Commit Graph
5333 Commits
Author SHA1 Message Date
Luca Boccassi 3b00327fe6 test: bump test-execute subtest timeout in CI
The test is flaky and times out lately in ppc64el CI runners:

exec-dynamicuser-statedir.service: Control group is empty.
exec-dynamicuser-statedir.service: User lookup succeeded: uid=65325 gid=65325
Test timeout when testing exec-dynamicuser-statedir.service

Bump the timeout also when in a CI, as they are often over subscribed
2026-06-05 09:47:02 +01:00
Yu Watanabe 1146c355f4 test: add missing bpf dependency
Fixes the following build error:
```
ninja: job failed: cc (snip) -o test-bpf-restrict-fsaccess.p/src_test_test-bpf-restrict-fsaccess.c.o -c ../src/test/test-bpf-restrict-fsaccess.c
In file included from ../src/test/test-bpf-restrict-fsaccess.c:96:
src/bpf/restrict-fsaccess-skel.h:19:10: fatal error: restrict-fsaccess.bpf.skel.h: No such file or directory
   19 | #include "restrict-fsaccess.bpf.skel.h"    /* IWYU pragma: export */
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
ninja: subcommand failed
```

Follow-up for e6fc73350f.
2026-06-05 04:59:11 +09:00
Yu Watanabe e0f02425ae test-namespace: namespace_open_by_id() may return -ESTALE for permission reasons
As commented in namespace_open_by_id().

Follow-up for 23f2204718.
2026-06-05 04:57:53 +09:00
Yu Watanabe 8dc1de8b3f test-btrfs: quota test is slow
The quota test takes ~30 seconds on my poor laptop, and randomly fails
with timeout. Let's extend the timeout and skip the test case when slow
tests are disabled.
2026-06-05 04:42:14 +09:00
Zbigniew Jędrzejewski-Szmek 112b565756 Add DLOPEN macros that stamp the caller's ELF and use it to ensure executables list their dlopen dependencies (#42398)
Currently almost all the dlopens happen in libbasic or libshared code,
so the ELF dlopen notes all end up in libsystemd-shared. Many
distributions split this library and various binaries in separate
packages, and the library ends up with soft-dependencies, even though
many binaries are either completely useless or do not work at all with
the dlopen dependency. This also makes it impossible to know which
executable uses which dlopen dependency without inspecting the source
code.

If someone only wants to add the soft dependencies from libshared they
can just avoid parsing the executable binaries. By design the code in
libbasic/libshared still does the stamping too, at lower priorities, so
that libsystemd-shared will always list all the optional dependencies,
and if one wants to build a minimal system by default, they can just
parse libsystemd-shared dlopen notes, and ignore the individual
executables. But for many distribution the current setup is insufficient
and requires adding a ton of manual library dependencies, as many
executables become effectively broken or useless without the dlopen
dependencies installed (eg: resolved fails to start without libssl,
repart can do basically nothing without blkid, etc).

Add a new set of DLOPEN_<LIB> macros that wrap the dlopen_lib and also
pull in the ELF note voodoo, so that the callers get their ELF binaries
stamped too. Convert a bunch of callers to use the macro, and use
`required` dependencies for the callers that do not work without the
dlopen library being available.

The one caveat is that, in order to avoid duplicating the exact same
note in a binary due to multiple call sites, some `asm` voodoo is done
instead of the previous bare-C section-creating macro. The drawback of
this approach is that if `--gc-sections` is used to link the binary (as
we do), then binutils >= 2.36 is required for the `SHF_GNU_RETAIN` flag.
This effectively cuts off CentOS 9, so what I did here is adding an
override in meson to detect missing support, and drop `SHF_GNU_RETAIN`.
The build works, but on CentOS 9 there's no dlopen ELF notes anymore.
Given it's just that version, and it goes EOL next year, that seems ok
to me. The alternative is to drop the usage of `--gc-sections` on CentOS
9, or to accept duplicated notes everywhere, and both seem worse.

