That will not work.

Consider the following:

  1. Process A wants to change the pasword file: it copies the password file to newfile-A.
  2. Process A does its edits on newfile-A
  3. Process B wants to change the pasword file: it copies the password file to newfile-B.
  4. Process A renames newfile-A to password file.
  5. Process B does its edits on newfile-B
  6. Process B renames newfile-B to password file.
Now process A's edits are wiped out.

Next to the atomic rename opeation, you will need file-locking too: but that means only one writer is allowed at the same time, hence unavailability of the server for all those waiting for the lock to be released.

CountZero

A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

In reply to Re^5: HTTPD-Password Self-Management and Recovery by CountZero
in thread HTTPD-Password Self-Management and Recovery by mhi

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