loader: zfs should support bootonce an nextboot

[FreeBSD/FreeBSD.git] / stand / efi / loader / main.c

/*-
 * Copyright (c) 2008-2010 Rui Paulo
 * Copyright (c) 2006 Marcel Moolenaar
 * All rights reserved.
 *
 * Copyright (c) 2016-2019 Netflix, Inc. written by M. Warner Losh
 * 
 * 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 ``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 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>
__FBSDID("$FreeBSD$");

#include <stand.h>

#include <sys/disk.h>
#include <sys/param.h>
#include <sys/reboot.h>
#include <sys/boot.h>
#include <sys/zfs_bootenv.h>
#include <paths.h>
#include <stdint.h>
#include <string.h>
#include <setjmp.h>
#include <disk.h>

#include <efi.h>
#include <efilib.h>
#include <efichar.h>

#include <uuid.h>

#include <bootstrap.h>
#include <smbios.h>

#include "efizfs.h"

#include "loader_efi.h"

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

EFI_GUID acpi = ACPI_TABLE_GUID;
EFI_GUID acpi20 = ACPI_20_TABLE_GUID;
EFI_GUID devid = DEVICE_PATH_PROTOCOL;
EFI_GUID imgid = LOADED_IMAGE_PROTOCOL;
EFI_GUID mps = MPS_TABLE_GUID;
EFI_GUID netid = EFI_SIMPLE_NETWORK_PROTOCOL;
EFI_GUID smbios = SMBIOS_TABLE_GUID;
EFI_GUID smbios3 = SMBIOS3_TABLE_GUID;
EFI_GUID dxe = DXE_SERVICES_TABLE_GUID;
EFI_GUID hoblist = HOB_LIST_TABLE_GUID;
EFI_GUID lzmadecomp = LZMA_DECOMPRESSION_GUID;
EFI_GUID mpcore = ARM_MP_CORE_INFO_TABLE_GUID;
EFI_GUID esrt = ESRT_TABLE_GUID;
EFI_GUID memtype = MEMORY_TYPE_INFORMATION_TABLE_GUID;
EFI_GUID debugimg = DEBUG_IMAGE_INFO_TABLE_GUID;
EFI_GUID fdtdtb = FDT_TABLE_GUID;
EFI_GUID inputid = SIMPLE_TEXT_INPUT_PROTOCOL;

/*
 * Number of seconds to wait for a keystroke before exiting with failure
 * in the event no currdev is found. -2 means always break, -1 means
 * never break, 0 means poll once and then reboot, > 0 means wait for
 * that many seconds. "fail_timeout" can be set in the environment as
 * well.
 */
static int fail_timeout = 5;

/*
 * Current boot variable
 */
UINT16 boot_current;

/*
 * Image that we booted from.
 */
EFI_LOADED_IMAGE *boot_img;

static bool
has_keyboard(void)
{
        EFI_STATUS status;
        EFI_DEVICE_PATH *path;
        EFI_HANDLE *hin, *hin_end, *walker;
        UINTN sz;
        bool retval = false;

        /*
         * Find all the handles that support the SIMPLE_TEXT_INPUT_PROTOCOL and
         * do the typical dance to get the right sized buffer.
         */
        sz = 0;
        hin = NULL;
        status = BS->LocateHandle(ByProtocol, &inputid, 0, &sz, 0);
        if (status == EFI_BUFFER_TOO_SMALL) {
                hin = (EFI_HANDLE *)malloc(sz);
                status = BS->LocateHandle(ByProtocol, &inputid, 0, &sz,
                    hin);
                if (EFI_ERROR(status))
                        free(hin);
        }
        if (EFI_ERROR(status))
                return retval;

        /*
         * Look at each of the handles. If it supports the device path protocol,
         * use it to get the device path for this handle. Then see if that
         * device path matches either the USB device path for keyboards or the
         * legacy device path for keyboards.
         */
        hin_end = &hin[sz / sizeof(*hin)];
        for (walker = hin; walker < hin_end; walker++) {
                status = OpenProtocolByHandle(*walker, &devid, (void **)&path);
                if (EFI_ERROR(status))
                        continue;

                while (!IsDevicePathEnd(path)) {
                        /*
                         * Check for the ACPI keyboard node. All PNP3xx nodes
                         * are keyboards of different flavors. Note: It is
                         * unclear of there's always a keyboard node when
                         * there's a keyboard controller, or if there's only one
                         * when a keyboard is detected at boot.
                         */
                        if (DevicePathType(path) == ACPI_DEVICE_PATH &&
                            (DevicePathSubType(path) == ACPI_DP ||
                                DevicePathSubType(path) == ACPI_EXTENDED_DP)) {
                                ACPI_HID_DEVICE_PATH  *acpi;

                                acpi = (ACPI_HID_DEVICE_PATH *)(void *)path;
                                if ((EISA_ID_TO_NUM(acpi->HID) & 0xff00) == 0x300 &&
                                    (acpi->HID & 0xffff) == PNP_EISA_ID_CONST) {
                                        retval = true;
                                        goto out;
                                }
                        /*
                         * Check for USB keyboard node, if present. Unlike a
                         * PS/2 keyboard, these definitely only appear when
                         * connected to the system.
                         */
                        } else if (DevicePathType(path) == MESSAGING_DEVICE_PATH &&
                            DevicePathSubType(path) == MSG_USB_CLASS_DP) {
                                USB_CLASS_DEVICE_PATH *usb;

                                usb = (USB_CLASS_DEVICE_PATH *)(void *)path;
                                if (usb->DeviceClass == 3 && /* HID */
                                    usb->DeviceSubClass == 1 && /* Boot devices */
                                    usb->DeviceProtocol == 1) { /* Boot keyboards */
                                        retval = true;
                                        goto out;
                                }
                        }
                        path = NextDevicePathNode(path);
                }
        }
out:
        free(hin);
        return retval;
}

static void
set_currdev(const char *devname)
{

        /*
         * Don't execute hooks here; we may need to try setting these more than
         * once here if we're probing for the ZFS pool we're supposed to boot.
         * The currdev hook is intended to just validate user input anyways,
         * while the loaddev hook makes it immutable once we've determined what
         * the proper currdev is.
         */
        env_setenv("currdev", EV_VOLATILE | EV_NOHOOK, devname, efi_setcurrdev,
            env_nounset);
        env_setenv("loaddev", EV_VOLATILE | EV_NOHOOK, devname, env_noset,
            env_nounset);
}

static void
set_currdev_devdesc(struct devdesc *currdev)
{
        const char *devname;

