Implement all futex atomic operations in assembler to not depend on the
fuword() that does not allow to distinguish between -1 and failure return.
Correctly return 0 from atomic operations on success.
In collaboration with: rdivacky
Tested by: Scot Hetzel <swhetzel gmail com>, Milos Vyletel <mvyletel mzm cz>
Sponsored by: Google SoC 2007
vmcnts. This can be used to abstract away pcpu details but also changes
to use atomics for all counters now. This means sched lock is no longer
responsible for protecting counts in the switch routines.
Contributed by: Attilio Rao <attilio@FreeBSD.org>
sendmsg() while using a 0-length msg_controllen. This isn't allowed in
the FreeBSD system call ABI, so detect this case and set msg_control to
NULL. This allows Linux ping to work.
Submitted by: rdivacky
Linux SCSI SG passthrough device API. The intention is to allow for both
running of Linux apps that want to talk to /dev/sg* nodes, and to facilitate
porting of apps from Linux to FreeBSD. As such, both native and linuxolator
entry points and definitions are provided.
Caveats:
- This does not support the procfs and sysfs nodes that the Linux SG
driver provides. Some Linux apps may rely on these for operation,
others may only use them for informational purposes.
- More ioctls need to be implemented.
- Linux uses a naming scheme of "sg[a-z]" for devices, while FreeBSD uses a
scheme of "sg[0-9]". Devfs aliasis (symlinks) are automatically created
to link the two together. However, tools like camcontrol only see the
native names.
- Some operations were originally designed to return byte counts or other
data directly as the syscall return value. The linuxolator doesn't appear
to support this well, so this driver just punts for these cases.
Now that the driver is in place, others are welcome to add missing
functionality. Thanks to Roman Divacky for pushing this work along.
and flags with an sxlock. This leads to a significant and measurable
performance improvement as a result of access to shared locking for
frequent lookup operations, reduced general overhead, and reduced overhead
in the event of contention. All of these are imported for threaded
applications where simultaneous access to a shared file descriptor array
occurs frequently. Kris has reported 2x-4x transaction rate improvements
on 8-core MySQL benchmarks; smaller improvements can be expected for many
workloads as a result of reduced overhead.
- Generally eliminate the distinction between "fast" and regular
acquisisition of the filedesc lock; the plan is that they will now all
be fast. Change all locking instances to either shared or exclusive
locks.
- Correct a bug (pointed out by kib) in fdfree() where previously msleep()
was called without the mutex held; sx_sleep() is now always called with
the sxlock held exclusively.
- Universally hold the struct file lock over changes to struct file,
rather than the filedesc lock or no lock. Always update the f_ops
field last. A further memory barrier is required here in the future
(discussed with jhb).
- Improve locking and reference management in linux_at(), which fails to
properly acquire vnode references before using vnode pointers. Annotate
improper use of vn_fullpath(), which will be replaced at a future date.
In fcntl(), we conservatively acquire an exclusive lock, even though in
some cases a shared lock may be sufficient, which should be revisited.
The dropping of the filedesc lock in fdgrowtable() is no longer required
as the sxlock can be held over the sleep operation; we should consider
removing that (pointed out by attilio).
Tested by: kris
Discussed with: jhb, kris, attilio, jeff
semi-automatic style(9)
The futex stuff already differs a lot (only a small part does not differ)
from NetBSD, so we are already way off and can't apply changes from NetBSD
automatically. As we need to merge everything by hand already, we can even
make the files comply to our world order.
- 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
cannot change (because its referenced by curthread). This fixes
a LOR caused by acquiring emul_shared_lock while holding emul_lock.
Fix typo in comment.
Submitted by: rdivacky
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
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
to open() [1].
Improve locking for accessing session control structures [2].
Try to document (most likely harmless) races in the code [3].
Based on submission by: Intron (intron at intron ac) [1]
Reviewed by: jhb [2]
Discussed with: netchild, rwatson, jhb [3]
Now (ok it's been a while...) that FreeBSD has RLIMIT_AS too, we can use
it in the linuxolator instead of ignoring it.
This fixes a LTP test.
Submitted by: rdivacky
No need to lock prison in a case of linux_use26 because the int
setting is atomic and process cannot leave jail.
Submitted by: kib
Reviewed by: jhb
Requested by: rdivacky
Dont lock em in a case of just using em->shared->group_pid because
the group_pid never changes.
Submitted by: rdivacky
Reviewed by: kib
Glanced at by: jhb
Redo the checking for 2.6 emulation. We now cache the value of
use26 and replace calls to linux_get_osrelease() + parsing with
a call to linux_use26(). Typical path is lockless now.
Pointed out by: kib
This allows to ship RELENG_7_0 with a default osrelease of 2.4.2 and the
possibility to enable 2.6.x emulation without the possible performance
impact of the previous version of the check.
Submitted by: rdivacky
- Move linux_nanosleep() from src/sys/amd64/linux32/linux32_machdep.c to
src/sys/compat/linux/linux_time.c.
- Validate timespec ranges before use as Linux kernel does.
- Fix l_timespec structure.
- Clean up style(9) nits.
Add rudimentary IPC_INFO/MSG_INFO command support for linux_msgctl()
to pacify Linux ipcs(1). While I am here, add more bound checks
for linux_msgsnd() and linux_msgrcv().
Fixes for 'blocking in fifoor state' problem of LTP tests.
linux_*stat*() functions were opening files with O_RDONLY to get
major/minor pair for char/block special files. Unfortunately,
when these functions are used against fifo, it is blocked forever
because there is no writer. Instead, we only open char/block special
files for major/minor conversion. We have to get rid of kern_open()
entirely from translate_path_major_minor() but today is not the day.
While I am here, add checks for errors before calling
translate_path_major_minor().
- Currently LINUX_MAX_COMM_LEN is smaller than MAXCOMLEN, but in case
this will change we have a buffer overflow. Apply some defensive
programming to DTRT when this should happen.
- Use copyinstr() instead of copyin where appropriate.
* Fallback to copyin() in case of ENAMETOOLONG. [1]
* Use the right source and destination (it was wrong before).
- Use strlcpy instead of strcpy.
- Properly lock the read case (PR_GET_NAME) like the write case.
Reviewed by: rwatson (except [1])
Suggested by: rwatson [1]
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
__WCLONE. This fixes it thus fixing skype/teamspeak to not keep zombies
after exit.
Submitted by: rdivacky
Reported by: Bakul Shah (bakul at bitblocks com)
specific privilege names to a broad range of privileges. These may
require some future tweaking.
Sponsored by: nCircle Network Security, Inc.
Obtained from: TrustedBSD Project
Discussed on: arch@
Reviewed (at least in part) by: mlaier, jmg, pjd, bde, ceri,
Alex Lyashkov <umka at sevcity dot net>,
Skip Ford <skip dot ford at verizon dot net>,
Antoine Brodin <antoine dot brodin at laposte dot net>
