", PROXY_PREFIX);
-			}
-			my_send(config, PROXY_PREFIX, strlen(PROXY_PREFIX), socket_descriptor, ssl_established);
+
+	if (tcp_result != STATE_OK) {
+		// Connect failed
+		sc_tcp_connect = mp_set_subcheck_state(sc_tcp_connect, STATE_CRITICAL);
+		xasprintf(&sc_tcp_connect.output, "TCP connect to '%s' failed", config.server_address);
+		mp_add_subcheck_to_check(&overall, sc_tcp_connect);
+		mp_exit(overall);
+	}
+
+	/* we connected */
+	/* If requested, send PROXY header */
+	if (config.use_proxy_prefix) {
+		if (verbose) {
+			printf("Sending header %s\n", PROXY_PREFIX);
 		}
+		my_send(config, PROXY_PREFIX, strlen(PROXY_PREFIX), socket_descriptor, ssl_established);
+	}
 
 #ifdef HAVE_SSL
-		if (config.use_ssl) {
-			result = np_net_ssl_init_with_hostname(socket_descriptor,
-												   (config.use_sni ? config.server_address : NULL));
-			if (result != STATE_OK) {
-				printf(_("CRITICAL - Cannot create SSL context.\n"));
-				close(socket_descriptor);
-				np_net_ssl_cleanup();
-				exit(STATE_CRITICAL);
-			}
-			ssl_established = true;
+	if (config.use_ssl) {
+		int tls_result = np_net_ssl_init_with_hostname(
+			socket_descriptor, (config.use_sni ? config.server_address : NULL));
+
+		mp_subcheck sc_tls_connection = mp_subcheck_init();
+
+		if (tls_result != STATE_OK) {
+			close(socket_descriptor);
+			np_net_ssl_cleanup();
+
+			sc_tls_connection = mp_set_subcheck_state(sc_tls_connection, STATE_CRITICAL);
+			xasprintf(&sc_tls_connection.output, "cannot create TLS context");
+			mp_add_subcheck_to_check(&overall, sc_tls_connection);
+			mp_exit(overall);
 		}
+
+		sc_tls_connection = mp_set_subcheck_state(sc_tls_connection, STATE_OK);
+		xasprintf(&sc_tls_connection.output, "TLS context established");
+		mp_add_subcheck_to_check(&overall, sc_tls_connection);
+		ssl_established = true;
+	}
 #endif
 
-		/* watch for the SMTP connection string and */
-		/* return a WARNING status if we couldn't read any data */
-		if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) <= 0) {
-			printf(_("recv() failed\n"));
-			exit(STATE_WARNING);
+	/* watch for the SMTP connection string and */
+	/* return a WARNING status if we couldn't read any data */
+	if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) <= 0) {
+		mp_subcheck sc_read_data = mp_subcheck_init();
+		sc_read_data = mp_set_subcheck_state(sc_read_data, STATE_WARNING);
+		xasprintf(&sc_read_data.output, "recv() failed");
+		mp_add_subcheck_to_check(&overall, sc_read_data);
+		mp_exit(overall);
+	}
+
+	char *server_response = NULL;
+	/* save connect return (220 hostname ..) for later use */
+	xasprintf(&server_response, "%s", buffer);
+
+	/* send the HELO/EHLO command */
+	my_send(config, helocmd, (int)strlen(helocmd), socket_descriptor, ssl_established);
+
+	/* allow for response to helo command to reach us */
+	if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) <= 0) {
+		mp_subcheck sc_read_data = mp_subcheck_init();
+		sc_read_data = mp_set_subcheck_state(sc_read_data, STATE_WARNING);
+		xasprintf(&sc_read_data.output, "recv() failed");
+		mp_add_subcheck_to_check(&overall, sc_read_data);
+		mp_exit(overall);
+	}
+
+	bool supports_tls = false;
+	if (config.use_ehlo || config.use_lhlo) {
+		if (strstr(buffer, "250 STARTTLS") != NULL || strstr(buffer, "250-STARTTLS") != NULL) {
+			supports_tls = true;
 		}
+	}
 
-		char *server_response = NULL;
-		/* save connect return (220 hostname ..) for later use */
-		xasprintf(&server_response, "%s", buffer);
+	if (config.use_starttls && !supports_tls) {
+		smtp_quit(config, buffer, socket_descriptor, ssl_established);
 
-		/* send the HELO/EHLO command */
-		my_send(config, helocmd, (int)strlen(helocmd), socket_descriptor, ssl_established);
+		mp_subcheck sc_read_data = mp_subcheck_init();
+		sc_read_data = mp_set_subcheck_state(sc_read_data, STATE_WARNING);
+		xasprintf(&sc_read_data.output, "StartTLS not supported by server");
+		mp_add_subcheck_to_check(&overall, sc_read_data);
+		mp_exit(overall);
+	}
+
+#ifdef HAVE_SSL
+	if (config.use_starttls) {
+		/* send the STARTTLS command */
+		send(socket_descriptor, SMTP_STARTTLS, strlen(SMTP_STARTTLS), 0);
+
+		mp_subcheck sc_starttls_init = mp_subcheck_init();
+		recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
+				  ssl_established); /* wait for it */
+		if (!strstr(buffer, SMTP_EXPECT)) {
+			smtp_quit(config, buffer, socket_descriptor, ssl_established);
+
+			xasprintf(&sc_starttls_init.output, "StartTLS not supported by server");
+			sc_starttls_init = mp_set_subcheck_state(sc_starttls_init, STATE_UNKNOWN);
+			mp_add_subcheck_to_check(&overall, sc_starttls_init);
+			mp_exit(overall);
+		}
+
+		mp_state_enum starttls_result = np_net_ssl_init_with_hostname(
+			socket_descriptor, (config.use_sni ? config.server_address : NULL));
+		if (starttls_result != STATE_OK) {
+			close(socket_descriptor);
+			np_net_ssl_cleanup();
+
+			sc_starttls_init = mp_set_subcheck_state(sc_starttls_init, STATE_CRITICAL);
+			xasprintf(&sc_starttls_init.output, "failed to create StartTLS context");
+			mp_add_subcheck_to_check(&overall, sc_starttls_init);
+			mp_exit(overall);
+		}
+		sc_starttls_init = mp_set_subcheck_state(sc_starttls_init, STATE_OK);
+		xasprintf(&sc_starttls_init.output, "created StartTLS context");
+		mp_add_subcheck_to_check(&overall, sc_starttls_init);
+
+		ssl_established = true;
+
+		/*
+		 * Resend the EHLO command.
+		 *
+		 * RFC 3207 (4.2) says: ``The client MUST discard any knowledge
+		 * obtained from the server, such as the list of SMTP service
+		 * extensions, which was not obtained from the TLS negotiation
+		 * itself.  The client SHOULD send an EHLO command as the first
+		 * command after a successful TLS negotiation.''  For this
+		 * reason, some MTAs will not allow an AUTH LOGIN command before
+		 * we resent EHLO via TLS.
+		 */
+		if (my_send(config, helocmd, (int)strlen(helocmd), socket_descriptor, ssl_established) <=
+			0) {
+			my_close(socket_descriptor);
+
+			mp_subcheck sc_ehlo = mp_subcheck_init();
+			sc_ehlo = mp_set_subcheck_state(sc_ehlo, STATE_UNKNOWN);
+			xasprintf(&sc_ehlo.output, "cannot send EHLO command via StartTLS");
+			mp_add_subcheck_to_check(&overall, sc_ehlo);
+			mp_exit(overall);
+		}
+
+		if (verbose) {
+			printf(_("sent %s"), helocmd);
+		}
 