        devname = efi_fmtdev(currdev);
        printf("Setting currdev to %s\n", devname);
        set_currdev(devname);
}

static void
set_currdev_devsw(struct devsw *dev, int unit)
{
        struct devdesc currdev;

        currdev.d_dev = dev;
        currdev.d_unit = unit;

        set_currdev_devdesc(&currdev);
}

static void
set_currdev_pdinfo(pdinfo_t *dp)
{

        /*
         * Disks are special: they have partitions. if the parent
         * pointer is non-null, we're a partition not a full disk
         * and we need to adjust currdev appropriately.
         */
        if (dp->pd_devsw->dv_type == DEVT_DISK) {
                struct disk_devdesc currdev;

                currdev.dd.d_dev = dp->pd_devsw;
                if (dp->pd_parent == NULL) {
                        currdev.dd.d_unit = dp->pd_unit;
                        currdev.d_slice = D_SLICENONE;
                        currdev.d_partition = D_PARTNONE;
                } else {
                        currdev.dd.d_unit = dp->pd_parent->pd_unit;
                        currdev.d_slice = dp->pd_unit;
                        currdev.d_partition = D_PARTISGPT; /* XXX Assumes GPT */
                }
                set_currdev_devdesc((struct devdesc *)&currdev);
        } else {
                set_currdev_devsw(dp->pd_devsw, dp->pd_unit);
        }
}

static bool
sanity_check_currdev(void)
{
        struct stat st;

        return (stat(PATH_DEFAULTS_LOADER_CONF, &st) == 0 ||
#ifdef PATH_BOOTABLE_TOKEN
            stat(PATH_BOOTABLE_TOKEN, &st) == 0 || /* non-standard layout */
#endif
            stat(PATH_KERNEL, &st) == 0);
}

#ifdef EFI_ZFS_BOOT
static bool
probe_zfs_currdev(uint64_t guid)
{
        char *devname;
        struct zfs_devdesc currdev;
        char *buf = NULL;
        bool rv;

        currdev.dd.d_dev = &zfs_dev;
        currdev.dd.d_unit = 0;
        currdev.pool_guid = guid;
        currdev.root_guid = 0;
        set_currdev_devdesc((struct devdesc *)&currdev);
        devname = efi_fmtdev(&currdev);
        init_zfs_boot_options(devname);

        rv = sanity_check_currdev();
        if (rv) {
                buf = malloc(VDEV_PAD_SIZE);
                if (buf != NULL) {
                        if (zfs_get_bootonce(&currdev, OS_BOOTONCE, buf,
                            VDEV_PAD_SIZE) == 0) {
                                printf("zfs bootonce: %s\n", buf);
                                set_currdev(buf);
                                setenv("zfs-bootonce", buf, 1);
                        }
                        free(buf);
                        (void) zfs_attach_nvstore(&currdev);
                }
        }
        return (rv);
}
#endif

static bool
try_as_currdev(pdinfo_t *hd, pdinfo_t *pp)
{
        uint64_t guid;

#ifdef EFI_ZFS_BOOT
        /*
         * If there's a zpool on this device, try it as a ZFS
         * filesystem, which has somewhat different setup than all
         * other types of fs due to imperfect loader integration.
         * This all stems from ZFS being both a device (zpool) and
         * a filesystem, plus the boot env feature.
         */
        if (efizfs_get_guid_by_handle(pp->pd_handle, &guid))
                return (probe_zfs_currdev(guid));
#endif
        /*
         * All other filesystems just need the pdinfo
         * initialized in the standard way.
         */
        set_currdev_pdinfo(pp);
        return (sanity_check_currdev());
}

/*
 * Sometimes we get filenames that are all upper case
 * and/or have backslashes in them. Filter all this out
 * if it looks like we need to do so.
 */
static void
fix_dosisms(char *p)
{
        while (*p) {
                if (isupper(*p))
                        *p = tolower(*p);
                else if (*p == '\\')
                        *p = '/';
                p++;
        }
}

#define SIZE(dp, edp) (size_t)((intptr_t)(void *)edp - (intptr_t)(void *)dp)

enum { BOOT_INFO_OK = 0, BAD_CHOICE = 1, NOT_SPECIFIC = 2  };
static int
match_boot_info(char *boot_info, size_t bisz)
{
        uint32_t attr;
        uint16_t fplen;
        size_t len;
        char *walker, *ep;
        EFI_DEVICE_PATH *dp, *edp, *first_dp, *last_dp;
        pdinfo_t *pp;
        CHAR16 *descr;
        char *kernel = NULL;
        FILEPATH_DEVICE_PATH  *fp;
        struct stat st;
        CHAR16 *text;

        /*
         * FreeBSD encodes it's boot loading path into the boot loader
         * BootXXXX variable. We look for the last one in the path
         * and use that to load the kernel. However, if we only fine
         * one DEVICE_PATH, then there's nothing specific and we should
         * fall back.
         *
         * In an ideal world, we'd look at the image handle we were
         * passed, match up with the loader we are and then return the
         * next one in the path. This would be most flexible and cover
         * many chain booting scenarios where you need to use this
         * boot loader to get to the next boot loader. However, that
         * doesn't work. We rarely have the path to the image booted
         * (just the device) so we can't count on that. So, we do the
         * enxt best thing, we look through the device path(s) passed
         * in the BootXXXX varaible. If there's only one, we return
         * NOT_SPECIFIC. Otherwise, we look at the last one and try to
         * load that. If we can, we return BOOT_INFO_OK. Otherwise we
         * return BAD_CHOICE for the caller to sort out.
         */
        if (bisz < sizeof(attr) + sizeof(fplen) + sizeof(CHAR16))
                return NOT_SPECIFIC;
        walker = boot_info;
        ep = walker + bisz;
        memcpy(&attr, walker, sizeof(attr));
        walker += sizeof(attr);
        memcpy(&fplen, walker, sizeof(fplen));
        walker += sizeof(fplen);
        descr = (CHAR16 *)(intptr_t)walker;
        len = ucs2len(descr);
        walker += (len + 1) * sizeof(CHAR16);
        last_dp = first_dp = dp = (EFI_DEVICE_PATH *)walker;
        edp = (EFI_DEVICE_PATH *)(walker + fplen);
        if ((char *)edp > ep)
                return NOT_SPECIFIC;
        while (dp < edp && SIZE(dp, edp) > sizeof(EFI_DEVICE_PATH)) {
                text = efi_devpath_name(dp);
                if (text != NULL) {
                        printf("   BootInfo Path: %S\n", text);
                        efi_free_devpath_name(text);
                }
                last_dp = dp;
                dp = (EFI_DEVICE_PATH *)((char *)dp + efi_devpath_length(dp));
        }

