1 files changed, 87 insertions, 0 deletions

diff --git a/ot_stats.c b/ot_stats.c
index a9f12cc..5edbe0a 100644
--- a/ot_stats.c
+++ b/ot_stats.c
@@ -19,6 +19,7 @@
 
 /* Opentracker */
 #include "ot_accesslist.h"
+#include "ot_event.h"
 #include "ot_hex.h"
 #include "ot_iovec.h"
 #include "ot_ip.h"
@@ -546,6 +547,92 @@ static void stats_return_everything(char **reply, const char *reply_end) {
   fmt_append(reply, reply_end, "</stats>");
 }
 
+/* The names as the Makefile spells them, so that what a binary reports maps
+   straight back onto the FEATURES lines it was built from */
+static const char *const build_features[] = {
+#ifdef WANT_V4_ONLY
+    "WANT_V4_ONLY",
+#endif
+#ifdef WANT_ACCESSLIST_BLACK
+    "WANT_ACCESSLIST_BLACK",
+#endif
+#ifdef WANT_ACCESSLIST_WHITE
+    "WANT_ACCESSLIST_WHITE",
+#endif
+#ifdef WANT_DYNAMIC_ACCESSLIST
+    "WANT_DYNAMIC_ACCESSLIST",
+#endif
+#ifdef WANT_SYNC_LIVE
+    "WANT_SYNC_LIVE",
+#endif
+#ifdef WANT_IP_FROM_QUERY_STRING
+    "WANT_IP_FROM_QUERY_STRING",
+#endif
+#ifdef WANT_IP_FROM_PROXY
+    "WANT_IP_FROM_PROXY",
+#endif
+#ifdef WANT_COMPRESSION_GZIP
+    "WANT_COMPRESSION_GZIP",
+#endif
+#ifdef WANT_COMPRESSION_GZIP_ALWAYS
+    "WANT_COMPRESSION_GZIP_ALWAYS",
+#endif
+#ifdef WANT_COMPRESSION_ZSTD
+    "WANT_COMPRESSION_ZSTD",
+#endif
+#ifdef WANT_COMPRESSION_ZSTD_ALWAYS
+    "WANT_COMPRESSION_ZSTD_ALWAYS",
+#endif
+#ifdef WANT_FULLSCRAPE
+    "WANT_FULLSCRAPE",
+#endif
+#ifdef WANT_MODEST_FULLSCRAPES
+    "WANT_MODEST_FULLSCRAPES",
+#endif
+#ifdef WANT_KEEPALIVE
+    "WANT_KEEPALIVE",
+#endif
+#ifdef WANT_RESTRICT_STATS
+    "WANT_RESTRICT_STATS",
+#endif
+#ifdef WANT_LOG_NUMWANT
+    "WANT_LOG_NUMWANT",
+#endif
+#ifdef WANT_SPOT_WOODPECKER
+    "WANT_SPOT_WOODPECKER",
+#endif
+#ifdef WANT_SYSLOGS
+    "WANT_SYSLOGS",
+#endif
+#ifdef WANT_DEV_RANDOM
+    "WANT_DEV_RANDOM",
+#endif
+#ifdef WANT_INSECURE_RANDOM_FALLBACK
+    "WANT_INSECURE_RANDOM_FALLBACK",
+#endif
+#ifdef _DEBUG
+    "_DEBUG",
+#endif
+#ifdef _DEBUG_HTTPERROR
+    "_DEBUG_HTTPERROR",
+#endif
+#ifdef _DEBUG_RANDOMTORRENTS
+    "_DEBUG_RANDOMTORRENTS",
+#endif
+    NULL};
+
+void stats_return_tracker_features(char **reply, const char *reply_end) {
+  size_t i;
+
+  fmt_append(reply, reply_end, "events: %s\n", event_mechanism());
+  fmt_append(reply, reply_end, "features:");
+  for (i = 0; build_features[i]; ++i)
+    fmt_append(reply, reply_end, " %s", build_features[i]);
+  if (!build_features[0])
+    fmt_append(reply, reply_end, " none");
+  fmt_append(reply, reply_end, "\n");
+}
+
 void stats_return_tracker_version(char **reply, const char *reply_end) {
   fmt_append(reply, reply_end, "opentracker %s", OT_VERSION);
   /* Empty when the build had no git to ask, which is what a release tarball