Files
Ciro Santilli 8d20f8ce30 llseek
2017-05-13 14:07:39 +01:00

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#!/bin/sh
set -x
insmod /fops.ko
mkdir -p /fops
mount -t debugfs none /fops
cd /fops/kernel_module_cheat
## Basic read.
cat fops
# => abcd
# dmesg => open
# dmesg => read
# dmesg => len = [0-9]+
# dmesg => close
## Basic write
printf '01' >fops
# dmesg => open
# dmesg => write
# dmesg => len = 1
# dmesg => buf = a
# dmesg => close
cat fops
# => 01cd
# dmesg => open
# dmesg => read
# dmesg => len = [0-9]+
# dmesg => close
## ENOSPC
printf '1234' >fops
printf '12345' >fops
echo "$?"
# => 8
cat fops
# => 1234
## seek
printf '1234' >fops
printf 'z' | dd bs=1 of=fops seek=2
cat fops
# => 12z4