rtld: add lockstate_wlocked()

querying the lockstate for write-locked state.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

rtld: some style in rtld_lock.c

rtld: add LD_NO_DL_ITERATE_PHDR_AFTER_FORK env var

which makes threaded fork ignore the phdr rtld lock, in particular
allowing the dl_iterate_phdr() to block in callback. The cost is that
the image

rtld: add LD_NO_DL_ITERATE_PHDR_AFTER_FORK env var

which makes threaded fork ignore the phdr rtld lock, in particular
allowing the dl_iterate_phdr() to block in callback. The cost is that
the image started in this mode cannot use dl_iterate_phdr() after fork.

PR: 280318
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

show more ...

Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

show more ...

rtld: style the rest of rtld_lock.c

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36396

rtld: mask signals for default read locks

Rtld locks from libthr defer signals delivery, which means that binding
is not possible while a signal handler is executed.

Binding might upgrade read-lock

rtld: mask signals for default read locks

Rtld locks from libthr defer signals delivery, which means that binding
is not possible while a signal handler is executed.

Binding might upgrade read-locked rtld_bind_lock to write-lock, if
symbol resolution requires loading filters. If a signal would be delivered
while rtld is in read-locked section, and signal handler needs binding
which upgrades the lock, for non-threaded image that uses default rtld
locks, we get the rtld data structures modified under the top-level
active rtld frame.

To correct the problem, mask signals for read-locking of default locks
in addition to the write-locking. It is very cheap now with
sigfastblock(2).

Note that the global state is used to track pre-locked state of either
sigfastblock(2) or signal mask (if sigfastblock(2) is administratively
disabled). It is fine for non-threaded images since there are no other
threads. But I believe that it is fine for threaded images using libc_r
as well, since masking signals disables preemption (I did not tested
it).

NetBSD PR: https://gnats.netbsd.org/56979
Reported by: tmunro
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36396

show more ...

rtld: initialize default dlerror_seen_val as true

There should be no error after startup.

PR: 255698
Reported by: Eugene M. Kim <astralblue@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after

rtld: initialize default dlerror_seen_val as true

There should be no error after startup.

PR: 255698
Reported by: Eugene M. Kim <astralblue@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

show more ...

rtld: make dlerror() thread-local

PR: 95339
Discussed with: arichardson
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D29633

rtld: workaround for broken ABI

Right now, libthr does not initialize RtldLockInfo.rtli_version when calling
_rtld_thread_init(), which makes versioning the interface troublesome.

Add a workaround:

rtld: workaround for broken ABI

Right now, libthr does not initialize RtldLockInfo.rtli_version when calling
_rtld_thread_init(), which makes versioning the interface troublesome.

Add a workaround: if the calling object of _rtld_thread_init() exports
the "_pli_rtli_version" symbol, then consider rtli_version initialized.
Otherwise, forcibly set it to RTLI_VERSION_ONE, currently defined as
RTLI_VERSION.

Export "_pli_rtli_version" from libthr and properly initialize rtli_version.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D29633

show more ...

rtld: unstaticise lockinfo and obj_from_addr()

Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D29633

Merge ^/head r357662 through r357854.

Use sigfastblock(2) in rtld.

This allows for rtld to not issue two sigprocmask(2) syscalls for each
symbol binding operation in single-threaded processes. Rtld needs to
block signals as part of loc

Use sigfastblock(2) in rtld.

This allows for rtld to not issue two sigprocmask(2) syscalls for each
symbol binding operation in single-threaded processes. Rtld needs to
block signals as part of locking to ensure signal safety of the bind
process, because signal handlers might need to lazily resolve symbol
references.

As result, number of syscalls issued on startup by simple programs not
using libthr, is typically reduced 2x. For instance, for hello world,
I see:
non-sigfastblock
# (truss ./hello > /dev/null) |& wc -l
63
sigfastblock
# (truss ./hello > /dev/null) |& wc -l
37

Tested by: pho
Disscussed with: cem, emaste, jilles
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D12773

show more ...

