Cpud double check args (#246)

* ds: improve the message when a service is not found

Show the service that was requested. In the case of default,
users need to see the name.

Signed-off-by: Ronald G Minnich <[email protected]>

* cmds/cpud: clean up handling of -remote

If the first arg is -remote=true or -remote,
this is a remote session. At that point, no
other settings of -remote in the args will have
any effect.

This change is necessary as pathological commands
such as
cpud -remote -d -remote=false
will cause incorrect behavior.

The command line options that can now be set from the cpu
command are:
-remote
-port9p
-d

The only one that would be sensible for a user to set
from the command line:
-d

Users wishing to get debug output can, e.g.:
cpu -d hostname command

Signed-off-by: Ronald G Minnich <[email protected]>

---------

Signed-off-by: Ronald G Minnich <[email protected]>

cmds/cpud/main_linux.go

@@ -61,7 +61,7 @@ func verbose(f string, a ...interface{}) {
 // the args to remote and the args to server are different.
 // This invocation requirement is known to the server package.
 func main() {
-	if len(os.Args) > 1 && os.Args[1] == "-remote" {
+	if len(os.Args) > 1 && (os.Args[1] == "-remote" || os.Args[1] == "-remote=true") {
 		*remote = true
 	}
 
@@ -78,8 +78,13 @@ func main() {
 			v = log.Printf
 			session.SetVerbose(verbose)
 		}
+		// If we are here, no matter what they may set, *remote must be true.
+		// sadly, cpud -d -remote=true -remote=false ... works.
+		*remote = true
 	} else {
 		flag.Parse()
+		// If we are here, no matter what they may set, *remote must be false.
+		*remote = false
 		if err := commonsetup(); err != nil {
 			log.Fatal(err)
 		}

ds/ds.go

@@ -334,7 +334,7 @@ func Lookup(query dsQuery, n int) ([]*LookupResult, error) {
 	dnssd.LookupType(ctx, service, addFn, rmvFn)
 
 	if len(responses) == 0 {
-		return nil, fmt.Errorf("dnssd found no suitable service %w", os.ErrNotExist)
+		return nil, fmt.Errorf("dnssd: %q: %w", service, os.ErrNotExist)
 	}
 
 	dsSort(query.Text, responses)