qubes: qpass.ClipOpenURL uses xclip or xsel

Some troubleshooting why the old version never exited.  Xclip is
tricky as it leaves a child process running

Author: dncohen

qubes/qpass.ClipOpenURL

@@ -6,41 +6,69 @@
 # On dom0, create /etc/qubes-rpc/policy/qpass.ClipOpenURL.  I recommend:
 # `sudo cp /etc/qubes-rpc/policy/qubes.ClipboardPaste /etc/qubes-rpc/policy/qpass.ClipOpenURL`
 
+# Choose between xsel and xclip, by commenting one definition of
+# $clipper and $clearer
+clipper="echo install xclip or xsel to support clipboard feature"
+sleeper=""
+clearer="exit 1"
+
+command -v xclip >/dev/null 2>&1 && {
+    # xclip will allow 1 single paste (-loops 1).
+    # xclip spawned process will not terminate until pasted!
+    # clearer prevents the first xclip from exiting! TODO fix that
+    clipper="xclip -selection clipboard -loops 1"
+    sleeper=""
+    #clearer="xclip -selection clipboard"
+    clearer=""
+}
+
+command -v xsel >/dev/null 2>&1 && {
+    # xsel, after some time passes, the clearer erases the clipboard
+    clipper="xsel --input --clipboard"
+    sleeper="sleep 20"
+    clearer="xsel --clipboard -c"
+}
 
 # first line of stdin will be sent to clipboard
 read -s clip
 
 # anything else on stdin we open
 
-while read -r url
-do
+read -r url
+
     case "$url" in
 	http://*|\
 	https://*|\
 	ftp://*)
-            exec qubes-open "$url" &
+            qubes-open "$url" &
             ;;
 	*)
             echo "Invalid URL" >&2
             exit 1
             ;;
     esac
-done
 
-# write to clipboard, via `xclip`
-# we use xclip here, because xsel fails to write to clipboard ("Conversion refused")
-command -v xclip >/dev/null 2>&1 || { echo >&2 "xclip not found"; exit 1; }
+
+#echo "populating clipboard..."
+
 (cat <<EOF
 $clip
 EOF
-) | xclip -selection clipboard
+) | ($clipper &)
+
+#echo "clipper: $?"
 
+#echo "sleeping..."
 # after some time passes, clear the clipboard
-sleep 20
+$sleeper
 
 # (TODO: clear only if clipboard contents have not changed)
 
-# clear password from clipboard
-echo "" | xclip -selection clipboard
+echo "" | ($clearer)
+status=$?
+
+#echo "clearer: $?"
 
+#echo "exiting."
+exit $status
 

qvm.go

@@ -5,7 +5,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"log"
 	"os/exec"
 	"strings"
 )
@@ -74,19 +73,32 @@ func (this appvmCommand) open(group, passwd, url string) error {
 	//args = append(args, url)
 
 	cmd := exec.Command(command, args...)
-	stdin, err := cmd.StdinPipe()
+
+	// qpass.ClipOpenURL expects a password on the first line (will by
+	// copied to clipboard), followed by URLs to open (one, in our case)
+	// TODO: ensure passwd has no newlines
+	cmdIn, err := cmd.StdinPipe()
 	if err != nil {
 		return err
 	}
 	err = cmd.Start()
 	if err != nil {
 		return err
 	}
-	log.Println("HERE", passwd)
-	io.WriteString(stdin, passwd)
-	io.WriteString(stdin, "\n")
-	io.WriteString(stdin, url)
-	io.WriteString(stdin, "\n")
-	stdin.Close()
+
+	io.WriteString(cmdIn, fmt.Sprintf("%s\n%s\n", passwd, url))
+	cmdIn.Close() // explicit close, in case qpass.ClipOpenURL requires it (one version did).
+
+	// comments here as I am figuring the best way to log output of qrexec call.
+	//out, err := cmd.CombinedOutput()
+	//log.Printf("output from %s:\n%s\n", command, out)
+
+	//log.Println("WAITING", command)
+	err = cmd.Wait()
+	//log.Println("DONE", command, err)
+	if err != nil {
+		return err
+	}
+
 	return err
 }