func getUnitFileName() (unit string, err error) {
libname := C.CString("libsystemd.so")
defer C.free(unsafe.Pointer(libname))
handle := C.dlopen(libname, C.RTLD_LAZY)
if handle == nil {
err = fmt.Errorf("error opening libsystemd.so")
return
}
defer func() {
if r := C.dlclose(handle); r != 0 {
err = fmt.Errorf("error closing libsystemd.so")
}
}()
sym := C.CString("sd_pid_get_unit")
defer C.free(unsafe.Pointer(sym))
sd_pid_get_unit := C.dlsym(handle, sym)
if sd_pid_get_unit == nil {
err = fmt.Errorf("error resolving sd_pid_get_unit function")
return
}
var s string
u := C.CString(s)
defer C.free(unsafe.Pointer(u))
ret := C.my_sd_pid_get_unit(sd_pid_get_unit, 0, &u)
if ret < 0 {
err = fmt.Errorf("error calling sd_pid_get_unit: %v", syscall.Errno(-ret))
return
}
unit = C.GoString(u)
return
}
// CurrentUnitName attempts to retrieve the name of the systemd system unit
// from which the calling process has been invoked. It wraps the systemd
// `sd_pid_get_unit` call, with the same caveat: for processes not part of a
// systemd system unit, this function will return an error.
func CurrentUnitName() (unit string, err error) {
var h *libHandle
h, err = getHandle()
if err != nil {
return
}
defer func() {
if err1 := h.Close(); err1 != nil {
err = err1
}
}()
sym := C.CString("sd_pid_get_unit")
defer C.free(unsafe.Pointer(sym))
sd_pid_get_unit := C.dlsym(h.handle, sym)
if sd_pid_get_unit == nil {
err = fmt.Errorf("error resolving sd_pid_get_unit function")
return
}
var s string
u := C.CString(s)
defer C.free(unsafe.Pointer(u))
ret := C.my_sd_pid_get_unit(sd_pid_get_unit, 0, &u)
if ret < 0 {
err = fmt.Errorf("error calling sd_pid_get_unit: %v", syscall.Errno(-ret))
return
}
unit = C.GoString(u)
return
}
// CurrentUnitName attempts to retrieve the name of the systemd system unit
// from which the calling process has been invoked. It wraps the systemd
// `sd_pid_get_unit` call, with the same caveat: for processes not part of a
// systemd system unit, this function will return an error.
func CurrentUnitName() (unit string, err error) {
var h *dlopen.LibHandle
h, err = dlopen.GetHandle(libsystemdNames)
if err != nil {
return
}
defer func() {
if err1 := h.Close(); err1 != nil {
err = err1
}
}()
sd_pid_get_unit, err := h.GetSymbolPointer("sd_pid_get_unit")
if err != nil {
return
}
var s string
u := C.CString(s)
defer C.free(unsafe.Pointer(u))
ret := C.my_sd_pid_get_unit(sd_pid_get_unit, 0, &u)
if ret < 0 {
err = fmt.Errorf("error calling sd_pid_get_unit: %v", syscall.Errno(-ret))
return
}
unit = C.GoString(u)
return
}