End result:

```
$ readelf --notes build/systemd-executor

Displaying notes found in: .note.gnu.property
  Owner                Data size 	Description
  GNU                  0x00000010	NT_GNU_PROPERTY_TYPE_0
      Properties: x86 ISA needed: x86-64-baseline

Displaying notes found in: .note.gnu.build-id
  Owner                Data size 	Description
  GNU                  0x00000014	NT_GNU_BUILD_ID (unique build ID bitstring)
    Build ID: 8a0c3db54adb79ae54e1432255011aa4ab583742

Displaying notes found in: .note.ABI-tag
  Owner                Data size 	Description
  GNU                  0x00000010	NT_GNU_ABI_TAG (ABI version tag)
    OS: Linux, ABI: 3.2.0

Displaying notes found in: .note.dlopen
  Owner                Data size 	Description
  FDO                  0x0000006b	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"pam","description":"Support for LinuxPAM","priority":"recommended","soname":["libpam.so.0"]}]
  FDO                  0x0000007c	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"seccomp","description":"Support for Seccomp Sandboxes","priority":"recommended","soname":["libseccomp.so.2"]}]
  FDO                  0x00000090	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"bpf","description":"Support firewalling and sandboxing with BPF","priority":"recommended","soname":["libbpf.so.1","libbpf.so.0"]}]
  FDO                  0x000000a0	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"cryptsetup","description":"Support for disk encryption, integrity, and authentication","priority":"recommended","soname":["libcryptsetup.so.12"]}]
  FDO                  0x00000078	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"mount","description":"Support for mount enumeration","priority":"recommended","soname":["libmount.so.1"]}]

$ readelf --notes build/systemd

Displaying notes found in: .note.gnu.property
  Owner                Data size 	Description
  GNU                  0x00000010	NT_GNU_PROPERTY_TYPE_0
      Properties: x86 ISA needed: x86-64-baseline

Displaying notes found in: .note.gnu.build-id
  Owner                Data size 	Description
  GNU                  0x00000014	NT_GNU_BUILD_ID (unique build ID bitstring)
    Build ID: dcd4568842e32da3e71be27db3def51c6b459994

Displaying notes found in: .note.ABI-tag
  Owner                Data size 	Description
  GNU                  0x00000010	NT_GNU_ABI_TAG (ABI version tag)
    OS: Linux, ABI: 3.2.0

Displaying notes found in: .note.dlopen
  Owner                Data size 	Description
  FDO                  0x00000075	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"mount","description":"Support for mount enumeration","priority":"required","soname":["libmount.so.1"]}]
  FDO                  0x00000072	FDO_DLOPEN_METADATA
    Dlopen Metadata: [{"feature":"selinux","description":"Support for SELinux","priority":"recommended","soname":["libselinux.so.1"]}]
```
2026-06-02 18:05:34 +02:00
Luca Boccassi b240ce9642 ci: add build/unit-test coverage for armv7 (#42386)
arm64 hosts support running armv7 (armhf) binaries, so we can
cross compile and run the unit tests without performance issues.

armv7 (armhf) is a primary architecture on Ubuntu, so build
regressions block new version updates, and adding coverage
helps to avoid introducing regressions.
2026-06-02 13:15:50 +01:00
Luca Boccassi b0ede9f9ee tree-wide: convert dlopen_*() callers to DLOPEN_* wrapper macros
Switch the executable-owned call sites from the plain dlopen_<lib>()
helpers to the new DLOPEN_<LIB>() macros, so that each binary that loads
an optional library at runtime now carries its own .note.dlopen note
instead of relying solely on libsystemd-shared. Each call site passes a
priority reflecting whether it hard-depends on the library (required) or
degrades gracefully without it (recommended).

Co-developed-by: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-01 18:46:24 +01:00
Lennart Poettering 95c7dc3308 hostname-util: don't allow machine tags to begin/end with '-' or '.' 2026-06-01 12:16:28 +01:00
Luca Boccassi 595d3d593c test: skip test-execute and ukify addon test when cross-compiling
These tests run native tools on foreign ELF files, so they fail,
just skip them when cross-compiling
2026-05-29 17:48:52 +01:00
Luca Boccassi 0fd7b5ea5f test: avoid false maybe-uninitialized warning
2026-05-29T16:05:02.6627742Z In file included from ../src/basic/../fundamental/assert-util.h:8,
2026-05-29T16:05:02.6628349Z                  from ../src/basic/assert-util.h:4,
2026-05-29T16:05:02.6628722Z                  from ../src/basic/basic-forward.h:17,
2026-05-29T16:05:02.6629044Z                  from ../src/libsystemd/sd-common/sd-forward.h:6,
2026-05-29T16:05:02.6629361Z                  from ../src/shared/shared-forward.h:6,
2026-05-29T16:05:02.6629648Z                  from ../src/shared/crypto-util.h:4,
2026-05-29T16:05:02.6631153Z                  from ../src/test/test-crypto-util.c:3:
2026-05-29T16:05:02.6634148Z ../src/test/test-crypto-util.c: In function ‘test_digest_size’:
2026-05-29T16:05:02.6634986Z ../src/basic/../fundamental/macro.h:95:41: error: ‘size’ is used uninitialized [-Werror=uninitialized]
2026-05-29T16:05:02.6635470Z    95 | #define _unlikely_(x) (__builtin_expect(!!(x), 0))
2026-05-29T16:05:02.6635764Z       |                                         ^~~~~
2026-05-29T16:05:02.6636287Z ../src/basic/../fundamental/assert-util.h:59:21: note: in expansion of macro ‘_unlikely_’
2026-05-29T16:05:02.6636963Z    59 |                 if (_unlikely_(!(expr)))                                \
2026-05-29T16:05:02.6637344Z       |                     ^~~~~~~~~~
2026-05-29T16:05:02.6637864Z ../src/basic/../fundamental/assert-util.h:65:25: note: in expansion of macro ‘assert_message_se’
2026-05-29T16:05:02.6638339Z    65 | #define assert_se(expr) assert_message_se(expr, #expr)
2026-05-29T16:05:02.6638642Z       |                         ^~~~~~~~~~~~~~~~~
2026-05-29T16:05:02.6639066Z ../src/test/test-crypto-util.c:136:17: note: in expansion of macro ‘assert_se’
2026-05-29T16:05:02.6639450Z   136 |                 assert_se(size == t->size);
2026-05-29T16:05:02.6639704Z       |                 ^~~~~~~~~
2026-05-29T16:05:02.6640063Z ../src/test/test-crypto-util.c:132:16: note: ‘size’ declared here
2026-05-29T16:05:02.6640590Z   132 |         size_t size;
2026-05-29T16:05:02.6640794Z       |                ^~~~
2026-05-29 17:48:50 +01:00
jeffhuang 0c5cba6420 pe-binary: bound section data against file size, cap UKI zero-padding hash, validate optional header size
A hostile but structurally valid 382-byte PE32+ "EFI application" with a
single section whose VirtualSize is ~4 GiB and SizeOfRawData is 0 drives
uki_hash() into ~4.17 M iterations of SHA-256 over 1024 bytes of zeros
— wedging the parser for >10 s. Nine more slow-units share the same
shape. A separate MSAN finding from the new fuzzer (CIFuzz, memory
sanitizer) shows pe_load_headers() reading uninitialised heap memory
when SizeOfOptionalHeader is too small to actually contain
NumberOfRvaAndSizes.

