From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Sat, 17 Dec 2022 19:50:45 +0000 (+0200)
Subject: lib-master: Keep the config always mmap()ed
X-Git-Tag: 2.4.0~3055
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59d7e9d435662a11a3f9e432cac516dbea31369a;p=thirdparty%2Fdovecot%2Fcore.git

lib-master: Keep the config always mmap()ed

The config fd is no longer necessary to keep open.
---

diff --git a/src/lib-master/master-service-private.h b/src/lib-master/master-service-private.h
index 1052370e19..9a3d59fe66 100644
--- a/src/lib-master/master-service-private.h
+++ b/src/lib-master/master-service-private.h
@@ -38,7 +38,8 @@ struct master_service {
 	const char *version_string;
 	char *config_path;
 	ARRAY_TYPE(const_string) config_overrides;
-	int config_fd;
+	void *config_mmap_base;
+	size_t config_mmap_size;
 	int syslog_facility;
 	data_stack_frame_t datastack_frame_id;
 
diff --git a/src/lib-master/master-service-settings.c b/src/lib-master/master-service-settings.c
index 2ffd4d9f5c..45354dcbcd 100644
--- a/src/lib-master/master-service-settings.c
+++ b/src/lib-master/master-service-settings.c
@@ -548,10 +548,8 @@ int master_service_settings_read(struct master_service *service,
 	i_zero(output_r);
 	output_r->config_fd = -1;
 
-	if (service->config_fd != -1 && !input->reload_config) {
+	if (service->config_mmap_base != NULL && !input->reload_config) {
 		/* config was already read once */
-		fd = service->config_fd;
-		path = "<config fd>";
 	} else if ((value = getenv(DOVECOT_CONFIG_FD_ENV)) != NULL) {
 		/* doveconf -F parameter already executed us back.
 		   The configuration is in DOVECOT_CONFIG_FD. */
@@ -568,6 +566,27 @@ int master_service_settings_read(struct master_service *service,
 			return -1;
 		}
 	}
+	if (fd != -1) {
+		if (service->config_mmap_base != NULL) {
+			i_assert(input->reload_config);
+			if (munmap(service->config_mmap_base,
+				   service->config_mmap_size) < 0)
+				i_error("munmap(<config>) failed: %m");
+		}
+
+		service->config_mmap_base =
+			mmap_ro_file(fd, &service->config_mmap_size);
+		if (service->config_mmap_base == MAP_FAILED)
+			i_fatal("Failed to read config: mmap(%s) failed: %m", path);
+		if (service->config_mmap_size == 0)
+			i_fatal("Failed to read config: %s file size is empty", path);
+
+		if (input->return_config_fd)
+			output_r->config_fd = fd;
+		else
+			i_close_fd(&fd);
+		env_remove(DOVECOT_CONFIG_FD_ENV);
+	}
 
 	if (service->set_pool != NULL) {
 		if (service->set_parser != NULL)
@@ -604,46 +623,22 @@ int master_service_settings_read(struct master_service *service,
 			array_front(&all_roots), array_count(&all_roots),
 			SETTINGS_PARSER_FLAG_IGNORE_UNKNOWN_KEYS);
 
-	/* fd is unset only if MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS is used */
-	if (fd != -1) {
-		size_t mmap_size;
-		void *mmap_base = mmap_ro_file(fd, &mmap_size);
-		if (mmap_base == MAP_FAILED)
-			i_fatal("mmap(%s) failed: %m", path);
-		if (mmap_size == 0)
-			i_fatal("%s file size is empty", path);
-
+	/* config_mmap_base is NULL only if
+	   MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS is used */
+	if (service->config_mmap_base != NULL) {
 		ret = master_service_settings_read_mmap(parser, event,
-							mmap_base, mmap_size,
-							output_r, error_r);
-		if (munmap(mmap_base, mmap_size) < 0)
-			i_fatal("munmap(%s) failed: %m", path);
+			service->config_mmap_base, service->config_mmap_size,
+			output_r, error_r);
 
 		if (ret < 0) {
 			if (getenv(DOVECOT_CONFIG_FD_ENV) != NULL) {
 				i_fatal("Failed to parse config from fd %d: %s",
 					fd, *error_r);
 			}
-			i_close_fd(&fd);
 			settings_parser_unref(&parser);
 			event_unref(&event);
 			return -1;
 		}
-
-		if (input->return_config_fd) {
-			output_r->config_fd = dup(fd);
-			if (output_r->config_fd == -1)
-				i_fatal("dup(%s) failed: %m", path);
-		}
-		if (input->config_path == NULL) {
-			i_assert(service->config_fd == -1 ||
-				 service->config_fd == fd);
-			service->config_fd = fd;
-			fd_close_on_exec(service->config_fd, TRUE);
-		} else {
-			i_close_fd(&fd);
-		}
-		env_remove(DOVECOT_CONFIG_FD_ENV);
 	}
 	event_unref(&event);
 
diff --git a/src/lib-master/master-service.c b/src/lib-master/master-service.c
index 73f5e327ed..932d10a0f4 100644
--- a/src/lib-master/master-service.c
+++ b/src/lib-master/master-service.c
@@ -12,6 +12,7 @@
 #include "str.h"
 #include "strescape.h"
 #include "env-util.h"
+#include "mmap-util.h"
 #include "home-expand.h"
 #include "process-title.h"
 #include "time-util.h"
@@ -516,7 +517,6 @@ master_service_init(const char *name, enum master_service_flags flags,
 	service->flags = flags;
 	service->ioloop = io_loop_create();
 	service->service_count_left = UINT_MAX;
-	service->config_fd = -1;
 	service->datastack_frame_id = datastack_frame_id;
 
 	service->config_path = i_strdup(getenv(MASTER_CONFIG_FILE_ENV));
@@ -1521,7 +1521,6 @@ static void master_service_deinit_real(struct master_service **_service)
 
 	if (service->stats_client != NULL)
 		stats_client_deinit(&service->stats_client);
-	i_close_fd(&service->config_fd);
 	timeout_remove(&service->to_overflow_call);
 	timeout_remove(&service->to_die);
 	timeout_remove(&service->to_overflow_state);
@@ -1535,6 +1534,11 @@ static void master_service_deinit_real(struct master_service **_service)
 		settings_parser_unref(&service->set_parser);
 		pool_unref(&service->set_pool);
 	}
+	if (service->config_mmap_base != NULL) {
+		if (munmap(service->config_mmap_base,
+			   service->config_mmap_size) < 0)
+			i_error("munmap(<config>) failed: %m");
+	}
 	i_free(master_service_category_name);
 	master_service_category.name = NULL;
 	event_unregister_callback(master_service_event_callback);