libc: stop trying to create __<syscall> symbols

When we switched to an interposing table (commit 8495e8b1e9e1) for
cancelation points we stopped having concrete implementations of
__<syscall> and in

libc: stop trying to create __<syscall> symbols

When we switched to an interposing table (commit 8495e8b1e9e1) for
cancelation points we stopped having concrete implementations of
__<syscall> and instead use __sys_<syscall> and __thr_<syscall>.
These entries of the form:

__weak_reference(__sys_<syscall>, __<syscall>);

seem to be intended to preserve these symbols, but they have no effect
as __sys_<syscall> isn't defined in the translation units in question.

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D51668

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libc: INTERPOS_SYS macro for interposed syscalls

This macro makes uses the __sys_<foo>_t typedefs from libsys.h to
greatly simplify calling functions in the interposing table.

Reviewed by: kib
Diff

libc: INTERPOS_SYS macro for interposed syscalls

This macro makes uses the __sys_<foo>_t typedefs from libsys.h to
greatly simplify calling functions in the interposing table.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D44389

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lib{c,sys}: return wrapped syscall APIs to libc

These provide standard APIs, but are implemented using another system
call (e.g., pipe implemented in terms of pipe2) or are interposed by the
threadi

lib{c,sys}: return wrapped syscall APIs to libc

These provide standard APIs, but are implemented using another system
call (e.g., pipe implemented in terms of pipe2) or are interposed by the
threading library to support cancelation.

After discussion with kib (see D44111), I've concluded that it is
better to keep most public interfaces in libc with as little
as possible in libsys.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D44241

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libsys: make __libsys_interposing static

Access __libsys_interposing with __libc_interposing_slot() in all
cases to support a move of these wrappers back to libc.

Reviewed by: kib
Differential Revi

libsys: make __libsys_interposing static

Access __libsys_interposing with __libc_interposing_slot() in all
cases to support a move of these wrappers back to libc.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D44239

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libsys: relocate implementations and manpages

Remove core system call implementations and documentation to lib/libsys
and lib/libsys/<arch> from lib/libc/sys and lib/libc/<arch>/<sys>.
Update paths

libsys: relocate implementations and manpages

Remove core system call implementations and documentation to lib/libsys
and lib/libsys/<arch> from lib/libc/sys and lib/libc/<arch>/<sys>.
Update paths to allow libc to find them in their new home.

Reviewed by: kib, emaste, imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/908

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libc: split libc and syscall interposing (1/2)

System calls or their wrappers are now interposed by
__libsys_interposing with purely libc entries remaining in
__libc_interposing.

Use __libsys_inter

libc: split libc and syscall interposing (1/2)

System calls or their wrappers are now interposed by
__libsys_interposing with purely libc entries remaining in
__libc_interposing.

Use __libsys_interposing_slot in libthr to update __libsys_interposing,
but also make __libc_interposing_slot fall back to
__libsys_interposing_slot so an out of date libc has a chance of working
during updates.

Reviewed by: kib, emaste, imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/908

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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

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Remove $FreeBSD$: one-line .c pattern

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

Remove "All Rights Reserved" from FreeBSD Foundation libc copyrights

As per the updated FreeBSD copyright template. These were unambiguous
cases where the Foundation was the only listed copyright h

Remove "All Rights Reserved" from FreeBSD Foundation libc copyrights

As per the updated FreeBSD copyright template. These were unambiguous
cases where the Foundation was the only listed copyright holder.

Sponsored by: The FreeBSD Foundation

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Add missing includes to eliminate -Wmissing-prototypes warnings

Fix known issues which blow up the process after dlopen("libthr.so")
(or loading a dso linked to libthr.so into process which was not
linked against threading library).

- Remove libthr interposers o

Fix known issues which blow up the process after dlopen("libthr.so")
(or loading a dso linked to libthr.so into process which was not
linked against threading library).

- Remove libthr interposers of the libc functions, including
__error(). Instead, functions calls are indirected through the
interposing table, similar to how pthread stubs in libc are already
done. Libc by default points either to syscall trampolines or to
existing libc implementations. On libthr load, libthr rewrites the
pointers to the cancellable implementations already in libthr. The
interposition table is separate from pthreads stubs indirection
table to not pull pthreads stubs into static binaries.

- Postpone the malloc(3) internal mutexes initialization until libthr
is loaded. This avoids recursion between calloc(3) and static
pthread_mutex_t initialization.

- Reinstall signal handlers with wrapper on libthr load. The
_rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2)
when libthr is statically referenced from the main binary.

In the process, fix openat(2), swapcontext(2) and setcontext(2)
interposing. The libc symbols were exported at different versions
than libthr interposers. Export both libc and libthr versions from
libc now, with default set to the higher version from libthr.

Remove unused and disconnected swapcontext(3) userspace implementation
from libc/gen.

No objections from: deischen
Tested by: pho, antoine (exp-run) (previous versions)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

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