        /*
         * If there's only one item in the list, then nothing was
         * specified. Or if the last path doesn't have a media
         * path in it. Those show up as various VenHw() nodes
         * which are basically opaque to us. Don't count those
         * as something specifc.
         */
        if (last_dp == first_dp) {
                printf("Ignoring Boot%04x: Only one DP found\n", boot_current);
                return NOT_SPECIFIC;
        }
        if (efi_devpath_to_media_path(last_dp) == NULL) {
                printf("Ignoring Boot%04x: No Media Path\n", boot_current);
                return NOT_SPECIFIC;
        }

        /*
         * OK. At this point we either have a good path or a bad one.
         * Let's check.
         */
        pp = efiblk_get_pdinfo_by_device_path(last_dp);
        if (pp == NULL) {
                printf("Ignoring Boot%04x: Device Path not found\n", boot_current);
                return BAD_CHOICE;
        }
        set_currdev_pdinfo(pp);
        if (!sanity_check_currdev()) {
                printf("Ignoring Boot%04x: sanity check failed\n", boot_current);
                return BAD_CHOICE;
        }

        /*
         * OK. We've found a device that matches, next we need to check the last
         * component of the path. If it's a file, then we set the default kernel
         * to that. Otherwise, just use this as the default root.
         *
         * Reminder: we're running very early, before we've parsed the defaults
         * file, so we may need to have a hack override.
         */
        dp = efi_devpath_last_node(last_dp);
        if (DevicePathType(dp) !=  MEDIA_DEVICE_PATH ||
            DevicePathSubType(dp) != MEDIA_FILEPATH_DP) {
                printf("Using Boot%04x for root partition\n", boot_current);
                return (BOOT_INFO_OK);          /* use currdir, default kernel */
        }
        fp = (FILEPATH_DEVICE_PATH *)dp;
        ucs2_to_utf8(fp->PathName, &kernel);
        if (kernel == NULL) {
                printf("Not using Boot%04x: can't decode kernel\n", boot_current);
                return (BAD_CHOICE);
        }
        if (*kernel == '\\' || isupper(*kernel))
                fix_dosisms(kernel);
        if (stat(kernel, &st) != 0) {
                free(kernel);
                printf("Not using Boot%04x: can't find %s\n", boot_current,
                    kernel);
                return (BAD_CHOICE);
        }
        setenv("kernel", kernel, 1);
        free(kernel);
        text = efi_devpath_name(last_dp);
        if (text) {
                printf("Using Boot%04x %S + %s\n", boot_current, text,
                    kernel);
                efi_free_devpath_name(text);
        }

        return (BOOT_INFO_OK);
}

/*
 * Look at the passed-in boot_info, if any. If we find it then we need
 * to see if we can find ourselves in the boot chain. If we can, and
 * there's another specified thing to boot next, assume that the file
 * is loaded from / and use that for the root filesystem. If can't
 * find the specified thing, we must fail the boot. If we're last on
 * the list, then we fallback to looking for the first available /
 * candidate (ZFS, if there's a bootable zpool, otherwise a UFS
 * partition that has either /boot/defaults/loader.conf on it or
 * /boot/kernel/kernel (the default kernel) that we can use.
 *
 * We always fail if we can't find the right thing. However, as
 * a concession to buggy UEFI implementations, like u-boot, if
 * we have determined that the host is violating the UEFI boot
 * manager protocol, we'll signal the rest of the program that
 * a drop to the OK boot loader prompt is possible.
 */
static int
find_currdev(bool do_bootmgr, bool is_last,
    char *boot_info, size_t boot_info_sz)
{
        pdinfo_t *dp, *pp;
        EFI_DEVICE_PATH *devpath, *copy;
        EFI_HANDLE h;
        CHAR16 *text;
        struct devsw *dev;
        int unit;
        uint64_t extra;
        int rv;
        char *rootdev;

        /*
         * First choice: if rootdev is already set, use that, even if
         * it's wrong.
         */
        rootdev = getenv("rootdev");
        if (rootdev != NULL) {
                printf("    Setting currdev to configured rootdev %s\n",
                    rootdev);
                set_currdev(rootdev);
                return (0);
        }

        /*
         * Second choice: If uefi_rootdev is set, translate that UEFI device
         * path to the loader's internal name and use that.
         */
        do {
                rootdev = getenv("uefi_rootdev");
                if (rootdev == NULL)
                        break;
                devpath = efi_name_to_devpath(rootdev);
                if (devpath == NULL)
                        break;
                dp = efiblk_get_pdinfo_by_device_path(devpath);
                efi_devpath_free(devpath);
                if (dp == NULL)
                        break;
                printf("    Setting currdev to UEFI path %s\n",
                    rootdev);
                set_currdev_pdinfo(dp);
                return (0);
        } while (0);

        /*
         * Third choice: If we can find out image boot_info, and there's
         * a follow-on boot image in that boot_info, use that. In this
         * case root will be the partition specified in that image and
         * we'll load the kernel specified by the file path. Should there
         * not be a filepath, we use the default. This filepath overrides
         * loader.conf.
         */
        if (do_bootmgr) {
                rv = match_boot_info(boot_info, boot_info_sz);
                switch (rv) {
                case BOOT_INFO_OK:      /* We found it */
                        return (0);
                case BAD_CHOICE:        /* specified file not found -> error */
                        /* XXX do we want to have an escape hatch for last in boot order? */
                        return (ENOENT);
                } /* Nothing specified, try normal match */
        }

#ifdef EFI_ZFS_BOOT
        /*
         * Did efi_zfs_probe() detect the boot pool? If so, use the zpool
         * it found, if it's sane. ZFS is the only thing that looks for
         * disks and pools to boot. This may change in the future, however,
         * if we allow specifying which pool to boot from via UEFI variables
         * rather than the bootenv stuff that FreeBSD uses today.
         */
        if (pool_guid != 0) {
                printf("Trying ZFS pool\n");
                if (probe_zfs_currdev(pool_guid))
                        return (0);
        }
#endif /* EFI_ZFS_BOOT */

