mount drive in VirtualBox linux

prerequisites

Assume local Shared Folder: sfolder; VM mount: /home/<user>/vfolder

Insert Guest Additions CD Image
sudo apt-get install virtualbox-guest-dkms
sudo apt-get install virtualbox-guest-utils

cd /opt/VBoxGuestAdditions-*/init  

sudo ./vboxadd setup

touch ~/vfolder
chmod 777 ~/vfolder

sudo vim /etc/modules 
=>
vboxsf

mount the local Shared Folder

sudo vim /etc/fstab 
=>
sfolder /home/<user>/vfolder vboxsf defaults 0 0

mount the network Windows Shared Folder

cifs

//[localip]/[folder] /mnt/[localfolder] cifs credentials=/XXXX/.credentials,vers=3.0,iocharset=utf8,file_mode=0777,dir_mode=0777,uid=[USERNAME],gid=[USERNAME],nofail,sec=ntlmssp       0       0

[linux] changes

Duplicating your current config

cp /boot/config-`uname -r`* .config

Making the default config

make defconfig

Change a module

vim drivers/net/ethernet/intel/e1000e/netdev.c

=>

......

struct e1000_hw *hw;

printk(KERN_ALERT "DEBUG: Passed %s %d \n",__FUNCTION__,__LINE__);

Compile a kernel

make M=drivers/usb/serial -j8 # Build only a portion of the kernel with 4 core CPU
lscpu # check how many core the pc has
make -j8 # Build entire kernell with 4 core CPU

make localmodconfig

Build kernel

make -JX

Run on QEMU

qemu-system-x86_64 -no-kvm -kernel arch/x86/boot/bzImage -hda /dev/zero -append "root=/dev/zero console=ttyS0" -serial stdio -display none

Install a kernel

sudo make install

Build a module 

make modules SUBDIRS=drivers/the_module_directory

Install a module

sudo make modules_install SUBDIRS=drivers/the_module_directory

OR (if the driver installed as a module, just recompile it)

make drivers/usb/host/xhci-hcd.ko

Reload the module

sudo rmmod xhci-hcd && sudo insmod drivers/usb/host/xhci-hcd.ko

Remove kernel from boot

sudo rm -rf /lib/modules/3.3.7*

sudo rm -rf /usr/lib/modules/$(uname -r)

/boot

/lib/modules

update-grub

Remove kernel from grab

Now I understand the difference between an updated kernel and install and compile a kernel. I compiled all this kernel and the solution to delete was:

I went to nautilus as root sudo nautilus and just deleted:

/boot/vmlinuz "kernel I want to delete"

/boot/initrd "kernel I want to delete"

/boot/System "kernel I want to delete"

/boot/config "kernel I want to delete"

/lib/modules "kernel I want to delete"

and updated the grub sudo update-grub2

OR

locate *5.5.0-rc6*
sudo rm /lib/modules/5.5.0-rc6+
sudo rm -rf /lib/modules/5.5.0-rc6+

Loadable Kernel Modules

list modules

lsmod

......

e1000e                249856  0

......

module info

modinfo e1000e

......

name:           e1000e

vermagic:       5.3.0-26-generic SMP mod_unload 

signat:         PKCS#7

signer:         

sig_key:        

sig_hashalgo:   md4

parm:           debug:Debug level (0=none,...,16=all) (int)

parm:           copybreak:Maximum size of packet that is copied to a new buffer on receive (uint)

parm:           TxIntDelay:Transmit Interrupt Delay (array of int)

parm:           TxAbsIntDelay:Transmit Absolute Interrupt Delay (array of int)

parm:           RxIntDelay:Receive Interrupt Delay (array of int)

parm:           RxAbsIntDelay:Receive Absolute Interrupt Delay (array of int)

parm:           InterruptThrottleRate:Interrupt Throttling Rate (array of int)

parm:           IntMode:Interrupt Mode (array of int)

parm:           SmartPowerDownEnable:Enable PHY smart power down (array of int)

parm:           KumeranLockLoss:Enable Kumeran lock loss workaround (array of int)

parm:           WriteProtectNVM:Write-protect NVM [WARNING: disabling this can lead to corrupted NVM] (array of int)

parm:           CrcStripping:Enable CRC Stripping, disable if your BMC needs the CRC (array of int)

search the module

git grep e1000e -- '*Makefile'

load module at boot

normally

sudo vim /etc/modules

=>

......

