Clang diagnostics

Based on clang diagnostics:

1. lib/nl.c: recvmsgs(): nla filling with zeros commented.
2. lib/route/classid.c: & lib/route/pktloc.c:
   remove zero-filling of struct stat
3. lib/route/qdisc/htb.c: Fix htb_qdisc_msg_fill(): fix zero-filling
4. ematch/container.c: container_parse:
   commented why only 4 bytes are copied
   len marked as unused to eliminate compiler warning

5 files changed, 19 insertions, 7 deletions

diff --git a/lib/nl.c b/lib/nl.c
index 5b37c2a..2fa741f 100644
--- a/lib/nl.c
+++ b/lib/nl.c
@@ -540,6 +540,12 @@ static int recvmsgs(struct nl_sock *sk, struct nl_cb *cb)
 	int n, err = 0, multipart = 0, interrupted = 0, nrecv = 0;
 	unsigned char *buf = NULL;
 	struct nlmsghdr *hdr;
+
+	/*
+	nla is passed on to not only to nl_recv() but may also be passed
+	to a function pointer provided by the caller which may or may not
+	initialize the variable. Thomas Graf.
+	*/
 	struct sockaddr_nl nla = {0};
 	struct nl_msg *msg = NULL;
 	struct ucred *creds = NULL;
diff --git a/lib/route/classid.c b/lib/route/classid.c
index a128773..87025a0 100644
--- a/lib/route/classid.c
+++ b/lib/route/classid.c
@@ -311,7 +311,7 @@ static int classid_map_add(uint32_t classid, const char *name)
 int rtnl_tc_read_classid_file(void)
 {
 	static time_t last_read;
-	struct stat st = {0};
+	struct stat st;
 	char buf[256], *path;
 	FILE *fd;
 	int err;
diff --git a/lib/route/cls/ematch/container.c b/lib/route/cls/ematch/container.c
index ddbdce0..6d73ab6 100644
--- a/lib/route/cls/ematch/container.c
+++ b/lib/route/cls/ematch/container.c
@@ -14,8 +14,14 @@
 #include <netlink/netlink.h>
 #include <netlink/route/cls/ematch.h>
 
-static int container_parse(struct rtnl_ematch *e, void *data, size_t len)
+static int container_parse(struct rtnl_ematch *e, void *data, size_t len __attribute__((unused)))
 {
+	/*
+	The kernel may provide more than 4 bytes of data in the future and we want
+	older libnl versions to be ok with that. We want interfaces to be growable
+	so we only ever enforce a minimum data length and copy as much as we are
+	aware of. Thomas Graf.
+	*/
 	memcpy(e->e_data, data, sizeof(uint32_t));
 
 	return 0;
diff --git a/lib/route/pktloc.c b/lib/route/pktloc.c
index e7dffe5..70d552b 100644
--- a/lib/route/pktloc.c
+++ b/lib/route/pktloc.c
@@ -90,7 +90,7 @@ static int read_pktlocs(void)
 	YY_BUFFER_STATE buf = NULL;
 	yyscan_t scanner = NULL;
 	static time_t last_read;
-	struct stat st = {0};
+	struct stat st;
 	char *path;
 	int i, err;
 	FILE *fd;
diff --git a/lib/route/qdisc/htb.c b/lib/route/qdisc/htb.c
index 4298580..9fb0bf6 100644
--- a/lib/route/qdisc/htb.c
+++ b/lib/route/qdisc/htb.c
@@ -190,10 +190,10 @@ static int htb_qdisc_msg_fill(struct rtnl_tc *tc, void *data,
 			      struct nl_msg *msg)
 {
 	struct rtnl_htb_qdisc *htb = data;
-	struct tc_htb_glob opts = {0};
-
-	opts.version = TC_HTB_PROTOVER;
-	opts.rate2quantum = 10;
+	struct tc_htb_glob opts = {
+        	.version = TC_HTB_PROTOVER,
+	        .rate2quantum = 10,
+        };
 
 	if (htb) {
 		if (htb->qh_mask & SCH_HTB_HAS_RATE2QUANTUM)