/*
 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
 * Copyright (c) 1998,2000 Doug Rabson <dfr@freebsd.org>
 * 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.
 */

#include <sys/cdefs.h>
#include <stand.h>
#include <string.h>
#include <setjmp.h>
#include <sys/disk.h>
#include <sys/zfs_bootenv.h>

#include "bootstrap.h"
#include "disk.h"
#include "libuserboot.h"

#include "libzfs.h"

int zfs_debug = 0;
extern void abort(void);
static void userboot_zfs_probe(void);
static int userboot_zfs_found;

/* Minimum version required */
#define USERBOOT_VERSION        USERBOOT_VERSION_3

#define LOADER_PATH             "/boot/loader"
#define INTERP_MARKER           "$Interpreter:"

#define MALLOCSZ                (64*1024*1024)

struct loader_callbacks *callbacks;
void *callbacks_arg;

static jmp_buf jb;

struct arch_switch archsw;      /* MI/MD interface boundary */

static void     extract_currdev(void);
static void     check_interpreter(void);

void
delay(int usec)
{

        CALLBACK(delay, usec);
}

void
exit(int v)
{

        CALLBACK(exit, v);
        longjmp(jb, 1);
}

static void
check_interpreter(void)
{
        struct stat st;
        size_t marklen, rdsize;
        const char *guest_interp, *my_interp;
        char *buf;
        int fd;

        /*
         * If we can't stat(2) or open(2) LOADER_PATH, then we'll fail by
         * simply letting us roll on with whatever interpreter we were compiled
         * with.  This is likely not going to be an issue in reality.
         */
        buf =  NULL;
        if (stat(LOADER_PATH, &st) != 0)
                return;
        if ((fd = open(LOADER_PATH, O_RDONLY)) < 0)
                return;

        rdsize = st.st_size;
        buf = malloc(rdsize);
        if (buf == NULL)
                goto out;
        if (read(fd, buf, rdsize) < rdsize)
                goto out;

        marklen = strlen(INTERP_MARKER);
        my_interp = bootprog_interp + marklen;

        /*
         * Here we make the assumption that a loader binary without the
         * interpreter marker is a 4th one.  All loader binaries going forward
         * should have this properly specified, so our assumption should always
         * be a good one.
         */
        if ((guest_interp = memmem(buf, rdsize, INTERP_MARKER,
            marklen)) != NULL)
                guest_interp += marklen;
        else
                guest_interp = "4th";

        /*
         * The guest interpreter may not have a version of loader that
         * specifies the interpreter installed.  If that's the case, we'll
         * assume it's legacy (4th) and request a swap to that if we're
         * a Lua-userboot.
         */
        if (strcmp(my_interp, guest_interp) != 0)
                CALLBACK(swap_interpreter, guest_interp);
out:
        free(buf);
        (void) close(fd);
}

caddr_t
ptov(uintptr_t x)
{
        return ((caddr_t)x);
}

void
loader_main(struct loader_callbacks *cb, void *arg, int version, int ndisks)
{
        static char mallocbuf[MALLOCSZ];
        char *var;
        int i;

        if (version < USERBOOT_VERSION)
                abort();

        callbacks = cb;
        callbacks_arg = arg;
        userboot_disk_maxunit = ndisks;

        /*
         * initialise the heap as early as possible.  Once this is done,
         * alloc() is usable.
         */
        setheap((void *)mallocbuf,
            (void *)(mallocbuf + sizeof (mallocbuf) - 1));

        /*
         * Hook up the console
         */
        cons_probe();

        printf("\n%s", bootprog_info);
#if 0
        printf("Memory: %ld k\n", memsize() / 1024);
#endif

        /*
         * Set custom environment variables
         */
        i = 0;
        while (1) {
                var = CALLBACK(getenv, i++);
                if (var == NULL)
                        break;
                (void) putenv(var);
        }

        archsw.arch_autoload = userboot_autoload;
        archsw.arch_getdev = userboot_getdev;
        archsw.arch_copyin = userboot_copyin;
        archsw.arch_copyout = userboot_copyout;
        archsw.arch_readin = userboot_readin;
        archsw.arch_zfs_probe = userboot_zfs_probe;

