The BPF kprobe that fires on user namespace destruction is the only
thing
that triggers registry cleanup, so any time it doesn't run — ring buffer
overflow, kprobe missing, fdstore entry dropped outside our cleanup path
— a registry entry is left behind forever.
Stamp each registry entry with the kernel's unique namespace identifier
(NS_GET_ID, kernel ≥ 6.13) at allocation time. At manager startup, after
the existing fdstore→registry sweep, walk the registry and ask the
kernel
to look each namespace up by id via open_by_handle_at() on nsfs; if the
lookup returns -ESTALE the namespace is gone and we release the entry.
Old entries written before this change carry no identifier and are left
alone.
Add a namespace_open_by_id() helper for the lookup. The kernel restricts
open_by_handle_at() on nsfs to processes in the initial user namespace,
collapsing both permission denials and dead namespaces onto -ESTALE; the
helper refuses early with -EPERM outside the initial user namespace
so callers can tell the two apart.
The BPF kprobe that fires on user namespace destruction is the only thing
that triggers registry cleanup, so any time it doesn't run — ring buffer
overflow, kprobe missing, fdstore entry dropped outside our cleanup path
— a registry entry is left behind forever.
Stamp each registry entry with the kernel's unique namespace identifier
(NS_GET_ID, kernel ≥ 6.13) at allocation time. At manager startup, after
the existing fdstore→registry sweep, walk the registry and ask the kernel
to look each namespace up by id via open_by_handle_at() on nsfs; if the
lookup returns -ESTALE the namespace is gone and we release the entry.
Old entries written before this change carry no identifier and are left
alone.
Add a namespace_open_by_id() helper for the lookup. The kernel restricts
open_by_handle_at() on nsfs to processes in the initial user namespace,
collapsing both permission denials and dead namespaces onto -ESTALE; the
helper refuses early with -EHOSTDOWN outside the initial user namespace
so callers can tell the two apart.
For libc syscall wrappers (pidfd_open, fsopen, openat2, etc.) we previously
gated the calls behind build-time HAVE_* checks. Replace these with shim
functions in src/libc/ that fall back to the raw syscall at runtime when the
loaded glibc lacks the symbol. The infrastructure lives in src/libc/libc-shim.h:
DEFINE_SYSCALL_SHIM falls back to a direct syscall, DEFINE_LIBC_SHIM returns
ENOSYS (for posix_spawn-family helpers that have no corresponding syscall), and
DEFINE_LIBC_ERRNO_SHIM sets errno=ENOSYS and returns -1 (for read/write-style
helpers). The weak reference to the libc symbol is bound via __asm__(\"name\")
rename so the bare libc identifier never appears as a C token — this avoids
both #undef boilerplate against override-header redirects and the resulting
-Wredundant-decls warning. Drop the corresponding cc.has_function() loop from
meson.build.
For optional libraries (libcryptsetup, libdw, libarchive), drop the per-symbol
HAVE_* checks. Always declare the prototypes, suppressing the redundant-decl
warnings via DISABLE_WARNING_REDUNDANT_DECLS and NOLINT, and resolve the symbols
after the main dlopen via a new DLSYM_OPTIONAL() helper that only assigns on
success. libcryptsetup's crypt_set_keyring_to_link / crypt_token_set_external_path
and libarchive's *_is_set wrappers use fallback functions as their pointer
initializers (returning -ENOSYS and 0 respectively), so call sites can invoke
the symbol unconditionally and just check for -ENOSYS where the \"not supported\"
distinction matters.
The same shim treatment applies to pidfd_spawn / posix_spawnattr_setcgroup_np
(src/libc/spawn.c) and epoll_pwait2 (src/libc/epoll.c), with corresponding
override headers in src/include/override/spawn.h and
src/include/override/sys/epoll.h. posix_spawn_wrapper() in process-util.c and
epoll_wait_usec() in sd-event.c now detect ENOSYS in the return value instead
of checking the function pointer, falling back to plain posix_spawn() and
epoll_wait() respectively. coredump-config and coredump-submit get a
dlopen_dw_has_dwfl_set_sysroot() helper. The kexec arch gate now uses
defined(__NR_kexec_file_load) directly; pidfd.h uses __has_include_next() to
decide whether to pull in glibc's header.
This lets binaries built against newer glibc / libcryptsetup / libdw /
libarchive headers still load and run on older targets where these symbols are
absent.
This makes __NR_kexec_file_load available on architectures where the kernel
UAPI headers don't define it, matching the runtime fallback path in
src/libc/kexec.c which is gated on #ifdef __NR_kexec_file_load.
systemd now has a system call wrapper that does a long series of #ifdef's to
differentiate between architectures and ABIs. This wrapper has two problems.
1. On mips, it needs to differentiate between O32, N32, N64 ABI. It does that
via a code block in src/include/override/sys/generate-syscall.py (and derived
files):
76 # elif defined(_MIPS_SIM)
77 # if _MIPS_SIM == _MIPS_SIM_ABI32
78 # define systemd_NR_{syscall} {nr_mipso32}
79 # elif _MIPS_SIM == _MIPS_SIM_NABI32
80 # define systemd_NR_{syscall} {nr_mips64n32}
81 # elif _MIPS_SIM == _MIPS_SIM_ABI64
82 # define systemd_NR_{syscall} {nr_mips64}
83 # else
84 # error "Unknown MIPS ABI"
85 # endif
86 # elif defined(__hppa__)
Now the _MIPS_SIM* constants stem from a vendor-specific header file sgidefs.h,
which is included with glibc, but not with musl. It is however always present
in the Linux kernel headers as asm/sgidefs.h ...
