refactor: pass procfs location to docker_tls_args on command line

...rather than via an env var. This is cleaner.

prog/docker_tls_args/main.go

@@ -1,6 +1,5 @@
 // docker_tls_args: find the docker daemon's tls args
-// This reimplements pgrep, because pgrep will only look in /proc, but not in
-// $PROCFS.
+// This reimplements pgrep, because pgrep will only look in /proc.
 package main
 
 import (
@@ -14,9 +13,9 @@ import (
 )
 
 func main() {
-	procRoot := os.Getenv("PROCFS")
-	if procRoot == "" {
-		procRoot = "/proc"
+	procRoot := "/proc"
+	if len(os.Args) > 1 {
+		procRoot = os.Args[1]
 	}
 
 	dirEntries, err := ioutil.ReadDir(procRoot)

weave

@@ -1435,7 +1435,7 @@ proxy_args() {
     proxy_parse_args "$@"
 
     if [ -z "$PROXY_TLS_ENABLED" -a -z "$PROXY_TLS_DETECTION_DISABLED" ] && command_exists docker_tls_args ; then
-        if ! DOCKER_TLS_ARGS=$(docker_tls_args) ; then
+        if ! DOCKER_TLS_ARGS=$(docker_tls_args ${PROCFS:-/proc}) ; then
             echo "Unable to auto-detect proxy TLS configuration; you must launch the proxy with" >&2
             echo "'weave launch-proxy' and supply '--no-detect-tls' or TLS options." >&2
             exit 1