xv6 (linux Init)

linux 설치

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Orcale VM Virtual Machine -> OS( LTS 18.04 build-essential 시에 20.04는 충돌이 난다)

 

setting

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sudo apt-get install git wget qemu

sudo apt install build-essential

git clone https://github.com/mit-pdos/xv6-public.git

sudo apt-get install gdb ( if you don't have it.. )

cd xv6-public

make qemu-nox CPUS=1

#qemu exit
Ctrl+A -> X

 

Run

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#init.c

// init: The initial user-level program

#include "types.h"
#include "stat.h"
#include "user.h"
#include "fcntl.h"

char *argv[] = { "sh", 0 };

int
main(void)
{
  int pid, wpid;

	printf(1, "...?\n");
  if(open("console", O_RDWR) < 0){
    mknod("console", 1, 1);
    open("console", O_RDWR);
  }
  dup(0);  // stdout
  dup(0);  // stderr

  for(;;){
    printf(1, "init: starting sh\n");
    # 시작 시에 여기다가 추가하여 주면 됨
    printf(1, "start by uksung kim\n");
    pid = fork();
    if(pid < 0){
      printf(1, "init: fork failed\n");
      exit();
    }
    if(pid == 0){
      exec("sh", argv);
      printf(1, "init: exec sh failed\n");
      exit();
    }
    while((wpid=wait()) >= 0 && wpid != pid)
      printf(1, "zombie!\n");
  }
}

init.c