使用Unix域套接字的IPC

Question

我有兩個不同的應用程序，其中一個必須將數據饋入另一個。 我正在使用Unix域套接字在它們之間進行通信。 客戶端掛接到套接字，檢查服務器連接，如果可用則發送數據。 服務器等待客戶端連接，只要有可用數據，它就會讀取數據並將其寫入文件。 客戶端的主要功能是：

CLIENT:
int main(int argc, char* argv[]) {

if (argc < 2) {
    printf("Usage: Operating_Mode Path_to_DAQ_dataset output_file cudaBF\n");
    printf("Operating_Mode = 0 : Real Time BF processing\nUsage: Operating_Mode output_file cudaBF\n");
    printf("Operating_Mode = 1 : Pre-recorded data BF processing\nUsage: Operating_Mode Path_to_DAQ_dataset output_file cudaBF\n");
    return 1;
}

/*******************************************/
int s, len , packetTransferCount;
struct sockaddr_un remote;

if ((s = socket(AF_UNIX,SOCK_STREAM, 0)) == -1) {
    perror("socket");
}

remote.sun_family = AF_UNIX;
strcpy(remote.sun_path, SOCKET_DISPLAY_PATH);
len = strlen(remote.sun_path) + sizeof(remote.sun_family);    
/*******************************************/

pthread_t threadBF;

struct beamRecordedArgs processParams;
processParams.dataPath = argv[2];
processParams.bfOutputFile = argv[3];

pthread_create(&threadBF,NULL,beamProcessRecorded,(void *)&processParams);

packetTransferCount = 0;
while(processStatus != COMPLETE){
if(processStatus == TRANSFER){
    printf("Checking for display...\n");
    if (connect(s, (struct sockaddr *)&remote, len) == -1) {
        printf("No display process found\n");
        processStatus = PROCESS;
}
    else{
        printf("Display process found.. Transferring packet\n");
        send(s, txPackDisp, sizeof(txPackDisp), 0);
        close(s);
        processStatus = PROCESS;
        printf("PACKETS TRANSFERRED : %d\n",++packetTransferCount);
    }
}
else{
    while(processStatus == PROCESS){
        //sleep(1);
    }
}
}

pthread_join(threadBF,NULL);

return 0;
}

對於服務器：

SERVER:
int main(void)
{

int dispSock, lenSock, packetTransferCount;
struct sockaddr_un localDisp;

if ((dispSock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
    perror("socket");
    exit(-1);
}
localDisp.sun_family = AF_UNIX;
strcpy(localDisp.sun_path, SOCKET_DISPLAY_PATH);
unlink(localDisp.sun_path);
lenSock = strlen(localDisp.sun_path) + sizeof(localDisp.sun_family);
if (bind(dispSock, (struct sockaddr *)&localDisp, lenSock) == -1) {
    perror("bind");
    exit(-1);
}
if (listen(dispSock, 5) == -1) {
    perror("listen");
    exit(-1);
}

packetTransferCount = 0;

do{
    struct sockaddr_un remoteDisp;
    int dispSockCon,dispConn;
    dispConn = sizeof(remoteDisp);

    if ((dispSockCon = accept(dispSock, (struct sockaddr *)&remoteDisp, &dispConn)) == -1) {
        perror("accept");
        exit(-1);
    }
    printf("Connected.\n");

    int status = recv(dispSockCon, &rxPack, PACKET_SIZE*sizeof(float),0);

    if (status != -1){
        FILE *fp;
        fp = fopen("bfo_sock","w");
        fwrite(rxPack, PACKET_LENGTH, sizeof(float), fp);
        fclose(fp);
    }
    else{
        printf("Error in receiving packets\n");
    }
    close(dispSockCon);
}while(1);

close(dispSock);
unlink(SOCKET_DISPLAY_PATH);
return 0;
}

我面臨的問題是，客戶端只能在連接到服務器后發送一個數據包（先啟動還是已經運行的無關緊要的問題），之后客戶端甚至根本無法檢測到服務器進程。運行和其他進程可以檢測到它。通常，一次傳輸的數據大小大約為13.3 KB。 我在終端上看到的打印輸出是：

Number of packets to be processed in BF : 60
PACKETS PROCESSED : 1
Checking for display...
Display process found.. Transferring packet
PACKETS TRANSFERRED : 1
PACKETS PROCESSED : 2
Checking for display...
No display process found
PACKETS PROCESSED : 3
Checking for display...
No display process found

如果有人可以指出我要去哪里的地方，那對我真的很有幫助，因為我對使用套接字的IPC相當陌生。

Answer 1

好吧，我在這里找到了問題。 問題是，每次我要傳輸數據包並在此之后關閉它時，都需要重新創建套接字連接。 因此，服務器的main保持不變，但是客戶端現在變為：

int main(int argc, char* argv[]) {

if (argc < 2) {
    printf("Usage: Operating_Mode Path_to_DAQ_dataset output_file cudaBF\n");
    printf("Operating_Mode = 0 : Real Time BF processing\nUsage: Operating_Mode output_file cudaBF\n");
    printf("Operating_Mode = 1 : Pre-recorded data BF processing\nUsage: Operating_Mode Path_to_DAQ_dataset output_file cudaBF\n");
    return 1;
}

int packetTransferCount;
pthread_t threadBF;

struct beamRecordedArgs processParams;
processParams.dataPath = argv[2];
processParams.bfOutputFile = argv[3];

pthread_create(&threadBF,NULL,beamProcessRecorded,(void *)&processParams);

packetTransferCount = 0;
while(processStatus != COMPLETE){
if(processStatus == TRANSFER){
/****************************************************************/ 
/*This part was outside the loop, moving it inside creates a new 
socket connector everytime I was to transfera packet and I close it before 
the loops ends */       
    int s, len;
struct sockaddr_un remote;

    if ((s = socket(AF_UNIX,SOCK_STREAM, 0)) == -1) {
    perror("socket");
}

remote.sun_family = AF_UNIX;
strcpy(remote.sun_path, SOCKET_DISPLAY_PATH);
len = strlen(remote.sun_path) + sizeof(remote.sun_family);    
/****************************************************************/  
    printf("Checking for display...\n");
    int dispConStatus = connect(s, (struct sockaddr *)&remote, len);
    if ( dispConStatus == -1) {
        printf("No display process found\n");
        processStatus = PROCESS;
    }
    else{
        printf("Display process found.. Transferring packet\n");
        send(s, txPackDisp, sizeof(txPackDisp), 0);
        processStatus = PROCESS;
        printf("PACKETS TRANSFERRED : %d\n",++packetTransferCount);
    }
    close(s);
}
else{
    while(processStatus == PROCESS){
        //sleep(1);
    }
}
}

pthread_join(threadBF,NULL);

return 0;
}