HRESULT forceAudioThroughHeadPhones() {
typedef int(*SET_FORCE_USE)(audio_policy_force_use_t usage, audio_policy_forced_cfg_t config);
struct sigaction sa, osa;
sa.sa_flags = SA_ONSTACK | SA_RESTART | SA_SIGINFO;
sa.sa_sigaction = [](int signo, siginfo_t* psi, void *data)->void { ucontext_t *uc = (ucontext_t *)data; };
sigaction(SIGILL, &sa, &osa);
void* hMod = dlopen("libmedia.so", RTLD_LAZY);
sigaction(SIGILL, &osa, 0);
if (0 == hMod)
return HRESULT_FROM_WIN32(ERROR_NOT_FOUND);
SET_FORCE_USE setForceUse = (SET_FORCE_USE)dlsym(hMod, "_ZN7android11AudioSystem11setForceUseE24audio_policy_force_use_t25audio_policy_forced_cfg_t");
if (0 == setForceUse)
return HRESULT_FROM_WIN32(ERROR_NOT_FOUND);
android::status_t err;
if (ERROR_SUCCESS != (err = setForceUse(AUDIO_POLICY_FORCE_FOR_MEDIA, AUDIO_POLICY_FORCE_HEADPHONES)))
return E_FAIL;
if (ERROR_SUCCESS != (err = setForceUse(AUDIO_POLICY_FORCE_FOR_SYSTEM, AUDIO_POLICY_FORCE_HEADPHONES)))
return E_FAIL;
return S_OK;
}
使用 adb shell服务调用时,我得到了相同的权限logcat错误... :
10|shell@klte:/ $ service call media.audio_policy 1 i32 2
Result: Parcel(ffffffff '....')