The OCEXEC flag used to be maintained per channel,
making it shared between all the file desciptors.
This has a unexpected side effects with regard to
channel passing drivers such as devdup (/fd),
devsrv (/srv) and devshr (/shr).
For example, opening a /srv file with OCEXEC
makes it impossible to be remounted by exportfs
as it internally does a exec() to mount and
re-export it. There is no way to reset the flag.
This change makes the OCEXEC flag per file descriptor,
so a open with the OCEXEC flag only affects the fd
group of the calling process, and not the channel
itself.
On rfork(RFFDG), the per file descriptor flags get
copied.
On dup(), the per file descriptor flags are reset.
The second modification is that /fd, /srv and /shr
should reject the ORCLOSE flag, as the files that
are returned have already been opend.
we already export mntauth() and mntversion(), so why not stop
being sneaky and just export mntattach() so bindmount() and
devshr can just call it directly with proper arguments being
checked.
we can also avoid handling #M attach specially in namec()
by having the devmnt's attach function do error(Enoattach).
as the Fgrp can be shared with other processes, we have to
recheck the fd index after locking the Fgrp in fdclose()
to make sure not to read beyond the bounds of the fd array.
this change is in preparation for amd64. the systab calling
convention was also changed to return uintptr (as segattach
returns a pointer) and the arguments are now passed as
va_list which handles amd64 arguments properly (all arguments
are passed in 64bit quantities on the stack, tho the upper
part will not be initialized when the element is smaller
than 8 bytes).
this is partial. xalloc needs to be converted in the future.
cinap_lenrek
cinap_lenrek
cinap_lenrek
Taru Karttunen