Instead of caching the PID which opened the bpf descriptor, continuously

refresh the PID which has the descriptor open. The PID is refreshed in various
operations like ioctl(2), kevent(2) or poll(2). This produces more accurate
information about current bpf consumers. While we are here remove the bd_pcomm
member of the bpf stats structure because now that we have an accurate PID we
can lookup the via the kern.proc.pid sysctl variable. This is the trick that
NetBSD decided to use to deal with this issue.

Special care needs to be taken when MFC'ing this change, as we have made a
change to the bpf stats structure. What will end up happening is we will leave
the pcomm structure but just mark it as being un-used. This way we keep the ABI
in tact.

MFC after:	1 month
Discussed with:	Rui Paulo < rpaulo at NetBSD dot org >

1 files changed, 0 insertions, 2 deletions

diff --git a/sys/net/bpfdesc.h b/sys/net/bpfdesc.h
index 39a1340..d2cb985 100644
--- a/sys/net/bpfdesc.h
+++ b/sys/net/bpfdesc.h
@@ -95,7 +95,6 @@ struct bpf_d {
 	struct label	*bd_label;	/* MAC label for descriptor */
 	u_long		bd_fcount;	/* number of packets which matched filter */
 	pid_t		bd_pid;		/* PID which created descriptor */
-	char		bd_pcomm[MAXCOMLEN + 1];
 	int		bd_locked;	/* true if descriptor is locked */
 };
 
@@ -148,7 +147,6 @@ struct xbpf_d {
 	int		bd_bufsize;
 	pid_t		bd_pid;
 	char		bd_ifname[IFNAMSIZ];
-	char		bd_pcomm[MAXCOMLEN + 1];
 	int		bd_locked;
 };