On Mon, May 9, 2022 at 7:17 AM Hamza, Muhammad <muhammad_ha...@mentor.com> wrote:
> Hello, > > > > I am trying to use swupdate services to perform updates on my BSP but > there is a problem that I am facing. > > When update usb is plugged in during the boot time, swupdate core and > swupdate-usb service run right after > > each-other where swupdate-usb service is dependent on swupdate-core > service. Therefore, the update fails as > > core has not initialized yet when swupdate-usb launches the client. > > I have tried adding service type as “exec” in swupdate core service and > have tried both Requires and After in swupdate-usb > > service but in all case swupdate-usb does not wait for core to be > initialized completely before launching. > > My understanding is that when service type is set to exec service manager > will only assume that swupdate core service is > > launched once main process of core is executed and with “Requires” set in > swupdate-usb service it should wait till > > swupdate core service has executed its main process and is assumed > launched. > Even with Type=exec, systemd won't automatically know when your process has "initialized completely". Type=exec only means that the kernel call to start executing the process has been fired off – systemd has no automatic visibility beyond that, since the initialization stage varies greatly from one program to another. (In fact, looking at your example, systemd thinks that *the shell script* is the main process, it doesn't find out about the actual daemon until later. Please get rid of the .sh script and change your ExecStart= to directly launch the daemon binary.) What you need is either Type=notify or Type=forking, and the process needs to *explicitly notify* systemd that it has reached initialization – for Type=notify it must send a READY=1 message over a socket (see sd_notify), and for Type=forking it needs to "daemonize" at the correct point. I checked the source code of swupdate on GitHub, and it seems it already has support for sending READY – there's even a whole section about systemd integration <https://github.com/sbabic/swupdate/blob/master/doc/source/swupdate.rst#systemd-integration> in its docs. So in short, you need to compile it with CONFIG_SYSTEMD, then you'll be able to use Type=notify in the .service unit. Example taken from the swupdate docs: [Service] *Type=notify* *ExecStart=/usr/bin/swupdate* -u '-t default -u http://localhost -i 25' (The "socket activation" part isn't required, but may help as well.) Finally, Type=oneshot is for services where systemd waits for the main process to start *and finish* (e.g. for services that perform a single update and don't have a daemon at all). It sounds a bit like it would be the right choice for swupdate-usb, but it's never correct to use oneshot for daemons like swupdate-core. -- Mantas Mikulėnas
