dtrace: remove dead code for PR_REQUESTED

libproc's PR_REQUESTED is not implemented on FreeBSD. Remove dead code
in dtrace that would handle it.

Reviewed by: markj
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D41225

dtrace: do not overload libproc flags

dtrace stored its PR_RLC and PR_KLC flags in the proc_handle's flags,
where they collided with PATTACH_FORCE and PATTACH_RDONLY, respectively.
Thus, Psetflags(PR_KLC) effectively also set the PATTACH_RDONLY flag.

Since the flags are private to dtrace (at least on FreeBSD), store them in
dtrace's own dt_proc structure instead.

On FreeBSD, either PR_RLC or PR_KLC was always set, so remove code that
would handle the case where neither was set.

Reviewed by: markj
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D41121

dtrace: remove illumos code from dt_proc.c

The illumos #ifdef's in this file make it harder to read and maintain.
There is little change upstream, and increasing changes for FreeBSD.
Remove the illumos code with `unifdef`. The only manual changes here
are the #includes and #defines at the top, and removing blank lines.

Reviewed by: markj
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D41173

dtrace: prevent forked child from running after an error condition

The pid/killonerror test uses an invalid probe specifier to verify that
the child process is killed. It occasionally fails because the "date"
command is allowed to run long enough to print the date. This is harmless
in this case, but is clearly not ideal.

When the dt_proc_control thread is about to exit, and the dtrace command
forked the child, do not make the child runnable.

Reviewed by: markj
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D40976

Complete support for dtrace's -x setenv option.

This allows one to override the environment for processes created with
dtrace -c. By default, the environment is inherited.

This support was originally merged from illumos in r249367 but was lost
when the commit was later reverted and then brought back piecemeal.

Reported by: Samuel Lepetit <slepetit@apple.com>
MFC after: 2 weeks

Add an envp argument to proc_create().

This is needed to support dtrace's -x setenv option.

MFC after: 2 weeks

libdtrace: replace "DOODAD" with more descriptive string

Previously some unimplemented libdtrace routines printed the function,
file and line number, followed by "DOODAD." That is not particularly
informative, so replace it with a message reporting the actual issue.

Sponsored by: The FreeBSD Foundation

Mechanically convert cddl sun #ifdef's to illumos

Since the upstream for cddl code is now illumos not sun, mechanically
convert all sun #ifdef's to illumos #ifdef's which have been used in all
newer code for some time.

Also do a manual pass to correct the use if #ifdef comments as per style(9)
as well as few uses of #if defined(__FreeBSD__) vs #ifndef illumos.

MFC after: 1 month
Sponsored by: Multiplay

DTrace: Revert r249367

The following change from illumos brought caused DTrace to
pause in an interactive environment:

3026 libdtrace should set LD_NOLAZYLOAD=1 to help the pid provider

This was not detected during testing because it doesn't
affect scripts.

We shouldn't be changing the environment, especially since the
LD_NOLAZYLOAD option doesn't apply to our (GNU) ld.
Unfortunately the change from upstream was made in such a way
that it is very difficult to separate this change from the
others so, at least for now, it's better to just revert
everything.

Reference:
https://www.illumos.org/issues/3026

Reported by: Navdeep Parhar and Mark Johnston

When we return with an error we cannot unlock the mutex, because
it's been freed. Protect against that, hopefully unlikely, case.

Reviewed by: rpaulo
MFC after: 2 weeks

Change SIGUSR1 to SIGTHR to properly wake up a process that is being
traced. The use of SIGUSR1 caused traced processes (those attached to
with dtrace -p) to exit when dtrace exited.

MFC in: 1 week

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

Add libdtrace support for tracing userland programs.

Summary of changes:
* Implement a compatibility shim between Solaris libproc and our
libproc and remove several ifdefs because of this.
* Port the drti to FreeBSD.
* Implement the missing DOODAD sections
* Link with libproc and librtld_db
* Support for ustack, jstack and uregs (by sson@)
* Misc bugfixing

When writing the SUWN_dof section, we had to resort to building the ELF
file layout by "hand". This is the job of libelf, but our libelf doesn't
support this yet. When libelf is fixed, we can remove the code under
#ifdef BROKEN_LIBELF.

Sponsored by: The FreeBSD Foundation

Fix the result of a mismerge. MUTEX_HELD should be DT_MUTEX_HELD() and
Plmid() is not supposed to be called.

proc_wait() was replaced by proc_wstatus(). Right now this call is
useless because userland support is not working on HEAD, but this makes
libdtrace compile again.

Sponsored by: The FreeBSD Foundation

Update to the new proc_detach() function.

Sponsored by: The FreeBSD Foundation

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

Merge latest DTrace changes from Perforce.

Approved by: jb

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

* Use FreeBSD's process library instead of the Solaris one.
* There are a few placeholders in here for which there isn't libproc
support code yet. This is relevent to userland tracing. This set of
commits is designed to get kernel tracing up and running, with the
userland stuff to follow later.