[[!meta copyright="Copyright © 2013, 2014 Free Software Foundation, Inc."]]

[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]

[[!tag open_issue_hurd]]

/!\ [[!tag open_issue_documentation]] Does this completely resolve
[[community/gsoc/project_ideas/server_overriding]]?


# IRC, freenode, #hurd, 2013-01-05

    <youpi> so we have a "remap" root translator?
    <youpi> I  mean this:
    <youpi> I'd run my shell in a subhurd whose only difference is that the
      root is not the system's root, but my own
    <youpi> which catches accesses to /servers/socket/2 for instance
    <youpi> but leaves the rest flow through the system's root
    <braunr> there is just boot, i don't think it can do that
    <youpi> it'd be useful to have that
    <youpi> it'd be a very useful feature
    <youpi> to use another tcp/ip stack etc.
    <braunr> what happens when translators need to locate other translators
      used by the client ?
    <youpi> can't it tell the client to ask the real system's root?
    <youpi> (with the same path)
    <youpi> I don't remember the exact reply name
    <braunr> hum, it's getting too fuzzy for my head :p
    <youpi> well, I mean it's just like translator entries in an ext2fs
    <youpi> ext2fs replies "not me, this one"
    <braunr> but what if e.g. a user has its own pflocal, and when calling
      another translator, that one wants to contact the pflocal used by the
      client ?
    <youpi> ah, that won't work of course
    <braunr> do we actually have such cases btw ?
    <braunr> procfs perhaps
    <youpi> I don't think we'd want it actually
    <braunr> but isn't that required sometimes ?
    <youpi> inside a shell script, yes
    <braunr> for example, a storeio translator could ask about the priority
      properties of the client to proc
    <youpi> but I don't remember a case where an external translator would need
      the access
    <youpi> well, that's actually what we want
    <youpi> we don't want to fool the storeio with user-provided data :)
    <braunr> yes
    <youpi> unless the user starts the storeio himself, in which case he will
      have to re-root it
    <braunr> so it has to locate the right translator, despite not using the
      remap root translator
    <youpi> err, it will already
    <youpi> by just using the system's path
    <braunr> ?
    <youpi> maybe you need to say exactly what "it" and "right" are :)
    <braunr> ok, let's imagine your previous example with a subhurd and pfinet
    <braunr> the remap translator would imply that users from the subhurd
      *directly* access all services from the main hurd, except when routed
      otherwise by the remap translator to pfinet
    <youpi> by "directly", I mean asking the remap translator, which gives as
      answer "not me, the root"
    <braunr> now, what if a translator in the main hurd wants e.g. network
      stats from pfinet, it will ask the main one, not the one obtained through
      remap
    <braunr> yes
    <youpi> that's completely fine
    <braunr> ah
    <braunr> that's fine if the results don't matter
    <youpi> to get network stats from the user pfinet you'd have to be inside
      the shell using the remap translator
    <braunr> otherwise they're inconsistent
    <braunr> yes
    <youpi> I don't see why you'd want to get the pfinet stats from outside
    <youpi> you mean ethernet board usage?
    <braunr> service interactions
    <braunr> i can't think of anything relevant with pfinet
    <braunr> but imagine pflocal and credentials
    <youpi> I believe that'd still be ok
    <youpi> i.e. things outside the remap want to know the actual system things
    <youpi> while things inside want to know the remapped things
    <youpi> and you need that to avoid getting fooled by the user remapping
    <braunr> for credentials, i think it works because the client provides
      rights, so it would provide rights to the remapped translators in this
      case
    <braunr> this would need to be generalized
    <youpi> I believe it's already general
    <braunr> well no
    <braunr> procfs for example will always talk to the "true" proc server
    <youpi> sure
    <youpi> that's what I want from the outside
    <youpi> if the user, from the inside, wants another view, he'll have to
      start another procfs
    <youpi> his own one
    <braunr> ok
    <youpi> attached to the remapping


## IRC, freenode, #hurd, 2013-01-29

    <youpi> ok, the remap translator was too easy
    <youpi> just took fakeroot.c
    <youpi> added if (!strcmp("bin/foo", filename))         filename =
      "bin/bash"; in 
    <youpi> netfs_S_dir_lookup
    <youpi> and it just works

[[hurd/interface/dir_lookup]].

    <youpi> ok, remap does indeed take my own pfinet
    <youpi> good :)
    <youpi> pfinet's tun seems to be working too
    <youpi> it's however not really flexible, it has to show up in /dev/tunx
    <youpi> I'll have a look at fixing that
    <youpi> yep, works fine


## IRC, freenode, #hurd, 2013-02-01

    <youpi> braunr: as I expected, simply passing FS_RETRY_REAUTH does the
      remapping trick


# IRC, freenode, #hurd, 2013-02-12

    <braunr>
      http://darnassus.sceen.net/~hurd-web/community/gsoc/project_ideas/server_overriding/
    <braunr> youpi: isn't that your remap translator ?
    <youpi> completely
    <youpi> remap being (5)


# IRC, freenode, #hurd, 2013-02-25

    <youpi> I'm just having an issue with getcwd getting in the sky
    <youpi> I wonder whether libc might need patching to understand it's in
      some sort of chroot
    <youpi> or perhaps remap fixed into avoiding .. of / being odd
    <youpi> erf, it's actually an explicit error
    <youpi> libc just doesn't want to have a ".." / being different from CRDIR
    <youpi> let me just comment out that :)
    <youpi> way better :)
    <youpi> yep, just works fine


# IRC, freenode, #hurd, 2013-03-16

    <braunr> youpi: is the /bin/remap --help output correct ?


# [[hurd/fsysopts]]

Doesn't support [[hurd/fsysopts]].