Commit Graph

171 Commits

Author SHA1 Message Date
Jeff Roberson
bf422e5f27 - Implement a lockless file descriptor lookup algorithm in
fget_unlocked().
 - Save old file descriptor tables created on expansion until
   the entire descriptor table is freed so that pointers may be
   followed without regard for expanders.
 - Mark the file zone as NOFREE so we may attempt to reference
   potentially freed files.
 - Convert several fget_locked() users to fget_unlocked().  This
   requires us to manage reference counts explicitly but reduces
   locking overhead in the common case.
2009-05-14 03:24:22 +00:00
Robert Watson
ae81968fd1 When writing out updated pollfd records when returning from
poll(), only copy out the revents field, not the whole pollfd
structure.  Otherwise, if the events field is updated
concurrently by another thread, that update may be lost.

This issue apparently causes problems for the JDK on FreeBSD,
which expects the Linux behavior of not updating all fields
(somewhat oddly, Solaris does not implement the required
behavior, but presumably our adaptation of the JDK is based
on the Linux port?).

MFC after:      2 weeks
PR:		kern/130924
Submitted by:   Kurt Miller <kurt @ intricatesoftware.com>
Discussed with:	kib
2009-03-11 22:00:03 +00:00
Konstantin Belousov
125dcf8c7d Extract the no_poll() and vop_nopoll() code into the common routine
poll_no_poll().
Return a poll_no_poll() result from devfs_poll_f() when
filedescriptor does not reference the live cdev, instead of ENXIO.

Noted and tested by:	hps
MFC after:	1 week
2009-03-06 15:35:37 +00:00
Stephane E. Potvin
60b7f468da Fix select on platforms where sizeof(long) != sizeof(int). This used
to work by accident before the cleanup done in revision 187693.

Approved by:	kan (mentor)
2009-02-02 03:34:40 +00:00
Jeff Roberson
9cdacff1d3 - bit has to be fd_mask to work properly on 64bit platforms. Constants
must also be cast even though the result ultimately is promoted
   to 64bit.
 - Correct a loop index upper bound in selscan().
2009-01-25 18:38:42 +00:00
Jeff Roberson
748b9df687 - Correct a typo in a comment.
Noticed by:	danger
2009-01-25 09:17:16 +00:00
Jeff Roberson
11b763df19 Fix errors introduced when I rewrote select.
- Restructure selscan() and selrescan() to avoid producing extra selfps
   when we have a fd in multiple sets.  As described below multiple selfps
   may still exist for other reasons.
 - Make selrescan() tolerate multiple selfds for a given descriptor
   set since sockets use two selinfos per fd.  If an event on each selinfo
   fires selrescan() will see the descriptor twice.  This could result in
   select() returning 2x the number of fds actually existing in fd sets.

Reported by:	mgleason@ncftp.com
2009-01-25 07:24:34 +00:00
David E. O'Brien
715457f6f6 Reverse if() logic to improve readability.
Reviewed by:	ru
2008-09-23 14:25:38 +00:00
Jeff Roberson
bd4e153568 - Remove stale comment.
- In the last revision the code was changed to use maxfilesperproc rather than
   the per-process file limit to restrict the size of the poll array.  This
   eliminates a significant source of process lock contention in multithreaded
   programs and is cheaper.  This had been committed with the wrong batch of
   changes.
2008-03-19 07:33:16 +00:00
Jeff Roberson
374ae2a393 - Relax requirements for p_numthreads, p_threads, p_swtick, and p_nice from
requiring the per-process spinlock to only requiring the process lock.
 - Reflect these changes in the proc.h documentation and consumers throughout
   the kernel.  This is a substantial reduction in locking cost for these
   fields and was made possible by recent changes to threading support.
2008-03-19 06:19:01 +00:00
John Baldwin
e46502943a Make ftruncate a 'struct file' operation rather than a vnode operation.
This makes it possible to support ftruncate() on non-vnode file types in
the future.
- 'struct fileops' grows a 'fo_truncate' method to handle an ftruncate() on
  a given file descriptor.
- ftruncate() moves to kern/sys_generic.c and now just fetches a file
  object and invokes fo_truncate().
- The vnode-specific portions of ftruncate() move to vn_truncate() in
  vfs_vnops.c which implements fo_truncate() for vnode file types.
- Non-vnode file types return EINVAL in their fo_truncate() method.

