This also switches all these notes to be defined via SD_ELF_NOTE_DLOPEN_ANCHORED().
Consequently, any notes added within unreachable or unused functions will be
automatically garbage-collected by the linker (--gc-sections) instead of
bloating the final binary.
E.g. unused p11-kit library dependency is now dropped from
systemd-repart.standalone binary.
Before:
```
$ systemd-analyze dlopen-metadata build/systemd-repart.standalone
FEATURE DESCRIPTION SONAME PRIORITY
cryptsetup Support for disk encryption, integrity, and authentication libcryptsetup.so.12 recommended
blkid Support for block device identification libblkid.so.1 required
libcrypto Support for cryptographic operations libcrypto.so.4 libcrypto.so.3 recommended
mount Support for mount enumeration libmount.so.1 required
fdisk Support for reading and writing partition tables libfdisk.so.1 required
blkid Support for block device identification libblkid.so.1 recommended
libcrypto Support for cryptographic operations libcrypto.so.4 libcrypto.so.3 suggested
cryptsetup Support for disk encryption, integrity, and authentication libcryptsetup.so.12 suggested
fdisk Support for reading and writing partition tables libfdisk.so.1 suggested
idn Support for internationalized domain names libidn2.so.0 suggested
mount Support for mount enumeration libmount.so.1 recommended
selinux Support for SELinux libselinux.so.1 recommended
tpm Support for TPM libtss2-esys.so.0 suggested
tpm Support for TPM libtss2-rc.so.0 suggested
tpm Support for TPM libtss2-mu.so.0 suggested
tpm Support for TPM libtss2-tcti-device.so.0 suggested
p11-kit Support for PKCS11 hardware tokens libp11-kit.so.0 suggested
```
After:
```
$ systemd-analyze dlopen-metadata build/systemd-repart.standalone
FEATURE DESCRIPTION SONAME PRIORITY
cryptsetup Support for disk encryption, integrity, and authentication libcryptsetup.so.12 recommended
blkid Support for block device identification libblkid.so.1 required
libcrypto Support for cryptographic operations libcrypto.so.4 libcrypto.so.3 recommended
mount Support for mount enumeration libmount.so.1 required
fdisk Support for reading and writing partition tables libfdisk.so.1 required
blkid Support for block device identification libblkid.so.1 recommended
libcrypto Support for cryptographic operations libcrypto.so.4 libcrypto.so.3 suggested
cryptsetup Support for disk encryption, integrity, and authentication libcryptsetup.so.12 suggested
fdisk Support for reading and writing partition tables libfdisk.so.1 suggested
mount Support for mount enumeration libmount.so.1 recommended
selinux Support for SELinux libselinux.so.1 recommended
tpm Support for TPM libtss2-esys.so.0 suggested
tpm Support for TPM libtss2-rc.so.0 suggested
tpm Support for TPM libtss2-mu.so.0 suggested
tpm Support for TPM libtss2-tcti-device.so.0 suggested
```
The userns/netns/ipcns fdpairs were declared as plain int arrays without
_cleanup_close_pair_. If exec_shared_runtime_add() fails (e.g. OOM on
hashmap_ensure_put), the already-opened fds are leaked.
Since exec_shared_runtime_add() uses TAKE_FD on success, the array
entries are reset to -1 after ownership transfer, so adding
_cleanup_close_pair_ is safe and closes the fds only when they were
never consumed.
Signed-off-by: dongshengyuan <dongshengyuan@uniontech.com>
Allow systemd-executor to be compiled into a single binary.
The existing -Dlink-executor-shared=true|false is extended to also
allow -Dlink-executor-shared=single (*). The new mode is opt-in,
to allow experimentation and introduce this smoothly.
This saves a little space, but not as much as I expected:
$ ls -l build/{systemd,systemd-executor} build-new/systemd
-rwxr-xr-x 1 zbyszek zbyszek 631520 May 25 22:44 build/systemd
-rwxr-xr-x 1 zbyszek zbyszek 670464 May 25 22:44 build/systemd-executor
-rwxr-xr-x 1 zbyszek zbyszek 1214488 May 25 22:45 build-new/systemd
(This is with -Dbuildtype=debugoptimized -Db_lto=true).
The combined binary is slightly smaller than the sum of the separate
ones, but not much. In both cases, the binaries are linked to
libsystemd-core which is 10MB, so the size of the binaries themselves
doesn't make much of a difference. The executor needs exec-invoke.c
which is huge and not shared with anything else.
Longer term, I want to allow systemd to be linked statically. In
that case, having systemd-executor separate would be very painful.
So the option to use a multicall binary will be necessary.
