This will provide a slightly better smoking gun than just stating
"can't remove non-dynamic nodes!" when calling sysctl_ctx_free(9)
and sysctl_remove_{name,oid}(9) with a non-dynamic (likely
static) sysctl.
MFC after: 1 week
Sponsored by: Dell EMC Isilon
I'm currently working on writing a metrics exporter for the Prometheus
monitoring system to provide access to sysctl metrics. Prometheus and
sysctl have some structural differences:
- sysctl is a tree of string component names.
- Prometheus uses a flat namespace for its metrics, but allows you to
attach labels with values to them, so that you can do aggregation.
An initial version of my exporter simply translated
hw.acpi.thermal.tz1.temperature
to
sysctl_hw_acpi_thermal_tz1_temperature_celcius
while we should ideally have
sysctl_hw_acpi_thermal_temperature_celcius{thermal_zone="tz1"}
allowing you to graph all thermal zones on a system in one go.
The change presented in this commit adds support for accomplishing this,
by providing the ability to attach labels to nodes. In the example I
gave above, the label "thermal_zone" would be attached to "tz1". As this
is a feature that will only be used very rarely, I decided to not change
the KPI too aggressively.
Discussed on: hackers@
Reviewed by: cem
Differential Revision: https://reviews.freebsd.org/D8775
Because the size of bool can be implementation defined, make a bool
sysctl handler which handle bools. Userspace sees the bools like
unsigned 8-bit integers. Values are filtered to either 1 or 0 upon
read and write, similar to what a compiler would do.
Requested by: kmacy @
Sponsored by: Mellanox Technologies
The fail point handler may sleep, but this is not permitted while holding a
rm read lock.
MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division
Use the right intmax_t type instead of intptr_t in a few remaining
places.
Add support for CTLFLAG_TUN for the new fixed with types. Bruce will be
upset that the new handlers silently truncate tuned quad-sized inputs,
but so do all of the existing handlers.
Add the new types to debug_dump_node, for whatever use that is.
Bump FreeBSD_version again, for good measure. We are changing
SYSCTL_HANDLER_ARGS and a member of struct sysctl_oid to intmax_t.
Correct the sysctl typed NULL values for the fixed-width types. (Hat
tip: hps@.)
Suggested by: hps (partial)
Sponsored by: EMC / Isilon Storage Division
Add S8, S16, S32, and U32 types; add SYSCTL*() macros for them, as well
as for the existing 64-bit types. (While SYSCTL*QUAD and UQUAD macros
already exist, they do not take the same sort of 'val' parameter that
the other macros do.)
Clean up the documented "types" in the sysctl.9 document. (These are
macros and thus not real types, but the manual page documents intent.)
The sysctl_add_oid(9) arg2 has been bumped from intptr_t to intmax_t to
accommodate 64-bit types on 32-bit pointer architectures.
This is just the kernel support piece; the userspace sysctl(1) support
will follow in a later patch.
Submitted by: Ravi Pokala <rpokala@panasas.com>
Reviewed by: cem
Relnotes: no
Sponsored by: Panasas
Differential Revision: https://reviews.freebsd.org/D4091
Right now there is a chance that sysctl unregister will cause reader to
block on the sx lock associated with sysctl rmlock, in which case kernels
with debug enabled will panic.
pointer is NULL, as in that case there are no userland pages that
could potentially be wired. It is common for old to be NULL and
oldlenp to be non-NULL in calls to userland_sysctl(), as this is used
to probe for the length of a variable-length sysctl entry before
retrieving a value. Note that it is typical for such calls to be made
with an uninitialized value in *oldlenp, so sysctlmemlock was
essentially being acquired at random (depending on the uninitialized
value in *oldlenp being > PAGE_SIZE or not) for these calls prior to
this patch.
Differential Revision: https://reviews.freebsd.org/D2987
Reviewed by: mjg, kib
Approved by: jmallett (mentor)
MFC after: 1 month
number of dynamically created and destroyed SYSCTLs during runtime it
is very likely that the current new OID number limit of 0x7fffffff can
be reached. Especially if dynamic OID creation and destruction results
from automatic tests. Additional changes:
- Optimize the typical use case by decrementing the next automatic OID
sequence number instead of incrementing it. This saves searching time
when inserting new OIDs into a fresh parent OID node.
- Add simple check for duplicate non-automatic OID numbers.
MFC after: 1 week
strings returned to userland include the nulterm byte.
Some uses of sbuf_new_for_sysctl() write binary data rather than strings;
clear the SBUF_INCLUDENUL flag after calling sbuf_new_for_sysctl() in
those cases. (Note that the sbuf code still automatically adds a nulterm
byte in sbuf_finish(), but since it's not included in the length it won't
get copied to userland along with the binary data.)
Remove explicit adding of a nulterm byte in a couple places now that it
gets done automatically by the sbuf drain code.
PR: 195668
indiscriminately to printf() and freeenv() is incorrect. Add a NULL
check before freeenv(); as for printf(), we could use req.newptr
instead, but we'd have to select the correct format string based on
the type, and that's too much work for an error message, so just
remove it.
in userland rename in-kernel getenv()/setenv() to kern_setenv()/kern_getenv().
This fixes a namespace collision with libc symbols.
