shell炸弹

shell中执行以下命令会致使操做系统崩溃：

echo c > /proc/sysrq-trigger

/proc/sysrq-trigger是一个只能写的文件，并且是只有root才有权限写。

# ll /proc/sysrq-trigger 
--w------- 1 root root 0 Feb 24 10:58 /proc/sysrq-trigger



/proc/sysrq-trigger文件各参数含义介绍

当即重启计算机      echo "b" > /proc/sysrq-trigger

当即关闭计算机      echo "o" > /proc/sysrq-trigger



导出内存分配的信息    echo "m"  > /proc/sysrq-trigger        (Outputs memory statistics to the console  输出信息在/var/log/messages中查看)

导出当前CPU寄存器信息和标志位的信息     echo "p"  > /proc/sysrq-trigger       (outputs all flags and registers to the console  输出信息在/var/log/messages中查看)

导出线程状态信息        echo "t"  > /proc/sysrq-trigger          (outputs a list of processes to the console  输出信息在/var/log/messages中查看)

故意让系统崩溃  echo "c"  > /proc/sysrq-trigger         (crashes the system without first unmounting file systems or syncing disks attached to the system)

当即从新挂载全部的文件系统               echo "s"  > /proc/sysrq-trigger     (attempts to sync disks attached to the system)

当即从新挂载全部的文件系统为只读     echo "u"  > /proc/sysrq-trigger     (attempts to unmount and remount all file systems as read-only)

dump进入uninterrupted状态的任务的信息  echo "w" > /proc/sysrq-trigger  (输出信息在/var/log/messages中查看)

此外，还有两个相似于强制注销的功能

e ---- kills all processes except init using SIGTERM

i ---- kills all processes except init using SIGKILL



sysrq.txt详见附件：

'r' - Turns off keyboard raw mode and sets it to XLATE.

'k' - Secure Access Key (SAK) Kills all programs on the current virtual
          console. NOTE: See important comments below in SAK section.

'b' - Will immediately reboot the system without syncing or unmounting
          your disks.

'o' - Will shut your system off (if configured and supported).

's' - Will attempt to sync all mounted filesystems.

'u' - Will attempt to remount all mounted filesystems read-only.

'p' - Will dump the current registers and flags to your console.

't' - Will dump a list of current tasks and their information to your
          console.

'm' - Will dump current memory info to your console.

'v' - Dumps Voyager SMP processor info to your console.

'0'-'9' - Sets the console log level, controlling which kernel messages
          will be printed to your console. ('0', for example would make
          it so that only emergency messages like PANICs or OOPSes would
          make it to your console.)

'e' - Send a SIGTERM to all processes, except for init.

'i' - Send a SIGKILL to all processes, except for init.

'l' - Send a SIGKILL to all processes, INCLUDING init. (Your system
          will be non-functional after this.)

'h' - Will display help ( actually any other key than those listed
          above will display help. but 'h' is easy to remember :-)