linux(4): Remove sys/cdefs.h inclusion where it's not needed due to 685dc743

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

linux(4): Use pwd_altroot() to tell namei() about ABI root path

PR: 72920
Differential Revision: https://reviews.freebsd.org/D40090
MFC after: 2 month

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

linux(4): Cleanup includes under compat/linux

Cleanup unneeded includes, sort the rest according to style(9).
No functional changes.

MFC after: 2 weeks

linux: Make compat.linux.preserve_vstatus default to 1

From a user point of view, this makes ^T work out of the box.

Reviewed By: debdrup (man page)
Sponsored By: EPSRC
Differential Revision: https://reviews.freebsd.org/D33842

Change the return type of sv__setid_allowed from bool to int

to please some userspace code using sys/sysent.h.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

linuxolator: Add compat.linux.setid_allowed knob

PR: 21463
Reported by: kris
Reviewed by: dchagin
Tested by: trasz
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D28154

- add more linux socket options (sorted by value)
- map those IPv4 / IPv6 socket options which exist in FreeBSD
+ most of them visually verified to have the same type/layout of arguments
+ not tested with linux programs to behave as intended
- be more human readable for known options which are not handled
- be more verbose for unhandled socket message flags we know about
- print the jail ID in linux_msg if run in a jail
- add possibility to print debug message about known missing parts only once
- add multiple levels of sysctl linux.debug:
1: print debug messages, tell about unimplemented stuff (only once)
2: like 1, but also print messages about implemented but not tested
stuff (only once)
3+: like 2, but no rate limiting of messages
- increase default linux debug level from 1 to 3

We are a lot more verbose in as we need to be (e.g. some of the IP socket
options which are the same, and share the same memory layout, and are
believed to work). The reason is that we have no good testsuite to test those
linux-bits. The LTP or other test suites like the python one, are not fully
up to the task we need. As such the excessive messages about emulated but not
tested socket options.

IMO any MFC (possible, but most probably not by me) should set the default
debug level to 1.

Discussed with: trasz

Add compat.linux.dummy_rlimits, and disable by default.

Turns out the dummy rlimits fix prlimit(1), but break su(8)
(login-1:4.5-1ubuntu2) - although not sudo(8), for some reason.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D26814

Set default stack size for Linux apps to 8MB. This matches Linux'
defaults, makes core files smaller, and fixes applications which use
pthread_join(3) in a wrong way, namely Steam.

This is based on a patch submitted by Jason Yang, which I've reworked
to set the limit instead of only changing the value reported (which
is enough to fix the bug for Linux pthreads, but could be confusing).

PR: 248225
Submitted by: Jason_YH_Yang at wistron.com (earlier version)
Analyzed by: Alex S <iwtcex@gmail.com>
Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D26778

linux: add sysctl compat.linux.use_emul_path

This is a step towards facilitating jails with only Linux binaries.
Supporting emul_path adds path lookups which are completely spurious
if the binary at hand runs in a Linux-based root directory.

It defaults to on (== current behavior).

make -C /root/linux-5.3-rc8 -s -j 1 bzImage:

use_emul_path=1: 101.65s user 68.68s system 100% cpu 2:49.62 total
use_emul_path=0: 101.41s user 64.32s system 100% cpu 2:45.02 total

Add compat.linux.debug sysctl, to make it possible to silence down
the debug messages. While here, clean up some variable naming.

Reviewed by: bcr (manpages), emaste
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D25230

Make linux(4) set the openfiles soft resource limit to 1024 for Linux
applications, which often depend on this being the case. There's a new
sysctl, compat.linux.default_openfiles, to control this behaviour.

Reviewed by: kevans, emaste, bcr (manpages)
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D25177

Move compat.linux.map_sched_prio sysctl definition to linux_mib.c so it is
only defined by linux_common kernel module and not both linux and linux64
modules.

Reported by: Yuri Pankov <ypankov@fastmail.com>

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.

This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.

Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT

Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718

Add compat.linux.ignore_ip_recverr sysctl. This is a workaround
for missing IP_RECVERR setsockopt(2) support. Without it, DNS
resolution is broken for glibc >= 2.30 (glibc BZ #24047).

