Handles for services are retrieved from the service manager port, "srv:". Services are an abstraction of ports, they operate the same way except regular ports can have their handles retrieved directly from a SVC(svcConnectToPort).

Service Manager Port "srv:"

Command Header Description
0x00010002 Initialize
0x00020000 GetProcSemaphore (the handle from this gets signaled when notifications for this process gets triggered)
0x00030100 RegisterService (8-byte servicename, u32 strlen, u32 flags?)
0x000400C0 UnregisterService (8-byte servicename, u32 strlen)
0x00050100 GetServiceHandle (same input as RegisterService)
0x000600c2 Register? (8-byte servicename, u32 strlen,Handel h)
0x0007.... Unregister? (same input as UnregisterService)
0x00090040 IsRegistered This enables the specified notificationID for the current process.
0x000B0000 This returns the notificationID which was triggered, if any(see GetProcSemaphore).

Service Manager Process-Manager Port "srv:pm"

Command Header, prior to 7.0.0-13 Description
0x04030082 (u32 procid, u32 wordsz, ((wordsz<<16) | 2), serviceaccesscontrol*) Register.
0x04040040 (u32 procid) Unregister.

The Register command registers a process with the service-manager, which includes registering the serviceaccesscontrol for the process which normally originates from the exheader.

Prior to to 7.0.0-13, the commands listed for "srv:" were also accessible under this port with the same command-headers. Starting with 7.0.0-13, the commandIDs for these "srv:pm" commands were changed. "srv:pm" was originally vulnerable, this was fixed with 7.0.0-13, see here. Originally any process could use "srv:pm", however starting with 7.0.0-13 this was restricted to a maximum of 1 session. The only system title which uses "srv:pm" is the Process Manager.

Notifications

ID Description
0x100 This indicates that all processes must terminate: power-off, reboot, or FIRM-launch.
0x204 This indicates that the HOME button was pressed.