Our baseline glibc is 2.34, which merged libdl, libpthread (the
dependency('threads') target), and librt into libc. Empty .so/.a stubs
remain for backward compatibility with old binaries, but new builds
resolve dl_*, pthread_*, mq_*, timer_*, etc. directly from libc.
On musl the same libraries are likewise empty stubs.
Drop the libdl, threads, and librt entries from every meson.build, and
remove the now-stale 'Libs.private: -lrt -pthread' from libudev.pc.in
since both flags resolve to empty link-time stubs on glibc 2.34+ and
musl.
Verified with readelf -d that libsystemd.so, libudev.so, and systemd no
longer carry DT_NEEDED entries for libdl/libpthread/librt.
test-shift-uid.c doesn't actually use anything from libacl. It all goes
through shared/, and the dep there is enough.
Same for the coredump stuffi, logind and core/.
And pstore doesn't use it at all, neither directly or indirectly.
This commit cleans up the includes for all the small tools across
the tree.
A few cases of returning EXIT_SUCCESS are replaced with returning
0 to avoid including <stdlib.h>.
Split out of #37344.
This means the main config file is loaded also from /run and /usr.
We should load the main config file from all the places where we load drop-ins.
I realize I had a giant blind spot: I always assumed that we load config files
from /etc, /run, /usr/local/lib, /usr/lib. But it turns out that we only used
those paths for drop-ins. For the main config file, we only looked in /etc. The
docs actually partially described this behaviour, i.e. most SYNOPSIS sections
and some parts of the text, but not others.
This is strange, because 6495361c7d was completely
bogus with the behaviour before this patch. We had a huge discussion before it
was merged, and clearly nobody noticed this. Similarly, in the previous version
of the current pull request, we had a long discussion about the appropriate
order of directories, and apparently nobody noticed that there was no order,
because only looked in one directory. So the blind spot seems to have been
shared.
Also, systemd-analyze cat-config behaved incorrectly, i.e. its behaviour matches
the new behaviour.
Possibly, in the future it'll make it easier to add support for --root.
This essentially reverts 5656cdfeea. I find it
much easier to understand what is going on when the
path-relative-to-the-search-path is passed in full, instead of being constructed
from two parts, with one of the parts being implicit in some places.
Also, we call 'systemd-analyze cat-config <path>' with <path> with the same
meaning, so this makes the internal and external APIs more consistent.
Dynamically load liblz4, libzstd and liblzma with dlopen().
This helps to reduce the size of the initrd image when these libraries
are not really needed.
This is preparation for #28891, which adds a bunch more helpers around
"struct iovec", at which point this really deserves its own .c/.h file.
The idea is that we sooner or later can consider "struct iovec" as an
entirely generic mechanism to reference some binary blob, and is the
go-to type for this purpose whenever we need one.
This allows distros to install configuration file templates in /usr/lib/systemd
for example.
Currently we install "empty" config files in /etc/systemd/. They serve two
purposes:
- The file contains commented-out values that show the default settings.
- It is easier to edit the right file if it is already there, the user doesn't
have to type in the path correctly, and the basic file structure is already in
place so it's easier to edit.
Things that have happened since this approach was put in place:
- We started supporting drop-ins for config files, and drop-ins are the
recommended way to create local configuration overrides.
- We have systemd-analyze cat-config which takes care of iterating over
all possible locations (/etc, /run, /usr, /usr/local) and figuring out
the right file.
- Because of the first two points, systemd-analyze cat-config is much better,
because it takes care of finding all the drop-ins and figuring out the
precedence. Looking at files manually is still possible of course, but not
very convenient.
The disadvantages of the current approach with "empty" files in /etc:
- We clutter up /etc so it's harder to see what the local configuration actually is.
- If a user edits the file, package updates will not override the file (e.g.
systemd.rpm uses %config(noreplace). This means that the "documented defaults"
will become stale over time, if the user ever edits the main config file.
Thus, I think that it's reasonable to:
- Install the main config file to /usr/lib so that it serves as reference for
syntax and option names and default values and is properly updated on package
upgrades.
- Recommend to users to always use drop-ins for configuration and
systemd-analyze cat-config to view the documentation.
This setting makes this change opt-in.
Fixes#18420.
