boot/bootadm/bootadm_upgrade.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2016 Toomas Soome <tsoome@me.com>
 */

#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <limits.h>
#include <fcntl.h>
#include <strings.h>

#include <sys/mman.h>
#include <sys/elf.h>
#include <sys/multiboot.h>

#include "bootadm.h"

direct_or_multi_t bam_direct = BAM_DIRECT_NOT_SET;
hv_t bam_is_hv = BAM_HV_UNKNOWN;
findroot_t bam_is_findroot = BAM_FINDROOT_UNKNOWN;

static void
get_findroot_cap(const char *osroot)
{
    FILE        *fp;
    char        path[PATH_MAX];
    char        buf[BAM_MAXLINE];
    struct stat sb;
    int     dboot;
    int     error;
    int     ret;
    const char  *fcn = "get_findroot_cap()";

    (void) snprintf(path, sizeof (path), "%s/%s",
        osroot, "boot/grub/capability");

    if (stat(path, &sb) == -1) {
        bam_is_findroot = BAM_FINDROOT_ABSENT;
        BAM_DPRINTF(("%s: findroot capability absent\n", fcn));
        return;
    }

    fp = fopen(path, "r");
    error = errno;
    INJECT_ERROR1("GET_CAP_FINDROOT_FOPEN", fp = NULL);
    if (fp == NULL) {
        bam_error(_("failed to open file: %s: %s\n"), path,
            strerror(error));
        return;
    }

    dboot = 0;
    while (s_fgets(buf, sizeof (buf), fp) != NULL) {
        if (strcmp(buf, "findroot") == 0) {
            BAM_DPRINTF(("%s: findroot capability present\n", fcn));
            bam_is_findroot = BAM_FINDROOT_PRESENT;
        }
        if (strcmp(buf, "dboot") == 0) {
            BAM_DPRINTF(("%s: dboot capability present\n", fcn));
            dboot = 1;
        }
    }

    assert(dboot);

    if (bam_is_findroot == BAM_FINDROOT_UNKNOWN) {
        bam_is_findroot = BAM_FINDROOT_ABSENT;
        BAM_DPRINTF(("%s: findroot capability absent\n", fcn));
    }

    ret = fclose(fp);
    error = errno;
    INJECT_ERROR1("GET_CAP_FINDROOT_FCLOSE", ret = 1);
    if (ret != 0) {
        bam_error(_("failed to close file: %s: %s\n"),
            path, strerror(error));
    }
}

error_t
get_boot_cap(const char *osroot)
{
    char        fname[PATH_MAX];
    char        *image;
    uchar_t     *ident;
    int     fd;
    int     m;
    multiboot_header_t *mbh;
    struct stat sb;
    int     error;
    const char  *fcn = "get_boot_cap()";

    if (is_sparc()) {
        /* there is no non dboot sparc new-boot */
        bam_direct = BAM_DIRECT_DBOOT;
        BAM_DPRINTF(("%s: is sparc - always DBOOT\n", fcn));
        return (BAM_SUCCESS);
    }

    (void) snprintf(fname, PATH_MAX, "%s/%s", osroot,
        "platform/i86pc/kernel/unix");
    fd = open(fname, O_RDONLY);
    error = errno;
    INJECT_ERROR1("GET_CAP_UNIX_OPEN", fd = -1);
    if (fd < 0) {
        bam_error(_("failed to open file: %s: %s\n"), fname,
            strerror(error));
        return (BAM_ERROR);
    }

    /*
     * Verify that this is a sane unix at least 8192 bytes in length
     */
    if (fstat(fd, &sb) == -1 || sb.st_size < 8192) {
        (void) close(fd);
        bam_error(_("invalid or corrupted binary: %s\n"), fname);
        return (BAM_ERROR);
    }

    /*
     * mmap the first 8K
     */
    image = mmap(NULL, 8192, PROT_READ, MAP_SHARED, fd, 0);
    error = errno;
    INJECT_ERROR1("GET_CAP_MMAP", image = MAP_FAILED);
    if (image == MAP_FAILED) {
        bam_error(_("failed to mmap file: %s: %s\n"), fname,
            strerror(error));
        return (BAM_ERROR);
    }

    ident = (uchar_t *)image;
    if (ident[EI_MAG0] != ELFMAG0 || ident[EI_MAG1] != ELFMAG1 ||
        ident[EI_MAG2] != ELFMAG2 || ident[EI_MAG3] != ELFMAG3) {
        bam_error(_("%s is not an ELF file.\n"), fname);
        return (BAM_ERROR);
    }
    if (ident[EI_CLASS] != ELFCLASS32) {
        bam_error(_("%s is wrong ELF class 0x%x\n"), fname,
            ident[EI_CLASS]);
        return (BAM_ERROR);
    }