MFHead @r350386

Sponsored by: The FreeBSD Foundation

Reduce size of rtld by 22% by pulling in less code from libc

Currently RTLD is linked against libc_nossp_pic which means that any libc
symbol used in rtld can pull in a lot of depedencies. This was

Reduce size of rtld by 22% by pulling in less code from libc

Currently RTLD is linked against libc_nossp_pic which means that any libc
symbol used in rtld can pull in a lot of depedencies. This was causing
symbol such as __libc_interposing and all the pthread stubs to be included
in RTLD even though they are not required. It turns out most of these
dependencies can easily be avoided by providing overrides inside of rtld.

This change is motivated by CHERI, where we have an experimental ABI that
requires additional relocation processing to allow the use of function
pointers inside of rtld. Instead of adding this self-relocation code to
RTLD I attempted to remove most function pointers from RTLD and discovered
that most of them came from the libc dependencies instead of being actually
used inside rtld.

A nice side-effect of this change is that rtld is now 22% smaller on amd64.

text data bss dec hex filename
0x21eb6 0xce0 0xe60 145910 239f6 /home/alr48/ld-elf-x86.before.so.1
0x1a6ed 0x728 0xdd8 113645 1bbed /home/alr48/ld-elf-x86.after.so.1

The number of R_X86_64_RELATIVE relocations that need to be processed on
startup has also gone down from 368 to 187 (almost 50% less).

Reviewed By: kib
Differential Revision: https://reviews.freebsd.org/D20663

show more ...

Merge ^/head r339813 through r340125.

rtld-elf: fix more warnings to allow compiling with WARNS=6

Reviewed By: kib
Approved By: brooks (mentor)
Differential Revision: https://reviews.freebsd.org/D17154

rtld: add lockstate_wlocked()

querying the lockstate for write-locked state.

Sponsored by: The FreeBSD Foundation
MFC after: 1 week

rtld: some style in rtld_lock.c

rtld: add LD_NO_DL_ITERATE_PHDR_AFTER_FORK env var

which makes threaded fork ignore the phdr rtld lock, in particular
allowing the dl_iterate_phdr() to block in callback. The cost is that
the image

rtld: add LD_NO_DL_ITERATE_PHDR_AFTER_FORK env var

which makes threaded fork ignore the phdr rtld lock, in particular
allowing the dl_iterate_phdr() to block in callback. The cost is that
the image started in this mode cannot use dl_iterate_phdr() after fork.

PR: 280318
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

show more ...

Remove $FreeBSD$: one-line .h pattern

Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

show more ...

rtld: style the rest of rtld_lock.c

Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36396

rtld: mask signals for default read locks

Rtld locks from libthr defer signals delivery, which means that binding
is not possible while a signal handler is executed.

Binding might upgrade read-lock

rtld: mask signals for default read locks

Rtld locks from libthr defer signals delivery, which means that binding
is not possible while a signal handler is executed.

Binding might upgrade read-locked rtld_bind_lock to write-lock, if
symbol resolution requires loading filters. If a signal would be delivered
while rtld is in read-locked section, and signal handler needs binding
which upgrades the lock, for non-threaded image that uses default rtld
locks, we get the rtld data structures modified under the top-level
active rtld frame.

To correct the problem, mask signals for read-locking of default locks
in addition to the write-locking. It is very cheap now with
sigfastblock(2).

Note that the global state is used to track pre-locked state of either
sigfastblock(2) or signal mask (if sigfastblock(2) is administratively
disabled). It is fine for non-threaded images since there are no other
threads. But I believe that it is fine for threaded images using libc_r
as well, since masking signals disables preemption (I did not tested
it).

NetBSD PR: https://gnats.netbsd.org/56979
Reported by: tmunro
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D36396

show more ...

rtld: initialize default dlerror_seen_val as true

There should be no error after startup.

PR: 255698
Reported by: Eugene M. Kim <astralblue@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after

rtld: initialize default dlerror_seen_val as true

There should be no error after startup.

PR: 255698
Reported by: Eugene M. Kim <astralblue@gmail.com>
Sponsored by: The FreeBSD Foundation
MFC after: 1 week

show more ...