Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r265255, r270506:
Allow "a.out" as an alias for the executable if no other matching entries
are found.

MFC r269750:

In r268463, I misplaced a return in demangle(), causing the function to
erroneously skip symbols that were not mangled at all. Fix this by
moving the return into the preceding if block.

While here, simplify the code by letting __cxa_demangle() allocate the
needed space for the demangled symbol. This also fixes a memory leak,
which would occur whenever __cxa_demangle() failed.

Reported by: pgj
PR: base/191981

MFC r268463:

In libproc, avoid calling __cxa_demangle(), and thus depending on either
libcxxrt or libsupc++, if WITHOUT_CXX is defined. [1]

Noticed by: sbruno

[1] However, on stable/10 this is more accurately described by
WITHOUT_GNUCXX, so I've changed the test to that instead.

MFC r264436:
Fix some off-by-one errors. The kve_end and rdl_eaddr fields contain the
first address after the end of the map entry and should therefore be
excluded.

MFC r258000:
Consistently add the relocation offset only when the ELF type is not
ET_EXEC. This fixes several problems with the DTrace pid provider not
being able to match probes.

MFC r257300:
Fix an off-by-one error when checking whether a given address is within
the extent of a symbol.

MFC r256661 r257222 r257235 r257248 r257298.

MFC r256661:
Fix the libproc build when DEBUG is defined.

MFC r257222:
Clean up the debug printing in libproc a bit. In particular:

* Don't print any error messages to stderr unless DEBUG is defined.
* Add a DPRINTFX macro for use when errno isn't set.
* Print the error string from libelf when appropriate.

MFC r257235:
Remove an incorrect debug printf.

MFC r257248:
Fix the build with gcc.

MFC r257298:
Revert r257248 and fix the problem in a way that doesn't violate style(9).

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Fix the return value when we found a symbol in .dynstr. This nasty bug was
preventing a lot of symbol lookups in dtruss -s, for example.

When calling the C++ demangler, make sure to free the returned buffer,
which might have been reallocated.

Pointed out by: stefanf

Add support for demangling C++ symbols. This requires linking libproc with
libc++rt/libsupc++.

Discussed with: theraven

Make sure we visit both symbol sections even if one of them doesn't
exist. This makes it possible to dtrace some C++ programs like devd.

Several fixes for libproc:
o return the correct status in proc_wstatus()
o proc_read takes a void *
o correctly allocate the objs structure array

Sponsored by: The FreeBSD Foundation

New version of libproc. Changes are:
* breakpoint setup support
* register query
* symbol to address mapping and vice-versa
* more misc utility functions based on their Solaris counterpart

Also, I've written some test cases.

Sponsored by: The FreeBSD Foundation

Add a process library with some stubs that the DTrace client needs.
These will be fleshed out as part of the DTrace userland tracing
development.

For now, the kernel tracing part of DTrace requires minimal functionality
for this library.

The API for this library is deliberately different from the libproc in
OpenSolaris due to licensing restrictions.