    /*
     * The GRUB multiboot header must be 32-bit aligned and completely
     * contained in the 1st 8K of the file.  If the unix binary has
     * a multiboot header, then it is a 'dboot' kernel.  Otherwise,
     * this kernel must be booted via multiboot -- we call this a
     * 'multiboot' kernel.
     */
    bam_direct = BAM_DIRECT_MULTIBOOT;
    for (m = 0; m < 8192 - sizeof (multiboot_header_t); m += 4) {
        mbh = (void *)(image + m);
        if (mbh->magic == MB_HEADER_MAGIC) {
            BAM_DPRINTF(("%s: is DBOOT unix\n", fcn));
            bam_direct = BAM_DIRECT_DBOOT;
            break;
        }
    }
    (void) munmap(image, 8192);
    (void) close(fd);

    INJECT_ERROR1("GET_CAP_MULTIBOOT", bam_direct = BAM_DIRECT_MULTIBOOT);
    if (bam_direct == BAM_DIRECT_DBOOT) {
        if (bam_is_hv == BAM_HV_PRESENT) {
            BAM_DPRINTF(("%s: is xVM system\n", fcn));
        } else {
            BAM_DPRINTF(("%s: is *NOT* xVM system\n", fcn));
        }
    } else {
        BAM_DPRINTF(("%s: is MULTIBOOT unix\n", fcn));
    }

    /* Not a fatal error if this fails */
    get_findroot_cap(osroot);

    BAM_DPRINTF(("%s: returning SUCCESS\n", fcn));
    return (BAM_SUCCESS);
}

#define INST_RELEASE    "var/sadm/system/admin/INST_RELEASE"

/*
 * Return true if root has been bfu'ed.  bfu will blow away
 * var/sadm/system/admin/INST_RELEASE, so if it's still there, we can
 * assume the system has not been bfu'ed.
 */
static int
is_bfu_system(const char *root)
{
    static int      is_bfu = -1;
    char            path[PATH_MAX];
    struct stat     sb;
    const char      *fcn = "is_bfu_system()";

    if (is_bfu != -1) {
        BAM_DPRINTF(("%s: already done bfu test. bfu is %s present\n",
            fcn, is_bfu ? "" : "NOT"));
        return (is_bfu);
    }

    (void) snprintf(path, sizeof (path), "%s/%s", root, INST_RELEASE);
    if (stat(path, &sb) != 0) {
        is_bfu = 1;
        BAM_DPRINTF(("%s: returning SUCCESS\n", fcn));
    } else {
        is_bfu = 0;
        BAM_DPRINTF(("%s: returning FAILURE\n", fcn));
    }
    return (is_bfu);
}

#define MENU_URL(root)  (is_bfu_system(root) ?      \
    "http://illumos.org/msg/SUNOS-8000-CF" :    \
    "http://illumos.org/msg/SUNOS-8000-AK")

/*
 * Simply allocate a new line and copy in cmd + sep + arg
 */
void
update_line(line_t *linep)
{
    size_t      size;
    const char  *fcn = "update_line()";

    BAM_DPRINTF(("%s: line before update: %s\n", fcn, linep->line));
    free(linep->line);
    size = strlen(linep->cmd) + strlen(linep->sep) + strlen(linep->arg) + 1;
    linep->line = s_calloc(1, size);
    (void) snprintf(linep->line, size, "%s%s%s", linep->cmd, linep->sep,
        linep->arg);
    BAM_DPRINTF(("%s: line after update: %s\n", fcn, linep->line));
}

static char *
skip_wspace(char *ptr)
{
    const char      *fcn = "skip_wspace()";

    INJECT_ERROR1("SKIP_WSPACE", ptr = NULL);
    if (ptr == NULL) {
        BAM_DPRINTF(("%s: NULL ptr\n", fcn));
        return (NULL);
    }

    BAM_DPRINTF(("%s: ptr on entry: %s\n", fcn, ptr));
    for (; *ptr != '\0'; ptr++) {
        if ((*ptr != ' ') && (*ptr != '\t') &&
            (*ptr != '\n'))
            break;
    }

    ptr = (*ptr == '\0' ? NULL : ptr);

