Android 电话系统框架介绍

在android系统中rild运行在AP上，AP上的应用通过rild发送AT指令给BP，BP接收到信息后又通过rild传送给AP。AP与BP之间有两种通信方式：

1.Solicited Response:Ap向Bp发送请求，Bp给Ap发送回复,该类型的AT指令及其回调函数以数组的形式存放在Ril_commands.h文件中：

{数组中的索引号，请求回调函数，响应回调函数}

{0, NULL, NULL}, //none
{RIL_REQUEST_GET_SIM_STATUS, dispatchVoid, responseSimStatus},
{RIL_REQUEST_ENTER_SIM_PIN, dispatchStrings, responseInts},
{RIL_REQUEST_ENTER_SIM_PUK, dispatchStrings, responseInts},
{RIL_REQUEST_ENTER_SIM_PIN2, dispatchStrings, responseInts},
{RIL_REQUEST_ENTER_SIM_PUK2, dispatchStrings, responseInts},
{RIL_REQUEST_CHANGE_SIM_PIN, dispatchStrings, responseInts},
{RIL_REQUEST_CHANGE_SIM_PIN2, dispatchStrings, responseInts},
{RIL_REQUEST_ENTER_NETWORK_DEPERSONALIZATION, dispatchStrings, responseInts},
{RIL_REQUEST_GET_CURRENT_CALLS, dispatchVoid, responseCallList},
{RIL_REQUEST_DIAL, dispatchDial, responseVoid},
{RIL_REQUEST_GET_IMSI, dispatchStrings, responseString},
{RIL_REQUEST_HANGUP, dispatchInts, responseVoid},
{RIL_REQUEST_HANGUP_WAITING_OR_BACKGROUND, dispatchVoid, responseVoid},
{RIL_REQUEST_HANGUP_FOREGROUND_RESUME_BACKGROUND, dispatchVoid, responseVoid},
{RIL_REQUEST_SWITCH_WAITING_OR_HOLDING_AND_ACTIVE, dispatchVoid, responseVoid},
{RIL_REQUEST_CONFERENCE, dispatchVoid, responseVoid},
{RIL_REQUEST_UDUB, dispatchVoid, responseVoid},
{RIL_REQUEST_LAST_CALL_FAIL_CAUSE, dispatchVoid, responseInts},
{RIL_REQUEST_SIGNAL_STRENGTH, dispatchVoid, responseRilSignalStrength},
{RIL_REQUEST_VOICE_REGISTRATION_STATE, dispatchVoid, responseStrings},
{RIL_REQUEST_DATA_REGISTRATION_STATE, dispatchVoid, responseStrings},
{RIL_REQUEST_OPERATOR, dispatchVoid, responseStrings},
{RIL_REQUEST_RADIO_POWER, dispatchInts, responseVoid},
{RIL_REQUEST_DTMF, dispatchString, responseVoid},
{RIL_REQUEST_SEND_SMS, dispatchStrings, responseSMS},
{RIL_REQUEST_SEND_SMS_EXPECT_MORE, dispatchStrings, responseSMS},
{RIL_REQUEST_SETUP_DATA_CALL, dispatchDataCall, responseSetupDataCall},
{RIL_REQUEST_SIM_IO, dispatchSIM_IO, responseSIM_IO},
{RIL_REQUEST_SEND_USSD, dispatchString, responseVoid},
{RIL_REQUEST_CANCEL_USSD, dispatchVoid, responseVoid},
{RIL_REQUEST_GET_CLIR, dispatchVoid, responseInts},
{RIL_REQUEST_SET_CLIR, dispatchInts, responseVoid},
{RIL_REQUEST_QUERY_CALL_FORWARD_STATUS, dispatchCallForward, responseCallForwards},
{RIL_REQUEST_SET_CALL_FORWARD, dispatchCallForward, responseVoid},
{RIL_REQUEST_QUERY_CALL_WAITING, dispatchInts, responseInts},
{RIL_REQUEST_SET_CALL_WAITING, dispatchInts, responseVoid},
{RIL_REQUEST_SMS_ACKNOWLEDGE, dispatchInts, responseVoid},
{RIL_REQUEST_GET_IMEI, dispatchVoid, responseString},
{RIL_REQUEST_GET_IMEISV, dispatchVoid, responseString},
{RIL_REQUEST_ANSWER,dispatchVoid, responseVoid},
{RIL_REQUEST_DEACTIVATE_DATA_CALL, dispatchStrings, responseVoid},
{RIL_REQUEST_QUERY_FACILITY_LOCK, dispatchStrings, responseInts},
{RIL_REQUEST_SET_FACILITY_LOCK, dispatchStrings, responseInts},
{RIL_REQUEST_CHANGE_BARRING_PASSWORD, dispatchStrings, responseVoid},
{RIL_REQUEST_QUERY_NETWORK_SELECTION_MODE, dispatchVoid, responseInts},
{RIL_REQUEST_SET_NETWORK_SELECTION_AUTOMATIC, dispatchVoid, responseVoid},
{RIL_REQUEST_SET_NETWORK_SELECTION_MANUAL, dispatchString, responseVoid},
{RIL_REQUEST_QUERY_AVAILABLE_NETWORKS , dispatchVoid, responseStrings},
{RIL_REQUEST_DTMF_START, dispatchString, responseVoid},
{RIL_REQUEST_DTMF_STOP, dispatchVoid, responseVoid},
{RIL_REQUEST_BASEBAND_VERSION, dispatchVoid, responseString},
{RIL_REQUEST_SEPARATE_CONNECTION, dispatchInts, responseVoid},
{RIL_REQUEST_SET_MUTE, dispatchInts, responseVoid},
{RIL_REQUEST_GET_MUTE, dispatchVoid, responseInts},
{RIL_REQUEST_QUERY_CLIP, dispatchVoid, responseInts},
{RIL_REQUEST_LAST_DATA_CALL_FAIL_CAUSE, dispatchVoid, responseInts},
{RIL_REQUEST_DATA_CALL_LIST, dispatchVoid, responseDataCallList},
{RIL_REQUEST_RESET_RADIO, dispatchVoid, responseVoid},
{RIL_REQUEST_OEM_HOOK_RAW, dispatchRaw, responseRaw},
{RIL_REQUEST_OEM_HOOK_STRINGS, dispatchStrings, responseStrings},
{RIL_REQUEST_SCREEN_STATE, dispatchInts, responseVoid},
{RIL_REQUEST_SET_SUPP_SVC_NOTIFICATION, dispatchInts, responseVoid},
{RIL_REQUEST_WRITE_SMS_TO_SIM, dispatchSmsWrite, responseInts},
{RIL_REQUEST_DELETE_SMS_ON_SIM, dispatchInts, responseVoid},
{RIL_REQUEST_SET_BAND_MODE, dispatchInts, responseVoid},
{RIL_REQUEST_QUERY_AVAILABLE_BAND_MODE, dispatchVoid, responseInts},
{RIL_REQUEST_STK_GET_PROFILE, dispatchVoid, responseString},
{RIL_REQUEST_STK_SET_PROFILE, dispatchString, responseVoid},
{RIL_REQUEST_STK_SEND_ENVELOPE_COMMAND, dispatchString, responseString},
{RIL_REQUEST_STK_SEND_TERMINAL_RESPONSE, dispatchString, responseVoid},
{RIL_REQUEST_STK_HANDLE_CALL_SETUP_REQUESTED_FROM_SIM, dispatchInts, responseVoid},
{RIL_REQUEST_EXPLICIT_CALL_TRANSFER, dispatchVoid, responseVoid},
{RIL_REQUEST_SET_PREFERRED_NETWORK_TYPE, dispatchInts, responseVoid},
{RIL_REQUEST_GET_PREFERRED_NETWORK_TYPE, dispatchVoid, responseInts},
{RIL_REQUEST_GET_NEIGHBORING_CELL_IDS, dispatchVoid, responseCellList},
{RIL_REQUEST_SET_LOCATION_UPDATES, dispatchInts, responseVoid},
{RIL_REQUEST_CDMA_SET_SUBSCRIPTION_SOURCE, dispatchInts, responseVoid},
{RIL_REQUEST_CDMA_SET_ROAMING_PREFERENCE, dispatchInts, responseVoid},
{RIL_REQUEST_CDMA_QUERY_ROAMING_PREFERENCE, dispatchVoid, responseInts},
{RIL_REQUEST_SET_TTY_MODE, dispatchInts, responseVoid},
{RIL_REQUEST_QUERY_TTY_MODE, dispatchVoid, responseInts},
{RIL_REQUEST_CDMA_SET_PREFERRED_VOICE_PRIVACY_MODE, dispatchInts, responseVoid},
{RIL_REQUEST_CDMA_QUERY_PREFERRED_VOICE_PRIVACY_MODE, dispatchVoid, responseInts},
{RIL_REQUEST_CDMA_FLASH, dispatchString, responseVoid},
{RIL_REQUEST_CDMA_BURST_DTMF, dispatchStrings, responseVoid},
{RIL_REQUEST_CDMA_VALIDATE_AND_WRITE_AKEY, dispatchString, responseVoid},
{RIL_REQUEST_CDMA_SEND_SMS, dispatchCdmaSms, responseSMS},
{RIL_REQUEST_CDMA_SMS_ACKNOWLEDGE, dispatchCdmaSmsAck, responseVoid},
{RIL_REQUEST_GSM_GET_BROADCAST_SMS_CONFIG, dispatchVoid, responseGsmBrSmsCnf},
{RIL_REQUEST_GSM_SET_BROADCAST_SMS_CONFIG, dispatchGsmBrSmsCnf, responseVoid},
{RIL_REQUEST_GSM_SMS_BROADCAST_ACTIVATION, dispatchInts, responseVoid},
{RIL_REQUEST_CDMA_GET_BROADCAST_SMS_CONFIG, dispatchVoid, responseCdmaBrSmsCnf},
{RIL_REQUEST_CDMA_SET_BROADCAST_SMS_CONFIG, dispatchCdmaBrSmsCnf, responseVoid},
{RIL_REQUEST_CDMA_SMS_BROADCAST_ACTIVATION, dispatchInts, responseVoid},
{RIL_REQUEST_CDMA_SUBSCRIPTION, dispatchVoid, responseStrings},
{RIL_REQUEST_CDMA_WRITE_SMS_TO_RUIM, dispatchRilCdmaSmsWriteArgs, responseInts},
{RIL_REQUEST_CDMA_DELETE_SMS_ON_RUIM, dispatchInts, responseVoid},
{RIL_REQUEST_DEVICE_IDENTITY, dispatchVoid, responseStrings},
{RIL_REQUEST_EXIT_EMERGENCY_CALLBACK_MODE, dispatchVoid, responseVoid},
{RIL_REQUEST_GET_SMSC_ADDRESS, dispatchVoid, responseString},
{RIL_REQUEST_SET_SMSC_ADDRESS, dispatchString, responseVoid},
{RIL_REQUEST_REPORT_SMS_MEMORY_STATUS, dispatchInts, responseVoid},
{RIL_REQUEST_REPORT_STK_SERVICE_IS_RUNNING, dispatchVoid, responseVoid},
{RIL_REQUEST_CDMA_GET_SUBSCRIPTION_SOURCE, dispatchCdmaSubscriptionSource, responseInts},
{RIL_REQUEST_ISIM_AUTHENTICATION, dispatchString, responseString},
{RIL_REQUEST_ACKNOWLEDGE_INCOMING_GSM_SMS_WITH_PDU, dispatchStrings, responseVoid},
{RIL_REQUEST_STK_SEND_ENVELOPE_WITH_STATUS, dispatchString, responseSIM_IO},
{RIL_REQUEST_VOICE_RADIO_TECH, dispatchVoiceRadioTech, responseInts},