2. To work around this, the syscall wrapper already has a block
47 #ifdef ARCH_MIPS
48 #include <asm/sgidefs.h>
49 #endif
Turns out, ARCH_MIPS is defined nowhere in Gentoo, neither on glibc nor on musl.
As a result the code (by accident, probably sgidefs.h is included transitively
somehow) works on glibc, but not on musl.
The simplest fix is to replace line 47 in the generator and the derived file
with
47 #ifdef __mips__
Two other source code files require a similar fix since they rely on the
constants.
Bug: https://github.com/systemd/systemd/issues/41239
Bug: https://bugs.gentoo.org/971376
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
When the extensions for the final system are already set up from the
initrd we should avoid disrupting the boot process with the remount
(which currently isn't atomic) and the daemon reload for
systemd-confext and systemd-sysext. Similarly, when sysupdate ran and
updated extensions it's best to avoid the remount and daemon reload if
no changes are found.
To do this, encode the current extension state in more detail than
before where only the names of the extensions where encoded in the
overlay mount. This can also be used to provide more details about the
extension origin in "systemd-sysext status (--json=)". During the
refresh add a check whether the old state matches the new state and in
this case skip the refresh unless the user provides a flag to always
refresh. Besides the extension name and the resolved path the best
method for identification is the verity hash but that is not available
for plain image files or directories. Therefore, also include data to
check for file/directory replacements. The creation/modification times
are not always real on reproducible images or extracted archive content.
The file handle together with the unique mount ID is the next best
identifier we can use when we have no verity hash. Fall back to an inode
when we get no handle. With the creation/modification time and the path
this should be good enough. Using a unique mount ID is important (with
a fallback to the regular non-unique mount ID) instead of st_dev because
st_dev gets reused too easily, e.g., by a loop device mount and the
mount ID helps to catch this. For the mount ID to be valid it has to be
resolved before we enter the new mount namespace. Thus, it gets provided
by the image dissect logic and handed over to the sysext subprocess
which runs in a new mount namespace.
Luckily, we can rule out online modification of directories or image
files because this is anyway not well supported with overlay mounts, so
we don't do a file checksum nor do we recurse into a directory to look
for the most recently touched files. But, as said, with the
always-refresh flag one can force a reload.
Move the BPF_JMP_A macro from override/linux/bpf.h to
override/linux/bpf_insn.h. The bpf.h override conflicts with libbpf's
-I/usr/include/bpf/uapi include path. Since bpf_insn.h is not typically
installed at /usr/include/linux/ or /usr/include/bpf/uapi/linux/, the
override works without conflicts.
Fixes#40331
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.
libcrypt was no longer built by default since glibc-2.38, and it has been
completely removed since glibc-2.39.
Let's always use libxcrypt, unless when building with musl. As already
major distribution already have libxcrypt-4.4.x, hence let's also bump
the required minimum version to 4.4.0.
libxcrypt cannot be built with musl, hence the previous fallback logic
in libcrypt-util.c are moved to musl/crypt.c.
Note, libxcrypt-4.4.0 was released on 2018-11-20.
See also #38608.
Allow CPUSchedulingPolicy to be set to "ext". SCHED_EXT is a new
scheduling policy in Linux v6.12 that allows processes to be scheduled
using custom BPF schedulers instead of the default in-kernel ones.
Selectively setting the SCHED_EXT policy is useful for systems running
in "partial mode" where not all processes are run using a custom
scheduler.
Fallback to SCHED_OTHER and print an error message for systems where
SCHED_EXT isn't available.
musl's getopt_long() behaves something different in handling optional arguments:
```
$ journalctl _PID=1 _COMM=systemd --since 19:19:01 -n all --follow
Failed to add match 'all': Invalid argument
```
This introduces getopt_long_fix() that reorders the passed arguments to make
getopt_long() provided by musl works as what we expect.
Also, musl's getopt() always behaves POSIXLY_CORRECT mode, and stops parsing
arguments when a non-option string found. Let's always use getopt_long().
This reverts commit 3ae7d8fd87.
Now utmp support is always disabled when building with musl,
and all definitions are unused in that case. Let's remove it.
musl neither support GLOB_ALTDIRFUNC nor GLOB_BRACE.
Let's make safe_glob() work even when GLOB_ALTDIRFUNC is not supported.
Currently, GLOB_BRACE is simply ignored when it is not supported.
musl provides XSI compliant strerror_r(), and it is slightly different
from the one by glibc.
Let's introduce a tiny wrapper to convert XSI strerror_r() to GNU one.
The wrapper also patches musl's spurious catchall error message.
glibc's sys/stat.h includes linux/stat.h, and we have copy of it from
the latest kernel, hence all new flags are always defined.
However, musl's sys/stat.h does not include linux/stat.h, and moreover,
they conflict with each other, hence we cannot include both header
simultaneously. Let's define missing macros to support musl.
This is to avoid build failures like below for musl.
test-recurse-dir.c:23:24: error: ‘FTW_CONTINUE’ undeclared
Co-authored-by: Yu Watanabe <watanabe.yu+github@gmail.com>
Even 'gshadow' meson option is disabled, src/shared/userdb.c and
src/shared/user-record-nss.c include gshadow.h unconditionally.
Let's introduce dummy header to make them compiled gracefully.
Yu Watanabe
Zbigniew Jędrzejewski-Szmek
Daan De Meyer
Luca Boccassi
Andreas K. Hüttel
Mike Yuan
Kai Lueke
calm329
Usama Arif
Matt Fleming
Daan De Meyer
Luca Boccassi
Emil Renner BerthingandYu Watanabe
Chen QiandYu Watanabe