Submitted by: kmacy
Tested by: make universe
getenv_xxx() functions instead of strtoq(), because the getenv_xxx()
functions include wrappers for various postfixes like G/M/K, which
strtoq() doesn't do.
These changes prevent sysctl(8) from returning proper output,
such as:
1) no output from sysctl(8)
2) erroneously returning ENOMEM with tools like truss(1)
or uname(1)
truss: can not get etype: Cannot allocate memory
there is an environment variable which shall initialize the SYSCTL
during early boot. This works for all SYSCTL types both statically and
dynamically created ones, except for the SYSCTL NODE type and SYSCTLs
which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to
be used in the case a tunable sysctl has a custom initialisation
function allowing the sysctl to still be marked as a tunable. The
kernel SYSCTL API is mostly the same, with a few exceptions for some
special operations like iterating childrens of a static/extern SYSCTL
node. This operation should probably be made into a factored out
common macro, hence some device drivers use this. The reason for
changing the SYSCTL API was the need for a SYSCTL parent OID pointer
and not only the SYSCTL parent OID list pointer in order to quickly
generate the sysctl path. The motivation behind this patch is to avoid
parameter loading cludges inside the OFED driver subsystem. Instead of
adding special code to the OFED driver subsystem to post-load tunables
into dynamically created sysctls, we generalize this in the kernel.
Other changes:
- Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask"
to "hw.pcic.intr_mask".
- Removed redundant TUNABLE statements throughout the kernel.
- Some minor code rewrites in connection to removing not needed
TUNABLE statements.
- Added a missing SYSCTL_DECL().
- Wrapped two very long lines.
- Avoid malloc()/free() inside sysctl string handling, in case it is
called to initialize a sysctl from a tunable, hence malloc()/free() is
not ready when sysctls from the sysctl dataset are registered.
- Bumped FreeBSD version to indicate SYSCTL API change.
MFC after: 2 weeks
Sponsored by: Mellanox Technologies
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.
MFC after: 3 weeks
in the sysctl_root().
Note: SYSCTL_VNET_* macros can be removed as well. All is
needed to virtualize a sysctl oid is set CTLFLAG_VNET on it.
But for now keep macros in place to avoid large code churn.
Sponsored by: Nginx, Inc.
kernel.
When access restrictions are added to a page table entry, we flush the
corresponding virtual address mapping from the TLB. In contrast, when
access restrictions are removed from a page table entry, we do not
flush the virtual address mapping from the TLB. This is exactly as
recommended in AMD's documentation. In effect, when access
restrictions are removed from a page table entry, AMD's MMUs will
transparently refresh a stale TLB entry. In short, this saves us from
having to perform potentially costly TLB flushes. In contrast,
Intel's MMUs are allowed to generate a spurious page fault based upon
the stale TLB entry. Usually, such spurious page faults are handled
by vm_fault() without incident. However, when we are executing
no-fault sections of the kernel, we are not allowed to execute
vm_fault(). This change introduces special-case handling for spurious
page faults that occur in no-fault sections of the kernel.
In collaboration with: kib
Tested by: gibbs (an earlier version)
I would also like to acknowledge Hiroki Sato's assistance in
diagnosing this problem.
MFC after: 1 week
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)
may be jointly referenced via the mask CTLFLAG_CAPRW. Sysctls with these
flags are available in Capsicum's capability mode; other sysctl nodes are
not.
Flag several useful sysctls as available in capability mode, such as memory
layout sysctls required by the run-time linker and malloc(3). Also expose
access to randomness and available kernel features.
A few sysctls are enabled to support name->MIB conversion; these may leak
information to capability mode by virtue of providing resolution on names
not flagged for access in capability mode. This is, generally, not a huge
problem, but might be something to resolve in the future. Flag these cases
with XXX comments.
Submitted by: jonathan
Sponsored by: Google, Inc.
should not change. Fetch the td_user_pri under the thread lock. This
is probably not necessary but a magic number also seems preferable to
knowing the implementation details here.
Requested by: Jason Behmer < jason DOT behmer AT isilon DOT com >
- entirely eliminate some calls to uio_yeild() as being unnecessary,
such as in a sysctl handler.
- move should_yield() and maybe_yield() to kern_synch.c and move the
prototypes from sys/uio.h to sys/proc.h
- add a slightly more generic kern_yield() that can replace the
functionality of uio_yield().
- replace source uses of uio_yield() with the functional equivalent,
or in some cases do not change the thread priority when switching.
- fix a logic inversion bug in vlrureclaim(), pointed out by bde@.
- instead of using the per-cpu last switched ticks, use a per thread
variable for should_yield(). With PREEMPTION, the only reasonable
use of this is to determine if a lock has been held a long time and
relinquish it. Without PREEMPTION, this is essentially the same as
the per-cpu variable.
sbuf_new_for_sysctl(9). This allows using an sbuf with a SYSCTL_OUT
drain for extremely large amounts of data where the caller knows that
appropriate references are held, and sleeping is not an issue.
Inspired by: rwatson
unfunctional. Wiring the user buffer has only been done explicitly
since r101422.
Mark the kern.disks sysctl as MPSAFE since it is and it seems to have
been mis-using the NOLOCK flag.
Partially break the KPI (but not the KBI) for the sysctl_req 'lock'
field since this member should be private and the "REQ_LOCKED" state
seems meaningless now.