Previously, we stored the resolved path to systemd-executor and
used it argv[0]. I don't think this was useful. After all, normally
we would use the non-resolved original path as argv[0]. So that
part is dropped, and the resolved path is only logged, but
"systemd-executor" is always used as argv[0]. This makes the
multicall binary work reliably, no matter what the actual file
name is.
(*) This means that compat as the commandline level is maintained:
'meson setup build -Dlink-executor-shared=true …' works as before.
Unfortunately, when using an existing build directory, meson chokes
on the type change and refuses to reconfigure the directory or change
the option or do anything useful. I think meson is DTWT here, but
this is hard to fix. So the build directory probably needs to be
recreated.
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>
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.
Extract the SetCredential{,Encrypted} logic out of
bus_exec_context_set_transient_property() into a new helper.
No functional changes.
This will be used in the varlink Unit.StartTransient SetCredential
implementation.
Until very recently all types defined by execute.h started with "Exec"
in the name. I think that was useful, since it made clear that the types
are associated with the ExecContext infrastructure. Let's hence restore
this.
(If we every move these types out of execute.h we should drop the "Exec"
prefix again. But today is not that day.)
No real code changes, just dumb renaming.
Every dlopen_xxx() helper now takes an int log_level argument. It is
passed through to dlopen_many_sym_or_warn() (which in turn propagates it
to dlopen_verbose() for the library-not-installed case), and is used by
the fallback stub when support for the library is not compiled in to
emit a "<lib> support is not compiled in." message at the caller's level.
Callers pass LOG_DEBUG when gracefully degrading, or a higher level when
the failure should surface, and no longer need to log redundantly at the
call site.
As part of this, dlopen_bpf_full() (which already took a log_level) is
merged into dlopen_bpf() rather than keeping both.
The static inline fallbacks used to live in the headers, which required
pulling log.h in from every header that declared a dlopen_xxx(). Move
them into the .c files instead: the declaration is always outside the
#if HAVE_XXX block, the impl sits outside the outer #if HAVE_XXX wrap
with its own internal #if HAVE_XXX/#else/#endif, and apparmor-util.c,
idn-util.c, libmount-util.c and pam-util.c are now always compiled so
they can host their stubs.
The updated parsing_hacks.h file uncovered a bunch of extra
things that the check-pointer-deref coccinelle script flags.
This commit fixes them to make the tree check-pointer-deref clean.
This is similar to DEFINE_POINTER_ARRAY_FREE_FUNC, but one
pointer chase less. The name of the outer and inner functions are
specified separately. The inner function does not free, so it'll
be generally something like 'foo_done', but the outer function
does free, so it can be called 'foo_array_free'.
Since v257, terminal_fix_size() is called during early boot via
console_setup() → reset_dev_console_fd() to query terminal dimensions
via ANSI escape sequences. This has caused intermittent boot hangs
where the system gets stuck with a blinking cursor and requires a
keypress to continue (see systemd/systemd#35499).
The function tries CSI 18 first, then falls back to DSR if that fails.
Previously, each method independently opened a non-blocking fd, disabled
echo/icanon, ran its query, restored termios, and closed its fd. This
created two problems:
1. Echo window between CSI 18 and DSR fallback: After CSI 18 times out
and restores termios (re-enabling ECHO and ICANON), there is a brief
window before DSR disables them again. If the terminal's CSI 18
response arrives during this window, it is echoed back to the
terminal — where the terminal interprets \e[8;rows;cols t as a
"resize text area" command — and the response bytes land in the
canonical line buffer as stale input that can confuse the DSR
response parser.
2. Cursor left at bottom-right on DSR timeout: The DSR method worked by
sending two DSR queries — one to save the cursor position, then
moving the cursor to (32766,32766) and sending another to read the
clamped position. If neither response was received (timeout), the
cursor restore was skipped (conditional on saved_row > 0), leaving
the cursor at the bottom-right corner of the terminal. The
subsequent terminal_reset_ansi_seq() then moved it to the beginning
of the last line via \e[1G, making boot output appear at the bottom
of the screen — giving the appearance of a hang even when the system
was still booting.
This commit fixes both issues:
- terminal_fix_size() now opens the non-blocking fd and configures
termios once for both query methods, so echo stays disabled for the
entire CSI 18 → DSR fallback sequence with no gap. tcflush(TCIFLUSH)
is called before each query to drain any stale input from the tty
input queue.
- The DSR method now uses DECSC (\e7) / DECRC (\e8) to save and restore
the cursor position via hardware, instead of querying it with a
separate DSR round-trip. All four sequences (DECSC, CUP to
bottom-right, DSR query, DECRC) are sent in a single write, so the
terminal processes DECRC and restores the cursor regardless of whether
userspace ever reads the DSR response. This eliminates the
cursor-at-bottom-right artifact on timeout and simplifies the read
loop to only need a single DSR response instead of two.
