/*-
 * Copyright (c) 1999 Michael Smith
 * All rights reserved.
 * Copyright (c) 1999 Poul-Henning Kamp
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      $FreeBSD: src/sys/kern/vfs_conf.c,v 1.49.2.5 2003/01/07 11:56:53 joerg Exp $
 */

/*
 * Locate and mount the root filesystem.
 *
 * The root filesystem is detailed in the kernel environment variable
 * vfs.root.mountfrom, which is expected to be in the general format
 *
 * <vfsname>:[<path>]
 * vfsname   := the name of a VFS known to the kernel and capable
 *              of being mounted as root
 * path      := disk device name or other data used by the filesystem
 *              to locate its physical store
 *
 */

#include "opt_rootdevname.h"

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/reboot.h>
#include <sys/diskslice.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/kbio.h>
#include <sys/device.h>
#include <sys/disk.h>
#include <sys/namecache.h>
#include <sys/paths.h>
#include <sys/thread2.h>
#include <sys/nlookup.h>
#include <sys/devfs.h>
#include <sys/sysctl.h>

#include "opt_ddb.h"
#ifdef DDB
#include <ddb/ddb.h>
#endif

MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");

#define ROOTNAME        "root_device"

struct vnode    *rootvnode;
struct nchandle rootnch;

/* 
 * The root specifiers we will try if RB_CDROM is specified.  Note that
 * with DEVFS we do not use the compatibility slice's whole-disk 'c'
 * partition.  Instead we just use the whole disk, e.g. cd0 or cd0s0.
 */
static char *cdrom_rootdevnames[] = {
        "cd9660:cd0",   /* SCSI (including AHCI and SILI) */
        "cd9660:acd0",  /* NATA */
        "cd9660:cd1",   /* SCSI (including AHCI and SILI) */
        "cd9660:acd1",  /* NATA */
        "cd9660:cd8",   /* USB */
        "cd9660:cd9",   /* USB */
        NULL
};

int vfs_mountroot_devfs(void);
static void     vfs_mountroot(void *junk);
static int      vfs_mountroot_try(const char *mountfrom);
static int      vfs_mountroot_ask(void);
static int      get_line(char *cp, int limit);

/* legacy find-root code */
char            *rootdevnames[2] = {NULL, NULL};
static int      setrootbyname(char *name);

SYSINIT(mountroot, SI_SUB_MOUNT_ROOT, SI_ORDER_SECOND, vfs_mountroot, NULL);

/*
 * Delay before mounting root, in milliseconds.  Gives better granularity
 * for non-CAM kern confs than the old seconds-based tunable it supersedes.
 */
static int wakedelay_ms = 2000; /* delay before mounting root in milliseconds */
TUNABLE_INT("vfs.root.wakedelay_ms", &wakedelay_ms);

/*
 * Find and mount the root filesystem
 */
static void
vfs_mountroot(void *junk)
{
        cdev_t  save_rootdev = rootdev;
        int     i;
        int     dummy;

        /*
         * Make sure all disk devices created so far have also been probed,
         * and also make sure that the newly created device nodes for
         * probed disks are ready, too.
         *
         * Messages can fly around here so get good synchronization
         * coverage.
         *
         * XXX - Delay some more (default: 2s) to help drivers which pickup
         *       devices asynchronously and are not caught by CAM's initial
         *       probe.
         */
        sync_devs();

        /*
         * Delay in milliseconds via vfs.root.wakedelay_ms.  The +1 tick
         * avoids a 0 timeout, which tsleep() would treat as "sleep forever".
         */
        tsleep(&dummy, 0, "syncer", hz * wakedelay_ms / 1000 + 1);


        /* 
         * The root filesystem information is compiled in, and we are
         * booted with instructions to use it.
         */
#ifdef ROOTDEVNAME
        if ((boothowto & RB_DFLTROOT) && 
            !vfs_mountroot_try(ROOTDEVNAME))
                return;
#endif
        /* 
         * We are booted with instructions to prompt for the root filesystem,
         * or to use the compiled-in default when it doesn't exist.
         */
        if (boothowto & (RB_DFLTROOT | RB_ASKNAME)) {
                if (!vfs_mountroot_ask())
                        return;
        }

        /*
         * We've been given the generic "use CDROM as root" flag.  This is
         * necessary because one media may be used in many different
         * devices, so we need to search for them.
         */
        if (boothowto & RB_CDROM) {
                for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
                        if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
                                return;
                }
        }

