libc: allow __cxa_atexit handlers to be added during __cxa_finalize

science/dlib-cpp reveals an interesting scenario that works fine on
other platforms but not on FreeBSD; notably, it ends up creati

libc: allow __cxa_atexit handlers to be added during __cxa_finalize

science/dlib-cpp reveals an interesting scenario that works fine on
other platforms but not on FreeBSD; notably, it ends up creating a new
global object from some destructor which is called during
__cxa_finalize. This breaks when libdlib is dlopen()ed and then
subsequently dlclose()ed, as we never end up invoking the created
object's dtor until program exit when the shlib is already unmapped.

Fix it by noting when we're in the middle of __cxa_finalize for a dso,
and then restarting the search if __cxa_atexit() was called in the
middle somewhere.

We wait until we've processed the initial set before starting over and
processing the newly added handlers as if it were a complete set of
handlers added during runtime. The alternative is calling them as
they're added to maintain a LIFO in terms of total ordering, but in
theory a constructor could add another global object that also needs to
be destroyed, and that object needs to be destroyed after the one that
constructed it to avoid creating unexpected lifetime issues.

This manifests in the pdlib PHP extension for dlib crashing, see [0].

[0] https://github.com/goodspb/pdlib/issues/39

PR: 285870
Reviewed by: kevans (also supplied commit message)
MFC after: 1 week

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lib: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl s

lib: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

show more ...

libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Kee

libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Keep those.

Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D42385

show more ...

Remove $FreeBSD$: one-line .c pattern

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

MFHead @347527

Sponsored by: The FreeBSD Foundation

Fix order of destructors between main binary and libraries.

Since inits for the main binary are run from rtld (for some time), the
rtld_exit atexit(3) handler, which is passed from rtld to the progr

Fix order of destructors between main binary and libraries.

Since inits for the main binary are run from rtld (for some time), the
rtld_exit atexit(3) handler, which is passed from rtld to the program
entry and installed by csu, is installed after any atexit(3) handlers
installed by main binary constructors. This means that rtld_exit() is
fired before main binary handlers.

Typical C++ static constructors are executed from init (either binary
or libs) but use atexit(3) to ensure that destructors are called in
the right order, independent of the linking order. Also, C++
libraries finalizers call __cxa_finalize(3) to flush library'
atexit(3) entries. Since atexit(3) entry is cleared after being run,
this would be mostly innocent, except that, atexit(rtld_exit) done
after main binary constructors, makes destructors from libraries
executed before destructors for main.

Fix by reordering atexit(rtld_exit) before inits for main binary, same
as it happened when inits were called by csu. Do it using new private
libc symbol with pre-defined ABI.

Reported. tested, and reviewed by: kan
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

show more ...

libc: allow __cxa_atexit handlers to be added during __cxa_finalize

science/dlib-cpp reveals an interesting scenario that works fine on
other platforms but not on FreeBSD; notably, it ends up creati

libc: allow __cxa_atexit handlers to be added during __cxa_finalize

science/dlib-cpp reveals an interesting scenario that works fine on
other platforms but not on FreeBSD; notably, it ends up creating a new
global object from some destructor which is called during
__cxa_finalize. This breaks when libdlib is dlopen()ed and then
subsequently dlclose()ed, as we never end up invoking the created
object's dtor until program exit when the shlib is already unmapped.

Fix it by noting when we're in the middle of __cxa_finalize for a dso,
and then restarting the search if __cxa_atexit() was called in the
middle somewhere.

We wait until we've processed the initial set before starting over and
processing the newly added handlers as if it were a complete set of
handlers added during runtime. The alternative is calling them as
they're added to maintain a LIFO in terms of total ordering, but in
theory a constructor could add another global object that also needs to
be destroyed, and that object needs to be destroyed after the one that
constructed it to avoid creating unexpected lifetime issues.

This manifests in the pdlib PHP extension for dlib crashing, see [0].

[0] https://github.com/goodspb/pdlib/issues/39

PR: 285870
Reviewed by: kevans (also supplied commit message)
MFC after: 1 week

show more ...

lib: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl s

lib: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

show more ...

libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Kee

libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Keep those.

Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D42385

show more ...

Remove $FreeBSD$: one-line .c pattern

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

MFHead @347527

Sponsored by: The FreeBSD Foundation

Fix order of destructors between main binary and libraries.

Since inits for the main binary are run from rtld (for some time), the
rtld_exit atexit(3) handler, which is passed from rtld to the progr

Fix order of destructors between main binary and libraries.

Since inits for the main binary are run from rtld (for some time), the
rtld_exit atexit(3) handler, which is passed from rtld to the program
entry and installed by csu, is installed after any atexit(3) handlers
installed by main binary constructors. This means that rtld_exit() is
fired before main binary handlers.

Typical C++ static constructors are executed from init (either binary
or libs) but use atexit(3) to ensure that destructors are called in
the right order, independent of the linking order. Also, C++
libraries finalizers call __cxa_finalize(3) to flush library'
atexit(3) entries. Since atexit(3) entry is cleared after being run,
this would be mostly innocent, except that, atexit(rtld_exit) done
after main binary constructors, makes destructors from libraries
executed before destructors for main.

Fix by reordering atexit(rtld_exit) before inits for main binary, same
as it happened when inits were called by csu. Do it using new private
libc symbol with pre-defined ABI.

Reported. tested, and reviewed by: kan
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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Merge ^/head r325999 through r326131.

General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier f

General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

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Merge from head

Sponsored by: Gandi.net

Merge from head

Merge from head

Sync up with head (up to r288341).

Merge ^/head r287878 through r288034.

Remove names from prototypes

Add declarations to eliminate -Wmissing-prototypes warnings.

MFC @ r266724

An SVM update will follow this.

Merge head

IFC @264767

Silence a warning with GCC that was breaking the build with Juniper's GCC.

Reviewed by: marcel