2.unSolicited Response:Bp主动给Ap发送事件,该类型的AT指令及其回调函数以数组的形式存放在ril_unsol_commands.h文件中：

{数组中的索引号，响应回调函数，类型}

{RIL_UNSOL_RESPONSE_RADIO_STATE_CHANGED, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_VOICE_NETWORK_STATE_CHANGED, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_NEW_SMS, responseString, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_NEW_SMS_STATUS_REPORT, responseString, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_NEW_SMS_ON_SIM, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_ON_USSD, responseStrings, WAKE_PARTIAL},
{RIL_UNSOL_ON_USSD_REQUEST, responseVoid, DONT_WAKE},
{RIL_UNSOL_NITZ_TIME_RECEIVED, responseString, WAKE_PARTIAL},
{RIL_UNSOL_SIGNAL_STRENGTH, responseRilSignalStrength, DONT_WAKE},
{RIL_UNSOL_DATA_CALL_LIST_CHANGED, responseDataCallList, WAKE_PARTIAL},
{RIL_UNSOL_SUPP_SVC_NOTIFICATION, responseSsn, WAKE_PARTIAL},
{RIL_UNSOL_STK_SESSION_END, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_STK_PROACTIVE_COMMAND, responseString, WAKE_PARTIAL},
{RIL_UNSOL_STK_EVENT_NOTIFY, responseString, WAKE_PARTIAL},
{RIL_UNSOL_STK_CALL_SETUP, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_SIM_SMS_STORAGE_FULL, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_SIM_REFRESH, responseSimRefresh, WAKE_PARTIAL},
{RIL_UNSOL_CALL_RING, responseCallRing, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_SIM_STATUS_CHANGED, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_CDMA_NEW_SMS, responseCdmaSms, WAKE_PARTIAL},
{RIL_UNSOL_RESPONSE_NEW_BROADCAST_SMS, responseRaw, WAKE_PARTIAL},
{RIL_UNSOL_CDMA_RUIM_SMS_STORAGE_FULL, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_RESTRICTED_STATE_CHANGED, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_ENTER_EMERGENCY_CALLBACK_MODE, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_CDMA_CALL_WAITING, responseCdmaCallWaiting, WAKE_PARTIAL},
{RIL_UNSOL_CDMA_OTA_PROVISION_STATUS, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_CDMA_INFO_REC, responseCdmaInformationRecords, WAKE_PARTIAL},
{RIL_UNSOL_OEM_HOOK_RAW, responseRaw, WAKE_PARTIAL},
{RIL_UNSOL_RINGBACK_TONE, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_RESEND_INCALL_MUTE, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_CDMA_SUBSCRIPTION_SOURCE_CHANGED, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_CDMA_PRL_CHANGED, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_EXIT_EMERGENCY_CALLBACK_MODE, responseVoid, WAKE_PARTIAL},
{RIL_UNSOL_RIL_CONNECTED, responseInts, WAKE_PARTIAL},
{RIL_UNSOL_VOICE_RADIO_TECH_CHANGED, responseInts, WAKE_PARTIAL},

不同手机厂商使用的AT命令不完全相同，为了保密，AP与BP之间通过各厂商自己的相关动态库来通信。

RIL模块由rild守护进程、libril.so、librefrence.so三部分组成：

1.rild模块被编译为一个可执行文件，实现一个main函数作为整个ril模块的入口点。在初始化时使用dlopen打开librefrence_ril.so，从中取出并执行RIL_Init函数，得到RIL_RadioFunctions指针，通过RIL_register()函数注册到libril.so库中，其源码结构如下：

2.libril.so是共享库，主要负责同上层的通信工作，接收ril的请求，并传递给librefrence_ril.so，同时将librefrence_ril.so返回的消息送给调用进程，源码结构如下所示：

3.librefrence_ril.so是由各手机厂商自己实现，在rild进程运行中通过dlopen方式加载，主要负责跟modem硬件通信，转换来自libril.so的请求为AT命令，同时监听Modem的反馈信息给libril.so

Android的电话系统主要分为三个部分，java层的各种电话相关应用，java层的Phone Service，主要为上层提供API，同时与native进行通信，可以看做为电话系统的客户端，native层的电话服务进程RILD，负责为上层提供各种电话功能服务，直接与modem进行交互：

Android电话系统设计框架图：

由于Android 开发者使用的Modem 是不一样的，各种指令格式，初始化序列都可能不一样，所以为了消除这些差别，Android 设计者将ril 做了一个抽象，使用一个虚拟电话的概念，不同modem相关的AT指令或者通信协议编译成相应的动态链接库.so文件，Rild 是具体的AT 指令合成者和应答解析者。

Android电话系统代码结构图：

RILD框架设计

在android的电话系统中，在native层实现了电话服务的服务端，由RILD服务与modem的交互，在java层实现电话的客户端，本文主要介绍电话系统的服务端RILD进程，以下是RILD的设计框架图：

RILD源码分析

接下来通过源码对RILD的整个框架进行详细介绍。

在kernel启动完成后，将启动第一个应用进程Init进程，在android之Init进程启动过程源码分析一文中对init进程的启动流程进行了详细的介绍。init进程在启动过程中将读取init.rc文件来启动一些重量级的native服务，rild进程就是通过配置在init.rc中来启动的。

service ril-daemon /system/bin/rild
class main
socket rild stream 660 root radio
socket rild-debug stream 660 radio system
user root
group radio cache inet misc audio sdcard_rw log