Three tightenings in src/shared/pe-binary.c:

  1. In pe_load_sections, reject sections whose PointerToRawData +
     SizeOfRawData exceeds the actual file size. Raw section data must
     fit inside the file; this is the parser-wide invariant
     pe_hash / uki_hash / pe_read_section_data rely on.

  2. In uki_hash, cap the (VirtualSize - SizeOfRawData) zero-padding
     hash loop at 64 MiB. Real UKIs do not pad sections with tens of
     MiB of zero-equivalent data; anything above this cap is a
     malformed PE.

  3. In pe_load_headers, reject a PE whose SizeOfOptionalHeader is too
     small to cover up to NumberOfRvaAndSizes. Without this guard the
     subsequent size-mismatch check reads uninitialised optional-header
     bytes, caught by MSAN under CIFuzz.

Add the 382 B canonical reproducer (plus two structural siblings) and
the MSAN reproducer to test/fuzz/fuzz-pe-binary/. Also add a libFuzzer
harness in src/fuzz/fuzz-pe-binary.c and unit tests in
src/test/test-pe-binary.c that exercise each fix branch in isolation.
The 64 MiB hash boundary test is gated behind SYSTEMD_SLOW_TESTS so it
doesn't slow down emulated-arch CI.

This is a robustness fix, not a security fix: PE binaries consumed by
bootctl / systemd-stub / pcrlock / kernel-install / systemd-measure are
already trusted and signed at the consumer side, so the worst pre-fix
behaviour is wasted CPU on a UKI install / measure / inspect call.

Closes #42344.

Reported-by: AI-assisted libFuzzer campaign
Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-29 04:30:48 +09:00
Yu Watanabe 68af89e619 meson: move simple test entries 2026-05-28 16:44:29 +09:00
Daan De Meyer d4aa9dcda5 test: stop using PATH_TEST()/QMP_TEST() macro to make not confuse gcc/gcov/lcov (#42338) 2026-05-28 09:33:22 +02:00
Yu Watanabe 071493c725 test-pressure: set timeout to make not wait forever
If this runs on a slow or busy machine, then we may not get enough
pressure to trigger the event sources. In such case, the test does not
finish. It is problematic when the test is _not_ run with 'meson test',
e.g. debian/ubuntu CIs.

Let's introduce a timeout for each event loop, and skip test cases
gracefully.
2026-05-27 21:34:04 +01:00
Yu Watanabe 521153fe5b test-qmp-client: drop QMP_TEST() macro
Similar to the previous commit for test-path.
The macro confuses gcc/gcov/lcov:
```
lcov: ERROR: lcov: ERROR: (inconsistent) mismatched end line for test_qmp_client_basic_body at
/home/runner/work/systemd/systemd/src/test/test-qmp-client.c:204:
204 -> 224 while capturing from build/mkosi.builddir/arch~rolling~x86-64/test-qmp-client.p/src_test_test-qmp-client.c.gcno
```

