gluon-mesh-vpn-core: add gluon-wan exec wrapper

gluon-wan is a sudo-like exec wrapper that switches the process group to
gluon-mesh-vpn, making it use the WAN dnsmasq rather than resolving over
the mesh.

Note that this only affects DNS at the moment. Processes running under
gluon-wan will still use the regular mesh IPv6 routing table, and not the
WAN routing table. This is not a problem for IPv4, as there is only one
IPv4 routing table.

Fixes #1575
This commit is contained in:
Matthias Schiffer 2018-11-21 12:05:07 +01:00
parent 8e3a90ff65
commit eda3aa3333
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#!/usr/bin/lua
local GROUP = 'gluon-mesh-vpn'
local grp = require 'posix.grp'
local unistd = require 'posix.unistd'
if #arg < 1 then
io.stderr:write('Usage: gluon-wan <command> ...\n')
os.exit(1)
end
local g = grp.getgrnam(GROUP)
if not g then
io.stderr:write(string.format("gluon-wan: unable to find group '%s'\n", GROUP))
os.exit(1)
end
local ok, err = unistd.setpid('g', g.gr_gid)
if ok ~= 0 then
io.stderr:write(string.format("gluon-wan: unable to change to group: %s\n", err))
os.exit(1)
end
arg[0] = arg[1]
table.remove(arg, 1)
print(arg[0], unpack(arg))
ok, err = unistd.execp(arg[0], arg)
io.stderr:write(string.format("gluon-wan: exec failed: %s\n", err))
os.exit(1)