linux_pwd_onexec: do not abort image activation if emul path does not exist

Instead clear the altroot, if any.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D43833

linux(4): Follow style(9), don't include both sys/param.h and sys/types.h

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

linux(4): Uniformly dev_t arguments translation

The two main uses of dev_t are in struct stat and as a parameter of the
mknod system calls.
As of version 2.6.0 of the Linux kernel, dev_t is a 32-bit quantity
with 12 bits set asaid for the major number and 20 for the minor number.
The in-kernel dev_t encoded as MMMmmmmm, where M is a hex digit of the
major number and m is a hex digit of the minor number.
The user-space dev_t encoded as mmmM MMmm, where M and m is the major
and minor numbers accordingly. This is downward compatible with legacy
systems where dev_t is 16 bits wide, encoded as MMmm.
In glibc dev_t is a 64-bit quantity, with 32-bit major and minor numbers,
encoded as MMMM Mmmm mmmM MMmm. This is downward compatible with the Linux
kernel and with legacy systems where dev_t is 16 bits wide.
In the FreeBSD dev_t is a 64-bit quantity. The major and minor numbers
are encoded as MMMmmmMm, therefore conversion of the device numbers between
Linux user-space and FreeBSD kernel required.

linux(4): Move translate_vnhook_major_minor() into the Linux common module

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(4): Move use_real_names knob to the linux.c

MI linux.[c|h] are the module independent in terms of the Linux emulation
layer (ie, intended for both ISA - 32 & 64 bit), analogue of MD linux.h.
There must be a code here that cannot be placed into the corresponding by
common sense MI source and header files, i.e., code is machine independent,
but ISA dependent.
For the use_real_names knob, the code must be placed into the
linux_socket.[c|h], however linux_socket is ISA dependent.

MFC after: 2 weeks

Adjust linux_get_char_devices() definition to avoid clang 15 warning

With clang 15, the following -Werror warning is produced:

sys/compat/linux/linux_util.c:243:23: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
linux_get_char_devices()
^
void

This is because linux_get_char_devices() is declared with a (void)
argument list, but defined with an empty argument list. Make the
definition match the declaration.

MFC after: 3 days

linux: add sysctl to pass untranslated interface names

Reviewed by: kib
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D33792

vfs: drop the always curthread argument from kern_alternate_path

linux: remove the always curthread argument from lconvpath

linux(4): Eliminate unused includes.

MFC after: 2 weeks

linux(4): Reimplement futexes using umtx.

Differential Revision: https://reviews.freebsd.org/D31236
MFC after: 2 weeks

Move V4L feature declarations and DTrace provider definitions from
linux_common.c to linux_util.c so they become available on i386.

linux_common.c defines the linux_common kernel module but this module does
not exist on i386 and linux_common.c is not included in the linux module.
linux_util.c is included in the linux_common module on amd64 and the linux
module on i386.

Remove linux_common.c from files.i386 again. It was added recently in
r367433 when the DTrace provider definitions were moved.

The V4L feature declarations were moved to linux_common in r283423.

- 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

Fix potential race condition in linux stat(2).

Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D25618

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

Add compat.linux.emul_path, so it can be set to something other
than "/compat/linux". Useful when you have several compat directories
with different Linux versions and you don't want to clash with files
installed by linux-c7 packages.

Reviewed by: bcr (manpages)
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22574

Move most of the contents of opt_compat.h to opt_global.h.

opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.

Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.

Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.

Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941

Linuxulator: apply style(9) to return

Sponsored by: Turing Robotic Industries Inc.

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.

Add special handling for current in-tree drm devices, like r323692 added
for drm-next.

Use sizeof instead of strlen on string constants. The compiler doesn't
optimise the strlen calls away with -ffreestanding.

linsysfs(5): Add support for recent libdrm

Expose more information about PCI devices (and GPUs in particular) via
linsysfs to libdrm.

This allows unmodified modern 64-bit Linux libdrm to work, which allows
modern Linux Mesa to work. The submitter reports that he tested the change
with an Ubuntu 16.04 chroot + amdgpu from graphics/drm-next-kmod.

PR: 222375
Submitted by: Greg V <greg AT unrelenting.technology>

Implement epoll family system calls. This is a tiny wrapper
around kqueue() to implement epoll subset of functionality.
The kqueue user data are 32bit on i386 which is not enough for
epoll user data, so we keep user data in the proc emuldata.

Initial patch developed by rdivacky@ in 2007, then extended
by Yuri Victorovich @ r255672 and finished by me
in collaboration with mjg@ and jillies@.

Differential Revision: https://reviews.freebsd.org/D1092

Where possible we will use M_LINUX malloc(9) type.
Move M_FUTEX defines to the linux_common.ko.

Differential Revision: https://reviews.freebsd.org/D1077
Reviewed by: emaste

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

- 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

- >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).

Remove direct access to si_name.

