[PATCH v11 2/3] cmdline: handle EOF in cmdline_poll

[Stephen Hemminger <stephen@networkplumber.org>]

If end of file is reached on input, then cmdline_poll() will
return 1 (ie file has something); and then the cmdline_in()
call to read will return 0. With the existing code,
caller has no way to tell that end of file has been reached
 and will retry forever.

A good way to handle this is to make end of file equivalent
to the quit command. Since no more input is possible at that
point.

Fixes: 067855e651d6 ("cmdline: add polling mode")
Cc: pawelx.wodkowski@intel.com
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
Note: cmdline_poll() should not have been added back
in 2015, looks like there is no users, and no tests for this.

 lib/cmdline/cmdline.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/cmdline/cmdline.c b/lib/cmdline/cmdline.c
index e1009ba4c413..8ad0690d8533 100644
--- a/lib/cmdline/cmdline.c
+++ b/lib/cmdline/cmdline.c
@@ -197,9 +197,14 @@ cmdline_poll(struct cmdline *cl)
 		if (read_status < 0)
 			return read_status;
 
-		status = cmdline_in(cl, &c, 1);
-		if (status < 0 && cl->rdl.status != RDLINE_EXITED)
-			return status;
+		if (read_status == 0) {
+			/* end of file is implicit quit */
+			cmdline_quit(cl);
+		} else {
+			status = cmdline_in(cl, &c, 1);
+			if (status < 0 && cl->rdl.status != RDLINE_EXITED)
+				return status;
+		}
 	}
 
 	return cl->rdl.status;
-- 
2.39.0