libgrubmgmt/common/libgrub_fs.c

	libgrub_fs.c revision 753a6d457b330b1b29b2d3eefcd0831116ce950d
/*
 * 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.
 */

/*
 * This file contains all the functions that manipualte the file
 * system where the GRUB menu resides.
 */
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <strings.h>
#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/mntent.h>
#include <sys/mnttab.h>
#include <sys/fs/ufs_mount.h>
#include <sys/dktp/fdisk.h>
#include <libfstyp.h>

#include "libgrub_impl.h"

static int
slice_match(const char *physpath, int slice)
{
    const char *pos;

    return ((pos = strrchr(physpath, slice)) == NULL ||
        pos[1] != 0 || pos[-1] != ':');
}

/*
 * Returns zero if path contains ufs
 */
static int
slice_ufs(const char *path)
{
    int fd, ret;
    const char *id;
    fstyp_handle_t hdl;

    fd = open(path, O_RDONLY);
    if ((ret = fstyp_init(fd, 0, NULL, &hdl)) == 0) {
        ret = fstyp_ident(hdl, "ufs", &id);
        fstyp_fini(hdl);
    }
    (void) close(fd);
    return (ret);
}


static int
get_sol_prtnum(const char *physpath)
{
    int i, fd;
    char *pos;
    size_t sz;
    struct mboot *mb;
    struct ipart *ipart;
    char boot_sect[512];
    char rdev[MAXNAMELEN];

    (void) snprintf(rdev, sizeof (rdev), "/devices%s,raw", physpath);

    if ((pos = strrchr(rdev, ':')) == NULL)
        return (PRTNUM_INVALID);

    pos[1] = SLCNUM_WHOLE_DISK;

    fd = open(rdev, O_RDONLY);
    sz = read(fd, boot_sect, sizeof (boot_sect));
    (void) close(fd);

    if (sz != sizeof (boot_sect))
        return (PRTNUM_INVALID);

    /* parse fdisk table */
    mb = (struct mboot *)(uintptr_t)boot_sect;
    ipart = (struct ipart *)(uintptr_t)mb->parts;
    for (i = 0; i < FD_NUMPART; ++i) {
        if (ipart[i].systid == SUNIXOS || ipart[i].systid == SUNIXOS2)
            return (i);
    }
    return (PRTNUM_INVALID);
}

/*
 * Get physpath, topfs and bootfs for ZFS root dataset.
 * Return 0 on success, non-zero (not errno) on failure.
 */
static int
get_zfs_root(zfs_handle_t *zfh, grub_fs_t *fs, grub_root_t *root)
{
    int ret;
    zpool_handle_t *zph;
    const char *name;

    if (zfs_get_type(zfh) != ZFS_TYPE_FILESYSTEM ||
        (name = zfs_get_name(zfh)) == NULL ||
        (zph = zpool_open(fs->gf_lzfh, name)) == NULL)
        return (-1);

    if ((ret = zpool_get_physpath(zph, root->gr_physpath,
        sizeof (root->gr_physpath))) == 0 &&
        (ret = zpool_get_prop(zph, ZPOOL_PROP_BOOTFS,
        root->gr_fs[GRBM_ZFS_BOOTFS].gfs_dev,
        sizeof (root->gr_fs[GRBM_ZFS_BOOTFS].gfs_dev), NULL)) == 0) {

        (void) strlcpy(root->gr_fs[GRBM_ZFS_TOPFS].gfs_dev, name,
            sizeof (root->gr_fs[GRBM_ZFS_TOPFS].gfs_dev));
        (void) grub_fsd_get_mountp(root->gr_fs + GRBM_ZFS_BOOTFS,
            MNTTYPE_ZFS);
        (void) grub_fsd_get_mountp(root->gr_fs + GRBM_ZFS_TOPFS,
            MNTTYPE_ZFS);
    }

    zpool_close(zph);
    return (ret);
}

/*
 * On entry physpath parameter supposed to contain:
 * <disk_physpath>[<space><disk_physpath>]*.
 * Retireives first <disk_physpath> that matches both partition and slice.
 * If any partition and slice is acceptable, first <disk_physpath> is returned.
 */
static int
get_one_physpath(char *physpath, uint_t prtnum, uint_t slcnum)
{
    int ret;
    char *tmp, *tok;

    if (!IS_SLCNUM_VALID(slcnum) && !IS_PRTNUM_VALID(prtnum)) {
        (void) strtok(physpath, " ");
        return (0);
    }

    if ((tmp = strdup(physpath)) == NULL)
        return (errno);

