Fix: Add check to prevent segfault

[inouekazu]

The second argument of copy_ticket_from_msg() needs to be checked, since it may be NULL.

• src/raft.c#L235

235                 become_follower(tk, NULL);

• src/raft.c#L133

130 static void become_follower(struct ticket_config *tk,
131                 struct boothc_ticket_msg *msg)
132 {
133         copy_ticket_from_msg(tk, msg);

• src/raft.c#L125

122 static void copy_ticket_from_msg(struct ticket_config *tk,
123                 struct boothc_ticket_msg *msg)
124 {
125         tk->term_expires = time(NULL) + ntohl(msg->ticket.term_valid_for);

I set the time(NULL) + tk->term_duration to tk->term_expires if msg is NULL, referring to the update_ticket_from_msg().

[dmuhamedagic]

On Fri, May 30, 2014 at 03:17:59AM -0700, Kazunori INOUE wrote:

The second argument of copy_ticket_from_msg() needs to be checked, since it may be NULL.

Right.

It'd probably be better to:

if (msg)
    copy_ticket_from_msg(tk, msg);

Or in copy_ticket_from_msg():

if (!msg)
    return;

Otherwise, the function's name wouldn't really fit.

Further, the elections_end() should really be invoked with the
msg too so that followers do have up to date tickets in most
normal cases:

elections_end(tk, msg);

Could you please incorporate those changes and rebase.

I wonder if invoking elections_end() from the CANDIDATE state
in case the candidate didn't win the elections is good. I feel
that a server should get into the follower state when instructed
to do so by the leader.

Thanks!

[dmuhamedagic]

The offending call got removed here dcd6e98. This pull request is obsolete. Many thanks for reporting the issue and proposed solution.