images: Introduce the top-level file -- inventory

Currently we store the images version in the core file. This is
bad, since core file describes a single process (or thread) and
says nothing about the images set as a whole (let alone the fact
that it's being parsed too late).

Thus introduce the inventory image file which describes the image
set the way we need (want). For now the only entry in it is the
images version. In the future it can be extended.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -675,7 +675,6 @@ static int dump_task_core(struct core_entry *core, int fd_core)
 {
 	pr_info("Dumping header ... ");
 
-	core->header.version	= HEADER_VERSION;
 	core->header.arch	= HEADER_ARCH_X86_64;
 	core->header.flags	= 0;
 
@@ -1377,6 +1376,9 @@ int cr_dump_tasks(pid_t pid, const struct cr_options *opts)
 	pr_info("Dumping process %s(pid: %d)\n", !opts->leader_only ? "group " : "", pid);
 	pr_info("========================================\n");
 
+	if (write_img_inventory())
+		goto err;
+
 	if (collect_pstree(pid, opts))
 		goto err;
 

cr-restore.c

@@ -403,11 +403,6 @@ static int check_core_header(int pid, struct task_core_entry *tc)
 	if (read_img(fd, &hdr) < 0)
 		goto out;
 
-	if (hdr.version != HEADER_VERSION) {
-		pr_err("Core version mismatch %d\n", (int)hdr.version);
-		goto out;
-	}
-
 	if (hdr.arch != HEADER_ARCH_X86_64) {
 		pr_err("Core arch mismatch %d\n", (int)hdr.arch);
 		goto out;
@@ -866,6 +861,9 @@ static int prepare_task_entries()
 
 static int restore_all_tasks(pid_t pid, struct cr_options *opts)
 {
+	if (check_img_inventory() < 0)
+		return -1;
+
 	if (prepare_task_entries() < 0)
 		return -1;
 

image.c

@@ -9,6 +9,64 @@
 #include "ipc_ns.h"
 #include "sk-inet.h"
 #include "mount.h"
+#include "protobuf.h"
+#include "protobuf/inventory.pb-c.h"
+
+int check_img_inventory(void)
+{
+	int fd, ret;
+	InventoryEntry *he;
+
+	fd = open_image_ro(CR_FD_INVENTORY);
+	if (fd < 0)
+		return -1;
+
+	ret = pb_read(fd, &he, inventory_entry);
+	close(fd);
+	if (ret < 0)
+		return ret;
+
+	ret = he->img_version;
+	inventory_entry__free_unpacked(he, NULL);
+
+	if (ret != CRTOOLS_IMAGES_V1) {
+		pr_err("Not supported images version %u\n", ret);
+		return -1;
+	}
+
+	return 0;
+}
+
+int write_img_inventory(void)
+{
+	int fd;
+	InventoryEntry he = INVENTORY_ENTRY__INIT;
+
+	pr_info("Writing image inventory (version %u)\n", CRTOOLS_IMAGES_V1);
+
+	fd = open_image(CR_FD_INVENTORY, O_DUMP);
+	if (fd < 0)
+		return -1;
+
+	he.img_version = CRTOOLS_IMAGES_V1;
+
+	if (pb_write(fd, &he, inventory_entry) < 0)
+		return -1;
+
+	close(fd);
+	return 0;
+}
+
+static void show_inventory(int fd, struct cr_options *o)
+{
+	InventoryEntry *he;
+
+	if (pb_read(fd, &he, inventory_entry) < 0)
+		return;
+
+	pr_msg("Version: %u\n", he->img_version);
+	inventory_entry__free_unpacked(he, NULL);
+}
 
 /*
  * The cr fd set is the set of files where the information
@@ -25,6 +83,7 @@
 	}
 
 struct cr_fd_desc_tmpl fdset_template[CR_FD_MAX] = {
+	FD_ENTRY(INVENTORY,	"inventory",	 show_inventory),
 	FD_ENTRY(FDINFO,	"fdinfo-%d",	 show_files),
 	FD_ENTRY(PAGES,		"pages-%d",	 show_pages),
 	FD_ENTRY(SHMEM_PAGES,	"pages-shmem-%ld", show_pages),

include/crtools.h

@@ -18,6 +18,7 @@
 #define CRIU_VERSION_MINOR	0
 
 enum {
+	CR_FD_INVENTORY,
 	/*
 	 * Task entries
 	 */
@@ -123,6 +124,9 @@ void show_ghost_file(int fd, struct cr_options *o);
 void show_fown_cont(void *p);
 void show_eventfds(int fd, struct cr_options *o);
 
+int check_img_inventory(void);
+int write_img_inventory(void);
+
 extern void print_data(unsigned long addr, unsigned char *data, size_t size);
 extern struct cr_fd_desc_tmpl fdset_template[CR_FD_MAX];
 

include/image.h

@@ -4,11 +4,18 @@
 #include "types.h"
 #include "compiler.h"
 
+/*
+ * Basic multi-file images
+ */
+
+#define CRTOOLS_IMAGES_V1	1
+
 /*
  * The magic-s below correspond to coordinates
  * of various Russian towns in the NNNNEEEE form.
  */
 
+#define INVENTORY_MAGIC		0x58313116 /* Veliky Novgorod */
 #define PSTREE_MAGIC		0x50273030 /* Kyiv */
 #define FDINFO_MAGIC		0x56213732 /* Dmitrov */
 #define PAGES_MAGIC		0x56084025 /* Vladimir */
@@ -80,12 +87,10 @@ struct page_entry {
 
 #define CR_CAP_SIZE	2
 
-#define HEADER_VERSION		1
 #define HEADER_ARCH_X86_64	1
 
 struct image_header {
-	u16	version;
-	u16	arch;
+	u32	arch;
 	u32	flags;
 } __packed;
 

protobuf/Makefile

@@ -19,6 +19,7 @@ CFLAGS		+= $(WARNINGS) $(DEFINES)
 
 LIBRARY		:= protobuf-lib.o
 
+PROTO_FILES	+= inventory.proto
 PROTO_FILES	+= fdinfo.proto
 PROTO_FILES	+= fown.proto
 PROTO_FILES	+= regfile.proto

protobuf/inventory.proto

+message inventory_entry {
+	required uint32	img_version = 1;
+}