    ret = ENODEV;
    for (tok = strtok(tmp, " "); tok != NULL; tok = strtok(NULL, " ")) {
        if ((ret = (slice_match(tok, slcnum) != 0 ||
            get_sol_prtnum(tok) != prtnum)) == 0) {
            (void) strcpy(physpath, tok);
            break;
        }
    }

    free(tmp);
    return (ret);
}

static int
zfs_bootsign(zfs_handle_t *zfh, void *data)
{
    grub_barg_t *barg;
    grub_menu_t *menu;
    struct stat st;
    char path[MAXPATHLEN];

    barg = (grub_barg_t *)data;
    menu = barg->gb_entry->ge_menu;

    do {
        if (get_zfs_root(zfh, &menu->gm_fs, &barg->gb_root) != 0 ||
            get_one_physpath(barg->gb_root.gr_physpath, barg->gb_prtnum,
            barg->gb_slcnum) != 0)
            break;

        /*
         * if top zfs dataset is not mounted, mount it now
         */
        if (barg->gb_root.gr_fs[GRBM_ZFS_TOPFS].gfs_mountp[0] == 0) {
            if (grub_fsd_mount_tmp(barg->gb_root.gr_fs +
                GRBM_ZFS_TOPFS, MNTTYPE_ZFS) != 0)
                break;
        }

        /* check that bootsign exists and it is a regular file */
        (void) snprintf(path, sizeof (path), "%s%s",
            barg->gb_root.gr_fs[GRBM_ZFS_TOPFS].gfs_mountp,
            barg->gb_bootsign);

        if (lstat(path, &st) != 0 || S_ISREG(st.st_mode) == 0 ||
            (st.st_mode & S_IRUSR) == 0)
            break;

        (void) strlcpy(barg->gb_root.gr_fstyp, MNTTYPE_ZFS,
            sizeof (barg->gb_root.gr_fstyp));
        barg->gb_walkret = 0;
    /* LINTED: E_CONSTANT_CONDITION */
    } while (0);

    grub_fsd_umount_tmp(barg->gb_root.gr_fs + GRBM_ZFS_TOPFS);
    zfs_close(zfh);

    /* return non-zero to terminate the walk */
    return (barg->gb_walkret == 0);
}

static int
get_devlink(di_devlink_t dl, void *arg)
{
    const char *path;
    grub_barg_t *barg;

    barg = (grub_barg_t *)arg;
    if ((path = di_devlink_path(dl)) != NULL)
        (void) strlcpy(barg->gb_root.gr_fs[GRBM_UFS].gfs_dev, path,
            sizeof (barg->gb_root.gr_fs[GRBM_UFS].gfs_dev));
    return (DI_WALK_TERMINATE);
}

static int
ufs_bootsign_check(grub_barg_t *barg)
{
    int ret;
    struct stat st;
    grub_menu_t *mp;
    char path[MAXPATHLEN];

    mp = barg->gb_entry->ge_menu;

    /* get /dev/dsk link */
    if (di_devlink_walk(mp->gm_fs.gf_dvlh, "^dsk/",
        barg->gb_root.gr_physpath, DI_PRIMARY_LINK, barg, get_devlink) != 0)
        return (errno);
    /*
     * if disk is not mounted, mount it now
     */
    if (grub_fsd_get_mountp(barg->gb_root.gr_fs + GRBM_UFS,
        MNTTYPE_UFS) != 0) {
        if ((ret =
            slice_ufs(barg->gb_root.gr_fs[GRBM_UFS].gfs_dev)) != 0 ||
            (ret = grub_fsd_mount_tmp(barg->gb_root.gr_fs + GRBM_UFS,
            MNTTYPE_UFS)) != 0)
            return (ret);
    }

    (void) snprintf(path, sizeof (path), "%s%s",
        barg->gb_root.gr_fs[GRBM_UFS].gfs_mountp, barg->gb_bootsign);

    if (lstat(path, &st) == 0 && S_ISREG(st.st_mode) &&
        (st.st_mode & S_IRUSR) != 0) {
        barg->gb_walkret = 0;
        (void) strlcpy(barg->gb_root.gr_fstyp, MNTTYPE_UFS,
            sizeof (barg->gb_root.gr_fstyp));
    }

    grub_fsd_umount_tmp(barg->gb_root.gr_fs + GRBM_UFS);
    return (barg->gb_walkret);
}

static int
ufs_bootsign(di_node_t node, di_minor_t minor, void *arg)
{
    uint_t prtnum;
    char *name, *path;
    grub_barg_t *barg;

    barg = (grub_barg_t *)arg;

    if (di_minor_spectype(minor) != S_IFBLK)
        return (DI_WALK_CONTINUE);

    name = di_minor_name(minor);
    if (name[0] != barg->gb_slcnum || name[1] != 0)
        return (DI_WALK_CONTINUE);

    path = di_devfs_path(node);
    (void) snprintf(barg->gb_root.gr_physpath,
        sizeof (barg->gb_root.gr_physpath), "%s:%c", path, barg->gb_slcnum);
    di_devfs_path_free(path);

    prtnum = get_sol_prtnum(barg->gb_root.gr_physpath);
    if (!IS_PRTNUM_VALID(prtnum))
        return (DI_WALK_CONTINUE);