From the user point of view this fixes "yum update" on recent
CentOS 8.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23234

Add a hack to make ^T work for Linux binaries, enabled with
'compat.linux.preserve_vstatus=1' sysctl.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21967

Relax compat.linux.osrelease checks. This way one can do eg
'compat.linux.osrelease=3.10.0-957.12.1.el7.x86_64', which
corresponds to CentOS 7.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20685

Fix the Linux kernel version number calculation

The Linux compatibility code was converting the version number (e.g.
2.6.32) in two different ways and then comparing the results.

The linux_map_osrel() function converted MAJOR.MINOR.PATCH similar to
what FreeBSD does natively. I.e. where major=v0, minor=v1, and patch=v2
v = v0 * 1000000 + v1 * 1000 + v2;

The LINUX_KERNVER() macro, on the other hand, converted the value with
bit shifts. I.e. where major=a, minor=b, and patch=c
v = (((a) << 16) + ((b) << 8) + (c))

The Linux kernel uses the later format via the KERNEL_VERSION() macro in
include/generated/uapi/linux/version.h

Fix is to use the LINUX_KERNVER() macro in linux_map_osrel() as well as
in the .trans_osrel functions.

PR: 229209
Reviewed by: emaste, cem, imp (mentor)
Approved by: imp (mentor)
Differential Revision: https://reviews.freebsd.org/D15952

Correct proper nouns in the Linuxulator

- Capitalize Linux
- Spell FreeBSD out in full
- Address some style(9) on changed lines

Sponsored by: Turing Robotic Industries Inc.

Rationalize license text on Linuxolator files

Many licenses on Linuxolator files contained small variations from the
standard FreeBSD license text. To avoid license proliferation switch to
the standard 2-clause FreeBSD license for those files where I have
permission from each of the listed copyright holders. Additional files
waiting on permission from others are listed in review D14210.

Approved by: kan, marcel, sos, rdivacky
MFC after: 1 week
Sponsored by: The FreeBSD Foundation

sys/compat: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

osd(9): Change array pointer to array pointer type from void*

This is a minor follow-up to r297422, prompted by a Coverity warning. (It's
not a real defect, just a code smell.) OSD slot array reservations are an
array of pointers (void **) but were cast to void* and back unnecessarily.
Keep the correct type from reservation to use.

osd.9 is updated to match, along with a few trivial igor fixes.

Reported by: Coverity
CID: 1353811
Sponsored by: EMC / Isilon Storage Division

linux_map_osrel doesn't need to be checked in linux_prison_set,
since it already was in linux_prison_check.

Use osd_reserve / osd_jail_set_reserved, which is known to succeed.
Also don't work around nonexistent osd_register failure.

Introduce a new module linux_common.ko which is intended for the
following primary purposes:

1. Remove the dependency of linsysfs and linprocfs modules from linux.ko,
which will be architecture specific on amd64.

2. Incorporate into linux_common.ko general code for platforms on which
we'll support two Linuxulator modules (for both instruction set - 32 & 64 bit).

3. Move malloc(9) declaration to linux_common.ko, to enable getting memory
usage statistics properly.

Currently linux_common.ko incorporates a code from linux_mib.c and linux_util.c
and linprocfs, linsysfs and linux kernel modules depend on linux_common.ko.

Temporarily remove dtrace garbage from linux_mib.c and linux_util.c

Differential Revision: https://reviews.freebsd.org/D1072
In collaboration with: Vassilis Laganakos.

Reviewed by: trasz

Introduce LINUX_VERSION_STR, LINUX_VERSION_CODE macro for use instead
of harcoded pr_osrelease, pr_osrel values. This will be used later in
the VDSO.

Differential Revision: https://reviews.freebsd.org/D1042
Reviewed by: trasz

Bump minimum linux compat version to support Centos6 ports updates for linux.

Update linux compat minimum revision to match linux-c6 now in ports. This
is a candidate for 10.1 R as it matches the current state of supported
linux compat packages in the ports tree.

PR: 187786
Reviewed by: xmj
MFC after: 2 days
Relnotes: yes

- For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the inlined
version of the releasing functions for mutex, rwlock and sxlock.
Failing to do so skips the lockstat_probe_func invokation for
unlocking.
- As part of the LOCKSTAT support is inlined in mutex operation, for
kernel compiled without lock debugging options, potentially every
consumer must be compiled including opt_kdtrace.h.
Fix this by moving KDTRACE_HOOKS into opt_global.h and remove the
dependency by opt_kdtrace.h for all files, as now only KDTRACE_FRAMES
is linked there and it is only used as a compile-time stub [0].