RILD进程入口函数分析

接下来给出的是RILD进程启动的时序图：

hardware\ril\rild\rild.c

int main(int argc, char **argv)
{
const char * rilLibPath = NULL;
char **rilArgv;
void *dlHandle;
const RIL_RadioFunctions *(*rilInit)(const struct RIL_Env *, int, char **);
const RIL_RadioFunctions *funcs;
char libPath[PROPERTY_VALUE_MAX];
unsigned char hasLibArgs = 0;
int i;
　　umask(S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH);
　　//rild启动无参数
for (i = 1; i < argc ;) {
if (0 == strcmp(argv[i], "-l") && (argc - i > 1)) {
rilLibPath = argv[i + 1];
i += 2;
} else if (0 == strcmp(argv[i], "--")) {
i++;
hasLibArgs = 1;
break;
} else {
usage(argv[0]);
}
}
　　if (rilLibPath == NULL) {
　　 //通过Android属性系统读取属性"rild.libpath"的值，即lib库的存放路径
if ( 0 == property_get(LIB_PATH_PROPERTY, libPath, NULL)) {
goto done;
} else {
rilLibPath = libPath;
}
　　}
##################################################################################
判断是否为模拟器
##################################################################################
#if 1
{
static char* arg_overrides[3];
static char arg_device[32];
int done = 0;
#define REFERENCE_RIL_PATH "/system/lib/libreference-ril.so"
/* first, read /proc/cmdline into memory */
char buffer[1024], *p, *q;
int len;
int fd = open("/proc/cmdline",O_RDONLY);
if (fd < 0) {
LOGD("could not open /proc/cmdline:%s", strerror(errno));
goto OpenLib;
}
//读取/proc/cmdline文件中的内容
do {
len = read(fd,buffer,sizeof(buffer)); }
while (len == -1 && errno == EINTR);
if (len < 0) {
LOGD("could not read /proc/cmdline:%s", strerror(errno));
close(fd);
goto OpenLib;
}
close(fd);
//判断是否为模拟器，对于真机，此处条件为false
if (strstr(buffer,  "android.qemud=") != NULL)
{
int tries = 5;
#define QEMUD_SOCKET_NAME "qemud"
while (1) {
int fd;
sleep(1);
fd = socket_local_client(QEMUD_SOCKET_NAME,
ANDROID_SOCKET_NAMESPACE_RESERVED,
SOCK_STREAM );
if (fd >= 0) {
close(fd);
snprintf( arg_device, sizeof(arg_device), "%s/%s",
ANDROID_SOCKET_DIR, QEMUD_SOCKET_NAME );
arg_overrides[1] = "-s";
arg_overrides[2] = arg_device;
done = 1;
break;
}
LOGD("could not connect to %s socket: %s",QEMUD_SOCKET_NAME, strerror(errno));
if (--tries == 0)
break;
}
if (!done) {
LOGE("could not connect to %s socket (giving up): %s",
QEMUD_SOCKET_NAME, strerror(errno));
while(1)
sleep(0x00ffffff);
}
}

/* otherwise, try to see if we passed a device name from the kernel */
if (!done) do { //true
#define KERNEL_OPTION "android.ril="
#define DEV_PREFIX "/dev/"
//判断/proc/cmdline中的内容是否包含"android.ril="
p = strstr( buffer, KERNEL_OPTION );
if (p == NULL)
break;
p += sizeof(KERNEL_OPTION)-1;
q = strpbrk( p, " \t\n\r" );
if (q != NULL)
*q = 0;
snprintf( arg_device, sizeof(arg_device), DEV_PREFIX "%s", p );
arg_device[sizeof(arg_device)-1] = 0;
arg_overrides[1] = "-d";
arg_overrides[2] = arg_device;
done = 1;
} while (0);

if (done) { //false
argv = arg_overrides;
argc = 3;
i = 1;
hasLibArgs = 1;
rilLibPath = REFERENCE_RIL_PATH;
LOGD("overriding with %s %s", arg_overrides[1], arg_overrides[2]);
}
}
OpenLib:
#endif
##################################################################################
动态库装载
##################################################################################

　　switchUser();//设置Rild进程的组用户为radio
　　//加载厂商自定义的库
①dlHandle = dlopen(rilLibPath, RTLD_NOW);
if (dlHandle == NULL) {
fprintf(stderr, "dlopen failed: %s\n", dlerror());
exit(-1);
　　}
　　//创建客户端事件监听线程
　　②RIL_startEventLoop();
　　//通过dlsym定位到RIL_Init函数的地址，并且强制转换为RIL_RadioFunctions的函数指针
③rilInit = (const RIL_RadioFunctions *(*)(const struct RIL_Env *, int, char **))dlsym(dlHandle, "RIL_Init");
if (rilInit == NULL) {
fprintf(stderr, "RIL_Init not defined or exported in %s\n", rilLibPath);
exit(-1);
}
if (hasLibArgs) {  //false
rilArgv = argv + i - 1;
argc = argc -i + 1;
} else {
static char * newArgv[MAX_LIB_ARGS];
static char args[PROPERTY_VALUE_MAX];
rilArgv = newArgv;
property_get(LIB_ARGS_PROPERTY, args, "");//通过属性系统读取"rild.libargs"属性值
argc = make_argv(args, rilArgv);
}
// Make sure there's a reasonable argv[0]
　　rilArgv[0] = argv[0];
　　//调用RIL_Init函数来初始化rild，传入参数s_rilEnv，返回RIL_RadioFunctions地址
　　④funcs = rilInit(&s_rilEnv, argc, rilArgv);
　　//注册客户端事件处理接口RIL_RadioFunctions，并创建socket监听事件
⑤RIL_register(funcs);
done:
while(1) {
// sleep(UINT32_MAX) seems to return immediately on bionic
sleep(0x00ffffff);
}
}

在main函数中主要完成以下工作:

1.解析命令行参数，通过判断是否为模拟器采取不同的方式来读取libreference-ril.so库的存放路径；

2.使用dlopen手动装载libreference-ril.so库；

3.启动事件循环处理；

4.从libreference-ril.so库中取得RIL_Init函数地址，并使用该函数将libril.so库中的RIL_Env接口注册到libreference-ril.so库，同时将libreference-ril.so库中的RIL_RadioFunctions接口注册到到libril.so库中，建立起libril.so库与libreference-ril.so库通信桥梁；

启动事件循环处理eventLoop工作线程

建立多路I/O驱动机制的消息队列，用来接收上层发出的命令以及往Modem发送AT指令的工作，时整个RIL系统的核心部分。创建一个事件分发线程s_tid_dispatch，线程执行体为eventLoop。

hardware\ril\libril\Ril.cpp

extern "C" void RIL_startEventLoop(void) {
int ret;
pthread_attr_t attr;
/* spin up eventLoop thread and wait for it to get started */
s_started = 0;
pthread_mutex_lock(&s_startupMutex);
pthread_attr_init (&attr);
　　pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
　　//创建一个工作线程eventLoop
　　ret = pthread_create(&s_tid_dispatch, &attr, eventLoop, NULL);
　　//确保函数返回前eventLoop线程启动运行
while (s_started == 0) {
pthread_cond_wait(&s_startupCond, &s_startupMutex);
}
pthread_mutex_unlock(&s_startupMutex);
if (ret < 0) {
LOGE("Failed to create dispatch thread errno:%d", errno);
return;
}
}

eventLoop执行时序图：

static void * eventLoop(void *param) {
int ret;
int filedes[2];
ril_event_init(); //初始化请求队列
pthread_mutex_lock(&s_startupMutex);
s_started = 1; //eventLoop线程运行标志位
pthread_cond_broadcast(&s_startupCond);
　　pthread_mutex_unlock(&s_startupMutex);
　　//创建匿名管道
ret = pipe(filedes);
if (ret < 0) {
LOGE("Error in pipe() errno:%d", errno);
return NULL;
　　}
　　//s_fdWakeupRead为管道读端
　　s_fdWakeupRead = filedes[0];
　　//s_fdWakeupWrite为管道写端
　　s_fdWakeupWrite = filedes[1];
　　//设置管道读端为O_NONBLOCK非阻塞
　　fcntl(s_fdWakeupRead, F_SETFL, O_NONBLOCK);
　　//初始化s_wakeupfd_event结构体的内容，句柄为s_fdWakeupRead，回调函数为 processWakeupCallback
ril_event_set (&s_wakeupfd_event, s_fdWakeupRead,  true,processWakeupCallback, NULL);
①rilEventAddWakeup (&s_wakeupfd_event);
// Only returns on error
②ril_event_loop();
LOGE ("error in event_loop_base errno:%d", errno);
return NULL;
}

在rild中定义了event的概念，Rild 支持两种类型的事件：

1. 定时事件：根据事件的执行时间来启动执行，通过ril_timer_add添加到time_list队列中

2. Wakeup事件：这些事件的句柄fd将加入的select IO多路复用的句柄池readFDs中，当对应的fd可读时将触发这些事件。对于处于listen端的socket，fd可读表示有个客户端连接，此时需要调用accept接受连接。

事件定义如下：

struct ril_event {
struct ril_event *next;
struct ril_event *prev;
int fd; //文件句柄
int index; //该事件在监控表中的索引
bool persist; //如果是保持的，则不从watch_list 中删除
struct timeval timeout;  //任务执行时间
ril_event_cb func; //回调事件处理函数
void *param; //回调时参数
};

在Rild进程中的几个重要事件有

static struct ril_event s_commands_event;
ril_event_set (&s_commands_event, s_fdCommand, 1,processCommandsCallback, p_rs)

static struct ril_event s_wakeupfd_event;
ril_event_set (&s_wakeupfd_event, s_fdWakeupRead,  true,processWakeupCallback, NULL)

static struct ril_event s_listen_event;
ril_event_set (&s_listen_event, s_fdListen, false,listenCallback, NULL)

static struct ril_event s_wake_timeout_event;
ril_timer_add(&(p_info->event), &myRelativeTime)；

static struct ril_event s_debug_event;
ril_event_set (&s_debug_event, s_fdDebug, true,debugCallback, NULL)

在RILD中定义了三个事件队列，用于处理不同的事件：

/事件监控队列

static struct ril_event * watch_table[MAX_FD_EVENTS];

//定时事件队列

static struct ril_event timer_list;

