Error out if a pre-select window is not found.

The man-page is updated to show that if the window selected using
'-p' cannot be determined with -X or -Q flags, then the command
specified will not be executed.

Fixes #28783 in savannah.

3 files changed, 17 insertions, 7 deletions

diff --git a/src/doc/screen.1 b/src/doc/screen.1
index afee22b..b580b45 100644
--- a/src/doc/screen.1
+++ b/src/doc/screen.1
@@ -293,7 +293,8 @@ Preselect a window. This is useful when you want to reattach to a
 specific window or you want to send a command via the \*Q-X\*U
 option to a specific window. As with screen's select command, \*Q-\*U
 selects the blank window. As a special case for reattach, \*Q=\*U
-brings up the windowlist on the blank window.
+brings up the windowlist on the blank window. The command will not be
+executed if the specified window could not be found.
 .TP 5
 .B \-q
 Suppress printing of error messages. In combination with \*Q-ls\*U the exit 
diff --git a/src/doc/screen.texinfo b/src/doc/screen.texinfo
index 2bdc775..5941523 100644
--- a/src/doc/screen.texinfo
+++ b/src/doc/screen.texinfo
@@ -362,7 +362,8 @@ specific window or you want to send a command via the @samp{-X}
 option to a specific window. As with screen's select command, @samp{-}
 selects the blank window. As a special case for reattach, @samp{=}
 brings up the windowlist on the blank window, while a @samp{+} will
-create new window.
+create new window. The command will not be executed if the specified
+window could not be found.
 
 @item -q
 Suppress printing of error messages. In combination with @samp{-ls} the exit 
diff --git a/src/socket.c b/src/socket.c
index 70b57db..9e90564 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -1653,7 +1653,7 @@ struct msg *mp;
     *--fc = 0;
   if (Parse(fullcmd, fc - fullcmd, args, argl) <= 0)
     {
-      /* XXX: Return some useful message back if MSG_QUERY */
+      queryflag = -1;
       return;
     }
 #ifdef MULTIUSER
@@ -1661,7 +1661,7 @@ struct msg *mp;
   if (user == 0)
     {
       Msg(0, "Unknown user %s tried to send a command!", mp->m.attach.auser);
-      /* XXX: Return some useful message back if MSG_QUERY */
+      queryflag = -1;
       return;
     }
 #else
@@ -1670,8 +1670,8 @@ struct msg *mp;
 #ifdef PASSWORD
   if (user->u_password && *user->u_password)
     {
-      Msg(0, "User %s has a password, cannot use -X option.", mp->m.attach.auser);
-      /* XXX: Return some useful message back if MSG_QUERY */
+      Msg(0, "User %s has a password, cannot use remote commands (using -Q or -X option).", mp->m.attach.auser);
+      queryflag = -1;
       return;
     }
 #endif
@@ -1692,7 +1692,15 @@ struct msg *mp;
     {
       int i = -1;
       if (strcmp(mp->m.command.preselect, "-"))
-        i = WindowByNoN(mp->m.command.preselect);
+	{
+	  i = WindowByNoN(mp->m.command.preselect);
+	  if (i < 0 || !wtab[i])
+	    {
+	      Msg(0, "Could not find pre-select window.");
+	      queryflag = -1;
+	      return;
+	    }
+	}
       fore = i >= 0 ? wtab[i] : 0;
     }
   else if (!fore)