        /*
         * Try to use the value read by the loader from /etc/fstab, or
         * supplied via some other means.  This is the preferred 
         * mechanism.
         */
        if (!vfs_mountroot_try(kgetenv("vfs.root.mountfrom")))
                return;

        /*
         * If a vfs set rootdev, try it (XXX VINUM HACK!)
         */
        if (save_rootdev != NULL) {
                rootdev = save_rootdev;
                if (!vfs_mountroot_try(""))
                        return;
        }

        /* 
         * Try values that may have been computed by the machine-dependant
         * legacy code.
         */
        if (rootdevnames[0] && !vfs_mountroot_try(rootdevnames[0]))
                return;
        if (rootdevnames[1] && !vfs_mountroot_try(rootdevnames[1]))
                return;

        /*
         * If we have a compiled-in default, and haven't already tried it, try
         * it now.
         */
#ifdef ROOTDEVNAME
        if (!(boothowto & RB_DFLTROOT))
                if (!vfs_mountroot_try(ROOTDEVNAME))
                        return;
#endif

        /* 
         * Everything so far has failed, prompt on the console if we haven't
         * already tried that.
         */
        if (!(boothowto & (RB_DFLTROOT | RB_ASKNAME)) && !vfs_mountroot_ask())
                return;
        panic("Root mount failed, startup aborted.");
}


int
vfs_mountroot_devfs(void)
{
        struct vnode *vp;
        struct nchandle nch;
        struct nlookupdata nd;
        struct mount *mp;
        struct vfsconf *vfsp;
        int error;
        struct ucred *cred = proc0.p_ucred;
        const char *devfs_path, *init_chroot;
        char *dev_malloced = NULL;

        if ((init_chroot = kgetenv("init_chroot")) != NULL) {
                size_t l;

                l = strlen(init_chroot) + sizeof("/dev");
                dev_malloced = kmalloc(l, M_MOUNT, M_WAITOK);
                ksnprintf(dev_malloced, l, "%s/dev", init_chroot);
                devfs_path = dev_malloced;
        } else {
                devfs_path = "/dev";
        }
        /*
         * Lookup the requested path and extract the nch and vnode.
         */
        error = nlookup_init_raw(&nd, devfs_path, UIO_SYSSPACE,
                                 NLC_FOLLOW, cred, &rootnch);

        if (error == 0) {
                devfs_debug(DEVFS_DEBUG_DEBUG,
                            "vfs_mountroot_devfs: nlookup_init is ok...\n");
                if ((error = nlookup(&nd)) == 0) {
                        devfs_debug(DEVFS_DEBUG_DEBUG,
                                    "vfs_mountroot_devfs: nlookup is ok...\n");
                        if (nd.nl_nch.ncp->nc_vp == NULL) {
                                devfs_debug(DEVFS_DEBUG_SHOW,
                                            "vfs_mountroot_devfs: nlookup: "
                                            "simply not found\n");
                                error = ENOENT;
                        }
                }
        }
        if (dev_malloced != NULL)
                kfree(dev_malloced, M_MOUNT), dev_malloced = NULL;
        devfs_path = NULL;
        if (error) {
                nlookup_done(&nd);
                devfs_debug(DEVFS_DEBUG_SHOW,
                            "vfs_mountroot_devfs: nlookup failed, error: %d\n",
                            error);
                return (error);
        }

        /*
         * Extract the locked+refd ncp and cleanup the nd structure
         */
        nch = nd.nl_nch;
        cache_zero(&nd.nl_nch);
        nlookup_done(&nd);

        /*
         * now we have the locked ref'd nch and unreferenced vnode.
         */
        vp = nch.ncp->nc_vp;
        if ((error = vget(vp, LK_EXCLUSIVE)) != 0) {
                cache_put(&nch);
                devfs_debug(DEVFS_DEBUG_SHOW,
                            "vfs_mountroot_devfs: vget failed\n");
                return (error);
        }
        cache_unlock(&nch);

        if ((error = vinvalbuf(vp, V_SAVE, 0, 0)) != 0) {
                cache_drop(&nch);
                vput(vp);
                devfs_debug(DEVFS_DEBUG_SHOW,
                            "vfs_mountroot_devfs: vinvalbuf failed\n");
                return (error);
        }
        if (vp->v_type != VDIR) {
                cache_drop(&nch);
                vput(vp);
                devfs_debug(DEVFS_DEBUG_SHOW,
                            "vfs_mountroot_devfs: vp is not VDIR\n");
                return (ENOTDIR);
        }

        vfsp = vfsconf_find_by_name("devfs");