e1000e

with params

sudo vim /etc/modprobe.d/e1000e.conf

=>

option e1000e debug=11

mutt esmpt

Yahoo:

https://help.yahoo.com/kb/generate-password-sln15241.html

Under "Account Security", In "Manage app passwords"
Generate 2 passwords, one for smtp <SMTP_PASS> and one for imap <IMAP_PASS>

esmtp:
vim ~/.esmtprc

identity "name@yahoo.com"
hostname smtp.mail.yahoo.com:587
username "name@yahoo.com"
password "<SMTP_PASS>"
starttls required

mutt:

vim ~/.muttrc

set sendmail="/usr/bin/esmtp"

set envelope_from=yes

set from="NAME <name@yahoo.com>"

set use_from=yes

set edit_headers=yes

set header_cache=~/.mutt/cache/headers

set message_cachedir=~/.mutt/cache/bodies

set certificate_file=~/.mutt/certificates

set folder = "imaps://export.imap.mail.yahoo.com:993"

set spoolfile="imaps://imap.mail.yahoo.com/INBOX"

set postponed="imaps://imap.mail.yahoo.com/Drafts"

set record="imaps://imap.mail.yahoo.com/Sent"

set imap_user = 'name@yahoo.com'

set imap_pass = "<IMAP_PASS>"

set timeout = 10

Google:

mutt:

vim ~/.muttrc

set realname = "XXXXXXXX"
set from = "XXXXXXXX@gmail.com"
set use_from = yes
set envelope_from = yes
set edit_headers=yes

set smtp_url = "smtps://XXXXXXXX@gmail.com@smtp.gmail.com:465/"
set smtp_pass = "XXXXXXXX"
set imap_user = "XXXXXXXX@gmail.com"
set imap_pass = "XXXXXXXX"
set imap_keepalive = 900
set timeout = 10
set ssl_force_tls = yes
set ssl_starttls = yes

# G to get mail
bind index G imap-fetch-mail
set folder = "imaps://imap.gmail.com:993"
set spoolfile = "imaps://imap.gmail.com/INBOX"
set header_cache=~/.mutt/cache/headers
set message_cachedir=~/.mutt/cache/bodies
set certificate_file=~/.mutt/certificates
set record = ""
set postponed = "imaps://imap.gmail.com/[Gmail]/Draft"
set editor = "vim"
set charset = "utf-8"

[git] changes

https://www.youtube.com/watch?v=_uWjGagIQcs

select branch

git checkout test

git branch

delete branch (locally)

git branch -d localBranchName

build

make M=drivers/staging/comedi/

auto-check

./scripts/checkpatch.pl --file --terse drivers/staging/comedi/drivers/ssv_dnp.c

verify

git status
git diff

revert changes (before patch)

git checkout test /xx/xx/xx

commit changes

add file to commit

git add <file>
git diff --cached

revert file from commit

git reset <file>

finally

#git commit -a
git commit -s -v

view the log

git log
git show
git show --pretty=full

who're the maintainers

perl scripts/get_maintainer.pl --separator , --nokeywords --nogit --nogit-fallback --norolestats -f drivers/staging/most/aim-sound/sound.c

format the changes (save to /tmp/)

git format-patch master..test
0001-XXX-XXX-XXX-XX.patch

./scripts/get_maintainer.pl 0001-XXX-XXX-XXX-XX.patch

git format-patch -o /tmp/ HEAD^

check the format of patch mail

./scripts/get_maintainer.pl 0001-XXX...patch

send mail

git send-email --to XX@XX.XX --cc XX@XX.XX -cc ... 0001-XXX...patch

git send-email --annotate HEAD^

revert changes (after patch)

git log --oneline

14u7289ykdja (HEAD -> test) Staging: XXX: XXX: XXXXX issue

git revert 14u7289ykdja

Who wrote that line?

