Recovering MySQL root password

Have you ever dealt with different Mysql Installations on different machines?
Have you ever mixed up root passwords of different installations?

I recently had that happened to me, I decided to look further into it and find a good way to do a password reset for my root account.

Here is what we will do:

1. Stop the mysql daemon.


2. Start mysql with "--skip-grant-table" option.


3. login with your root account with no password.


4. update the mysql.users table with your new password.


5. restart the mysql default daemon.

Step1: stop the running mysql daemon

/etc/init.d/mysql stop

Output:

* Stopping MySQL database server mysqld  [ OK ]

Note: Make sure it is stopped with the following command

ps aux | grep mysql

You should see only one entry for the grep command you just typed.

Step2: we start mysql with "--skip-grant-table" option.

mysqld_safe --skip-grant-table

You should find output similar when you hit

ps aux | grep mysql7090 pts/1    S      0:00 /bin/sh /usr/bin/mysqld_safe --skip-grant-table7129 pts/1    Sl     0:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --port=3306 --socket=/var/run/mysqld/mysqld.sock --skip-grant-table7131 pts/1    S      0:00 logger -p daemon.err -t mysqld_safe -i -t mysqld7246 pts/2    S+     0:00 grep --color=auto mysql

You should login successfully without any password.

mysql -uroot

Step4: change your root password

use mysql;
update user set password=PASSWORD("NEW-ROOT-PASSWORD") where User='root';
flush privileges;
quit

/etc/init.d/mysql stop/etc/init.d/mysql start

You should be able to login normally with your new password.

Changing your home directory to a new Drive on Ubuntu

I recently was trying to install Windows with my Ubuntu on my machine. I ended up moving my /home partition to another extended one :).

Windows Vista can't be installed on an extended partition (or at least that is what it told me), so i had to make a new primary partition for it. Since I'm using 3 primary partitions for my linux (boot, root and home) plus the extended partition area. The total primary partition (and maximum you can have) is 4 primary partitions. I had to relocate one of my Linux partitions to an extended one. Either i move my boot partition, or the home partition. home was my choice so i did the following.

First you have to make a new extended partition for your home. I choose to try the reiserfs as i read it has some performance advantage over ext3. let's call it /dev/sda5.

Next, you should mount it and copy all your /home data to your new partition.

sudo mkdir /media/home_new
sudo mount -t ext3 /dev/sda6 /media/home_new

replace "sda6" with your correct drive file

Next copy your files:
Since your "/home" directory will have soft links, hard links and nested directories, normal copy "cp" will not do the job. We can use a command similar to the one in the Debian archiving directory

find . -depth -print0 | cpio --null --sparse -pvd /media/home_new

After copying the data you have to edit "/etc/fstab" to make sure your "/home" is pointing to your new partition. You may find some "UUID"s instead of "/dev/..." just replace your UUID with your new drive path "/dev/sda6" or whatever it is.

/dev/sda6  /home reiserfs relatime  0 2

I just replaced the drive file and the file system as i changed both of them. It is best to keep the rest on their default settings.

Now Restart your machine and everything should work fine.You can even create a new primary partition for your windows installation now.

Calling javascript from ActiveX component.

Recently I was trying to call javascript functions in a web page from an embeded activex component i'm working on (The same way a flex developer do using ExternalInterface).

Problems facing this kind of action:

The problem in MFC is that life is not easy like Flex in this specific point. You have to deal with alot of COM interfaces to get what you want. So my problem was as follows.

1. I should get a reference to the window that the ActiveX control is embeded in (in my case, it will be an IE tab).


2. Try to get an interface from this window to an html container to be able to access html and javascript.


3. find the javascript function you want to call.


4. formulate the parameters in the way that suits the Interface.
   
   
   
   1. Starting a normal ActiveX control application using the app wizzard, leaving all the default settings.
   
   
   2. in the ActiveXCtrl class added a CComPtr which i will be using to access the javascript functions inside the web page.
   
