On Tue, May 25, 2021 at 11:43 AM Menglong Dong <menglong8.dong@xxxxxxxxx> wrote: > > On Tue, May 25, 2021 at 9:02 AM Josh Triplett <josh@xxxxxxxxxxxxxxxx> wrote: > > > ...... > > > > As far as I can tell, this will break if the user wants to use > > ".mybinary" or ".mydir/mybinary" as the name of their init program. > > > > For that matter, it would break "...prog" or "...somedir/prog", which > > would be strange but not something the kernel should prevent. > > > > Wow, seems I didn't give enough thought to it. > > > I don't think this code should be attempting to recreate > > relative-to-absolute filename resolution. > > Trust me, I don't want to do it either. However, I need to check if > ramdisk_execute_command exist before chroot while the cpio is unpacked > to '/root'. > > Maybe I can check it after chroot, but I need to chroot back if it not > exist. Can I chroot back in a nice way? > > I tried to move the mount on '/root' to '/' before I do this check in > absolute path, but seems '/' is special, the lookup of '/init' never > follow the mount on '/' and it can't be found. However, if I lookup > '/../init', it can be found! > I have figured it out. While path lookup, '/' won't follow the mount. However, with the set of LOOKUP_DOWN, it will be followed. So I will move the mount on '/root' to '/' and check the exist of ramdisk_execute_command with LOOKUP_DOWN setted. Seems there is still a long way to go on kernel...... Thanks! Menglong Dong