        /*
         * Try to find the block device by its handle based on the
         * image we're booting. If we can't find a sane partition,
         * search all the other partitions of the disk. We do not
         * search other disks because it's a violation of the UEFI
         * boot protocol to do so. We fail and let UEFI go on to
         * the next candidate.
         */
        dp = efiblk_get_pdinfo_by_handle(boot_img->DeviceHandle);
        if (dp != NULL) {
                text = efi_devpath_name(dp->pd_devpath);
                if (text != NULL) {
                        printf("Trying ESP: %S\n", text);
                        efi_free_devpath_name(text);
                }
                set_currdev_pdinfo(dp);
                if (sanity_check_currdev())
                        return (0);
                if (dp->pd_parent != NULL) {
                        pdinfo_t *espdp = dp;
                        dp = dp->pd_parent;
                        STAILQ_FOREACH(pp, &dp->pd_part, pd_link) {
                                /* Already tried the ESP */
                                if (espdp == pp)
                                        continue;
                                /*
                                 * Roll up the ZFS special case
                                 * for those partitions that have
                                 * zpools on them.
                                 */
                                text = efi_devpath_name(pp->pd_devpath);
                                if (text != NULL) {
                                        printf("Trying: %S\n", text);
                                        efi_free_devpath_name(text);
                                }
                                if (try_as_currdev(dp, pp))
                                        return (0);
                        }
                }
        }

        /*
         * Try the device handle from our loaded image first.  If that
         * fails, use the device path from the loaded image and see if
         * any of the nodes in that path match one of the enumerated
         * handles. Currently, this handle list is only for netboot.
         */
        if (efi_handle_lookup(boot_img->DeviceHandle, &dev, &unit, &extra) == 0) {
                set_currdev_devsw(dev, unit);
                if (sanity_check_currdev())
                        return (0);
        }

        copy = NULL;
        devpath = efi_lookup_image_devpath(IH);
        while (devpath != NULL) {
                h = efi_devpath_handle(devpath);
                if (h == NULL)
                        break;

                free(copy);
                copy = NULL;

                if (efi_handle_lookup(h, &dev, &unit, &extra) == 0) {
                        set_currdev_devsw(dev, unit);
                        if (sanity_check_currdev())
                                return (0);
                }

                devpath = efi_lookup_devpath(h);
                if (devpath != NULL) {
                        copy = efi_devpath_trim(devpath);
                        devpath = copy;
                }
        }
        free(copy);

        return (ENOENT);
}

static bool
interactive_interrupt(const char *msg)
{
        time_t now, then, last;

        last = 0;
        now = then = getsecs();
        printf("%s\n", msg);
        if (fail_timeout == -2)         /* Always break to OK */
                return (true);
        if (fail_timeout == -1)         /* Never break to OK */
                return (false);
        do {
                if (last != now) {
                        printf("press any key to interrupt reboot in %d seconds\r",
                            fail_timeout - (int)(now - then));
                        last = now;
                }

                /* XXX no pause or timeout wait for char */
                if (ischar())
                        return (true);
                now = getsecs();
        } while (now - then < fail_timeout);
        return (false);
}

static int
parse_args(int argc, CHAR16 *argv[])
{
        int i, j, howto;
        bool vargood;
        char var[128];

        /*
         * Parse the args to set the console settings, etc
         * boot1.efi passes these in, if it can read /boot.config or /boot/config
         * or iPXE may be setup to pass these in. Or the optional argument in the
         * boot environment was used to pass these arguments in (in which case
         * neither /boot.config nor /boot/config are consulted).
         *
         * Loop through the args, and for each one that contains an '=' that is
         * not the first character, add it to the environment.  This allows
         * loader and kernel env vars to be passed on the command line.  Convert
         * args from UCS-2 to ASCII (16 to 8 bit) as they are copied (though this
         * method is flawed for non-ASCII characters).
         */
        howto = 0;
        for (i = 1; i < argc; i++) {
                cpy16to8(argv[i], var, sizeof(var));
                howto |= boot_parse_arg(var);
        }

        return (howto);
}

static void
setenv_int(const char *key, int val)
{
        char buf[20];

        snprintf(buf, sizeof(buf), "%d", val);
        setenv(key, buf, 1);
}

/*
 * Parse ConOut (the list of consoles active) and see if we can find a
 * serial port and/or a video port. It would be nice to also walk the
 * ACPI name space to map the UID for the serial port to a port. The
 * latter is especially hard.
 */
int
parse_uefi_con_out(void)
{
        int how, rv;
        int vid_seen = 0, com_seen = 0, seen = 0;
        size_t sz;
        char buf[4096], *ep;
        EFI_DEVICE_PATH *node;
        ACPI_HID_DEVICE_PATH  *acpi;
        UART_DEVICE_PATH  *uart;
        bool pci_pending;

        how = 0;
        sz = sizeof(buf);
        rv = efi_global_getenv("ConOut", buf, &sz);
        if (rv != EFI_SUCCESS) {
                /* If we don't have any ConOut default to serial */
                how = RB_SERIAL;
                goto out;
        }
        ep = buf + sz;
        node = (EFI_DEVICE_PATH *)buf;
        while ((char *)node < ep) {
                pci_pending = false;
                if (DevicePathType(node) == ACPI_DEVICE_PATH &&
                    (DevicePathSubType(node) == ACPI_DP ||
                    DevicePathSubType(node) == ACPI_EXTENDED_DP)) {
                        /* Check for Serial node */
                        acpi = (void *)node;
                        if (EISA_ID_TO_NUM(acpi->HID) == 0x501) {
                                setenv_int("efi_8250_uid", acpi->UID);
                                com_seen = ++seen;
                        }
                } else if (DevicePathType(node) == MESSAGING_DEVICE_PATH &&
                    DevicePathSubType(node) == MSG_UART_DP) {
                        com_seen = ++seen;
                        uart = (void *)node;
                        setenv_int("efi_com_speed", uart->BaudRate);
                } else if (DevicePathType(node) == ACPI_DEVICE_PATH &&
                    DevicePathSubType(node) == ACPI_ADR_DP) {
                        /* Check for AcpiAdr() Node for video */
                        vid_seen = ++seen;
                } else if (DevicePathType(node) == HARDWARE_DEVICE_PATH &&
                    DevicePathSubType(node) == HW_PCI_DP) {
                        /*
                         * Note, vmware fusion has a funky console device
                         *      PciRoot(0x0)/Pci(0xf,0x0)
                         * which we can only detect at the end since we also
                         * have to cope with:
                         *      PciRoot(0x0)/Pci(0x1f,0x0)/Serial(0x1)
                         * so only match it if it's last.
                         */
                        pci_pending = true;
                }
                node = NextDevicePathNode(node);
        }
        if (pci_pending && vid_seen == 0)
                vid_seen = ++seen;

