Use sigchld to clean up zombie process. (#1062)

SIGKILL doesn't mean waitpid may immediate get any result.
fcitx · May 24, 2024 · efb0bbc · efb0bbc
1 parent 7b29490
commit efb0bbc
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Showing 6 changed files with 49 additions and 5 deletions.
diff --git a/src/lib/fcitx/instance.cpp b/src/lib/fcitx/instance.cpp
@@ -10,6 +10,8 @@
 #include <signal.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <cstdint>
+#include <ctime>
 #include <memory>
 #include <stdexcept>
 #include <unordered_map>
@@ -22,6 +24,7 @@
 #include "fcitx-utils/eventdispatcher.h"
 #include "fcitx-utils/i18n.h"
 #include "fcitx-utils/log.h"
+#include "fcitx-utils/macros.h"
 #include "fcitx-utils/misc.h"
 #include "fcitx-utils/standardpath.h"
 #include "fcitx-utils/stringutils.h"
@@ -1361,6 +1364,9 @@ void Instance::handleSignal() {
             exit();
         } else if (signo == SIGUSR1) {
             reloadConfig();
+        } else if (signo == SIGCHLD) {
+            d->zombieReaper_->setNextInterval(2000000);
+            d->zombieReaper_->setOneShot();
         }
     }
 }
@@ -1411,6 +1417,15 @@ void Instance::initialize() {
             }
             return false;
         });
+    d->zombieReaper_ = d->eventLoop_.addTimeEvent(
+        CLOCK_MONOTONIC, now(CLOCK_MONOTONIC), 0,
+        [](EventSourceTime *, uint64_t) {
+            pid_t res;
+            while ((res = waitpid(-1, nullptr, WNOHANG)) > 0) {
+            }
+            return false;
+        });
+    d->zombieReaper_->setEnabled(false);
 
     d->exitEvent_ = d->eventLoop_.addExitEvent([this](EventSource *) {
         FCITX_DEBUG() << "Running save...";

diff --git a/src/lib/fcitx/instance_p.h b/src/lib/fcitx/instance_p.h
@@ -165,6 +165,7 @@ class InstancePrivate : public QPtrHolder<Instance> {
     EventDispatcher eventDispatcher_;
     std::unique_ptr<EventSourceIO> signalPipeEvent_;
     std::unique_ptr<EventSourceTime> preloadInputMethodEvent_;
+    std::unique_ptr<EventSourceTime> zombieReaper_;
     std::unique_ptr<EventSource> exitEvent_;
     InputContextManager icManager_;
     AddonManager addonManager_;

diff --git a/src/server/errorhandler.cpp b/src/server/errorhandler.cpp
@@ -11,8 +11,11 @@
 #include <fcntl.h>
 #include <signal.h>
 #include <string.h>
+#include <sys/wait.h>
 #include <time.h>
 #include <unistd.h>
+#include <cstdint>
+#include <string>
 
 #include "fcitx-utils/fs.h"
 #include "errorhandler.h"
@@ -31,12 +34,12 @@
 extern int selfpipe[2];
 extern std::string crashlog;
 
-typedef struct _MinimalBuffer {
+struct MinimalBuffer {
     char buffer[MINIMAL_BUFFER_SIZE];
     int offset;
-} MinimalBuffer;
+};
 
-void SetMyExceptionHandler(void) {
+void SetMyExceptionHandler() {
     int signo;
 
     for (signo = SIGHUP; signo < SIGUNUSED; signo++) {
@@ -111,6 +114,9 @@ static inline void _write_buffer(int fd, const MinimalBuffer *buffer) {
 
 void OnException(int signo) {
     if (signo == SIGCHLD) {
+        uint8_t sig = (signo & 0xff);
+        fcitx::fs::safeWrite(selfpipe[1], &sig, 1);
+        signal(signo, OnException);
         return;
     }
 

diff --git a/src/server/main.cpp b/src/server/main.cpp
@@ -7,13 +7,21 @@
 
 #include <locale.h>
 #include <sys/stat.h>
+#include <cstdio>
+#include <cstdlib>
 #include <exception>
 #include <iostream>
+#include <string>
+#include <utility>
+#include <vector>
 #include "fcitx-utils/fs.h"
+#include "fcitx-utils/log.h"
 #include "fcitx-utils/misc.h"
 #include "fcitx-utils/misc_p.h"
 #include "fcitx-utils/standardpath.h"
+#include "fcitx-utils/stringutils.h"
 #include "fcitx/addonfactory.h"
+#include "fcitx/addonloader.h"
 #include "fcitx/addonmanager.h"
 #include "fcitx/instance.h"
 #include "errorhandler.h"
@@ -78,7 +86,7 @@ int main(int argc, char *argv[]) {
         canRestart = instance.canRestart();
     } catch (const InstanceQuietQuit &) {
     } catch (const std::exception &e) {
-        std::cerr << "Received exception: " << e.what() << std::endl;
+        std::cerr << "Received exception: " << e.what() << '\n';
         return 1;
     }
 

diff --git a/src/ui/classic/plasmathemewatchdog.cpp b/src/ui/classic/plasmathemewatchdog.cpp
@@ -5,12 +5,23 @@
  *
  */
 #include "plasmathemewatchdog.h"
+#include <fcntl.h>
+#include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
+#include <cassert>
+#include <cerrno>
+#include <csignal>
+#include <cstdint>
+#include <functional>
 #include <stdexcept>
+#include <string>
+#include <utility>
+#include <linux/prctl.h>
 #include "fcitx-utils/event.h"
-#include "fcitx-utils/misc_p.h"
+#include "fcitx-utils/fs.h"
 #include "fcitx-utils/standardpath.h"
+#include "fcitx-utils/unixfd.h"
 #include "common.h"
 
 #if defined(__FreeBSD__)

diff --git a/src/ui/classic/plasmathemewatchdog.h b/src/ui/classic/plasmathemewatchdog.h
@@ -7,7 +7,10 @@
 #ifndef _FCITX5_UI_CLASSIC_PLASMATHEMEWATCHDOG_H_
 #define _FCITX5_UI_CLASSIC_PLASMATHEMEWATCHDOG_H_
 
+#include <sys/types.h>
+#include <unistd.h>
 #include <functional>
+#include <memory>
 #include "fcitx-utils/event.h"
 #include "fcitx-utils/unixfd.h"