//处理事件队列

static struct ril_event pending_list; //待处理事件队列，事件已经触发，需要所回调处理的事件

添加事件

1.添加 Wakeup 事件

static void rilEventAddWakeup(struct ril_event *ev) {
ril_event_add(ev); //向监控表watch_table添加一个s_wakeupfd_event事件
triggerEvLoop(); //向管道s_fdWakeupWrite中写入之来触发事件循环
}

void ril_event_add(struct ril_event * ev)
{
dlog("~~~~ +ril_event_add ~~~~");
MUTEX_ACQUIRE();
for (int i = 0; i < MAX_FD_EVENTS; i++) { //遍历监控表watch_table
if (watch_table[i] == NULL) {  //从监控表中查找空闲的索引，然后把该任务加入到监控表中
watch_table[i] = ev; //向监控表中添加事件
ev->index = i; //事件的索引设置为在监控表中的索引
dlog("~~~~ added at %d ~~~~", i);
dump_event(ev);
FD_SET(ev->fd, &readFds); //将添加的事件对应的句柄添加到句柄池readFds中
if (ev->fd >= nfds) nfds = ev->fd+1; //修改句柄最大值
dlog("~~~~ nfds = %d ~~~~", nfds);
break;
}
}
MUTEX_RELEASE();
dlog("~~~~ -ril_event_add ~~~~");
}

2.添加定时事件

void ril_timer_add(struct ril_event * ev, struct timeval * tv)
{
dlog("~~~~ +ril_timer_add ~~~~");
MUTEX_ACQUIRE();
struct ril_event * list;
if (tv != NULL) {
list = timer_list.next;
ev->fd = -1; // make sure fd is invalid
struct timeval now;
getNow(&now);
timeradd(&now, tv, &ev->timeout);
// keep list sorted
while (timercmp(&list->timeout, &ev->timeout, < ) && (list != &timer_list)) {
list = list->next;
}
// list now points to the first event older than ev
addToList(ev, list);
}
MUTEX_RELEASE();
dlog("~~~~ -ril_timer_add ~~~~");
}

触发事件

static void triggerEvLoop() {
int ret;
　　if (!pthread_equal(pthread_self(), s_tid_dispatch)) { //如果当前线程ID不等于事件分发线程eventLoop的线程ID
do {
ret = write (s_fdWakeupWrite, " ", 1); //向管道写端写入值1来触发eventLoop事件循环
} while (ret < 0 && errno == EINTR);
}
}

处理事件

void ril_event_loop()
{
int n;
fd_set rfds;
struct timeval tv;
struct timeval * ptv;
for (;;) {
memcpy(&rfds, &readFds, sizeof(fd_set));
if (-1 == calcNextTimeout(&tv)) {
dlog("~~~~ no timers; blocking indefinitely ~~~~");
ptv = NULL;
} else {
dlog("~~~~ blocking for %ds + %dus ~~~~", (int)tv.tv_sec, (int)tv.tv_usec);
ptv = &tv;
}
//使用select 函数等待在FDS 上,只要FDS 中记录的设备有数据到来，select 就会设置相应的标志位并返回。readFDS 记录了所有的事件相关设备句柄。readFDS 中句柄是在在AddEvent 加入的。
printReadies(&rfds);
n = select(nfds, &rfds, NULL, NULL, ptv);
printReadies(&rfds);
dlog("~~~~ %d events fired ~~~~", n);
if (n < 0) {
if (errno == EINTR) continue;
LOGE("ril_event: select error (%d)", errno);
return;
}
processTimeouts(); //从timer_list中查询执行时间已到的事件，并添加到pending_list中
processReadReadies(&rfds, n); //从watch_table中查询数据可读的事件，并添加到pending_list中去处理，如果该事件不是持久事件，则同时从watch_table中删除
//遍历pending_list，调用事件处理回调函数处理所有事件
firePending();
}
}

在eventLoop工作线程中，循环处理到来的事件及定时结束事件，整个处理流程如下图所示：

首先通过Linux中的select多路I/O复用对句柄池中的所有句柄进行监控，当有事件到来时select返回，否则阻塞。当select返回时，表示有事件的到来，通过调用processTimeouts函数来处理超时事件，处理方式是遍历time_list链表以查询超时事件，并将超时事件移入到pending_list链表中，接着调用processReadReadies函数来处理触发的事件，处理方式为遍历watch_table列表以查询触发的事件，并将触发的事件移入到pending_list链表中，如果该事件不是持久事件，还需要从watch_table列表中移除，当查询完两种待处理的事件并放入到pending_list链表中后，调用firePending函数对待处理的事件进行集中处理，处理方式为遍历链表，调用每一个事件的回调函数。

1.超时事件查询

static void processTimeouts()
{
dlog("~~~~ +processTimeouts ~~~~");
MUTEX_ACQUIRE();
struct timeval now;
struct ril_event * tev = timer_list.next;
struct ril_event * next;
getNow(&now); //获取当前时间
　　dlog("~~~~ Looking for timers <= %ds + %dus ~~~~", (int)now.tv_sec, (int)now.tv_usec);
　　//如果当前时间大于事件的超时时间，则将该事件从timer_list中移除，添加到pending_list
while ((tev != &timer_list) && (timercmp(&now, &tev->timeout, >))) {
dlog("~~~~ firing timer ~~~~");
next = tev->next;
removeFromList(tev); //从timer_list中移除事件
addToList(tev, &pending_list); //将事件添加到pending_list
tev = next;
}
MUTEX_RELEASE();
dlog("~~~~ -processTimeouts ~~~~");
}

2.可读事件查询

static void processReadReadies(fd_set * rfds, int n)
{
dlog("~~~~ +processReadReadies (%d) ~~~~", n);
　　MUTEX_ACQUIRE();
　　//遍历watch_table数组，根据select返回的句柄n查找对应的事件
for (int i = 0; (i < MAX_FD_EVENTS) && (n > 0); i++) {
struct ril_event * rev = watch_table[i]; //得到相应的事件
if (rev != NULL && FD_ISSET(rev->fd, rfds)) {
addToList(rev, &pending_list); //将该事件添加到pending_list中
if (rev->persist == false) { //如果该事件不是持久事件还要从watch_table中移除
removeWatch(rev, i);
}
n--;
}
}
MUTEX_RELEASE();
dlog("~~~~ -processReadReadies (%d) ~~~~", n);
}

3.事件处理

static void firePending()
{
dlog("~~~~ +firePending ~~~~");
struct ril_event * ev = pending_list.next;
while (ev != &pending_list) { //遍历pending_list链表，处理链表中的所有事件
struct ril_event * next = ev->next;
removeFromList(ev); //将处理完的事件从pending_list中移除
ev->func(ev->fd, 0, ev->param); //调用事件处理的回调函数
ev = next;
}
dlog("~~~~ -firePending ~~~~");
}

RIL_Env定义

hardware\ril\include\telephony\ril.h

struct RIL_Env {
//动态库完成请求后通知处理结果的接口
　　void (*OnRequestComplete)(RIL_Token t, RIL_Errno e,void *response, size_t responselen);
//动态库unSolicited Response通知接口
　　void (*OnUnsolicitedResponse)(int unsolResponse, const void *data,size_t datalen);
//向Rild提交一个超时任务的接口
void (*RequestTimedCallback) (RIL_TimedCallback callback,void *param, const struct timeval *relativeTime);
};

hardware\ril\rild\rild.c

s_rilEnv变量定义：

static struct RIL_Env s_rilEnv = {
RIL_onRequestComplete,
RIL_onUnsolicitedResponse,
RIL_requestTimedCallback
};

在hardware\ril\libril\ril.cpp中实现了RIL_Env的各个接口函数

1.RIL_onRequestComplete

extern "C" void RIL_onRequestComplete(RIL_Token t, RIL_Errno e, void *response, size_t responselen) {
RequestInfo *pRI;
int ret;
size_t errorOffset;
pRI = (RequestInfo *)t;
if (!checkAndDequeueRequestInfo(pRI)) {
LOGE ("RIL_onRequestComplete: invalid RIL_Token");
return;
}
if (pRI->local > 0) {
// Locally issued command...void only!
// response does not go back up the command socket
LOGD("C[locl]< %s", requestToString(pRI->pCI->requestNumber));
goto done;
}
appendPrintBuf("[%04d]< %s",pRI->token, requestToString(pRI->pCI->requestNumber));
if (pRI->cancelled == 0) {
Parcel p;
p.writeInt32 (RESPONSE_SOLICITED);
p.writeInt32 (pRI->token);
errorOffset = p.dataPosition();
p.writeInt32 (e);
if (response != NULL) {
// there is a response payload, no matter success or not.
ret = pRI->pCI->responseFunction(p, response, responselen);
/* if an error occurred, rewind and mark it */
if (ret != 0) {
p.setDataPosition(errorOffset);
p.writeInt32 (ret);
}
}
if (e != RIL_E_SUCCESS) {
appendPrintBuf("%s fails by %s", printBuf, failCauseToString(e));
}
if (s_fdCommand < 0) {
LOGD ("RIL onRequestComplete: Command channel closed");
}
sendResponse(p);
}
done:
free(pRI);
}

