lib-master: Execute doveconf with -F parameter as the config fallback

This changes settings to be read via a fd instead of environment.

As a side effect, this fixes a bug where if the settings output was larger
than 128 kB in Linux, exec() would fail with "Argument list too long".

lib-master preserves support for reading settings from environment for a
few more commits, because the log process uses it to read its settings.

diff --git a/src/lib-master/master-service-settings.c b/src/lib-master/master-service-settings.c
index c78013e964238efe76e1fcde8d3fb4ece927719a..6772c4ed5fedda78721933167a92d4386af36368 100644 (file)
--- a/src/lib-master/master-service-settings.c
+++ b/src/lib-master/master-service-settings.c
@@ -210,35 +210,10 @@ master_service_exec_config(struct master_service *service,
 
        t_array_init(&conf_argv, 11 + (service->argc + 1) + 1);
        strarr_push(&conf_argv, DOVECOT_CONFIG_BIN_PATH);
-       if (input->service != NULL) {
-               strarr_push(&conf_argv, "-f");
-               strarr_push(&conf_argv,
-                           t_strconcat("service=", input->service, NULL));
-       }
        strarr_push(&conf_argv, "-c");
        strarr_push(&conf_argv, service->config_path);
-       if (input->module != NULL) {
-               strarr_push(&conf_argv, "-m");
-               strarr_push(&conf_argv, input->module);
-       }
-       if (input->extra_modules != NULL) {
-               for (unsigned int i = 0; input->extra_modules[i] != NULL; i++) {
-                       strarr_push(&conf_argv, "-m");
-                       strarr_push(&conf_argv, input->extra_modules[i]);
-               }
-       }
-       if ((service->flags & MASTER_SERVICE_FLAG_DISABLE_SSL_SET) == 0 &&
-           (input->module != NULL || input->extra_modules != NULL)) {
-               strarr_push(&conf_argv, "-m");
-               if (service->want_ssl_server)
-                       strarr_push(&conf_argv, "ssl-server");
-               else
-                       strarr_push(&conf_argv, "ssl");
-       }
-       if (input->parse_full_config)
-               strarr_push(&conf_argv, "-p");
 
-       strarr_push(&conf_argv, "-e");
+       strarr_push(&conf_argv, "-F");
        strarr_push(&conf_argv, binary_path);
        array_append(&conf_argv, (const char *const *)service->argv + 1,
                     service->argc);
@@ -405,6 +380,7 @@ void master_service_config_socket_try_open(struct master_service *service)
           ignore it later on. (unfortunately there isn't a master_service_*()
           call where this function would be better called.) */
        if (getenv("DOVECONF_ENV") != NULL ||
+           getenv(DOVECOT_CONFIG_FD_ENV) != NULL ||
            (service->flags & MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS) != 0)
                return;
 
@@ -521,15 +497,25 @@ int master_service_settings_read(struct master_service *service,
        const struct setting_parser_info *tmp_root;
        struct setting_parser_context *parser;
        struct istream *istream;
-       const char *path = NULL, *error;
+       const char *path = NULL, *value, *error;
        unsigned int i;
        int ret, fd = -1;
-       bool use_environment, retry;
+       bool use_environment = FALSE, retry;
 
        i_zero(output_r);
 
-       if (getenv("DOVECONF_ENV") == NULL &&
-           (service->flags & MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS) == 0) {
+       value = getenv(DOVECOT_CONFIG_FD_ENV);
+       if (value != NULL) {
+               /* doveconf -F parameter already executed us back.
+                  The configuration is in DOVECOT_CONFIG_FD. */
+               if (str_to_int(value, &fd) < 0 || fd < 0)
+                       i_fatal("Invalid "DOVECOT_CONFIG_FD_ENV": %s", value);
+       } else if (getenv("DOVECONF_ENV") != NULL) {
+               use_environment = (service->flags &
+                                  MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS) == 0;
+       } else if ((service->flags & MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS) == 0) {
+               /* Open config via socket if possible. If it doesn't work,
+                  execute doveconf -F. */
                retry = service->config_fd != -1;
                for (;;) {
                        fd = master_service_open_config(service, input,
@@ -596,6 +582,10 @@ int master_service_settings_read(struct master_service *service,
                i_stream_unref(&istream);
 
                if (ret < 0) {
+                       if (getenv(DOVECOT_CONFIG_FD_ENV) != NULL) {
+                               i_fatal("Failed to read config from fd %d: %s",
+                                       fd, *error_r);
+                       }
                        i_close_fd(&fd);
                        config_exec_fallback(service, input, error_r);
                        settings_parser_unref(&parser);
@@ -604,14 +594,12 @@ int master_service_settings_read(struct master_service *service,
                }
 
                if ((service->flags & MASTER_SERVICE_FLAG_KEEP_CONFIG_OPEN) != 0 &&
-                   service->config_fd == -1 && input->config_path == NULL)
+                   service->config_fd == -1 && input->config_path == NULL &&
+                   getenv(DOVECOT_CONFIG_FD_ENV) == NULL)
                        service->config_fd = fd;
                else
                        i_close_fd(&fd);
-               use_environment = FALSE;
-       } else {
-               use_environment = (service->flags &
-                                  MASTER_SERVICE_FLAG_NO_CONFIG_SETTINGS) == 0;
+               env_remove(DOVECOT_CONFIG_FD_ENV);
        }
        event_unref(&event);