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

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

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

Convert remaining cap_rights_init users to cap_rights_init_one

semantic patch:

@@

expression rights, r;

@@

- cap_rights_init(&rights, r)
+ cap_rights_init_one(&rights, r)

cache: drop the always curthread argument from reverse lookup routines

Note VOP_VPTOCNP keeps getting it as temporary compatibility for zfs.

Tested by: pho

Remove unused argument to priv_check_cred.

Patch mostly generated with cocinnelle:

@@
expression E1,E2;
@@

- priv_check_cred(E1,E2,0)
+ priv_check_cred(E1,E2)

Sponsored by: The FreeBSD Foundation

Add const to input-only char * arguments.

These arguments are mostly paths handled by NAMEI*() macros which already
take const char * arguments.

This change improves the match between syscalls.master and the public
declerations of system calls.

Reviewed by: kib (prior version)
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D17812

Fix some filemon path logging issues.

- Properly handle snprintf return value for truncation and avoid
overflowing the later write with the bogus length.
- Increase the msgbufr size to handle a rename of 2 full files.

The larger allocation causes a slight performance hit which will be mitigated
in the future. A rewrite with sbufs will likely be done as well.

Reported by: Ilja Van Sprundel <ivansprundel@ioactive.com>
MFC after: 2 weeks
Approved by: so (gtetlow)
Reviewed by: kib
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D16098

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

sys/dev: 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.

Cleanup COMPAT_FREEBSD32 support.

This is a NOP.

The COMPAT_IA32 was renamed in r205014 to COMPAT_FREEBSD32 and
COMPAT_ARCH32 does not seem to have existed. Also remove some
leftovers from the sysent rework in r301404. Include
freebsd32_util.h for the freebsd32_sysent prototype.

X-MFC-With: r301404
Reported by: kib
MFC after: 3 days
Sponsored by: EMC / Isilon Storage Division

Fix build after r301404.

X-MFC-With: r301404
MFC after: 1 week

Support all architectures by just using sysent.

PowerPC64 has two different ABIs, neither of which is elf64_freebsd_sysvec.
Using sysent and freebsd32_sysent achieves the same effect.

X-MFC-With: r301130
MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

Don't truncate existing error when writing the log.

Suggested by: markj
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Write to the log using the tracer's credentials.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

exec: Cease tracing if credentials will change with the new image.

This also prevents tracing to a P_INEXEC process since it could race
with other processes attaching to it in filemon_event_process_exec() due
to the filemon_get_proc() race of incrementing ref and then locking the
filemon. With the no-P_INEXEC invariant in place the p_filemon may only
be the same or NULL when trying to drop it in
filemon_event_process_exec().

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D6545

filemon exec: Use imgp->execpath rather than vn_fullpath(9).

This will be more accurate as the actual name is provided if ran
from an absolute path in do_execve().

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Handle copyin failures.

Skip the log entry as there is nothing good to write out. Don't fail
the syscall though since it already succeeded. There's no reason
filemon's tracing failure should fail the already-succeeded syscall.

Record the error for later to return from close(2) on the filemon devfs
file descriptor.

Discussed with: markj, sjg, kib (briefly with kib)
Reported by: mjg
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Remove unused done argument to copyinstr(9).

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Return any log write failure encountered when closing the filemon fd.

Discussed with: sjg, markj
Reviewed by: sjg
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Consolidate common link(2) logic.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Attempt to use the namecache for openat(2) path resolution.

This finishes the work done in D2810.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Use curthread for vn_fullpath.

No functional change.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Consolidate open(2) and openat(2) code.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Stop tracking stat(2).

None of lstat(2), fstat(2), fstatat(2) were tracked either.

The other filemon implementations also do not track stat(2), nor
does bmake utilize it. The act of opening a file for read should
be enough to decide that a file is a dependency. There could be
rare cases where just having a file would cause a dependency but it
is unlikely.

MFC after: 2 weeks
Also noted by: sjg
Sponsored by: EMC / Isilon Storage Division

Track filemon usage via a proc.p_filemon pointer rather than its own lists.

