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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Revert "lib{c,sys}: normalize export of openat, setcontext, and swapcontext"

I put the symbols in the wrong file (should have been
lib/libc/sys/Symbol.map), added a duplicate pdfork entry due to a b

Revert "lib{c,sys}: normalize export of openat, setcontext, and swapcontext"

I put the symbols in the wrong file (should have been
lib/libc/sys/Symbol.map), added a duplicate pdfork entry due to a botch
rebase, and there seems to be a issue with gcc13/binutils not exposing
the symbols so revert the whole thing while I debug.

This reverts commit ee632fb9eb4a060a4087a7f5425bfe36e65cda61.

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lib{c,sys}: normalize export of openat, setcontext, and swapcontext

List them in the symbol map rather than using the __sym_default to
expose them. This will allow later improvements in the stub
im

lib{c,sys}: normalize export of openat, setcontext, and swapcontext

List them in the symbol map rather than using the __sym_default to
expose them. This will allow later improvements in the stub
implementations in libc.so.

Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D44113

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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/

libc: partially revert r326576

In r326576 ("use @@@ instead of @@ in __sym_default"), an earlier version of
the phabricator-discussed patch was inadvertently committed. The commit
message claims th

libc: partially revert r326576

In r326576 ("use @@@ instead of @@ in __sym_default"), an earlier version of
the phabricator-discussed patch was inadvertently committed. The commit
message claims that @@@ means that weak is not needed, but that was due to a
misunderstanding of the use of weak symbols in this context by the submitted
in the first draft of the patch; the description text was not updated to
match the discussion. As discussed in phabricator, weak is needed for
symbol interposing because of the behavior of our rtld, and is widely used
elsewhere in libc.

This partial revert restores the approved version of the patch and permits
symbol interposing for openat.

Reported by: Raymond Ramsden <rramsden AT isilon.com>
Reviewed by: dim, emaste, kib (2017)
Discussed with: kib (2020)
Differential Revision: https://reviews.freebsd.org/D11653

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use @@@ instead of @@ in __sym_default

Using
.symver foo,foo@@VER
causes foo and foo@@VER to be output to the .o file. This requires foo
to be weak since the linker handles foo@@VER as foo.

Usi

use @@@ instead of @@ in __sym_default

Using
.symver foo,foo@@VER
causes foo and foo@@VER to be output to the .o file. This requires foo
to be weak since the linker handles foo@@VER as foo.

Using
.symver foo,foo@@@VER
causes just foo@@ver to be output and avoid the need for making foo
weak. It also reduces the constraint on how exactly a linker has to
handle foo and foo@@VER being present.

Submitted by: Rafael Espíndola
Reviewed by: dim, kib
Differential Revision: https://reviews.freebsd.org/D11653

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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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Don't peek into MD structures from MI code. The getcontext(3) and
setcontext(3) functions check the validify of the mcontext_t structs.

Bandaid to stop failing on non-i386 platforms.
Add a big ugly #warning as a reminder.

Add signalcontext(), which lays down a signal frame onto a ucontext_t.

Reviewed by: deischen, julian
Approved by: -arch

Include <stddef.h> to fix build problem when namespace pollution
by <signal.h> (including <time.h> so that NULL is accidentally defined)
is removed.

Style nits.

Submitted by: bde

Add getcontext, setcontext, makecontext, and swapcontext. These
functions are defined in SUSv2 and the latest POSIX spec.

Thanks to Bernd Walter <ticso@cicely8.cicely.de> for helping debug my
alpha

Add getcontext, setcontext, makecontext, and swapcontext. These
functions are defined in SUSv2 and the latest POSIX spec.

Thanks to Bernd Walter <ticso@cicely8.cicely.de> for helping debug my
alpha assembly.

Approved by: -arch

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