#ifndef __VXBOOT_LOADER_H__
# define __VXBOOT_LOADER_H__

#include <stddef.h>
#include <stdint.h>
#include "vxBoot/hardware.h"

//---
// ELF struct definition
//---

/* The ELF file header.  This appears at the start of every ELF file.  */

#define EI_NIDENT (16)

typedef struct {
	uint8_t  e_ident[EI_NIDENT];	/* Magic number and other info */
	uint16_t e_type;		/* Object file type */
	uint16_t e_machine;		/* Architecture */
	uint32_t e_version;		/* Object file version */
	uint32_t e_entry;		/* Entry point virtual address */
	uint32_t e_phoff;		/* Program header table file offset */
	uint32_t e_shoff;		/* Section header table file offset */
	uint32_t e_flags;		/* Processor-specific flags */
	uint16_t e_ehsize;		/* ELF header size in bytes */
	uint16_t e_phentsize;		/* Program header table entry size */
	uint16_t e_phnum;		/* Program header table entry count */
	uint16_t e_shentsize;		/* Section header table entry size */
	uint16_t e_shnum;		/* Section header table entry count */
	uint16_t e_shstrndx;		/* Section header string table index */
} Elf32_Ehdr;

/* Fields in the e_ident array */

#define EI_MAG0		0		/* File identification byte 0 index */
#define EI_MAG1		1		/* File identification byte 1 index */
#define EI_MAG2		2		/* File identification byte 2 index */
#define EI_MAG3		3		/* File identification byte 3 index */

#define ELFMAG0		0x7f		/* Magic number byte 0 */
#define ELFMAG1		'E'		/* Magic number byte 1 */
#define ELFMAG2		'L'		/* Magic number byte 2 */
#define ELFMAG3		'F'		/* Magic number byte 3 */

/* class information */

#define EI_CLASS	4		/* File class byte index */
#define ELFCLASS32	1		/* 32-bit objects */

/* data encoding information */

#define EI_DATA		5		/* Data encoding byte index */
#define ELFDATA2MSB	2		/* 2's complement, big endian */

/* object file type */

#define ET_EXEC		2		/* Executable file */
#define ET_DYN		3		/* Shared object file */

/* architecture */
#define EM_SH		42	/* Hitachi SH */

/* ELF version */
#define EV_CURRENT	1		/* Current version */

/* Program segment header.  */

typedef struct {
	uint32_t p_type;		/* Segment type */
	uint32_t p_offset;		/* Segment file offset */
	uint32_t p_vaddr;		/* Segment virtual address */
	uint32_t p_paddr;		/* Segment physical address */
	uint32_t p_filesz;		/* Segment size in file */
	uint32_t p_memsz;		/* Segment size in memory */
	uint32_t p_flags;		/* Segment flags */
	uint32_t p_align;		/* Segment alignment */
} Elf32_Phdr;




//---
// Loader API
//---

/* kernel loading information */
struct kernel_info {
	/* kernel entry */
	uintptr_t entry;

	/* memory information */
	struct {
		struct {
			void *start;
			size_t size;
			struct {
				uintptr_t vmin;
				uintptr_t vmax;
			} elf;
		} program;
	} memory;

	/* hardware information */
	struct hwinfo hardware;
};

/* internal kernel image list */
struct ldimg {
	struct smemfs_inode * inode;
	struct ldimg *next;
};

/* loader_scan() : scan the storage memory and try to find ELF PIE file */
extern int loader_scan(void);

/* loader() : try to load a ELF PIE file */
extern int loader(struct smemfs_inode const * restrict const inode);


//---
//	Error ldpers
//---
struct ld_error_db {
	const int id;
	const char *strerror;
};
extern int loader_error(
	struct ld_error_db const * const db,
	char const * restrict const prefix,
	int const errnum
);


//---
// ELF Header ldpers
//---
enum {
	ld_header_valid			= 0,
	ld_header_size_error		= -1,
	ld_header_magic_error		= -2,
	ld_header_class_error		= -3,
	ld_header_indent_error		= -4,
	ld_header_type_error		= -5,
	ld_header_machine_error		= -6,
	ld_header_version_error		= -7,
};
/* loader_header_get() : get / check ELF header information */
extern int loader_header_get(
	struct smemfs_inode * restrict const inode,
	Elf32_Ehdr *hdr
);
/* loader_header_check() : load and check the file header validity */
extern int loader_header_check(struct smemfs_inode * restrict const inode);
extern int loader_header_error(int errnum);




//---
// ELF image ldpers
//---
enum {
	ld_image_success	= 0,
	ld_image_size_error	= -1,
	ld_image_type_error	= -2,
	ld_image_mem_error	= -3,
};
/* loader_image_load() : try to load the entier image data */
extern int loader_image_load(
	struct kernel_info * restrict const info,
	struct smemfs_inode * restrict const inode,
	Elf32_Ehdr *hdr
);
extern int loader_image_error(int const errnum);









#endif /*__VXBOOT_LOADER_H__*/