Linux启动顺序和修改启动后执行程序

1. Linux kernel mounts the root filesystem.
2. The kernel starts the first user process /sbin/init provided by Busybox.
3. /sbin/init reads /etc/inittab (From the SDK: linux/embedded_rootfs/etc-files/inittab).
4. /etc/inittab starts the shell script /sbin/rc (From the SDK: linux/embedded_rootfs/etc-files/rc).
5. /sbin/rc mounts the kernel pseudo filesystems /proc, /dev/shm, and /dev/pts.
6. /sbin/rc brings up the loopback network device with the IP address 127.0.0.1.
7. /sbin/rc starts syslogd provided by Busybox.
8. /sbin/rc starts telnetd provided by Busybox.
9. /sbin/rc exits returning control in /sbin/init.
10. /etc/inittab tells /sbin/init to spawn an interactive shell.
11. The user interactive shell prompt appears.

修改rc文件即可设定linux自启动的程序，即启动linux后便会自己执行的程序或者shell脚步

 

static int noinline init_post(void)
{
 free_initmem();
 unlock_kernel();
 mark_rodata_ro();
 system_state = SYSTEM_RUNNING;
 numa_default_policy();

 if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
  printk(KERN_WARNING "Warning: unable to open an initial console.\n");

 (void) sys_dup(0);
 (void) sys_dup(0);

 if (ramdisk_execute_command) {
  run_init_process(ramdisk_execute_command);
  printk(KERN_WARNING "Failed to execute %s\n",
    ramdisk_execute_command);
 }

 /*
  * We try each of these until one succeeds.
  *
  * The Bourne shell can be used instead of init if we are
  * trying to recover a really broken machine.
  */
 if (execute_command) {
  run_init_process(execute_command);
  printk(KERN_WARNING "Failed to execute %s.  Attempting "
     "defaults...\n", execute_command);
 }
 run_init_process("/sbin/init");
 run_init_process("/etc/init");
 run_init_process("/bin/init");
 run_init_process("/bin/sh");

 panic("No init found.  Try passing init= option to kernel.");