From 85d55c850de6bc1c3dfbdf346dc086745f124454 Mon Sep 17 00:00:00 2001
From: Philipp Schafft <lion@lion.leolix.org>
Date: Sat, 19 Mar 2022 17:09:55 +0000
Subject: [PATCH] Feature: Warn about FD_SETSIZE being too small

---
 src/admin.c   |  8 ++++++++
 src/cfgfile.c | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/admin.c b/src/admin.c
index 7878f73b..72270dd7 100644
--- a/src/admin.c
+++ b/src/admin.c
@@ -33,6 +33,10 @@
 #include <sys/resource.h>
 #endif
 
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
 #ifdef HAVE_OPENSSL
 #include <openssl/opensslv.h>
 #endif
@@ -1836,6 +1840,10 @@ static void command_version             (client_t *client, source_t *source, adm
     reportxml_helper_add_value_string(resource, "version", ICECAST_VERSION_STRING);
     reportxml_helper_add_value_int(resource, "address-bits", sizeof(void*)*8);
 
+#ifdef HAVE_SYS_SELECT_H
+    reportxml_helper_add_value_int(resource, "fd-set-size", FD_SETSIZE);
+#endif
+
 #ifdef HAVE_GETHOSTNAME
     if (true) {
         char hostname[80];
diff --git a/src/cfgfile.c b/src/cfgfile.c
index 94f2a0c4..272ce316 100644
--- a/src/cfgfile.c
+++ b/src/cfgfile.c
@@ -25,6 +25,9 @@
 #ifndef _WIN32
 #include <fnmatch.h>
 #endif
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
 #include <libxml/xmlmemory.h>
 #include <libxml/parser.h>
 #include <libxml/uri.h>
@@ -1045,6 +1048,13 @@ int config_parse_file(const char *filename, ice_config_t *configuration)
         ICECAST_LOG_ERROR("Client limit (%i) is too small for given source limit (%i)", configuration->client_limit, configuration->source_limit);
     }
 
+#ifndef HAVE_POLL
+    if (configuration->client_limit > (FD_SETSIZE - 32)) {
+        configuration->config_problems |= CONFIG_PROBLEM_VALIDATION;
+        ICECAST_LOG_ERROR("Client limit (%i) is too big for FD_SETSIZE (%i)", configuration->client_limit, FD_SETSIZE);
+    }
+#endif
+
     return 0;
 }