-		/* allow for response to helo command to reach us */
 		if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) <= 0) {
-			printf(_("recv() failed\n"));
-			exit(STATE_WARNING);
+			my_close(socket_descriptor);
+
+			mp_subcheck sc_ehlo = mp_subcheck_init();
+			sc_ehlo = mp_set_subcheck_state(sc_ehlo, STATE_UNKNOWN);
+			xasprintf(&sc_ehlo.output, "cannot read EHLO response via StartTLS");
+			mp_add_subcheck_to_check(&overall, sc_ehlo);
+			mp_exit(overall);
 		}
 
-		bool supports_tls = false;
-		if (config.use_ehlo || config.use_lhlo) {
-			if (strstr(buffer, "250 STARTTLS") != NULL || strstr(buffer, "250-STARTTLS") != NULL) {
-				supports_tls = true;
-			}
+		if (verbose) {
+			printf("%s", buffer);
 		}
+	}
 
-		if (config.use_starttls && !supports_tls) {
-			printf(_("WARNING - TLS not supported by server\n"));
+#	ifdef USE_OPENSSL
+	if (ssl_established) {
+		net_ssl_check_cert_result cert_check_result =
+			np_net_ssl_check_cert2(config.days_till_exp_warn, config.days_till_exp_crit);
+
+		mp_subcheck sc_cert_check = mp_subcheck_init();
+
+		switch (cert_check_result.errors) {
+		case ALL_OK: {
+			xasprintf(&sc_cert_check.output, "Certificate expiration. Remaining time %g days",
+					  cert_check_result.remaining_seconds / 86400);
+			sc_cert_check = mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
+		} break;
+		case NO_SERVER_CERTIFICATE_PRESENT: {
+			xasprintf(&sc_cert_check.output, "no server certificate present");
+			sc_cert_check = mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
+		} break;
+		case UNABLE_TO_RETRIEVE_CERTIFICATE_SUBJECT: {
+			xasprintf(&sc_cert_check.output, "can not retrieve certificate subject");
+			sc_cert_check = mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
+		} break;
+		case WRONG_TIME_FORMAT_IN_CERTIFICATE: {
+			xasprintf(&sc_cert_check.output, "wrong time format in certificate");
+			sc_cert_check = mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
+		} break;
+		};
+
+		mp_add_subcheck_to_check(&overall, sc_cert_check);
+
+		if (config.check_cert) {
 			smtp_quit(config, buffer, socket_descriptor, ssl_established);
-			exit(STATE_WARNING);
+			my_close(socket_descriptor);
+			mp_exit(overall);
 		}
+	}
+#	endif /* USE_OPENSSL */
 
-#ifdef HAVE_SSL
-		if (config.use_starttls) {
-			/* send the STARTTLS command */
-			send(socket_descriptor, SMTP_STARTTLS, strlen(SMTP_STARTTLS), 0);
-
-			recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
-					  ssl_established); /* wait for it */
-			if (!strstr(buffer, SMTP_EXPECT)) {
-				printf(_("Server does not support STARTTLS\n"));
-				smtp_quit(config, buffer, socket_descriptor, ssl_established);
-				exit(STATE_UNKNOWN);
-			}
+#endif
 
-			result = np_net_ssl_init_with_hostname(socket_descriptor,
-												   (config.use_sni ? config.server_address : NULL));
-			if (result != STATE_OK) {
-				printf(_("CRITICAL - Cannot create SSL context.\n"));
-				close(socket_descriptor);
-				np_net_ssl_cleanup();
-				exit(STATE_CRITICAL);
-			}
+	if (verbose) {
+		printf("%s", buffer);
+	}
 
-			ssl_established = true;
-
-			/*
-			 * Resend the EHLO command.
-			 *
-			 * RFC 3207 (4.2) says: ``The client MUST discard any knowledge
-			 * obtained from the server, such as the list of SMTP service
-			 * extensions, which was not obtained from the TLS negotiation
-			 * itself.  The client SHOULD send an EHLO command as the first
-			 * command after a successful TLS negotiation.''  For this
-			 * reason, some MTAs will not allow an AUTH LOGIN command before
-			 * we resent EHLO via TLS.
-			 */
-			if (my_send(config, helocmd, strlen(helocmd), socket_descriptor, ssl_established) <=
-				0) {
-				printf("%s\n", _("SMTP UNKNOWN - Cannot send EHLO command via TLS."));
-				my_close(socket_descriptor);
-				exit(STATE_UNKNOWN);
-			}
+	/* save buffer for later use */
+	xasprintf(&server_response, "%s%s", server_response, buffer);
+	/* strip the buffer of carriage returns */
+	strip(server_response);
 
-			if (verbose) {
-				printf(_("sent %s"), helocmd);
-			}
+	/* make sure we find the droids we are looking for */
+	mp_subcheck sc_expect_response = mp_subcheck_init();
 
-			if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) <=
-				0) {
-				printf("%s\n", _("SMTP UNKNOWN - Cannot read EHLO response via TLS."));
-				my_close(socket_descriptor);
-				exit(STATE_UNKNOWN);
-			}
+	if (!strstr(server_response, config.server_expect)) {
+		sc_expect_response = mp_set_subcheck_state(sc_expect_response, STATE_WARNING);
+		if (config.server_port == SMTP_PORT) {
+			xasprintf(&sc_expect_response.output, _("invalid SMTP response received from host: %s"),
+					  server_response);
+		} else {
+			xasprintf(&sc_expect_response.output,
+					  _("invalid SMTP response received from host on port %d: %s"),
+					  config.server_port, server_response);
+		}
+		exit(STATE_WARNING);
+	} else {
+		xasprintf(&sc_expect_response.output, "received valid SMTP response '%s' from host: '%s'",
+				  config.server_expect, server_response);
+		sc_expect_response = mp_set_subcheck_state(sc_expect_response, STATE_OK);
+	}
 
-			if (verbose) {
-				printf("%s", buffer);
-			}
+	mp_add_subcheck_to_check(&overall, sc_expect_response);
 
-#	ifdef USE_OPENSSL
-			if (config.check_cert) {
-				result =
-					np_net_ssl_check_cert(config.days_till_exp_warn, config.days_till_exp_crit);
-				smtp_quit(config, buffer, socket_descriptor, ssl_established);
-				my_close(socket_descriptor);
-				exit(result);
-			}
-#	endif /* USE_OPENSSL */
+	if (config.send_mail_from) {
+		my_send(config, cmd_str, (int)strlen(cmd_str), socket_descriptor, ssl_established);
+		if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) >= 1 &&
+			verbose) {
+			printf("%s", buffer);
 		}
-#endif
+	}
 
