From 0730917115f2f2df04ef7d9c075fcef907d29708 Mon Sep 17 00:00:00 2001
From: Dirk Engling <erdgeist@erdgeist.org>
Date: Fri, 4 Dec 2020 06:20:54 +0100
Subject: Add walker that closes unused files after 20 minutes

---
 receiver.c | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/receiver.c b/receiver.c
index 36b649c..0fe24a2 100644
--- a/receiver.c
+++ b/receiver.c
@@ -47,6 +47,9 @@ static const unsigned char privkey[] =
 
 static const unsigned char pp[] = "IJUHZGFDXTZKHJKHGFDHZLUÖDRTFGHHJGHH";
 
+// Close files after 20 minutes
+#define ACCESS_TIMEOUT (20*60)
+
 /*
    1 byte type: 0 allocate session, 1 log to session, rest: discard
    8 bytes session id
@@ -74,7 +77,7 @@ static size_t g_session_count = 0;
 
 int session_compare(const void *a, const void *b) { return memcmp(a, b, 8); }
 
-enum { SIDOFFS = 20, KEYOFFS = 37, };
+enum { SIDOFFS = 20, KEYOFFS = 37 };
 
 static uint8_t hex2nyble(char c)
 {
@@ -238,6 +241,17 @@ static void log_to_session(const uint8_t *packet, size_t len) {
     mbedtls_gcm_free(&ctx);
 }
 
+void close_files() {
+    time_t jetzt = now();
+    for (int i=0; i<g_session_count; ++i)
+        if (g_sessions[i].fd >= 0 &&
+            g_sessions[i].last_access != 0 &&
+            jetzt - g_sessions[i].last_access > ACCESS_TIMEOUT) {
+            close(g_sessions[i].fd);
+            g_sessions[i].fd = -1;
+            }
+}
+
 int main() {
     mbedtls_ctr_drbg_context ctr_drbg;
     mbedtls_entropy_context entropy;
@@ -270,6 +284,7 @@ int main() {
 
     import_sessions(".");
 
+    time_t last_close_check = now();
     while(1) {
         uint8_t packet[16*1024];
         uint8_t rsa_plain_text[AES_KEY_LENGTH];
@@ -294,5 +309,10 @@ int main() {
         default:
             break;
         }
+        time_t jetzt = now();
+        if (jetzt > last_close_check + 60) {
+            close_files();
+            last_close_check = jetzt;
+        }
     }
 }
-- 
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