netns: use read built-in instead of ncat hack for dmesg

This misses lines that are greater than 128 bytes -- read returns
-EINVAL -- but the lines we care about anyway are less than that, so we
simply keep looping and skip the bad reads when this happens. Not ideal,
but probably the best we can do in pure bash.

And, importantly, it's much better than streaming this over a TCP
socket, which was an even uglier hack.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 2 insertions, 4 deletions

diff --git a/src/tests/netns.sh b/src/tests/netns.sh
index 2d77479..1aa741d 100755
--- a/src/tests/netns.sh
+++ b/src/tests/netns.sh
@@ -412,12 +412,10 @@ ip0 link del wg0
 ! n0 wg show doesnotexist || false
 
 declare -A objects
-n0 ncat -i 1 -l -p 1111 < /dev/kmsg &
-waitncattcp $netns0
-while read -r line; do
+while read -t 0.1 -r line 2>/dev/null || [[ $? -ne 142 ]]; do
 	[[ $line =~ .*(wg[0-9]+:\ [A-Z][a-z]+\ [0-9]+)\ .*(created|destroyed).* ]] || continue
 	objects["${BASH_REMATCH[1]}"]+="${BASH_REMATCH[2]}"
-done < <(n0 ncat -i 1 127.0.0.1 1111)
+done < /dev/kmsg
 alldeleted=1
 for object in "${!objects[@]}"; do
 	if [[ ${objects["$object"]} != *createddestroyed ]]; then