通过调用responseXXX将底层响应传给客户进程

2.RIL_onUnsolicitedResponse

extern "C" void RIL_onUnsolicitedResponse(int unsolResponse, void *data,
size_t datalen)
{
int unsolResponseIndex;
int ret;
int64_t timeReceived = 0;
bool shouldScheduleTimeout = false;
if (s_registerCalled == 0) {
// Ignore RIL_onUnsolicitedResponse before RIL_register
LOGW("RIL_onUnsolicitedResponse called before RIL_register");
return;
}
unsolResponseIndex = unsolResponse - RIL_UNSOL_RESPONSE_BASE;
if ((unsolResponseIndex < 0)
|| (unsolResponseIndex >= (int32_t)NUM_ELEMS(s_unsolResponses))) {
LOGE("unsupported unsolicited response code %d", unsolResponse);
return;
}
// Grab a wake lock if needed for this reponse,
// as we exit we'll either release it immediately
// or set a timer to release it later.
switch (s_unsolResponses[unsolResponseIndex].wakeType) {
case WAKE_PARTIAL:
grabPartialWakeLock();
shouldScheduleTimeout = true;
break;
case DONT_WAKE:
default:
// No wake lock is grabed so don't set timeout
shouldScheduleTimeout = false;
break;
}
// Mark the time this was received, doing this
// after grabing the wakelock incase getting
// the elapsedRealTime might cause us to goto
// sleep.
if (unsolResponse == RIL_UNSOL_NITZ_TIME_RECEIVED) {
timeReceived = elapsedRealtime();
}
appendPrintBuf("[UNSL]< %s", requestToString(unsolResponse));
Parcel p;
p.writeInt32 (RESPONSE_UNSOLICITED);
p.writeInt32 (unsolResponse);
ret = s_unsolResponses[unsolResponseIndex].responseFunction(p, data, datalen);
if (ret != 0) {
// Problem with the response. Don't continue;
goto error_exit;
}
// some things get more payload
switch(unsolResponse) {
case RIL_UNSOL_RESPONSE_RADIO_STATE_CHANGED:
p.writeInt32(s_callbacks.onStateRequest());
appendPrintBuf("%s {%s}", printBuf,
radioStateToString(s_callbacks.onStateRequest()));
break;
case RIL_UNSOL_NITZ_TIME_RECEIVED:
// Store the time that this was received so the
// handler of this message can account for
// the time it takes to arrive and process. In
// particular the system has been known to sleep
// before this message can be processed.
p.writeInt64(timeReceived);
break;
}
ret = sendResponse(p);
if (ret != 0 && unsolResponse == RIL_UNSOL_NITZ_TIME_RECEIVED) {
// Unfortunately, NITZ time is not poll/update like everything
// else in the system. So, if the upstream client isn't connected,
// keep a copy of the last NITZ response (with receive time noted
// above) around so we can deliver it when it is connected
if (s_lastNITZTimeData != NULL) {
free (s_lastNITZTimeData);
s_lastNITZTimeData = NULL;
}
s_lastNITZTimeData = malloc(p.dataSize());
s_lastNITZTimeDataSize = p.dataSize();
memcpy(s_lastNITZTimeData, p.data(), p.dataSize());
}
// For now, we automatically go back to sleep after TIMEVAL_WAKE_TIMEOUT
// FIXME The java code should handshake here to release wake lock
if (shouldScheduleTimeout) {
// Cancel the previous request
if (s_last_wake_timeout_info != NULL) {
s_last_wake_timeout_info->userParam = (void *)1;
}
s_last_wake_timeout_info= internalRequestTimedCallback(wakeTimeoutCallback, NULL,
&TIMEVAL_WAKE_TIMEOUT);
}
return;
error_exit:
if (shouldScheduleTimeout) {
releaseWakeLock();
}
}

这个函数处理modem从网络端接收到的各种事件，如网络信号变化，拨入的电话，收到短信等。然后传给客户进程。

3.RIL_requestTimedCallback

extern "C" void RIL_requestTimedCallback (RIL_TimedCallback callback, void *param,
const struct timeval *relativeTime) {
internalRequestTimedCallback (callback, param, relativeTime);
}

static UserCallbackInfo *internalRequestTimedCallback (RIL_TimedCallback callback, void *param,
const struct timeval *relativeTime)
{
struct timeval myRelativeTime;
UserCallbackInfo *p_info;
p_info = (UserCallbackInfo *) malloc (sizeof(UserCallbackInfo));
p_info->p_callback = callback;
p_info->userParam = param;
if (relativeTime == NULL) {
/* treat null parameter as a 0 relative time */
memset (&myRelativeTime, 0, sizeof(myRelativeTime));
} else {
/* FIXME I think event_add's tv param is really const anyway */
memcpy (&myRelativeTime, relativeTime, sizeof(myRelativeTime));
}
ril_event_set(&(p_info->event), -1, false, userTimerCallback, p_info);
ril_timer_add(&(p_info->event), &myRelativeTime);
triggerEvLoop();
return p_info;
}

RIL_RadioFunctions定义

客户端向Rild发送请求的接口，由各手机厂商实现。

hardware\ril\include\telephony\Ril.h

typedef struct {
int version; //Rild版本
RIL_RequestFunc onRequest; //AP请求接口
RIL_RadioStateRequest onStateRequest;//BP状态查询
RIL_Supports supports;
RIL_Cancel onCancel;
RIL_GetVersion getVersion;//动态库版本
} RIL_RadioFunctions;

变量定义：

static const RIL_RadioFunctions s_callbacks = {
RIL_VERSION,
onRequest,
currentState,
onSupports,
onCancel,
getVersion
};

在hardware\ril\reference-ril\reference-ril.c中实现了RIL_RadioFunctions的各个接口函数

1.onRequest

static void onRequest (int request, void *data, size_t datalen, RIL_Token t)
{
ATResponse *p_response;
int err;
LOGD("onRequest: %s", requestToString(request));
/* Ignore all requests except RIL_REQUEST_GET_SIM_STATUS
* when RADIO_STATE_UNAVAILABLE.
*/
if (sState == RADIO_STATE_UNAVAILABLE
&& request != RIL_REQUEST_GET_SIM_STATUS
) {
RIL_onRequestComplete(t, RIL_E_RADIO_NOT_AVAILABLE, NULL, 0);
return;
}
/* Ignore all non-power requests when RADIO_STATE_OFF
* (except RIL_REQUEST_GET_SIM_STATUS)
*/
if (sState == RADIO_STATE_OFF&& !(request == RIL_REQUEST_RADIO_POWER
|| request == RIL_REQUEST_GET_SIM_STATUS)
) {
RIL_onRequestComplete(t, RIL_E_RADIO_NOT_AVAILABLE, NULL, 0);
return;
}
switch (request) {
case RIL_REQUEST_GET_SIM_STATUS: {
RIL_CardStatus *p_card_status;
char *p_buffer;
int buffer_size;
int result = getCardStatus(&p_card_status);
if (result == RIL_E_SUCCESS) {
p_buffer = (char *)p_card_status;
buffer_size = sizeof(*p_card_status);
} else {
p_buffer = NULL;
buffer_size = 0;
}
RIL_onRequestComplete(t, result, p_buffer, buffer_size);
freeCardStatus(p_card_status);
break;
}
case RIL_REQUEST_GET_CURRENT_CALLS:
requestGetCurrentCalls(data, datalen, t);
break;
case RIL_REQUEST_DIAL:
requestDial(data, datalen, t);
break;
case RIL_REQUEST_HANGUP:
requestHangup(data, datalen, t);
break;
case RIL_REQUEST_HANGUP_WAITING_OR_BACKGROUND:
// 3GPP 22.030 6.5.5
// "Releases all held calls or sets User Determined User Busy
// (UDUB) for a waiting call."
at_send_command("AT+CHLD=0", NULL);
/* success or failure is ignored by the upper layer here.
it will call GET_CURRENT_CALLS and determine success that way */
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
case RIL_REQUEST_HANGUP_FOREGROUND_RESUME_BACKGROUND:
// 3GPP 22.030 6.5.5
// "Releases all active calls (if any exist) and accepts
// the other (held or waiting) call."
at_send_command("AT+CHLD=1", NULL);
/* success or failure is ignored by the upper layer here.
it will call GET_CURRENT_CALLS and determine success that way */
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
case RIL_REQUEST_SWITCH_WAITING_OR_HOLDING_AND_ACTIVE:
// 3GPP 22.030 6.5.5
// "Places all active calls (if any exist) on hold and accepts
// the other (held or waiting) call."
at_send_command("AT+CHLD=2", NULL);