    BAM_DPRINTF(("%s: ptr on exit: %s\n", fcn, ptr ? ptr : "NULL"));

    return (ptr);
}

static char *
rskip_bspace(char *bound, char *ptr)
{
    const char      *fcn = "rskip_bspace()";
    assert(bound);
    assert(ptr);
    assert(bound <= ptr);
    assert(*bound != ' ' && *bound != '\t' && *bound != '\n');

    BAM_DPRINTF(("%s: ptr on entry: %s\n", fcn, ptr));
    for (; ptr > bound; ptr--) {
        if (*ptr == ' ' || *ptr == '\t' || *ptr == '\n')
            break;
    }

    BAM_DPRINTF(("%s: ptr on exit: %s\n", fcn, ptr));
    return (ptr);
}

/*
 * The parse_kernel_line function examines a menu.lst kernel line.  For
 * multiboot, this is:
 *
 * kernel <multiboot path> <flags1> <kernel path> <flags2>
 *
 * <multiboot path> is either /platform/i86pc/multiboot or /boot/multiboot
 *
 * <kernel path> may be missing, or may be any full or relative path to unix.
 *  We check for it by looking for a word ending in "/unix".  If it ends
 *  in "kernel/unix", we upgrade it to a 32-bit entry.  If it ends in
 *  "kernel/amd64/unix", we upgrade it to the default entry.  Otherwise,
 *  it's a custom kernel, and we skip it.
 *
 * <flags*> are anything that doesn't fit either of the above - these will be
 *  copied over.
 *
 * For direct boot, the defaults are
 *
 * kernel$ <kernel path> <flags>
 *
 * <kernel path> is one of:
 *  /platform/i86pc/kernel/$ISADIR/unix
 *  /boot/platform/i86pc/kernel/$ISADIR/unix
 *  /platform/i86pc/kernel/unix
 *  /platform/i86pc/kernel/amd64/unix
 *  /boot/platform/i86pc/kernel/unix
 *  /boot/platform/i86pc/kernel/amd64/unix
 *
 * If <kernel path> is any of the last four, the command may also be "kernel".
 *
 * <flags> is anything that isn't <kernel path>.
 *
 * This function is only called to convert a multiboot entry to a dboot entry
 *
 * For safety, we do one more check: if the kernel path starts with /boot,
 * we verify that the new kernel exists before changing it.  This is mainly
 * done for bfu, as it may cause the failsafe archives to be a different
 * boot architecture from the newly bfu'ed system.
 */
static error_t
cvt_kernel_line(line_t *line, const char *osroot, entry_t *entry)
{
    char        path[PATH_MAX], path_64[PATH_MAX];
    char        linebuf[PATH_MAX];
    char        new_arg[PATH_MAX];
    struct stat sb, sb_64;
    char        *old_ptr;
    char        *unix_ptr;
    char        *flags1_ptr;
    char        *flags2_ptr;
    const char  *fcn = "cvt_kernel_line()";

    BAM_DPRINTF(("%s: entered. args: %s %s\n", fcn, line->line, osroot));

    /*
     * We only convert multiboot to dboot and nothing else.
     */
    if (!(entry->flags & BAM_ENTRY_MULTIBOOT)) {
        BAM_DPRINTF(("%s: not MULTIBOOT, not converting\n", fcn));
        return (BAM_SUCCESS);
    }

    if (entry->flags & BAM_ENTRY_FAILSAFE) {
        /*
         * We're attempting to change failsafe to dboot.
         * In the bfu case, we may not have a dboot failsafe
         * kernel i.e. a "unix" under the "/boot" hierarchy.
         * If so, just emit a message in verbose mode and
         * return success.
         */
        BAM_DPRINTF(("%s: trying to convert failsafe to DBOOT\n", fcn));
        (void) snprintf(path, PATH_MAX, "%s%s", osroot,
            DIRECT_BOOT_FAILSAFE_32);
        (void) snprintf(path_64, PATH_MAX, "%s%s", osroot,
            DIRECT_BOOT_FAILSAFE_64);
        if (stat(path, &sb) != 0 && stat(path_64, &sb_64) != 0) {
            if (bam_verbose) {
                bam_error(_("bootadm -m upgrade run, but the "
                    "failsafe archives have not been\nupdated. "
                    "Not updating line %d\n"), line->lineNum);
            }
            BAM_DPRINTF(("%s: no FAILSAFE unix, not converting\n",
                fcn));
            return (BAM_SUCCESS);
        }
    }

