From 8e80a8b06fca685bdef778aae5698de03dd755a5 Mon Sep 17 00:00:00 2001
From: nonlin-lin-chaos-order-etc-etal <hypnosis.i2p@gmail.com>
Date: Wed, 10 Apr 2024 03:15:55 +0800
Subject: [PATCH] Add fcntl to actually lock pidfile on Android

---
 daemon/UnixDaemon.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/daemon/UnixDaemon.cpp b/daemon/UnixDaemon.cpp
index bf4a7662..d1eb1c39 100644
--- a/daemon/UnixDaemon.cpp
+++ b/daemon/UnixDaemon.cpp
@@ -162,12 +162,21 @@ namespace i2p
 
 #ifndef ANDROID
 				if (lockf(pidFH, F_TLOCK, 0) != 0)
+#else
+				struct flock fl;
+				fl.l_len = 0;
+				fl.l_type = F_WRLCK;
+				fl.l_whence = SEEK_SET;
+				fl.l_start = 0;
+
+				if (fcntl(pidFH, F_SETLK, &fl) != 0)
+#endif
 				{
 					LogPrint(eLogError, "Daemon: Could not lock pid file ", pidfile, ": ", strerror(errno));
 					std::cerr << "i2pd: Could not lock pid file " << pidfile << ": " << strerror(errno) << std::endl;
 					return false;
 				}
-#endif
+
 				char pid[10];
 				sprintf(pid, "%d\n", getpid());
 				ftruncate(pidFH, 0);