I am using a legacy lib in Perl which is leaking file descriptors (I don't have access to the C source)
I know the name of the file the code is opening, but I don't know the file descriptor. Is there any way I can determine the file descriptor so I can close it?
/proc/<pid>/fd has the file descriptors.
$ ls -l /proc/$$/fd
total 0
lrwx------ 1 ikegami pg1404028 64 Jan 12 20:26 0 -> /dev/pts/3
lrwx------ 1 ikegami pg1404028 64 Jan 12 20:26 1 -> /dev/pts/3
lrwx------ 1 ikegami pg1404028 64 Jan 12 20:26 2 -> /dev/pts/3
lrwx------ 1 ikegami pg1404028 64 Jan 12 20:26 255 -> /dev/pts/3
You can also try lsof -a -p <pid>.
$ lsof -a -p $$
lsof: WARNING: can't stat() debugfs file system /sys/kernel/debug
Output information may be incomplete.
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
bash 13841 ikegami cwd DIR 8,17 4096 12884902307 /home/ikegami
bash 13841 ikegami rtd DIR 8,1 4096 2 /
bash 13841 ikegami txt REG 8,1 959120 130675 /bin/bash
bash 13841 ikegami mem REG 8,1 52120 914147 /lib/x86_64-linux-gnu/libnss_files-2.15.so
bash 13841 ikegami mem REG 8,1 47680 914446 /lib/x86_64-linux-gnu/libnss_nis-2.15.so
bash 13841 ikegami mem REG 8,1 97248 914458 /lib/x86_64-linux-gnu/libnsl-2.15.so
bash 13841 ikegami mem REG 8,1 35680 914035 /lib/x86_64-linux-gnu/libnss_compat-2.15.so
bash 13841 ikegami mem REG 8,1 1811128 914019 /lib/x86_64-linux-gnu/libc-2.15.so
bash 13841 ikegami mem REG 8,1 14768 914453 /lib/x86_64-linux-gnu/libdl-2.15.so
bash 13841 ikegami mem REG 8,1 159200 914028 /lib/x86_64-linux-gnu/libtinfo.so.5.9
bash 13841 ikegami mem REG 8,1 149280 914450 /lib/x86_64-linux-gnu/ld-2.15.so
bash 13841 ikegami 0u CHR 136,3 0t0 6 /dev/pts/3
bash 13841 ikegami 1u CHR 136,3 0t0 6 /dev/pts/3
bash 13841 ikegami 2u CHR 136,3 0t0 6 /dev/pts/3
bash 13841 ikegami 255u CHR 136,3 0t0 6 /dev/pts/3