-		if (verbose) {
+	size_t counter = 0;
+	while (counter < config.ncommands) {
+		xasprintf(&cmd_str, "%s%s", config.commands[counter], "\r\n");
+		my_send(config, cmd_str, (int)strlen(cmd_str), socket_descriptor, ssl_established);
+		if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) >= 1 &&
+			verbose) {
 			printf("%s", buffer);
 		}
 
-		/* save buffer for later use */
-		xasprintf(&server_response, "%s%s", server_response, buffer);
-		/* strip the buffer of carriage returns */
-		strip(server_response);
+		strip(buffer);
 
-		/* make sure we find the droids we are looking for */
-		if (!strstr(server_response, config.server_expect)) {
-			if (config.server_port == SMTP_PORT) {
-				printf(_("Invalid SMTP response received from host: %s\n"), server_response);
-			} else {
-				printf(_("Invalid SMTP response received from host on port %d: %s\n"),
-					   config.server_port, server_response);
+		if (counter < config.nresponses) {
+			int cflags = REG_EXTENDED | REG_NOSUB | REG_NEWLINE;
+			regex_t preg;
+			int errcode = regcomp(&preg, config.responses[counter], cflags);
+			char errbuf[MAX_INPUT_BUFFER];
+			if (errcode != 0) {
+				regerror(errcode, &preg, errbuf, MAX_INPUT_BUFFER);
+				printf(_("Could Not Compile Regular Expression"));
+				exit(STATE_UNKNOWN);
 			}
-			exit(STATE_WARNING);
-		}
 
-		if (config.send_mail_from) {
-			my_send(config, cmd_str, (int)strlen(cmd_str), socket_descriptor, ssl_established);
-			if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) >=
-					1 &&
-				verbose) {
-				printf("%s", buffer);
+			regmatch_t pmatch[10];
+			int eflags = 0;
+			int excode = regexec(&preg, buffer, 10, pmatch, eflags);
+			mp_subcheck sc_expected_responses = mp_subcheck_init();
+			if (excode == 0) {
+				xasprintf(&sc_expected_responses.output, "valid response '%s' to command '%s'",
+						  buffer, config.commands[counter]);
+				sc_expected_responses = mp_set_subcheck_state(sc_expected_responses, STATE_OK);
+			} else if (excode == REG_NOMATCH) {
+				sc_expected_responses = mp_set_subcheck_state(sc_expected_responses, STATE_WARNING);
+				xasprintf(&sc_expected_responses.output, "invalid response '%s' to command '%s'",
+						  buffer, config.commands[counter]);
+			} else {
+				regerror(excode, &preg, errbuf, MAX_INPUT_BUFFER);
+				xasprintf(&sc_expected_responses.output, "regexec execute error: %s", errbuf);
+				sc_expected_responses = mp_set_subcheck_state(sc_expected_responses, STATE_UNKNOWN);
 			}
 		}
+		counter++;
+	}
 
-		int counter = 0;
-		while (counter < config.ncommands) {
-			xasprintf(&cmd_str, "%s%s", config.commands[counter], "\r\n");
-			my_send(config, cmd_str, (int)strlen(cmd_str), socket_descriptor, ssl_established);
-			if (recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor, ssl_established) >=
-					1 &&
-				verbose) {
-				printf("%s", buffer);
-			}
-			strip(buffer);
-			if (counter < config.nresponses) {
-				int cflags = REG_EXTENDED | REG_NOSUB | REG_NEWLINE;
-				regex_t preg;
-				int errcode = regcomp(&preg, config.responses[counter], cflags);
-				char errbuf[MAX_INPUT_BUFFER];
-				if (errcode != 0) {
-					regerror(errcode, &preg, errbuf, MAX_INPUT_BUFFER);
-					printf(_("Could Not Compile Regular Expression"));
-					exit(STATE_UNKNOWN);
+	if (config.authtype != NULL) {
+		mp_subcheck sc_auth = mp_subcheck_init();
+
+		if (strcmp(config.authtype, "LOGIN") == 0) {
+			char *abuf;
+			int ret;
+			do {
+				/* send AUTH LOGIN */
+				my_send(config, SMTP_AUTH_LOGIN, strlen(SMTP_AUTH_LOGIN), socket_descriptor,
+						ssl_established);
+
+				if (verbose) {
+					printf(_("sent %s\n"), "AUTH LOGIN");
 				}
 
-				regmatch_t pmatch[10];
-				int eflags = 0;
-				int excode = regexec(&preg, buffer, 10, pmatch, eflags);
-				if (excode == 0) {
-					result = STATE_OK;
-				} else if (excode == REG_NOMATCH) {
-					result = STATE_WARNING;
-					printf(_("SMTP %s - Invalid response '%s' to command '%s'\n"),
-						   state_text(result), buffer, config.commands[counter]);
-				} else {
-					regerror(excode, &preg, errbuf, MAX_INPUT_BUFFER);
-					printf(_("Execute Error: %s\n"), errbuf);
-					result = STATE_UNKNOWN;
+				if ((ret = recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
+									 ssl_established)) <= 0) {
+					xasprintf(&sc_auth.output, _("recv() failed after AUTH LOGIN"));
+					sc_auth = mp_set_subcheck_state(sc_auth, STATE_WARNING);
+					break;
 				}
-			}
-			counter++;
-		}
 
-		if (config.authtype != NULL) {
-			if (strcmp(config.authtype, "LOGIN") == 0) {
-				char *abuf;
-				int ret;
-				do {
-					if (config.authuser == NULL) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("no authuser specified, "));
-						break;
-					}
-					if (config.authpass == NULL) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("no authpass specified, "));
-						break;
-					}
-
-					/* send AUTH LOGIN */
-					my_send(config, SMTP_AUTH_LOGIN, strlen(SMTP_AUTH_LOGIN), socket_descriptor,
-							ssl_established);
-					if (verbose) {
-						printf(_("sent %s\n"), "AUTH LOGIN");
-					}
-
-					if ((ret = recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
-										 ssl_established)) <= 0) {
-						xasprintf(&error_msg, _("recv() failed after AUTH LOGIN, "));
-						result = STATE_WARNING;
-						break;
-					}
-					if (verbose) {
-						printf(_("received %s\n"), buffer);
-					}
-
-					if (strncmp(buffer, "334", 3) != 0) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("invalid response received after AUTH LOGIN, "));
-						break;
-					}
-
-					/* encode authuser with base64 */
-					base64_encode_alloc(config.authuser, strlen(config.authuser), &abuf);
-					xasprintf(&abuf, "%s\r\n", abuf);
-					my_send(config, abuf, (int)strlen(abuf), socket_descriptor, ssl_established);
-					if (verbose) {
-						printf(_("sent %s\n"), abuf);
-					}
-
-					if ((ret = recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
-										 ssl_established)) <= 0) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("recv() failed after sending authuser, "));
-						break;
-					}
-					if (verbose) {
-						printf(_("received %s\n"), buffer);
-					}
-					if (strncmp(buffer, "334", 3) != 0) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("invalid response received after authuser, "));
-						break;
-					}
-					/* encode authpass with base64 */
-					base64_encode_alloc(config.authpass, strlen(config.authpass), &abuf);
-					xasprintf(&abuf, "%s\r\n", abuf);
-					my_send(config, abuf, (int)strlen(abuf), socket_descriptor, ssl_established);
-					if (verbose) {
-						printf(_("sent %s\n"), abuf);
-					}
-					if ((ret = recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
-										 ssl_established)) <= 0) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("recv() failed after sending authpass, "));
-						break;
-					}
-					if (verbose) {
-						printf(_("received %s\n"), buffer);
-					}
-					if (strncmp(buffer, "235", 3) != 0) {
-						result = STATE_CRITICAL;
-						xasprintf(&error_msg, _("invalid response received after authpass, "));
-						break;
-					}
+				if (verbose) {
+					printf(_("received %s\n"), buffer);
+				}
+
+				if (strncmp(buffer, "334", 3) != 0) {
+					xasprintf(&sc_auth.output, "invalid response received after AUTH LOGIN");
+					sc_auth = mp_set_subcheck_state(sc_auth, STATE_CRITICAL);
 					break;
-				} while (false);
-			} else {
-				result = STATE_CRITICAL;
-				xasprintf(&error_msg, _("only authtype LOGIN is supported, "));
-			}
-		}
+				}
 
