In various tools and services we have a per-system and per-user concept.
So far we sometimes used a boolean indicating whether we are in system
mode, or a reversed boolean indicating whether we are in user mode, or
the LookupScope enum used by the lookup path logic.
Let's address that, in introduce a common enum for this, we can use all
across the board.
This is mostly just search/replace, no actual code changes.
We would resolve those specifiers to the calling user/group. This is mostly OK
when done in the manager, because the manager generally operates as root
in system mode, and a non-root in user mode. It would still be wrong if
called with --test though. But in systemctl, this would be generally wrong,
since we can call 'systemctl --system' as a normal user, either for testing
or even for actual operation with '--root=…'.
When operating in --global mode, %u/%U/%g/%G should return an error.
The information whether we're operating in system mode, user mode, or global
mode is passed as the data pointer to specifier_group_name(), specifier_user_name(),
specifier_group_id(), specifier_user_id(). We can't use userdata, because
it's already used for other things.
This fixes repart's, systemctl's, sysusers' and tmpfiles' specifier
expansion to honour the root dir specified with --root=. This is
relevant for specifiers such as %m, %o, … which are directly sourced
from files on disk.
This doesn't try to be overly smart: specifiers referring to runtime
concepts (i.e. boot ID, architecture, hostname) rather than files on the
medium are left as is. There's certainly a point to be made that they
should fail in case --root= is specified, but I am not entirely convinced
about that, and it's certainly something we can look into later if
there's reason to.
I wondered for a while how to hook this up best, but given that quite a
large number of specifiers resolve to data from files on disks, and most
of our tools needs this, I ultimately decided to make the root dir a
first class parameter to specifier_printf().
Replaces: #16187Fixes: #16183
We usually call specifier_printf() and then check the validity of
the result. In many cases, validity checkers, e.g. path_is_valid(),
refuse too long strings. This makes specifier_printf() refuse such
long results earlier.
Moreover, unit_full_string() and description field in sysuser now
refuse results longer than LONG_LINE_MAX. config_parse() already
refuses the line longer than LONG_LINE_MAX. Hence, it should be ok
to set the same value as the maximum length of the resolved string.
In many cases the tables are largely the same, hence define a common set
of macros to generate the common parts.
This adds in a couple of missing specifiers here and there, so is more
thant just refactoring: it actually fixes accidental omissions.
Note that some entries that look like they could be unified under these
macros can't really be unified, since they are slightly different. For
example in the DNSSD service logic we want to use the DNSSD hostname for
%H rather than the unmodified kernel one.
It's not that I think that "hostname" is vastly superior to "host name". Quite
the opposite — the difference is small, and in some context the two-word version
does fit better. But in the tree, there are ~200 occurrences of the first, and
>1600 of the other, and consistent spelling is more important than any particular
spelling choice.
It would be very wrong if any of the specfier printf calls modified
any of the objects or data being printed. Let's mark all arguments as const
(primarily to make it easier for the reader to see where modifications cannot
occur).
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Those are quite similar to %i/%I, but refer to the last dash-separated
component of the name prefix.
The new functionality of dash-dropins could largely supersede the template
functionality, so it would be tempting to overload %i/%I. But that would
not be backwards compatible. So let's add the two new letters instead.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
The code in install-printf.c and unit-printf.c for these is pretty much
the same and very generic. Let's move this all over to the generic
specifier.c, and share the implementations.
We don't have plural in the name of any other -util files and this
inconsistency trips me up every time I try to type this file name
from memory. "formats-util" is even hard to pronounce.
We should substitute DefaultInstance if the instance is not specified.
Test case:
[Install]
DefaultInstance=bond1
WantedBy= foobar-n-%n.device
WantedBy= foobar-N-%N.device
$ systemctl --root=/ enable testing4@.service
Created symlink /etc/systemd/system/foobar-n-testing4@bond1.service.device.wants/testing4@bond1.service → /etc/systemd/system/testing4@.service.
Created symlink /etc/systemd/system/foobar-N-testing4@bond1.device.wants/testing4@bond1.service → /etc/systemd/system/testing4@.service.
(before, the symlink would be created with empty %n, %N parts).
Previously, the %u, %U, %s and %h specifiers would resolve to the user
name, numeric user ID, shell and home directory of the user configured
in the User= setting of a unit file, or the user of the manager instance
if no User= setting was configured. That at least was the theory. In
real-life this was not ever actually useful:
- For the systemd --user instance it made no sense to ever set User=,
since the instance runs in user context after all, and hence the
privileges to change user IDs don't even exist. The four specifiers
were actually not useful at all in this case.
- For the systemd --system instance we did not allow any resolving that
would require NSS. Hence, %s and %h were not supported, unless
User=root was set, in which case they would be hardcoded to /bin/sh
and /root, to avoid NSS. Then, %u would actually resolve to whatever
was set with User=, but %U would only resolve to the numeric UID of
that setting if the User= was specified in numeric form, or happened
to be root (in which case 0 was hardcoded as mapping). Two of the
specifiers are entirely useless in this case, one is realistically
also useless, and one is pretty pointless.
- Resolving of these settings would only happen if User= was actually
set *before* the specifiers where resolved. This behaviour was
undocumented and is really ugly, as specifiers should actually be
considered something that applies to the whole file equally,
independently of order...
With this change, %u, %U, %s and %h are drastically simplified: they now
always refer to the user that is running the service instance, and the
user configured in the unit file is irrelevant. For the system instance
of systemd this means they always resolve to "root", "0", "/bin/sh" and
"/root", thus avoiding NSS. For the user instance, to the data for the
specific user.
The new behaviour is identical to the old behaviour in all --user cases
and for all units that have no User= set (or set to "0" or "root").
All other types exported from install.h should be namespaces like this,
hence namespace InstallInfo the same way.
Also, remove external forward definition of UnitFileScope type.
A variety of changes:
- Make sure all our calls distuingish OOM from other errors if OOM is
not the only error possible.
- Be much stricter when parsing escaped paths, do not accept trailing or
leading escaped slashes.
- Change unit validation to take a bit mask for allowing plain names,
instance names or template names or an combination thereof.
- Refuse manipulating invalid unit name
This patch removes includes that are not used. The removals were found with
include-what-you-use which checks if any of the symbols from a header is
in use.
Previously the specifier calls could only indicate OOM by returning
NULL. With this change they will return negative errno-style error codes
like everything else.