The macro itself is not bad, but does not reduce lines so much.
Let's stop using the macro.
2026-05-28 01:46:38 +09:00
Yu Watanabe f5678af9c7 test-path: coding style cleanups 2026-05-28 01:23:48 +09:00
Yu Watanabe bd6b38d74e test-path: drop PATH_TEST() macro
The macro was introduced by fc7a32df38,
but unfortunately gcc/gcov/lcov are confused by the macro:
```
lcov: ERROR: lcov: ERROR: (inconsistent) mismatched end line for test_path_exists_body at
/home/runner/work/systemd/systemd/src/test/test-path.c:158:
158 -> 185 while capturing from build/mkosi.builddir/arch~rolling~x86-64/test-path.p/src_test_test-path.c.gcno
(use "lcov --ignore-errors inconsistent ..." to bypass this error)
```

The macro deos nothing spurious, hence it should be a bug in gcc.
But, the macro just reduces the lines for calling setup_test(), and
does not simplify test cases so much.
Let's call it in each test cases, and stop using the macro.
2026-05-28 01:23:48 +09:00
nikstur b4aff10ac0 meson: fix building without logind (#42324)
Otherwise you cannot build systemd (e.g. just the libs) without logind.

Follow-up for 1f9fb6300b
2026-05-26 23:45:18 +01:00
Yu Watanabe 754737ddc3 test-execute: reenable the test with sanitizers 2026-05-26 14:30:22 +02:00
Daan De Meyer e098b57810 test-pressure: Fix checks
Follow up for 7e250f70
2026-05-26 00:03:20 +01:00
Yu Watanabe ba8f9b6cc1 Revert "test: skip tpm2 test on s390x on GHA"
This reverts commit b735d01c8a.

Closes #38229.
2026-05-25 22:17:00 +01:00
Yu Watanabe 21c91145ff test-execute: drop workaround for fixed issue
The issue should be already fixed by f01f70a9a3.
2026-05-25 22:16:16 +01:00
Yu Watanabe c84bef3756 logind: migrate to Varlink (phase1) (#41561)
This implements phase 1 of #41560.

Add List Varlink methods for all logind object types (sessions, users,
seats, inhibitors).
2026-05-26 03:15:55 +09:00
Yu Watanabe ff5cd0b8da Add $SYSTEMD_INVOKED_AS (#42286) 2026-05-26 02:25:08 +09:00
Zbigniew Jędrzejewski-Szmek 58e7959988 Add $SYSTEMD_INVOKED_AS
This allows multi-call binaries to be easily invoked with a different
name. After installation, the name is set by creating a symlink. But in
build directories, we don't create the symlinks. (There are also other
ways to achieve the same thing, e.g. zsh supports $ARGV0, and exec -a
can be used, but those are either non-portable or are more complicated
to use.)  The primary use-case for me is to test --help output for
multicall binaries.

Also reorder the help for env vars to group the more generic ones near
the top.

This was initially proposed in https://github.com/systemd/systemd/pull/24054,
but there were some comments about the implementation. I had a branch
with the patch, but I don't think I ever actually submitted it as a
pull request.
2026-05-25 12:37:36 +02:00
Daan De Meyer d60cf3702a test-pressure: Skip if controller didn't get enabled
If for any reason the controller didn't get enabled on the
scope, skip the test.
2026-05-24 22:36:27 +01:00
Luca Boccassi 6abf89be6e test: fix test-fileio leaving directory behind and failing on rerun
/* test_write_data_file_atomic_at */
src/test/test-fileio.c:740: Assertion failed: Expected "write_data_file_atomic_at(XAT_FDROOT, "tmp/zzz/wdfa", &a, 0)" to fail with error -2/ENOENT, but it succeeded

Follow-up for 6738762688
2026-05-22 16:41:56 +01:00
Luca Boccassi b6796048d9 test: fix test-fileio failure in gitlab CI container
Follow-up for 6738762688
2026-05-22 16:37:06 +01:00
Luca Boccassi b261762c82 meson: fix build with -Dmachine=false
Fixes https://github.com/systemd/systemd/issues/42257

Follow-up for 5d0ac2c23c
2026-05-22 16:03:47 +01:00
Rocker Zhang 851ee29a54 test: cover LUO serialize-side anti-hijack guard in TEST-91
manager_luo_serialize_fd_stores() refuses to serialize a unit fd store
entry that holds a child LUO session named like PID 1's own ("systemd"),
to stop a service from hijacking PID 1's reserved session namespace
across kexec. That guard had no test coverage.

Add a test-luo store-hijack/check-hijack subcommand pair: on the first
boot a system service preserves a child LUO session named "systemd" in
its fd store; after kexec the test asserts the entry was not restored --
the unit's NFileDescriptorStore is 0, and check-hijack, run as the unit's
own second-boot ExecStart, confirms the hijack fd is absent from its
restored LISTEN_FDNAMES -- proving PID 1 skipped it during serialization.

