Commit Graph

190 Commits

Author SHA1 Message Date
Davide Italiano
68cefd64ad The variable 'error' in sys_poll() is initialized in declaration to value
zero but in any case is overwritten by successive copyin(), making the
previous initialization useless. Remove this.
As an added bonus this fixes a style(9) bug.

Discussed with:		kib
Approved by:		gnn (mentor)
MFC after:		3 days
2012-06-17 13:03:50 +00:00
Konstantin Belousov
8bb9a904d5 Instead of incomplete handling of read(2)/write(2) return values that
does not fit into registers, declare that we do not support this case
using CTASSERT(), and remove endianess-unsafe code to split return value
into td_retval.

While there, change the style of the sysctl debug.iosize_max_clamp
definition.

Requested by:	bde
MFC after:	3 weeks
2012-03-04 14:55:37 +00:00
Konstantin Belousov
526d0bd547 Fix found places where uio_resid is truncated to int.
Add the sysctl debug.iosize_max_clamp, enabled by default. Setting the
sysctl to zero allows to perform the SSIZE_MAX-sized i/o requests from
the usermode.

Discussed with:	bde, das (previous versions)
MFC after:	1 month
2012-02-21 01:05:12 +00:00
Konstantin Belousov
56be1b9a7a To limit amount of the kernel memory allocated, and to optimize the
iteration over the fdsets, kern_select() limits the length of the
fdsets copied in by the last valid file descriptor index. If any bit
is set in a mask above the limit, current implementation ignores the
filedescriptor, instead of returning EBADF.

Fix the issue by scanning the tails of fdset before entering the
select loop and returning EBADF if any bit above last valid
filedescriptor index is set. The performance impact of the additional
check is only imposed on the (somewhat) buggy applications that pass
bad file descriptors to select(2) or pselect(2).

PR:	kern/155606, kern/162379
Discussed with:	cognet, glebius
Tested by:	andreast (powerpc, all 64/32bit ABI combinations, big-endian),
       marius (sparc64, big-endian)
MFC after:    2 weeks
2011-11-13 10:28:01 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00
Attilio Rao
6aba400a70 Fix a deficiency in the selinfo interface:
If a selinfo object is recorded (via selrecord()) and then it is
quickly destroyed, with the waiters missing the opportunity to awake,
at the next iteration they will find the selinfo object destroyed,
causing a PF#.

That happens because the selinfo interface has no way to drain the
waiters before to destroy the registered selinfo object. Also this
race is quite rare to get in practice, because it would require a
selrecord(), a poll request by another thread and a quick destruction
of the selrecord()'ed selinfo object.

Fix this by adding the seldrain() routine which should be called
before to destroy the selinfo objects (in order to avoid such case),
and fix the present cases where it might have already been called.
Sometimes, the context is safe enough to prevent this type of race,
like it happens in device drivers which installs selinfo objects on
poll callbacks. There, the destruction of the selinfo object happens
at driver detach time, when all the filedescriptors should be already
closed, thus there cannot be a race.
For this case, mfi(4) device driver can be set as an example, as it
implements a full correct logic for preventing this from happening.

Sponsored by:	Sandvine Incorporated
Reported by:	rstone
Tested by:	pluknet
Reviewed by:	jhb, kib
Approved by:	re (bz)
MFC after:	3 weeks
2011-08-25 15:51:54 +00:00
Jonathan Anderson
d6f7248983 poll(2) implementation for capabilities.
When calling poll(2) on a capability, unwrap first and then poll the
underlying object.

Approved by: re (kib), mentor (rwatson)
Sponsored by: Google Inc
2011-08-16 14:14:56 +00:00
Jonathan Anderson
d1b6899e83 Rename CAP_*_KEVENT to CAP_*_EVENT.
Change the names of a couple of capability rights to be less
FreeBSD-specific.

Approved by: re (kib), mentor (rwatson)
Sponsored by: Google Inc
2011-08-12 14:26:47 +00:00
Robert Watson
a9d2f8d84f Second-to-last commit implementing Capsicum capabilities in the FreeBSD
kernel for FreeBSD 9.0:

Add a new capability mask argument to fget(9) and friends, allowing system
call code to declare what capabilities are required when an integer file
descriptor is converted into an in-kernel struct file *.  With options
CAPABILITIES compiled into the kernel, this enforces capability
protection; without, this change is effectively a no-op.

Some cases require special handling, such as mmap(2), which must preserve
information about the maximum rights at the time of mapping in the memory
map so that they can later be enforced in mprotect(2) -- this is done by
narrowing the rights in the existing max_protection field used for similar
purposes with file permissions.

In namei(9), we assert that the code is not reached from within capability
mode, as we're not yet ready to enforce namespace capabilities there.
This will follow in a later commit.

Update two capability names: CAP_EVENT and CAP_KEVENT become
CAP_POST_KEVENT and CAP_POLL_KEVENT to more accurately indicate what they
represent.

