When the .so module is loaded, it gets a separate copy of stuff in src/basic,
including the log level variables. So any logging settings are unaffected by
the loading program calling log_parse_environment() or such. Let's also parse
the environment here so that we can have nice logging.
Initialization is done from each exported function, and pthread_once_t is used
to avoid duplicate initialization. I didn't merge PROTECT_ERRNO into
NSS_ENTRYPOINT_BEGIN because UNPROTECT_ERRNO is called in a bunch of places
and it would feel strange to have PROTECT_ERRNO hidden, but not UNPROTECT_ERRNO.
The most interesting stuff in this module is the varlink messages, and any
potential errors in json. So let's enable json logging when debug messages are
enabled.
With those changes, figuring out the issue in
https://github.com/systemd/systemd/pull/17823 is trivial:
$ LD_LIBRARY_PATH=build/ SYSTEMD_LOG_COLOR=1 SYSTEMD_LOG_LOCATION=1 SYSTEMD_LOG_LEVEL=debug getent hosts mirrors.fedoraproject.org
src/shared/varlink.c:237: n/a: varlink: setting state idle-client
src/shared/varlink.c:1240: n/a: Sending message: {"method":"io.systemd.Resolve.ResolveHostname","parameters":{"name":"mirrors.fedoraproject.org","family":10}}
src/shared/varlink.c:240: n/a: varlink: changing state idle-client → calling
src/shared/varlink.c:588: n/a: New incoming message: {"parameters":{"addresses":[{"ifindex":0,"family":10,"address":[42,5,208,20,0,16,120,3,247,116,77,124,226,119,164,87]},{"ifindex":0,"family":10,"address":[42,5,208,28,12,106,204,3,38,58,132,9,185,97,126,2]},{"ifindex":0,"family":10,"address":[38,32,0,82,0,3,0,1,222,173,190,239,202,254,254,215]},{"ifindex":0,"family":10,"address":[38,5,188,128,48,16,6,0,222,173,190,239,202,254,254,217]},{"ifindex":0,"family":10,"address":[38,4,21,128,254,0,0,0,222,173,190,239,202,254,254,209]},{"ifindex":0,"family":10,"address":[38,32,0,82,0,3,0,1,222,173,190,239,202,254,254,214]},{"ifindex":0,"family":10,"address":[38,16,0,40,48,144,48,1,222,173,190,239,202,254,254,211]},{"ifindex":0,"family":10,"address":[32,1,65,120,0,2,18,105,0,0,0,0,0,0,254,210]}],"name":"wildcard.fedoraproject.org","flags":1}}
src/shared/varlink.c:240: n/a: varlink: changing state calling → called
src/shared/varlink.c:240: n/a: varlink: changing state called → idle-client
src/nss-resolve/nss-resolve.c:84: (string):1:40: JSON field 'ifindex' is out of bounds for an interface index.
This reverts commit b26c904113.
I don't see anythign wrong, but Ubuntu autopkgtest CI started failing fairly
consistently since this was merged. Let's see if reverting fixes things.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
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.
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.
DNS queries have a timeout of DNS_TRANSACTION_ATTEMPTS_MAX *
DNS_TIMEOUT_MAX_USEC = 120 s. Calls to the ResolveHostname method of
the org.freedesktop.resolve1.Manager interface have various call
timeouts that are smaller than 120 s. So it seems correct to adjust
the call timeout to the maximum query timeout and to unify the call
timeout among all callers.
A timeout of 120 s might seem large, in particular since BIND does seem
to have a query timeout of 10 s. However, it seems match the timeout
value of 120 s of Unbound. Moreover, the query and timeout handling of
resolve have problems and might be improved in the future, so this
change is at best an interim solution.
If we could not communicate with systemd-resolved, we would call into
libnss_dns. libnss_dns would return NOTFOUND for stuff like "localhost" and
other names resolved by nss-myhostname, which we would fall under the !UNAVAIL=
condition and cause resolution to fail. So the following recommended
configuration in nsswitch.conf would not work:
hosts: resolve [!UNAVAIL=return] dns myhostname
Remove the internal fallback code completely so that the fallback logic
can be configured in nsswitch.conf.
