From e62cfe621d6a3206284fddd2af95661edca7f01d Mon Sep 17 00:00:00 2001
From: Sepherosa Ziehau <sephe@dragonflybsd.org>
Date: Wed, 4 Nov 2015 10:38:13 +0800
Subject: [PATCH] socket: Dispose rights directly in soreceive(), if them are
 not wanted

Instead of leaving them to unp_gc().  This paves the way to simplify
unp_gc() and to remove filehead.

While I'm here, minor style changes.
---
 sys/kern/uipc_socket.c        | 20 ++++++++++++++++----
 test/unix/passdesc/passdesc.c | 24 +++++++++++++++++++-----
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index 7de9418108..04c08b6a60 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -1250,6 +1250,7 @@ soreceive(struct socket *so, struct sockaddr **psa, struct uio *uio,
 	struct protosw *pr = so->so_proto;
 	int moff, type = 0;
 	size_t resid, orig_resid;
+	boolean_t free_rights = FALSE;
 
 	if (uio)
 		resid = uio->uio_resid;
@@ -1395,15 +1396,22 @@ dontblock:
 				*controlp = m_copy(m, 0, m->m_len);
 			m = m->m_next;	/* XXX race */
 		} else {
+			const struct cmsghdr *cm = mtod(m, struct cmsghdr *);
+
 			if (controlp) {
 				n = sbunlinkmbuf(&so->so_rcv.sb, m, NULL);
 				if (pr->pr_domain->dom_externalize &&
-				    mtod(m, struct cmsghdr *)->cmsg_type ==
-				    SCM_RIGHTS)
-				   error = (*pr->pr_domain->dom_externalize)(m, flags);
+				    cm->cmsg_level == SOL_SOCKET &&
+				    cm->cmsg_type == SCM_RIGHTS) {
+					error = pr->pr_domain->dom_externalize
+					    (m, flags);
+				}
 				*controlp = m;
 				m = n;
 			} else {
+				if (cm->cmsg_level == SOL_SOCKET &&
+				    cm->cmsg_type == SCM_RIGHTS)
+					free_rights = TRUE;
 				m = sbunlinkmbuf(&so->so_rcv.sb, m, &free_chain);
 			}
 		}
@@ -1564,8 +1572,12 @@ release:
 	ssb_unlock(&so->so_rcv);
 done:
 	lwkt_reltoken(&so->so_rcv.ssb_token);
-	if (free_chain)
+	if (free_chain) {
+		if (free_rights && (pr->pr_flags & PR_RIGHTS) &&
+		    pr->pr_domain->dom_dispose)
+			pr->pr_domain->dom_dispose(free_chain);
 		m_freem(free_chain);
+	}
 	return (error);
 }
 
diff --git a/test/unix/passdesc/passdesc.c b/test/unix/passdesc/passdesc.c
index 42fa656ae2..c87bbff360 100644
--- a/test/unix/passdesc/passdesc.c
+++ b/test/unix/passdesc/passdesc.c
@@ -100,24 +100,29 @@ test_recv_desc(int s)
 static void
 usage(const char *cmd)
 {
-	fprintf(stderr, "%s [-d]\n", cmd);
+	fprintf(stderr, "%s [-d] [-s]\n", cmd);
 	exit(1);
 }
 
 int
 main(int argc, char *argv[])
 {
-	int s[2], fd, status, n, discard;
+	int s[2], fd, status, n, discard, skipfd;
 	int opt;
 	off_t ofs;
 
 	discard = 0;
-	while ((opt = getopt(argc, argv, "d")) != -1) {
+	skipfd = 0;
+	while ((opt = getopt(argc, argv, "ds")) != -1) {
 		switch (opt) {
 		case 'd':
 			discard = 1;
 			break;
 
+		case 's':
+			skipfd = 1;
+			break;
+
 		default:
 			usage(argv[0]);
 		}
@@ -128,10 +133,19 @@ main(int argc, char *argv[])
 
 	if (fork() == 0) {
 		close(s[0]);
-		if (!discard)
+		if (!discard && !skipfd) {
 			test_recv_desc(s[1]);
-		else
+		} else if (skipfd) {
+			int buf;
+
+			fprintf(stderr, "skipfd\n");
+			n = read(s[1], &buf, sizeof(buf));
+			if (n < 0)
+				err(1, "read failed");
+		} else {
+			fprintf(stderr, "discard msg\n");
 			sleep(5);
+		}
 		exit(0);
 	}
 	close(s[1]);
-- 
2.41.0