    /*
     * Make sure we have the correct cmd
     */

    free(line->cmd);
    line->cmd = s_strdup(menu_cmds[KERNEL_DOLLAR_CMD]);
    BAM_DPRINTF(("%s: converted kernel cmd to %s\n", fcn, line->cmd));

    assert(sizeof (linebuf) > strlen(line->arg) + 32);
    (void) strlcpy(linebuf, line->arg, sizeof (linebuf));

    old_ptr = strpbrk(linebuf, " \t\n");
    old_ptr = skip_wspace(old_ptr);
    if (old_ptr == NULL) {
        /*
         * only multiboot and nothing else
         * i.e. flags1 = unix = flags2 = NULL
         */
        flags1_ptr = unix_ptr = flags2_ptr = NULL;
        BAM_DPRINTF(("%s: NULL flags1, unix, flags2\n", fcn))
        goto create;
    }

    /*
     *
     * old_ptr is either at "flags1" or "unix"
     */
    if ((unix_ptr = strstr(old_ptr, "/unix")) != NULL) {

        /*
         * There is a  unix.
         */
        BAM_DPRINTF(("%s: unix present\n", fcn));

        /* See if there's a flags2 past unix */
        flags2_ptr = unix_ptr + strlen("/unix");
        flags2_ptr = skip_wspace(flags2_ptr);
        if (flags2_ptr) {
            BAM_DPRINTF(("%s: flags2 present: %s\n", fcn,
                flags2_ptr));
        } else {
            BAM_DPRINTF(("%s: flags2 absent\n", fcn));
        }

        /* see if there is a flags1 before unix */
        unix_ptr = rskip_bspace(old_ptr, unix_ptr);

        if (unix_ptr == old_ptr) {
            flags1_ptr = NULL;
            BAM_DPRINTF(("%s: flags1 absent\n", fcn));
        } else {
            flags1_ptr = old_ptr;
            *unix_ptr = '\0';
            unix_ptr++;
            BAM_DPRINTF(("%s: flags1 present: %s\n", fcn,
                flags1_ptr));
        }

    } else  {
        /* There is no unix, there is only a bunch of flags */
        flags1_ptr = old_ptr;
        unix_ptr = flags2_ptr = NULL;
        BAM_DPRINTF(("%s: flags1 present: %s, unix, flags2 absent\n",
            fcn, flags1_ptr));
    }

    /*
     * With dboot, unix is fixed and is at the beginning. We need to
     * migrate flags1 and flags2
     */
create:
    if (entry->flags & BAM_ENTRY_FAILSAFE) {
        (void) snprintf(new_arg, sizeof (new_arg), "%s",
            DIRECT_BOOT_FAILSAFE_KERNEL);
    } else {
        (void) snprintf(new_arg, sizeof (new_arg), "%s",
            DIRECT_BOOT_KERNEL);
    }
    BAM_DPRINTF(("%s: converted unix: %s\n", fcn, new_arg));

    if (flags1_ptr != NULL) {
        (void) strlcat(new_arg, " ", sizeof (new_arg));
        (void) strlcat(new_arg, flags1_ptr, sizeof (new_arg));
    }

    if (flags2_ptr != NULL) {
        (void) strlcat(new_arg, " ", sizeof (new_arg));
        (void) strlcat(new_arg, flags2_ptr, sizeof (new_arg));
    }

    BAM_DPRINTF(("%s: converted unix with flags : %s\n", fcn, new_arg));

    free(line->arg);
    line->arg = s_strdup(new_arg);
    update_line(line);
    BAM_DPRINTF(("%s: converted line is: %s\n", fcn, line->line));
    return (BAM_SUCCESS);
}

/*
 * Similar to above, except this time we're looking at a module line,
 * which is quite a bit simpler.
 *
 * Under multiboot, the archive line is:
 *
 * module /platform/i86pc/boot_archive
 *
 * Under directboot, the archive line is:
 *
 * module$ /platform/i86pc/$ISADIR/boot_archive
 *
 * which may be specified exactly as either of:
 *
 * module /platform/i86pc/boot_archive
 * module /platform/i86pc/amd64/boot_archive
 *
 * Under multiboot, the failsafe is:
 *
 * module /boot/x86.miniroot-safe
 *
 * Under dboot, the failsafe is:
 *
 * module$ /boot/$ISADIR/x86.miniroot-safe
 *
 * which may be specified exactly as either of:
 *
 * module /boot/x86.miniroot-safe
 * module /boot/amd64/x86.miniroot-safe
 */
static error_t
cvt_module_line(line_t *line, entry_t *entry)
{
    const char      *fcn = "cvt_module_line()";