- The repeated setup boilerplate (dumb check, verify_same, fd_reopen,
termios save/disable) is extracted into terminal_prepare_query(),
shared by terminal_get_size_by_csi18(), terminal_get_size_by_dsr(),
and terminal_fix_size().
Fixes: systemd/systemd#35499
Co-developed-by: Claude Opus 4.6 <noreply@anthropic.com>
The only reason why ExecSharedRuntime.(var_)tmp_dir might
be suppressed is when (/var)/tmp/ is listed in InaccessiblePaths=,
in which case mount namespace is needed anyways. Moreover,
the current logic imposes a chicken-and-egg problem:
at various places in pid1 we'd need to check whether
the unit runs in a mountns, but the ExecSharedRuntime
may not be allocated for it just yet.
We have two very similar checks in place: in some contexts we want to
know if *any* RootDirectory= is configured, in the other we want to
suppress if it is configured to our regular root. Let's add a helper for
both (even if we only need it once), to make the mirrored behaviour
clear.
Currently mount options are handled in such a way that the first
definition for a given partition wins, and documented as such.
Change them so that they behave like other options, and the
last specified wins.
Applies to RootImageOptions=, MountImages= and ExtensionImages=.
Switch from a linked list to an array indexed by the partition
specifier to store them.
Transparent Hugepages (THP) is a Linux kernel feature that manages
memory using larger pages (2MB on x86, compared to the default 4KB).
The main goal is to improve memory management efficiency and system
performance, especially for memory-intensive applications.
However, it can cause drawbacks in some scenarios, such as memory
regression and latency spikes. THP policy is governed for the entire
system via /sys/kernel/mm/transparent_hugepage/enabled.
However, it can be overridden for individual workloads via prctl(2)
call.
MemoryTHP= is used to disable THPs at exec-invoke to stop
providing THPs for workloads where the drawbacks outweigh the advantages.
When set to "disable", MemoryTHP= disables THPs completely for the
process, irrespecitive of global THP controls.
When set to "madvise", MemoryTHP= disables THPs for the process except
when specifically madvised by the process with MADV_HUGEPAGE or MADV_COLLAPSE.
Before doing anything with the root directory file descriptor, let's
make sure we clone it first so that the caller can't mess with mount fd
attributes via mount_setattr() anymore.
We clone during parsing instead of in executor so that the caller can't
mess with the mount fd between invocations.
sys/prctl.h anyway includes linux/prctl.h and actually these .c files
includes sys/prctl.h. Hence, it is not necessary to explicitly include
linux/prctl.h.
This allows a service to reuse the user namespace created for an
existing service, similarly to NetworkNamespacePath=. The configuration
is the initial user namespace (e.g. ID mapping) is preserved.
Let's extract common capability parsing code into a generic function
parse_capability_set() with a comprehensive set of unit tests.
We also replace usages of UINT64_MAX with CAP_MASK_UNSET where
applicable and replace the default value of CapabilityBoundingSet
with CAP_MASK_ALL which more clearly identifies that it is initialized
to all capabilities.
AI (copilot) was used to extract the generic function and write the
unit tests, with manual review and fixing afterwards to make sure
everything was correct.
RootDirectory= but via a open_tree() file descriptor. This allows
setting up the execution environment for a service by the client in
a mount namespace and then starting a transient unit in that execution
environment using the new property.
We also add --root-directory= and --same-root-dir= to systemd-run to
have it run services within the given root directory. As systemd-run
might be invoked from a different mount namespace than what systemd is
running in, systemd-run opens the given path with open_tree() and then
sends it to systemd using the new RootDirectoryFileDescriptor= property.
If socket is used as stdio, we'd currently imply EXEC_PASS_FDS
and dump the whole set of fds to the control processes. This is
pretty much unexpected and unnecessary though, instead let's
pass only the socket fds.
Yes, this is a compat break, but a relatively minor one I'd
argue. And we can always revisit things if users do complain.
The distinction between fdstore and extra fds is only meaningful
to struct Service. As far as executor is concerned they're just
some fds to pass to the service. Let's just merge it hence,
for the sake of simplicity.
Add a new option PrivateBPF= to mount a new instance of bpffs within a
namespace.
PrivateBPF= can be set to "no" to use the host bpffs in readonly mode
and "yes" to do a new mount.
The mount is done with the new fsopen()/fsmount() API because in future
we'll hook some commands between the two calls.
Lennart Poettering
Yu Watanabe
dongshengyuan
Zbigniew Jędrzejewski-Szmek
Luca Boccassi
Michael Vogt
Daan De Meyer
Mike Yuan
Usama Arif
Daan De Meyer
Lennart Poettering
Quentin Deslandes
Ivan Kruglov
Matteo Croce
Andres Beltran