mm busybox on android tree

寫過一篇 cross compile busybox for android，因為剛剛看到一篇mm busybox on android tree，覺得不錯就貼上來。(註：編譯出來的檔案會小很多)

基本上相當簡單，照底下的做就行了....

• cd $ANDROID/external/
• git clone https://github.com/CyanogenMod/android_external_busybox.git --branch ics
• cd android_external_busybox
• mm

希望您能一切順利。這邊要提醒的是，這個 android_external_busybox 因為跟 android bionic 有很大的相關性，因此您得切換到與您的 android 版本相關的分支才行

若比對 gingerbread 與 ics 的差異...

• Android.mk: BIONIC_ICS := false --> BIONIC_ICS := true
• networking/nslookup.c: # define _res _nres  --> # define _res (*__res_get_state())
  這個變動若您在 android 需要寫程式對 dns 有需求的話，可能會遇到問題，請見這篇
• util-linux/dmesg.c: 加了底下這些，不影響大局:
  

  diff -ruN busybox-gingerbread//util-linux/dmesg.c busybox-ics/util-linux/dmesg.c
  --- busybox-gingerbread//util-linux/dmesg.c     2012-01-19 17:23:20.415785436 +0800
  +++ busybox-ics/util-linux/dmesg.c      2012-01-19 17:10:43.165785088 +0800
  @@ -10,16 +10,24 @@
    */
  
   //usage:#define dmesg_trivial_usage
  -//usage:       "[-c] [-n LEVEL] [-s SIZE]"
  +//usage:       "[-c] [-n LEVEL] [-r] [-s SIZE] [-C]"
   //usage:#define dmesg_full_usage "\n\n"
   //usage:       "Print or control the kernel ring buffer\n"
   //usage:     "\n       -c              Clear ring buffer after printing"
   //usage:     "\n       -n LEVEL        Set console logging level"
  +//usage:     "\n       -r              Show level prefix"
   //usage:     "\n       -s SIZE         Buffer size"
  +//usage:     "\n       -C              Colored output"
  
   #include 
   #include "libbb.h"
  
  +#define COLOR_DEFAULT 0
  +#define COLOR_WHITE   231
  +#define COLOR_YELLOW  226
  +#define COLOR_ORANGE  166
  +#define COLOR_RED     196
  +
   int dmesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
   int dmesg_main(int argc UNUSED_PARAM, char **argv)
   {
  @@ -29,11 +37,13 @@
          enum { 
                  OPT_c = 1 << 0,
                  OPT_s = 1 << 1,
  -               OPT_n = 1 << 2
  +               OPT_n = 1 << 2,
  +               OPT_r = 1 << 3,
  +               OPT_C = 1 << 4
          };
  
          opt_complementary = "s+:n+"; /* numeric */
  -       opts = getopt32(argv, "cs:n:", &len, &level);
  +       opts = getopt32(argv, "cs:n:rC", &len, &level);
          if (opts & OPT_n) {
                  if (klogctl(8, NULL, (long) level))
                          bb_perror_msg_and_die("klogctl");
  @@ -55,13 +65,37 @@
                  return EXIT_SUCCESS;
  
  
  -       if (ENABLE_FEATURE_DMESG_PRETTY) {
  +       if ((ENABLE_FEATURE_DMESG_PRETTY || (opts & OPT_C)) && !(opts & OPT_r)) {
                  int last = '\n';
  -               int in = 0;
  +               int in = 0, l, color;
  +               char pfx[16], *lvl;
  
                  /* Skip <#> at the start of lines */
                  while (1) {
                          if (last == '\n' && buf[in] == '<') {
  +                               if (opts & OPT_C) {
  +                                       lvl = buf + in + 1;
  +                                       sscanf(lvl, "%d", &level);
  +
  +                                       switch (level) {
  +                                       case 1:
  +                                       case 2:
  +                                       case 3: color = COLOR_RED;    break;
  +                                       case 4: color = COLOR_ORANGE; break;
  +                                       case 5: color = COLOR_YELLOW; break;
  +                                       case 7: color = COLOR_WHITE;  break;
  +                                       case 6: // common dmesg info
  +                                       default: color = COLOR_DEFAULT;
  +                                       }
  +
  +                                       if (color != COLOR_DEFAULT)
  +                                               l = sprintf(pfx, "%c[%d;%d;%dm",
  +                                                       0x1B, 38, 5, color);
  +                                       else
  +                                               l = sprintf(pfx, "%c[%dm", 0x1B, 0);
  +
  +                                       full_write(STDOUT_FILENO, pfx, l);
  +                               }
                                  in += 3;
                                  if (in >= len)
                                          break;
  @@ -72,9 +106,17 @@
                          if (in >= len)
                                  break;
                  }
  +
  +               if (opts & OPT_C) {
  +                       /* Reset default terminal color */
  +                       l = sprintf(pfx, "%c[%dm", 0x1B, 0);
  +                       full_write(STDOUT_FILENO, pfx, l);
  +               }
  +
                  /* Make sure we end with a newline */
                  if (last != '\n')
                          bb_putchar('\n');
  +
          } else {
                  full_write(STDOUT_FILENO, buf, len);
                  if (buf[len-1] != '\n')