[0] immediately shows some new bug as DTRACE-derived support for debug
in sfxge is broken and it was never really tested. As it was not
including correctly opt_kdtrace.h before it was never enabled so it
was kept broken for a while. Fix this by using a protection stub,
leaving sfxge driver authors the responsibility for fixing it
appropriately [1].

Sponsored by: EMC / Isilon storage division
Discussed with: rstone
[0] Reported by: rstone
[1] Discussed with: philip

Reduce duplication between i386/linux/linux.h and amd64/linux32/linux.h
by moving bits that are MI out into headers in compat/linux.

Reviewed by: Chagin Dmitry dmitry | gmail
MFC after: 2 weeks

- >500 static DTrace probes for the linuxulator
- DTrace scripts to check for errors, performance, ...
they serve mostly as examples of what you can do with the static probe;s
with moderate load the scripts may be overwhelmed, excessive lock-tracing
may influence program behavior (see the last design decission)

Design decissions:
- use "linuxulator" as the provider for the native bitsize; add the
bitsize for the non-native emulation (e.g. "linuxuator32" on amd64)
- Add probes only for locks which are acquired in one function and released
in another function. Locks which are aquired and released in the same
function should be easy to pair in the code, inter-function
locking is more easy to verify in DTrace.
- Probes for locks should be fired after locking and before releasing to
prevent races (to provide data/function stability in DTrace, see the
man-page of "dtrace -v ..." and the corresponding DTrace docs).

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.

Staticize functions which are not used somewhere else, move the
corresponding prototypes from the header to the code file.

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Some jail parameters (in particular, "ip4" and "ip6" for IP address
restrictions) were found to be inadequately described by a boolean.
Define a new parameter type with three values (disable, new, inherit)
to handle these and future cases.

Approved by: re (kib), bz (mentor)
Discussed with: rwatson

Add hierarchical jails. A jail may further virtualize its environment
by creating a child jail, which is visible to that jail and to any
parent jails. Child jails may be restricted more than their parents,
but never less. Jail names reflect this hierarchy, being MIB-style
dot-separated strings.

Every thread now points to a jail, the default being prison0, which
contains information about the physical system. Prison0's root
directory is the same as rootvnode; its hostname is the same as the
global hostname, and its securelevel replaces the global securelevel.
Note that the variable "securelevel" has actually gone away, which
should not cause any problems for code that properly uses
securelevel_gt() and securelevel_ge().

Some jail-related permissions that were kept in global variables and
set via sysctls are now per-jail settings. The sysctls still exist for
backward compatibility, used only by the now-deprecated jail(2) system
call.

Approved by: bz (mentor)

Introduce linux_kernver() interface which is intended for an exact
designation of the emulated kernel version.

linux_kernver() returns integer value formatted as 'VVVMMMIII' where
VVV - version, MMM - major revision, III - minor revision.

Approved by: kib (mentor)

Give vfs_getopt the type it's expecting.
Write 100 times: "32 bits is so twentieth century."

Noticed by: dchagin

Move the per-prison Linux MIB from a private one-off pointer to the new
OSD-based jail extensions. This allows the Linux MIB to accessed via
jail_set and jail_get, and serves as a demonstration of adding jail support
to a module.

Reviewed by: dchagin, kib
Approved by: bz (mentor)

Add preliminary KTR(9) support to the linux emulation layer.

Approved by: kib (mentor)
MFC after: 1 month

Mark Linux MIB sysctls MPSAFE.

Reviewed by: dchagin, kib
Approved by: bz (mentor)

- Import the HEAD csup code which is the basis for the cvsmode work.

Switch to emulating Linux 2.6 on default.

Approved by: kib (mentor)

MFp4 (112705):
Inherit setting of the default emulation version to the jails.

Pointed out by: jhb
Submitted by: rdivacky

MFp4 (112535):
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

MFp4 (111746+):
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

Unbreak COMPAT_LINUX32 option support on amd64.

Broken by: netchild

Fixup some problems in my previous commit (COMPAT_43).