git blame xxxx/xxxx.c

[linux] codingstyles

Resources

https://www.youtube.com/watch?v=LLBrBBImJt4
https://gist.github.com/17twenty/8154928

codingstyles

• Use tabs (8 characters)
• 80 character line limit
• if-statement

if (error != -ENODEV) {

        foo();

        bar();} 

else {        report_error();        goto exit;}
if (error != -ENODEV)        foo();else        goto exit;

• functions

int function(int *baz){        do_something(baz);        return 0;}

vim

• modify default

vim ~/.vimrc

filetype plugin indent onsyntax on

set number
set title
set tabstop=8set softtabstop=8set shiftwidth=8set noexpandtab

• or via commands

:set tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab

• set /usr/bin/vim/basic as default editor 

sudo update-alternatives --config editor

scripts/checkpath.pl

./scripts/checkpatch.pl --file --terse drivers/staging/comedi/drivers/ssv_dnp.c

[xv6] adventure

Build & Startup

Every change has to be (re)built by

• make

Run the xv6 OS (without pop-up) by

• make qemu-nox

Or in debug mode by (cover elsewhere)

• make qemu-nox-gdb

Add Command

says, there is sample.c to be a command in xv6

• system call required?
• vi defs.h     (add forward declaration)



// proc.c
......
int             csc ( void ); 

• vi proc.c     (add function to this)

//custom process named "csc()"intcsc(){......}

• vi syscall.h  (define sys call vector)

// System call numbers #define SYS_fork    1 ......#define SYS_close  21 #define SYS_csc    22

• vi syscall.c  (connect shell and kernel by extern)

extern int sys_chdir(void);
......
extern int sys_csc(void);
......
static int (*syscalls[])(void) = {
......
[SYS_csc]     sys_csc,
};    

• vi user.h     (callable function via shell)

// system calls
......
int csc ( void );

• vi sysproc.c  (implement the method)

......
int
sys_csc ( void )
{
  return csc ();
} 

• vi usys.S     (marco to connect user call to sys call)

......SYSCALL(csc)

• vi sysfunc.h  (add sys call handler)
• put sample.c into xv6 folder

#include "types.h"......intmain(int argc, char *argv[]){  csc();  exit();}

• vi Makefile

UPROGS=\
        _cat\
        ......
        _sample\
        ......
......
EXTRA=\
        ......
        ln.c ...... sample.c ......\
        ......

• make              (Build the whole OS)

1. 
   
2. aas

Add Executable

says, step by step

• prepare C++ codes and header files
• vi example.cpp     (function)

using namespace std;
double example(double a, double b){
  return a + b;
}

• vi plus.h

#ifndef A_Hdouble example(double a, double b);#endif

• vi main.cpp    (main program)

#include <iostream>#include <stdlib.h>#include "plus.h"using namespace std;int main(int argc, char *argv[0]){  double x, y;  x = atof(argv[1]);  y = atof(argv[2]);  cout << plus(x, y) << endl;  return 0;}

• compile the codes to objects (plus.o & main.o)
• g++ -c example.cpp
• g++ -c main.cpp
• link objects to executable (plus)
• g++ -o plus example.o main.o
• execute it
• ./plus

Or, in one go

• create a Makefile
• vi Makefile

# default targetplus: example.o main.o        # target: prerequistites/dependencies        g++ -o plus example.o main.oexample.o main.o:             # prerequistites/dependencies:        g++ -c example.cpp        g++ -c main.cppclean:                        # other target        rm example.o main.o plus

Or with marco constantPROG   = plusSRCS   = example.cpp main.cppOBJS   = $(SRCS:.cpp=.o)      # replace .o to .cpp in SRCS# default target$(PROG): $(OBJS)              # target: prerequistites/dependencies        g++ -o $@ $(OBJS)$(OBJS):                      # prerequistites/dependencies:        g++ -c $*.cppclean:                        # other target        rm $(OBJS) $(PROG)

• simply use either
• make
• make plus
• to remove generated files
• make clean

g++ -o aShell aShell.cpp