The restore-side guards (corrupt mapping, reserved token 0, invalid unit
name, missing child session) are intentionally not covered: they only run
against PID 1's own "systemd" session built by luo_preserve_fd_stores(),
which a cooperating userspace helper cannot corrupt without racing or
displacing PID 1 (it single-owns /dev/liveupdate at shutdown). Triggering
them reliably would need kernel fault injection.

Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-22 12:00:05 +01:00
Yaping Li d2bdaab55e logind: add ListInhibitors Varlink method
The Varlink ListInhibitors method is the counterpart of D-Bus
ListInhibitors. Like its D-Bus counterpart it is zero-filter and streams
the full list of currently registered inhibitors using the
SD_VARLINK_METHOD_MORE pattern, returning InhibitorInfo objects with
Id, What, Who, Why, Mode, UID, PID, and Since fields.

There is no D-Bus GetInhibitor getter to fold in, so no unique-key
filter is introduced here.
2026-05-22 02:56:24 +00:00
Yaping Li 1f9fb6300b logind: add ListSessions Varlink method
The Varlink ListSessions method accepts optional Id and PID filters,
folding in the D-Bus GetSession(s) and GetSessionByPID(u) lookups.

Passing a unique-key filter (Id and/or PID) yields a single reply on
match, or NoSuchSession on miss. Passing no filter streams the full
list (requires the 'more' flag). Specifying both Id and PID acts as a
consistency check: both must refer to the same session, otherwise
NoSuchSession is returned.

The Id filter supports the special names "self" and "auto" which
resolve to the caller's session. The SessionInfo type in the
io.systemd.Login Varlink IDL carries all session properties matching
the D-Bus org.freedesktop.login1.Session interface.
2026-05-22 02:56:24 +00:00
Yu Watanabe 580bd17d90 Use malloc'ed strings instead of static libc buffers for user and group lookup (#42184)
Preparation for other work.
2026-05-22 05:09:56 +09:00
Lennart Poettering 461ec6facc condition: add a condition that matches against the machine tags 2026-05-21 18:30:16 +02:00
Lennart Poettering 1b94530b14 hostnamed: introduce "machine tags" concept
For management purposes it's useful to be able to "tag" a machine with
various labels. Let's add a field for that to /etc/machine-info and make
it settable.

Fixes: #38591
2026-05-21 18:30:16 +02:00
Lennart Poettering 740a5ce947 core: introduce ConditionFraction= that is true on a certain percantage of the fleet 2026-05-21 18:19:07 +02:00
Zbigniew Jędrzejewski-Szmek c83ff0e58d user-util: return malloc'ed strings in get_user_creds
get_user_creds would use getpwnam() and then returns strings pointing
into the static buffer. This seems very iffy. Let's duplicate the
strings properly
2026-05-21 18:02:05 +02:00
Zbigniew Jędrzejewski-Szmek 3ecd6b69cf user-util: stop mangling groupname in get_group_creds
The param was input/output, which is unexpected and confusing and
actually made most callers much more complicated than they needed to be.
The function was playing fast and loose with the return value. In some
cases it was returning a static string, which would be completely fine.
But in other case it was returning a pointer into the getgrgid static
buffer, i.e. that return value could be overwritten. AFAICT, this didn't
matter in any of the callers, but we shouldn't do that anyway.

So use a separate output param with an allocated string that the caller
is responsible for.

It turns out that all callers pass NULL (outside of tests) and zero for
flags. So the function _could_ be simplified. But get_user_creds is
called with all the params actually used, and I think having the the
functions so different wouldn't be nice. I first wrote a commit to
drop the unused params, but then I discarded it.

The error message in exec-invoke.c is fixed.
2026-05-21 18:02:05 +02:00
Daan De Meyer 06e32e4b61 Introduce support for running code in fibers (#39771)
Traditionally, asynchronous programming in systemd has been achieved
using
sd-event along with the asynchronous interfaces of sd-bus and
sd-varlink.
This works well when the system is reacting to events and all code
triggered
by those events can run without blocking. In these scenarios, the global
Manager object is passed as userdata to the callback, and the callback
can
use the stack as usual, declaring local state and ensuring proper
cleanup via
_cleanup_. Control flow structures, such as loops, work as expected, and
everything runs smoothly.

However, challenges arise when the code needs to perform long-running
operations within these callbacks. Since the system cannot block
execution
within the callback, we can't directly invoke a long-running operation
and
wait for its result without introducing complexities. Instead, we need
to
initiate the long-running task, register for completion with sd-event,
sd-bus, or sd-varlink, and provide a callback to be invoked when the
operation completes.

This callback, however, only receives a single userdata pointer, which
forces us to bundle all local variables into a struct and pass it along
as
part of the callback. On top of that, after queuing the asynchronous
operation, the caller continues executing. As the caller's stack unwinds
when the function exits, the resources and state within the local scope
may
be prematurely cleaned up. Therefore, the struct must store copies of
the
local variables or ensure proper reference counting to prevent premature
resource cleanup.

