This in unnecessarilly unpleasant: the code might report about a bus
connection, e.g. in an error message or assert. Let's let it query
the name of the object.
This partially reverts f4b2933ee7.
The code has an explicit fallback using runtime_scope_to_string(), which
is also documented in the man page. So -ENXIO should only be returned when
the fallback doesn't work, i.e. bus->runtime_scope == -EINVAL.
Fixup for f4b2933ee7.
This should fix the following errors during boot:
May 18 16:05:37 fedora systemd-update-utmp[263]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:38 fedora systemctl[360]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:38 fedora systemctl[363]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:38 fedora systemd-update-utmp[372]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:38 fedora @ystemctl[387]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:40 fedora systemd-update-utmp[477]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:41 fedora systemd-homed[509]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:41 fedora systemd-logind[510]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:41 fedora systemd-update-utmp[529]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:42 fedora systemd-user-runtime-dir[531]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:42 fedora systemctl[542]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
May 18 16:05:42 fedora systemd-hostnamed[556]: Assertion 'bus->description' failed at src/libsystemd/sd-bus/sd-bus.c:4201, function sd_bus_get_description(). Ignoring.
Now that clients might convey comm/description strings via the sockaddr,
let's actually use them on the other side, read the data via
getpeername() parse it, and include it in the "owner" creds (which is
how we call the peer's creds).
Let's pass some additional meta information along bus connections
without actually altering the communication protocol.
Pass the client comm and client description string of the bus via
including it in the abstract namespace client socket address we connect
to. This is purely informational (and entirely user controlled), but has
the benefit that servers can make use of the information if they want,
but really don't have to. It works entirely transparently.
This takes inspiration from how we convey similar information via
credential socket connections.
GCC document [1] says:
The pure attribute prohibits a function from modifying the state
of the program that is observable by means other than inspecting
the function’s return value.
And there is an example:
`int hash (char *) __attribute__ ((pure));`
... Even though hash takes a non-const pointer argument it must
not modify the array it points to, ...
But we are modifying the object pointed to by the pointer u, which is
clearly a violation of the semantic of pure.
With -ftrivial-auto-var-init (enabled by -Dmode=release), on some
targets (GCC 12.2 on AArch64 and GCC 13.1 on x86_64) performs an
optimization: as the variable "u" in bus_match_parse has been
zero-initialized (by the -ftrivial-auto-var-init option) and never
modified (because a "pure" bus_message_type_from_string is not allowed
to modify it), "u" will be always 0.
Then 0 is used to initialize .value_u8 field of struct
bus_match_component. This then causes a infinite event loop, so
"systemctl restart" never stops, and pam_systemd timeouts communicating
with logind, etc.
So we should remove the "pure" attribute here.
Fixes#26395.
[1]:https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-pure-function-attribute
If .next_entry_array_offset points to one of the previous entry or the
self entry, then the loop for entry array objects may run infinitely.
Let's assume that the offsets of each entry array object are in
increasing order, and check that in loop.
Fixes#27470.
If journal_file_data_payload() returns -EBADMSG or -EADDRNOTAVAIL,
we skip the entry and go to the next entry, but we never modify
the number of items that we pass to journal_file_append_entry_internal()
if that happens, which means we could try to append garbage to the
journal file.
Let's keep track of the number of fields we've appended to avoid this
problem.
I guess it was only a question of time until we need to add the final
frontier of notification functions: one that combines the features of
all the others:
1. specifiying a source PID
2. taking a list of fds to send along
3. accepting a format string for the status string
Hence, let's add it.
sd-event objects use hashmaps, which use module-global state, so it is not safe
to pass a sd-event object created by a module instance to another module instance
(e.g.: when two libraries static linking sd-event are pulled in a single process).
Initialize a random per-module origin id and store it in the object, and compare
it when entering a public API, and error out if they don't match, together with
the PID.
sd-journal objects use hashmaps, which use module-global state, so it is not safe
to pass a sd-journal object created by a module instance to another module instance
(e.g.: when two libraries static linking sd-journal are pulled in a single process).
Initialize a random per-module origin id and store it in the object, and compare
it when entering a public API, and error out if they don't match, together with
the PID.
sd-bus objects use hashmaps, which use module-global state, so it is not safe
to pass a sd-bus object created by a module instance to another module instance
(e.g.: when two libraries static linking sd-bus are pulled in a single process).
Initialize a random per-module origin id and store it in the object, and compare
it when entering a public API, and error out if they don't match, together with
the PID.
If we try to close after a fork, the FDs will have been cloned
too and we'll assert. This can happen for example in PAM modules.
Avoid the macro and define ref/unref by hand to do the same check.
strstrafter() is like strstr() but returns a pointer to the first
character *after* the found substring, not on the substring itself.
Quite often this is what we actually want.
Inspired by #27267 I think it makes sense to add a helper for this,
to avoid the potentially fragile manual pointer increment afterwards.
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Lennart Poettering
Xi Ruoyao
Daan De Meyer
Luca Boccassi