Commit Graph

442 Commits

Author SHA1 Message Date
John Baldwin
1968f37bc9 Tweak some comments. 2013-03-18 18:04:09 +00:00
John Baldwin
3cf3b9f097 Partially revert r195702. Deferring stops is now implemented via a set of
calls to toggle TDF_SBDRY rather than passing PBDRY to individual sleep
calls.
- Remove the stop_allowed parameters from cursig() and issignal().
  issignal() checks TDF_SBDRY directly.
- Remove the PBDRY and SLEEPQ_STOP_ON_BDRY flags.
2013-03-18 17:23:58 +00:00
John Baldwin
593efaf9f7 Further refine the handling of stop signals in the NFS client. The
changes in r246417 were incomplete as they did not add explicit calls to
sigdeferstop() around all the places that previously passed SBDRY to
_sleep().  In addition, nfs_getcacheblk() could trigger a write RPC from
getblk() resulting in sigdeferstop() recursing.  Rather than manually
deferring stop signals in specific places, change the VFS_*() and VOP_*()
methods to defer stop signals for filesystems which request this behavior
via a new VFCF_SBDRY flag.  Note that this has to be a VFC flag rather than
a MNTK flag so that it works properly with VFS_MOUNT() when the mount is
not yet fully constructed.  For now, only the NFS clients are set this new
flag in VFS_SET().

A few other related changes:
- Add an assertion to ensure that TDF_SBDRY doesn't leak to userland.
- When a lookup request uses VOP_READLINK() to follow a symlink, mark
  the request as being on behalf of the thread performing the lookup
  (cnp_thread) rather than using a NULL thread pointer.  This causes
  NFS to properly handle signals during this VOP on an interruptible
  mount.

PR:		kern/176179
Reported by:	Russell Cattelan (sigdeferstop() recursion)
Reviewed by:	kib
MFC after:	1 month
2013-02-21 19:02:50 +00:00
Pawel Jakub Dawidek
6c08be2b88 Add break to the default case. 2013-02-17 11:47:58 +00:00
Konstantin Belousov
888d4d4f86 When vforked child is traced, the debugging events are not generated
until child performs exec().  The behaviour is reasonable when a
debugger is the real parent, because the parent is stopped until
exec(), and sending a debugging event to the debugger would deadlock
both parent and child.

On the other hand, when debugger is not the parent of the vforked
child, not sending debugging signals makes it impossible to debug
across vfork.

Fix the issue by declining generating debug signals only when vfork()
was done and child called ptrace(PT_TRACEME).  Set a new process flag
P_PPTRACE from the attach code for PT_TRACEME, if P_PPWAIT flag is
set, which indicates that the process was created with vfork() and
still did not execed. Check P_PPTRACE from issignal(), instead of
refusing the trace outright for the P_PPWAIT case.  The scope of
P_PPTRACE is exactly contained in the scope of P_PPWAIT.

Found and tested by:  zont
Reviewed by:	pluknet
MFC after:	2 weeks
2013-02-07 15:34:22 +00:00
John Baldwin
a120a7a3cd Rework the handling of stop signals in the NFS client. The changes in
195702, 195703, and 195821 prevented a thread from suspending while holding
locks inside of NFS by forcing the thread to fail sleeps with EINTR or
ERESTART but defer the thread suspension to the user boundary.  However,
this had the effect that stopping a process during an NFS request could
abort the request and trigger EINTR errors that were visible to userland
processes (previously the thread would have suspended and completed the
request once it was resumed).

This change instead effectively masks stop signals while in the NFS client.
It uses the existing TDF_SBDRY flag to effect this since SIGSTOP cannot
be masked directly.  Also, instead of setting PBDRY on individual sleeps,
the NFS client now sets the TDF_SBDRY flag around each NFS request and
stop signals are masked for all sleeps during that region (the previous
change missed sleeps in lockmgr locks).  The end result is that stop
signals sent to threads performing an NFS request are completely
ignored until after the NFS request has finished processing and the
thread prepares to return to userland.  This restores the behavior of
stop signals being transparent to userland processes while still
preventing threads from suspending while holding NFS locks.

