img: Save crtools process IDs in inventory

On restore we'll need to know whether the root task should be
cloned in new set of namespaces. It's natural to do it by
comparing root ids with some "other-world" IDs.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

image.c

@@ -12,6 +12,7 @@
 #include "sk-packet.h"
 #include "mount.h"
 #include "net.h"
+#include "pstree.h"
 #include "protobuf.h"
 #include "protobuf/inventory.pb-c.h"
 
@@ -48,6 +49,7 @@ int write_img_inventory(void)
 {
 	int fd;
 	InventoryEntry he = INVENTORY_ENTRY__INIT;
+	struct pstree_item crt = { };
 
 	pr_info("Writing image inventory (version %u)\n", CRTOOLS_IMAGES_V1);
 
@@ -59,9 +61,16 @@ int write_img_inventory(void)
 	he.fdinfo_per_id = true;
 	he.has_fdinfo_per_id = true;
 
+	crt.pid.real = getpid();
+	if (get_task_ids(&crt))
+		return -1;
+
+	he.root_ids = crt.ids;
+
 	if (pb_write_one(fd, &he, PB_INVENTORY) < 0)
 		return -1;
 
+	xfree(crt.ids);
 	close(fd);
 	return 0;
 }

protobuf/Makefile

 PROTO_LIBRARY	:= protobuf-lib.o
 
+PROTO_FILES	+= core.proto
 PROTO_FILES	+= inventory.proto
 PROTO_FILES	+= fdinfo.proto
 PROTO_FILES	+= fown.proto
@@ -34,7 +35,6 @@ PROTO_FILES	+= ipc-sem.proto
 PROTO_FILES	+= utsns.proto
 PROTO_FILES	+= creds.proto
 PROTO_FILES	+= vma.proto
-PROTO_FILES	+= core.proto
 PROTO_FILES	+= netdev.proto
 PROTO_FILES	+= tty.proto
 PROTO_FILES	+= file-lock.proto

protobuf/inventory.proto

+import "core.proto";
+
 message inventory_entry {
 	required uint32	img_version = 1;
 	optional bool fdinfo_per_id = 2;
+	optional task_kobj_ids_entry root_ids = 3;
 }