PR:		73778
Submitted by:	Andriy Gapon <avg@icyb.net.ua>
MFC after:	2 weeks

  structure in the struct pointed to by the 3rd argument for IPC_STAT and
  get rid of the 4th argument.  The old way returned a pointer into the
  kernel array that the calling function would then access afterwards
  without holding the appropriate locks and doing non-lock-safe things like
  copyout() with the data anyways.  This change removes that unsafeness and
  resulting race conditions as well as simplifying the interface.
- Implement kern_foo wrappers for stat(), lstat(), fstat(), statfs(),
  fstatfs(), and fhstatfs().  Use these wrappers to cut out a lot of
  code duplication for freebsd4 and netbsd compatability system calls.
- Add a new lookup function kern_alternate_path() that looks up a filename
  under an alternate prefix and determines which filename should be used.
  This is basically a more general version of linux_emul_convpath() that
  can be shared by all the ABIs thus allowing for further reduction of
  code duplication.

from the userland and pushes results back and the second which does
actual processing. Use the latter to eliminate stackgap in the linux wrapper
of that syscall.

MFC after:      2 weeks

Submitted by:	Jung-uk Kim <jkim@niksun.com>

Use positive, not negative logic.

on AMD64, and the general case where the emulated platform has different
size pointers than we use natively:
- declare certain structure members as l_uintptr_t and use the new PTRIN
  and PTROUT macros to convert to and from native pointers.
- declare some structures __packed on amd64 when the layout would differ
  from that used on i386.
- include <machine/../linux32/linux.h> instead of <machine/../linux/linux.h>
  if compiling with COMPAT_LINUX32. This will need to be revisited before
  32-bit and 64-bit Linux emulation support can coexist in the same kernel.
- other small scattered changes.

This should be a no-op on i386 and Alpha.

1.36      +73 -60    src/sys/compat/linux/linux_ipc.c
1.83      +102 -48   src/sys/kern/sysv_shm.c
1.8       +4 -0      src/sys/sys/syscallsubr.h

That change was intended to support vmware3, but
wantrem parameter is useless because vmware3 uses SYSV shared memory
to talk with X server and X server is native application.
The patch worked because check for wantrem was not valid
(wantrem and SHMSEG_REMOVED was never checked for SHMSEG_ALLOCATED segments).

Add kern.ipc.shm_allow_removed (integer, rw) sysctl (default 0) which when set
to 1 allows to return removed segments in
shm_find_segment_by_shmid() and shm_find_segment_by_shmidx().

MFC after:	1 week

argument to the functions shm{at,ctl}1 and shm_find_segment_by_shmid{x}.
The BSD semantics didn't allow the usage of shared segment after
being marked for removal through IPC_RMID.

The patch involves the following functions:
  - shmat
  - shmctl
  - shm_find_segment_by_shmid
  - shm_find_segment_by_shmidx
  - linux_shmat
  - linux_shmctl

Submitted by:	Orlando Bassotto <orlando.bassotto@ieo-research.it>
Reviewed by:	marcel

Change all in-tree consumers to include <sys/limits.h>

Discussed on:	standards@
Partially submitted by: Craig Rodrigues <rodrigc@attbi.com>