From 80bcb05357a90cc9a2e21e942a2b0a53cddfa7a6 Mon Sep 17 00:00:00 2001 From: Serge Hallyn Date: Tue, 3 Sep 2013 08:08:39 -0500 Subject: [PATCH] lxc-commands: add a comment explaining CMD_* rules MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We wish to ensure that, henceforth, newer lxc tools are always compatible with older lxc monitors. Add a comment to commands.c to explain the rule we wish to enforce to this end. Signed-off-by: Serge Hallyn Acked-by: Stéphane Graber --- src/lxc/commands.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/lxc/commands.c b/src/lxc/commands.c index a7981ba60..aad376ac8 100644 --- a/src/lxc/commands.c +++ b/src/lxc/commands.c @@ -59,6 +59,16 @@ * Each command is wrapped in a ancillary message in order to pass * a credential making possible to the server to check if the client * is allowed to ask for this command or not. + * + * IMPORTANTLY: Note that semantics for current commands are fixed. If you + * wish to make any changes to how, say, LXC_CMD_GET_CONFIG_ITEM works by + * adding information to the end of cmd.data, then you must introduce a new + * LXC_CMD_GET_CONFIG_ITEM_V2 define with a new number. You may wish to + * also mark LXC_CMD_GET_CONFIG_ITEM deprecated in commands.h. + * + * This is necessary in order to avoid having a newly compiled lxc command + * communicating with a running (old) monitor from crashing the running + * container. */ lxc_log_define(lxc_commands, lxc);