        /*
         * Truth table for RB_MULTIPLE | RB_SERIAL
         * Value                Result
         * 0                    Use only video console
         * RB_SERIAL            Use only serial console
         * RB_MULTIPLE          Use both video and serial console
         *                      (but video is primary so gets rc messages)
         * both                 Use both video and serial console
         *                      (but serial is primary so gets rc messages)
         *
         * Try to honor this as best we can. If only one of serial / video
         * found, then use that. Otherwise, use the first one we found.
         * This also implies if we found nothing, default to video.
         */
        how = 0;
        if (vid_seen && com_seen) {
                how |= RB_MULTIPLE;
                if (com_seen < vid_seen)
                        how |= RB_SERIAL;
        } else if (com_seen)
                how |= RB_SERIAL;
out:
        return (how);
}

void
parse_loader_efi_config(EFI_HANDLE h, const char *env_fn)
{
        pdinfo_t *dp;
        struct stat st;
        int fd = -1;
        char *env = NULL;

        dp = efiblk_get_pdinfo_by_handle(h);
        if (dp == NULL)
                return;
        set_currdev_pdinfo(dp);
        if (stat(env_fn, &st) != 0)
                return;
        fd = open(env_fn, O_RDONLY);
        if (fd == -1)
                return;
        env = malloc(st.st_size + 1);
        if (env == NULL)
                goto out;
        if (read(fd, env, st.st_size) != st.st_size)
                goto out;
        env[st.st_size] = '\0';
        boot_parse_cmdline(env);
out:
        free(env);
        close(fd);
}

static void
read_loader_env(const char *name, char *def_fn, bool once)
{
        UINTN len;
        char *fn, *freeme = NULL;

        len = 0;
        fn = def_fn;
        if (efi_freebsd_getenv(name, NULL, &len) == EFI_BUFFER_TOO_SMALL) {
                freeme = fn = malloc(len + 1);
                if (fn != NULL) {
                        if (efi_freebsd_getenv(name, fn, &len) != EFI_SUCCESS) {
                                free(fn);
                                fn = NULL;
                                printf(
                            "Can't fetch FreeBSD::%s we know is there\n", name);
                        } else {
                                /*
                                 * if tagged as 'once' delete the env variable so we
                                 * only use it once.
                                 */
                                if (once)
                                        efi_freebsd_delenv(name);
                                /*
                                 * We malloced 1 more than len above, then redid the call.
                                 * so now we have room at the end of the string to NUL terminate
                                 * it here, even if the typical idium would have '- 1' here to
                                 * not overflow. len should be the same on return both times.
                                 */
                                fn[len] = '\0';
                        }
                } else {
                        printf(
                    "Can't allocate %d bytes to fetch FreeBSD::%s env var\n",
                            len, name);
                }
        }
        if (fn) {
                printf("    Reading loader env vars from %s\n", fn);
                parse_loader_efi_config(boot_img->DeviceHandle, fn);
        }
}

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

EFI_STATUS
main(int argc, CHAR16 *argv[])
{
        EFI_GUID *guid;
        int howto, i, uhowto;
        UINTN k;
        bool has_kbd, is_last;
        char *s;
        EFI_DEVICE_PATH *imgpath;
        CHAR16 *text;
        EFI_STATUS rv;
        size_t sz, bosz = 0, bisz = 0;
        UINT16 boot_order[100];
        char boot_info[4096];
        char buf[32];
        bool uefi_boot_mgr;

        archsw.arch_autoload = efi_autoload;
        archsw.arch_getdev = efi_getdev;
        archsw.arch_copyin = efi_copyin;
        archsw.arch_copyout = efi_copyout;
#ifdef __amd64__
        archsw.arch_hypervisor = x86_hypervisor;
#endif
        archsw.arch_readin = efi_readin;
        archsw.arch_zfs_probe = efi_zfs_probe;

        /* Get our loaded image protocol interface structure. */
        (void) OpenProtocolByHandle(IH, &imgid, (void **)&boot_img);

        /*
         * Chicken-and-egg problem; we want to have console output early, but
         * some console attributes may depend on reading from eg. the boot
         * device, which we can't do yet.  We can use printf() etc. once this is
         * done. So, we set it to the efi console, then call console init. This
         * gets us printf early, but also primes the pump for all future console
         * changes to take effect, regardless of where they come from.
         */
        setenv("console", "efi", 1);
        uhowto = parse_uefi_con_out();
#if defined(__aarch64__) || defined(__arm__) || defined(__riscv)
        if ((uhowto & RB_SERIAL) != 0)
                setenv("console", "comconsole", 1);
#endif
        cons_probe();

        /* Init the time source */
        efi_time_init();

        /*
         * Initialise the block cache. Set the upper limit.
         */
        bcache_init(32768, 512);

        /*
         * Scan the BLOCK IO MEDIA handles then
         * march through the device switch probing for things.
         */
        i = efipart_inithandles();
        if (i != 0 && i != ENOENT) {
                printf("efipart_inithandles failed with ERRNO %d, expect "
                    "failures\n", i);
        }

        for (i = 0; devsw[i] != NULL; i++)
                if (devsw[i]->dv_init != NULL)
                        (devsw[i]->dv_init)();

        /*
         * Detect console settings two different ways: one via the command
         * args (eg -h) or via the UEFI ConOut variable.
         */
        has_kbd = has_keyboard();
        howto = parse_args(argc, argv);
        if (!has_kbd && (howto & RB_PROBE))
                howto |= RB_SERIAL | RB_MULTIPLE;
        howto &= ~RB_PROBE;

        /*
         * Read additional environment variables from the boot device's
         * "LoaderEnv" file. Any boot loader environment variable may be set
         * there, which are subtly different than loader.conf variables. Only
         * the 'simple' ones may be set so things like foo_load="YES" won't work
         * for two reasons.  First, the parser is simplistic and doesn't grok
         * quotes.  Second, because the variables that cause an action to happen
         * are parsed by the lua, 4th or whatever code that's not yet
         * loaded. This is relative to the root directory when loader.efi is
         * loaded off the UFS root drive (when chain booted), or from the ESP
         * when directly loaded by the BIOS.
         *
         * We also read in NextLoaderEnv if it was specified. This allows next boot
         * functionality to be implemented and to override anything in LoaderEnv.
         */
        read_loader_env("LoaderEnv", "/efi/freebsd/loader.env", false);
        read_loader_env("NextLoaderEnv", NULL, true);