Code should just use the devtoname() function to obtain the name of a
character device. Also add const keywords to pieces of code that need it
to build properly.

MFC after: 2 weeks

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

Retire the MALLOC and FREE macros. They are an abomination unto style(9).

MFC after: 3 months

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

Push down the major/minor conversion for pts/%u to improve consistency.

In the mpsafetty branch, Linux sshd seems to work properly inside a
jail. Some small modifications had to be made to the Linux compatibility
layer.

The Linux PTY routines always expect the device major number to be 136
or higher. Our code always set the major/minor number pair to 136:0.
This makes routines like ttyname() and ptsname() fail, because we'll end
up having ambiguous device numbers.

The conversion was not performed on all *stat() routines, which meant in
some cases the numbers didn't get transformed. By pushing the conversion
into linux_driver_get_major_minor(), the transformation will take place
on all calls.

Approved by: philip (mentor), rdivacky

Implement the linux syscalls
openat, mkdirat, mknodat, fchownat, futimesat, fstatat, unlinkat,
renameat, linkat, symlinkat, readlinkat, fchmodat, faccessat.

Submitted by: rdivacky
Sponsored by: Google Summer of Code 2007
Tested by: pho

Add the support for the AT_FDCWD and fd-relative name lookups to the
namei(9).

Based on the submission by rdivacky,
sponsored by Google Summer of Code 2007
Reviewed by: rwatson, rdivacky
Tested by: pho

Partial MFp4 of 114977:
Whitespace commit: Fix grammar, spelling and punctuation.

Submitted by: "Scot Hetzel" <swhetzel@gmail.com>

Add the linux 2.6.x stuff (not used by default!):
- TLS - complete
- pid/tid mangling - complete
- thread area - complete
- futexes - complete with issues
- clone() extension - complete with some possible minor issues
- mq*/timer*/clock* stuff - complete but untested and the mq* stuff is
disabled when not build as part of the kernel with native FreeBSD mq*
support (module support for this will come later)

Tested with:
- linux-firefox - works, tested
- linux-opera - works, tested
- linux-realplay - doesnt work, issue with futexes
- linux-skype - doesnt work, issue with futexes
- linux-rt2-demo - works, tested
- linux-acroread - doesnt work, unknown reason (coredump) and sometimes
issue with futexes
- various unix utilities in linux-base-gentoo3 and linux-base-fc4:
everything tried worked

On amd64 not everything is supported like on i386, the catchup is planned for
later when the remaining bugs in the new functions are fixed.

To test this new stuff, you have to run
sysctl compat.linux.osrelease=2.6.16
to switch back use
sysctl compat.linux.osrelease=2.4.2

Don't switch while running a linux program, strange things may or may not
happen.

Sponsored by: Google SoC 2006
Submitted by: rdivacky
Some suggestions/help by: jhb, kib, manu@NetBSD.org, netchild

Enhance the Linux emulation layer to make MegaRAID SAS managements tool happy.
Add back in a scheme to emulate old type major/minor numbers via hooks into
stat, linprocfs to return major/minors that Linux app's expect. Currently
only /dev/null is always registered. Drivers can register via the Linux
type shim similar to the ioctl shim but by using
linux_device_register_handler/linux_device_unregister_handler functions.
The structure is:

struct linux_device_handler {
char *bsd_driver_name;
char *linux_driver_name;
char *bsd_device_name;
char *linux_device_name;
int linux_major;
int linux_minor;
int linux_char_device;
};

Linprocfs uses this to display the major number of the driver. The
soon to be available linsysfs will use it to fill in the driver name.
Linux_stat uses it to translate the major/minor into Linux type values.

Note major numbers are dynamically assigned via passing in a -1 for
the major number so we don't need to keep track of them.

This is somewhat needed due to us switching to our devfs. MegaCli
will not run until I add in the linsysfs and mfi Linux compat changes.

Sponsored by: IronPort Systems

Remove linux_emul_find() and the CHECKALT*() macros as they are no longer
used.

Make linux_emul_convpath() a simple wrapper for kern_alternate_path().

Start each of the license/copyright comments with /*-

Include <sys/mutex.h> and its prerequisite <sys/lock.h> instead of
depending on namespace pollution in <sys/vnode.h> for the definition
of GIANT_REQUIRED.

Sorted includes.

Mark linux_emul_convpath() as GIANT_REQUIRED.

VOP_GETATTR() wants the vnode passed to it to be locked. Instead
of adding the code to lock and unlock the vnodes and taking care
to avoid deadlock, simplify linux_emul_convpath() by comparing the
vnode pointers directly instead of comparing their va_fsid and
va_fileid attributes. This allows the removal of the calls to
VOP_GETATTR().

Use __FBSDID().

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.

Add function linux_msg() for regulating output from the linux emulation
code, make the emulator use it.

Rename unsupported_msg() to unimplemented_syscall(). Rename some arguments
for clarity

Fixup grammar.

