# finds the major:minor of the block device backing the root filesystem.
find_block_device() {
- local rootdev blkdev fs type opts misc
- while read blkdev fs type opts misc; do
- [[ $blkdev = rootfs ]] && continue # skip rootfs entry
- [[ $fs = $1 ]] && { rootdev=$blkdev; break; } # we have a winner!
- done < /proc/mounts
- [[ -b $rootdev ]] || return 1 # oops, not a block device.
- # get major/minor for the device
- ls -nLl "$rootdev" | \
- (read x x x x maj min x; maj=${maj//,/}; echo $maj:$min)
+ local majmin rootdev blkdev fs type opts misc
+ while read a b majmin c mpt opts d fs type opts misc; do
+ [[ $mpt = $1 ]] && { echo $majmin; break; } # we have a winner!
+ done < /proc/self/mountinfo
}
find_root_block_device() { find_block_device /; }