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.
We often have a pattern where the same verb function is used for
multiple actions. This leads to an antipattern where we figure out what
action needs to be taken from argv[0] multiple times: often once in
parse_argv() to figure out what options are allowed, then once again
implicitly in dispatch_verb(), and then again in the action verb itself.
Let's allow passing a parameter into the verb to simplify this.
This matches a pattern we have in conf-parser.h, where we have both
void *userdata (more global) and void *data (per-config item). Here,
I opted for uintptr_t userdata. It seems that most of the time we'll
want to just pass an enum value. This works OK with no casts. I also
tried a void* and union. In both cases, much more boilerplate is needed:
either a cast or a macro to help avoid compiler warnings. uintptr_t
seems generic enough to cover foreseeable usecases with no fuss.
This is a noop refactoring. See next commit for an example.
Historically, resolvectl status has not included the interface
specification for DNS servers with an IPv6 link-local address, since it
is technically somewhat redundant. But, adding this extra bit of
information makes it easier to copy-and-paste to use elsewhere, etc.
For example, the previous output:
Link 2 (enp34s0)
Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
Protocols: +DefaultRoute LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: fe80::861e:a3ff:feb1:f8e7
DNS Servers: 192.168.1.12 192.168.1.13 fe80::861e:a3ff:feb1:f8e7
DNS Domain: lan
now becomes:
Link 2 (enp34s0)
Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
Protocols: +DefaultRoute LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: fe80::861e:a3ff:feb1:f8e7%2
DNS Servers: 192.168.1.12 192.168.1.13 fe80::861e:a3ff:feb1:f8e7%2
DNS Domain: lan
There is a lot of duplication across the functions for printing global,
link, and delegate output. Since these all use a common DNSConfiguration
type now, the logic can be consolidated.
Adapt printing and format helper functions to accept a DNSConfiguration
parameter to appropriately format output. Then, add print_configuration(),
a single function that prints the appropriate status output based on the
contents of DNSConfiguration.
Now that varlink is always used for status output, consolidate the JSON
and regular status code paths. Add status_full(), which is the single
point that calls DumpDNSConfiguration, filters based on link names and
mode if needed, and prints the output in the appropriate format.
This simplifies status_ifindex(), and removes the need for a separate
status_json().
This is an incremental commit to replacing dbus usage with varlink for
all status output.
Re-implement regular delegate status output using the DumpDNSConfiguration
varlink method. And, remove the DelegateInfo type and associated functions
which were used to map dbus properties.
Since this is the last type of status output to be switched to varlink,
lots of other code becomes dead with these changes, e.g.
read_dns_server_one(), map_dns_servers_internal(), etc., so remove those
too. Finally, status_all() no longer needs sd_bus, so drop that
parameter.
This is an incremental commit to replacing dbus usage with varlink for
all status output.
Re-implement regular link status output using the DumpDNSConfiguration
varlink method. And, remove the LinkInfo type and associated functions
which were used to map dbus properties.
This is an incremental commit to replacing dbus usage with varlink for
all status output.
Re-implement regular global status output using the DumpDNSConfiguration
varlink method. And, remove the GlobalInfo type and associated functions
which were used to map dbus properties.
This introduces /run/systemd/resolve.hook/ as a new directory that local
(privileged) programs can bind a Varlink socket into. If they do they'll
get a method call for each attempted resolved lookup, which they can
then either process themselves (and generate new records for, or return
errors to block stuff) or let pass so that the regular resolution is
done.
Usecase for this is primarily two things:
1. in machined we can add local resolution of machine names to their IP
addresses, similar in fashion to nss-mymachines, but working also if
the non-NSS interfaces to name resolution are used, i.e. the local
DNS responder. In fact, I think we should eventually remove
nss-mymachines from our tree, as soon as this code in resolved is
setlled.
2. in networkd we can add local resolution of names specified in DHCP
leases we hand out.
But beyond that there should be many other uses, for example people
could write "dns firewalls" with this if they like where they
dynamically block certain names from resolution.
Fixes: #8518
We want to reuse these generic DNS concepts in resolved hook
implementations, hence move them to shared code.
(This also enables us to immediately remove som SVCB record handling
duplicate definitions.)
No real code changes, just some moving around of things.
We had errno_to_name() which works for "known" errnos, and returns NULL for
unknown ones, and then ERRNO_NAME which always returns an answer, possibly just
a number as a string, but requires a helper buffer.
It is possible for the kernel to add a new errno. We recently learned that some
architectures define custom errno names. Or for some function to unexpectedly
return a bogus errno value. In almost all cases it's better to print that value
rather than "n/a" or "(null)". So let's use ERRNO_NAME is most error handling
code. Noteably, our code wasn't very good in handling the potential NULL, so
in various places we could print "(null)". Since this is supposed to be used
most of the time, let's shorten the names to ERRNO_NAME/errno_name.
There are a few places where we don't want to use the fallback path, in
particular for D-Bus error names or when saving the error name. Let's rename
errno_to_name() to errno_name_no_fallback() to make the distinction clearer.
Let's also show A/AAAA data in binary form if --raw=payload is used. For
these RR types there's only a single data field, hence it's obbviously
meant.
Inspired by: #37737
Let's handle the per-link and the global dns server/search domain
property parsing the same. Let's use a flags field for three separate
booleans, and unify more code.
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.
Previous code assumed that both family and address are read when
-EINVAL, hence the following read of port and name could succeed.
Let's drop the assumption, and skip reading remaining elements.
No functional change, just refactoring and preparation for later change.
Admittedly, some of our glyphs _are_ special, e.g. "O=" for SPECIAL_GLYPH_TOUCH ;)
But we don't need this in the name. The very long names make some invocations
very wordy, e.g. special_glyph(SPECIAL_GLYPH_SLIGHTLY_UNHAPPY_SMILEY).
Also, I want to add GLYPH_SPACE, which is not special at all.
We often used a pattern like if (!FLAGS_SET(flags, SD_JSON_FORMAT_OFF)),
which is rather verbose and also contains a double negative, which we try
to avoid. Add a little helper to avoid an explicit bit check.
This change clarifies an aditional thing: in some cases we treated
SD_JSON_FORMAT_OFF as a flag (flags & SD_JSON_FORMAT_OFF), while in other cases
we treated it as an independent enum value (flags == SD_JSON_FORMAT_OFF).
In the first form, flags like SD_JSON_FORMAT_SSE do _not_ turn the json
output on, while in the second form they do. Let's use the first form
everywhere.
No functional change intended.
Initially I wasn't sure if this helper should be made public or just internal,
but it seems such a common pattern that if we expose the flags, we might just
as well expose it too, to make life easier for any consumers.
Zbigniew Jędrzejewski-Szmek
Nick Rosbrook
Yu Watanabe
Lennart Poettering
Antonio Alvarez Feijoo
Zbigniew Jędrzejewski-Szmek
DaanDeMeyer