-		/* tell the server we're done */
-		smtp_quit(config, buffer, socket_descriptor, ssl_established);
+				/* encode authuser with base64 */
+				base64_encode_alloc(config.authuser, strlen(config.authuser), &abuf);
+				xasprintf(&abuf, "%s\r\n", abuf);
+				my_send(config, abuf, (int)strlen(abuf), socket_descriptor, ssl_established);
+				if (verbose) {
+					printf(_("sent %s\n"), abuf);
+				}
 
-		/* finally close the connection */
-		close(socket_descriptor);
+				if ((ret = recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
+									 ssl_established)) <= 0) {
+					xasprintf(&sc_auth.output, "recv() failed after sending authuser");
+					sc_auth = mp_set_subcheck_state(sc_auth, STATE_CRITICAL);
+					break;
+				}
+
+				if (verbose) {
+					printf(_("received %s\n"), buffer);
+				}
+
+				if (strncmp(buffer, "334", 3) != 0) {
+					xasprintf(&sc_auth.output, "invalid response received after authuser");
+					sc_auth = mp_set_subcheck_state(sc_auth, STATE_CRITICAL);
+					break;
+				}
+
+				/* encode authpass with base64 */
+				base64_encode_alloc(config.authpass, strlen(config.authpass), &abuf);
+				xasprintf(&abuf, "%s\r\n", abuf);
+				my_send(config, abuf, (int)strlen(abuf), socket_descriptor, ssl_established);
+
+				if (verbose) {
+					printf(_("sent %s\n"), abuf);
+				}
+
+				if ((ret = recvlines(config, buffer, MAX_INPUT_BUFFER, socket_descriptor,
+									 ssl_established)) <= 0) {
+					xasprintf(&sc_auth.output, "recv() failed after sending authpass");
+					sc_auth = mp_set_subcheck_state(sc_auth, STATE_CRITICAL);
+					break;
+				}
+
+				if (verbose) {
+					printf(_("received %s\n"), buffer);
+				}
+
+				if (strncmp(buffer, "235", 3) != 0) {
+					xasprintf(&sc_auth.output, "invalid response received after authpass");
+					sc_auth = mp_set_subcheck_state(sc_auth, STATE_CRITICAL);
+					break;
+				}
+				break;
+			} while (false);
+		} else {
+			sc_auth = mp_set_subcheck_state(sc_auth, STATE_CRITICAL);
+			xasprintf(&sc_auth.output, "only authtype LOGIN is supported");
+		}
+
+		mp_add_subcheck_to_check(&overall, sc_auth);
 	}
 
+	/* tell the server we're done */
+	smtp_quit(config, buffer, socket_descriptor, ssl_established);
+
+	/* finally close the connection */
+	close(socket_descriptor);
+
 	/* reset the alarm */
 	alarm(0);
 
 	long microsec = deltime(start_time);
 	double elapsed_time = (double)microsec / 1.0e6;
 
-	if (result == STATE_OK) {
-		if (config.check_critical_time && elapsed_time > config.critical_time) {
-			result = STATE_CRITICAL;
-		} else if (config.check_warning_time && elapsed_time > config.warning_time) {
-			result = STATE_WARNING;
-		}
-	}
+	mp_perfdata pd_elapsed_time = perfdata_init();
+	pd_elapsed_time = mp_set_pd_value(pd_elapsed_time, elapsed_time);
+	pd_elapsed_time.label = "time";
+	pd_elapsed_time.uom = "s";
 
-	printf(_("SMTP %s - %s%.3f sec. response time%s%s|%s\n"), state_text(result), error_msg,
-		   elapsed_time, verbose ? ", " : "", verbose ? buffer : "",
-		   fperfdata("time", elapsed_time, "s", config.check_warning_time, config.warning_time,
-					 config.check_critical_time, config.critical_time, true, 0, false, 0));
+	pd_elapsed_time = mp_pd_set_thresholds(pd_elapsed_time, config.connection_time);
 
-	exit(result);
+	mp_subcheck sc_connection_time = mp_subcheck_init();
+	xasprintf(&sc_connection_time.output, "connection time: %.3gs", elapsed_time);
+	sc_connection_time =
+		mp_set_subcheck_state(sc_connection_time, mp_get_pd_status(pd_elapsed_time));
+	mp_add_subcheck_to_check(&overall, sc_connection_time);
+
+	mp_exit(overall);
 }
 
 /* process command-line arguments */
@@ -535,8 +630,8 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 		}
 	}
 
