How to delete a file in Linux where all I have is the file descriptor

Question

I have an int file descriptor that was opened earlier (via open) and I need to remove that file.

Do I really have to first get the file name and call remove? (e.g. via using the technique in Getting Filename from file descriptor in C)

Or is there some other (linux specific OK) way of doing it solely based on the file descriptor?

I have searched and the best I could find is the above answer.

Answer 1

You can use /proc to see which path an open fd is linked to, and realpath get the full path of the symlink.

# ls -l /proc/8701/fd
total 0
lr-x------ 1 root root 64 Apr 23 22:44 0 -> /dev/null
lrwx------ 1 root root 64 Apr 23 22:44 1 -> /dev/null
lrwx------ 1 root root 64 Apr 23 22:44 2 -> /dev/null
lrwx------ 1 root root 64 Apr 23 23:19 20 -> socket:[16204]
lrwx------ 1 root root 64 Apr 23 23:19 21 -> socket:[16205]
lrwx------ 1 root root 64 Apr 23 22:44 3 -> socket:[18743]
l-wx------ 1 root root 64 Apr 23 22:44 4 -> /var/lib/dhcp/dhclient-7a30dd46-5058-47aa-b71e-ff77cfbe4194-wlan0.lease
lrwx------ 1 root root 64 Apr 23 22:44 5 -> socket:[16872]
lrwx------ 1 root root 64 Apr 23 22:44 6 -> socket:[18747]