    /*
     * check only specified partition, slice
     */

    if (IS_PRTNUM_VALID(barg->gb_prtnum)) {
        if (prtnum != barg->gb_prtnum || ufs_bootsign_check(barg) != 0)
            return (DI_WALK_CONTINUE);
        return (DI_WALK_TERMINATE);
    }

    /*
     * Walk through all slices in found solaris partition
     */

    barg->gb_prtnum = prtnum;
    minor = DI_MINOR_NIL;

    while ((minor = di_minor_next(node, minor)) != DI_MINOR_NIL) {

        if (di_minor_spectype(minor) != S_IFBLK)
            continue;

        name = di_minor_name(minor);
        if (!IS_SLCNUM_VALID(name[0]) || name[1] != 0)
            continue;

        barg->gb_slcnum = name[0];
        path = strrchr(barg->gb_root.gr_physpath, ':');
        path[1] = barg->gb_slcnum;

        if (ufs_bootsign_check(barg) == 0)
            return (DI_WALK_TERMINATE);
    }

    barg->gb_prtnum = (uint_t)PRTNUM_INVALID;
    barg->gb_slcnum = (uint_t)SLCNUM_WHOLE_DISK;
    return (DI_WALK_CONTINUE);
}

/*
 * Differs from what GRUB is doing: GRUB searchs through all disks seen by bios
 * for bootsign, if bootsign is found on ufs slice GRUB sets it as a root,
 * if on zfs, then GRUB uses zfs slice as root only if bootsign wasn't found
 * on other slices.
 * That function first searches through all top datasets of active zpools,
 * then if bootsign still not found walks through all disks and tries to
 * find ufs slice with the bootsign.
 */
int
grub_find_bootsign(grub_barg_t *barg)
{
    grub_menu_t *mp;
    mp = barg->gb_entry->ge_menu;

    /* try to find bootsign over zfs pools */
    barg->gb_walkret = EG_BOOTSIGN;
    (void) zfs_iter_root(mp->gm_fs.gf_lzfh, zfs_bootsign, barg);

    /* try ufs now */
    if (barg->gb_walkret != 0 && di_walk_minor(mp->gm_fs.gf_diroot,
        DDI_NT_BLOCK, 0, barg, ufs_bootsign) != 0)
        return (errno);

    return (barg->gb_walkret);
}

/*
 * Get current root file system.
 * Return 0 on success, errno code on failure.
 */
int
grub_current_root(grub_fs_t *fs, grub_root_t *root)
{
    int rc = 0;
    FILE *fp = NULL;
    char *name = NULL;
    zfs_handle_t *zfh = NULL;
    struct mnttab mp = {0};
    struct mnttab mpref = {0};
    char buf[MAXNAMELEN] = {0};

    mpref.mnt_mountp = "/";

    if ((fp = fopen(MNTTAB, "r")) == NULL)
        return (errno);

    /*
     * getmntany returns non-zero for failure, and sets errno
     */
    rc = getmntany(fp, &mp, &mpref);
    if (rc != 0)
        rc = errno;

    (void) fclose(fp);

    if (rc != 0)
        return (rc);

    (void) strlcpy(root->gr_fstyp, mp.mnt_fstype, sizeof (root->gr_fstyp));

    if (strcmp(root->gr_fstyp, MNTTYPE_ZFS) == 0) {

        (void) strlcpy(buf, mp.mnt_special, sizeof (buf));
        if ((name = strtok(buf, "/")) == NULL)
            return (EG_CURROOT);

        if ((zfh = zfs_open(fs->gf_lzfh, name, ZFS_TYPE_FILESYSTEM)) ==
            NULL)
            return (EG_OPENZFS);

        /*
         * get_zfs_root returns non-zero on failure, not
         * errno.
         */
        if (get_zfs_root(zfh, fs, root))
            rc = EG_CURROOT;

        zfs_close(zfh);

