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From: Simon Peter <dn.tlp@gmx.net>
Subject: Bug#306261: pppd does not properly close /dev/ppp on persist

When using the kernel PPPoE driver, pppd never
closes /dev/ppp when the link has come down.

It opens superfluous fds to the device each time it re-opens the
connection, with the unclosed ones falsely reported always ready for
data by select().

This makes pppd eat up 100% CPU time after the first persist because of
the always instantly returning select() on the unclosed fds.

The problem also occurs with the upstream version, but does not occur
when a pty/tty device is used for the ppp connection.

---
 pppd/sys-linux.c |    7 +++++++
 1 file changed, 7 insertions(+)

Index: pppd/sys-linux.c
===================================================================
--- pppd/sys-linux.c.orig
+++ pppd/sys-linux.c
@@ -453,6 +453,13 @@ int generic_establish_ppp (int fd)
     if (new_style_driver) {
 	int flags;
 
+	/* if a ppp_fd is already open, close it first */
+	if (ppp_fd > 0) {
+		close(ppp_fd);
+		remove_fd(ppp_fd);
+		ppp_fd = -1;
+	}
+
 	/* Open an instance of /dev/ppp and connect the channel to it */
 	if (ioctl(fd, PPPIOCGCHAN, &chindex) == -1) {
 	    error("Couldn't get channel number: %m");