From 282f4256e0b978545cde80e849e6ec09b3d04a8e Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Mon, 26 Jun 2017 03:22:14 +0000
Subject: [PATCH] artiq_pcap: atomically replace pcap file.

Otherwise this segfaults Wireshark (?!).
---
 artiq/frontend/artiq_pcap.py | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/artiq/frontend/artiq_pcap.py b/artiq/frontend/artiq_pcap.py
index 8ec01fc00..66b39683b 100644
--- a/artiq/frontend/artiq_pcap.py
+++ b/artiq/frontend/artiq_pcap.py
@@ -5,6 +5,7 @@
 #    use # setcap cap_net_raw+eip /usr/sbin/tcpdump
 
 import argparse
+import os
 import subprocess
 
 from artiq.tools import verbosity_args, init_logger, logger, SSHClient
@@ -27,7 +28,7 @@ def get_argparser():
                         help="Location to retrieve the pcap file into")
 
     parser.add_argument("command", metavar="COMMAND",
-                        type=str, default=[], nargs="+",
+                        type=str, default=[], nargs=argparse.REMAINDER,
                         help="command to execute while capturing")
 
     return parser
@@ -52,5 +53,6 @@ def main():
 
     tcpdump.close()
     sftp.get("{tmp}/trace.pcap".format(tmp=client.tmp),
-             args.file)
+             args.file + ".new")
+    os.rename(args.file + ".new", args.file)
     logger.info("Pcap file {file} retrieved".format(file=args.file))