dump: get a file descriptor on procfs from parasite

This proc will be used for dumping zombies from pidns.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -60,6 +60,7 @@
 #endif
 
 static char loc_buf[PAGE_SIZE];
+static int pidns_proc = -1;
 
 void free_mappings(struct list_head *vma_area_list)
 {
@@ -1391,13 +1392,21 @@ static int dump_one_task(struct pstree_item *item)
 		goto err;
 	}
 
+	ret = -1;
 	parasite_ctl = parasite_infect_seized(pid, &vma_area_list);
 	if (!parasite_ctl) {
-		ret = -1;
 		pr_err("Can't infect (pid: %d) with parasite\n", pid);
 		goto err;
 	}
 
+	if (opts.namespaces_flags & CLONE_NEWPID && pidns_proc < 0) {
+		pidns_proc = parasite_get_proc_fd_seized(parasite_ctl);
+		if (pidns_proc < 0) {
+			pr_err("Can't get proc fd (pid: %d)\n", pid);
+			goto err_cure_fdset;
+		}
+	}
+
 	ret = parasite_dump_misc_seized(parasite_ctl, &misc);
 	if (ret) {
 		pr_err("Can't dump misc (pid: %d)\n", pid);
@@ -1557,5 +1566,7 @@ err:
 			ret ? TASK_ALIVE : opts->final_state);
 	free_pstree(root_item);
 
+	close_safe(&pidns_proc);
+
 	return ret;
 }