Pointyhat to: netchild

Remove linux_mib_destroy() (which I actually added in between 5.0 and 5.1)
which existed to cleanup the linux_osname mutex. Now that MTX_SYSINIT()
has grown a SYSUNINIT to destroy mutexes on unload, the extra destroy here
was redundant and resulted in panics in debug kernels.

MFC after: 1 week
Reported by: Goran Gajic ggajic at afrodita dot rcub dot bg dot ac dot yu

Match the LINUX32's style with existing style
Submitted by: Jung-uk Kim <jkim@niksun.com>

Use positive, not negative logic.

Changes to MI Linux emulation code necessary to run 32-bit Linux binaries
on AMD64, and the general case where the emulated platform has different
size pointers than we use natively:
- declare certain structure members as l_uintptr_t and use the new PTRIN
and PTROUT macros to convert to and from native pointers.
- declare some structures __packed on amd64 when the layout would differ
from that used on i386.
- include <machine/../linux32/linux.h> instead of <machine/../linux/linux.h>
if compiling with COMPAT_LINUX32. This will need to be revisited before
32-bit and 64-bit Linux emulation support can coexist in the same kernel.
- other small scattered changes.

This should be a no-op on i386 and Alpha.

Use __FBSDID().

Add a cleanup function to destroy the osname_lock and call it on module
unload.

Submitted by: gallatin
Reported by: Martin Karlsson <mk-freebsd@bredband.net>

- Change the linux_[gs]et_os{name, release, s_version}() functions to
take a thread instead of a proc for their first argument.
- Add a mutex to protect the system-wide Linux osname, osrelease, and
oss_version variables.
- Change linux_get_prison() to take a thread instead of a proc for its
first argument and to use td_ucred rather than p_ucred. This is ok
because a thread's prison does not change even though it's ucred might.
- Also, change linux_get_prison() to return a struct prison * instead of
a struct linux_prison * since it returns with the struct prison locked
and this makes it easier to safely unlock the prison when we are done
messing with it.

Back out M_* changes, per decision of the TRB.

Approved by: trb

Remove M_TRYWAIT/M_WAITOK/M_WAIT. Callers should use 0.
Merge M_NOWAIT/M_DONTWAIT into a single flag M_NOWAIT.

sysctl -w -> sysctl

o Introduce pr_mtx into struct prison, providing protection for the
mutable contents of struct prison (hostname, securelevel, refcount,
pr_linux, ...)
o Generally introduce mtx_lock()/mtx_unlock() calls throughout kern/
so as to enforce these protections, in particular, in kern_mib.c
protection sysctl access to the hostname and securelevel, as well as
kern_prot.c access to the securelevel for access control purposes.
o Rewrite linux emulator abstractions for accessing per-jail linux
mib entries (osname, osrelease, osversion) so that they don't return
a pointer to the text in the struct linux_prison, rather, a copy
to an array passed into the calls. Likewise, update linprocfs to
use these primitives.
o Update in_pcb.c to always use prison_getip() rather than directly
accessing struct prison.

Reviewed by: jhb

o Replace reference to 'struct proc' with 'struct thread' in 'struct
sysctl_req', which describes in-progress sysctl requests. This permits
sysctl handlers to have access to the current thread, permitting work
on implementing td->td_ucred, migration of suser() to using struct
thread to derive the appropriate ucred, and allowing struct thread to be
passed down to other code, such as network code where td is not currently
available (and curproc is used).

o Note: netncp and netsmb are not updated to reflect this change, as they
are not currently KSE-adapted.

Reviewed by: julian
Obtained from: TrustedBSD Project

Round of cleanups and enhancements. These include (in random order):

o Introduce private types for use in linux syscalls for two reasons:
1. establish type independence for ease in porting and,
2. provide a visual queue as to which syscalls have proper
prototypes to further cleanup the i386/alpha split.
Linuxulator types are prefixed by 'l_'. void and char have not
been "virtualized".

o Provide dummy functions for all syscalls and remove dummy functions
or implementations of truely obsolete syscalls.

o Sanitize the shm*, sem* and msg* syscalls.

o Make a first attempt to implement the linux_sysctl syscall. At this
time it only returns one MIB (KERN_VERSION), but most importantly,
it tells us when we need to add additional sysctls :-)

o Bump the kenel version up to 2.4.2 (this is not the same as the
KERN_VERSION MIB, BTW).

o Implement new syscalls, of which most are specific to i386. Our
syscall table is now up to date with Linux 2.4.2. Some highlights:
- Implement the 32-bit uid_t and gid_t bases syscalls.
- Implement a couple of 64-bit file size/offset bases syscalls.

o Fix or improve numerous syscalls and prototypes.

o Reduce style(9) violations while I'm here. Especially indentation
inconsistencies within the same file are addressed. Re-indenting
did not obfuscate actual changes to the extend that it could not
be combined.

