extract-vmlinux 脚本分析
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作用： 被用来将linux的vmlinuz等文件解析为 vmlinux 依赖执⾏⽂件： trap readelf tr tail grep gunzip [unxz bunzip2 unlzma lzop lz4 unzstd] 依赖库： libelf-dev(readelf) 位置： usr/src/linux-headers-$(uname -r)/scripts/extract-vmlinux（wsl2没有） 使⽤： ./extract-vmlinux vmlinuz_path > vmlinux 分析如下： #!/bin/sh # shell可执行文件的路径；调试时，保证该执行文件和执行脚本的执行文件一致，否则会导致调试和执行的结果不一致 # SPDX-License-Identifier: GPL-2.0-only # ---------------------------------------------------------------------- # extract-vmlinux - Extract uncompressed vmlinux from a kernel image # # Inspired from extract-ikconfig # (c) 2009,2010 Dick Streefland <dick@streefland.net> # # (c) 2011 Corentin Chary <corentin.chary@gmail.com> # # ---------------------------------------------------------------------- check_vmlinux() { # Use readelf to check if its a valid ELF # TODO: find a better to way to check that its really vmlinux # and not just an elf # readelf -h $1 执行成功将往下走 # > /dev/null 2>&1,标准输出重定向到/dev/null,标准错误重定向到标准输出 readelf -h $1 > /dev/null 2>&1 || return 1 cat $1 exit 0 } try_decompress() { # The obscure use of the "tr" filter is to work around older versions of # "grep" that report the byte offset of the line instead of the pattern. # Try to find the header ($1) and decompress from here # grep -abo "^$2" -a 把二进制文件当作为文本文件，-b 显示匹配字符串的偏移，如：34:matche_string，-o 只显示匹配到的字符串 # tr "$1
$2" "
$2=" < "$img" 将$img 文件中的 "$1
$2" 替换为 "
$2=" for pos in `tr "$1
$2" "
$2=" < "$img" | grep -abo "^$2"` do pos=${pos%%:*} # tail -c+$pos "$img" 显示除了前$pos个字节的所有字节 tail -c+$pos "$img" | $3 > $tmp 2> /dev/null check_vmlinux $tmp done } # Check invocation: me=${0##*/} img=$1 # $#(传入参数数量) -ne(不等于，后接个整数) 1 -o(或) ！-s(文件存在并大小不为0) $img if [ $# -ne 1 -o ! -s "$img" ] then echo "Usage: $me <kernel-image>" >&2 exit 2 fi # Prepare temp files: tmp=$(mktemp /tmp/vmlinux-XXX) # 接收到0信号(退出，定义在signal.h)，将执行"rm -f $tmp" trap "rm -f $tmp" 0 # That didnt work, so retry after decompression. try_decompress 37213 10 xy gunzip try_decompress 3757zXZ 00 abcde unxz try_decompress BZh xy bunzip2 try_decompress 135 xxx unlzma try_decompress 211114132 xy lzop -d try_decompress 02!L 30 xxx lz4 -d try_decompress (265/375 xxx unzstd # Finally check for uncompressed images or objects: check_vmlinux $img # Bail out: echo "$me: Cannot find vmlinux." >&2 总结：extract-vmlinux可以在任何Linux内核下运行，和linux内核不关联
