firemon: only use col/row when values are valid

In case stdin (or stdout/stderr) is not attached to a tty, the
ioctl can't determine the actual sizes, so keep using fallback values.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/firemon/top.c b/src/firemon/top.c
index 55a35d93d..3a79a5260 100644
--- a/src/firemon/top.c
+++ b/src/firemon/top.c
@@ -275,8 +275,10 @@ void top(void) {
                 int row = 24;
                 int col = 80;
                 if (!ioctl(STDIN_FILENO, TIOCGWINSZ, &sz)) {
-                        col = sz.ws_col;
-                        row = sz.ws_row;
+                        if (sz.ws_col > 0 && sz.ws_row > 0) {
+                                col = sz.ws_col;
+                                row = sz.ws_row;
+                        }
                 }
 
                 // start printing