#ifdef WORKAROUND_ERRONEOUS_ANSWER
s_expectAnswer = 1;
#endif /* WORKAROUND_ERRONEOUS_ANSWER */
/* success or failure is ignored by the upper layer here.
it will call GET_CURRENT_CALLS and determine success that way */
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
case RIL_REQUEST_ANSWER:
at_send_command("ATA", NULL);
#ifdef WORKAROUND_ERRONEOUS_ANSWER
s_expectAnswer = 1;
#endif /* WORKAROUND_ERRONEOUS_ANSWER */
/* success or failure is ignored by the upper layer here.
it will call GET_CURRENT_CALLS and determine success that way */
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
case RIL_REQUEST_CONFERENCE:
// 3GPP 22.030 6.5.5
// "Adds a held call to the conversation"
at_send_command("AT+CHLD=3", NULL);
/* success or failure is ignored by the upper layer here.
it will call GET_CURRENT_CALLS and determine success that way */
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
case RIL_REQUEST_UDUB:
/* user determined user busy */
/* sometimes used: ATH */
at_send_command("ATH", NULL);
/* success or failure is ignored by the upper layer here.
it will call GET_CURRENT_CALLS and determine success that way */
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
case RIL_REQUEST_SEPARATE_CONNECTION:
{
char cmd[12];
int party = ((int*)data)[0];
// Make sure that party is in a valid range.
// (Note: The Telephony middle layer imposes a range of 1 to 7.
// It's sufficient for us to just make sure it's single digit.)
if (party > 0 && party < 10) {
sprintf(cmd, "AT+CHLD=2%d", party);
at_send_command(cmd, NULL);
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
} else {
RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);
}
}
break;
case RIL_REQUEST_SIGNAL_STRENGTH:
requestSignalStrength(data, datalen, t);
break;
case RIL_REQUEST_REGISTRATION_STATE:
case RIL_REQUEST_GPRS_REGISTRATION_STATE:
requestRegistrationState(request, data, datalen, t);
break;
case RIL_REQUEST_OPERATOR:
requestOperator(data, datalen, t);
break;
case RIL_REQUEST_RADIO_POWER:
requestRadioPower(data, datalen, t);
break;
case RIL_REQUEST_DTMF: {
char c = ((char *)data)[0];
char *cmd;
asprintf(&cmd, "AT+VTS=%c", (int)c);
at_send_command(cmd, NULL);
free(cmd);
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
break;
}
case RIL_REQUEST_SEND_SMS:
requestSendSMS(data, datalen, t);
break;
case RIL_REQUEST_SETUP_DATA_CALL:
requestSetupDataCall(data, datalen, t);
break;
case RIL_REQUEST_SMS_ACKNOWLEDGE:
requestSMSAcknowledge(data, datalen, t);
break;
case RIL_REQUEST_GET_IMSI:
p_response = NULL;
err = at_send_command_numeric("AT+CIMI", &p_response);
if (err < 0 || p_response->success == 0) {
RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);
} else {
RIL_onRequestComplete(t, RIL_E_SUCCESS,
p_response->p_intermediates->line, sizeof(char *));
}
at_response_free(p_response);
break;
case RIL_REQUEST_GET_IMEI:
p_response = NULL;
err = at_send_command_numeric("AT+CGSN", &p_response);

if (err < 0 || p_response->success == 0) {
RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);
} else {
RIL_onRequestComplete(t, RIL_E_SUCCESS,
p_response->p_intermediates->line, sizeof(char *));
}
at_response_free(p_response);
break;
case RIL_REQUEST_SIM_IO:
requestSIM_IO(data,datalen,t);
break;
case RIL_REQUEST_SEND_USSD:
requestSendUSSD(data, datalen, t);
break;
case RIL_REQUEST_CANCEL_USSD:
p_response = NULL;
err = at_send_command_numeric("AT+CUSD=2", &p_response);
if (err < 0 || p_response->success == 0) {
RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);
} else {
RIL_onRequestComplete(t, RIL_E_SUCCESS,
p_response->p_intermediates->line, sizeof(char *));
}
at_response_free(p_response);
break;
case RIL_REQUEST_SET_NETWORK_SELECTION_AUTOMATIC:
at_send_command("AT+COPS=0", NULL);
break;
case RIL_REQUEST_DATA_CALL_LIST:
requestDataCallList(data, datalen, t);
break;
case RIL_REQUEST_QUERY_NETWORK_SELECTION_MODE:
requestQueryNetworkSelectionMode(data, datalen, t);
break;
case RIL_REQUEST_OEM_HOOK_RAW:
// echo back data
RIL_onRequestComplete(t, RIL_E_SUCCESS, data, datalen);
break;
case RIL_REQUEST_OEM_HOOK_STRINGS: {
int i;
const char ** cur;
LOGD("got OEM_HOOK_STRINGS: 0x%8p %lu", data, (long)datalen);
for (i = (datalen / sizeof (char *)), cur = (const char **)data ;
i > 0 ; cur++, i --) {
LOGD("> '%s'", *cur);
}
// echo back strings
RIL_onRequestComplete(t, RIL_E_SUCCESS, data, datalen);
break;
}
case RIL_REQUEST_WRITE_SMS_TO_SIM:
requestWriteSmsToSim(data, datalen, t);
break;
case RIL_REQUEST_DELETE_SMS_ON_SIM: {
char * cmd;
p_response = NULL;
asprintf(&cmd, "AT+CMGD=%d", ((int *)data)[0]);
err = at_send_command(cmd, &p_response);
free(cmd);
if (err < 0 || p_response->success == 0) {
RIL_onRequestComplete(t, RIL_E_GENERIC_FAILURE, NULL, 0);
} else {
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
}
at_response_free(p_response);
break;
}
case RIL_REQUEST_ENTER_SIM_PIN:
case RIL_REQUEST_ENTER_SIM_PUK:
case RIL_REQUEST_ENTER_SIM_PIN2:
case RIL_REQUEST_ENTER_SIM_PUK2:
case RIL_REQUEST_CHANGE_SIM_PIN:
case RIL_REQUEST_CHANGE_SIM_PIN2:
requestEnterSimPin(data, datalen, t);
break;
case RIL_REQUEST_GSM_SMS_BROADCAST_ACTIVATION:
requestSmsBroadcastActivation(0,data, datalen, t);
break;
case RIL_REQUEST_GSM_SET_BROADCAST_SMS_CONFIG:
LOGD("onRequest RIL_REQUEST_GSM_SET_BROADCAST_SMS_CONFIG");
requestSetSmsBroadcastConfig(0,data, datalen, t);
break;
case RIL_REQUEST_GSM_GET_BROADCAST_SMS_CONFIG:
requestGetSmsBroadcastConfig(0,data, datalen, t);
break;
default:
RIL_onRequestComplete(t, RIL_E_REQUEST_NOT_SUPPORTED, NULL, 0);
break;
}
}

对每一个RIL_REQUEST_XXX请求转化成相应的ATcommand，发送给modem，然后睡眠等待，当收到ATcommand的最终响应后，线程被唤醒，将响应传给客户端进程。

2.currentState

static RIL_RadioState currentState()
{
return sState;
}

3.onSupports

static int onSupports (int requestCode)
{
//@@@ todo
return 1;
}

4.onCancel

static void onCancel (RIL_Token t)
{
//@@@todo
}

5.getVersion

static const char * getVersion(void)
{
return "android reference-ril 1.0";
}

注册RIL_Env接口

由于各手机厂商的AT指令差异，因此与modem交互层需要各手机厂商实现，以动态库的形式提供。作为介于modem与上层的中间层，即要与底层交互也要与上层通信，因此就需要定义一个接口来衔接RILD与动态库，RIL_Env和RIL_RadioFunctions接口就是libril.so与librefrence.so通信的桥梁。是Rild架构中用于隔离通用代码和厂商代码的接口，RIL_Env由通用代码实现，而RIL_RadioFunctions则是由厂商代码实现。


RIL_Init的主要任务：

1. 向librefrence.so注册libril.so提供的接口RIL_Env；

2. 创建一个mainLoop工作线程，用于初始化AT模块，并监控AT模块的状态，一旦AT被关闭，则重新打开并初始化AT；

3. 当AT被打开后，mainLoop工作线程将向Rild提交一个定时事件，并触发eventLoop来完成对modem的初始化；

4. 创建一个readLoop工作线程，用于从AT串口中读取数据；

5.返回librefrence.so提供的接口RIL_RadioFunctions；

hardware\ril\reference-ril\reference-ril.c

const RIL_RadioFunctions *RIL_Init(const struct RIL_Env *env, int argc, char **argv)
{
int ret;
int fd = -1;
int opt;
pthread_attr_t attr;
　　s_rilenv = env; //将ril.cpp中定义的RIL_Env注册到reference-ril.c中的s_rilenv
while ( -1 != (opt = getopt(argc, argv, "p:d:s:"))) {
switch (opt) {
case 'p':
s_port = atoi(optarg);
if (s_port == 0) {
usage(argv[0]);
return NULL;
}
LOGI("Opening loopback port %d\n", s_port);
break;
case 'd':
s_device_path = optarg;
LOGI("Opening tty device %s\n", s_device_path);
break;
case 's':
s_device_path = optarg;
s_device_socket = 1;
LOGI("Opening socket %s\n", s_device_path);
break;
default:
usage(argv[0]);
return NULL;
}
}
if (s_port < 0 && s_device_path == NULL) {
usage(argv[0]);
return NULL;
}
pthread_attr_init (&attr);
　　pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
　　//创建一个mainLoop线程
　　ret = pthread_create(&s_tid_mainloop, &attr, mainLoop, NULL);
　　//将reference-ril.c中定义的RIL_RadioFunctions返回并注册到ril.cpp中的s_callbacks
return &s_callbacks;
}

