Linux – how to get parameters of Linux module when it is compiled NOT as a module

You can do it by using this simple one way command, which uses the /proc/modules and /sys virtual filesystems:

cat /proc/modules | cut -f 1 -d " " | while read module; do \
 echo "Module: $module"; \
 if [ -d "/sys/module/$module/parameters" ]; then \
  ls /sys/module/$module/parameters/ | while read parameter; do \
   echo -n "Parameter: $parameter --> "; \
   cat /sys/module/$module/parameters/$parameter; \
  done; \
 fi; \
 echo; \
done

You will obtain an output like this:

...
...
Module: vboxnetadp

Module: vboxnetflt

Module: vboxdrv
Parameter: force_async_tsc --> 0

Module: binfmt_misc

Module: uinput

Module: fuse
Parameter: max_user_bgreq --> 2047
Parameter: max_user_congthresh --> 2047

Module: md_mod
Parameter: new_array --> cat: /sys/module/md_mod/parameters/new_array: Permission denied
Parameter: start_dirty_degraded --> 0
Parameter: start_ro --> 0

Module: loop
Parameter: max_loop --> 0
Parameter: max_part --> 0

Module: kvm_intel
Parameter: emulate_invalid_guest_state --> N
Parameter: ept --> Y
Parameter: fasteoi --> Y
Parameter: flexpriority --> Y
Parameter: nested --> N
Parameter: ple_gap --> 0
Parameter: ple_window --> 4096
Parameter: unrestricted_guest --> Y
Parameter: vmm_exclusive --> Y
Parameter: vpid --> Y
Parameter: yield_on_hlt --> Y

Module: kvm
Parameter: allow_unsafe_assigned_interrupts --> N
Parameter: ignore_msrs --> N
Parameter: min_timer_period_us --> 500

Module: tpm_infineon

Module: joydev

Module: snd_hda_codec_hdmi
Parameter: static_hdmi_pcm --> N
...
...

Hope this helps.

Short answer: you can't. Ports below 1024 can be opened only by root. As per comment - well, you can, using CAP_NET_BIND_SERVICE, but that approach, applied to java bin will make any java program to be run with this setting, which is undesirable, if not a security risk.

The long answer: you can redirect connections on port 80 to some other port you can open as normal user.

Run as root:

# iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080

As loopback devices (like localhost) do not use the prerouting rules, if you need to use localhost, etc., add this rule as well (thanks @Francesco):

# iptables -t nat -I OUTPUT -p tcp -d 127.0.0.1 --dport 80 -j REDIRECT --to-ports 8080

NOTE: The above solution is not well suited for multi-user systems, as any user can open port 8080 (or any other high port you decide to use), thus intercepting the traffic. (Credits to CesarB).

EDIT: as per comment question - to delete the above rule:

# iptables -t nat --line-numbers -n -L

This will output something like:

Chain PREROUTING (policy ACCEPT)
num  target     prot opt source               destination         
1    REDIRECT   tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:8080 redir ports 8088
2    REDIRECT   tcp  --  0.0.0.0/0            0.0.0.0/0           tcp dpt:80 redir ports 8080

The rule you are interested in is nr. 2, so to delete it:

# iptables -t nat -D PREROUTING 2