tree 1af03bec288eebbf811f007d2ce98e1e43793d35
parent 6db7a6d01517ef13f5a16fd0f8484a65879132c2
author Ed Tanous <edtanous@google.com> 1680564364 -0700
committer Patrick Williams <patrick@stwcx.xyz> 1680608730 +0000

Fix behavior of const_ properties

In c9eb7e3bdc5e4ff59f38c0184d17ce3a02e680d2, a regression was introduced
that would prevent the registration of properties using the
sdbusplus::vtable::property_::const_ flag, which defines a parameter as
not being modifiable.  Unfortunately, sd_bus has a check to determine
that if the non-modifiable flag was set, it would ensure that the
SD_BUS_PROPERTY method was being used without a setter.  Even if the
setter is passed in as nullptr, sd-bus still throws an error unless the
correct overload is used.

This commit makes two adjustments.  First, rather than directing
sdbsplus::asio::object_server::property_r() to a nop method, it sets the
method to nullptr.  Then at vtable registration time, that function
objects filledness is used to determine which overload of property_o
should be called.

There is one usage of const_ within the codebase, and it is within the
telemetry daemon.

Tested:  Telemetry daemon now launches its DBus objects without issue in
qemu, the environment where this issue was found.

Change-Id: I13944695ccd50371fe266048538bc5cceeaf18fd
Signed-off-by: Ed Tanous <edtanous@google.com>