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
I am really not a fan of full code lines passed to macros as parameters.
Let's get rid of the 3rd parameter of FOREACH_OPTION() hence:
1. Let's return errors just as a regular value (though a negative one),
that can be handled via a OPTION_ERROR case statement for the switch.
This normalizes handling of the error, just like any other event
returned by the option parser.
2. In order to avoid exploding the amount of boilerplate in each use
(that just propagates the error on OPTION_ERROR), let's then
introduce an explicit FOREACH_OPTION_OR_RETURN(), that returns from
the calling function on its own (and makes that clear in the name).
Together this cleans up, normalizes the logic and shortens the code.
It was requested to make the 'c', 'opt', and 'arg' params the same, i.e.
defined through the FOREACH_OPTION macro. But we can't do that easily,
because 'c' was defined in the for loop definition, and we can only
define variables of the same type in that way. Also, in some cases we
need only 'c', in other cases with need 'c' and 'arg, in some cases 'c'
and 'opt', and in other cases all three. We'd need to either
conditionalize or mark those variables with _unused_ to deal with
compiler warnings. But a different approach works quite nicely: add
state.opt and state.arg to show the current option and it's argument.
(The short names are picked on purpose to reduce verbosity since those
are used a lot.)
We generally want to print an error message if table_print()
fails. Add a helper function for this and use it consistently.
This does one of the three things depending on the call site:
- a no-change reformatting of the code
- change from a custom message to the generic one
- addition of the error message where previously none was printed
In the third case, the actual use impact is very small, since the
table formatting is very unlikely to fail. But if it did, we would
often return an error without any message whatsoever, which we
never want to do.
Almost all callers of table_print() specify stdout or NULL (equivalent
to stdout) as the output stream. Simplify things by not requiring the
the stream to be specified.
In almost all cases, the printing of the table is surrounded by normal
printfs() that don't do explicit flushing and for which we don't check
the output stream status. Let's simplify most callers and skip this
step. The reason is not so much to avoid the extra step itself, but
instead to avoid the _handling_ of the potential failure. We generally
only want to print an error message for ENOMEM and other "internal"
errors, so strictly speaking we should filter out the errors from the
stream. By skipping the flush&check step we implicitly do this.
After writing the code to parse options in a bunch of places, I think
passing the argc+argv to various functions to query state is annoying.
It seems nicer to just stash them in the state struct once.
Old gcc (<14) says:
2026-03-02T23:11:28.5676353Z In file included from ../src/notify/notify.c:30:
2026-03-02T23:11:28.5694607Z In function ‘strv_isempty’,
2026-03-02T23:11:28.5695481Z inlined from ‘action_fork’ at ../src/notify/notify.c:440:9,
2026-03-02T23:11:28.5696266Z inlined from ‘run’ at ../src/notify/notify.c:541:24,
2026-03-02T23:11:28.5696929Z inlined from ‘main’ at ../src/notify/notify.c:682:1:
2026-03-02T23:11:28.5697877Z ../src/basic/strv.h:108:23: error: ‘args’ may be used uninitialized [-Werror=maybe-uninitialized]
2026-03-02T23:11:28.5698655Z 108 | return !l || !*l;
2026-03-02T23:11:28.5699052Z | ^~
2026-03-02T23:11:28.5700020Z ../src/notify/notify.c: In function ‘main’:
2026-03-02T23:11:28.5700681Z ../src/notify/notify.c:531:16: note: ‘args’ was declared here
2026-03-02T23:11:28.5701217Z 531 | char **args;
2026-03-02T23:11:28.5701574Z | ^~~~
2026-03-02T23:11:28.5701960Z cc1: all warnings being treated as errors
Now that sd-event doesn't insist on blocking
SIGCHLD anymore when watching for process exit,
let's stop blocking SIGCHLD tree-wide where not
required anymore.
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.
Let's move some logic from _DEFINE_MAIN_FUNCTION() and other places
in main-func.h into functions that we implement in main-func.c to
allow moving some included headers from the header to the .c file.
