Successful or Fail login process in Linux
When the Linux system boots up you get a console similar to below, machine_name login: This prompt is generated by a program called getty which is regenerated every time when an incorrect password is provided, by the init process which is again created by fork function. NOTE: Fork is a function which creates a new process by duplicating the calling process. The new process, referred to as the child, is an exact duplicate of the calling process, referred to as the parent. To be brief the Linux login works as per the below steps Getty process presents the login prompt to the user console Once the username is provided, the password is validated and if successful the user is allowed to login into the shell If there is a failure getty process is re-initiated by the fork function and the password prompt re-appears. The maximum number of failure attempts would be allowed as defined under the pam configuration. Eventually once the maximum no. of failure att