sysctl-util: minimize side-effects when running `systemd-sysctl`
Currently `systemd-sysctl` binary is used in `systemd-sysctl.service`
which is mostly configured as `oneshot`. There are situations where one
would like to use systemd to maintain Sysctl configurations on a host,
using a configuration managers such as Chef or Puppet, by apply
configurations every X duration.
The problem with using `systemd-sysctl` is that it writes all the Sysctl
settings, even if the values for those settings have not changed. From
experience, we have observed that some Sysctl settings cause actions in
the kernel upon writing(like dropping caches) which in turn cause
undesired side effects.
This patch tries to minimize such side effects by comparing values
before writing.
tree-wide: make format_ifname() or friends return negative errno on failure
Also,
- drop unnecessary +1 from buffer size, as IF_NAMESIZE or IFNAMSIZ
includes the nul at the end.
- format_ifname() does not update buffer on failure,
- introduces format_ifname_alloc(), FORMAT_IFNAME(), and their friends.
dissect-image: optionally, validate dm-verity signatures in userspace
Getting certificates for dm-verity roothash signing into the trusted
kernel keychain is a royal PITA (means recompiling or rebooting with
shim), hence let's add a minimal userspace PKCS7 validation as well.
The mechanism is really simple and compatible with the verification the
kernel does. The only difference is that the certificates are searched
in /etc/verity.d/*.crt (and similar dirs in /usr/lib/, …).
We'll first try validation by passing the PKCS#7 data to the kernel, but
if that doesn't work we'll see if one of the certificates found that way
works and then attempt to attach the image without passing the PKCS#7
data to the kernel.
This makes it very easy to have fully validated GPT disk images. For
example, just copy the 'mkosi.secure-boot.crt' file you have in your
mkosi build dir to /etc/verity.d/ and things should just work.
cryptsetup: handle more gracefully if "keyslots" LUKS2 JSON header field is invalid
The field is not owned by us (even though is in our JSON objects) but by
the LUKS2 spec. Hence let's handle this a bit more gracefully: let's not
get confused by it, just warn and skip over it.
core: Add ExecSearchPath parameter to specify the directory relative to which binaries executed by Exec*= should be found
Currently there does not exist a way to specify a path relative to which
all binaries executed by Exec should be found. The only way is to
specify the absolute path.
This change implements the functionality to specify a path relative to which
binaries executed by Exec*= can be found.
meson: allow extra net naming schemes to be defined during configuration
In upstream, we have a linearly-growing list of net-naming-scheme defines;
we add a new one for every release where we make user-visible changes to the
naming scheme.
But the general idea was that downstream distributions could define their
own combinations (or even just their own names for existing combinations),
so provide stability for their users. So far this required patching of the
netif-naming-scheme.c and .h files to add the new lines.
The syntax is a comma-separated list of NAME=name+name+…
This syntax is a bit scary, but any typos result in compilation errors,
so I think it should be OK in practice.
With this approach, we don't allow users to define arbitrary combinations:
what is allowed is still defined at compilation time, so it's up to the
distribution maintainers to provide reasonable combinations. In this regard,
the only difference from status quo is that it's much easier to do (and harder
to do incorrectly, for example by forgetting to add a name to one of the
maps).
We used 'combo' type for the scheme list. For a while we forgot to add
new names, and recently aa0a23ec86 added v241, v243, v245, and v247.
I want to allow defining new values during configuration, which means
that we can't use meson to verify the list of options. So any value is
allowed, but then two tests are added: one that will fail compilation if some
invalid name is given (other than "latest"), and one that converts
DEFAULT_NET_NAMING_SCHEME to a NamingScheme pointer.
It seems some of the tests break network connectivity on the host,
as the code coverage upload fails to establish a connection.
Run them in a network namespace with 'unshare -n'.
man: mention pages with more settings at end of each option list
For some unit types we have hundreds of options, and the reader may easily miss
that more options are described in other pages. We already mentioned this in
the introduction and then at the top of the option list, but it can't hurt to
repeat the information.
Also, add an (almost empty) Options section for the unit types which don't have
any custom options. It is nicer to have the same page structure in all cases,
so people can jump between pages for different types more easily.
I have no idea if this is going to cause rendering problems, and it is fairly
hard to check. So let's just merge this, and if it github markdown processor
doesn't like it, revert.
man: cross-reference DeviceAllow= and PrivateDevices=
They are somewhat similar, but not easy to discover, esp. considering that
they are described in different pages.
For PrivateDevices=, split out the first paragraph that gives the high-level
overview. (The giant second paragraph could also use some heavy editing to break
it up into more digestible chunks, alas.)
Before:
```
Compiling C object src/libsystemd-network/libsystemd-network.a.p/dhcp6-option.c.o
../src/libsystemd-network/dhcp6-option.c: In function ‘dhcp6_option_parse_ia’:
../src/libsystemd-network/dhcp6-option.c:633:70: warning: passing argument 3 of ‘dhcp6_option_parse’ makes pointer from integer without a cast [-Wint-conversion]
633 | r = dhcp6_option_parse(option_data, option_data_len, offset, &subopt, &subdata_len, &subdata);
| ^~~~~~
| |
| size_t {aka long unsigned int}
../src/libsystemd-network/dhcp6-option.c:358:25: note: expected ‘size_t *’ {aka ‘long unsigned int *’} but argument is of type ‘size_t’ {aka ‘long unsigned int’}
358 | size_t *offset,
| ~~~~~~~~^~~~~~
```
After:
```
../src/libsystemd-network/dhcp6-option.c: In function ‘dhcp6_option_parse_ia’:
../src/libsystemd-network/dhcp6-option.c:633:70: error: passing argument 3 of ‘dhcp6_option_parse’ makes pointer from integer without a cast [-Werror=int-conversion]
633 | r = dhcp6_option_parse(option_data, option_data_len, offset, &subopt, &subdata_len, &subdata);
| ^~~~~~
| |
| size_t {aka long unsigned int}
../src/libsystemd-network/dhcp6-option.c:358:25: note: expected ‘size_t *’ {aka ‘long unsigned int *’} but argument is of type ‘size_t’ {aka ‘long unsigned int’}
358 | size_t *offset,
| ~~~~~~~~^~~~~~
cc1: some warnings being treated as errors
```
loadavg.h is an internal header of the Linux source repository, and as
such it is licensed as GPLv2-only, without syscall exception.
We use it only for 4 macros, which are simply doing some math calculations
that cannot thus be subject to copyright.
Reimplement the same calculations in another internal header and delete
loadavg.h from our tree.