Approved by:	re (bz)
Submitted by:	jonathan
Sponsored by:	Google Inc
2011-08-11 12:30:23 +00:00
Konstantin Belousov
6d8fedda2c For some file types, select code registers two selfd structures. E.g.,
for socket, when specified POLLIN|POLLOUT in events, you would have one
selfd registered for receiving socket buffer, and one for sending. Now,
if both events are not ready to fire at the time of the initial scan,
but are simultaneously ready after the sleep, pollrescan() would iterate
over the pollfd struct twice. Since both times revents is not zero,
returned value would be off by one.

Fix this by recalculating the return value in pollout().

PR:	kern/143029
MFC after:	2 weeks
2010-08-28 17:42:08 +00:00
John Baldwin
7a6f3d7890 Send SIGPIPE to the thread that issued the offending system call
rather than to the entire process.

Reported by:	Anit Chakraborty
Reviewed by:	kib, deischen (concept)
MFC after:	1 week
2010-06-29 20:44:19 +00:00
Konstantin Belousov
61e53a389f Remove PIOLLHUP from the flags used to test for to set exceptfsd
fd_set bits in select(2). It seems that historical behaviour is to not
reporting exception on EOF, and several applications are broken.

Reported by:	Yoshihiko Sarumaru <ysarumaru gmail com>
Discussed with:	bde
PR:	ports/140934
MFC after:	2 weeks
2010-05-21 10:36:29 +00:00
Nathan Whitehorn
841c0c7ec7 Provide groundwork for 32-bit binary compatibility on non-x86 platforms,
for upcoming 64-bit PowerPC and MIPS support. This renames the COMPAT_IA32
option to COMPAT_FREEBSD32, removes some IA32-specific code from MI parts
of the kernel and enhances the freebsd32 compatibility code to support
big-endian platforms.

Reviewed by:	kib, jhb
2010-03-11 14:49:06 +00:00
Konstantin Belousov
066d836b02 Current pselect(3) is implemented in usermode and thus vulnerable to
well-known race condition, which elimination was the reason for the
function appearance in first place. If sigmask supplied as argument to
pselect() enables a signal, the signal might be delivered before thread
called select(2), causing lost wakeup. Reimplement pselect() in kernel,
making change of sigmask and sleep atomic.

Since signal shall be delivered to the usermode, but sigmask restored,
set TDP_OLDMASK and save old mask in td_oldsigmask. The TDP_OLDMASK
should be cleared by ast() in case signal was not gelivered during
syscall execution.

Reviewed by:	davidxu
Tested by:	pho
MFC after:	1 month
2009-10-27 10:55:34 +00:00
Konstantin Belousov
b55ef216fe kern_select(9) copies fd_set in and out of userspace in quantities of
longs. Since 32bit processes longs are 4 bytes, 64bit kernel may copy in
or out 4 bytes more then the process expected.

Calculate the amount of bytes to copy taking into account size of fd_set
for the current process ABI.

Diagnosed and tested by:	Peter Jeremy <peterjeremy acm org>
Reviewed by:	jhb
MFC after:	1 week
2009-09-09 20:59:01 +00:00
Konstantin Belousov
f2159cc790 Fix the conformance of poll(2) for sockets after r195423 by
returning POLLHUP instead of POLLIN for several cases. Now, the
tools/regression/poll results for FreeBSD are closer to that of the
Solaris and Linux.

Also, improve the POSIX conformance by explicitely clearing POLLOUT
when POLLHUP is reported in pollscan(), making the fix global.

Submitted by:	bde
Reviewed by:	rwatson
MFC after:	1 week
2009-08-23 12:44:15 +00:00
Robert Watson
64c9a4d9ab Audit file descriptor and command arguments to ioctl(2).
Approved by:	re (audit argument blanket)
MFC after:	1 week
2009-07-02 09:16:25 +00:00
Jeff Roberson
2141453eb4 - Use fd_lastfile + 1 as the upper bound on nd. This is more correct than
using the size of the descriptor array.
 - A lock is not needed to fetch fd_lastfile.  The results are stale the
   instant it is dropped.
 - Use a private mutex pool for select since the pool mutex is not used
   as a leaf.
 - Fetch the si_mtx pointer first before resorting to hashing to compute
   the mutex address.

Reviewed by:	McKusick
Approved by:	re (kib)
2009-07-01 20:43:46 +00:00
Robert Watson
14961ba789 Replace AUDIT_ARG() with variable argument macros with a set more more
specific macros for each audit argument type.  This makes it easier to
follow call-graphs, especially for automated analysis tools (such as
fxr).

In MFC, we should leave the existing AUDIT_ARG() macros as they may be
used by third-party kernel modules.

Suggested by:	brooks
Approved by:	re (kib)
Obtained from:	TrustedBSD Project
MFC after:	1 week
2009-06-27 13:58:44 +00:00
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