    BAM_DPRINTF(("%s: entered. arg: %s\n", fcn, line->line));

    /*
     * We only convert multiboot to dboot and nothing else
     */
    if (!(entry->flags & BAM_ENTRY_MULTIBOOT)) {
        BAM_DPRINTF(("%s: not MULTIBOOT, not converting\n", fcn));
        return (BAM_SUCCESS);
    }

    if (entry->flags & BAM_ENTRY_FAILSAFE) {
        if (strcmp(line->arg, FAILSAFE_ARCHIVE) == 0) {
            BAM_DPRINTF(("%s: failsafe module line needs no "
                "conversion: %s\n", fcn, line->arg));
            BAM_DPRINTF(("%s: returning SUCCESS\n", fcn));
            return (BAM_SUCCESS);
        }
    } else if (strcmp(line->arg, MULTIBOOT_ARCHIVE) != 0) {
        bam_error(_("module command on line %d not recognized.\n"),
            line->lineNum);
        BAM_DPRINTF(("%s: returning FAILURE\n", fcn));
        return (BAM_MSG);
    }

    free(line->cmd);
    free(line->arg);
    line->cmd = s_strdup(menu_cmds[MODULE_DOLLAR_CMD]);

    line->arg = s_strdup(entry->flags & BAM_ENTRY_FAILSAFE ?
        FAILSAFE_ARCHIVE : DIRECT_BOOT_ARCHIVE);

    update_line(line);
    BAM_DPRINTF(("%s: converted module line is: %s\n", fcn, line->line));
    BAM_DPRINTF(("%s: returning SUCCESS\n", fcn));
    return (BAM_SUCCESS);
}

static void
bam_warn_hand_entries(menu_t *mp, char *osroot)
{
    int     hand_num;
    int     hand_max;
    int     *hand_list;
    int     i;
    entry_t     *entry;
    const char  *fcn = "bam_warn_hand_entries()";

    if (bam_force) {
        /*
         * No warning needed, we are automatically converting
         * the "hand" entries
         */
        BAM_DPRINTF(("%s: force specified, no warnings about hand "
            "entries\n",  fcn));
        return;
    }

    hand_num = 0;
    hand_max = BAM_ENTRY_NUM;
    hand_list = s_calloc(1, hand_max);

    for (entry = mp->entries; entry; entry = entry->next) {
        if (entry->flags & (BAM_ENTRY_BOOTADM|BAM_ENTRY_LU))
            continue;
        BAM_DPRINTF(("%s: found hand entry #: %d\n", fcn,
            entry->entryNum));
        if (++hand_num > hand_max) {
            hand_max *= 2;
            hand_list = s_realloc(hand_list,
                hand_max * sizeof (int));
        }
        hand_list[hand_num - 1] = entry->entryNum;
    }

    bam_error(_("bootadm(1M) will only upgrade GRUB menu entries added "
        "by \nbootadm(1M) or lu(1M). The following entries on %s will "
        "not be upgraded.\nFor details on manually updating entries, "
        "see %s\n"), osroot, MENU_URL(osroot));
    bam_print_stderr("Entry Number%s: ", (hand_num > 1) ?
        "s" : "");
    for (i = 0; i < hand_num; i++) {
        bam_print_stderr("%d ", hand_list[i]);
    }
    bam_print_stderr("\n");
}

static entry_t *
find_matching_entry(
    entry_t *estart,
    char *grubsign,
    char *grubroot,
    int root_opt)
{
    entry_t     *entry;
    line_t      *line;
    char        opt[10];
    const char  *fcn = "find_matching_entry()";

    assert(grubsign);
    assert(root_opt == 0 || root_opt == 1);

