files: Split fdinfo in two parts

Make fdinfo_entry carry only the minimal info describing a file
descriptor -- the fd value itself, the fd type (regular file, exe
link, cwd, filemap and it will be pipes, sockets, inotifies, etc.)
and the describing file ID.

The mentioned ID will identify the type-d object, e.g. for regfiles
this ID is already generated with file-ids.c code.

The other part of this structure describes a regfile (i.e. a file
opened with open syscall). I put this new entry at the end of the
fdinfo_entry just to make the patching simpler. Soon this entry
will be dumped into its own file.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

include/image.h

@@ -44,16 +44,21 @@ enum fd_types {
 #define PAGE_RSS	1
 #define PAGE_ANON	2
 
-struct fdinfo_entry {
-	u8	type;
-	u16	len;
-	u16	flags;
-	u64	pos;
-	u64	addr;
+struct reg_file_entry {
 	u32	id;
+	u16	flags;
+	u16	len;
+	u64	pos;
 	u8	name[0];
 } __packed;
 
+struct fdinfo_entry {
+	u64	addr;
+	u8	type;
+	u32	id;
+	struct reg_file_entry rfe;
+} __packed;
+
 #define fd_is_special(fe)		\
 	(((fe)->type == FDINFO_MAP) ||	\
 	 ((fe)->type == FDINFO_CWD) ||	\