[zjs: add more text to the description]
Even with Storage=journal we would still attempt to open the final
dmesg.txt file which causes a lot of noise in the journal:
```
[ 5.764111] H testsuite-82.sh[658]: + systemctl start systemd-pstore
[ 5.806385] H systemd[1]: Starting modprobe@efi_pstore.service...
[ 5.808656] H systemd[1]: modprobe@efi_pstore.service: Deactivated successfully.
[ 5.808971] H systemd[1]: Finished modprobe@efi_pstore.service.
[ 5.818845] H kernel: audit: type=1130 audit(1682630623.637:114): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel msg='unit=modprobe@efi_pstore comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? termin>
[ 5.818865] H kernel: audit: type=1131 audit(1682630623.637:115): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel msg='unit=modprobe@efi_pstore comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? termin>
[ 5.816052] H systemd[1]: Starting systemd-pstore.service...
[ 5.840703] H systemd-pstore[806]: PStore dmesg-efi-168263062313014.
[ 5.841239] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.841428] H systemd-pstore[806]: PStore dmesg-efi-168263062312014.
[ 5.841575] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.841712] H systemd-pstore[806]: PStore dmesg-efi-168263062311014.
[ 5.841839] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.841989] H systemd-pstore[806]: PStore dmesg-efi-168263062310014.
[ 5.842141] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.842274] H systemd-pstore[806]: PStore dmesg-efi-168263062309014.
[ 5.842423] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.842589] H systemd-pstore[806]: PStore dmesg-efi-168263062308014.
[ 5.842722] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.842865] H systemd-pstore[806]: PStore dmesg-efi-168263062307014.
[ 5.843003] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.843153] H systemd-pstore[806]: PStore dmesg-efi-168263062306014.
[ 5.843280] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.843434] H systemd-pstore[806]: PStore dmesg-efi-168263062305014.
[ 5.843570] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.843702] H systemd-pstore[806]: PStore dmesg-efi-168263062304014.
[ 5.843831] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.843958] H systemd-pstore[806]: PStore dmesg-efi-168263062303014.
[ 5.844093] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.844250] H systemd-pstore[806]: PStore dmesg-efi-168263062302014.
[ 5.844412] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.844619] H systemd-pstore[806]: PStore dmesg-efi-168263062301014.
[ 5.844781] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.844956] H systemd-pstore[806]: PStore dmesg-efi-168263062300014.
[ 5.845168] H systemd-pstore[806]: Failed to open file /var/lib/systemd/pstore/1682630623/014/dmesg.txt: Operation not permitted
[ 5.851101] H systemd[1]: Finished systemd-pstore.service.
```
All daemons use a similar scheme to read their main config files and theirs
drop-ins. The main config files are always stored in /etc/systemd directory and
it's easy enough to construct the name of the drop-in directories based on the
name of the main config file.
Hence the new helper does that internally, which allows to reduce and simplify
the args passed previously to config_parse_many_nulstr().
Besides the overall code simplification it results:
16 files changed, 87 insertions(+), 159 deletions(-)
it allows to identify clearly the locations in the code where configuration
files are parsed.
-1 was used everywhere, but -EBADF or -EBADFD started being used in various
places. Let's make things consistent in the new style.
Note that there are two candidates:
EBADF 9 Bad file descriptor
EBADFD 77 File descriptor in bad state
Since we're initializating the fd, we're just assigning a value that means
"no fd yet", so it's just a bad file descriptor, and the first errno fits
better. If instead we had a valid file descriptor that became invalid because
of some operation or state change, the other errno would fit better.
In some places, initialization is dropped if unnecessary.
The approach to use '''…'''.split() instead of a list of strings was initially
used when converting from automake because it allowed identical blocks of lines
to be used for both, making the conversion easier.
But over the years we have been using normal lists more and more, especially
when there were just a few filenames listed. This converts the rest.
No functional change.
We recently started making more use of malloc_usable_size() and rely on
it (see the string_erase() story). Given that we don't really support
sytems where malloc_usable_size() cannot be trusted beyond statistics
anyway, let's go fully in and rework GREEDY_REALLOC() on top of it:
instead of passing around and maintaining the currenly allocated size
everywhere, let's just derive it automatically from
malloc_usable_size().
I am mostly after this for the simplicity this brings. It also brings
minor efficiency improvements I guess, but things become so much nicer
to look at if we can avoid these allocation size variables everywhere.
