adb 源码分析 adb shell篇

标 题: adb 源码分析 adb shell篇
作 者: Y4ng
时 间: 2012-11-01 14:05:30 星期五
链 接: http://www.cnblogs.com/Y4ng/p/adb_shell.html

 

/* int adb_commandline(int argc, char **argv) */
 
if(!strcmp(argv[0], "shell") || !strcmp(argv[0], "hell"))
 
..................
 
 if(argc < 2) {
     D("starting interactive shell\n");
     r = interactive_shell();
     if (h) {
         printf("\x1b[0m");
         fflush(stdout);
     }
     return r;
 }

 

int interactive_shell(void)
{
    adb_thread_t thr;
    int fdi, fd;
    int *fds;
 
    fd = adb_connect("shell:");
    if(fd < 0) {
        fprintf(stderr,"error: %s\n", adb_error());
        return 1;
    }
    fdi = 0; //dup(0);
 
    fds = (int *)malloc(sizeof(int) * 2);
    fds[0] = fd;
    fds[1] = fdi;
 
#ifdef HAVE_TERMIO_H
    stdin_raw_init(fdi);
#endif
    adb_thread_create(&thr, stdin_read_thread, fds);    /* 开启一个从控制台接收命令的线程 */
    read_and_dump(fd);                                  /* 主态模式读取由adb服务端发送过来的数据 */
#ifdef HAVE_TERMIO_H
    stdin_raw_restore(fdi);
#endif
    return 0;
}

static void *stdin_read_thread(void *x)
{
    int fd, fdi;
    unsigned char buf[1024];
    int r, n;
    int state = 0;
 
    int *fds = (int*) x;
    fd = fds[0];
    fdi = fds[1];
    free(fds);
 
    for(;;) {
        /* fdi is really the client's stdin, so use read, not adb_read here */
        D("stdin_read_thread(): pre unix_read(fdi=%d,...)\n", fdi);
        r = unix_read(fdi, buf, 1024);  /*控制台命令读取*/
        D("stdin_read_thread(): post unix_read(fdi=%d,...)\n", fdi);
        if(r == 0) break;
        if(r < 0) {
            if(errno == EINTR) continue;
            break;
        }
        for(n = 0; n < r; n++){
            switch(buf[n]) {
            case '\n':
                state = 1;
                break;
            case '\r':
                state = 1;
                break;
            case '~':
                if(state == 1) state++;
                break;
            case '.':
                if(state == 2) {
                    fprintf(stderr,"\n* disconnect *\n");
#ifdef HAVE_TERMIO_H
                    stdin_raw_restore(fdi);
#endif
                    exit(0);
                }
            default:
                state = 0;
            }
        }
        r = adb_write(fd, buf, r);      /* 将收到的命令发送到adb服务端 */
        if(r <= 0) {
            break;
        }
    }
    return 0;
}

static void read_and_dump(int fd)
{
    char buf[4096];
    int len;
 
    while(fd >= 0) {
        D("read_and_dump(): pre adb_read(fd=%d)\n", fd);
        len = adb_read(fd, buf, 4096);              /* shell: 模式下 adb客户端的recv 会一直等待数据*/
        D("read_and_dump(): post adb_read(fd=%d): len=%d\n", fd, len);
        if(len == 0) {
        /*直到adb服务端shutdown，会收到一个长度为 0 的数据才会退出循环, 优雅的退出*/
            break;
        }
 
        if(len < 0) {
            if(errno == EINTR) continue;
            break;
        }
        fwrite(buf, 1, len, stdout);
        fflush(stdout);
    }
}