fs/simpleramfs/mounts-root

#!/bin/sh
#
# You can run this script in case you boot with rdinit=/bin/sh and want to
# quickly mount the basic kernel filesystems.  It mounts them, but doesn't
# switch_root.
#

. /helpers.sh

# Finds the *last* /dev/mtd* device with the given realname
find_mtd()
{
  local result=
  while IFS=" :" read dev size erasesize name; do
    name=${name#\"}
    name=${name%\"}
    if [ "$name" = "$1" ]; then
      result=${dev#mtd}
      # fall through in case there's a subsequent device with same name
    fi
  done </proc/mtd
  [ -n "$result" ] && echo "$result"
}

find_mmc()
{
  local result=
  sgdisk -p /dev/mmcblk0 >/tmp/mmcpart 2>/dev/null
  while read number start end size unit code name; do
    if [ "$name" = "$1" ]; then
      result=$number
    fi
  done </tmp/mmcpart
  rm -f /tmp/mmcpart
  [ -n "$result" ] && echo "$result"
}

read_cmdline

# NOTE on ubi.mtd= vs. root=
#
# Previously, we relied on the installer+bootloader to set ubi.mtd=xxx, and
# then root=mtdblock:rootfs.  The problem with that is it depends on the
# installer/bootloader understanding about UBI devices, which means the
# installer for a *previous* version needs to understand the format of kernel
# parameters for the *next* (newly-installed) version.  That can make future
# upgrades more complicated.
#
# So what we do now is provide root=xxx, where xxx is the name of the mtd
# partition where the rootfs is installed (either rootfs0 or rootfs1).  It's
# the responsibility of the installed image, ie. this script, to know whether
# the stuff in rootfs0/rootfs1 is UBI or not.
#
# However, for backward compatibility, we still need to support kernel options
# of the form
#    ubi.mtd=rootfs0 root=mtdblock:rootfs
# which we treat as the new-style
#    root=rootfs0

# ubi.mtd= only overrides root= if root= is old-style.
if [ -n "$UBI_MTD" ]; then
  if [ -z "$ROOTDEV" -o "${ROOTDEV%%:*}" = "mtdblock" ]; then
    ROOTDEV=$UBI_MTD
  fi
fi


replacefirst() {
  local left right
  # same as sed -e 's/$2/$3/' $1
  right=${1#*$2}
  left=${1%%$2*}
  echo "$left$3$right"
}


# Returns true if the string $1 starts with the string $2.
startswith() {
  [ "${1#$2}" != "$1" ]
}


# host:path format in root= means we should do an NFS root
if [ "${ROOTDEV#*:/}" != "$ROOTDEV" ]; then
  NFSROOT=$ROOTDEV
fi

