/*-
 * Copyright (c) 2011 Doug Rabson
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * USERBOOT interface versions
 */
#define	USERBOOT_VERSION_1      1
#define	USERBOOT_VERSION_2      2
#define	USERBOOT_VERSION_3      3

/*
 * Version 4 added more generic callbacks for setting up
 * registers and descriptors. The callback structure is
 * backward compatible (new callbacks have been added at
 * the tail end).
 */
#define	USERBOOT_VERSION_4      4

/*
 * Version 5 added a callback for indicating that the guest
 * should be restarted with a different interpreter.  The callback
 * structure is still backward compatible.
 */
#define	USERBOOT_VERSION_5      5

/*
 * Exit codes from the loader
 */
#define	USERBOOT_EXIT_QUIT      1
#define	USERBOOT_EXIT_REBOOT    2

struct loader_callbacks {
	/*
	 * Console i/o
	 */

        /*
         * Wait until a key is pressed on the console and then return it
         */
	int		(*getc)(void *arg);

        /*
         * Write the character ch to the console
         */
	void		(*putc)(void *arg, int ch);

        /*
         * Return non-zero if a key can be read from the console
         */
	int		(*poll)(void *arg);

	/*
	 * Host filesystem i/o
	 */

        /*
         * Open a file in the host filesystem
         */
	int		(*open)(void *arg, const char *filename, void **h_return);

        /*
         * Close a file
         */
	int		(*close)(void *arg, void *h);

        /*
         * Return non-zero if the file is a directory
         */
	int		(*isdir)(void *arg, void *h);

        /*
         * Read size bytes from a file. The number of bytes remaining
         * in dst after reading is returned in *resid_return
         */
	int		(*read)(void *arg, void *h, void *dst, size_t size,
            size_t *resid_return);

        /*
         * Read an entry from a directory. The entry's inode number is
         * returned in *fileno_return, its type in *type_return and
         * the name length in *namelen_return. The name itself is
         * copied to the buffer name which must be at least PATH_MAX
         * in size.
         */
	int		(*readdir)(void *arg, void *h, uint32_t *fileno_return,
            uint8_t *type_return, size_t *namelen_return, char *name);

        /*
         * Seek to a location within an open file
         */
	int		(*seek)(void *arg, void *h, uint64_t offset,
            int whence);

        /*
         * Return some stat(2) related information about the file
         */
	int		(*stat)(void *arg, void *h, struct stat *stp);

	/*
	 * Disk image i/o
	 */

        /*
         * Read from a disk image at the given offset
         */
	int		(*diskread)(void *arg, int unit, uint64_t offset,
            void *dst, size_t size, size_t *resid_return);

        /*
         * Write to a disk image at the given offset
         */
	int		(*diskwrite)(void *arg, int unit, uint64_t offset,
            void *src, size_t size, size_t *resid_return);

	/*
	 * Guest virtual machine i/o
	 */

        /*
         * Copy to the guest address space
         */
	int		(*copyin)(void *arg, const void *from,
            uint64_t to, size_t size);

        /*
         * Copy from the guest address space
         */
	int		(*copyout)(void *arg, uint64_t from,
            void *to, size_t size);

        /*
         * Set a guest register value
         */
	void		(*setreg)(void *arg, int, uint64_t);

        /*
         * Set a guest MSR value
         */
	void		(*setmsr)(void *arg, int, uint64_t);

        /*
         * Set a guest CR value
         */
	void		(*setcr)(void *arg, int, uint64_t);

        /*
         * Set the guest GDT address
         */
        void            (*setgdt)(void *arg, uint64_t, size_t);

        /*
         * Transfer control to the guest at the given address
         */
	void		(*exec)(void *arg, uint64_t pc);

	/*
	 * Misc
	 */

        /*
         * Sleep for usec microseconds
         */
	void		(*delay)(void *arg, int usec);

        /*
         * Exit with the given exit code
         */
	void		(*exit)(void *arg, int v);

        /*
         * Return guest physical memory map details
         */
	void		(*getmem)(void *arg, uint64_t *lowmem,
            uint64_t *highmem);

	/*
	 * ioctl interface to the disk device
	 */
	int		(*diskioctl)(void *arg, int unit, u_long cmd,
	    void *data);

	/*
	 * Returns an environment variable in the form "name=value".
	 *
	 * If there are no more variables that need to be set in the
	 * loader environment then return NULL.
	 *
	 * 'num' is used as a handle for the callback to identify which
	 * environment variable to return next. It will begin at 0 and
	 * each invocation will add 1 to the previous value of 'num'.
	 */
	char *		(*getenv)(void *arg, int num);

	/*
	 * Version 4 additions.
	 */
	int	(*vm_set_register)(void *arg, int vcpu, int reg, uint64_t val);
	int	(*vm_set_desc)(void *arg, int vcpu, int reg, uint64_t base,
	    u_int limit, u_int access);

	/*
	 * Version 5 addition.
	 */
	void	(*swap_interpreter)(void *arg, const char *interp);
};
