Run this as one process:
#!/bin/sh
while [ 1 = 1 ]; do
iptables -t mangle -F chain1
iptables -t mangle -X chain1
iptables -t mangle -N chain1 || exit 1
done
Run this as another process:
#!/bin/sh
while [ 1 = 1 ]; do
iptables -t mangle -F chain2
iptables -t mangle -X chain2
iptables -t mangle -N chain2 || exit 1
done
and you get:
iptables: No chain/target/match by that name
iptables: No chain/target/match by that name
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Chain already exists
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables: Unknown error 4294967295
iptables v1.3.5: can''t initialize iptables table `mangle'': Bad
file descriptor
Perhaps iptables or your kernel needs to be upgraded.
<... etc>
I''m don''t understand the things going on under the surface, so
maybe there is
a reason it''s impossible to have some kind of locking to prevent this,
like
for example, with chmod:
#!/bin/sh
while [ 1 = 1 ]; do
chmod 777 mod_me
done
#!/bin/sh
while [ 1 = 1 ]; do
chmod 666 mod_me
done
(no errors)