    (void) snprintf(opt, sizeof (opt), "%d", root_opt);
    BAM_DPRINTF(("%s: entered. args: %s %s %s\n", fcn, grubsign,
        grubroot, opt));

    for (entry = estart; entry; entry = entry->next) {

        if (!(entry->flags & (BAM_ENTRY_BOOTADM|BAM_ENTRY_LU)) &&
            !bam_force) {
            BAM_DPRINTF(("%s: skipping hand entry #: %d\n",
                fcn, entry->entryNum));
            continue;
        }

        if (entry->flags & BAM_ENTRY_ROOT) {
            for (line = entry->start; line; line = line->next) {
                if (line->cmd == NULL || line->arg == NULL) {
                    if (line == entry->end) {
                        BAM_DPRINTF(("%s: entry has "
                            "ended\n", fcn));
                        break;
                    } else {
                        BAM_DPRINTF(("%s: skipping "
                            "NULL line\n", fcn));
                        continue;
                    }
                }
                if (strcmp(line->cmd, menu_cmds[ROOT_CMD])
                    == 0 && strcmp(line->arg, grubroot) == 0) {
                    BAM_DPRINTF(("%s: found matching root "
                        "line: %s,%s\n", fcn,
                        line->line, grubsign));
                    return (entry);
                }
                if (line == entry->end) {
                    BAM_DPRINTF(("%s: entry has ended\n",
                        fcn));
                    break;
                }
            }
        } else if (entry->flags & BAM_ENTRY_FINDROOT) {
            for (line = entry->start; line; line = line->next) {
                if (line->cmd == NULL || line->arg == NULL) {
                    if (line == entry->end) {
                        BAM_DPRINTF(("%s: entry has "
                            "ended\n", fcn));
                        break;
                    } else {
                        BAM_DPRINTF(("%s: skipping "
                            "NULL line\n", fcn));
                        continue;
                    }
                }
                if (strcmp(line->cmd, menu_cmds[FINDROOT_CMD])
                    == 0 && strcmp(line->arg, grubsign) == 0) {
                    BAM_DPRINTF(("%s: found matching "
                        "findroot line: %s,%s\n", fcn,
                        line->line, grubsign));
                    return (entry);
                }
                if (line == entry->end) {
                    BAM_DPRINTF(("%s: entry has ended\n",
                        fcn));
                    break;
                }
            }
        } else if (root_opt) {
            /* Neither root nor findroot */
            BAM_DPRINTF(("%s: no root or findroot and root is "
                "opt: %d\n", fcn, entry->entryNum));
            return (entry);
        }
    }

    BAM_DPRINTF(("%s: no matching entry found\n", fcn));
    return (NULL);
}

/*
 * The following is a set of routines that attempt to convert the
 * menu entries for the supplied osroot into a format compatible
 * with the GRUB installation on osroot.
 *
 * Each of these conversion routines make no assumptions about
 * the current state of the menu entry, it does its best to
 * convert the menu entry to the new state. In the process
 * we may either upgrade or downgrade.
 *
 * We don't make any heroic efforts at conversion. It is better
 * to be conservative and bail out at the first sign of error. We will
 * in such cases, point the user at the knowledge-base article
 * so that they can upgrade manually.
 */
static error_t
bam_add_findroot(menu_t *mp, char *grubsign, char *grubroot, int root_opt)
{
    entry_t     *entry;
    line_t      *line;
    line_t      *newlp;
    int     update_num;
    char        linebuf[PATH_MAX];
    const char  *fcn = "bam_add_findroot()";

    update_num = 0;

    bam_print(_("converting entries to findroot...\n"));

    entry = find_matching_entry(mp->entries, grubsign, grubroot, root_opt);
    while (entry != NULL) {
        if (entry->flags & BAM_ENTRY_FINDROOT) {
            /* already converted */
            BAM_DPRINTF(("%s: entry %d already converted to "
                "findroot\n", fcn, entry->entryNum));
            entry = find_matching_entry(entry->next, grubsign,
                grubroot, root_opt);
            continue;
        }
        for (line = entry->start; line; line = line->next) {
            if (line->cmd == NULL || line->arg == NULL) {
                if (line == entry->end) {
                    BAM_DPRINTF(("%s: entry has ended\n",
                        fcn));
                    break;
                } else {
                    BAM_DPRINTF(("%s: skipping NULL line\n",
                        fcn));
                    continue;
                }
            }
            if (strcmp(line->cmd, menu_cmds[TITLE_CMD]) == 0) {
                newlp = s_calloc(1, sizeof (line_t));
                newlp->cmd = s_strdup(menu_cmds[FINDROOT_CMD]);
                newlp->sep = s_strdup(" ");
                newlp->arg = s_strdup(grubsign);
                (void) snprintf(linebuf, sizeof (linebuf),
                    "%s%s%s", newlp->cmd, newlp->sep,
                    newlp->arg);
                newlp->line = s_strdup(linebuf);
                bam_add_line(mp, entry, line, newlp);
                update_num = 1;
                entry->flags &= ~BAM_ENTRY_ROOT;
                entry->flags |= BAM_ENTRY_FINDROOT;
                BAM_DPRINTF(("%s: added findroot line: %s\n",
                    fcn, newlp->line));
                line = newlp;
            }
            if (strcmp(line->cmd, menu_cmds[ROOT_CMD]) == 0) {
                BAM_DPRINTF(("%s: freeing root line: %s\n",
                    fcn, line->line));
                unlink_line(mp, line);
                line_free(line);
            }
            if (line == entry->end) {
                BAM_DPRINTF(("%s: entry has ended\n", fcn));
                break;
            }
        }
        entry = find_matching_entry(entry->next, grubsign, grubroot,
            root_opt);
    }

