The `socket_connect_one` function previously did an `exit(1)` when
encountering any errors with opening the socket. This would break
connecting to a host where multiple possible addrinfos are returned,
where the leading addrinfos are in fact impossible to connect to. E.g.
with a kernel configured without support for IPv6, the `getaddrinfo`
call may still return a hint containing an IPv6 address alongside
another hint with an IPv4 address. Creating the socket with the IPv6
address, which will cause an error, lead us to exiting early without
even trying remaining hints.
While one can argue that the user should have compiled without HAVE_IPV6
or used an appropriate DNS configuration, we can do better by simply
skipping over the current addrinfo causing an error. To do so, we split
out a new function `socket_connect_next`, which selects the next
available address info and subsequently calls `socket_connect_one`
again. When no hints remain, `sock_connect_one` will error out at that
point.
that's what the sources already assumed anyway. size_t is total
overkill, as No Email Ever (TM) will exceed 2GiB.
this also fixes a harmless format string warning in 32 bit builds.
if AuthMechs includes more than just LOGIN and the server announces any
AUTH= mechanism, we try SASL. but that can still fail to find any
suitable authentication mechanism, and we must not error out in that
case if we are supposed to fall back to LOGIN.
specifically, if AuthMechs included more than just LOGIN (which would be
the case for '*') and the server announced any AUTH= mechanism, we'd
immediately error out upon seeing it, thus failing to actually try
LOGIN.
the number was chosen to make queries more comprehensible when the
server sends no UIDNEXT, but it appears that such insanely large UIDs
actually show up in the wild. so send 32-bit INT_MAX instead.
note that this is again making an assumption: that no server uses
unsigned ints for UIDs. but we can't sent UINT_MAX, as that would break
with servers which use signed ints. also, *we* use signed ints (which is
actually a clear violation of the spec).
it would be possible to special-case the range [1,inf] to 1:*, thus
entirely removing arbitrary limits. however, when the range doesn't
start at 1, we may actually get a single message instead of none due to
the imap uid range limits being unordered. this gets really nasty when
we need to issue multiple queries, as we may list the same message
twice.
a reliable way around this would be issuing a separate query to find the
actual value of UID '*', to make up for the server not sending UIDNEXT
in the first place. this would obviously imply an additional round-trip
per mailbox ...
the mbsync manual says explicitly that the system's default certificate
store should *not* be specified.
however, the isync manual talked about CA certificates, which is (and
always was) exactly wrong.
also adjust both .sample rc files.
flock() may be implemented via fcntl(), which may cause the process to
deadlock itself when trying to apply both types of locks. this is the
case even on linux when the file lives on NFS.
it's unlikely that anything except mbsync would try to access the
.uidvalidity files anyway, so there is no point in trying to be
compatible with anything else ...
REFMAIL: uddy4g589ym.fsf@eismej-u14.spgear.lab.emc.com
it is legal for an email system to simply change the case of rfc2822
headers, and at least one imap server apparently does just that.
this would lead to us not finding our own header, which is obviously not
helpful.
REFMAIL: CA+fD2U3hJEszmvwBsXEpTsaWgJ2Dh373mCESM3M0kg3ZwAYjaw@mail.gmail.com
recycling server connections skips everything up to setting up the
prefix (Path/NAMESPACE). "everything" should obviously include enabling
compression, as that must be done at most once per connection.
any structures may be invalid after callback invocation.
this has the side effect that the socket write callback now returns
void, like all other callbacks do.
the synchronous writing to the socket would have typically invoked the
write callback, which would flush further commands, thus recursing.
we take the easy way out and make it fully asynchronous, i.e., no data
is sent before (re-)entering the event loop.
this also has the effect that socket_write() cannot fail any more, and
any errors will be reported asynchronously. this is consistent with
socket_read(), and produces cleaner code.
this introduces a marginal performance regression: the maildir driver is
synchronous, so all messages (which fit into memory) will be read before
any data is sent. this is not considered relevant.
in the case of imap stores, the failure is bound to the server config,
not just the store config.
that means that the storage of the failure state needs to be private to
the driver, accessible only through a function.
simply make the code symmetrical to the inverse case.
note that the result will be sort of awkward, as the folders under Path
(and thus the subfolders of Inbox) don't start with a dot, while the
subfolders of these folders do. this needs to be addressed separately.
when we run into Inbox while listing Path, check whether Inbox is being
listed anyway, and just skip it if so, instead of listing it right away
and resetting LIST_INBOX (and thus having a calling order dependency).
USER (the authorization identity) specifies whom to act for.
AUTHNAME (the authentication identity) specifies who is acting (and
thus whose PASS is being used).
USER is derived from AUTHNAME if omitted, but apparently the
GSS-API module automatically adds the REALM, which is not helpful.
it appears to be common to set both USER and AUTHNAME to the same value,
so let's just do it as well.
REFMAIL: 20150407194807.GA1714@leeloo.kyriasis.com
