master: Log a warning at startup if fd limit is too low.

diff --git a/src/master/master-settings.c b/src/master/master-settings.c
index 4f495273c8363f95aa7ec987ca14ebe2f31b5115..eeb9fefb6ce8fbaa437c2889af637854206c58b0 100644 (file)
--- a/src/master/master-settings.c
+++ b/src/master/master-settings.c
@@ -9,6 +9,7 @@
 #include "ipwd.h"
 #include "mkdir-parents.h"
 #include "safe-mkdir.h"
+#include "restrict-process-size.h"
 #include "settings-parser.h"
 #include "master-settings.h"
 
@@ -403,6 +404,8 @@ master_settings_verify(void *_set, pool_t pool, const char **error_r)
        static int warned_auth = FALSE, warned_anvil = FALSE;
 #ifdef CONFIG_BINARY
        const struct service_settings *default_service;
+#else
+       rlim_t fd_limit;
 #endif
        struct master_settings *set = _set;
        struct service_settings *const *services;
@@ -411,6 +414,8 @@ master_settings_verify(void *_set, pool_t pool, const char **error_r)
        struct passwd pw;
        unsigned int i, j, count, len, client_limit, process_limit;
        unsigned int max_auth_client_processes, max_anvil_client_processes;
+       const char *max_client_limit_source = "default_client_count";
+       unsigned int max_client_limit;
 
        len = strlen(set->base_dir);
        if (len > 0 && set->base_dir[len-1] == '/') {
@@ -484,6 +489,7 @@ master_settings_verify(void *_set, pool_t pool, const char **error_r)
                }
        }
        t_array_init(&all_listeners, 64);
+       max_client_limit = set->default_client_limit;
        max_auth_client_processes = 0;
        max_anvil_client_processes = 2; /* blocking, nonblocking pipes */
        for (i = 0; i < count; i++) {
@@ -525,6 +531,11 @@ master_settings_verify(void *_set, pool_t pool, const char **error_r)
                                "vsz_limit is too low", service->name);
                        return FALSE;
                }
+               if (max_client_limit < service->client_limit) {
+                       max_client_limit = service->client_limit;
+                       max_client_limit_source = t_strdup_printf(
+                               "service %s { client_limit }", service->name);
+               }
 
 #ifdef CONFIG_BINARY
                default_service =
@@ -570,6 +581,15 @@ master_settings_verify(void *_set, pool_t pool, const char **error_r)
                          "required under max. load (%u)",
                          client_limit, max_anvil_client_processes);
        }
+#ifndef CONFIG_BINARY
+       if (restrict_get_fd_limit(&fd_limit) == 0 &&
+           fd_limit < (rlim_t)max_client_limit) {
+               i_warning("fd limit (ulimit -n) is lower than required "
+                         "under max. load (%u < %u), because of %s",
+                         (unsigned int)fd_limit, max_client_limit,
+                         max_client_limit_source);
+       }
+#endif
 
        /* check for duplicate listeners */
        array_sort(&all_listeners, i_strcmp_p);