Submitted by:	rwatson
2008-01-07 20:05:19 +00:00
Jeff Roberson
397c19d175 Remove explicit locking of struct file.
- Introduce a finit() which is used to initailize the fields of struct file
   in such a way that the ops vector is only valid after the data, type,
   and flags are valid.
 - Protect f_flag and f_count with atomic operations.
 - Remove the global list of all files and associated accounting.
 - Rewrite the unp garbage collection such that it no longer requires
   the global list of all files and instead uses a list of all unp sockets.
 - Mark sockets in the accept queue so we don't incorrectly gc them.

Tested by:	kris, pho
2007-12-30 01:42:15 +00:00
Jeff Roberson
ace8398da0 Refactor select to reduce contention and hide internal implementation
details from consumers.

 - Track individual selecters on a per-descriptor basis such that there
   are no longer collisions and after sleeping for events only those
   descriptors which triggered events must be rescaned.
 - Protect the selinfo (per descriptor) structure with a mtx pool mutex.
   mtx pool mutexes were chosen to preserve api compatibility with
   existing code which does nothing but bzero() to setup selinfo
   structures.
 - Use a per-thread wait channel rather than a global wait channel.
 - Hide select implementation details in a seltd structure which is
   opaque to the rest of the kernel.
 - Provide a 'selsocket' interface for those kernel consumers who wish to
   select on a socket when they have no fd so they no longer have to
   be aware of select implementation details.

Tested by:	kris
Reviewed on:	arch
2007-12-16 06:21:20 +00:00
Julian Elischer
431f890614 generally we are interested in what thread did something as
opposed to what process. Since threads by default have teh name of the
process unless over-written with more useful information, just print the
thread name instead.
2007-11-14 06:21:24 +00:00
Peter Wemm
c2815ad564 Add freebsd6_ wrappers for mmap/lseek/pread/pwrite/truncate/ftruncate
Approved by: re (kensmith)
2007-07-04 22:57:21 +00:00
Jeff Roberson
982d11f836 Commit 14/14 of sched_lock decomposition.
- Use thread_lock() rather than sched_lock for per-thread scheduling
   sychronization.
 - Use the per-process spinlock rather than the sched_lock for per-process
   scheduling synchronization.

Tested by:      kris, current@
Tested on:      i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
2007-06-05 00:00:57 +00:00
Alan Cox
fa75abb0d2 Remove unneeded include files. 2007-05-01 06:35:54 +00:00
Robert Watson
5e3f7694b1 Replace custom file descriptor array sleep lock constructed using a mutex
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
2007-04-04 09:11:34 +00:00
Robert Watson
873fbcd776 Further system call comment cleanup:
- Remove also "MP SAFE" after prior "MPSAFE" pass. (suggested by bde)
- Remove extra blank lines in some cases.
- Add extra blank lines in some cases.
- Remove no-op comments consisting solely of the function name, the word
  "syscall", or the system call name.
- Add punctuation.
- Re-wrap some comments.
2007-03-05 13:10:58 +00:00
Robert Watson
0c14ff0eb5 Remove 'MPSAFE' annotations from the comments above most system calls: all
system calls now enter without Giant held, and then in some cases, acquire
Giant explicitly.

Remove a number of other MPSAFE annotations in the credential code and
tweak one or two other adjacent comments.
2007-03-04 22:36:48 +00:00
Bruce M Simpson
6f7ca813c4 Do not dispatch SIGPIPE from the generic write path for a socket; with
this patch the code behaves according to the comment on the line above.

Without this patch, a socket could cause SIGPIPE to be delivered to its
process, once with SO_NOSIGPIPE set, and twice without.

With this patch, the kernel now passes the sigpipe regression test.

Tested by:	Anton Yuzhaninov
MFC after:	1 week
2007-03-01 19:20:25 +00:00
Ruslan Ermilov
a1b0a18096 Prevent IOC_IN with zero size argument (this is only supported
if backward copatibility options are present) from attempting
to free memory that wasn't allocated.  This is an old bug, and
previously it would attempt to free a null pointer.  I noticed
this bug when working on the previous revision, but forgot to
fix it.

