fsevent_watch : Fix "zombie" processes not dying

ext/fsevent_watch/TSICTString.c

@@ -113,27 +113,6 @@ static inline CFStringRef TSICTStringCreateStringFromIntermediateRepresentation(
     return string;
 }
 
-static inline CFDataRef TSICTStringCreateDataWithDataOfTypeAndFormat(CFDataRef data, TSITStringTag type, TSITStringFormat format)
-{
-    CFRetain(data);
-
-    if (format == kTSITStringFormatDefault) {
-        format = TSICTStringGetDefaultFormat();
-    }
-
-    TStringIRep* rep = TSICTStringCreateWithDataOfTypeAndFormat(data, type, format);
-    if (rep == NULL) {
-        return NULL;
-    }
-
-    CFDataRef result = TSICTStringCreateDataFromIntermediateRepresentation(rep);
-
-    TSICTStringDestroy(rep);
-    CFRelease(data);
-
-    return result;
-}
-
 static inline void TSICTStringAppendObjectToMutableDataWithFormat(CFTypeRef object, CFMutableDataRef buffer, TSITStringFormat format)
 {
     if (object == NULL) {

ext/fsevent_watch/main.c

@@ -1,4 +1,5 @@
 #include "common.h"
+#include "signal_handlers.h"
 #include "cli.h"
 #include "FSEventsFix.h"
 
@@ -470,6 +471,7 @@ static void callback(__attribute__((unused)) FSEventStreamRef streamRef,
 
 int main(int argc, const char* argv[])
 {
+  install_signal_handlers();
   parse_cli_settings(argc, argv);
 
   if (needs_fsevents_fix) {

ext/fsevent_watch/signal_handlers.c

@@ -0,0 +1,66 @@
+#include "signal_handlers.h"
+#include <fcntl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <unistd.h>
+
+
+#define PPID_ALARM_INTERVAL 2 // send SIGALRM every this seconds
+
+
+static pid_t orig_ppid;
+
+
+static void signal_handler(int _) {
+  exit(EXIT_FAILURE);
+}
+
+static void check_ppid(void) {
+  if (getppid() != orig_ppid) {
+    exit(EXIT_FAILURE);
+  }
+}
+
+static void check_stdout_open(void) {
+  if (fcntl(STDOUT_FILENO, F_GETFD) < 0) {
+    exit(EXIT_FAILURE);
+  }
+}
+
+static void alarm_handler(int _) {
+  check_ppid();
+  check_stdout_open();
+  alarm(PPID_ALARM_INTERVAL);
+  signal(SIGALRM, alarm_handler);
+}
+
+static void die(const char *msg) {
+  fprintf(stderr, "\nFATAL: %s\n", msg);
+  abort();
+}
+
+static void install_signal_handler(int sig, void (*handler)(int)) {
+  if (signal(sig, handler) == SIG_ERR) {
+    die("Could not install signal handler");
+  }
+}
+
+void install_signal_handlers(void) {
+  // check pipe is still connected
+  check_stdout_open();
+
+  // watch getppid() every PPID_ALARM_INTERVAL seconds 
+  orig_ppid = getppid();
+  if (orig_ppid <= 1) {
+    die("prematurely zombied");
+  }
+  install_signal_handler(SIGALRM, alarm_handler);
+  alarm(PPID_ALARM_INTERVAL);
+
+  // be sure to exit on SIGHUP, SIGPIPE
+  install_signal_handler(SIGHUP,  signal_handler);
+  install_signal_handler(SIGPIPE, signal_handler);
+}
+

ext/fsevent_watch/signal_handlers.h

@@ -0,0 +1,16 @@
+/**
+ * @headerfile signal_handlers.h
+ * Signal handlers to stop the zombie hordes
+ *
+ * Catch and handle signals better so that we die faster like a good meat puppet.
+ */
+
+
+#ifndef fsevent_watch_signal_handlers_h
+#define fsevent_watch_signal_handlers_h
+
+
+void install_signal_handlers(void);
+
+
+#endif // fsevent_watch_signal_handlers_h