This macro emits an SD_ELF_NOTE_DLOPEN note so that calling sites,
and not just libsystemd-shared, get the ELF stamped with the notes
documenting the dependency. Currently most of the dlopen notes end
up in libsystemd-shared, and executables have no way to document
the optional dependencies they need. With this new macro, this
issue can be fixed.
Co-developed-by: Claude Opus 4.8 <noreply@anthropic.com>
Each dlopen_*() wrapper kept its dl handle as a file-scope
'static void *xxx_dl = NULL;' even though only the wrapper itself
ever referenced it. Move each one inside the corresponding function
so its scope matches its actual use, leaving the rest of each
translation unit free of the unused file-scope name.
In pcre2-util.c the assert(pcre2_dl) in pattern_matches_and_log()
becomes assert(sym_pcre2_match), which carries the same invariant
(pattern_compile_and_log() ran dlopen_pcre2()).
Because fdisk_assign_device tries to open block devices with O_EXCL, when it
does it blocks cryptsetup from using partition block devices for the same
disk.
Since we already have a file descriptor for the device, we can just share it
and use fdisk_assign_device_by_fd instead.
This requires at least libfdisk 2.35 (part of util-linux) which was
released in 2020.
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.
Convert fdisk-util to the dlopen pattern used by other optional shared
libraries in libshared. Declare the libfdisk API entry points with
DLSYM_PROTOTYPE, resolve them in a dlopen_fdisk() helper, and call the
sym_* wrappers from the homework, sysupdate and repart binaries that
use them.
With this in place fdisk-util can live in libshared itself, linked only
against libfdisk's headers (via libfdisk_cflags). The libshared_fdisk
convenience library and the libfdisk link dependency on systemd-homework,
systemd-sysupdate, systemd-repart and systemd-repart.standalone go away.
Also add a dlopen_fdisk() check to test-dlopen-so.
Luca Boccassi
Daan De Meyer
Valentin David
Daan De Meyer
Mike Yuan
Lennart Poettering