Reviewed by:	kib
MFC after:	1 month
2013-02-06 17:06:51 +00:00
Pawel Jakub Dawidek
c345faea5a Replace expand_name() function with corefile_open() function, which not
only returns name, but also vnode of corefile to use.

This simplifies the code and closes few races, especially in %I handling.

Reviewed by:	kib
Obtained from:	WHEEL Systems
2012-12-19 23:59:48 +00:00
Pawel Jakub Dawidek
22a5d85aa9 Use correct file permissions when looking for available core file if
kern.corefile contains %I.

Obtained from:	WHEEL Systems
2012-12-19 23:40:02 +00:00
Pawel Jakub Dawidek
07a8e07896 The 'flags' argument can be modified in vn_open_cred(), so we need to
set it for every loop interation.

Pointed out by:	kib
2012-12-19 12:14:08 +00:00
Pawel Jakub Dawidek
cc58032c44 Do not audit paths we try when kern.corefile contains %I.
Obtained from:	WHEEL Systems
2012-12-19 12:12:53 +00:00
Pawel Jakub Dawidek
29146f1a7a Style cleanups. 2012-12-19 12:10:14 +00:00
Pawel Jakub Dawidek
086053a370 The expand_name() function isn't called with the process lock held anymore,
so we can safely use malloc(M_WAITOK) now.

Pointed out by:	kib
2012-12-19 12:00:09 +00:00
Pawel Jakub Dawidek
f06f465db7 Minor style tweaks.
Obtained from:	WHEEL Systems
2012-12-17 10:51:22 +00:00
Pawel Jakub Dawidek
c52ff61196 Better variables naming in expand_name() to be more consistent with coredump().
Obtained from:	WHEEL Systems
2012-12-17 10:48:10 +00:00
Pawel Jakub Dawidek
dd57ce87eb Move expand_name() after process lock is released.
This fixed panic where we hold mutex (process lock) and try to obtain sleepable
lock (vnode lock in expand_name()). The panic could occur when %I was used
in kern.corefile.

Additionally we avoid expand_name() overhead when coredumps are disabled.

Obtained from:	WHEEL Systems
2012-12-16 14:53:27 +00:00
Pawel Jakub Dawidek
2ce1b32df2 Don't add audit record when coredumps are disabled or name cannot be expanded.
Discussed with:	rwatson
Obtained from:	WHEEL Systems
2012-12-16 14:24:59 +00:00
Pawel Jakub Dawidek
7e73ee85ab Make the check easier to read.
Obtained from:	WHEEL Systems
2012-12-16 14:14:18 +00:00
Pawel Jakub Dawidek
b039f8c2aa Use 'cred' variable.
Obtained from:	WHEEL Systems
2012-12-16 13:56:38 +00:00
Pawel Jakub Dawidek
b0c9d4d70e Add kern.capmode_coredump sysctl/tunable to allow processes in capability mode
to dump core.

Reviewed by:	rwatson
Obtained from:	WHEEL Systems
MFC after:	2 weeks
2012-11-27 10:38:11 +00:00
Pawel Jakub Dawidek
8890f5d020 Allow to use kill(2) in capability mode, but process can send a signal only
to himself. For example abort(3) at first tries to do kill(getpid(), SIGABRT)
which was failing in capability mode, so the code was failing back to exit(1).

Reviewed by:	rwatson
Obtained from:	WHEEL Systems
MFC after:	2 weeks
2012-11-27 10:22:40 +00:00
Pawel Jakub Dawidek
b62d05fcf9 Allow to modify kern.sugid_coredump and kern.corefile from loader.conf.
Obtained from:	WHEEL Systems
2012-11-27 10:16:48 +00:00
Pawel Jakub Dawidek
c320984687 More style fixes. 2012-11-27 10:15:58 +00:00
Pawel Jakub Dawidek
23c6445a4b Style fixes (mostly whitespaces). 2012-11-27 10:11:54 +00:00
Konstantin Belousov
5050aa86cf Remove the support for using non-mpsafe filesystem modules.
In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.

The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.

