On 07/16/14 17:31, Nehal J Wani wrote:
cmd = virCommandNew(dnsmasqCapsGetBinaryPath(caps)); virCommandAddArgFormat(cmd, "--conf-file=%s", configfile); - virCommandAddArgFormat(cmd, "--dhcp-script=%s", leaseshelper_path); + virCommandAddArgFormat(cmd, "--dhcp-script=%s", pseudo_leaseshelper_path); + virCommandAddArgFormat(cmd, "--leasefile-ro");
Does dnsmasq pass through the rest of the environment we pass to it at this point? The leaseshelper extracts quite a lot of stuff from the environment variables that are passed by dnsmasq. In case it does we could use an env variable to pass the interface name instead of linking the helper and using different names.
If I use the following line of code in the function networkBuildDhcpDaemonCommandLine ... setenv("VIR_BRIDGE_NAME", network->def->bridge, 1); .. then yes, the helper program invoked by dnsmasq does get to see this variable. (It does so in Fedora20). (Looks like I acted in haste, should've waited for more replies on RFC, sigh)
I wanted to reply to that but I was a bit busy and didn't manage to do it soon enough. We have wrappers for running a separate command with a env variable virCommandAddEnv*... you can use easily for this.
So, in the next version that I will send, should I first make a wrapper by the name virSetEnvBlockSUID for setenv, just like we have virGetEnvBlockSUID for getenv?
No, please use the API mentioned above
A second issue that comes into my mind is compatibility with already existing files. Does this work when you already have a lease file? (I didn't try it, I'm just asking).
If we use the --leasefile-ro option, then although this method will work, but no, the lease file will *not* be read/written at all. So even if an old one exists, its of no use. But then again, the use of --leasefile-ro is mandatory, so that all events are captured by our helper program. For example, renew of a lease.
My concerns are whether this will work in the case you already used the leases helper as the patch is adding a few fields to the stored format.
Regards, Nehal J Wani
Peter