Security:	local DoS
Reported by:	Peter Holm
MFC after:	3 days
2006-10-14 19:01:55 +00:00
Ruslan Ermilov
9fddcc6661 Fix our ioctl(2) implementation when the argument is "int". New
ioctls passing integer arguments should use the _IOWINT() macro.
This fixes a lot of ioctl's not working on sparc64, most notable
being keyboard/syscons ioctls.

Full ABI compatibility is provided, with the bonus of fixing the
handling of old ioctls on sparc64.

Reviewed by:	bde (with contributions)
Tested by:	emax, marius
MFC after:	1 week
2006-09-27 19:57:02 +00:00
John Baldwin
d9f4623307 - Split ioctl() up into ioctl() and kern_ioctl(). The kern_ioctl() assumes
that the 'data' pointer is already setup to point to a valid KVM buffer
  or contains the copied-in data from userland as appropriate (ioctl(2)
  still does this).  kern_ioctl() takes care of looking up a file pointer,
  implementing FIONCLEX and FIOCLEX, and calling fi_ioctl().
- Use kern_ioctl() to implement xenix_rdchk() instead of using the stackgap
  and mark xenix_rdchk() MPSAFE.
2006-07-08 20:12:14 +00:00
John Baldwin
af56abaab5 Return error from fget_write() rather than hardcoding EBADF now that
fget_write() DTRT.

Requested by:	bde
2006-01-06 16:34:22 +00:00
John Baldwin
e730167f16 Remove XXX comments complaining that write(2) on a read-only descriptor
returns EBADF.  That errno is correct and is mandated by POSIX.  It also
goes back to revision 1.1 of our CVS history (i.e. 4.4BSD).

The _fget() function should probably also be upated as it currently returns
EINVAL in that case rather than EBADF.  (It does return EBADF for reads
on a write-only descriptor without any XXX comments oddly enough.)

Discussed with:	scottl, grog, mjacob, bde
2006-01-05 22:20:31 +00:00
John Baldwin
bcd9e0dd20 - Add two new system calls: preadv() and pwritev() which are like readv()
and writev() except that they take an additional offset argument and do
  not change the current file position.  In SAT speak:
  preadv:readv::pread:read and pwritev:writev::pwrite:write.
- Try to reduce code duplication some by merging most of the old
  kern_foov() and dofilefoo() functions into new dofilefoo() functions
  that are called by kern_foov() and kern_pfoov().  The non-v functions
  now all generate a simple uio on the stack from the passed in arguments
  and then call kern_foov().  For example, read() now just builds a uio and
  calls kern_readv() and pwrite() just builds a uio and calls kern_pwritev().

PR:		kern/80362
Submitted by:	Marc Olzheim marcolz at stack dot nl (1)
Approved by:	re (scottl)
MFC after:	1 week
2005-07-07 18:17:55 +00:00
Peter Wemm
2de92a386e Conditionally weaken sys_generic.c rev 1.136 to allow certain dubious
ioctl numbers in backwards compatability mode.  eg: an IOC_IN ioctl with
a size of zero.  Traditionally this was what you did before IOC_VOID
existed, and we had some established users of this in the tree, namely
procfs.  Certain 3rd party drivers with binary userland components also
have this too.

This is necessary to have 4.x and 5.x binaries use these ioctl's.  We
found this at work when trying to run 4.x binaries.

Approved by:	re
2005-06-30 00:19:08 +00:00
John Baldwin
b88ec951e1 Implement kern_adjtime(), kern_readv(), kern_sched_rr_get_interval(),
kern_settimeofday(), and kern_writev() to allow for further stackgap
reduction in the compat ABIs.
2005-03-31 22:51:18 +00:00
Colin Percival
e5e6a46460 Declare "cnt" (a number of bytes to read or write) as an "ssize_t", not
as a "long" in dofileread() and dofilewrite().

Discussed with:	jhb
2005-02-10 20:19:17 +00:00
Poul-Henning Kamp
4f8d23d662 Previously a read of zero bytes got handled in devfs:vop_read() but I
missed that when the vnode bypass was introduced.

Deal with zero length transfers before we even get to fo_ops->fo_read().