        /*
         * We now have two notions of console. howto should be viewed as
         * overrides. If console is already set, don't set it again.
         */
#define VIDEO_ONLY      0
#define SERIAL_ONLY     RB_SERIAL
#define VID_SER_BOTH    RB_MULTIPLE
#define SER_VID_BOTH    (RB_SERIAL | RB_MULTIPLE)
#define CON_MASK        (RB_SERIAL | RB_MULTIPLE)
        if (strcmp(getenv("console"), "efi") == 0) {
                if ((howto & CON_MASK) == 0) {
                        /* No override, uhowto is controlling and efi cons is perfect */
                        howto = howto | (uhowto & CON_MASK);
                } else if ((howto & CON_MASK) == (uhowto & CON_MASK)) {
                        /* override matches what UEFI told us, efi console is perfect */
                } else if ((uhowto & (CON_MASK)) != 0) {
                        /*
                         * We detected a serial console on ConOut. All possible
                         * overrides include serial. We can't really override what efi
                         * gives us, so we use it knowing it's the best choice.
                         */
                        /* Do nothing */
                } else {
                        /*
                         * We detected some kind of serial in the override, but ConOut
                         * has no serial, so we have to sort out which case it really is.
                         */
                        switch (howto & CON_MASK) {
                        case SERIAL_ONLY:
                                setenv("console", "comconsole", 1);
                                break;
                        case VID_SER_BOTH:
                                setenv("console", "efi comconsole", 1);
                                break;
                        case SER_VID_BOTH:
                                setenv("console", "comconsole efi", 1);
                                break;
                                /* case VIDEO_ONLY can't happen -- it's the first if above */
                        }
                }
        }

        /*
         * howto is set now how we want to export the flags to the kernel, so
         * set the env based on it.
         */
        boot_howto_to_env(howto);

        if (efi_copy_init()) {
                printf("failed to allocate staging area\n");
                return (EFI_BUFFER_TOO_SMALL);
        }

        if ((s = getenv("fail_timeout")) != NULL)
                fail_timeout = strtol(s, NULL, 10);

        printf("%s\n", bootprog_info);
        printf("   Command line arguments:");
        for (i = 0; i < argc; i++)
                printf(" %S", argv[i]);
        printf("\n");

        printf("   Image base: 0x%lx\n", (unsigned long)boot_img->ImageBase);
        printf("   EFI version: %d.%02d\n", ST->Hdr.Revision >> 16,
            ST->Hdr.Revision & 0xffff);
        printf("   EFI Firmware: %S (rev %d.%02d)\n", ST->FirmwareVendor,
            ST->FirmwareRevision >> 16, ST->FirmwareRevision & 0xffff);
        printf("   Console: %s (%#x)\n", getenv("console"), howto);

        /* Determine the devpath of our image so we can prefer it. */
        text = efi_devpath_name(boot_img->FilePath);
        if (text != NULL) {
                printf("   Load Path: %S\n", text);
                efi_setenv_freebsd_wcs("LoaderPath", text);
                efi_free_devpath_name(text);
        }

        rv = OpenProtocolByHandle(boot_img->DeviceHandle, &devid,
            (void **)&imgpath);
        if (rv == EFI_SUCCESS) {
                text = efi_devpath_name(imgpath);
                if (text != NULL) {
                        printf("   Load Device: %S\n", text);
                        efi_setenv_freebsd_wcs("LoaderDev", text);
                        efi_free_devpath_name(text);
                }
        }

        if (getenv("uefi_ignore_boot_mgr") != NULL) {
                printf("    Ignoring UEFI boot manager\n");
                uefi_boot_mgr = false;
        } else {
                uefi_boot_mgr = true;
                boot_current = 0;
                sz = sizeof(boot_current);
                rv = efi_global_getenv("BootCurrent", &boot_current, &sz);
                if (rv == EFI_SUCCESS)
                        printf("   BootCurrent: %04x\n", boot_current);
                else {
                        boot_current = 0xffff;
                        uefi_boot_mgr = false;
                }

                sz = sizeof(boot_order);
                rv = efi_global_getenv("BootOrder", &boot_order, &sz);
                if (rv == EFI_SUCCESS) {
                        printf("   BootOrder:");
                        for (i = 0; i < sz / sizeof(boot_order[0]); i++)
                                printf(" %04x%s", boot_order[i],
                                    boot_order[i] == boot_current ? "[*]" : "");
                        printf("\n");
                        is_last = boot_order[(sz / sizeof(boot_order[0])) - 1] == boot_current;
                        bosz = sz;
                } else if (uefi_boot_mgr) {
                        /*
                         * u-boot doesn't set BootOrder, but otherwise participates in the
                         * boot manager protocol. So we fake it here and don't consider it
                         * a failure.
                         */
                        bosz = sizeof(boot_order[0]);
                        boot_order[0] = boot_current;
                        is_last = true;
                }
        }

        /*
         * Next, find the boot info structure the UEFI boot manager is
         * supposed to setup. We need this so we can walk through it to
         * find where we are in the booting process and what to try to
         * boot next.
         */
        if (uefi_boot_mgr) {
                snprintf(buf, sizeof(buf), "Boot%04X", boot_current);
                sz = sizeof(boot_info);
                rv = efi_global_getenv(buf, &boot_info, &sz);
                if (rv == EFI_SUCCESS)
                        bisz = sz;
                else
                        uefi_boot_mgr = false;
        }

        /*
         * Disable the watchdog timer. By default the boot manager sets
         * the timer to 5 minutes before invoking a boot option. If we
         * want to return to the boot manager, we have to disable the
         * watchdog timer and since we're an interactive program, we don't
         * want to wait until the user types "quit". The timer may have
         * fired by then. We don't care if this fails. It does not prevent
         * normal functioning in any way...
         */
        BS->SetWatchdogTimer(0, 0, 0, NULL);

        /*
         * Initialize the trusted/forbidden certificates from UEFI.
         * They will be later used to verify the manifest(s),
         * which should contain hashes of verified files.
         * This needs to be initialized before any configuration files
         * are loaded.
         */
#ifdef EFI_SECUREBOOT
        ve_efi_init();
#endif

        /*
         * Try and find a good currdev based on the image that was booted.
         * It might be desirable here to have a short pause to allow falling
         * through to the boot loader instead of returning instantly to follow
         * the boot protocol and also allow an escape hatch for users wishing
         * to try something different.
         */
        if (find_currdev(uefi_boot_mgr, is_last, boot_info, bisz) != 0)
                if (uefi_boot_mgr &&
                    !interactive_interrupt("Failed to find bootable partition"))
                        return (EFI_NOT_FOUND);

        efi_init_environment();

#if !defined(__arm__)
        for (k = 0; k < ST->NumberOfTableEntries; k++) {
                guid = &ST->ConfigurationTable[k].VendorGuid;
                if (!memcmp(guid, &smbios, sizeof(EFI_GUID))) {
                        char buf[40];

                        snprintf(buf, sizeof(buf), "%p",
                            ST->ConfigurationTable[k].VendorTable);
                        setenv("hint.smbios.0.mem", buf, 1);
                        smbios_detect(ST->ConfigurationTable[k].VendorTable);
                        break;
                }
        }
#endif