   
   3. Added a new method I called it FindMainWindow() and called it in the OnDraw()method.
   
   
   4. the code of FindMainWindow()Is as follows.
      

      void FindMainWindow()
      {
        LPOLECLIENTSITE lpClientSite = NULL;
        lpClientSite = GetClientSite();
        CComPtr<IServiceProvider> serviceProvider(0);
        CComPtr<IWebBrowserApp> webBrowserApp(0);
        CComPtr<IWebBrowser2> webBrowser(0);
        CComPtr<IDispatch> dispatch(0);
        if(SUCCEEDED(lpClientSite->QueryInterface(IID_IServiceProvider,(void**)&serviceProvider)))  {
        }
        if(SUCCEEDED(serviceProvider->QueryService(IID_IWebBrowserApp,IID_IWebBrowserApp,(void**)&webBrowserApp)))
        { }
        if(SUCCEEDED(webBrowserApp->QueryInterface(IID_IWebBrowser2,(void**)&webBrowser)))
        {
          webBrowser->get_Document(&dispatch);
        }
        if(SUCCEEDED(dispatch->QueryInterface(IID_IHTMLDocument2,(void**)&htmlDoc)))
        {
          LOG(_T("Found Html Document:"));
        }
      }

      
      As you can see here, I needed to get first an IServiceProvider interface from theIOLEClientSite i got by calling GetClientSite().
      The following link in the msdn documentation says in the remarks section that The IWebBrowser2 interface derives from IDispatch indirectly. IWebBrowser2 derives from IWebBrowserApp, which in turn derives from IWebBrowser, which finally derives from IDispatch. So i had to get an IWebBrowserApp interface then IWebBrowser2. Finally getting an IDispatch interface to get the IHTMLDocumtne2 from it.
   
   
   5. Here we start to call a javascript methods within the IHTMLDocument2 interface we have got earlier. we call get_script(IDispatch*) to get the script object. The following code demonstrate how to get the id of a given javascript function name, formulating the parameters and invoking the function.
      

      CComPtr spScript;
      if(!GetJScript(spScript))
      {
      return false;
      }
      CComBSTR bstrMember(function);
      DISPID dispid = NULL;
      HRESULT hr = spScript->GetIDsOfNames(IID_NULL,&bstrMember,1,LOCALE_SYSTEM_DEFAULT,&dispid);
      
      if(FAILED(hr))
      {
      return false;
      }
      
      CStringArray paramArray;
      const int arraySize = paramArray.GetSize();
      DISPPARAMS dispparams;
      memset(&dispparams, 0, sizeof dispparams);
      dispparams.cArgs = arraySize;
      dispparams.rgvarg = new VARIANT[dispparams.cArgs];
      
      for( int i = 0; i < arraySize; i++)
      {
        CComBSTR bstr = paramArray.GetAt(arraySize - 1 - i); // back reading
        bstr.CopyTo(&dispparams.rgvarg[i].bstrVal);
        dispparams.rgvarg[i].vt = VT_BSTR;
      }
      dispparams.cNamedArgs = 0;
      EXCEPINFO excepInfo;
      memset(&excepInfo, 0, sizeof excepInfo);
      CComVariant vaResult;
      UINT nArgErr = (UINT)-1;  // initialize to invalid arg
      
      hr = spScript->Invoke(dispid,IID_NULL,0,DISPATCH_METHOD,&dispparams,&vaResult,&excepInfo,&nArgErr);
      if(FAILED(hr))
      {
      return false;
      }
      *pVarResult = vaResult;
      return true;

      
      
   
   
   
   

Finally call the javascript and cross fingers!


Solution:


Here is what i succeeded in after 5 hours of searching and reading and debugging code.

I have simplified this example as it was a testing to show that javascript is called successfully.
The detailed example on calling javascript from IHTMLDocument2 can be found in this link