From d6a59e33c7c197d0c61abe7f4ae5666c95535b89 Mon Sep 17 00:00:00 2001
From: Jacob Lifshay <programmerjake@gmail.com>
Date: Tue, 19 Apr 2022 22:33:15 -0700
Subject: [PATCH] set up for use by systemd

---
 .gitignore           |  1 +
 program-fpga.py      | 24 ++++++++++++++++--------
 program-fpga.service | 13 +++++++++++++
 program-fpga.socket  |  8 ++++++++
 4 files changed, 38 insertions(+), 8 deletions(-)
 create mode 100644 program-fpga.service
 create mode 100644 program-fpga.socket

diff --git a/.gitignore b/.gitignore
index 4196ccb..a34da97 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 .gitlab-runner-ccache
+.vscode
diff --git a/program-fpga.py b/program-fpga.py
index 0334601..52f8cae 100755
--- a/program-fpga.py
+++ b/program-fpga.py
@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-import io
 import pty
 import socket
 import socketserver
@@ -79,16 +78,25 @@ class RequestHandler(socketserver.BaseRequestHandler):
         send_chunk(self.request, str(status).encode())
 
 
-if sys.argv[1:] == ["--daemon"]:
-    try:
-        os.unlink(SOCKET_PATH)
-    except FileNotFoundError:
-        pass
+if sys.argv[1] == "--daemon":
+    if len(sys.argv) > 2:
+        assert len(sys.argv) == 3, "invalid command line"
+        assert sys.argv[2].isdigit(), "invalid listening fd"
+        listen_socket = socket.socket(fileno=int(sys.argv[2]))
+    else:
+        listen_socket = None
+        try:
+            os.unlink(SOCKET_PATH)
+        except FileNotFoundError:
+            pass
     fd = os.open("/dev/null", os.O_RDONLY)
     os.dup2(fd, sys.stdin.fileno())
     os.close(fd)
-    with socketserver.UnixStreamServer(SOCKET_PATH, RequestHandler) as server:
-        server.allow_reuse_address = True
+    with socketserver.UnixStreamServer(
+            SOCKET_PATH, RequestHandler,
+            bind_and_activate=listen_socket is None) as server:
+        if listen_socket is not None:
+            server.socket = listen_socket
         server.serve_forever()
 else:
     assert len(sys.argv) == 4, "invalid command line"
diff --git a/program-fpga.service b/program-fpga.service
new file mode 100644
index 0000000..ff140a6
--- /dev/null
+++ b/program-fpga.service
@@ -0,0 +1,13 @@
+[Unit]
+Description=Service for Programming the FPGA
+Requires=program-fpga.socket
+
+[Service]
+Type=simple
+ExecStart=bash -ic 'exec program-fpga.py --daemon 3'
+WorkingDirectory=%S/program-fpga
+StateDirectory=program-fpga
+
+[Install]
+Also=program-fpga.socket
+WantedBy=multi-user.target
\ No newline at end of file
diff --git a/program-fpga.socket b/program-fpga.socket
new file mode 100644
index 0000000..ca1950b
--- /dev/null
+++ b/program-fpga.socket
@@ -0,0 +1,8 @@
+[Unit]
+Description=Socket for Programming the FPGA
+
+[Socket]
+ListenStream=%t/program-fpga.sock
+
+[Install]
+WantedBy=sockets.target
-- 
2.30.2