How to check if a file is locked by another process and keep checking for specified amount of time?
I am trying to create a simple way for apps to check if a file is locked by another process before locking it themselves and reading/writing to it.
what is the simplest way to achieve this? Some nice-to-haves:
- See the name of the process that is locking it
- See how long the file has been locked for (is this possible?)
- Specify an amount of time/number of tries to check the lock
I've seen mentions of creating a separate file that can act as a "lock" file, i.e. if it exists it means the original file is locked, and having the process doing the locking delete the lock file when it's finished. This seems overly complicated. In my head it should be as simple as just having a using statement on a filestream with FileShare set to None. If it doesn't throw an exception, then it is not locked. But I guess if I want to see how long a file has been locked for then I might need to write that information somewhere (like the "lock" file).
Any tips would be greatly appreciated
6 Replies
You can often find what process holds a lock, see https://stackoverflow.com/questions/317071/how-do-i-find-out-which-process-is-locking-a-file-using-net. Noone tracks how long a lock has been held, so you're on your own there
Stack Overflow
How do I find out which process is locking a file using .NET?
I've seen several of answers about using Handle or Process Monitor, but I would like to be able to find out in my own code (C#)
which process is locking a file.
I have a nasty feeling that I'm goin...
note that there's no crossplatform api for it
hmm looks like keeping a simple text file as the locking mechanism might be best then I can write date opened, who opened it, etc.
Note that just having a text file isn't enough: you need to handle toctou races, and the case where an application is closed without being able to remove the text file.
What do you mean by toctou race? Do you have an example by chance
Google it - there's a wiki article