kdbus-git gained two new features:
* memfd offsets: This allows to specify a 'start' offset in kdbus_memfd
so you can send partial memfd hunks instead of always
the full memfd
* KDBUS_HELLO_UNPRIVILEGED: If passed during HELLO, the client will be
treated as unprivileged.
kdbus learned to accept both a numerical destination ID as well as a
well-known-name. In that case, kdbus makes sure that the numerical ID is in
fact the owner of the provided name and fails otherwise.
This allows for race-free assertion of a bus name owner while sending a
message, which is a requirement for bus-proxyd.
Add two new fields to sd_bus_message, and set the numerical ID to
verify_destination_id if bus_message_setup_kmsg() is called for a
message with a well-known name.
Also, set the destination's name in the kdbus item to .destination_ptr
if it is non-NULL.
Normal users should not touch these fields, and they're not publicy
accessible.
All kdbus ioctl arguments must be 8byte aligned. Make sure we use
alloca_align() and _alignas_(8) in all situations where gcc doesn't
guarantee 8-byte alignment.
Note that objects on the stack are always 8byte aligned as we put
_alignas_(8) into the structure definition in kdbus.h.
sd_bus_message_get_errno can currently return either a number of
different poitive errno values (from bus-error-mapping), or a negative
EINVAL if passed null as parameter.
The check for null parameter was introduced in 40ca29a137
at the same as the function was renamed from bus_message_to_errno and
made public API. Before becoming public the function used to return
only negative values.
It is weird to have a function return both positive and negative errno
and it generally looks like a mistake. The function is guarded by the
--enable-kdbus flags so I wonder if we still have time to fix it up?
It does not have any documentation yet. However, except for a few details
it is just a convenient way to call sd_bus_error_get_errno which is documented
to return only positive errno.
This patch makes it return only positive errno and fixes up the two
calls to the function that tried to cope with both positive and negative
values.
Mapping files as MAP_SHARED is handled by the kernel as 'writable'
mapping. Always! Even with PROT_READ. Reason for that is,
mprotect(PROT_WRITE) could change the mapping underneath and currently
there is no kernel infrastructure to add protection there. This might
change in the future, but until then, map sealed files as MAP_PRIVATE so
we don't get EPERM.
Remove the sd_ prefix from internal functions and get rid of the sd_memfd
type. As a memfd is now just a native file descriptor, we can get rid of our
own wrapper type, and also use close() and dup() on them directly.
When a caller drops all references to a bus and its messages while the
messages where still queue, this causes the bus to reference the
messages, and the messages to reference the bus, without anybody else
keeping a reference, which is something we so far considered a leak, and
tried to fix with a GC logic that would recognize cases like this, and
drop the reference.
This GC logic has been broken sofar, and remained unfixed. This commit
removes it altogther, replacing it with nothing. The rationale is that
simply because all refs to the bus have been dropped its queued messages
should *still* be written to the bus, even if the caller doesn't retain
any reference to either bus nor message. This means it was actually
wrong to attempt to clean up the bus in this case.
The proper way how applications should handle this is by explicitly
invoking sd_bus_close(), when they want busses to go away. This is
probably want they want to do anyway to avoid getting spurious
callbacks after they stopped using a bus.
It seems unnecessary to support this, and we rather should avoid
allowing this at all, so that people don't program against this
sloppily and we end up remarshalling all the time...
safe_close() automatically becomes a NOP when a negative fd is passed,
and returns -1 unconditionally. This makes it easy to write lines like
this:
fd = safe_close(fd);
Which will close an fd if it is open, and reset the fd variable
correctly.
By making use of this new scheme we can drop a > 200 lines of code that
was required to test for non-negative fds or to reset the closed fd
variable afterwards.
This broke hashtable lookups for the message cookies on s390x, which is
a 64bit BE machine where accessing 32bit values as 64bit and vice versa
will explode.
Also, while we are at it, be a bit more careful when dealing with the
64bit cookies we expose and the 32bit serial numbers dbus uses in its
payload.
Problem identified by Fridrich Strba.
Previously the returned object of constructor functions where sometimes
returned as last, sometimes as first and sometimes as second parameter.
Let's clean this up a bit. Here are the new rules:
1. The object the new object is derived from is put first, if there is any
2. The object we are creating will be returned in the next arguments
3. This is followed by any additional arguments
Rationale:
For functions that operate on an object we always put that object first.
Constructors should probably not be too different in this regard. Also,
if the additional parameters might want to use varargs which suggests to
put them last.
Note that this new scheme only applies to constructor functions, not to
all other functions. We do give a lot of freedom for those.
Note that this commit only changes the order of the new functions we
added, for old ones we accept the wrong order and leave it like that.
If -flto is used then gcc will generate a lot more warnings than before,
among them a number of use-without-initialization warnings. Most of them
without are false positives, but let's make them go away, because it
doesn't really matter.
In trying to track down a stupid linker bug, I noticed a bunch of
memset() calls that should be using memzero() to make it more "obvious"
that the options are correct (i.e. 0 is not the length, but the data to
set). So fix up all current calls to memset(foo, 0, length) to
memzero(foo, length).
This brings the calls into similar style as the respective functions in
libsystemd-journal, and also is a bi shorter and more descriptive since
it clarifies the time unit used.
