Debug device or resource is busy, errno msg

[omronz]

Hai

Im trying to open a file which is a character special type, which is also relates to a device file stored in /dev. When i try to open the file using function open(), the errno msg reply as "Device or Resource busy". how can I debug this, meaning how can I see what application or other resource that is using that device and I want to disable it as well, to make the device only talk with my application. Previously I have change the group and owner to the dev file as root root but still this problem still exist. Can anyone help?

[WuNMOjTIQanXWBcH]

Answer:

Im trying to open a file which is a character special type, which is also relates to a device file stored in /dev. When i try to open the file using function open(), the errno msg reply as "Device or Resource busy". […] how can I see what application or other resource that is using that device […]

You might be looking for the program «lsof»¹, because

$> man lsof
[…]
NAME
       lsof - list open files
[…]
DESCRIPTION
       Lsof revision 4.81 lists on its standard output file information about files opened by processes for the following UNIX dialects:
[…]
       An open file may be a regular file, a directory, a block special file, a character special file, an executing text reference, a library, a stream or a network file (Internet
       socket, NFS file or UNIX domain socket.)  A specific file or all the files in a file system may be selected by path.
[…]

Footnotes:

1. • lsof - Wikipedia, the free encyclopedia
   • freshmeat.net: Project details for lsof
   • lsof(8): open files - Linux man page

[omronz]

Yes, that solves my problem. Thanks a lot. Really appreciate it.