Services

Services are an abstraction of ports and are the commonly used way of inter-process communication outside of the kernel. While handles of regular ports are retrieved from SVC(svcConnectToPort), service handles are retrieved through the port srv: ("service manager").

Processes with PID less than or equal to the number of NATIVE_FIRM built-in modules (fs, sm, pm, pxi, ldr) have access to all services.

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 max_sessions)
0x000400C0	UnregisterService(8-byte servicename, u32 strlen)
0x00050100	GetServiceSessionHandle(8-byte servicename, u32 strlen, u32 flags). Flags bit0: if not set, return port-handle instead of session-handle when session-handle unavailable (max sessions/timeout?).
0x000600c2	RegisterServiceWithHandle(8-byte servicename, u32 strlen, Handle client_port)
0x0007....	UnregisterServiceWithHandle(8-byte servicename, u32 strlen)
0x0008....	GetServicePortHandle(8-byte servicename, u32 strlen, u32 flags). Bit0: return 0 instead of port handle if port was found.
0x00090040	Subscribe(u32 notification_id). This enables the specified notificationID for the current process.
0x000A0040	Unsubscribe(u32 notification_id). This disables the specified notificationID for the current process.
0x000B0000	ReceiveNotification() This returns the notificationID which was triggered, if any(see GetProcSemaphore).
0x000C0080	PublishToSubscriber(u32 notification_id, u32 flag). This fires an notification. Bit0: only fire if not already fired, bit1: return error if error happens, else it always returns 0.
0x000D....	This can fire notificationIDs and return the number of fired notificationID
0x000E....	HasAccessToService(8-byte servicename, u32 strlen). Returns 1 if your process has access to the service.

Service Manager Process-Manager Port "srv:pm"

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

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 "srv:pm" port was changed to a service. With this change, commandIDs for these 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 only the built-in NATIVE_FIRM sysmodules have access to it. 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.
0x108	error at boot?
0x204	This indicates that the HOME button was pressed.