mainLoop工作线程是用来初始化并监控AT模块的，一旦AT模块被关闭，就自动打开。

static void * mainLoop(void *param)
{
int fd;
int ret;
　　AT_DUMP("== ", "entering mainLoop()", -1 );
　　//为AT模块设置回调函数
at_set_on_reader_closed(onATReaderClosed);
at_set_on_timeout(onATTimeout);
for (;;) {
fd = -1;
while (fd < 0) {  //获得串口AT模块的设备文件描述符
if (s_port > 0) {
fd = socket_loopback_client(s_port, SOCK_STREAM);
} else if (s_device_socket) {
if (!strcmp(s_device_path, "/dev/socket/qemud")) {
/* Qemu-specific control socket */
fd = socket_local_client( "qemud",
ANDROID_SOCKET_NAMESPACE_RESERVED,SOCK_STREAM );
if (fd >= 0 ) {
char answer[2];
if ( write(fd, "gsm", 3) != 3 ||read(fd, answer, 2) != 2 ||
memcmp(answer, "OK", 2) != 0)
{
close(fd);
fd = -1;
}
}
}
else
fd = socket_local_client( s_device_path, ANDROID_SOCKET_NAMESPACE_FILESYSTEM,SOCK_STREAM );
} else if (s_device_path != NULL) {
fd = open (s_device_path, O_RDWR);
if ( fd >= 0 && !memcmp( s_device_path, "/dev/ttyS", 9 ) ) {
/* disable echo on serial ports */
struct termios ios;
tcgetattr( fd, &ios );
ios.c_lflag = 0; /* disable ECHO, ICANON, etc... */
tcsetattr( fd, TCSANOW, &ios );
}
}
if (fd < 0) {
perror ("opening AT interface. retrying...");
sleep(10);
}
}
s_closed = 0;
//打开AT模块，创建AT读取线程s_tid_reader，fd为modem设备文件句柄
ret = at_open(fd, onUnsolicited);
if (ret < 0) {
LOGE ("AT error %d on at_open\n", ret);
return 0;
}
//向Rild提交超时任务
RIL_requestTimedCallback(initializeCallback, NULL, &TIMEVAL_0);
sleep(1);
//如果AT模块被关闭，则waitForClose返回，重新打开AT，如果AT已打开，则阻塞
waitForClose();
LOGI("Re-opening after close");
}
}

1.打开AT模块

通过at_open打开文件描述符为fd的AT串口设备，并注册回调函数ATUnsolHandler

int at_open(int fd, ATUnsolHandler h)
{
int ret;
pthread_t tid;
pthread_attr_t attr;
s_fd = fd;
s_unsolHandler = h;
s_readerClosed = 0;
s_responsePrefix = NULL;
s_smsPDU = NULL;
sp_response = NULL;
/* Android power control ioctl */
#ifdef HAVE_ANDROID_OS
#ifdef OMAP_CSMI_POWER_CONTROL
ret = ioctl(fd, OMAP_CSMI_TTY_ENABLE_ACK);
if(ret == 0) {
int ack_count;
int read_count;
int old_flags;
char sync_buf[256];
old_flags = fcntl(fd, F_GETFL, 0);
fcntl(fd, F_SETFL, old_flags | O_NONBLOCK);
do {
ioctl(fd, OMAP_CSMI_TTY_READ_UNACKED, &ack_count);
read_count = 0;
do {
ret = read(fd, sync_buf, sizeof(sync_buf));
if(ret > 0)
read_count += ret;
} while(ret > 0 || (ret < 0 && errno == EINTR));
ioctl(fd, OMAP_CSMI_TTY_ACK, &ack_count);
} while(ack_count > 0 || read_count > 0);
fcntl(fd, F_SETFL, old_flags);
s_readCount = 0;
s_ackPowerIoctl = 1;
}
else
s_ackPowerIoctl = 0;
#else // OMAP_CSMI_POWER_CONTROL
s_ackPowerIoctl = 0;
#endif // OMAP_CSMI_POWER_CONTROL
#endif /*HAVE_ANDROID_OS*/
pthread_attr_init (&attr);
　　pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
　　//创建readerLoop工作线程，该线程用于从串口读取数据
ret = pthread_create(&s_tid_reader, &attr, readerLoop, &attr);
if (ret < 0) {
perror ("pthread_create");
return -1;
}
return 0;
}

2.添加定时事件RIL_requestTimedCallback

RIL_requestTimedCallback(initializeCallback, NULL, &TIMEVAL_0);

#define RIL_requestTimedCallback(a,b,c) s_rilenv->RequestTimedCallback(a,b,c)

向定时事件队列中添加一个定时事件，该事件的处理函数为initializeCallback，用于发送一些AT指令来初始化BP的modem。

3.readLoop工作线程

Read loop 解析从Modem 发过来的回应。如果遇到URC 则通过handleUnsolicited 上报的RIL_JAVA。如果是命令的应答，则通过handleFinalResponse 通知send_at_command 有应答结果。

static void *readerLoop(void *arg)
{
for (;;) {
const char * line;
line = readline();
if (line == NULL) {
break;
}
if(isSMSUnsolicited(line)) { //判断是否是SMS 通知
char *line1;
const char *line2;
line1 = strdup(line);
line2 = readline();
if (line2 == NULL) {
break;
}
if (s_unsolHandler != NULL) {
s_unsolHandler (line1, line2); //回调通知SMS
}
free(line1);
} else {
processLine(line); //处理接收到的数据，根据line中的指令调用不同的回调函数
}
#ifdef HAVE_ANDROID_OS
if (s_ackPowerIoctl > 0) {
/* acknowledge that bytes have been read and processed */
ioctl(s_fd, OMAP_CSMI_TTY_ACK, &s_readCount);
s_readCount = 0;
}
#endif /*HAVE_ANDROID_OS*/
}
onReaderClosed();
return NULL;
}

注册RIL_RadioFunctions接口

hardware\ril\libril\ril.cpp

extern "C" void RIL_register (const RIL_RadioFunctions *callbacks) {
int ret;
　　int flags;
　　//版本验证
if (callbacks == NULL || ((callbacks->version != RIL_VERSION)&& (callbacks->version < 2))) {
return;
}
if (callbacks->version < RIL_VERSION) {
LOGE ("RIL_register: upgrade RIL to version %d current version=%d",
RIL_VERSION, callbacks->version);
}
if (s_registerCalled > 0) {
LOGE("RIL_register has been called more than once. "Subsequent call ignored");
return;
　　}
//将reference-ril.c中定义的RIL_RadioFunctions注册到ril.cpp中
memcpy(&s_callbacks, callbacks, sizeof (RIL_RadioFunctions));
s_registerCalled = 1;
for (int i = 0; i < (int)NUM_ELEMS(s_commands); i++) {
assert(i == s_commands[i].requestNumber); //序号验证
}
for (int i = 0; i < (int)NUM_ELEMS(s_unsolResponses); i++) {
assert(i + RIL_UNSOL_RESPONSE_BASE== s_unsolResponses[i].requestNumber);
}
// old standalone impl wants it here.
if (s_started == 0) {
RIL_startEventLoop();
}
　　// 得到名为rild的socket句柄
　　s_fdListen = android_get_control_socket(SOCKET_NAME_RIL);
if (s_fdListen < 0) {
LOGE("Failed to get socket '" SOCKET_NAME_RIL "'");
exit(-1);
　　}
　　// 监听该socket
ret = listen(s_fdListen, 4);
if (ret < 0) {
LOGE("Failed to listen on control socket '%d': %s",s_fdListen, strerror(errno));
exit(-1);
}
/* 设置s_listen_event事件，一旦有客户端连接，即s_fdListen可读就会导致eventLoop工作线程中的select返回，因为该事件不是持久的，因此调用为listenCallback处理完后，将从watch_table移除该事件，所以Rild只支持一个客户端连接*/
　　ril_event_set (&s_listen_event, s_fdListen, false,listenCallback, NULL);
/* 添加s_listen_event事件，并触发eventLoop工作线程 */
rilEventAddWakeup (&s_listen_event);
#if 1
// 得到调试socket的句柄rild-debug
s_fdDebug = android_get_control_socket(SOCKET_NAME_RIL_DEBUG);
if (s_fdDebug < 0) {
LOGE("Failed to get socket '" SOCKET_NAME_RIL_DEBUG "' errno:%d", errno);
exit(-1);
　　}
　　//监听该socket
ret = listen(s_fdDebug, 4);
if (ret < 0) {
LOGE("Failed to listen on ril debug socket '%d': %s",s_fdDebug, strerror(errno));
exit(-1);
　　}
/* 设置s_debug_event事件 */
ril_event_set (&s_debug_event, s_fdDebug,  true,debugCallback, NULL);
/* 添加s_debug_event事件，并触发eventLoop工作线程 */
rilEventAddWakeup (&s_debug_event);
#endif
}