- proc.p_filemon is added which is protected by PROC_LOCK. This improves
performance and avoids double-fork issues, taking allproc_lock
while in syscalls, and walking the process tree in syscalls. A
particular proc.p_filemon can only be changed to NULL or another
filemon, or the filemon inherited, while the filemon->lock is held.
- Filemon are reference counted. On the last reference the log will be closed.
- When closing the devfs file handle, the filemon will be detached from all
processes and inheritance prevented.
- Disallow attaching to a process already being traced since filemon is
typically intended to be used on children only. This is allowed for
curproc as bmake relies on this behavior for rare cases when combining
.MAKE with .META.
- Detach any previously tracked process on ioctl(FILEMON_SET_PID).
- Handle error from devfs_set_cdevpriv() in filemon_open().
- The global filemon lock and lists are removed.
- A free list is no longer kept. Previously this list was
forever-expanding and never garbage cleaned.
- No longer loses track of double-forks. If the process holding the filemon
handle closes it will close the log rather than wait on a daemonized process,
but it will log all activity until it closes its handle. The filemon
will be removed from the process and not inherited.
- A separate process count is kept only as an optimization for
forced detachment to avoid taking allproc_lock and walking the entire
process tree.
- struct filemon access is protected by sx(9) filemon->lock as it was before.
- Add more comments and KASSERTS.

MFC after: 2 weeks
Reviewed by: kib, mjg, markj (all on previous versions)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D5520

Only call bwillwrite() for logging to vnodes, as other fo_write() calls do.

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

Remove filemon->lock wrappers.

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

Remove old compatibility checks.

MFC after: 3 days
Sponsored by: EMC / Isilon Storage Division

Filemon: Fix panic when fork1() is called from kproc_create().

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

filemon: Track the process pointer rather than a pid.

The process is not held since the process_exit hook is called after the
exithold. There is no need to hold the process since the hook will
always see it exiting via the process_exit event.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

filemon: Use process_exec EVENTHANDLER to capture sys_execve.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Follow-up r294967: Mark flags unused.

X-MFC-With: r294967
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

filemon: Trace fork via process_fork event.

This avoids needing ugly hooks and needing both a vfork and fork
handler.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

filemon: Use process_exit EVENTHANDLER to capture process exit.

This fixes some cases where a process could exit without being untracked
by filemon.

Reported by: mjg
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

filemon_comment has nothing to do with wrappers so move it out of filemon_wrapper.c.

It only prints the header from filemon_ioctl. Keep the name though to stay
closer to other implementations.

MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

filemon_ioctl: Lock the associated filemon handle before writing to it.

Reported by: mjg
MFC after: 2 weeks
Sponsored by: EMC / Isilon Storage Division

Avoid taking proctree_lock and searching parents in wrappers if not needed.

This should help the case where filemon is loaded but not in use.

Sponsored by: EMC / Isilon Storage Division
MFC after: 2 weeks

Remove unneeded inuse list locking in filemon_comment().

Sponsored by: EMC / Isilon Storage Division
MFC after: 2 weeks

Move common locking for filemon_inuse and struct filemon* to filemon_pid_check().

This keeps the lock for the filemon_inuse list held only while reading
the list.

Sponsored by: EMC / Isilon Storage Division
MFC after: 2 weeks

sx_sunlock for sx_slock

filemon_pid_check needs to hold proctree_lock

Reviewed by: kib
MFC after: few days

Latest clang uses openat(2).

If the pathname is absolute or dirfd is AT_FDCWD we can
handle it exactly like open(2).
Otherwise we output an A record to indicate that the path of
an open directory needs to be used (earlier in the trace).

Differential Revision: D2810
Reviewed by: jhb
MFC after: a bit

- Use pget(PGET_CANDEBUG | PGET_NOTWEXIT) to determine if the specified
PID is valid for monitoring in FILEMON_SET_PID ioctl.

- Set the monitored PID to -1 when the process exits.

Suggested by: jilles
Tested by: sjg
MFC after: 3 days

Match the options of the kernel.

Iterate rather than use recursion. We can blow out the kernel stack if there
is a long chain of fork(2)s.

There's no need to make filemon specific to i386 and amd64. All
LP64 architectures define elf64_freebsd_sysvec and all ILP32
architectures define elf32_freebsd_sysvec.

Add the 'filemon' device. 'filemon' is a kernel module that provides a device
interface for processes to record system calls of its children.

Submitted by: Juniper Networks.