    } else if (strcmp(mp.mnt_fstype, MNTTYPE_UFS) == 0) {
        (void) strlcpy(root->gr_fs[GRBM_UFS].gfs_dev, mp.mnt_special,
            sizeof (root->gr_fs[GRBM_UFS].gfs_dev));
        (void) strlcpy(root->gr_fs[GRBM_UFS].gfs_mountp, mp.mnt_mountp,
            sizeof (root->gr_fs[GRBM_UFS].gfs_mountp));
    } else {
        rc = EG_UNKNOWNFS;
    }

    return (rc);
}

grub_fsdesc_t *
grub_get_rootfsd(const grub_root_t *root)
{
    grub_fsdesc_t *fsd = NULL;

    assert(root);
    if (strcmp(MNTTYPE_UFS, root->gr_fstyp) == 0)
        fsd = (grub_fsdesc_t *)root->gr_fs + GRBM_UFS;
    else if (strcmp(MNTTYPE_ZFS, root->gr_fstyp) == 0)
        fsd = (grub_fsdesc_t *)root->gr_fs + GRBM_ZFS_BOOTFS;

    return (fsd);
}

/*
 * Gets file systems mount point if any.
 * Return 0 if filesystem is mounted, errno on failure.
 */
int
grub_fsd_get_mountp(grub_fsdesc_t *fsd, char *fstyp)
{
    int rc;
    FILE *fp = NULL;
    struct mnttab mp = {0};
    struct mnttab mpref = {0};

    fsd->gfs_mountp[0] = 0;

    if ((fp = fopen(MNTTAB, "r")) == NULL)
        return (errno);

    mpref.mnt_special = fsd->gfs_dev;
    mpref.mnt_fstype = fstyp;

    if ((rc = getmntany(fp, &mp, &mpref)) == 0)
        (void) strlcpy(fsd->gfs_mountp, mp.mnt_mountp,
            sizeof (fsd->gfs_mountp));
    else
        rc = EG_GETMNTTAB;

    (void) fclose(fp);
    return (rc);
}

static const char tmp_mountp[] = "/tmp/.libgrubmgmt.%s.XXXXXX";

/*
 * Mount file system at tmp_mountp.
 * Return 0 on success, errno on failure.
 */
int
grub_fsd_mount_tmp(grub_fsdesc_t *fsd, const char *fstyp)
{
    const char *pos;
    void *data = NULL;
    int dtsz = 0;
    struct ufs_args ufs_args = {UFSMNT_LARGEFILES};
    char mntopts[MNT_LINE_MAX] = "";
    int rc = 0;

    assert(fsd);
    assert(!fsd->gfs_is_tmp_mounted);

    fsd->gfs_mountp[0] = 0;

    if (strcmp(fstyp, MNTTYPE_UFS) == 0) {
        (void) strlcpy(mntopts, MNTOPT_LARGEFILES, sizeof (mntopts));
        data = &ufs_args;
        dtsz = sizeof (ufs_args);
    } else if (strcmp(fstyp, MNTTYPE_ZFS) != 0) {
        return (EG_UNKNOWNFS);
    }

    /* construct name for temporary mount point */
    pos = strrchr(fsd->gfs_dev, '/');
    pos = (pos == NULL) ? fsd->gfs_dev : pos + 1;

    (void) snprintf(fsd->gfs_mountp, sizeof (fsd->gfs_mountp),
        tmp_mountp, pos);
    if (mkdtemp(fsd->gfs_mountp) != NULL) {
        if ((rc = mount(fsd->gfs_dev, fsd->gfs_mountp,
            MS_DATA | MS_OPTIONSTR | MS_RDONLY,
            fstyp, data, dtsz, mntopts, sizeof (mntopts))) != 0) {
            /*
             * mount failed, collect errno and remove temp dir
             */
            rc = errno;
            (void) rmdir(fsd->gfs_mountp);
        }
    } else {
        rc = errno;
    }

    if (rc != 0)
        fsd->gfs_mountp[0] = 0;

    /*
     * Note that valid values for gfs_is_tmp_mounted are 0,1.
     * Any other value indicates that something bad happened.
     * Probably grub_fsd_umount_tmp() wasn't called or didn't
     * work as expected.
     */
    fsd->gfs_is_tmp_mounted += (rc == 0);
    return (rc);
}

/*
 * Unmount file system at tmp_mountp.
 */
void
grub_fsd_umount_tmp(grub_fsdesc_t *fsd)
{
    if (fsd == NULL)
        return;

    if (fsd->gfs_is_tmp_mounted) {
        if (fsd->gfs_mountp[0] != 0) {
            (void) umount2(fsd->gfs_mountp, 0);
            (void) rmdir(fsd->gfs_mountp);
            fsd->gfs_mountp[0] = 0;
        }
        fsd->gfs_is_tmp_mounted = 0;
    }
}