lib-master: Try to use binary config cache if DOVECOT_CONFIG_CACHE environment is set

diff --git a/src/lib-master/master-service-settings.c b/src/lib-master/master-service-settings.c
index b48bf28797d011c2a04a39b3a128d556ea2a953d..162f34dbefbcbed8785274a2fdc17b9ffddcbd0b 100644 (file)
--- a/src/lib-master/master-service-settings.c
+++ b/src/lib-master/master-service-settings.c
@@ -20,6 +20,7 @@
 #include "master-service-settings.h"
 
 #include <unistd.h>
+#include <fcntl.h>
 #include <time.h>
 #include <sys/stat.h>
 
@@ -318,17 +319,38 @@ config_exec_fallback(struct master_service *service,
        errno = saved_errno;
 }
 
+static int master_service_binary_config_cache_get(const char *cache_dir,
+                                                 const char *input_path)
+{
+       if (cache_dir == NULL)
+               return -1;
+
+       const char *cache_path =
+               master_service_get_binary_config_cache_path(cache_dir, input_path);
+       int fd = open(cache_path, O_RDONLY);
+       if (fd == -1 && errno != ENOENT)
+               i_error("Binary config cache: open(%s) failed: %m", cache_path);
+       return fd;
+}
+
 static int
 master_service_open_config(struct master_service *service,
                           const struct master_service_settings_input *input,
-                          const char **path_r, const char **error_r)
+                          const char *cache_dir,
+                          const char **path_r, bool *cached_config_r,
+                          const char **error_r)
 {
        struct stat st;
        const char *path;
        int fd = -1;
 
+       *cached_config_r = FALSE;
        *path_r = path = input->config_path != NULL ? input->config_path :
                master_service_get_config_path(service);
+       if ((fd = master_service_binary_config_cache_get(cache_dir, path)) != -1) {
+               *cached_config_r = TRUE;
+               return fd;
+       }
 
        if (!service->config_path_from_master &&
            !service->config_path_changed_with_param &&
@@ -436,12 +458,15 @@ master_service_append_config_overrides(struct master_service *service)
        }
 }
 
-int master_service_settings_read(struct master_service *service,
+static int
+master_service_settings_read_int(struct master_service *service,
                                 const struct master_service_settings_input *input,
+                                const char *cache_dir,
                                 struct master_service_settings_output *output_r,
                                 const char **error_r)
 {
        const char *path = NULL, *value, *error;
+       bool cached_config = FALSE;
        int ret, fd = -1;
 
        i_zero(output_r);
@@ -464,8 +489,9 @@ int master_service_settings_read(struct master_service *service,
                /* Open config via socket if possible. If it doesn't work,
                   execute doveconf -F. */
                T_BEGIN {
-                       fd = master_service_open_config(service, input, &path,
-                                                       &error);
+                       fd = master_service_open_config(service, input,
+                                                       cache_dir, &path,
+                                                       &cached_config, &error);
                } T_END_PASS_STR_IF(fd == -1, &error);
                if (fd == -1) {
                        if (errno == EACCES)
@@ -500,10 +526,18 @@ int master_service_settings_read(struct master_service *service,
                enum settings_read_flags read_flags =
                        !input->no_protocol_filter ? 0 :
                        SETTINGS_READ_NO_PROTOCOL_FILTER;
+               if (cached_config)
+                       read_flags |= SETTINGS_READ_CHECK_CACHE_TIMESTAMPS;
                ret = settings_read(service->settings_root, fd, path,
                                    service_name, protocol_name, read_flags,
                                    &output_r->specific_protocols,
                                    &error);
+               if (ret == 0 && cached_config) {
+                       /* out-of-date binary config cache */
+                       i_close_fd(&fd);
+                       return master_service_settings_read_int(service, input,
+                                               NULL, output_r, error_r);
+               }
                if (input->return_config_fd)
                        output_r->config_fd = fd;
                else
@@ -553,6 +587,16 @@ int master_service_settings_read(struct master_service *service,
        return 0;
 }
 
+int master_service_settings_read(struct master_service *service,
+                                const struct master_service_settings_input *input,
+                                struct master_service_settings_output *output_r,
+                                const char **error_r)
+{
+       return master_service_settings_read_int(service, input,
+                                               getenv("DOVECOT_CONFIG_CACHE"),
+                                               output_r, error_r);
+}
+
 int master_service_settings_read_simple(struct master_service *service,
                                        const char **error_r)
 {