From 9d9e0a8e895fb63e756c808eaa12bfa7f7c6fb4a Mon Sep 17 00:00:00 2001
From: chenkeyu <chenkeyu13@huawei.com>
Date: Thu, 6 Feb 2025 21:02:45 +0800
Subject: [PATCH] fix timer epoll_ctl operate on closed fd

Issue: https://gitee.com/openharmony/commonlibrary_c_utils/issues/IBKHV4
Signed-off-by: chenkeyu <chenkeyu13@huawei.com>
---
 base/src/event_demultiplexer.cpp | 29 ++++++++++++++++++++++++-----
 base/src/event_demultiplexer.h   |  4 ++++
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/base/src/event_demultiplexer.cpp b/base/src/event_demultiplexer.cpp
index 84ce34f..6d93eef 100644
--- a/base/src/event_demultiplexer.cpp
+++ b/base/src/event_demultiplexer.cpp
@@ -33,7 +33,8 @@ static const int EPOLL_ERROR_BADF = 9;
 static const int EPOLL_ERROR_EINVAL = 22;
 
 EventDemultiplexer::EventDemultiplexer()
-    : epollFd_(epoll_create1(EPOLL_CLOEXEC)), maxEvents_(EPOLL_MAX_EVENS_INIT), mutex_(), eventHandlers_()
+    : epollFd_(epoll_create1(EPOLL_CLOEXEC)), maxEvents_(EPOLL_MAX_EVENS_INIT), mutex_(), eventHandlers_(),
+    notFoundFds_(), epollCtlErrno_(0)
 {
 }
 
@@ -71,6 +72,11 @@ uint32_t EventDemultiplexer::UpdateEventHandler(EventHandler* handler)
     auto itor = eventHandlers_.find(handler->GetHandle());
     if (itor == eventHandlers_.end()) {
         eventHandlers_.insert(std::make_pair(handler->GetHandle(), handler->shared_from_this()));
+        // fd num reuse by a new timerfd, remove it from notFoundFds
+        auto notFoundFdItor = notFoundFds_.find(handler->GetHandle());
+        if (notFoundFdItor != notFoundFds_.end()) {
+            notFoundFds_.erase(handler->GetHandle());
+        }
         return Update(EPOLL_CTL_ADD, handler);
     }
 
@@ -95,11 +101,25 @@ uint32_t EventDemultiplexer::Update(int operation, EventHandler* handler)
     if (epoll_ctl(epollFd_, operation, handler->GetHandle(), &event) != 0) {
         UTILS_LOGD("epoll_ctl %{public}d  operation %{public}d on handle %{public}d failed",
             epollFd_, operation, handler->GetHandle());
+        epollCtlErrno_ = errno;
         return TIMER_ERR_DEAL_FAILED;
     }
     return TIMER_ERR_OK;
 }
 
+void EventDemultiplexer::HandleNotFoundFds(int targetFd)
+{
+    auto targetFdItor = notFoundFds_.find(targetFd);
+    if (targetFdItor != notFoundFds_.end()) {
+        notFoundFds_.insert(targetFd);
+    } else {
+        if (epoll_ctl(epollFd_, EPOLL_CTL_DEL, targetFd, nullptr) == -1) {
+            UTILS_LOGE("failed to DEL %{public}d from epoll, errno: %{public}d", targetFd, errno);
+        }
+        notFoundFds_.erase(targetFd);
+    }
+}
+
 int EventDemultiplexer::Polling(int timeout /* ms */)
 {
     std::vector<struct epoll_event> epollEvents(maxEvents_);
@@ -133,10 +153,9 @@ int EventDemultiplexer::Polling(int timeout /* ms */)
                 taskQue.emplace_back(itor->second);
                 eventQue.emplace_back(events);
             } else {
-                UTILS_LOGE("fd not found in eventHandlers_, fd=%{public}d, events=%{public}d", targetFd, events);
-                if (epoll_ctl(epollFd_, EPOLL_CTL_DEL, targetFd, nullptr) == -1) {
-                    UTILS_LOGE("failed to DEL %{public}d from epoll, errno: %{public}d", targetFd, errno);
-                }
+                UTILS_LOGE("fd not found in eventHandlers_, fd=%{public}d, events=%{public}d, errno=%{public}d, setsize=%{public}zu", 
+                    targetFd, events, epollCtlErrno_, notFoundFds_.size());
+                HandleNotFoundFds(targetFd);
             }
         }
     }
diff --git a/base/src/event_demultiplexer.h b/base/src/event_demultiplexer.h
index 75a3d7b..afc58f2 100644
--- a/base/src/event_demultiplexer.h
+++ b/base/src/event_demultiplexer.h
@@ -20,6 +20,7 @@
 #include <memory>
 #include <cstdint>
 #include <map>
+#include <set>
 
 namespace OHOS {
 namespace Utils {
@@ -42,6 +43,7 @@ public:
 
 private:
     uint32_t Update(int operation, EventHandler* handler);
+    void HandleNotFoundFds(int targetFd);
     static uint32_t Reactor2Epoll(uint32_t reactorEvent);
     static uint32_t Epoll2Reactor(uint32_t epollEvents);
 
@@ -49,6 +51,8 @@ private:
     int maxEvents_;
     std::recursive_mutex mutex_;
     std::map<int, std::shared_ptr<EventHandler>> eventHandlers_; // guard by mutex_
+    std::set<int> notFoundFds_;
+    int epollCtlErrno_;
 };
 
 }
-- 
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