Since this is called in fork() it does rather need to give the child
process the parent's emulation root.
This means that (for example) an emulated shell will, by default, run
programs from the emulation root.
avoid having to allocate space in the 'stackgap'
- which is very LWP unfriendly.
The additional code for non-emulation namei() is trivial, the reduction for
the emulations is massive.
The vnode for a processes emulation root is saved in the cwdi structure
during process exec.
If the emulation root the TRYEMULROOT flag are set, namei() will do an initial
search for absolute pathnames in the emulation root, if that fails it will
retry from the normal root.
".." at the emulation root will always go to the real root, even in the middle
of paths and when expanding symlinks.
Absolute symlinks found using absolute paths in the emulation root will be
relative to the emulation root (so /usr/lib/xxx.so -> /lib/xxx.so links
inside the emulation root don't need changing).
If the root of the emulation would be returned (for an emulation lookup), then
the real root is returned instead (matching the behaviour of emul_lookup,
but being a cheap comparison here) so that programs that scan "../.."
looking for the root dircetory don't loop forever.
The target for symbolic links is no longer mangled (it used to get the
CHECK_ALT_xxx() treatment, so could get /emul/xxx prepended).
CHECK_ALT_xxx() are no more. Most of the change is deleting them, and adding
TRYEMULROOT to the flags to NDINIT().
A lot of the emulation system call stubs could now be deleted.
separate functions that don't do the copyout.
This allows all the compat_xxx versions to convert the 'struct stat' to
the correct format without using the 'stackgap'.
The stackgap isn't at all LWP friendly, and needs to be removed from
any compat functions that might involve threads (inc. clone()).
The code is still binary compatible with existing LKMs.
P_*/L_* naming convention, and rename the in-kernel flags to avoid
conflict. (P_ -> PK_, L_ -> LW_ ). Add back the (now unused) LSDEAD
constant.
Restores source compatibility with pre-newlock2 tools like ps or top.
Reviewed by Andrew Doran.
(fdp->fd_lastfile - i) against fd_knlistsize. Otherwise we can
call knote_fdclose() on a file descriptor that doesn't have a knote.
This issue explains random panics I have had on process exit over the
past few years.
compare fd and fdp->fd_lastfile in fdrelease(), so change the test to a
more explicit one. Spotted by Matt Thomas.
Should fix the panic reported by Matthias Scheler.
Hence, make find_last_set return -1 in such situation, and initialize it
such. Otherwise, with 0 meaning two things, it confused the F_CLOSEM
fcntl which could end up looping indifintely (PR#28929 by Brian Marcotte).
However, this change enlightens another bug in fdcopy(), where more entries
than needed were cleared in the new file descriptor table, so the memset()
call there is fixed too.
Analyzed with the help of Greg Oster.
1. make fileops const
2. add 2 new negative errno's to `officially' support the cloning hack:
- EDUPFD (used to overload ENODEV)
- EMOVEFD (used to overload ENXIO)
3. Created an fdclone() function to encapsulate the operations needed for
EMOVEFD, and made all cloners use it.
4. Centralize the local noop/badop fileops functions to:
fnullop_fcntl, fnullop_poll, fnullop_kqfilter, fbadop_stat
Fix a potential race condition when reallocating storage for file descriptors
(even for non-SMP kernels).
Add missing locks for `struct file' ref count updates.
to pool_init. Untouched pools are ones that either in arch-specific
code, or aren't initialiased during initial system startup.
Convert struct session, ucred and lockf to pools.
specifically, don't keep a stale pointer in fd_ofiles.
it isn't needed anymore as fd allocation is now done using bitmaps.
- clean up dupfdopen() a little.
- don't call fd_used() unnecessarily.
* introduce fsetown(), fgetown(), fownsignal() - this sets/retrieves/signals
the owner of descriptor, according to appropriate sematics
of TIOCSPGRP/FIOSETOWN/SIOCSPGRP/TIOCGPGRP/FIOGETOWN/SIOCGPGRP ioctl; use
these routines instead of custom code where appropriate
* make every place handling TIOCSPGRP/TIOCGPGRP handle also FIOSETOWN/FIOGETOWN
properly, and remove the translation of FIO[SG]OWN to TIOC[SG]PGRP
in sys_ioctl() & sys_fcntl()
* also remove the socket-specific hack in sys_ioctl()/sys_fcntl() and
pass the ioctls down to soo_ioctl() as any other ioctl
change discussed on tech-kern@
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