linux – 为什么我的initrd只有一个目录,即’kernel’？

我正在使用debian live-build来处理可启动系统.在该过程结束时,我获得了用于引导实时系统的典型文件：squashfs文件,一些GRUB模块和配置文件以及initrd.img文件.

我可以使用这些文件启动,将initrd传递给内核

initrd=/path/to/my/initrd.img

在bootloader命令行上.但是,当我尝试检查我的initrd图像的内容时,如下所示：

$file initrd.img
initrd.img: ASCII cpio archive (SVR4 with no CRC)
$mkdir initTree && cd initTree
$cpio -idv < ../initrd.img

我得到的文件树看起来像这样：

$tree --charset=ASCII
.
`-- kernel
    `-- x86
        `-- microcode
            `-- GenuineIntel.bin

实际的文件系统树在哪里,典型的/ bin,/ etc,/ sbin …包含引导期间使用的实际文件？

解决方法:

给出的cpio块跳过方法不能可靠地工作.那是因为我自己获得的initrd图像没有在512字节边界上连接两个存档.

相反,这样做：

apt-get install binwalk
legolas [mc]# binwalk initrd.img 
DECIMAL       HEXADECIMAL     DESCRIPTION
--------------------------------------------------------------------------------
0             0x0             ASCII cpio archive (SVR4 with no CRC), file name: "kernel", file name length: "0x00000007", file size: "0x00000000"
120           0x78            ASCII cpio archive (SVR4 with no CRC), file name: "kernel/x86", file name length: "0x0000000B", file size: "0x00000000"
244           0xF4            ASCII cpio archive (SVR4 with no CRC), file name: "kernel/x86/microcode", file name length: "0x00000015", file size: "0x00000000"
376           0x178           ASCII cpio archive (SVR4 with no CRC), file name: "kernel/x86/microcode/GenuineIntel.bin", file name length: "0x00000026", file size: "0x00005000"
21004         0x520C          ASCII cpio archive (SVR4 with no CRC), file name: "TRAILER!!!", file name length: "0x0000000B", file size: "0x00000000"
21136         0x5290          gzip compressed data, from Unix, last modified: Sat Feb 28 09:46:24 2015

使用不在512字节边界上的最后一个数字(21136)：

legolas [mc]# dd if=initrd.img bs=21136 skip=1 | gunzip | cpio -tdv | head
drwxr-xr-x   1 root     root            0 Feb 28 09:46 .
drwxr-xr-x   1 root     root            0 Feb 28 09:46 bin
-rwxr-xr-x   1 root     root       554424 Dec 17  2011 bin/busybox
lrwxrwxrwx   1 root     root            7 Feb 28 09:46 bin/sh -> busybox
-rwxr-xr-x   1 root     root       111288 Sep 23  2011 bin/loadkeys
-rwxr-xr-x   1 root     root         2800 Aug 19  2013 bin/cat
-rwxr-xr-x   1 root     root          856 Aug 19  2013 bin/chroot
-rwxr-xr-x   1 root     root         5224 Aug 19  2013 bin/cpio
-rwxr-xr-x   1 root     root         3936 Aug 19  2013 bin/dd
-rwxr-xr-x   1 root     root          984 Aug 19  2013 bin/dmesg

标签：linux,debian,initrd,cpio
来源： https://codeday.me/bug/20190808/1624182.html