On 14 September 2012 06:01, Roland Mainz <roland.ma...@nrubsig.org> wrote: > Hi! > > ---- > > Attached (as "astksh_chroot_cd_devfd_cd_f_20120911_001.diff.txt") is a > patch which fixes two issues with "cd": > 1. $ cd /dev/fd/$fd # doesn't work in chroot'ed environments when > /dev/fd is not mounted (thanks to CERN staff for reporting this). > 2. POSIX does not mandate _any_ paths. Since doing a "cd" relative to > a directory fd has become very popular the request was made to add an > alternative to using /dev/fd which is more or less acceptable for the > POSIX people. Based on that and a few discussions I added the option > -f to cd that a directory descriptor can be passed and the path given > is relative to that file descriptor. > > Notes: > - The code introduces a new function called |pathdevfd2relpathfd()| in > libast which can extract the fd number from a /dev/fd/$fd path (even > nested) > - If files or directories are opened relative to /dev/fd/$fd/$path > |sfopen()|/|sfopenat()| will now bypass the /dev/fd filesystem > completely (which gives a nice performance boost). The only exception > is that this can *NOT* be done for a plain /dev/fd/$fd, e.g. > /dev/fd/15. The problem is that there is AFAIK no way to open a file > from a file descriptor without using the /dev/fd filesystem or using > |dup()| ... but |dup()| rules itself out because the resulting > "cloned" fd still shares attributes like the current seek position > with the original fd...
Patch looks good to me. Testing is in progress, from an initial glance it seems to work in chroot. Lionel _______________________________________________ ast-developers mailing list ast-developers@research.att.com https://mailman.research.att.com/mailman/listinfo/ast-developers