When multiple long-running operations need to be initiated within a
loop,
the complexity grows further. We must introduce additional shared state
to
track the completion of all operations before we can run any code that
depends on their results.

Furthermore, since the daemon may be shut down at any time, we must
track
the lifecycle of each long-running operation in the global Manager
struct,
ensuring proper cleanup even when stack unwinding can no longer manage
the
resources for us.

Fibers, or green threads, provide a more natural way of handling
asynchronous operations. By enabling cooperative multitasking within a
single thread, fibers allow us to write code that looks like it’s
running
synchronously, but with the ability to yield control at predefined
points,
such as when waiting for long-running tasks to complete.

With fibers, we can simplify the control flow by running asynchronous
operations within a fiber, allowing us to "pause" execution while
waiting
for the long-running operation to finish and then "resume" the operation
once
it's complete. This eliminates the need for multiple callback chains,
extensive state tracking, and the potential pitfalls of stack unwinding.

This commit introduces the ability to execute long-running operations in
a
non-blocking manner while maintaining the simplicity and readability of
synchronous code. The fiber-based approach will significantly improve
the
handling of complex workflows, making the code easier to write and
maintain.

The implementation is based on ucontext.h's makecontext() (with a
fallback
to the venerable sigaltstack() approach on musl),
sigsetjmp()/siglongjmp()
and sd-event. ucontext.h provides us with alternate stacks that we can
switch
between. We use sigsetjmp()/siglongjmp() instead of swapcontext()
because the
latter forcibly saves/restores a per context signal mask every time it
is called.
Using sigsetjmp()/siglongjmp(), we can avoid the unnecessary syscall and
maintain
a per thread signal mask, which makes much more sense than having a per
fiber
signal mask.

The default stack size is the same as a regular thread. Because we 
use mmap() to allocate the stack, the memory won't actually be used
until it
is paged in by the kernel, so we don't actually use 8MB per fiber.

To integrate fibers with the event loop, each fiber is assigned a
deferred
event source which resumes the fiber when enabled. The deferred event
source
is oneshot by default so the fiber will run immediately until it yields
or
suspends. If it yields, the deferred event source is enabled again
(oneshot)
immediately. If it suspends, before it suspends, one or more event
sources
are registered with sd-event that will enable the deferred event source
(oneshot) to resume the fiber once the operation it is waiting for
completes.

Yielding or suspending the fiber is done by calling sd_fiber_yield() or
sd_fiber_suspend() respectively. Both of these return zero on success or
any
error value from the async operation that caused the fiber to resume.

This is also how fiber cancellation is implemented. When a fiber is
cancelled,
sd_fiber_yield() and sd_fiber_suspend() will return ECANCELED when the
fiber
is resumed, allowing the fiber to unwind its stack (which allows cleanup
to
happen automatically) and finish.

Instead of having applications work directly with fibers, we hide them
behind
a generic futures interface to represent long-running operations,
regardless of
whether those operations are running on a fiber or not. Aside from
fibers, the
futures library (sd-future) will for example allow waiting for sd-event
sources
and doing sd-bus calls in the background as well. Fibers can suspend
until a
future is ready with sd_fiber_await() or by having the future wake up
the fiber
explicitly in its callback. A future always defaults to waking up the
current
fiber.

Each future kind plugs into the library by providing an sd_future_ops
vtable
(alloc, free, cancel, set_priority). The library treats the impl pointer
returned by alloc() as a black box. Future Implementations retrieve it
via
sd_future_get_private().

A future starts in SD_FUTURE_PENDING and transitions exactly once to
SD_FUTURE_RESOLVED, carrying an integer result. Consumers can react to
that
transition either by installing a one-shot callback with
sd_future_set_callback() (callback-style code) or by waiting on it from
a
fiber via sd_fiber_await() (synchronous-looking fiber code).
sd_fiber_await()
is itself built on a "wait future" that resolves when its target
resolves;
sd_future_new_wait() exposes the same primitive directly so non-fiber
callers
can chain futures without involving a fiber.

Cancellation is cooperative: sd_future_cancel() invokes the future
impl's
cancel callback, which is responsible for tearing down its work and
ultimately
resolving the promise with -ECANCELED. For fiber futures this is what
surfaces as the ECANCELED return from
sd_fiber_yield()/sd_fiber_suspend()
mentioned above.

Fire-and-forget fibers — created by passing a NULL ret to sd_fiber_new()
—
take a self-reference on their future so they outlive the caller's
scope.
The self-ref is dropped when the fiber resolves. This floating mechanism
(sd_fiber_set_floating()) is restricted to fiber futures because they
uniquely guarantee resolution; allowing it for arbitrary future kinds
would
risk silent leaks for kinds that may never resolve.