    if (update_num) {
        BAM_DPRINTF(("%s: updated numbering\n", fcn));
        update_numbering(mp);
    }

    BAM_DPRINTF(("%s: returning SUCCESS\n", fcn));
    return (BAM_SUCCESS);
}

static error_t
bam_add_hv(menu_t *mp, char *grubsign, char *grubroot, int root_opt)
{
    entry_t     *entry;
    const char  *fcn = "bam_add_hv()";

    bam_print(_("adding xVM entries...\n"));

    entry = find_matching_entry(mp->entries, grubsign, grubroot, root_opt);
    while (entry != NULL) {
        if (entry->flags & BAM_ENTRY_HV) {
            BAM_DPRINTF(("%s: entry %d already converted to "
                "xvm HV\n", fcn, entry->entryNum));
            return (BAM_SUCCESS);
        }
        entry = find_matching_entry(entry->next, grubsign, grubroot,
            root_opt);
    }

    (void) add_boot_entry(mp, NEW_HV_ENTRY, grubsign, XEN_MENU,
        XEN_KERNEL_MODULE_LINE, DIRECT_BOOT_ARCHIVE, NULL);

    BAM_DPRINTF(("%s: added xVM HV entry via add_boot_entry()\n", fcn));

    update_numbering(mp);

    BAM_DPRINTF(("%s: returning SUCCESS\n", fcn));

    return (BAM_SUCCESS);
}

static error_t
bam_add_dboot(
    menu_t *mp,
    char *osroot,
    char *grubsign,
    char *grubroot,
    int root_opt)
{
    int     msg = 0;
    entry_t     *entry;
    line_t      *line;
    error_t     ret;
    const char  *fcn = "bam_add_dboot()";

    bam_print(_("converting entries to dboot...\n"));

    entry = find_matching_entry(mp->entries, grubsign, grubroot, root_opt);
    while (entry != NULL) {
        for (line = entry->start; line; line = line->next) {
            if (line->cmd == NULL || line->arg == NULL) {
                if (line == entry->end) {
                    BAM_DPRINTF(("%s: entry has ended\n",
                        fcn));
                    break;
                } else {
                    BAM_DPRINTF(("%s: skipping NULL line\n",
                        fcn));
                    continue;
                }
            }

            /*
             * If we have a kernel$ command, assume it
             * is dboot already.  If it is not a dboot
             * entry, something funny is going on and
             * we will leave it alone
             */
            if (strcmp(line->cmd, menu_cmds[KERNEL_CMD]) == 0) {
                ret = cvt_kernel_line(line, osroot, entry);
                INJECT_ERROR1("ADD_DBOOT_KERN_ERR",
                    ret = BAM_ERROR);
                INJECT_ERROR1("ADD_DBOOT_KERN_MSG",
                    ret = BAM_MSG);
                if (ret == BAM_ERROR) {
                    BAM_DPRINTF(("%s: cvt_kernel_line() "
                        "failed\n", fcn));
                    return (ret);
                } else if (ret == BAM_MSG) {
                    msg = 1;
                    BAM_DPRINTF(("%s: BAM_MSG returned "
                        "from cvt_kernel_line()\n", fcn));
                }
            }
            if (strcmp(line->cmd, menu_cmds[MODULE_CMD]) == 0) {
                ret = cvt_module_line(line, entry);
                INJECT_ERROR1("ADD_DBOOT_MOD_ERR",
                    ret = BAM_ERROR);
                INJECT_ERROR1("ADD_DBOOT_MOD_MSG",
                    ret = BAM_MSG);
                if (ret == BAM_ERROR) {
                    BAM_DPRINTF(("%s: cvt_module_line() "
                        "failed\n", fcn));
                    return (ret);
                } else if (ret == BAM_MSG) {
                    BAM_DPRINTF(("%s: BAM_MSG returned "
                        "from cvt_module_line()\n", fcn));
                    msg = 1;
                }
            }

