Enumerating all the programs that can open a particular file extension

Raymond Chen November 30, 2015 Nov 30, 2015 11/30/15

Today's Little Program enumerates all the applications which are registered for a particular file extension and lets the user choose one. We then open a file with that chosen program. As always, Little Programs do little to no error checking. The Load­Handlers function shows off the meat of the program: We use SHAssoc­Enum­...

How can I append to a file and know where it got written, even if the file is being updated by multiple processes?

Raymond Chen November 27, 2015 Nov 27, 2015 11/27/15

A customer had a collection of processes, all of which are writing to a single file. Each process wants to append some data to a file and also know where the appended data was written, because the location of the appended record needed to be saved somewhere else. "We are currently using a named mutex derived from the path to the file. To add a...

Clarifying the documentation on wildcards accepted by FindFirstFile/FindFirstFileEx

Raymond Chen November 25, 2015 Nov 25, 2015 11/25/15

A customer asked for clarification in the documentation for Find­First­File and related functions, such as Find­First­File­Ex and Find­First­File­Transacted Does Find­First­File­Ex support multiple wildcards in the lpFile­Name parameter? The documentation is not clear. We are hoping to pass ...

Playing with synchroninzation barriers

Raymond Chen November 23, 2015 Nov 23, 2015 11/23/15

A synchronization barrier is a synchronization object that works like this: A synchronization barrier knows how many threads it is managing. Each thread that calls Enter­Synchronization­Barrier blocks. When the last thread enters the synchronization barrier, all threads are released. Once a thread exits the synchronization...

Investigating a problem constructing a security descriptor to deny thread-specific access rights to Everyone

Raymond Chen November 20, 2015 Nov 20, 2015 11/20/15

A customer had a question about how to set up a security access mask. How can I deny thread-specific access rights to Everyone? Specifically, I want to deny the Everyone group the following rights when I create a process: THREAD_SET_INFORMATION THREAD_SET_THREAD_TOKEN THREAD_TERMINATE PROCESS_CREATE_PROCESS PROCESS_SET_SESSION­ID ...

Stupid JavaScript debugging tricks: Abusing the conditional breakpoint

Raymond Chen November 19, 2015 Nov 19, 2015 11/19/15

Your favorite JavaScript debugger may very well have a conditional breakpoint facility, and if it does, you can abuse it to do things unrelated to conditional breakpoints. Since conditional breakpoints are based on evaluating an expression, you can use an expression with side effects, like, say, logging. The console.log...