socket: switch netns for collecting sockets

All sockets should be collected in a target net name-space when the -n net
is specified.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-check.c

@@ -33,7 +33,7 @@ static int check_sock_diag(void)
 {
 	int ret;
 
-	ret = collect_sockets();
+	ret = collect_sockets(getpid());
 	if (!ret)
 		return 0;
 

cr-dump.c

@@ -1515,7 +1515,7 @@ int cr_dump_tasks(pid_t pid, const struct cr_options *opts)
 	if (mntns_collect_root(root_item->pid.real))
 		goto err;
 
-	collect_sockets();
+	collect_sockets(pid);
 
 	glob_fdset = cr_glob_fdset_open(O_DUMP);
 	if (!glob_fdset)

include/sockets.h

@@ -31,7 +31,7 @@ extern int restore_socket_opts(int sk, SkOptsEntry *soe);
 extern void show_socket_opts(SkOptsEntry *soe);
 
 extern int sk_collect_one(int ino, int family, struct socket_desc *d);
-extern int collect_sockets(void);
+extern int collect_sockets(int pid);
 extern int collect_inet_sockets(void);
 extern int collect_unix_sockets(void);
 extern int fix_external_unix_sockets(void);

sockets.c

+#include <unistd.h>
 #include <sys/socket.h>
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
@@ -10,6 +11,8 @@
 #include "files.h"
 #include "util-net.h"
 #include "sk-packet.h"
+#include "namespaces.h"
+#include "crtools.h"
 
 #ifndef NETLINK_SOCK_DIAG
 #define NETLINK_SOCK_DIAG NETLINK_INET_DIAG
@@ -170,9 +173,10 @@ static int inet6_udplite_receive_one(struct nlmsghdr *h, void *arg)
 	return inet_collect_one(h, AF_INET6, SOCK_DGRAM, IPPROTO_UDPLITE);
 }
 
-int collect_sockets(void)
+int collect_sockets(int pid)
 {
 	int err = 0, tmp;
+	int rst = -1;
 	int nl;
 	struct {
 		struct nlmsghdr hdr;
@@ -182,10 +186,18 @@ int collect_sockets(void)
 		} r;
 	} req;
 
+	if (opts.namespaces_flags & CLONE_NEWNET) {
+		pr_info("Switching to %d's net for collecting sockets\n", pid);
+
+		if (switch_ns(pid, CLONE_NEWNET, "net", &rst))
+			return -1;
+	}
+
 	nl = socket(PF_NETLINK, SOCK_RAW, NETLINK_SOCK_DIAG);
 	if (nl < 0) {
 		pr_perror("Can't create sock diag socket");
-		return -1;
+		err = -1;
+		goto out;
 	}
 
 	memset(&req, 0, sizeof(req));
@@ -261,6 +273,9 @@ int collect_sockets(void)
 		err = tmp;
 
 	close(nl);
+out:
+	if (rst > 0 && restore_ns(rst, CLONE_NEWNET) < 0)
+		err = -1;
 	return err;
 }