Found by:	Slawa Olhovchenkov <slwzxy.spb.ru@zxy.spb.ru>
PR:	75758
2005-01-25 09:15:32 +00:00
Poul-Henning Kamp
9fc6aa0618 Detect sign-extension bugs in the ioctl(2) command argument: Truncate
to 32 bits and print warning.
2005-01-18 07:37:05 +00:00
Warner Losh
9454b2d864 /* -> /*- for copyright notices, minor format tweaks as necessary 2005-01-06 23:35:40 +00:00
Poul-Henning Kamp
a0fbccc9e7 Push Giant down through ioctl.
Don't grab Giant in the upper syscall/wrapper code

NET_LOCK_GIANT in the socket code (sockets/fifos).

mtx_lock(&Giant) in the vnode code.

mtx_lock(&Giant) in the opencrypto code.  (This may actually not be
needed, but better safe than sorry).

Devfs grabs Giant if the driver is marked as needing Giant.
2004-11-17 09:09:55 +00:00
Poul-Henning Kamp
db446e30cc Push Giant down through select and poll.
Don't grab Giant in the upper syscall/wrapper code

NET_LOCK_GIANT in the socket code (sockets/fifos).

mtx_lock(&Giant) in the vnode code.

Devfs grabs Giant if the driver is marked as needing Giant.
2004-11-17 08:01:10 +00:00
Poul-Henning Kamp
8ccf264fcc Polish code to correctly reflect structure. 2004-11-16 14:47:04 +00:00
Poul-Henning Kamp
ca51b19b18 Rearrange memory management for ioctl arguments to use stronger checks
for illegal values and don't store them on the stack any more.
2004-11-14 14:34:12 +00:00
Poul-Henning Kamp
3e15c66f2a style polish. 2004-11-14 12:04:34 +00:00
Poul-Henning Kamp
124e4c3be8 Introduce an alias for FILEDESC_{UN}LOCK() with the suffix _FAST.
Use this in all the places where sleeping with the lock held is not
an issue.

The distinction will become significant once we finalize the exact
lock-type to use for this kind of case.
2004-11-13 11:53:02 +00:00
Andre Oppermann
2580f4e584 Poll() uses the array smallbits that is big enough to hold 32 struct
pollfd's to avoid calling malloc() on small numbers of fd's.  Because
smalltype's members have type char, its address might be misaligned
for a struct pollfd.  Change the array of char to an array of struct
pollfd.

PR:		kern/58214
Submitted by:	Stefan Farfeleder <stefan@fafoe.narf.at>
Reviewed by:	bde (a long time ago)
MFC after:	3 days
2004-08-27 21:23:50 +00:00
Poul-Henning Kamp
552afd9c12 Clean up and wash struct iovec and struct uio handling.
Add copyiniov() which copies a struct iovec array in from userland into
a malloc'ed struct iovec.  Caller frees.

Change uiofromiov() to malloc the uio (caller frees) and name it
copyinuio() which is more appropriate.

Add cloneuio() which returns a malloc'ed copy.  Caller frees.