Note that fiber cleanup depends on the runtime operating normally. Each
fiber's _cleanup_-style cleanups live on the fiber's own stack and run
only when the fiber is resumed and allowed to unwind, which requires a
working event loop to drive it to completion. The exit event source
registered for top-level fibers ensures unwind on a normal
sd_event_exit(),
but if the event loop itself terminates abnormally (e.g. an
unrecoverable
allocation failure mid-dispatch) before all fibers have resolved, their
stacks never unwind and any resources they own leak.

The code lives in libsystemd as sd-future (not exported) for the
following reasons:
- We may want to make this a public libsystemd API in the future
- The code can't live in src/basic as it makes heavy use of sd-event
- The code can't live in src/shared as sd-bus and sd-event make use of
it

The log and log-context headers are updated with functions to allow
fibers to have their own log prefix and log context.
2026-05-21 16:21:13 +02:00
Luca Boccassi 20615d2d47 core: add FileDescriptorStorePreserve=on-success option (#42160)
Currently with FileDescriptorStorePreserve=yes the FD store is kept
around
regardless of what happens to a unit, which is useful in many cases. But
in
some cases, for example when complex services crash horribly, it's hard
to
reason about what was in the intermediate state, and it's better to
start
fresh.

Add a new 'on-success' option for the FileDescriptorStorePreserve=
setting
that keeps it around only for as long as the unit doesn't go to a
persistently
failed state.

This is especially useful in combination with LUO, where we don't want
to
keep around LUO sessions created by units that then proceeded to crash
and
burn, and might be in a bad state afterwards.
2026-05-21 12:08:33 +01:00
Daan De Meyer 05a4f7755a test-btrfs: skip info test when GET_SUBVOL_INFO ioctl is unsupported
On 32-bit userspace running against a 64-bit kernel
BTRFS_IOC_GET_SUBVOL_INFO returns -ENOTTY: struct
btrfs_ioctl_get_subvol_info_args embeds four btrfs_ioctl_timespec
values, and that timespec struct (__u64 sec; __u32 nsec) packs to 12
bytes on i386 but 16 on x86_64 due to differing __u64 alignment.
sizeof(struct) is part of the ioctl cmd number via _IOR(), so the cmd
emitted by 32-bit userspace doesn't match the case label compiled by
the 64-bit kernel and the switch falls through to -ENOTTY.

btrfs already handles this exact class of bug for
BTRFS_IOC_SET_RECEIVED_SUBVOL via a btrfs_ioctl_timespec_32 struct
plus a _32 cmd alias in fs/btrfs/ioctl.c, but GET_SUBVOL_INFO (added
in 2018, four years after that fix) didn't get the same treatment.
Until a kernel patch lands the test can't exercise the ioctl on
32-bit, so convert TEST(info) to TEST_RET(info) and return
EXIT_TEST_SKIP with a clear message when -ENOTTY comes back. The
other tests in the file use ioctls that already have working compat
paths and remain unaffected.
2026-05-21 12:06:21 +01:00
Daan De Meyer 56bc502f6f math-util: round to declared FP precision consistently across architectures
Add -fexcess-precision=standard so gcc inserts ISO C99 conformant
rounding at assignments, casts, and returns — without it, double values
on x87 happily stay at 80-bit extended precision across operations and
diverge from the SSE/x86_64 behavior, making strict equality comparisons
architecture-dependent.

The flag doesn't fully cover x87: per gcc PR#323
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=323), a function return
value carried in ST(0) can arrive at the caller still at 80-bit, so a
double that ought to compare equal to a same-magnitude literal picks up
extra mantissa bits and doesn't. Wrap fp_equal in volatile-double
temporaries to force a memory roundtrip — the only operation that
reliably truncates on x87 — so its callers get consistent results
regardless of how the operands were produced.

Add a TEST(fp_equal) case that exercises the previously-broken pattern:
a runtime 1.0/10.0 computed inside a noinline helper, returned across
the function ABI boundary, then compared against the literal 0.1.
Without the volatile truncation this assertion fails on 32-bit gcc.
2026-05-21 11:53:32 +01:00
Daan De Meyer 742733440f test-qmp-client: run mock QMP servers as fibers on the shared event loop
The mock servers used to be driven out-of-band: each test created a
socketpair, forked a child, ran a hand-coded request/response script
against the raw fd, and sent SIGTERM to tear it down. That worked but
required pidref/process-util/signal plumbing in every test, two
distinct execution contexts that couldn't share state, and a JsonStream
attached to the mock side that pretended to be event-loop-driven while
actually being driven manually via blocking reads.

Now that JsonStream suspends when on a fiber, the mocks can live
inside the same process and event loop as the client. Each mock is
rewritten as an sd-fiber that runs alongside the client fiber: so the 
mock fiber yields on I/O and the event loop schedules the client in the 
meantime. Both sides progress cooperatively, no fork/SIGTERM/PID tracking, 
no manual phase tracking.

