Permission Denied error while killing Gmake on Windows

[Anuj Shroff]

Hello “Developers of Gmake”

 

My name is Anuj. I work as a software developer at Mathworks.

 

While working on project involving killing ‘gmake’ process on Windows, we encountered an issue that we would like to bring to your attention.

 

Our aim is to kill the gmake process along with its sub gmakes (child processes) on windows and clean up properly (which involves unlinking object files).

 

For this we created a script which would send a ‘CTRL + C’ event to the main gmake process using win32::API of Perl. When we monitor the progress, the main gmake and child gmakes are killed properly. We see that the correct signal is being propagated to the gmake process. However, the cleanup is not happening as expected. When it tries to unlink all these “obj” files, it gives a Permission denied error.

 

To understand more about it we read the source code. We found that while handling 'CTRL + C' signal gmake suspends its main thread. While the main thread is suspended, it tries to kill the child processes and clean up the files. While the files (mainly obj files) are being cleaned up (unlinked) we get the Permission denied issue as the file seems to have a lock on it. We suspect that this lock is detected by the filer that the file is still in use by the compiler which is the main thread. Hence, it gives a Permission Denied error. As the file is on the network filer this issue is much more prominent. However, when these files are created on the local drive these issues are much less visible (Not completely gone but less).

 

Please let us know if our understanding is correct and also if you are familiar with this issue.

 

Thanks

Anuj Shroff