Use them throughout.
2004-07-10 15:42:16 +00:00
Warner Losh
7f8a436ff2 Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core
2004-04-05 21:03:37 +00:00
Robert Watson
5d8dd01da2 Add annotations to mtx_lock(&Giant) in kern_select() and poll() that
we always grab Giant, even if we're actually only polling objects that
don't require giant.  Once socket locking is merged, there will be
strong motivation to fix this.
2004-03-13 05:58:57 +00:00
John Baldwin
44f3b09204 Switch the sleep/wakeup and condition variable implementations to use the
sleep queue interface:
- Sleep queues attempt to merge some of the benefits of both sleep queues
  and condition variables.  Having sleep qeueus in a hash table avoids
  having to allocate a queue head for each wait channel.  Thus, struct cv
  has shrunk down to just a single char * pointer now.  However, the
  hash table does not hold threads directly, but queue heads.  This means
  that once you have located a queue in the hash bucket, you no longer have
  to walk the rest of the hash chain looking for threads.  Instead, you have
  a list of all the threads sleeping on that wait channel.
- Outside of the sleepq code and the sleep/cv code the kernel no longer
  differentiates between cv's and sleep/wakeup.  For example, calls to
  abortsleep() and cv_abort() are replaced with a call to sleepq_abort().
  Thus, the TDF_CVWAITQ flag is removed.  Also, calls to unsleep() and
  cv_waitq_remove() have been replaced with calls to sleepq_remove().
- The sched_sleep() function no longer accepts a priority argument as
  sleep's no longer inherently bump the priority.  Instead, this is soley
  a propery of msleep() which explicitly calls sched_prio() before
  blocking.
- The TDF_ONSLEEPQ flag has been dropped as it was never used.  The
  associated TDF_SET_ONSLEEPQ and TDF_CLR_ON_SLEEPQ macros have also been
  dropped and replaced with a single explicit clearing of td_wchan.
  TD_SET_ONSLEEPQ() would really have only made sense if it had taken
  the wait channel and message as arguments anyway.  Now that that only
  happens in one place, a macro would be overkill.
2004-02-27 18:52:44 +00:00
John Baldwin
91d5354a2c Locking for the per-process resource limits structure.
- struct plimit includes a mutex to protect a reference count.  The plimit
  structure is treated similarly to struct ucred in that is is always copy
  on write, so having a reference to a structure is sufficient to read from
  it without needing a further lock.
- The proc lock protects the p_limit pointer and must be held while reading
  limits from a process to keep the limit structure from changing out from
  under you while reading from it.
- Various global limits that are ints are not protected by a lock since
  int writes are atomic on all the archs we support and thus a lock
  wouldn't buy us anything.
- All accesses to individual resource limits from a process are abstracted
  behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return
  either an rlimit, or the current or max individual limit of the specified
  resource from a process.
- dosetrlimit() was renamed to kern_setrlimit() to match existing style of
  other similar syscall helper functions.
- The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit()
  (it didn't used the stackgap when it should have) but uses lim_rlimit()
  and kern_setrlimit() instead.
- The svr4 compat no longer uses the stackgap for resource limits calls,
  but uses lim_rlimit() and kern_setrlimit() instead.
- The ibcs2 compat no longer uses the stackgap for resource limits.  It
  also no longer uses the stackgap for accessing sysctl's for the
  ibcs2_sysconf() syscall but uses kernel_sysctl() instead.  As a result,
  ibcs2_sysconf() no longer needs Giant.
- The p_rlimit macro no longer exists.

Submitted by:	mtm (mostly, I only did a few cleanups and catchups)
Tested on:	i386
Compiled on:	alpha, amd64
2004-02-04 21:52:57 +00:00
Andrey A. Chernov
9bbee25931 pread/pwrite:
follow lseek spirit - return EINVAL on negative offset for non-VCHR
2004-01-20 01:27:42 +00:00
Seigo Tanimura
512824f8f7 - Implement selwakeuppri() which allows raising the priority of a
thread being waken up.  The thread waken up can run at a priority as
  high as after tsleep().

- Replace selwakeup()s with selwakeuppri()s and pass appropriate
  priorities.

- Add cv_broadcastpri() which raises the priority of the broadcast
  threads.  Used by selwakeuppri() if collision occurs.

Not objected in:	-arch, -current
2003-11-09 09:17:26 +00:00
Poul-Henning Kamp
b294143142 Introduce no_poll() default method for device drivers. Have it
do exactly the same as vop_nopoll() for consistency and put a
comment in the two pointing at each other.

Retire seltrue() in favour of no_poll().

Create private default functions in kern_conf.c instead of public
ones.

Change default strategy to return the bio with ENODEV instead of
doing nothing which would lead the bio stranded.

Retire public nullopen() and nullclose() as well as the entire band
of public no{read,write,ioctl,mmap,kqfilter,strategy,poll,dump}
funtions, they are the default actions now.

Move the final two trivial functions from subr_xxx.c to kern_conf.c
and retire the now empty subr_xxx.c
2003-09-27 12:53:33 +00:00
Alan Cox
882d8469af Remove Giant from writev(2). Eliminate trivial style differences between
writev(2) and readv(2).
2003-08-01 02:21:54 +00:00
Poul-Henning Kamp
2db4b023bb Introduce a new flag on a file descriptor: DFLAG_SEEKABLE and use that
rather than assume that only DTYPE_VNODE is seekable.
2003-06-18 19:53:59 +00:00