Tested with
hosts: resolve [!UNAVAIL=return] myhostname
and
hosts: resolve [!UNAVAIL=return] dns myhostname
Fixes#5742.
The correct error code to report when a provided buffer is too small is
ERANGE. This is recognized by glibc, which will then try again with a
larger buffer. The old behaviour of reporting ENOMEM has no special
meaning for glibc. The error will simply be propagated to the
application, and a later retry will trigger the same error again.
Additionally, h_errnop must be set to NETDB_INTERNAL to have glibc look
at errnop for details.
More information at:
https://www.gnu.org/software/libc/manual/html_node/NSS-Modules-Interface.html
Let's tighten the cases when our module returns NSS_STATUS_NOTFOUND. Let's do
so only if we actually managed to talk to resolved. In all other cases stick to
NSS_STATUS_UNAVAIL as before, as it clearly indicates that our module or the
system is borked, and the "dns" fallback should really take place.
In particular this fixes the 2nd-level fallback from our own dlopen() based
fallback handling. In this case we really should return UNAVAIL so that the
caller can apply its own fallback still.
Fix-up for d7247512a9.
Note that our own dlopen() based fallback is pretty much redundant now if
nsswitch.conf is configured like this:
hosts: files mymachines resolve [!UNAVAIL=return] dns myhostname
In a future release we should probably drop our internal fallback then, in
favour of this nsswitch.conf-based one.
It needs to be possible to tell apart "the nss-resolve module does not exist"
(which can happen when running foreign-architecture programs) from "the queried
DNS name failed DNSSEC validation" or other errors. So return NOTFOUND for these
cases too, and only keep UNAVAIL for the cases where we cannot handle the given
address family.
This makes it possible to configure a fallback to "dns" without breaking
DNSSEC, with "resolve [!UNAVAIL=return] dns". Add this to the manpage.
This does not change behaviour if resolved is not running, as that already
falls back to the "dns" glibc module.
Fixes#4157
Handle general errors from the resolved call in _nss_resolve_gethostbyaddr2_r()
the same say as in the other variants: Just "goto fail" as that does exactly
the same.
Throughout the tree there's spurious use of spaces separating ++ and --
operators from their respective operands. Make ++ and -- operator
consistent with the majority of existing uses; discard the spaces.
Let's make sure our poll() calls don't get interrupted where they shouldn't (SIGALRM, ...), but allow them to be
interrupted where they should (SIGINT, ...).
Fixes#1965
GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
With this change we'll now also generate synthesized RRs for the local
LLMNR hostname (first label of system hostname), the local mDNS hostname
(first label of system hostname suffixed with .local), the "gateway"
hostname and all the reverse PTRs. This hence takes over part of what
nss-myhostname already implemented.
Local hostnames resolve to the set of local IP addresses. Since the
addresses are possibly on different interfaces it is necessary to change
the internal DnsAnswer object to track per-RR interface indexes, and to
change the bus API to always return the interface per-address rather than
per-reply. This change also patches the existing clients for resolved
accordingly (nss-resolve + systemd-resolve-host).
This also changes the routing logic for queries slightly: we now ensure
that the local hostname is never resolved via LLMNR, thus making it
trustable on the local system.
sd_bus_flush_close_unref() is a call that simply combines sd_bus_flush()
(which writes all unwritten messages out) + sd_bus_close() (which
terminates the connection, releasing all unread messages) +
sd_bus_unref() (which frees the connection).
The combination of this call is used pretty frequently in systemd tools
right before exiting, and should also be relevant for most external
clients, and is hence useful to cover in a call of its own.
Previously the combination of the three calls was already done in the
_cleanup_bus_close_unref_ macro, but this was only available internally.
Also see #327
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.
Zbigniew Jędrzejewski-Szmek