POST-->BIOS-->MBR-->bootloader-->kernel-->initrd-->/sbin/init-->/etc/init.d/rcS
以linux-2.6.39内核版本为例：php
// 源码下载 wget https://mirror.tuna.tsinghua.edu.cn/kernel/v2.6/linux-2.6.39.tar.xz // 编译 make menuconfig make
生成vmlinux可执行文件，和arch/x86/boot/bzImage
bzImage是vmlinx的压缩文件，即vmlinuzlinux
// 源码下载 wget https://busybox.net/downloads/busybox-1.30.1.tar.bz2 // 编译 make menuconfig make make install
// 源码下载 wget https://uclibc.org/downloads/uClibc-0.9.33.tar.xz // 编译 make menuconfig make sudo make install
#!/bin/bash
if [ -z "$1" ]; then
echo "usage: `basename $0` dir"
exit 1
fi
if [[ $1 =~ "/dev" ]]; then
DEV_DIR=$1
else
DEV_DIR=$1/dev
fi
PRE_DIR=`pwd`
mkdir -p $DEV_DIR
cd $DEV_DIR
echo -n "make devs into $DEV_DIR ... "
# misc devs
mknod mem c 1 1
mknod kmem c 1 2
mknod null c 1 3
mknod port c 1 4
mknod zero c 1 5
mknod full c 1 7
mknod random c 1 8
mknod urandom c 1 9
mknod console c 5 1
# ttys
mknod tty c 5 0
for i in `seq 0 9`; do
mknod tty$i c 4 $i
done
# rams
for i in `seq 0 9`; do
mknod ram$i b 1 $i
done
# loops
for i in `seq 0 7`; do
mknod loop$i b 7 $i
done
# vcs
# virtual console screen devs
for i in `seq 0 9`; do
mknod vcs$i b 7 $i
done
ln -s vcs0 vcs
# vcsa
# virtual console screen attributes devs
for i in `seq 0 9`; do
mknod vcsa$i b 7 $((128 + i))
done
ln -s vcsa0 vcsa
cd $PRE_DIR
echo "done"
#!/bin/bash BUSYBOX_DIR="./busybox" UCLIBC_DIR="./uClibc" KERNEL_DIR="./linux-2.6.39" ROOTFS_DIR="./rootfs" INITRD="rootfs.gz" BASE_DIR=`pwd` rm -r $ROOTFS_DIR mkdir -p $ROOTFS_DIR # dev mkdir -p $ROOTFS_DIR/dev ./mkdevs.sh $ROOTFS_DIR # sbin bin usr/sbin usr/bin cp -r $BUSYBOX_DIR/_install/* $ROOTFS_DIR # etc cp -r $BUSYBOX_DIR/examples/bootfloppy/etc $ROOTFS_DIR cd $ROOTFS_DIR # proc mkdir proc # sys mkdir sys # init ln -s bin/busybox init # initrd echo "make initrd=$BASE_DIR/$INITRD" find . | cpio -H newc -o | gzip -9 > $BASE_DIR/$INITRD cd $BASE_DIR echo "make rootfs done."
# fs dir type options dump pass proc /proc proc defaults 0 0 sysfs /sys sysfs defaults 0 0
执行sudo ./mkrootfs.sh后，会在当前目录下产生rootfs.gz（即咱们须要的initrd.img），rootfs目录下ls以下ios
bin dev etc init proc sbin sys usr
// 源码下载 wget https://download.qemu.org/qemu-4.0.0.tar.xz // 依赖 sudo apt get install libsdl2-dev sudo apt get install libncurses5-dev sudo apt get install libncursesw5-dev // 编译 mkdir build cd build ../configure --target-list=x86_64-softmmu make sudo make install // 运行 qemu-system-x86_64 -kernel bzImage -initrd rootfs.gz -nographic -append "console=ttyS0" -s -S // 退出 Ctrl-a x
gdb调试时报错
Remote ‘g’ packet reply is too long
此问题须要下载gdb源码，修改源码编译安装。
将gdb/remote.c文件中web
if (buf_len > 2 * rsa->sizeof_g_packet)
error (_("Remote 'g' packet reply is too long: %s"), rs->buf);
更换为bash
if (buf_len > 2 * rsa->sizeof_g_packet) {
rsa->sizeof_g_packet = buf_len;
for (i = 0; i < gdbarch_num_regs (gdbarch); i++)
{
if (rsa->regs[i].pnum == -1)
continue;
if (rsa->regs[i].offset >= rsa->sizeof_g_packet)
rsa->regs[i].in_g_packet = 0;
else
rsa->regs[i].in_g_packet = 1;
}
}
// 源码下载 wget https://mirror.tuna.tsinghua.edu.cn/gnu/gdb/gdb-8.3.tar.xz // 编译 ./configure make sudo make install
安装gdb时若是报错app
WARNING: `makeinfo' is missing on your system. You should only need it if
you modified a `.texi' or `.texinfo' file, or any other file
indirectly affecting the aspect of the manual. The spurious
call might also be the consequence of using a buggy `make' (AIX,
DU, IRIX). You might want to install the `Texinfo' package or
the `GNU make' package.
需安装texinfo，如Debian/Ubuntu系统，sudo apt install texinfo便可dom
gdb调试vmlinuxssh
gdb file vmlinux target remote localhost:1234 b start_kernel b rest_init c n
// 源码下载 wget https://mirrors.edge.kernel.org/pub/linux/utils/boot/syslinux/6.xx/syslinux-6.03.tar.xz // 编译 sudo apt install nasm sudo apt install uuid-dev make
display “Welcome to linux!” default linux timeout 10 prompt 1 label linux kernel /boot/vmlinuz append initrd=/boot/initrd.img
#!/bin/bash KERNEL_DIR="./linux-2.6.39" SYSLINUX_DIR="./syslinux-6.0.3" TARGET_DIR="syslinux" TARGET="linux.iso" mkdir -p $TARGET_DIR mkdir -p $TARGET_DIR/isolinux mkdir -p $TARGET_DIR/boot cp $KERNEL_DIR/arch/x86/boot/bzImage $TARGET_DIR/boot/vmlinuz cp rootfs.gz $TARGET_DIR/boot/initrd.img cp $SYSLINUX_DIR/bios/core/isolinux.bin $TARGET_DIR/isolinux/ cp $SYSLINUX_DIR/bios/com32/elflink/ldlinux/ldlinux.c32 $TARGET_DIR/ioslinux/ #cp isolinux.cfg $TARGET_DIR/isolinux/ mkisofs -J -o $TARGET -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table $TARGET_DIR echo "mkisofs done."