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

        return (EFI_SUCCESS);           /* keep compiler happy */
}

COMMAND_SET(poweroff, "poweroff", "power off the system", command_poweroff);

static int
command_poweroff(int argc __unused, char *argv[] __unused)
{
        int i;

        for (i = 0; devsw[i] != NULL; ++i)
                if (devsw[i]->dv_cleanup != NULL)
                        (devsw[i]->dv_cleanup)();

        RS->ResetSystem(EfiResetShutdown, EFI_SUCCESS, 0, NULL);

        /* NOTREACHED */
        return (CMD_ERROR);
}

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

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

        for (i = 0; devsw[i] != NULL; ++i)
                if (devsw[i]->dv_cleanup != NULL)
                        (devsw[i]->dv_cleanup)();

        RS->ResetSystem(EfiResetCold, EFI_SUCCESS, 0, NULL);

        /* NOTREACHED */
        return (CMD_ERROR);
}

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

static int
command_quit(int argc, char *argv[])
{
        exit(0);
        return (CMD_OK);
}

COMMAND_SET(memmap, "memmap", "print memory map", command_memmap);

static int
command_memmap(int argc __unused, char *argv[] __unused)
{
        UINTN sz;
        EFI_MEMORY_DESCRIPTOR *map, *p;
        UINTN key, dsz;
        UINT32 dver;
        EFI_STATUS status;
        int i, ndesc;
        char line[80];

        sz = 0;
        status = BS->GetMemoryMap(&sz, 0, &key, &dsz, &dver);
        if (status != EFI_BUFFER_TOO_SMALL) {
                printf("Can't determine memory map size\n");
                return (CMD_ERROR);
        }
        map = malloc(sz);
        status = BS->GetMemoryMap(&sz, map, &key, &dsz, &dver);
        if (EFI_ERROR(status)) {
                printf("Can't read memory map\n");
                return (CMD_ERROR);
        }

        ndesc = sz / dsz;
        snprintf(line, sizeof(line), "%23s %12s %12s %8s %4s\n",
            "Type", "Physical", "Virtual", "#Pages", "Attr");
        pager_open();
        if (pager_output(line)) {
                pager_close();
                return (CMD_OK);
        }

        for (i = 0, p = map; i < ndesc;
             i++, p = NextMemoryDescriptor(p, dsz)) {
                snprintf(line, sizeof(line), "%23s %012jx %012jx %08jx ",
                    efi_memory_type(p->Type), (uintmax_t)p->PhysicalStart,
                    (uintmax_t)p->VirtualStart, (uintmax_t)p->NumberOfPages);
                if (pager_output(line))
                        break;

                if (p->Attribute & EFI_MEMORY_UC)
                        printf("UC ");
                if (p->Attribute & EFI_MEMORY_WC)
                        printf("WC ");
                if (p->Attribute & EFI_MEMORY_WT)
                        printf("WT ");
                if (p->Attribute & EFI_MEMORY_WB)
                        printf("WB ");
                if (p->Attribute & EFI_MEMORY_UCE)
                        printf("UCE ");
                if (p->Attribute & EFI_MEMORY_WP)
                        printf("WP ");
                if (p->Attribute & EFI_MEMORY_RP)
                        printf("RP ");
                if (p->Attribute & EFI_MEMORY_XP)
                        printf("XP ");
                if (p->Attribute & EFI_MEMORY_NV)
                        printf("NV ");
                if (p->Attribute & EFI_MEMORY_MORE_RELIABLE)
                        printf("MR ");
                if (p->Attribute & EFI_MEMORY_RO)
                        printf("RO ");
                if (pager_output("\n"))
                        break;
        }

        pager_close();
        return (CMD_OK);
}

COMMAND_SET(configuration, "configuration", "print configuration tables",
    command_configuration);

static int
command_configuration(int argc, char *argv[])
{
        UINTN i;
        char *name;

        printf("NumberOfTableEntries=%lu\n",
                (unsigned long)ST->NumberOfTableEntries);

        for (i = 0; i < ST->NumberOfTableEntries; i++) {
                EFI_GUID *guid;

                printf("  ");
                guid = &ST->ConfigurationTable[i].VendorGuid;

                if (efi_guid_to_name(guid, &name) == true) {
                        printf(name);
                        free(name);
                } else {
                        printf("Error while translating UUID to name");
                }
                printf(" at %p\n", ST->ConfigurationTable[i].VendorTable);
        }

        return (CMD_OK);
}


COMMAND_SET(mode, "mode", "change or display EFI text modes", command_mode);

static int
command_mode(int argc, char *argv[])
{
        UINTN cols, rows;
        unsigned int mode;
        int i;
        char *cp;
        EFI_STATUS status;
        SIMPLE_TEXT_OUTPUT_INTERFACE *conout;

        conout = ST->ConOut;

        if (argc > 1) {
                mode = strtol(argv[1], &cp, 0);
                if (cp[0] != '\0') {
                        printf("Invalid mode\n");
                        return (CMD_ERROR);
                }
                status = conout->QueryMode(conout, mode, &cols, &rows);
                if (EFI_ERROR(status)) {
                        printf("invalid mode %d\n", mode);
                        return (CMD_ERROR);
                }
                status = conout->SetMode(conout, mode);
                if (EFI_ERROR(status)) {
                        printf("couldn't set mode %d\n", mode);
                        return (CMD_ERROR);
                }
                (void) efi_cons_update_mode();
                return (CMD_OK);
        }

        printf("Current mode: %d\n", conout->Mode->Mode);
        for (i = 0; i <= conout->Mode->MaxMode; i++) {
                status = conout->QueryMode(conout, i, &cols, &rows);
                if (EFI_ERROR(status))
                        continue;
                printf("Mode %d: %u columns, %u rows\n", i, (unsigned)cols,
                    (unsigned)rows);
        }

        if (i != 0)
                printf("Select a mode with the command \"mode <number>\"\n");

        return (CMD_OK);
}

COMMAND_SET(lsefi, "lsefi", "list EFI handles", command_lsefi);

static int
command_lsefi(int argc __unused, char *argv[] __unused)
{
        char *name;
        EFI_HANDLE *buffer = NULL;
        EFI_HANDLE handle;
        UINTN bufsz = 0, i, j;
        EFI_STATUS status;
        int ret = 0;