        /*
         * Allocate and initialize the filesystem.
         */
        mp = kmalloc(sizeof(struct mount), M_MOUNT, M_ZERO|M_WAITOK);
        mount_init(mp, vfsp->vfc_vfsops);
        vfs_busy(mp, LK_NOWAIT);
        mp->mnt_vfc = vfsp;
        mp->mnt_pbuf_count = nswbuf_kva / NSWBUF_SPLIT;
        vfsp->vfc_refcount++;
        mp->mnt_stat.f_type = vfsp->vfc_typenum;
        mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
        if (vfsp->vfc_flags & VFCF_MPSAFE)
                mp->mnt_kern_flag |= MNTK_ALL_MPSAFE;
        strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
        mp->mnt_stat.f_owner = cred->cr_uid;
        mp->mnt_ncmounton = nch;
        vn_unlock(vp);

        /*
         * Mount the filesystem.
         */
        error = VFS_MOUNT(mp, "/dev", NULL, cred);
        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);

        /*
         * Put the new filesystem on the mount list after root.  The mount
         * point gets its own mnt_ncmountpt (unless the VFS already set one
         * up) which represents the root of the mount.  The lookup code
         * detects the mount point going forward and checks the root of
         * the mount going backwards.
         *
         * It is not necessary to invalidate or purge the vnode underneath
         * because elements under the mount will be given their own glue
         * namecache record.
         */
        if (!error) {
                if (mp->mnt_ncmountpt.ncp == NULL) {
                        /*
                         * allocate, then unlock, but leave the ref intact
                         */
                        cache_allocroot(&mp->mnt_ncmountpt, mp, NULL);
                        cache_unlock(&mp->mnt_ncmountpt);
                }
                vn_unlock(vp);
                cache_lock(&nch);
                nch.ncp->nc_flag |= NCF_ISMOUNTPT;
                cache_unlock(&nch);
                vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);

                /*
                 * XXX get the root of the fs and
                 * cache_setvp(mnt_ncmountpt...)
                 */
                mountlist_insert(mp, MNTINS_LAST);
                vn_unlock(vp);
                //checkdirs(&mp->mnt_ncmounton, &mp->mnt_ncmountpt);
                error = vfs_allocate_syncvnode(mp);
                if (error) {
                        devfs_debug(DEVFS_DEBUG_SHOW,
                                    "vfs_mountroot_devfs: "
                                    "vfs_allocate_syncvnode failed\n");
                }
                vfs_unbusy(mp);
                error = VFS_START(mp, 0);
                vrele(vp);
        } else {
                bzero(&mp->mnt_ncmounton, sizeof(mp->mnt_ncmounton));
                vn_syncer_thr_stop(mp);
                vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_coherency_ops);
                vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_journal_ops);
                vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_norm_ops);
                vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_spec_ops);
                vfs_rm_vnodeops(mp, NULL, &mp->mnt_vn_fifo_ops);
                mp->mnt_vfc->vfc_refcount--;
                vfs_unbusy(mp);
                kfree(mp, M_MOUNT);
                cache_drop(&nch);
                vput(vp);
                devfs_debug(DEVFS_DEBUG_SHOW,
                            "vfs_mountroot_devfs: mount failed\n");
        }

        devfs_debug(DEVFS_DEBUG_DEBUG,
                    "rootmount_devfs done with error: %d\n", error);
        return (error);
}


/*
 * Mount (mountfrom) as the root filesystem.
 */
static int
vfs_mountroot_try(const char *mountfrom)
{
        struct mount    *mp;
        char            *vfsname, *devname;
        int             error;
        char            patt[32];
        const char      *cp, *ep;
        char            *mf;
        struct proc     *p;
        struct vnode    *vp;

        vfsname = NULL;
        devname = NULL;
        mp      = NULL;
        error   = EINVAL;

        if (mountfrom == NULL)
                return(error);          /* don't complain */

        crit_enter();
        kprintf("Mounting root from %s\n", mountfrom);
        crit_exit();