Two cleanups fall out of the rewrite:

- A QMP_TEST(name, mock_fn) { ... } macro encapsulates the per-test
  scaffolding (event loop, socketpair, mock fiber spawn, exit-on-idle
  shim) and injects an already-connected QmpClient *client into the
  test body. Each test now reads as a flat sequence of
  qmp_client_call() invocations against that client.

- Repeated mock command/reply scripting is factored into
  mock_qmp_expect(), mock_qmp_reply(), mock_qmp_expect_and_reply(),
  mock_qmp_handshake(), and mock_qmp_query_status_running(). The
  greeting JSON is built with sd_json_buildo() instead of being parsed
  from a literal.

The file shrinks from 756 to 494 lines, mostly through deletions.
2026-05-21 09:55:04 +00:00
Daan De Meyer 37679d79a8 qmp-client: add fiber-aware call paths
The synchronous qmp_client_call() pumps the event loop until its reply
arrives, pinning the parsed reply on c->current so it can hand out
borrowed pointers to the caller. That model only fits one in-flight
sync call: a second qmp_client_call() on the same client clears
c->current before issuing its own send, invalidating the first
caller's borrowed pointers. On a single-threaded event loop that was
fine, but with fibers two concurrent calls on the same client can
interleave through the pump (json_stream_wait() suspends the running
fiber) and trample each other.

To fix this, make qmp_client_call() detect when it's running on a fiber 
whose event loop matches the client and transparently delegate to
qmp_client_call_suspend(), which makes use of a new QmpFuture to allow
multiple concurrent calls to qmp_client_call(). 

To make this work concurrently, we also change qmp_client_call() to 
hand out references and copies of errors so that we don't have to store
the borrowed pointers we hand out in the QmpClient struct.
2026-05-21 09:55:04 +00:00
Luca Boccassi 00276b963c test: avoid test-fdstore failing units when exiting
This is used as payload, so ensure the wrapping unit/container
doesn't register a failure when this exits

Follow-up for 9de91f0f4c
2026-05-21 10:13:17 +01:00
Daan De Meyer 74d392ed1b tree-wide: standardize header names across src/fundamental, src/basic and src/shared
Drop the -fundamental suffix from src/fundamental/ headers in favor of names
that match their src/basic/ or src/shared/ counterparts (e.g.
macro-fundamental.h -> macro.h, assert-fundamental.h -> assert-util.h,
cleanup-fundamental.h -> cleanup-util.h). Rename src/basic/{btrfs,label}.{c,h}
to use the -util suffix to match the existing shared/btrfs-util and
shared/label-util siblings. Rename src/shared/mkdir-label.{c,h} to mkdir.{c,h}
and src/shared/tmpfile-util-label.{c,h} to tmpfile-util.{c,h} to match the
corresponding src/basic names.

This saves us from having to come up with separate names for files that do
the same thing across tiers, and it makes it easier to move stuff between
src/fundamental, src/basic and src/shared: consumers just #include "foo.h"
and pick up whichever tier their -I path resolves to first, so call sites
don't need to be updated when an API moves between layers.

Where a higher-tier wrapper exists (e.g. src/basic/macro.h wrapping
src/fundamental/macro.h), the wrapper uses an explicit "../fundamental/foo.h"
or "../basic/foo.h" relative include for the lower-tier header. We can't use
GCC's #include_next directive for this — when the wrapper is reachable both
via same-dir-as-source lookup and via -I (e.g. -Isrc/shared) for the
directory it lives in, #include_next advances by exactly one slot in libcpp's
internal directory chain and lands on the same physical directory it was
already in, never reaching the lower-tier sibling (see make_cpp_dir() in
gcc/libcpp/files.cc:1986).

To make sure the right headers are always picked up, the include directories
are reordered so that e.g. src/shared always takes priority over src/basic and
similar for the other directories.

Co-developed-by: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-21 10:33:03 +09:00
Daan De Meyer 65f076f4b0 test-path: Skip test when we can't create a cgroup
Instead of having CI runner specific checks, let's just
skip the test if we get EXIT_CGROUP which is what we get
when we can't create a cgroup. This makes the check work
independently of CI runner, and specifically also on github
actions.
2026-05-20 17:22:35 +00:00
Daan De Meyer fc7a32df38 test-path: Migrate to test framework and macros
- Also clean up the logging in check_states() to
  only log on state changes so it's less noisy.
2026-05-20 16:04:26 +00:00
Daan De Meyer eb69a3c59d test-path: Fail earlier on start-limit-hit 2026-05-20 16:04:26 +00:00
Daan De Meyer 933a45835f basic/math-util: drop libm where possible
- test-random-util is reworked to not use sqrt()
- pretty-print.c inlines ceil() so libm doesn't have
  to be linked into libshared
- We add fno-math-errno to allow inlining of more math
  functions by not requiring standard math functions to 
  set errno on invalid input.
2026-05-20 16:32:22 +02:00