-	int command_size = 0;
-	int response_size = 0;
+	unsigned long command_size = 0;
+	unsigned long response_size = 0;
 	bool implicit_tls = false;
 	int server_port_option = 0;
 	while (true) {
@@ -591,7 +686,7 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 				result.config.commands =
 					realloc(result.config.commands, sizeof(char *) * command_size);
 				if (result.config.commands == NULL) {
-					die(STATE_UNKNOWN, _("Could not realloc() units [%d]\n"),
+					die(STATE_UNKNOWN, _("Could not realloc() units [%lu]\n"),
 						result.config.ncommands);
 				}
 			}
@@ -605,7 +700,7 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 				result.config.responses =
 					realloc(result.config.responses, sizeof(char *) * response_size);
 				if (result.config.responses == NULL) {
-					die(STATE_UNKNOWN, _("Could not realloc() units [%d]\n"),
+					die(STATE_UNKNOWN, _("Could not realloc() units [%lu]\n"),
 						result.config.nresponses);
 				}
 			}
@@ -613,22 +708,22 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 			strncpy(result.config.responses[result.config.nresponses], optarg, 255);
 			result.config.nresponses++;
 			break;
-		case 'c': /* critical time threshold */
-			if (!is_nonnegative(optarg)) {
-				usage4(_("Critical time must be a positive"));
-			} else {
-				result.config.critical_time = strtod(optarg, NULL);
-				result.config.check_critical_time = true;
+		case 'c': /* critical time threshold */ {
+			mp_range_parsed tmp = mp_parse_range_string(optarg);
+			if (tmp.error != MP_PARSING_SUCCES) {
+				die(STATE_UNKNOWN, "failed to parse critical time threshold");
 			}
-			break;
-		case 'w': /* warning time threshold */
-			if (!is_nonnegative(optarg)) {
-				usage4(_("Warning time must be a positive"));
-			} else {
-				result.config.warning_time = strtod(optarg, NULL);
-				result.config.check_warning_time = true;
+			result.config.connection_time =
+				mp_thresholds_set_warn(result.config.connection_time, tmp.range);
+		} break;
+		case 'w': /* warning time threshold */ {
+			mp_range_parsed tmp = mp_parse_range_string(optarg);
+			if (tmp.error != MP_PARSING_SUCCES) {
+				die(STATE_UNKNOWN, "failed to parse warning time threshold");
 			}
-			break;
+			result.config.connection_time =
+				mp_thresholds_set_crit(result.config.connection_time, tmp.range);
+		} break;
 		case 'v': /* verbose */
 			verbose++;
 			break;
@@ -742,6 +837,19 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 		result.config.server_port = server_port_option;
 	}
 
+	if (result.config.authtype) {
+		if (strcmp(result.config.authtype, "LOGIN") == 0) {
+			if (result.config.authuser == NULL) {
+				usage4("no authuser specified");
+			}
+			if (result.config.authpass == NULL) {
+				usage4("no authpass specified");
+			}
+		} else {
+			usage4("only authtype LOGIN is supported");
+		}
+	}
+
 	return result;
 }
 
@@ -791,7 +899,7 @@ char *smtp_quit(check_smtp_config config, char buffer[MAX_INPUT_BUFFER], int soc
 int recvline(char *buf, size_t bufsize, check_smtp_config config, int socket_descriptor,
 			 bool ssl_established) {
 	int result;
-	int counter;
+	size_t counter;
 
 	for (counter = result = 0; counter < bufsize - 1; counter++) {
 		if ((result = my_recv(config, &buf[counter], 1, socket_descriptor, ssl_established)) != 1) {
@@ -799,7 +907,7 @@ int recvline(char *buf, size_t bufsize, check_smtp_config config, int socket_des
 		}
 		if (buf[counter] == '\n') {
 			buf[++counter] = '\0';
-			return counter;
+			return (int)counter;
 		}
 	}
 	return (result == 1 || counter == 0) ? -2 : result; /* -2 if out of space */
diff --git a/plugins/check_smtp.d/config.h b/plugins/check_smtp.d/config.h
index 0a6511ef..bc433093 100644
--- a/plugins/check_smtp.d/config.h
+++ b/plugins/check_smtp.d/config.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "../../config.h"
+#include "thresholds.h"
 #include <stddef.h>
 #include <string.h>
 
@@ -18,20 +19,18 @@ typedef struct {
 	char *server_expect;
 	bool ignore_send_quit_failure;
 
-	double warning_time;
-	bool check_warning_time;
-	double critical_time;
-	bool check_critical_time;
+	mp_thresholds connection_time;
+
 	bool use_ehlo;
 	bool use_lhlo;
 
 	char *from_arg;
 	bool send_mail_from;
 
-	int ncommands;
+	unsigned long ncommands;
 	char **commands;
 
-	int nresponses;
+	unsigned long nresponses;
 	char **responses;
 
 	char *authtype;
@@ -58,10 +57,7 @@ check_smtp_config check_smtp_config_init() {
 		.server_expect = SMTP_EXPECT,
 		.ignore_send_quit_failure = false,
 
-		.warning_time = 0,
-		.check_warning_time = false,
-		.critical_time = 0,
-		.check_critical_time = false,
+		.connection_time = mp_thresholds_init(),
 		.use_ehlo = false,
 		.use_lhlo = false,
 
diff --git a/plugins/netutils.h b/plugins/netutils.h
index c4461113..dbd22398 100644
--- a/plugins/netutils.h
+++ b/plugins/netutils.h
@@ -114,6 +114,26 @@ int np_net_ssl_init_with_hostname_version_and_cert(int socket, char *host_name,
 void np_net_ssl_cleanup(void);
 int np_net_ssl_write(const void *buf, int num);
 int np_net_ssl_read(void *buf, int num);
+
+typedef enum {
+	ALL_OK,
+	NO_SERVER_CERTIFICATE_PRESENT,
+	UNABLE_TO_RETRIEVE_CERTIFICATE_SUBJECT,
+	WRONG_TIME_FORMAT_IN_CERTIFICATE,
+} retrieve_expiration_date_errors;
+
+typedef struct {
+	double remaining_seconds;
+	retrieve_expiration_date_errors errors;
+} retrieve_expiration_time_result;
+
+typedef struct {
+	mp_state_enum result_state;
+	double remaining_seconds;
+	retrieve_expiration_date_errors errors;
+} net_ssl_check_cert_result;
+net_ssl_check_cert_result np_net_ssl_check_cert2(int days_till_exp_warn, int days_till_exp_crit);
+
 mp_state_enum np_net_ssl_check_cert(int days_till_exp_warn, int days_till_exp_crit);
 mp_subcheck mp_net_ssl_check_cert(int days_till_exp_warn, int days_till_exp_crit);
 #endif /* HAVE_SSL */
diff --git a/plugins/sslutils.c b/plugins/sslutils.c
index 0e6d7525..c1d15534 100644
--- a/plugins/sslutils.c
+++ b/plugins/sslutils.c
@@ -312,6 +312,138 @@ mp_state_enum np_net_ssl_check_certificate(X509 *certificate, int days_till_exp_
 #	endif /* USE_OPENSSL */
 }
 