Follow-up for 7f6af95dab
- Allocate internal buf on the stack, memdup() only at the end.
This ensures we're able to handle OOM gracefully, i.e.
return -EAGAIN on OOM while still emptying socket buffer.
- Do not treat empty notify message as error.
- Raise log level since all callers log loudly anyway.
The previous commit removed the UINT_MAX check for the fd array. Let's
now re-add one, but at a better place, and with a more useful limit. As
it turns out the kernel does not allow passing more than 253 fds at the
same time, hence use that as limit. And do so immediately before
calculating the control buffer size, so that we catch multiplication
overflows.
Before this commit, if --exec is used but no message shall
be sent, we silently ignore --exec and exit, which is pretty
surprising. Therefore, let's emit clear error instead.
So here's the thing. One library we use (libselinux) is opening fds
behind our back when we initialize it and keeps it open. On the other
hand we want to automatically pick up all fds passed in to us, so that
we can distribute them to our services and close the rest. We pick them
up very early in our code, to ensure that we don't get confused by open
fds at that point. Except that libselinux insists on being initialized
even earlier. So suddenly we might take possession of libselinux' fds,
and then close them later when we decide no service wants them. Then
during shutdown we close down selinux and selinux closes its fds, but
since already closed long ago this ight close our fds instead. Hilarity
ensues.
I wish low-level software wouldn't do such things behind our back, but
well, let's make the best of it.
This changes the fd pick-up logic to only pick up fds that have
O_CLOEXEC unset. O_CLOEXEC must be unset for any fds passed in to us
over execve() after all. And for all our own fds we should set O_CLOEXEC
since we generally don't want to litter fd tables for execve(). Also,
libselinux thankfully appears to set O_CLOEXEC correctly on its fds,
hence the filter works.
Fixes: #27491
The previous error code -ERANGE is slightly ambiguous, and use more
specific one. This also drops unnecessary error handlings.
Follow-up for 754d8b9c33 and
e652663a04.
In 623a00020f code was added that our
various programs send a notification message with their exit status on
exit. This is great, but it becomes utterly confusing in systemd-notify,
whose primary purpose is to send such messages after all, and sending an
implicit one in addition to the primary one is particularly confusing,
when debugging things.
Let's hence just drop the implicit message. systemd-notify's exit status
is after all indicative primarily because sd_notify() failed, and hence
it's pretty pointless to then send that fact as another sd_notify()
message.
(Primary reason for this patch is simply that it confused the hell out
of me, when debugging sd_notify() issues)
Follow-up for: 623a00020f
These wrap RELOADING=1 and STOPPING=1 messages. The former is
particularly useful, since we want to insert the MONOTONIC_USEC= field
into the message automatically, which is easy from C but harder from
shell.
In general we almost never hit those asserts in production code, so users see
them very rarely, if ever. But either way, we just need something that users
can pass to the developers.
We have quite a few of those asserts, and some have fairly nice messages, but
many are like "WTF?" or "???" or "unexpected something". The error that is
printed includes the file location, and function name. In almost all functions
there's at most one assert, so the function name alone is enough to identify
the failure for a developer. So we don't get much extra from the message, and
we might just as well drop them.
Dropping them makes our code a tiny bit smaller, and most importantly, improves
development experience by making it easy to insert such an assert in the code
without thinking how to phrase the argument.
I think this formatting was originally used because it simplified
adding new options to the help messages. However, these days, most
tools their help message end with "\nSee the %s for details.\n" so
the final line almost never has to be edited which eliminates the
benefit of the custom formatting used for printf() help messages.
Let's make things more consistent and use the same formatting for
printf() help messages that we use everywhere else.
Prompted by https://github.com/systemd/systemd/pull/18355#discussion_r567241580
Zbigniew Jędrzejewski-Szmek
Lennart Poettering
Daan De Meyer
Mike Yuan
Lennart Poettering
Yu Watanabe
David Tardon
Zbigniew Jędrzejewski-Szmek
Joerg Behrmann