Implement robust futexes. Most of the code is modelled after
what Linux does. This is because robust futexes are mostly
userspace thing which we cannot alter. Two syscalls maintain
pointer to userspa

Implement robust futexes. Most of the code is modelled after
what Linux does. This is because robust futexes are mostly
userspace thing which we cannot alter. Two syscalls maintain
pointer to userspace list and when process exits a routine
walks this list waking up processes sleeping on futexes
from that list.

Reviewed by: kib (mentor)
MFC after: 1 month

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MFP4: Turn emul_lock into a mutex.

Submitted by: rdivacky

MFP4: 115220, 115222

- Fix style(9) and reduce diff between amd64 and i386.
- Prefix Linuxulator macros with LINUX_ to prevent future collision.

Partial MFp4 of 114977:
Whitespace commit: Fix grammar, spelling and punctuation.

Submitted by: "Scot Hetzel" <swhetzel@gmail.com>

MFp4 (114193 (i386 part), 114194, 114195, 114200):
- Dont "return" in linux_clone() after we forked the new process in a case
of problems.
- Move the copyout of p2->p_pid outside the emul_lock c

MFp4 (114193 (i386 part), 114194, 114195, 114200):
- Dont "return" in linux_clone() after we forked the new process in a case
of problems.
- Move the copyout of p2->p_pid outside the emul_lock coverage in
linux_clone().
- Cache the em->pdeath_signal in a local variable and move the copyout
out of the emul_lock coverage.
- Move the free() out of the emul_shared_lock coverage in a preparation
to switch emul_lock to non-sleepable lock (mutex).

Submitted by: rdivacky

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MFp4 (part of 114132):
- Fix a LOR caused by holding emul_lock and proctree_lock at once.

Submitted by: rdivacky

Remove extern int hz; use proper include file instead.

No need to synchronize linux_schedtail with linux_proc_init.
p->p_emuldata is properly initialized in the time when the child can run.

Do not set p->p_emuldata to NULL when the process is exiting.
I

No need to synchronize linux_schedtail with linux_proc_init.
p->p_emuldata is properly initialized in the time when the child can run.

Do not set p->p_emuldata to NULL when the process is exiting.
It does not make any sense and only costs 2 mutex operations.

Do not lock emul_data to unlock it on the very next line.
Comment on possible race while there.

Reparent all procs that are part of a threading group but not its leaders
to init and SIGCHLD init to finish the zombies off. This fixes zombies
left after opera's exit. [1]

There is no need to lock p_em in the linux_proc_init CLONE_THREAD
case because the process cannot change the address of the p_em->shared
because its currently running this code path.
Move assigning of em->shared outside emul_shared_lock.

Noticed by: Scott Robbins <scottro@nyc.rr.com> [1]
Submitted by: rdivacky

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MFp4 (113077, 113083, 113103, 113124, 113097):

Dont expose em->shared to the outside world before its properly
initialized. Might not affect anything but its at least a better
coding style.

Don

MFp4 (113077, 113083, 113103, 113124, 113097):

Dont expose em->shared to the outside world before its properly
initialized. Might not affect anything but its at least a better
coding style.

Dont expose em via p->p_emuldata until its properly initialized.
This also enables us to get rid of some locking and simplify the
code because we are workin on a local copy.

In linux_fork and linux_vfork create the process in stopped state
to be sure that the new process runs with fully initialized emuldata
structure [1]. Also fix the vfork (both in linux_clone and linux_vfork)
race that could result in never woken up process [2].

Reported by: Scot Hetzel [1]
Suggested by: jhb [2]
Reviewed by: jhb (at least some important parts)
Submitted by: rdivacky
Tested by: Scot Hetzel (on amd64)

Change 2 comments (in the new code) to comply to style(9).

Suggested by: jhb

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MFp4 (112499):
Protect em->shared with the lock in case of CLONE_THREAD.

Submitted by: rdivacky

MFp4 (112498):
Rename the locking flags to EMUL_DOLOCK and EMUL_DONTLOCK to prevent confusion.

Submitted by: rdivacky

MFp4:
- semi-automatic style fixes

Group pid and parent are shared in a case of CLONE_THREAD not CLONE_VM.
This fix lets clone02 LTP test pass with 2.6 emulation. In reality 99%
of the cases are that CLONE_VM and CLONE_THREAD are both

Group pid and parent are shared in a case of CLONE_THREAD not CLONE_VM.
This fix lets clone02 LTP test pass with 2.6 emulation. In reality 99%
of the cases are that CLONE_VM and CLONE_THREAD are both set so it
seemed to work.

Submitted by: rdivacky

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MFP4:
Implement prctl().

Submitted by: rdivacky
Tested with: LTP

- change if (cond) panic() to KASSERT.
- Dont forget to free em in a case of error.

Suggested by: ssouhlal
Submitted by: rdivacky
Tested with: LTP

- Extend the coverage of PROC_LOCK to cover wakeup(&p->p_emuldata);
- Lock the emuldata in a case when we just created it.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Suggested by: jhb

FREE -> free

Submitted by: rdivacky

MALLOC -> malloc and FREE -> free

Submitted by: rdivacky
Pointed out by: jhb

Fix the DEBUG build:
- linux_emul.c [1]
- linux_futex.c [2]

Sponsored by: Google SoC 2006 [1]
Submitted by: rdivacky [1]
netchild [2]

Style fixes to comments.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Noticed by: jhb, ssouhlal

Add some new files needed for linux 2.6.x compatibility.

Please don't style(9) the NetBSD code, we want to stay in sync. Not imported
on a vendor branch since we need local changes.

Sponsored by: G

Add some new files needed for linux 2.6.x compatibility.

Please don't style(9) the NetBSD code, we want to stay in sync. Not imported
on a vendor branch since we need local changes.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
With help from: manu@NetBSD.org
Obtained from: NetBSD (linux_{futex,time}.*)

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