+retrieve_expiration_time_result np_net_ssl_get_cert_expiration(X509 *certificate) {
+#	ifdef USE_OPENSSL
+	retrieve_expiration_time_result result = {
+		.errors = ALL_OK,
+		.remaining_seconds = {},
+	};
+
+	if (!certificate) {
+		// printf("%s\n", _("CRITICAL - No server certificate present to inspect."));
+		result.errors = NO_SERVER_CERTIFICATE_PRESENT;
+		return result;
+	}
+
+	/* Extract CN from certificate subject */
+	X509_NAME *subj = X509_get_subject_name(certificate);
+
+	if (!subj) {
+		// printf("%s\n", _("CRITICAL - Cannot retrieve certificate subject."));
+		result.errors = UNABLE_TO_RETRIEVE_CERTIFICATE_SUBJECT;
+		return result;
+	}
+
+	char cn[MAX_CN_LENGTH] = "";
+	int cnlen = X509_NAME_get_text_by_NID(subj, NID_commonName, cn, sizeof(cn));
+	if (cnlen == -1) {
+		strcpy(cn, _("Unknown CN"));
+	}
+
+	/* Retrieve timestamp of certificate */
+	ASN1_STRING *expiration_timestamp = X509_get_notAfter(certificate);
+
+	int offset = 0;
+	struct tm stamp = {};
+	/* Generate tm structure to process timestamp */
+	if (expiration_timestamp->type == V_ASN1_UTCTIME) {
+		if (expiration_timestamp->length < 10) {
+			result.errors = WRONG_TIME_FORMAT_IN_CERTIFICATE;
+			return result;
+		}
+
+		stamp.tm_year =
+			(expiration_timestamp->data[0] - '0') * 10 + (expiration_timestamp->data[1] - '0');
+		if (stamp.tm_year < 50) {
+			stamp.tm_year += 100;
+		}
+		offset = 0;
+	} else {
+		if (expiration_timestamp->length < 12) {
+			result.errors = WRONG_TIME_FORMAT_IN_CERTIFICATE;
+			return result;
+		}
+
+		stamp.tm_year = (expiration_timestamp->data[0] - '0') * 1000 +
+						(expiration_timestamp->data[1] - '0') * 100 +
+						(expiration_timestamp->data[2] - '0') * 10 +
+						(expiration_timestamp->data[3] - '0');
+		stamp.tm_year -= 1900;
+		offset = 2;
+	}
+	stamp.tm_mon = (expiration_timestamp->data[2 + offset] - '0') * 10 +
+				   (expiration_timestamp->data[3 + offset] - '0') - 1;
+	stamp.tm_mday = (expiration_timestamp->data[4 + offset] - '0') * 10 +
+					(expiration_timestamp->data[5 + offset] - '0');
+	stamp.tm_hour = (expiration_timestamp->data[6 + offset] - '0') * 10 +
+					(expiration_timestamp->data[7 + offset] - '0');
+	stamp.tm_min = (expiration_timestamp->data[8 + offset] - '0') * 10 +
+				   (expiration_timestamp->data[9 + offset] - '0');
+	stamp.tm_sec = (expiration_timestamp->data[10 + offset] - '0') * 10 +
+				   (expiration_timestamp->data[11 + offset] - '0');
+	stamp.tm_isdst = -1;
+
+	time_t tm_t = timegm(&stamp);
+	double time_left = difftime(tm_t, time(NULL));
+	result.remaining_seconds = time_left;
+
+	char *timezone = getenv("TZ");
+	setenv("TZ", "GMT", 1);
+	tzset();
+
+	char timestamp[50] = "";
+	strftime(timestamp, 50, "%c %z", localtime(&tm_t));
+	if (timezone) {
+		setenv("TZ", timezone, 1);
+	} else {
+		unsetenv("TZ");
+	}
+
+	tzset();
+
+	X509_free(certificate);
+
+	return result;
+#	else  /* ifndef USE_OPENSSL */
+	printf("%s\n", _("WARNING - Plugin does not support checking certificates."));
+	return STATE_WARNING;
+#	endif /* USE_OPENSSL */
+}
+
+net_ssl_check_cert_result np_net_ssl_check_cert2(int days_till_exp_warn, int days_till_exp_crit) {
+#	ifdef USE_OPENSSL
+	X509 *certificate = NULL;
+	certificate = SSL_get_peer_certificate(s);
+
+	retrieve_expiration_time_result expiration_date = np_net_ssl_get_cert_expiration(certificate);
+
+	net_ssl_check_cert_result result = {
+		.result_state = STATE_UNKNOWN,
+		.remaining_seconds = expiration_date.remaining_seconds,
+		.errors = expiration_date.errors,
+	};
+
+	if (expiration_date.errors == ALL_OK) {
+		// got a valid expiration date
+		unsigned int remaining_days = result.remaining_seconds / 86400;
+
+		if (remaining_days < days_till_exp_crit) {
+			result.result_state = STATE_CRITICAL;
+		} else if (remaining_days < days_till_exp_warn) {
+			result.result_state = STATE_WARNING;
+		} else {
+			result.result_state = STATE_OK;
+		}
+	}
+
+	return result;
+
+#	else  /* ifndef USE_OPENSSL */
+	printf("%s\n", _("WARNING - Plugin does not support checking certificates."));
+	return STATE_WARNING;
+#	endif /* USE_OPENSSL */
+}
+
 mp_state_enum np_net_ssl_check_cert(int days_till_exp_warn, int days_till_exp_crit) {
 #	ifdef USE_OPENSSL
 	X509 *certificate = NULL;
-- 
cgit v1.2.3-74-g34f1


From e0b127312797cd4619886dc6df57411a77fe2d33 Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Sat, 8 Nov 2025 00:46:37 +0100
Subject: check_smtp: adapt tests

---
 plugins/t/check_smtp.t | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

(limited to 'plugins')

diff --git a/plugins/t/check_smtp.t b/plugins/t/check_smtp.t
index 73b4a1fd..6c8601d3 100644
--- a/plugins/t/check_smtp.t
+++ b/plugins/t/check_smtp.t
@@ -5,6 +5,7 @@
 #
 
 use strict;
+use warnings;
 use Test::More;
 use NPTest;
 
@@ -42,12 +43,11 @@ SKIP: {
 
 	TODO: {
 		local $TODO = "Output is over two lines";
-		like ( $res->output, qr/^SMTP WARNING/, "Correct error message" );
 	}
 
 	$res = NPTest->testCmd( "./check_smtp -H $host_tcp_smtp --ssl -p 25" );
 	is ($res->return_code, 2, "Check rc of connecting to $host_tcp_smtp with TLS on standard SMTP port" );
-	like ($res->output, qr/^CRITICAL - Cannot make SSL connection\./, "Check output of connecting to $host_tcp_smtp with TLS on standard SMTP port");
+	like ($res->output, qr/^cannot create TLS context\./, "Check output of connecting to $host_tcp_smtp with TLS on standard SMTP port");
 }
 
 SKIP: {
@@ -68,7 +68,6 @@ SKIP: {
 	skip "No SMTP server with TLS defined", 1 unless $host_tcp_smtp_tls;
 	$res = NPTest->testCmd( "./check_smtp -H $host_tcp_smtp_tls --ssl" );
 	is ($res->return_code, 0, "Check rc of connecting to $host_tcp_smtp_tls with TLS" );
-	like ($res->output, qr/^SMTP OK - /, "Check output of connecting to $host_tcp_smtp_tls with TLS" );
 
 	my $unused_port = 4465;
 	$res = NPTest->testCmd( "./check_smtp -H $host_tcp_smtp_tls -p $unused_port --ssl" );
-- 
cgit v1.2.3-74-g34f1


From 034d4ee15840550dac4a57b41f5b60732ca1df6b Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Sat, 8 Nov 2025 00:59:46 +0100
Subject: Fix initialisation on old compilers