        status = BS->LocateHandle(AllHandles, NULL, NULL, &bufsz, buffer);
        if (status != EFI_BUFFER_TOO_SMALL) {
                snprintf(command_errbuf, sizeof (command_errbuf),
                    "unexpected error: %lld", (long long)status);
                return (CMD_ERROR);
        }
        if ((buffer = malloc(bufsz)) == NULL) {
                sprintf(command_errbuf, "out of memory");
                return (CMD_ERROR);
        }

        status = BS->LocateHandle(AllHandles, NULL, NULL, &bufsz, buffer);
        if (EFI_ERROR(status)) {
                free(buffer);
                snprintf(command_errbuf, sizeof (command_errbuf),
                    "LocateHandle() error: %lld", (long long)status);
                return (CMD_ERROR);
        }

        pager_open();
        for (i = 0; i < (bufsz / sizeof (EFI_HANDLE)); i++) {
                UINTN nproto = 0;
                EFI_GUID **protocols = NULL;

                handle = buffer[i];
                printf("Handle %p", handle);
                if (pager_output("\n"))
                        break;
                /* device path */

                status = BS->ProtocolsPerHandle(handle, &protocols, &nproto);
                if (EFI_ERROR(status)) {
                        snprintf(command_errbuf, sizeof (command_errbuf),
                            "ProtocolsPerHandle() error: %lld",
                            (long long)status);
                        continue;
                }

                for (j = 0; j < nproto; j++) {
                        if (efi_guid_to_name(protocols[j], &name) == true) {
                                printf("  %s", name);
                                free(name);
                        } else {
                                printf("Error while translating UUID to name");
                        }
                        if ((ret = pager_output("\n")) != 0)
                                break;
                }
                BS->FreePool(protocols);
                if (ret != 0)
                        break;
        }
        pager_close();
        free(buffer);
        return (CMD_OK);
}

#ifdef LOADER_FDT_SUPPORT
extern int command_fdt_internal(int argc, char *argv[]);

/*
 * Since proper fdt command handling function is defined in fdt_loader_cmd.c,
 * and declaring it as extern is in contradiction with COMMAND_SET() macro
 * (which uses static pointer), we're defining wrapper function, which
 * calls the proper fdt handling routine.
 */
static int
command_fdt(int argc, char *argv[])
{

        return (command_fdt_internal(argc, argv));
}

COMMAND_SET(fdt, "fdt", "flattened device tree handling", command_fdt);
#endif

/*
 * Chain load another efi loader.
 */
static int
command_chain(int argc, char *argv[])
{
        EFI_GUID LoadedImageGUID = LOADED_IMAGE_PROTOCOL;
        EFI_HANDLE loaderhandle;
        EFI_LOADED_IMAGE *loaded_image;
        EFI_STATUS status;
        struct stat st;
        struct devdesc *dev;
        char *name, *path;
        void *buf;
        int fd;

        if (argc < 2) {
                command_errmsg = "wrong number of arguments";
                return (CMD_ERROR);
        }

        name = argv[1];

        if ((fd = open(name, O_RDONLY)) < 0) {
                command_errmsg = "no such file";
                return (CMD_ERROR);
        }

#ifdef LOADER_VERIEXEC
        if (verify_file(fd, name, 0, VE_MUST, __func__) < 0) {
                sprintf(command_errbuf, "can't verify: %s", name);
                close(fd);
                return (CMD_ERROR);
        }
#endif

        if (fstat(fd, &st) < -1) {
                command_errmsg = "stat failed";
                close(fd);
                return (CMD_ERROR);
        }

        status = BS->AllocatePool(EfiLoaderCode, (UINTN)st.st_size, &buf);
        if (status != EFI_SUCCESS) {
                command_errmsg = "failed to allocate buffer";
                close(fd);
                return (CMD_ERROR);
        }
        if (read(fd, buf, st.st_size) != st.st_size) {
                command_errmsg = "error while reading the file";
                (void)BS->FreePool(buf);
                close(fd);
                return (CMD_ERROR);
        }
        close(fd);
        status = BS->LoadImage(FALSE, IH, NULL, buf, st.st_size, &loaderhandle);
        (void)BS->FreePool(buf);
        if (status != EFI_SUCCESS) {
                command_errmsg = "LoadImage failed";
                return (CMD_ERROR);
        }
        status = OpenProtocolByHandle(loaderhandle, &LoadedImageGUID,
            (void **)&loaded_image);

        if (argc > 2) {
                int i, len = 0;
                CHAR16 *argp;

                for (i = 2; i < argc; i++)
                        len += strlen(argv[i]) + 1;

                len *= sizeof (*argp);
                loaded_image->LoadOptions = argp = malloc (len);
                loaded_image->LoadOptionsSize = len;
                for (i = 2; i < argc; i++) {
                        char *ptr = argv[i];
                        while (*ptr)
                                *(argp++) = *(ptr++);
                        *(argp++) = ' ';
                }
                *(--argv) = 0;
        }

        if (efi_getdev((void **)&dev, name, (const char **)&path) == 0) {
#ifdef EFI_ZFS_BOOT
                struct zfs_devdesc *z_dev;
#endif
                struct disk_devdesc *d_dev;
                pdinfo_t *hd, *pd;

                switch (dev->d_dev->dv_type) {
#ifdef EFI_ZFS_BOOT
                case DEVT_ZFS:
                        z_dev = (struct zfs_devdesc *)dev;
                        loaded_image->DeviceHandle =
                            efizfs_get_handle_by_guid(z_dev->pool_guid);
                        break;
#endif
                case DEVT_NET:
                        loaded_image->DeviceHandle =
                            efi_find_handle(dev->d_dev, dev->d_unit);
                        break;
                default:
                        hd = efiblk_get_pdinfo(dev);
                        if (STAILQ_EMPTY(&hd->pd_part)) {
                                loaded_image->DeviceHandle = hd->pd_handle;
                                break;
                        }
                        d_dev = (struct disk_devdesc *)dev;
                        STAILQ_FOREACH(pd, &hd->pd_part, pd_link) {
                                /*
                                 * d_partition should be 255
                                 */
                                if (pd->pd_unit == (uint32_t)d_dev->d_slice) {
                                        loaded_image->DeviceHandle =
                                            pd->pd_handle;
                                        break;
                                }
                        }
                        break;
                }
        }

        dev_cleanup();
        status = BS->StartImage(loaderhandle, NULL, NULL);
        if (status != EFI_SUCCESS) {
                command_errmsg = "StartImage failed";
                free(loaded_image->LoadOptions);
                loaded_image->LoadOptions = NULL;
                status = BS->UnloadImage(loaded_image);
                return (CMD_ERROR);
        }

        return (CMD_ERROR);     /* not reached */
}

COMMAND_SET(chain, "chain", "chain load file", command_chain);