The levels have an order, but the order is sometimes a bit arbitrary.
Hence add simple macros to check for specific features and use those, so
that the ordering leaks a bit less into all files.
So far we didn't really handle the case where we can't parse a reply
packet. Since this apparently happens in real-life though, let's add
some minimal logic, to downgrade/restart if we see this.
With all the preparatory work in previous PRs, we can now call static destructors
repeatedly without issue. We need to do it here so that global variables allocated
during parsing are properly freed.
If the cleanup function returns the appropriate type, use that to reset the
variable. For other functions (usually the foreign ones which return void), add
an explicit value to reset to.
This causes a bit of code churn, but I think it might be worth it. In a
following patch static destructors will be called from a fuzzer, and this
change allows them to be called multiple times. But I think such a change might
help with detecting unitialized code reuse too. We hit various bugs like this,
and things are more obvious when a pointer has been set to NULL.
I was worried whether this change increases text size, but it doesn't seem to:
-Dbuildtype=debug:
before "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494520 Feb 16 15:06 build/systemd*
after "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494576 Feb 16 15:10 build/systemd*
now:
-rwxrwxr-x 1 zbyszek zbyszek 4117672 Feb 16 14:36 build/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 4494640 Feb 16 15:15 build/systemd*
-Dbuildtype=release:
before "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:09 build-rawhide/systemd*
after "tree-wide: return NULL from freeing functions":
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:10 build-rawhide/systemd*
now:
-rwxrwxr-x 1 zbyszek zbyszek 5252256 Feb 14 14:47 build-rawhide/libsystemd.so.0.30.0*
-rwxrwxr-x 1 zbyszek zbyszek 1834184 Feb 16 15:16 build-rawhide/systemd*
I would expect that the compiler would be able to elide the setting of a
variable if the variable is never used again. And this seems to be the case:
in optimized builds there is no change in size whatsoever. And the change in
size in unoptimized build is negligible.
Something strange is happening with size of libsystemd: it's bigger in
optimized builds. Something to figure out, but unrelated to this patch.
I started working on this because I wanted to change how
DEFINE_TRIVIAL_CLEANUP_FUNC is defined. Even independently of that change, it's
nice to make make things more consistent and predictable.
Let's preferably route traffic for reverse lookups to LLMNR/mDNS/DNS on
the matching interface if the IP address is in the local subnet. Also,
if looking up an IP address of our own host, let's avoid doing
LLMNR/mDNS at all.
This is useful if "~." is a routing domain to DNS, as it means, local
reverse lookups still go to LLMNR/mDNS, too.
Fixes: #16243#10081
All callers of strv_env_replace() would free the argument on error.
So let's follow the same pattern as with strv_consume (and similar
naming) and unconditionally "use up" the argument.
Some paths (eg: mount_tmpfs) simply assumed that prefixing always
happens and it always stores the original path in path_const, and
the prefixed path in path_malloc.
But if a MountEntry is set up in a helper function and thus uses
only _malloc struct members, this assumption doesn't hold and there's
a crash.
Refactor so that prefixing is done with a helper which stores the
original path in a separate struct member, and accessing it also
uses a helper which does the right thing.
_gc() does cleanup if it is possible. So far it returned a bool to
signal if it succeeded (false on success). When working on the resolved
code I had to look at the definition every time, because the (arguably
reversed) calling convention is unobvious. So let's return a pointer
(non-NULL: gc has not been done, NULL: gc has been done).
This fits nicely with the standard to return a pointer from all free
functions obviously.
The function to cleanup IPv6Token was defined using freep, i.e. the macro
generated a freepp function. The correct way would be to do something like
#define ipv6_token_free mfree
DEFINE_TRIVIAL_CLEANUP_FUNC(IPv6Token *, ipv6_token_free);
which would create ipv6_token_freep().
But since the cleanup function is unused, let's just drop it.
Let's make things more debuggable: when debug logging is on, let's
say which client is asking for our services.
This is helpful for easily figuring out which local process might
interfere with your debugging sessions by issuing additional requests
while you try to debug a request (I am looking at you, geoclue!).
Let's introduce a new flag that indicates whether the response was
acquired in "confidential" mode, i.e. via encrypted DNS-over-TLS, or
synthesized locally.
Fixes: #12859
Let's use the same flags type we use for client communication, i.e.
instead of "bool answer_authenticated", let's use "uint64_t
answer_query_flags", with the SD_RESOLVED_AUTHENTICATED flag.
This is mostly just search/replace, i.e. a refactoring, no change in
behaviour.
This becomes useful once in a later commit SD_RESOLVED_CONFIDENTIAL is
added to indicate resolution that either were encrypted (DNS-over-TLS)
or never left the local system.
When low-level RR resolution is requested from "resolvectl query" via
"--type=" or "--class=" no search domain logic is applied and no IDNA
translation.
Explain this in detail in the documentation, and also mentions this when
users attempt to resolve single-label names or names with international
characters in the output.
I believe the current behaviour is correct, but it is indeed surprising.
Hence the documentation and output improvement.
Fixes: #11325#10737
Memory sanitizer would report leaked memory from --boot-load-entry=help.
Maybe we should disable all bus connections from the fuzzer? It seems not
appropriate to communicate with logind. OTOH, in a real fuzzing environment
this call should just fail, so maybe that's OK.
The "socket graveyard" shall contain sockets we have sent a question out
of, but not received a reply. If we'd close thus sockets immediately
when we are not interested anymore, we'd trigger ICMP port unreachable
messages once we after all *do* get a reply. Let's avoid that, by
leaving the fds open for a bit longer, until a timeout is reached or a
reply datagram received.
Fixes: #17421
Numeric ifnames should be acceptable only if that's enabled by flag, and
refused otherwise. Hence, let's parse as ifindex first, and if that
works decide. Finally, let's refuse any numeric ifnames that are not
valid ifindexs, but look like them.