if [ -n "$NFSROOT" ]; then
  log "Mounting nfs: '$NFSROOT'"
  if [ -n "$IP" ]; then
    # Can't necessarily count on the kernel to do this, in case our
    # ethernet driver is a kernel module instead of built-in.
    log "  IP initialization: '$IP'"
    echo "$IP" | {
      IFS=: read client_ip server_ip gw_ip netmask hostname device \
              autoconf dns0_ip dns1_ip junk
      [ -z "$device" ] && device=eth0
      if [ "$ip" != "auto" ]; then
        ifconfig "$device" "$client_ip"
      fi
    }
  fi
  NFSADDR=${NFSROOT%:*}
  NFSOPTS="nolock,proto=tcp,mountproto=tcp,vers=3,mountvers=3,addr=$NFSADDR"
  # 7429 internal PHY takes >1 second to get link.
  # If the NFS mount fails, wait a while and try again.
  for s in 2 2 2 0; do \
    mount -o $NFSOPTS -t nfs "$NFSROOT" /rootfs && break
    log "NFS mount failed, sleeping"
    sleep $s
    false
  done || die "NFS mount failed"
  log "Mounted nfsroot='$NFSROOT'"
elif [ -n "$ROOTDEV" ]; then
  if startswith "$ROOTDEV" /dev; then
    mount -o ro -t squashfs "$ROOTDEV" /rootfs ||
        die "root='$ROOTDEV' mount failed"
    log "Mounted root='$ROOTDEV'"
  elif startswith "$ROOTDEV" 9p:; then
    fsdev="${ROOTDEV#9p:}"
    mount -t 9p -o trans=virtio,version=9p2000.L "$fsdev" /rootfs ||
        die "root='$fsdev' (9p) mount failed"
    log "Mounted root='$fsdev' (9p)"
  else
    for s in 1 1 0; do
      KERNELNAME=$(replacefirst $ROOTDEV rootfs kernel)
      mtd=/dev/mtd$(find_mtd "$ROOTDEV")
      mmcraw=/dev/mmcblk0p$(find_mmc "$ROOTDEV")
      IMAGENAME=$(replacefirst $ROOTDEV rootfs image)
      mmcvfat=/dev/mmcblk0p$(find_mmc "$IMAGENAME")
      [ -e "$mtd" -o -e "$mmcraw" -o -e "$mmcvfat" -o -e $ROOTDEV ] && break
      log "No rootfs found, sleeping"
      # eMMC is sometimes slow to appear; try again.
      sleep $s
      false
    done
    if [ -e "$mtd" ]; then
      log "Found root='$ROOTDEV': $mtd"
      # In this build, the rootdev mtd is always an UBI device.
      ubidetach -p "$mtd"  # Just in case kernel automounted it somewhere
      ubiattach -p "${mtd}ro"
      # In this build, the newly-found mtd is always named 'rootfs'
      ubi_mtd=$(find_mtd "rootfs")
      [ -n "$ubi_mtd" ] || (cat /proc/mtd; die "no mtd named 'rootfs'")
      ROOTDEV=/dev/mtdblock$ubi_mtd
      KERNELDEV=/dev/mtdblock$(find_mtd "$KERNELNAME")
    elif [ -e "$mmcraw" ]; then
      log "Found root='$ROOTDEV': $mmcraw"
      ROOTDEV=$mmcraw
      KERNELDEV=/dev/mmcblk0p$(find_mmc "$KERNELNAME")
    elif [ -e "$mmcvfat" ]; then
      log "Found root='$ROOTDEV': $mmcvfat"
      mount -t vfat -o ro,nodev,noexec,nosuid "$mmcvfat" /vfat
      KERNELDEV=/dev/loop0
      ROOTDEV=/dev/loop1
      losetup $KERNELDEV /vfat/vmlinuz.img
      losetup $ROOTDEV /vfat/rootfs.img
    else
      cat /proc/mtd
      log "root='$ROOTDEV' is not an mtd device."
    fi
    args=$(readverity $KERNELDEV)
    args=$(replacefirst "$args" ROOT_DEV "$ROOTDEV")
    args=$(replacefirst "$args" HASH_DEV "$KERNELDEV")
    if ! dmsetup create -r vroot --table "$args"; then
      veritynote=
      # TODO(apenwarr): fix uboot, then remove special case for armplatform.
      read x y armplatform platform junk </proc/cpuinfo
      if [ "$platform" = "BCM7425B0" \
          -o "$platform" = "BCM7429B0" \
          -o "$armplatform" = "ARMv7" ]; then
        log 'dmsetup failed: platform is unsigned device, continuing anyway.'
        SQUASHFS=$ROOTDEV
      else
        die "dmsetup failed"
      fi
    else
      SQUASHFS="/dev/mapper/vroot"
      veritynote="(verity)"
    fi

    mount -o ro -t squashfs "$SQUASHFS" /rootfs ||
        die "root='$ROOTDEV' mount failed $veritynote"
    log "Mounted root='$ROOTDEV' $veritynote"
  fi
else
  die "No root= or nfsroot= provided."
fi

mount -t tmpfs none /rootfs/tmp

#TODO(apenwarr): network setup code depends on this file, but it shouldn't.
# It should just always refuse to touch the network if the network was already
# set up.
[ -n "$NFSROOT" ] && echo NFS >/rootfs/tmp/NFS

[ -n "$DEBUG" ] && echo DEBUG >/rootfs/tmp/DEBUG

exit 0