Implement daemon() using fork() for OSX

src/nghttpd.cc

@@ -435,7 +435,7 @@ int main(int argc, char **argv) {
 #ifdef __sgi
     if (daemon(0, 0, 0, 0) == -1) {
 #else
-    if (daemon(0, 0) == -1) {
+    if (util::daemonize(0, 0) == -1) {
 #endif
       perror("daemon");
       exit(EXIT_FAILURE);

src/shrpx.cc

@@ -1148,7 +1148,7 @@ int call_daemon() {
     return 0;
   }
 #  endif // HAVE_LIBSYSTEMD
-  return daemon(0, 0);
+  return util::daemonize(0, 0);
 #endif   // !__sgi
 }
 } // namespace

src/util.cc

@@ -1542,6 +1542,46 @@ std::mt19937 make_mt19937() {
   return std::mt19937(rd());
 }
 
+int daemonize(int nochdir, int noclose) {
+#if defined(__APPLE__)
+  pid_t pid;
+  pid = fork();
+  if (pid == -1) {
+    return -1;
+  } else if (pid > 0) {
+    _exit(EXIT_SUCCESS);
+  }
+  if (setsid() == -1) {
+    return -1;
+  }
+  pid = fork();
+  if (pid == -1) {
+    return -1;
+  } else if (pid > 0) {
+    _exit(EXIT_SUCCESS);
+  }
+  if (nochdir == 0) {
+    if (chdir("/") == -1) {
+      return -1;
+    }
+  }
+  if (noclose == 0) {
+    if (freopen("/dev/null", "r", stdin) == nullptr) {
+      return -1;
+    }
+    if (freopen("/dev/null", "w", stdout) == nullptr) {
+      return -1;
+    }
+    if (freopen("/dev/null", "w", stderr) == nullptr) {
+      return -1;
+    }
+  }
+  return 0;
+#else  // !defined(__APPLE__)
+  return daemon(nochdir, noclose);
+#endif // !defined(__APPLE__)
+}
+
 } // namespace util
 
 } // namespace nghttp2

src/util.h

@@ -772,6 +772,10 @@ StringRef extract_host(const StringRef &hostport);
 // Returns new std::mt19937 object.
 std::mt19937 make_mt19937();
 
+// daemonize calls daemon(3).  If __APPLE__ is defined, it implements
+// daemon() using fork().
+int daemonize(int nochdir, int noclose);
+
 } // namespace util
 
 } // namespace nghttp2