Conducted and reviewed by:	attilio
Tested by:	pho
2012-10-22 17:50:54 +00:00
Eitan Adler
3d74f47b90 Correct the killpg(2) return values:
Return EPERM if processes were found but they
were unable to be signaled.

Return the first error from p_cansignal if no signal was successful.

Reviewed by:	jilles
Approved by:	cperciva
MFC after:	1 week
2012-10-22 03:43:02 +00:00
Eitan Adler
10950e4651 Colin acked the wrong diff originally. fixed version coming soon.
Approved by:	cperciva (implicit)
2012-10-22 03:36:44 +00:00
Eitan Adler
2a1c0e4d4e Correct the killpg(2) return values:
Return EPERM if processes were found but they
were unable to be signaled.

Return the first error from p_cansignal if no signal was successful.

Reviewed by:	jilles
Approved by:	cperciva
MFC after:	1 week
2012-10-22 03:34:43 +00:00
John Baldwin
0f14f15b62 Ignore stop and continue signals sent to an exiting process. Stop signals
set p_xstat to the signal that triggered the stop, but p_xstat is also
used to hold the exit status of an exiting process.  Without this change,
a stop signal that arrived after a process was marked P_WEXIT but before
it was marked a zombie would overwrite the exit status with the stop signal
number.

Reviewed by:	kib
MFC after:	1 week
2012-09-13 15:51:18 +00:00
Konstantin Belousov
888aefef89 Deliver SIGSYS to the guilty thread, not to the process.
MFC after:	1 week
2012-08-18 18:17:10 +00:00
David Xu
7ce60f6013 Always clear p_xthread if current thread no longer needs it, in theory, if
debugger exited without calling ptrace(PT_DETACH), there is a time window
that the p_xthread may be pointing to non-existing thread, in practical,
this is not a problem because child process soon will be killed by parent
process.
2012-07-10 05:45:13 +00:00
Konstantin Belousov
2dd9ea6f70 Add thread-private flag to indicate that error value is already placed
in td_errno. Flag is supposed to be used by syscalls returning
EJUSTRETURN because errno was already placed into the usermode frame
by a call to set_syscall_retval(9). Both ktrace and dtrace get errno
value from td_errno if the flag is set.

Use the flag to fix sigsuspend(2) error return ktrace records.

Requested by:	bde
MFC after:	1 week
2012-04-12 10:48:43 +00:00
Jilles Tjoelker
8a8be77610 Remove unused and wrong SA_PROC internal signal property.
The SA_PROC signal property indicated whether each signal number is directed
at a specific thread or at the process in general. However, that depends on
how the signal was generated and not on the signal number. SA_PROC was not
used.
2012-04-09 21:58:58 +00:00
Ed Schouten
6472ac3d8a Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs.
The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.
2011-11-07 15:43:11 +00:00
Sergey Kandaurov
c241c5e49a Fix arguments list for proc:::signal-discard DTrace probe.
Reported by:	Anton Yuzhaninov <citrin citrin ru>
MFC after:	1 week
2011-10-28 15:22:51 +00:00
Konstantin Belousov
8e9a54ee46 The sigwait(3) function shall not return EINTR, according to the
POSIX/SUSvN. The sigwait(2) syscall does return EINTR, and libc.so.7
contains the wrapper sigwait(3) which hides EINTR from callers.  The
EINTR return is used by libthr to handle required cancellation point
in the sigwait(3).

To help the binaries linked against pre-libc.so.7, i.e. RELENG_6 and
earlier, to have right ABI for sigwait(3), transform EINTR return from
sigwait(2) into ERESTART.

Discussed with:	davidxu
MFC after:	1 week
2011-10-01 10:18:55 +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
Jonathan Anderson
cfb5f76865 Add experimental support for process descriptors
A "process descriptor" file descriptor is used to manage processes
without using the PID namespace. This is required for Capsicum's
Capability Mode, where the PID namespace is unavailable.

New system calls pdfork(2) and pdkill(2) offer the functional equivalents
of fork(2) and kill(2). pdgetpid(2) allows querying the PID of the remote
process for debugging purposes. The currently-unimplemented pdwait(2) will,
in the future, allow querying rusage/exit status. In the interim, poll(2)
may be used to check (and wait for) process termination.