            if (line == entry->end) {
                BAM_DPRINTF(("%s: entry has ended\n", fcn));
                break;
            }
        }
        entry = find_matching_entry(entry->next, grubsign, grubroot,
            root_opt);
    }

    ret = msg ? BAM_MSG : BAM_SUCCESS;
    BAM_DPRINTF(("%s: returning ret = %d\n", fcn, ret));
    return (ret);
}

/*ARGSUSED*/
error_t
upgrade_menu(menu_t *mp, char *osroot, char *menu_root)
{
    char        *osdev;
    char        *grubsign;
    char        *grubroot;
    int     ret1;
    int     ret2;
    int     ret3;
    const char  *fcn = "upgrade_menu()";

    assert(osroot);
    assert(menu_root);

    BAM_DPRINTF(("%s: entered. args: %s %s\n", fcn, osroot, menu_root));

    /*
     * We only support upgrades. Xen may not be present
     * on smaller metaclusters so we don't check for that.
     */
    if (bam_is_findroot != BAM_FINDROOT_PRESENT ||
        bam_direct != BAM_DIRECT_DBOOT) {
        bam_error(_("automated downgrade of GRUB menu to older "
            "version not supported.\n"));
        return (BAM_ERROR);
    }

    /*
     * First get the GRUB signature
     */
    osdev = get_special(osroot);
    INJECT_ERROR1("UPGRADE_OSDEV", osdev = NULL);
    if (osdev == NULL) {
        bam_error(_("cant find special file for mount-point %s\n"),
            osroot);
        return (BAM_ERROR);
    }

    grubsign = get_grubsign(osroot, osdev);
    INJECT_ERROR1("UPGRADE_GRUBSIGN", grubsign = NULL);
    if (grubsign == NULL) {
        free(osdev);
        bam_error(_("cannot find GRUB signature for %s\n"), osroot);
        return (BAM_ERROR);
    }

    /* not fatal if we can't get grubroot */
    grubroot = get_grubroot(osroot, osdev, menu_root);
    INJECT_ERROR1("UPGRADE_GRUBROOT", grubroot = NULL);

    free(osdev);

    ret1 = bam_add_findroot(mp, grubsign,
        grubroot, root_optional(osroot, menu_root));
    INJECT_ERROR1("UPGRADE_ADD_FINDROOT", ret1 = BAM_ERROR);
    if (ret1 == BAM_ERROR)
        goto abort;

    if (bam_is_hv == BAM_HV_PRESENT) {
        ret2 = bam_add_hv(mp, grubsign, grubroot,
            root_optional(osroot, menu_root));
        INJECT_ERROR1("UPGRADE_ADD_HV", ret2 = BAM_ERROR);
        if (ret2 == BAM_ERROR)
            goto abort;
    } else
        ret2 = BAM_SUCCESS;

    ret3 = bam_add_dboot(mp, osroot, grubsign,
        grubroot, root_optional(osroot, menu_root));
    INJECT_ERROR1("UPGRADE_ADD_DBOOT", ret3 = BAM_ERROR);
    if (ret3 == BAM_ERROR)
        goto abort;

    if (ret1 == BAM_MSG || ret2 == BAM_MSG || ret3 == BAM_MSG) {
        bam_error(_("one or more GRUB menu entries were not "
            "automatically upgraded\nFor details on manually "
            "updating entries, see %s\n"), MENU_URL(osroot));
    } else {
        bam_warn_hand_entries(mp, osroot);
    }

    free(grubsign);

    BAM_DPRINTF(("%s: returning ret = %d\n", fcn, BAM_WRITE));
    return (BAM_WRITE);

abort:
    free(grubsign);
    bam_error(_("error upgrading GRUB menu entries on %s. Aborting.\n"
        "For details on manually updating entries, see %s\n"), osroot,
        MENU_URL(osroot));
    return (BAM_ERROR);
}