NOTE: I spend some time testing these changes and found that if there
were regressions, they were not caused by these changes AFAICT.
It was observed that installing a RH 7.1 runtime environment
did make matters worse. Hangs and/or reboots have been observed
with and without these changes, so when it failed to make life
better in cases it doesn't look like it made it worse.

Bah, back out part of previous commit. I got too carried away.
linux_debug_map[] is referred to from elsewhere.

Fix warning:
239: warning: no previous prototype for `linux_debug'

o Move per-process jail pointer (p->pr_prison) to inside of the subject
credential structure, ucred (cr->cr_prison).
o Allow jail inheritence to be a function of credential inheritence.
o Abstract prison structure reference counting behind pr_hold() and
pr_free(), invoked by the similarly named credential reference
management functions, removing this code from per-ABI fork/exit code.
o Modify various jail() functions to use struct ucred arguments instead
of struct proc arguments.
o Introduce jailed() function to determine if a credential is jailed,
rather than directly checking pointers all over the place.
o Convert PRISON_CHECK() macro to prison_check() function.
o Move jail() function prototypes to jail.h.
o Emulate the P_JAILED flag in fill_kinfo_proc() and no longer set the
flag in the process flags field itself.
o Eliminate that "const" qualifier from suser/p_can/etc to reflect
mutex use.

Notes:

o Some further cleanup of the linux/jail code is still required.
o It's now possible to consider resolving some of the process vs
credential based permission checking confusion in the socket code.
o Mutex protection of struct prison is still not present, and is
required to protect the reference count plus some fields in the
structure.

Reviewed by: freebsd-arch
Obtained from: TrustedBSD Project

Allow debugging output to be controlled on a per-syscall granularity.
Also clean up debugging output in a slightly more uniform fashion.

The default behavior remains the same (all debugging output is turned on)

Remove call to bzero after MALLOC and instead add M_ZERO
to MALLOC.

Fix typo in license.

Update include directives.

Previous commit changing SYSCTL_HANDLER_ARGS violated KNF.

Pointed out by: bde

Style police catches up with rev 1.26 of src/sys/sys/sysctl.h:

Sanitize SYSCTL_HANDLER_ARGS so that simplistic tools can grog our
sources:

-sysctl_vm_zone SYSCTL_HANDLER_ARGS
+sysctl_vm_zone (SYSCTL_HANDLER_ARGS)

Return Linux kernel version 2.2.12 by default. This is in line
with linux_base-6.1.

$Id$ -> $FreeBSD$

Add sysctl variables for the Linuxulator. These reside under `compat.linux' as
discussed on current.

The following variables are defined (for now):

osname (defaults to "Linux")
Allow users to change the name of the OS as returned by uname(2),
specially added for all those Linux Netscape users and statistics
maniacs :-) We now have what we all wanted!

osrelease (defaults to "2.2.5")
Allow users to change the version of the OS as returned by uname(2).
Since -current supports glibc2.1 now, change the default to 2.2.5
(was 2.0.36).

oss_version (defaults to 198144 [0x030600])
This one will be used by the OSS_GETVERSION ioctl (PR 12917) which I
can commit now that we have the MIB. The default version number is the
lowest version possible with the current 'encoding'.

A note about imprisoned processes (see jail(2)):
These variables are copy-on-write (as suggested by phk). This means that
imprisoned processes will use the system wide value unless it is written/set
by the process. From that moment on, a copy local to the prison will be
used.

A note about the implementation:
I choose to add a single pointer to struct prison, because I didn't like the
idea of changing struct prison every time I come up with a new variable. As
a side effect, the extra storage is only needed when a variable is set from
within the prison. This also minimizes kernel bloat when the Linuxulator is
not used; both compiled in or as a module.

Reviewed by: bde (first version only) and phk