        cp = mountfrom;
        /* parse vfs name and devname */
        vfsname = kmalloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
        devname = kmalloc(MNAMELEN, M_MOUNT, M_WAITOK);
        mf = kmalloc(MFSNAMELEN+MNAMELEN, M_MOUNT, M_WAITOK);
        for(;;) {
                for (ep = cp; (*ep != 0) && (*ep != ';'); ep++);
                bzero(vfsname, MFSNAMELEN);
                bzero(devname, MNAMELEN);
                bzero(mf, MFSNAMELEN+MNAMELEN);
                strncpy(mf, cp, MFSNAMELEN+MNAMELEN);

                vfsname[0] = devname[0] = 0;
                ksprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
                if (ksscanf(mf, patt, vfsname, devname) < 1)
                        goto end;

                /* allocate a root mount */
                error = vfs_rootmountalloc(vfsname,
                                devname[0] != 0 ? devname : ROOTNAME, &mp);
                if (error != 0) {
                        kprintf("Can't allocate root mount for filesystem '%s': %d\n",
                               vfsname, error);
                        goto end;
                }
                mp->mnt_flag |= MNT_ROOTFS;

                /* do our best to set rootdev (really just for UFS) */
                if (strcmp(vfsname, "hammer") != 0 &&
                    strcmp(vfsname, "hammer2") != 0 &&
                    (devname[0] != 0) && setrootbyname(devname)) {
                        kprintf("setrootbyname failed\n");
                }

                /* If the root device is a type "memory disk", mount RW */
                if (rootdev != NULL && dev_is_good(rootdev) &&
                    (dev_dflags(rootdev) & D_MEMDISK)) {
                        mp->mnt_flag &= ~MNT_RDONLY;
                }

                error = VFS_MOUNT(mp, NULL, NULL, proc0.p_ucred);

                if (!error)
                        break;
end:
                if(*ep == 0)
                        break;
                cp = ep + 1;
        }

        if (vfsname != NULL)
                kfree(vfsname, M_MOUNT);
        if (devname != NULL)
                kfree(devname, M_MOUNT);
        if (mf != NULL)
                kfree(mf, M_MOUNT);
        if (error == 0) {
                /* register with list of mounted filesystems */
                mountlist_insert(mp, MNTINS_FIRST);

                /* sanity check system clock against root fs timestamp */
                inittodr(mp->mnt_time);

                /* Get the vnode for '/'.  Set p->p_fd->fd_cdir to reference it. */
                mp = mountlist_boot_getfirst();
                if (VFS_ROOT(mp, &vp))
                        panic("cannot find root vnode");
                if (mp->mnt_ncmountpt.ncp == NULL) {
                        cache_allocroot(&mp->mnt_ncmountpt, mp, vp);
                        cache_unlock(&mp->mnt_ncmountpt);       /* leave ref intact */
                }
                p = curproc;
                p->p_fd->fd_cdir = vp;
                vref(p->p_fd->fd_cdir);
                p->p_fd->fd_rdir = vp;
                vref(p->p_fd->fd_rdir);
                vfs_cache_setroot(vp, cache_hold(&mp->mnt_ncmountpt));
                vn_unlock(vp);                  /* leave ref intact */
                cache_copy(&mp->mnt_ncmountpt, &p->p_fd->fd_ncdir);
                cache_copy(&mp->mnt_ncmountpt, &p->p_fd->fd_nrdir);

                vfs_unbusy(mp);
                if (mp->mnt_syncer == NULL) {
                        error = vfs_allocate_syncvnode(mp);
                        if (error)
                                kprintf("Warning: no syncer vp for root!\n");
                        error = 0;
                }
                VFS_START( mp, 0 );
        } else {
                if (mp != NULL) {
                        vn_syncer_thr_stop(mp);
                        vfs_unbusy(mp);
                        kfree(mp, M_MOUNT);
                }
                kprintf("Root mount failed: %d\n", error);
        }
        return(error);
}


static void
vfs_mountroot_ask_callback(char *name, cdev_t dev, bool is_alias,
    void *arg __unused)
{
        if (!is_alias && dev_is_good(dev) && (dev_dflags(dev) & D_DISK))
                kprintf(" \"%s\" ", name);
}