打开监听端口，接收来自客户端进程的命令请求，当与客户进程连接建立时调用listenCallback函数，创建单独线程监视并处理所有事件源。

1.客户端连接处理

s_listen_event事件用于处理上层客户端的socket连接，当得到socket连接请求时，eventLoop工作线程里的select返回并自动调用listenCallback回调函数进行处理：

tatic void listenCallback (int fd, short flags, void *param) {
int ret;
int err;
int is_phone_socket;
RecordStream *p_rs;
commthread_data_t *user_data = NULL;
user_data =(commthread_data_t *)malloc(sizeof(commthread_data_t));
struct sockaddr_un peeraddr;
socklen_t socklen = sizeof (peeraddr);
struct ucred creds;
socklen_t szCreds = sizeof(creds);
struct passwd *pwd = NULL;
assert (s_fdCommand < 0);
　　assert (fd == s_fdListen);
　　//接收一个客户端的连接，并将该socket连接保存在变量s_fdCommand中
s_fdCommand = accept(s_fdListen, (sockaddr *) &peeraddr, &socklen);
if (s_fdCommand < 0 ) {
LOGE("Error on accept() errno:%d", errno);
/* start listening for new connections again */
rilEventAddWakeup(&s_listen_event);
return;
}
/* 对客户端权限判断，判断是否是进程组ID为radio的进程发起的连接*/
errno = 0;
is_phone_socket = 0;
err = getsockopt(s_fdCommand, SOL_SOCKET, SO_PEERCRED, &creds, &szCreds);
if (err == 0 && szCreds > 0) {
errno = 0;
pwd = getpwuid(creds.uid);
if (pwd != NULL) {
if (strcmp(pwd->pw_name, PHONE_PROCESS) == 0) {
is_phone_socket = 1;
} else {
LOGE("RILD can't accept socket from process %s", pwd->pw_name);
}
} else {
LOGE("Error on getpwuid() errno: %d", errno);
}
} else {
LOGD("Error on getsockopt() errno: %d", errno);
}

if ( !is_phone_socket ) {
LOGE("RILD must accept socket from %s", PHONE_PROCESS);
close(s_fdCommand);
s_fdCommand = -1;
onCommandsSocketClosed();
/* start listening for new connections again */
rilEventAddWakeup(&s_listen_event);
return;
}
#if 0
if(s_dualSimMode) {
if(s_sim_num == 0) {
property_get(SIM_POWER_PROPERTY, prop,  "0");
if(!strcmp(prop, "0")) {
property_set(SIM_POWER_PROPERTY, "1");
s_callbacks.powerSIM(NULL);
}
} else if(s_sim_num == 1) {
property_get(SIM_POWER_PROPERTY1, prop,  "0");
if(!strcmp(prop, "0")) {
property_set(SIM_POWER_PROPERTY1, "1");
s_callbacks.powerSIM(NULL);
}
}
} else {
property_get(SIM_POWER_PROPERTY, prop, "0");
if(!strcmp(prop,  "0")) {
property_set(SIM_POWER_PROPERTY, "1");
s_callbacks.powerSIM(NULL);
}
}
#endif
//p_rs为RecordStream类型，它内部会分配一个缓冲区来存储客户端发送过来的数据
　　p_rs = record_stream_new(s_fdCommand, MAX_COMMAND_BYTES);
　　//添加一个针对接收到的客户端连接的处理事件，从而在eventLoop工作线程中处理该客户端的各种请求
ril_event_set (&s_commands_event, s_fdCommand, 1,processCommandsCallback, p_rs);
rilEventAddWakeup (&s_commands_event);
onNewCommandConnect();
}

2.客户端通信处理

在listenCallback中首先接收客户端的连接请求，并验证客户端的权限，同时将该客户端以事件的形式添加到eventLoop工作线程中进行监控，当该客户端有数据请求时，eventLoop工作线程从select中返回，并自动调用processCommandsCallback回调函数：

static void processCommandsCallback(int fd, short flags, void *param) {
RecordStream *p_rs;
void *p_record;
size_t recordlen;
int ret;
assert(fd == s_fdCommand);
p_rs = (RecordStream *)param;
　　for (;;) { //循环处理客户端发送过来的AT命令
　　 //读取一条AT命令
ret = record_stream_get_next(p_rs, &p_record, &recordlen);
if (ret == 0 && p_record == NULL) {
break;
} else if (ret < 0) {
break;
} else if (ret == 0) { /* && p_record != NULL */
//处理客户端发送过来的AT命令
processCommandBuffer(p_record, recordlen);
}
}
if (ret == 0 || !(errno == EAGAIN || errno == EINTR)) {
if (ret != 0) {
LOGE("error on reading command socket errno:%d\n", errno);
} else {
LOGW("EOS. Closing command socket.");
}
close(s_fdCommand);
s_fdCommand = -1;
ril_event_del(&s_commands_event);
record_stream_free(p_rs);
rilEventAddWakeup(&s_listen_event);
onCommandsSocketClosed();
}
}

通过processCommandBuffer函数来处理每一条AT命令：

static int processCommandBuffer(void *buffer, size_t buflen) {
Parcel p;
status_t status;
int32_t request;
int32_t token;
RequestInfo *pRI;
int ret;
p.setData((uint8_t *) buffer, buflen);
// status checked at end
status = p.readInt32(&request);
status = p.readInt32 (&token);
if (status != NO_ERROR) {
LOGE("invalid request block");
return 0;
}
if (request < 1 || request >= (int32_t)NUM_ELEMS(s_commands)) {
LOGE("unsupported request code %d token %d", request, token);
return 0;
}
pRI = (RequestInfo *)calloc(1, sizeof(RequestInfo));
pRI->token = token; //AT命令标号
pRI->pCI = &(s_commands[request]); //根据request找到s_commands命令数组中的指定AT命令
ret = pthread_mutex_lock(&s_pendingRequestsMutex);
assert (ret == 0);
pRI->p_next = s_pendingRequests;
s_pendingRequests = pRI;
ret = pthread_mutex_unlock(&s_pendingRequestsMutex);
　　assert (ret == 0);
　　//调用指定AT命令的dispatch函数，根据接收来自客户进程的命令和参数，调用onRequest进行处理。
pRI->pCI->dispatchFunction(p, pRI);
return 0;
}

打电话的AT命令：{RIL_REQUEST_DIAL, dispatchDial, responseVoid},

发短信的AT命令：{RIL_REQUEST_SEND_SMS, dispatchStrings, responseSMS},

3.电话拨打流程

static void dispatchDial (Parcel &p, RequestInfo *pRI) {
　　RIL_Dial dial; //RIL_Dial存储了打电话的所有信息
RIL_UUS_Info uusInfo;
int32_t sizeOfDial;
int32_t t;
.................. //初始化dial变量
　　s_callbacks.onRequest(pRI->pCI->requestNumber, &dial, sizeOfDial, pRI);
　　.................
return;
}

s_callbacks.onRequest其实就是调用RIL_RadioFunctions中的onRequest函数，该函数在前面已介绍过了。

static void onRequest (int request, void *data, size_t datalen, RIL_Token t)
{
switch (request) {
case RIL_REQUEST_DIAL:
requestDial(data, datalen, t);
break;
}
}

static void requestDial(void *data, size_t datalen, RIL_Token t)
{
RIL_Dial *p_dial;
char *cmd;
const char *clir;
int ret;
p_dial = (RIL_Dial *)data;
switch (p_dial->clir) {
case 1: clir = "I"; break; /*invocation*/
case 2: clir = "i"; break; /*suppression*/
default:
case 0: clir = ""; break; /*subscription default*/
　　}
　　//向串口发送AT指令
ret = at_send_command(cmd, NULL);
　　free(cmd);
　　//通知请求结果
RIL_onRequestComplete(t, RIL_E_SUCCESS, NULL, 0);
}

向AT发送完拨号指令后，通过RIL_onRequestComplete返回处理结果，RIL_onRequestComplete实际上是RIL_Env中的OnRequestComplete函数，在前面我们也介绍过了

extern "C" void RIL_onRequestComplete(RIL_Token t, RIL_Errno e, void *response, size_t responselen) {
RequestInfo *pRI;
int ret;
size_t errorOffset;
　　pRI = (RequestInfo *)t;
　　//该请求已经处理，需要从请求队列中移除该请求
if (!checkAndDequeueRequestInfo(pRI)) {
LOGE ("RIL_onRequestComplete: invalid RIL_Token");
return;
}
if (pRI->local > 0) {
...........
sendResponse(p);
}
done:
free(pRI);
}

static int sendResponse (Parcel &p) {
return sendResponseRaw(p.data(), p.dataSize()); //将结果发送给JAVA RIL客户端
}

static int sendResponseRaw (const void *data, size_t dataSize) {
int fd = s_fdCommand;
int ret;
uint32_t header;
if (s_fdCommand < 0) {
return -1;
}
if (dataSize > MAX_COMMAND_BYTES) {
return -1;
}
pthread_mutex_lock(&s_writeMutex);
header = htonl(dataSize);
ret = blockingWrite(fd, (void *)&header, sizeof(header));
if (ret < 0) {
pthread_mutex_unlock(&s_writeMutex);
return ret;
}
ret = blockingWrite(fd, data, dataSize);
if (ret < 0) {
pthread_mutex_unlock(&s_writeMutex);
return ret;
}
pthread_mutex_unlock(&s_writeMutex);
return 0;
}

拨打 电话的时序图如下：

Rild通过onRequest向动态库提交一个请求，然后返回，动态库处理完请求后，处理结果通过回调接口通知客户