---
 plugins/sslutils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'plugins')

diff --git a/plugins/sslutils.c b/plugins/sslutils.c
index c1d15534..c58a35ab 100644
--- a/plugins/sslutils.c
+++ b/plugins/sslutils.c
@@ -316,7 +316,7 @@ retrieve_expiration_time_result np_net_ssl_get_cert_expiration(X509 *certificate
 #	ifdef USE_OPENSSL
 	retrieve_expiration_time_result result = {
 		.errors = ALL_OK,
-		.remaining_seconds = {},
+		.remaining_seconds = 0,
 	};
 
 	if (!certificate) {
-- 
cgit v1.2.3-74-g34f1


From 4442ea917b9b3a7bc4fe4b980bbfc70b533a6010 Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Sat, 8 Nov 2025 01:15:54 +0100
Subject: small test correction

---
 plugins/t/check_smtp.t | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'plugins')

diff --git a/plugins/t/check_smtp.t b/plugins/t/check_smtp.t
index 6c8601d3..c2f53c3d 100644
--- a/plugins/t/check_smtp.t
+++ b/plugins/t/check_smtp.t
@@ -25,7 +25,7 @@ my $hostname_invalid   = getTestParameter( "NP_HOSTNAME_INVALID",
                                            "An invalid (not known to DNS) hostname", "nosuchhost" );
 my $res;
 
-plan tests => 15;
+plan tests => 13;
 
 SKIP: {
 	skip "No SMTP server defined", 4 unless $host_tcp_smtp;
@@ -47,7 +47,7 @@ SKIP: {
 
 	$res = NPTest->testCmd( "./check_smtp -H $host_tcp_smtp --ssl -p 25" );
 	is ($res->return_code, 2, "Check rc of connecting to $host_tcp_smtp with TLS on standard SMTP port" );
-	like ($res->output, qr/^cannot create TLS context\./, "Check output of connecting to $host_tcp_smtp with TLS on standard SMTP port");
+	like ($res->output, qr/cannot create TLS context/, "Check output of connecting to $host_tcp_smtp with TLS on standard SMTP port");
 }
 
 SKIP: {
-- 
cgit v1.2.3-74-g34f1


From 62035adf6c8199eba54755f23e8affe97e645300 Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Sun, 9 Nov 2025 11:32:43 +0100
Subject: check_smtp: implement output format cli parameter

---
 plugins/check_smtp.c          | 22 +++++++++++++++++++++-
 plugins/check_smtp.d/config.h |  6 ++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

(limited to 'plugins')

diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c
index f2c7f05c..cb92421c 100644
--- a/plugins/check_smtp.c
+++ b/plugins/check_smtp.c
@@ -115,6 +115,10 @@ int main(int argc, char **argv) {
 
 	const check_smtp_config config = tmp_config.config;
 
+	if (config.output_format_is_set) {
+		mp_set_format(config.output_format);
+	}
+
 	/* If localhostname not set on command line, use gethostname to set */
 	char *localhostname = config.localhostname;
 	if (!localhostname) {
@@ -578,7 +582,8 @@ int main(int argc, char **argv) {
 /* process command-line arguments */
 check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 	enum {
-		SNI_OPTION = CHAR_MAX + 1
+		SNI_OPTION = CHAR_MAX + 1,
+		output_format_index,
 	};
 
 	int option = 0;
@@ -608,6 +613,7 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 									   {"certificate", required_argument, 0, 'D'},
 									   {"ignore-quit-failure", no_argument, 0, 'q'},
 									   {"proxy", no_argument, 0, 'r'},
+									   {"output-format", required_argument, 0, output_format_index},
 									   {0, 0, 0, 0}};
 
 	check_smtp_config_wrapper result = {
@@ -809,6 +815,18 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 			exit(STATE_UNKNOWN);
 		case '?': /* help */
 			usage5();
+		case output_format_index: {
+			parsed_output_format parser = mp_parse_output_format(optarg);
+			if (!parser.parsing_success) {
+				// TODO List all available formats here, maybe add anothoer usage function
+				printf("Invalid output format: %s\n", optarg);
+				exit(STATE_UNKNOWN);
+			}
+
+			result.config.output_format_is_set = true;
+			result.config.output_format = parser.output_format;
+			break;
+		}
 		}
 	}
 
@@ -1015,6 +1033,8 @@ void print_help(void) {
 
 	printf(UT_CONN_TIMEOUT, DEFAULT_SOCKET_TIMEOUT);
 
+	printf(UT_OUTPUT_FORMAT);
+
 	printf(UT_VERBOSE);
 
 	printf("\n");
diff --git a/plugins/check_smtp.d/config.h b/plugins/check_smtp.d/config.h
index bc433093..11d7fe56 100644
--- a/plugins/check_smtp.d/config.h
+++ b/plugins/check_smtp.d/config.h
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "../../config.h"
+#include "output.h"
 #include "thresholds.h"
 #include <stddef.h>
 #include <string.h>
@@ -46,6 +47,9 @@ typedef struct {
 	bool use_starttls;
 	bool use_sni;
 #endif
+
+	bool output_format_is_set;
+	mp_output_format output_format;
 } check_smtp_config;
 
 check_smtp_config check_smtp_config_init() {
@@ -83,6 +87,8 @@ check_smtp_config check_smtp_config_init() {
 		.use_starttls = false,
 		.use_sni = false,
 #endif
+
+		.output_format_is_set = false,
 	};
 	return tmp;
 }
-- 
cgit v1.2.3-74-g34f1


From bc2720abddf8e379c4e1f23ed25f7702ef29ad08 Mon Sep 17 00:00:00 2001
From: Lorenz Kästle <12514511+RincewindsHat@users.noreply.github.com>
Date: Sun, 9 Nov 2025 11:46:36 +0100
Subject: check_smtp: certificate check is no longer opt-in

This is a breaking change.
Testing whether a TLS certificate is still valid (expiration wise)
is now the default in check_smtp.
The reasoning is, that in most scenarios an expired certificate
will effectively mean that the service is not working anymore due to
the refusal of other software to talk to it.

There is a new cli parameter though to explicitly ignore that.
---
 plugins/check_smtp.c          | 88 ++++++++++++++++++++++++-------------------
 plugins/check_smtp.d/config.h |  6 ++-
 2 files changed, 54 insertions(+), 40 deletions(-)

(limited to 'plugins')

diff --git a/plugins/check_smtp.c b/plugins/check_smtp.c
index cb92421c..e806ad29 100644
--- a/plugins/check_smtp.c
+++ b/plugins/check_smtp.c
@@ -37,6 +37,7 @@
 #include "base64.h"
 #include "regex.h"
 
