日常瑣碎事

"ifconfig [dev_name] up"
int interface_up(char * interface_name)
{
    int s;
    if((s = socket(PF_INET,SOCK_STREAM,0)) < 0)
    {
        perror("Socket");
        return -1;
    }
    struct ifreq ifr;
    strcpy(ifr.ifr_name,interface_name);
    short flag;
    flag = IFF_UP;
    if(ioctl(s,SIOCGIFFLAGS,&ifr) < 0)
    {
        perror("ioctl");
        return -1;
    }
    ifr.ifr_ifru.ifru_flags |= flag;
    if(ioctl(s,SIOCSIFFLAGS,&ifr) < 0)
    {
        perror("ioctl");
        return -1;
    }
    return 0;
}

The Internet Protocol (IP) is the heart of the Linux messaging system. While Linux (more or less) strictly adheres to the layering concept - and it is possible to use a different protocol (like ATM) - IP is almost always the nexus through which packets flow. The IP implementation of the network layer performs routing and forwarding as well as encapsulating data. See Figure 2.1 for a simplified diagram of how network packets move through the Linux kernel.
 

Sited from Vbird
----------------------------------------------------
awk 則比較傾向於一行當中分成數個『欄位』來處理

Static link:
Compiler時，
library加入程式碼

[轉貼]用GCC自製Library

引用: PTT看板: LinuxDev (作者: cole945)

MediaTek真的頗累  
或者說裡面的人還滿厲害的
也可以說我太弱了orz
希望可以趕快進入狀況

What is callback?
簡單的說，如果你使用了某個function，那麼你就是『call』了一個function。
如果系統或是函式是要求你給一個function pointer，
這個function pointer指到一個實際的函式(多半這個函式是你自己寫的)。
然後它會在適當的時間呼叫此function，則此function就是所謂的 callback function。
因為這個function是被『callback』了。

Support blocking Send/Recv
作法：
socket 動態建立，傳送一次就必須建立server and client
 

Native C applications for Android
The Android Java SDK is nice and all, but what if you want to run
some C service or code? Well, it turns out that this isn't exactly
difficult. You can compile an application using a standard Linux
cross-compiler, install it and run your programs from the shell.
You will need a cross-compiler
(make sure you get the ARM GNU/Linux target). Then you can just create your program, compile, and upload to
the device:
$ arm-none-linux-gnueabi-gcc -static hello.c -o hello
$ adb push hello/hello data/hello
You can then simply run you application:
$ adb shell data/hello
Hello, Android!
Now of course, this doesn't at all explain how to tie into the graphics or the
rest of the system, but that is left as an exercise for the reader ;)
Update: My instructions were missing the essential
-static part!

Compile Android kernel from the source
I confirmed the following procedure only on my linux host (FC8). Sorry for Windows and Mac users.
1. Get toolchains from CodeSourcery (Choose ARM GNU/Linux and IA32 GNU/Linux).
2. Get kernl source code from here.
3. Deploy toolcains and kernel source and enter in the kernel source tree.