/*
 * Spin prompting on the console for a suitable root filesystem
 */
static int
vfs_mountroot_ask(void)
{
        char name[128];
        int llimit = 100;

        kprintf("\nManual root filesystem specification:\n");
        kprintf("  <fstype>:<device>  Specify root (e.g. ufs:da0s1a)\n");
        kprintf("  ?                  List valid disk boot devices\n");
        kprintf("  panic              Just panic\n");
        kprintf("  abort              Abort manual input\n");
        while (llimit--) {
                kprintf("\nmountroot> ");

                if (get_line(name, 128) < 0)
                        break;
                if (name[0] == 0) {
                        ;
                } else if (name[0] == '?') {
                        kprintf("Possibly valid devices for root FS:\n");
                        //enumerate all disk devices
                        devfs_scan_callback(vfs_mountroot_ask_callback, NULL);
                        kprintf("\n");
                        continue;
                } else if (strcmp(name, "panic") == 0) {
                        panic("panic from console");
                } else if (strcmp(name, "abort") == 0) {
                        break;
                } else if (vfs_mountroot_try(name) == 0) {
                        return(0);
                }
        }
        return(1);
}


static int
get_line(char *cp, int limit)
{
        char *lp;
        int dummy;
        int c;

        lp = cp;
        cnpoll(TRUE);
        for (;;) {
                c = cncheckc();

                switch (c) {
                case NOKEY:
                        tsleep(&dummy, 0, "cnpoll", hz / 25);
                        break;
                case -1:
                        goto done;
                case '\n':
                case '\r':
                        kprintf("\n");
                        *lp++ = '\0';
                        c = 0;
                        goto done;
                case '\b':
                case '\177':
                        if (lp > cp) {
                                kprintf("\b \b");
                                lp--;
                        } else {
                                kprintf("%c", 7);
                        }
                        continue;
                case '#':
                        kprintf("#");
                        lp--;
                        if (lp < cp)
                                lp = cp;
                        continue;
                case 'u' & 037:
                        /* NOTE: '@' no longer processed here, used for H2 */
                        lp = cp;
                        kprintf("%c", '\n');
                        continue;
                default:
                        if (lp - cp >= limit - 1) {
                                kprintf("%c", 7);
                        } else {
                                kprintf("%c", c);
                                *lp++ = c;
                        }
                        continue;
                }
        }
done:
        cnpoll(FALSE);
        return c;
}

/*
 * Convert a given name to the cdev_t of the disk-like device
 * it refers to.
 */
cdev_t
kgetdiskbyname(const char *name) 
{
        cdev_t rdev;

        /*
         * Get the base name of the device
         */
        if (strncmp(name, __SYS_PATH_DEV, sizeof(__SYS_PATH_DEV) - 1) == 0)
                name += sizeof(__SYS_PATH_DEV) - 1;

        /*
         * Locate the device
         */
        rdev = devfs_find_device_by_name("%s", name);
        if (rdev == NULL) {
                kprintf("no disk named '%s'\n", name);
        }
        /*
         * FOUND DEVICE
         */
        return(rdev);
}

/*
 * Set rootdev to match (name), given that we expect it to
 * refer to a disk-like device.
 */
static int
setrootbyname(char *name)
{
        cdev_t diskdev;

        diskdev = kgetdiskbyname(name);
        if (diskdev != NULL) {
                rootdev = diskdev;
                return (0);
        }
        /* set to NULL if kgetdiskbyname() fails so that if the first rootdev is
         * found by fails to mount and the second one isn't found, mountroot_try
         * doesn't try again with the first one
         */
        rootdev = NULL;
        return (1);
}

#ifdef DDB
DB_SHOW_COMMAND(disk, db_getdiskbyname)
{
        cdev_t dev;

        if (modif[0] == '\0') {
                db_error("usage: show disk/devicename");
                return;
        }
        dev = kgetdiskbyname(modif);
        if (dev != NULL)
                db_printf("cdev_t = %p\n", dev);
        else
                db_printf("No disk device matched.\n");
}
#endif

static int
vfs_sysctl_real_root(SYSCTL_HANDLER_ARGS)
{
        char *real_root;
        size_t len;
        int error;

        real_root = kgetenv("vfs.root.realroot");

        if (real_root == NULL)
                real_root = "";

        len = strlen(real_root) + 1;

        error = sysctl_handle_string(oidp, real_root, len, req);

        return error;
}

SYSCTL_PROC(_vfs, OID_AUTO, real_root,
            CTLTYPE_STRING | CTLFLAG_RD, 0, 0, vfs_sysctl_real_root,
            "A", "Real root mount string");