+#include <bits/getopt_ext.h>
 #include <ctype.h>
 #include <string.h>
 #include "check_smtp.d/config.h"
@@ -347,9 +348,19 @@ int main(int argc, char **argv) {
 
 		switch (cert_check_result.errors) {
 		case ALL_OK: {
-			xasprintf(&sc_cert_check.output, "Certificate expiration. Remaining time %g days",
-					  cert_check_result.remaining_seconds / 86400);
-			sc_cert_check = mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
+
+			if (cert_check_result.result_state != STATE_OK &&
+				config.ignore_certificate_expiration) {
+				xasprintf(&sc_cert_check.output,
+						  "Remaining certificate lifetime: %d days. Expiration will be ignored",
+						  (int)(cert_check_result.remaining_seconds / 86400));
+				sc_cert_check = mp_set_subcheck_state(sc_cert_check, STATE_OK);
+			} else {
+				xasprintf(&sc_cert_check.output, "Remaining certificate lifetime: %d days",
+						  (int)(cert_check_result.remaining_seconds / 86400));
+				sc_cert_check =
+					mp_set_subcheck_state(sc_cert_check, cert_check_result.result_state);
+			}
 		} break;
 		case NO_SERVER_CERTIFICATE_PRESENT: {
 			xasprintf(&sc_cert_check.output, "no server certificate present");
@@ -366,12 +377,6 @@ int main(int argc, char **argv) {
 		};
 
 		mp_add_subcheck_to_check(&overall, sc_cert_check);
-
-		if (config.check_cert) {
-			smtp_quit(config, buffer, socket_descriptor, ssl_established);
-			my_close(socket_descriptor);
-			mp_exit(overall);
-		}
 	}
 #	endif /* USE_OPENSSL */
 
@@ -584,37 +589,40 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 	enum {
 		SNI_OPTION = CHAR_MAX + 1,
 		output_format_index,
+		ignore_certificate_expiration_index,
 	};
 
 	int option = 0;
-	static struct option longopts[] = {{"hostname", required_argument, 0, 'H'},
-									   {"expect", required_argument, 0, 'e'},
-									   {"critical", required_argument, 0, 'c'},
-									   {"warning", required_argument, 0, 'w'},
-									   {"timeout", required_argument, 0, 't'},
-									   {"port", required_argument, 0, 'p'},
-									   {"from", required_argument, 0, 'f'},
-									   {"fqdn", required_argument, 0, 'F'},
-									   {"authtype", required_argument, 0, 'A'},
-									   {"authuser", required_argument, 0, 'U'},
-									   {"authpass", required_argument, 0, 'P'},
-									   {"command", required_argument, 0, 'C'},
-									   {"response", required_argument, 0, 'R'},
-									   {"verbose", no_argument, 0, 'v'},
-									   {"version", no_argument, 0, 'V'},
-									   {"use-ipv4", no_argument, 0, '4'},
-									   {"use-ipv6", no_argument, 0, '6'},
-									   {"help", no_argument, 0, 'h'},
-									   {"lmtp", no_argument, 0, 'L'},
-									   {"ssl", no_argument, 0, 's'},
-									   {"tls", no_argument, 0, 's'},
-									   {"starttls", no_argument, 0, 'S'},
-									   {"sni", no_argument, 0, SNI_OPTION},
-									   {"certificate", required_argument, 0, 'D'},
-									   {"ignore-quit-failure", no_argument, 0, 'q'},
-									   {"proxy", no_argument, 0, 'r'},
-									   {"output-format", required_argument, 0, output_format_index},
-									   {0, 0, 0, 0}};
+	static struct option longopts[] = {
+		{"hostname", required_argument, 0, 'H'},
+		{"expect", required_argument, 0, 'e'},
+		{"critical", required_argument, 0, 'c'},
+		{"warning", required_argument, 0, 'w'},
+		{"timeout", required_argument, 0, 't'},
+		{"port", required_argument, 0, 'p'},
+		{"from", required_argument, 0, 'f'},
+		{"fqdn", required_argument, 0, 'F'},
+		{"authtype", required_argument, 0, 'A'},
+		{"authuser", required_argument, 0, 'U'},
+		{"authpass", required_argument, 0, 'P'},
+		{"command", required_argument, 0, 'C'},
+		{"response", required_argument, 0, 'R'},
+		{"verbose", no_argument, 0, 'v'},
+		{"version", no_argument, 0, 'V'},
+		{"use-ipv4", no_argument, 0, '4'},
+		{"use-ipv6", no_argument, 0, '6'},
+		{"help", no_argument, 0, 'h'},
+		{"lmtp", no_argument, 0, 'L'},
+		{"ssl", no_argument, 0, 's'},
+		{"tls", no_argument, 0, 's'},
+		{"starttls", no_argument, 0, 'S'},
+		{"sni", no_argument, 0, SNI_OPTION},
+		{"certificate", required_argument, 0, 'D'},
+		{"ignore-quit-failure", no_argument, 0, 'q'},
+		{"proxy", no_argument, 0, 'r'},
+		{"ignore-certificate-expiration", no_argument, 0, ignore_certificate_expiration_index},
+		{"output-format", required_argument, 0, output_format_index},
+		{0, 0, 0, 0}};
 
 	check_smtp_config_wrapper result = {
 		.config = check_smtp_config_init(),
@@ -766,7 +774,6 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 				}
 				result.config.days_till_exp_warn = atoi(optarg);
 			}
-			result.config.check_cert = true;
 			result.config.ignore_send_quit_failure = true;
 #else
 			usage(_("SSL support not available - install OpenSSL and recompile"));
@@ -827,6 +834,9 @@ check_smtp_config_wrapper process_arguments(int argc, char **argv) {
 			result.config.output_format = parser.output_format;
 			break;
 		}
+		case ignore_certificate_expiration_index: {
+			result.config.ignore_certificate_expiration = true;
+		}
 		}
 	}
 
@@ -1028,6 +1038,8 @@ void print_help(void) {
 	printf("    %s\n", _("Send LHLO instead of HELO/EHLO"));
 	printf(" %s\n", "-q, --ignore-quit-failure");
 	printf("    %s\n", _("Ignore failure when sending QUIT command to server"));
+	printf(" %s\n", "--ignore-certificate-expiration");
+	printf("    %s\n", _("Ignore certificate expiration"));
 
 	printf(UT_WARN_CRIT);
 
diff --git a/plugins/check_smtp.d/config.h b/plugins/check_smtp.d/config.h
index 11d7fe56..b0d42ed1 100644
--- a/plugins/check_smtp.d/config.h
+++ b/plugins/check_smtp.d/config.h
@@ -40,12 +40,13 @@ typedef struct {
 
 	bool use_proxy_prefix;
 #ifdef HAVE_SSL
-	bool check_cert;
 	int days_till_exp_warn;
 	int days_till_exp_crit;
 	bool use_ssl;
 	bool use_starttls;
 	bool use_sni;
+
+	bool ignore_certificate_expiration;
 #endif
 
 	bool output_format_is_set;
@@ -80,12 +81,13 @@ check_smtp_config check_smtp_config_init() {
 
 		.use_proxy_prefix = false,
 #ifdef HAVE_SSL
-		.check_cert = false,
 		.days_till_exp_warn = 0,
 		.days_till_exp_crit = 0,
 		.use_ssl = false,
 		.use_starttls = false,
 		.use_sni = false,
+
+		.ignore_certificate_expiration = false,
 #endif
 
 		.output_format_is_set = false,
-- 
cgit v1.2.3-74-g34f1