Note that the malloc_usable_size() man page says relying on it wasn't
"good programming practice", but I think it does this for reasons that
don't apply here: the greedy realloc logic specifically doesn't rely on
the returned extra size, beyond the fact that it is equal or larger than
what was requested.
(This commit was supposed to be a quick patch btw, but apparently we use
the greedy realloc stuff quite a bit across the codebase, so this ends
up touching *a*lot* of code.)
Wherever we read virtual files we better should use
read_full_virtual_file(), to make sure we get a consistent response
given how weird the kernel's handling with partial read on such file
systems is.
As suggested in https://github.com/systemd/systemd/pull/11484#issuecomment-775288617.
This does not touch anything exposed in src/systemd. Changing the defines there
would be a compatibility break.
Note that tests are broken after this commit. They will be fixed in the next one.
By default, systemd installs various sample configuration files
containing commented-out defaults. Systems seeking to minimize the
number of files in /etc may wish to install directories and
configuration files that have semantic effects, but not install not
commented-out sample configuration files.
Turn install-sysconfdir into a multi-valued option, with a "no-samples"
value to skip installing sample-only configuration files.
This is useful for development where overwriting files out side
the configured prefix will affect the host as well as stateless
systems such as NixOS that don't let packages install to /etc but handle
configuration on their own.
Alternative to https://github.com/systemd/systemd/pull/17501
tested with:
$ mkdir inst build && cd build
$ meson \
-Dcreate-log-dirs=false \
-Dsysvrcnd-path=$(realpath ../inst)/etc/rc.d \
-Dsysvinit-path=$(realpath ../inst)/etc/init.d \
-Drootprefix=$(realpath ../inst) \
-Dinstall-sysconfdir=false \
--prefix=$(realpath ../inst) ..
$ ninja install
This is a follow-up for 9f83091e3c.
Instead of reading the mtime off the configuration files after reading,
let's do so before reading, but with the fd we read the data from. This
is not only cleaner (as it allows us to save one stat()), but also has
the benefit that we'll detect changes that happen while we read the
files.
This also reworks unit file drop-ins to use the common code for
determining drop-in mtime, instead of reading system clock for that.
Semmle Security Reports report:
> The problem occurs on the way realloc is being used. When a size
> bigger than the chunk that wants to be reallocated is passed, realloc
> try to malloc a bigger size, however in the case that malloc fails
> (for example, by forcing a big allocation) realloc will return NULL.
>
> According to the man page:
> "The realloc() function returns a pointer to the newly allocated
> memory, which is suitably aligned for any built-in type and may be
> different from ptr, or NULL if the request fails. If size was
> equal to 0, either NULL or a pointer suitable to be passed to free()
> is returned. If realloc() fails, the original block is left
> untouched; it is not freed or moved."
>
> The problem occurs when the memory ptr passed to the first argument of
> realloc is the same as the one used for the result, for example in
> this case:
>
> dmesg = realloc(dmesg, dmesg_size + strlen(pe->dirent.d_name) +
> strlen(":\n") + pe->content_size + 1);
>
> https://lgtm.com/projects/g/systemd/systemd/snapshot/f8bcb81955f9e93a4787627e28f43fffb2a84836/files/src/pstore/pstore.c?sort=name&dir=A
> SC&mode=heatmap#L300
>
> If the malloc inside that realloc fails, then the original memory
> chunk will never be free but since realloc will return NULL, the
> pointer to that memory chunk will be lost and a memory leak will
> occur.
>
> In case you are curious, this is the query we used to find this problem:
> https://lgtm.com/query/8650323308193591473/
Let's use a more standard pattern: allocate memory using greedy_realloc, and
instead of freeing it when we wrote out a chunk, let's just move the cursor
back to the beginning and reuse the memory we allocated previously.
If we fail to allocate the memory for dmesg contents, don't write the dmesg
entry, but let's still process the files to move them out of pstore.
This makes it much easier to debug the program as a normal user, since we
don't need to set up fake input under /sys/fs/pstore/.
Also, let's make the debug output a bit nicer.
Daan De Meyer
Yu Watanabe
Lennart Poettering
Daan De Meyer
Mike Yuan
Zbigniew Jędrzejewski-Szmek
Matteo Croce
Дамјан Георгиевски
Franck Bui
Frantisek Sumsal
Dmitry V. Levin
Eric DeVolder
Jóhann B. Guðmundsson
Josh Triplett
Jörg Thalheim
Michael Olbrich
nikolas