When a process is referenced by a process descriptor, it does not issue
SIGCHLD to the parent, making it suitable for use in libraries---a common
scenario when using library compartmentalisation from within large
applications (such as web browsers). Some observers may note a similarity
to Mach task ports; process descriptors provide a subset of this behaviour,
but in a UNIX style.

This feature is enabled by "options PROCDESC", but as with several other
Capsicum kernel features, is not enabled by default in GENERIC 9.0.

Reviewed by: jhb, kib
Approved by: re (kib), mentor (rwatson)
Sponsored by: Google Inc
2011-08-18 22:51:30 +00:00
Edward Tomasz Napierala
b8fdb0d94d Fix support for RACCT_CORE by merging forgotten file. 2011-05-26 18:54:07 +00:00
Jilles Tjoelker
6100955206 ktrace: Log the code for all signals (PSIG events).
The code provides information on how the signal was generated.

Formerly, the code was only logged for traps, much like only signal handlers
for traps received a meaningful si_code before FreeBSD 7.0.

In rare cases, no information is available and 0 is still logged.

MFC after:	1 week
2011-04-17 14:38:11 +00:00
John Baldwin
e806d352d2 Fix several places to ignore processes that are not yet fully constructed.
MFC after:	1 week
2011-04-06 17:47:22 +00:00
John Baldwin
c3b127e022 Small style fix. 2011-03-23 13:44:32 +00:00
Konstantin Belousov
6fa39a7327 Allow debugger to specify that children of the traced process should be
automatically traced. Extend the ptrace(PL_LWPINFO) to report that child
just forked.

Reviewed by:	davidxu, jhb
MFC after:	2 weeks
2011-01-25 10:59:21 +00:00
David Xu
407af02b6e In kern_sigtimedwait(), move initialization code out of process lock,
instead of using SIGISMEMBER to test every interesting signal, just
unmask the signal set and let cursig() return one, get the signal
after it returns, call reschedule_signal() after signals are blocked
again.

In kern_sigprocmask(), don't call reschedule_signal() when it is
unnecessary.

In reschedule_signal(), replace SIGISEMPTY() + SIGISMEMBER() with
sig_ffs(), rename variable 'i' to sig.
2010-10-14 08:01:33 +00:00
David Xu
fc4ecc1d48 sigqueue_collect_set() is no longer needed because other functions
maintain pending set correctly.
2010-10-13 06:28:40 +00:00
David Xu
cf7d9a8ca8 Create a global thread hash table to speed up thread lookup, use
rwlock to protect the table. In old code, thread lookup is done with
process lock held, to find a thread, kernel has to iterate through
process and thread list, this is quite inefficient.
With this change, test shows in extreme case performance is
dramatically improved.

Earlier patch was reviewed by: jhb, julian
2010-10-09 02:50:23 +00:00
Matthew D Fleming
4d369413e1 Replace sbuf_overflowed() with sbuf_error(), which returns any error
code associated with overflow or with the drain function.  While this
function is not expected to be used often, it produces more information
in the form of an errno that sbuf_overflowed() did.
2010-09-10 16:42:16 +00:00
David Xu
137cf33d5e rescure comments from RELENG_4. 2010-09-01 01:26:07 +00:00
David Xu
83b718eb07 If a process is being debugged, skips job control caused by SIGSTOP/SIGCONT
signals, because it is managed by debugger, however a normal signal sent to
a interruptibly sleeping thread wakes up the thread so it will handle the
signal when the process leaves the stopped state.

PR:	150138
MFC after:	1 week
2010-08-31 07:15:50 +00:00
Rui Paulo
79856499bd Add an extra comment to the SDT probes definition. This allows us to get
use '-' in probe names, matching the probe names in Solaris.[1]

Add userland SDT probes definitions to sys/sdt.h.

Sponsored by:	The FreeBSD Foundation
Discussed with:	rwaston [1]
2010-08-22 11:18:57 +00:00
David Xu
212bc4b337 Fix function name in error messages. 2010-07-20 02:23:12 +00:00