只有第一行从文件打印。使用叉子和管道

Question

我试图让这个打印文件的多行，空格替换为*，所有内容都翻译成大写。这应该通过管道和叉子来完成。为什么只打印第一行。

void writer(int inpipe)
{
    char read_msg[BUFFER_SIZE];
    pid_t pid;
    int fd[2];
    read(inpipe, read_msg, BUFFER_SIZE);
    printf("%s\n",read_msg);
    return;
}

void p2(int inpipe)
{
    char read_msg[BUFFER_SIZE];

    pid_t pid;
    int fd[2];
    if(pipe(fd) == -1) {
        perror("Pipe error");
        return;
    }

    pid = fork();
    if(pid<0) {  //error
        perror("Fork Failed");
        return;
    }
    else if(pid==0) { //child
        close(fd[1]);
        writer(fd[0]);
        close(fd[0]);
        return;
    }
    else {  //parent, p2()
        read(inpipe, read_msg, BUFFER_SIZE);
        int i = 0;
        while (read_msg[i] != '\0') {
            read_msg[i] = toupper(read_msg[i]);
            i++;
        }
        close(fd[0]);
        write(fd[1],read_msg,(unsigned long)(strlen(read_msg)+1));
        close(fd[1]);
    }
    return;
}

void p1(int inpipe)
{
    char read_msg[BUFFER_SIZE];

    pid_t pid;
    int fd[2];
    if(pipe(fd) == -1) {
        perror("Pipe error");
        return;
    }

    pid = fork();
    if(pid<0) {  //error
        perror("Fork Failed");
        return;
    }
    else if(pid==0) { //child
        close(fd[1]);
        p2(fd[0]);
        close(fd[0]);
        return;
    }
    else {  //parent, p1()
        read(inpipe, read_msg, BUFFER_SIZE);
        int i = 0;
        while (read_msg[i] != '\0') {
            if ((read_msg[i] == ' '))
                read_msg[i] = '*';
            i++;
        }
        //printf("%s\n",read_msg);
        close(fd[0]);
        write(fd[1],read_msg,(unsigned long)(strlen(read_msg)+1));
        close(fd[1]);
    }
    return;
}

int main(int argc, char **argv) {
    pid_t pid;
    int fd[2];

    if(pipe(fd) == -1) {
        perror("Pipe error");
        return 1;
    }
    pid = fork();
    if(argv[1] != NULL) {
        char const* const fileName = argv[1];
        FILE* file = fopen(fileName, "r");
        char line[BUFFER_SIZE];

        while (fgets(line, sizeof(line), file)){
            if(pid<0) {  //error
                perror("Fork Failed");
                return 1;
            }
            else if(pid==0) { //child
                close(fd[1]);
                p1(fd[0]);
                close(fd[0]);
            }
            else {  //parent, main(), reader
                //reading from the file and put it into the pipe[1]
                close(fd[0]);
                write(fd[1],line,strlen(line)+1);
                close(fd[1]);
            }
        }
    }
    else
        printf("No file detected.\n");

    return EXIT_SUCCESS;
}