From: Dmitry V. Levin <ldv@altlinux.org>
Date: Wed, 15 Nov 2017 15:30:49 +0000 (+0000)
Subject: netlink: print descriptor attributes using printfd
X-Git-Tag: v4.21~317
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=300d9f1fee6fbd7090c605f97d82440d8a5a9b2a;p=strace

netlink: print descriptor attributes using printfd

* nlattr.h (DECL_NLA(fd)): New prototype.
* nlattr.c (decode_nla_fd): New function.
* rtnl_link.c (ifla_xdp_nla_decoders) <IFLA_XDP_FD>: Use it.
(ifinfomsg_nla_decoders) <IFLA_NET_NS_FD>: Likewise.
* rtnl_nsid.c (rtgenmsg_nla_decoders) <NETNSA_FD>: Likewise.
* NEWS: Mention this.
---

diff --git a/NEWS b/NEWS
index c5150f04..3e95029e 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,9 @@
 Noteworthy changes in release ?.?? (????-??-??)
 ===============================================
 
+* Improvements
+  * Implemented decoding of netlink descriptor attributes as file descriptors.
+
 Noteworthy changes in release 4.20 (2017-11-13)
 ===============================================
 
diff --git a/nlattr.c b/nlattr.c
index 6f35b994..ac430f4f 100644
--- a/nlattr.c
+++ b/nlattr.c
@@ -207,6 +207,22 @@ decode_nla_meminfo(struct tcb *const tcp,
 	return true;
 }
 
+bool
+decode_nla_fd(struct tcb *const tcp,
+	      const kernel_ulong_t addr,
+	      const unsigned int len,
+	      const void *const opaque_data)
+{
+	int fd;
+
+	if (len < sizeof(fd))
+		return false;
+	else if (!umove_or_printaddr(tcp, addr, &fd))
+		printfd(tcp, fd);
+
+	return true;
+}
+
 bool
 decode_nla_ifindex(struct tcb *const tcp,
 	       const kernel_ulong_t addr,
diff --git a/nlattr.h b/nlattr.h
index 323f1d6b..00cbfd52 100644
--- a/nlattr.h
+++ b/nlattr.h
@@ -60,6 +60,7 @@ DECL_NLA(be16);
 DECL_NLA(be64);
 DECL_NLA(str);
 DECL_NLA(strn);
+DECL_NLA(fd);
 DECL_NLA(ifindex);
 DECL_NLA(meminfo);
 DECL_NLA(rt_class);
diff --git a/rtnl_link.c b/rtnl_link.c
index 13e56e0d..46d78b6c 100644
--- a/rtnl_link.c
+++ b/rtnl_link.c
@@ -356,7 +356,7 @@ decode_ifla_xdp_flags(struct tcb *const tcp,
 }
 
 static const nla_decoder_t ifla_xdp_nla_decoders[] = {
-	[IFLA_XDP_FD]		= decode_nla_s32,
+	[IFLA_XDP_FD]		= decode_nla_fd,
 	[IFLA_XDP_ATTACHED]	= decode_nla_u8,
 	[IFLA_XDP_FLAGS]	= decode_ifla_xdp_flags,
 	[IFLA_XDP_PROG_ID]	= decode_nla_u32
@@ -403,7 +403,7 @@ static const nla_decoder_t ifinfomsg_nla_decoders[] = {
 	[IFLA_PORT_SELF]	= decode_ifla_port,
 	[IFLA_AF_SPEC]		= NULL, /* unimplemented */
 	[IFLA_GROUP]		= decode_nla_u32,
-	[IFLA_NET_NS_FD]	= decode_nla_u32,
+	[IFLA_NET_NS_FD]	= decode_nla_fd,
 	[IFLA_EXT_MASK]		= decode_nla_u32,
 	[IFLA_PROMISCUITY]	= decode_nla_u32,
 	[IFLA_NUM_TX_QUEUES]	= decode_nla_u32,
diff --git a/rtnl_nsid.c b/rtnl_nsid.c
index 51ce37b4..cf8cc995 100644
--- a/rtnl_nsid.c
+++ b/rtnl_nsid.c
@@ -40,7 +40,7 @@
 static const nla_decoder_t rtgenmsg_nla_decoders[] = {
 	[NETNSA_NSID]	= decode_nla_s32,
 	[NETNSA_PID]	= decode_nla_u32,
-	[NETNSA_FD]	= decode_nla_u32
+	[NETNSA_FD]	= decode_nla_fd
 };
 
 DECL_NETLINK_ROUTE_DECODER(decode_rtgenmsg)