Requested by: bde

Add a new function linux_emul_convpath(), which is a version of
linux_emul_find() that does not use stack gap storage but instead
always returns the resulting path in a malloc'd kernel buffer.
Implement linux_emul_find() in terms of this function. Also add
LCONVPATH* macros that wrap linux_emul_convpath in the same way
that the CHECKALT* macros wrap linux_emul_find().

Simple p_ucred -> td_ucred changes to start using the per-thread ucred
reference.

Eliminate the prefix parameter to linux_emul_find(), which was always
linux_emul_path anyway. Linux_emul_find() has interesting bugs in its
prefix handling (which luckily are not currently exploitable); this
commit is preliminary to an attempt at cleaning it up.

Approved by: marcel

KSE Milestone 2
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after: ha ha ha ha

Fix typo: seperate -> separate.

Seperate does not exist in the english language.

Back out proc locking to protect p_ucred for obtaining additional
references along with the actual obtaining of additional references.

Lock access to proc members.

Glanced over by: marcel

Update include directives.

Add bounds checking to stackgap_alloc. Previously it was possible
to construct a path that was long enough (ie longer than
SPARE_USRSPACE bytes) and trash the stack.

Note that SPARE_USRSPACE is much smaller than MAXPATHLEN so that
the Linuxulator will now return ENAMETOOLONG even if the path
is smaller than MAXPATHLEN.

PR: 12749

Remove unneeded #include <vm/vm_zone.h>

Generated by: src/tools/tools/kerninclude

Introduce NDFREE (and remove VOP_ABORTOP)

$Id$ -> $FreeBSD$

Removed unused #includes.

Don't include <sys/ioctl.h> in the kernel. Stage 1: don't include
it when it is not used. In most cases, the reasons for including it
went away when the special ioctl headers became self-sufficient.

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Changed type of ni_dirp in `struct namei' from caddr_t to `const char *'
so that the compiler can see that it is OK to use const strings in
NDINIT(). Some emulators want to use paths of the form "/compat/foo".
Removed the casts that hid the non-problem. Didn't fix the missing
consts in syscalls.master that hid the non-problem.

Fix memory leak bug in the path parsing code which never released it's
buffer in certain error conditions. Sync up the code to that in NetBSD
where applicable.

Reviewed by: Gary Jennejohn <garyj@munich.netsurf.de>
Submitted by: Michael Smith <msmith@atrad.adelaide.edu.au>
Obtained from: NetBSD sources

Mega-commit for Linux emulator update.. This has been stress tested under
netscape-2.0 for Linux running all the Java stuff. The scrollbars are now
working, at least on my machine. (whew! :-)

I'm uncomfortable with the size of this commit, but it's too
inter-dependant to easily seperate out.

The main changes:

COMPAT_LINUX is *GONE*. Most of the code has been moved out of the i386
machine dependent section into the linux emulator itself. The int 0x80
syscall code was almost identical to the lcall 7,0 code and a minor tweak
allows them to both be used with the same C code. All kernels can now
just modload the lkm and it'll DTRT without having to rebuild the kernel
first. Like IBCS2, you can statically compile it in with "options LINUX".

A pile of new syscalls implemented, including getdents(), llseek(),
readv(), writev(), msync(), personality(). The Linux-ELF libraries want
to use some of these.

linux_select() now obeys Linux semantics, ie: returns the time remaining
of the timeout value rather than leaving it the original value.

Quite a few bugs removed, including incorrect arguments being used in
syscalls.. eg: mixups between passing the sigset as an int, vs passing
it as a pointer and doing a copyin(), missing return values, unhandled
cases, SIOC* ioctls, etc.

The build for the code has changed. i386/conf/files now knows how
to build linux_genassym and generate linux_assym.h on the fly.

Supporting changes elsewhere in the kernel:

The user-mode signal trampoline has moved from the U area to immediately
below the top of the stack (below PS_STRINGS). This allows the different
binary emulations to have their own signal trampoline code (which gets rid
of the hardwired syscall 103 (sigreturn on BSD, syslog on Linux)) and so
that the emulator can provide the exact "struct sigcontext *" argument to
the program's signal handlers.

The sigstack's "ss_flags" now uses SS_DISABLE and SS_ONSTACK flags, which
have the same values as the re-used SA_DISABLE and SA_ONSTACK which are
intended for sigaction only. This enables the support of a SA_RESETHAND
flag to sigaction to implement the gross SYSV and Linux SA_ONESHOT signal
semantics where the signal handler is reset when it's triggered.

makesyscalls.sh no longer appends the struct sysentvec on the end of the
generated init_sysent.c code. It's a lot saner to have it in a seperate
file rather than trying to update the structure inside the awk script. :-)

At exec time, the dozen bytes or so of signal trampoline code are copied
to the top of the user's stack, rather than obtaining the trampoline code
the old way by getting a clone of the parent's user area. This allows
Linux and native binaries to freely exec each other without getting
trampolines mixed up.