        /*
         * Initialise the block cache. Set the upper limit.
         */
        bcache_init(32768, 512);
        /*
         * March through the device switch probing for things.
         */
        for (i = 0; devsw[i] != NULL; i++)
                if (devsw[i]->dv_init != NULL)
                        (void) (devsw[i]->dv_init)();

        extract_currdev();

        /*
         * Checking the interpreter isn't worth the overhead unless we
         * actually have the swap_interpreter callback, so we actually version
         * check here rather than later on.
         */
        if (version >= USERBOOT_VERSION_5)
                check_interpreter();

        if (setjmp(jb))
                return;

        interact(NULL);                 /* doesn't return */

        exit(0);
}

static void
set_currdev(const char *devname)
{

        (void) env_setenv("currdev", EV_VOLATILE, devname,
            userboot_setcurrdev, env_nounset);
        (void) env_setenv("loaddev", EV_VOLATILE, devname,
            env_noset, env_nounset);
}

/*
 * Set the 'current device' by (if possible) recovering the boot device as
 * supplied by the initial bootstrap.
 */
static void
extract_currdev(void)
{
        struct disk_devdesc dev;
        struct devdesc *dd;
        struct zfs_devdesc zdev;
        char *buf;

        if (userboot_zfs_found) {

                /* Leave the pool/root guid's unassigned */
                bzero(&zdev, sizeof (zdev));
                zdev.dd.d_dev = &zfs_dev;

                (void) zfs_fmtdev(&zdev);
                dd = &zdev.dd;
        } else if (userboot_disk_maxunit > 0) {
                dev.dd.d_dev = &userboot_disk;
                dev.dd.d_unit = 0;
                dev.d_slice = D_SLICEWILD;
                dev.d_partition = D_PARTWILD;
                /*
                 * If we cannot auto-detect the partition type then
                 * access the disk as a raw device.
                 */
                if (dev.dd.d_dev->dv_open(NULL, &dev)) {
                        dev.d_slice = D_SLICENONE;
                        dev.d_partition = D_PARTNONE;
                }
                dd = &dev.dd;
        } else {
                dev.dd.d_dev = &host_dev;
                dev.dd.d_unit = 0;
                dd = &dev.dd;
        }

        set_currdev(userboot_fmtdev(dd));

        buf = malloc(VDEV_PAD_SIZE);
        if (buf != NULL) {
                if (zfs_get_bootonce(dd, OS_BOOTONCE, buf,
                    VDEV_PAD_SIZE) == 0) {
                        printf("zfs bootonce: %s\n", buf);
                        set_currdev(buf);
                }
                free(buf);
                (void) zfs_attach_nvstore(dd);
        }
}

static void
userboot_zfs_probe(void)
{
        char devname[32];
        uint64_t pool_guid;
        int unit;

        /*
         * Open all the disks we can find and see if we can reconstruct
         * ZFS pools from them. Record if any were found.
         */
        for (unit = 0; unit < userboot_disk_maxunit; unit++) {
                (void) sprintf(devname, "disk%d:", unit);
                pool_guid = 0;
                (void) zfs_probe_dev(devname, &pool_guid);
                if (pool_guid != 0)
                        userboot_zfs_found = 1;
        }
}

COMMAND_SET(quit, "quit", "exit the loader", command_quit);

static int
command_quit(int argc, char *argv[])
{

        exit(USERBOOT_EXIT_QUIT);
        return (CMD_OK);
}

COMMAND_SET(reboot, "reboot", "reboot the system", command_reboot);

static int
command_reboot(int argc, char *argv[])
{

        exit(USERBOOT_EXIT_REBOOT);
        return (CMD_OK);
}