From 9ea40b479309fdca9518f30ace51a9329ca96665 Mon Sep 17 00:00:00 2001
From: Lorenz Stechauner <lorenz.stechauner@necronda.net>
Date: Fri, 5 Jun 2026 11:15:00 +0200
Subject: [PATCH] async: Remove old fds in epoll instance

---
 src/async.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/async.c b/src/async.c
index 615c9c5..ad0c717 100644
--- a/src/async.c
+++ b/src/async.c
@@ -258,7 +258,7 @@ void async_free(void) {
 
 void async_thread(void) {
     struct epoll_event ev, events[ASYNC_MAX_EVENTS];
-    int num_fds;
+    int num_fds, idx;
     long ts, min_ts, cur_ts;
     volatile listen_queue_t *l;
     evt_listen_t **local;
@@ -303,14 +303,21 @@ void async_thread(void) {
                     // fd already exists, delete old one
                     warning("Unable to add file descriptor to epoll instance");
                     errno = 0;
-                    if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, evt->fd, NULL) != -1)
+                    if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, evt->fd, NULL) != -1) {
+                        local = list_delete(local, evt);
+                        if (local == NULL) {
+                            critical("Unable to resize async local list");
+                            return;
+                        }
+                        notice("Removed old file descriptor from epoll instance");
                         continue;
+                    }
                 } else if (errno == EBADF || errno == EPERM) {
                     // fd probably already closed or does not support epoll somehow
                     // FIXME should not happen
                     warning("Unable to add file descriptor to epoll instance");
                     errno = 0;
-                    local = list_delete(local, &evt);
+                    local = list_remove(local, list_size(local) - 1);
                     if (local == NULL) {
                         critical("Unable to resize async local list");
                         return;
@@ -328,7 +335,7 @@ void async_thread(void) {
         // calculate wait timeout
         min_ts = -1000, cur_ts = clock_micros();
         for (int i = 0; i < list_size(local); i++) {
-            evt_listen_t *evt = local[i];
+            const evt_listen_t *evt = local[i];
             if (!evt->socket || evt->socket->timeout_us < 0) continue;
 
             ts = evt->socket->ts_last + evt->socket->timeout_us - cur_ts;
@@ -349,7 +356,10 @@ void async_thread(void) {
 
         for (int i = 0; i < num_fds; i++) {
             evt_listen_t *evt = events[i].data.ptr;
-            if (!list_contains(local, &evt)) continue;
+            if ((idx = list_find(local, &evt)) == -1) {
+                error("epoll instance reported event not contained in local list");
+                continue;
+            }
 
             void (*cb)(void *) = NULL;
             if (async_exec_cb(evt, async_e2a(events[i].events), &cb) == 0) {
@@ -364,7 +374,7 @@ void async_thread(void) {
                     }
                 }
 
-                local = list_delete(local, &evt);
+                local = list_remove(local, idx);
                 if (local == NULL) {
                     critical("Unable to resize async local list");
                     return;
@@ -381,7 +391,7 @@ void async_thread(void) {
         // check, if some socket ran into a timeout
         cur_ts = clock_micros();
         for (int i = 0; i < list_size(local); i++) {
-            evt_listen_t *evt = local[i];
+            const evt_listen_t *evt = local[i];
             if (!evt->socket) continue;
 
             if (evt->socket->timeout_us >= 0 && (cur_ts - evt->socket->ts_last) >= evt->socket->timeout_us) {