From 5e61585d76ae77fd5e9e96ebabb57afa4d74880d Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 14:06:34 +0200 Subject: Adding upstream version 3.5.24. Signed-off-by: Daniel Baumann --- src/oqmgr/qmgr_entry.c | 391 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 391 insertions(+) create mode 100644 src/oqmgr/qmgr_entry.c (limited to 'src/oqmgr/qmgr_entry.c') diff --git a/src/oqmgr/qmgr_entry.c b/src/oqmgr/qmgr_entry.c new file mode 100644 index 0000000..5a81487 --- /dev/null +++ b/src/oqmgr/qmgr_entry.c @@ -0,0 +1,391 @@ +/*++ +/* NAME +/* qmgr_entry 3 +/* SUMMARY +/* per-site queue entries +/* SYNOPSIS +/* #include "qmgr.h" +/* +/* QMGR_ENTRY *qmgr_entry_create(queue, message) +/* QMGR_QUEUE *queue; +/* QMGR_MESSAGE *message; +/* +/* void qmgr_entry_done(entry, which) +/* QMGR_ENTRY *entry; +/* int which; +/* +/* QMGR_ENTRY *qmgr_entry_select(queue) +/* QMGR_QUEUE *queue; +/* +/* void qmgr_entry_unselect(queue, entry) +/* QMGR_QUEUE *queue; +/* QMGR_ENTRY *entry; +/* +/* void qmgr_entry_move_todo(dst, entry) +/* QMGR_QUEUE *dst; +/* QMGR_ENTRY *entry; +/* DESCRIPTION +/* These routines add/delete/manipulate per-site message +/* delivery requests. +/* +/* qmgr_entry_create() creates an entry for the named queue and +/* message, and appends the entry to the queue's todo list. +/* Filling in and cleaning up the recipients is the responsibility +/* of the caller. +/* +/* qmgr_entry_done() discards a per-site queue entry. The +/* \fIwhich\fR argument is either QMGR_QUEUE_BUSY for an entry +/* of the site's `busy' list (i.e. queue entries that have been +/* selected for actual delivery), or QMGR_QUEUE_TODO for an entry +/* of the site's `todo' list (i.e. queue entries awaiting selection +/* for actual delivery). +/* +/* qmgr_entry_done() triggers cleanup of the per-site queue when +/* the site has no pending deliveries, and the site is either +/* alive, or the site is dead and the number of in-core queues +/* exceeds a configurable limit (see qmgr_queue_done()). +/* +/* qmgr_entry_done() triggers special action when the last in-core +/* queue entry for a message is done with: either read more +/* recipients from the queue file, delete the queue file, or move +/* the queue file to the deferred queue; send bounce reports to the +/* message originator (see qmgr_active_done()). +/* +/* qmgr_entry_select() selects the next entry from the named +/* per-site queue's `todo' list for actual delivery. The entry is +/* moved to the queue's `busy' list: the list of messages being +/* delivered. +/* +/* qmgr_entry_unselect() takes the named entry off the named +/* per-site queue's `busy' list and moves it to the queue's +/* `todo' list. +/* +/* qmgr_entry_move_todo() moves the specified "todo" queue entry +/* to the specified "todo" queue. +/* DIAGNOSTICS +/* Panic: interface violations, internal inconsistencies. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include +#include +#include + +/* Utility library. */ + +#include +#include +#include +#include + +/* Global library. */ + +#include +#include /* opportunistic session caching */ + +/* Application-specific. */ + +#include "qmgr.h" + +/* qmgr_entry_select - select queue entry for delivery */ + +QMGR_ENTRY *qmgr_entry_select(QMGR_QUEUE *queue) +{ + const char *myname = "qmgr_entry_select"; + QMGR_ENTRY *entry; + + if ((entry = queue->todo.prev) != 0) { + QMGR_LIST_UNLINK(queue->todo, QMGR_ENTRY *, entry); + queue->todo_refcount--; + QMGR_LIST_APPEND(queue->busy, entry); + queue->busy_refcount++; + + /* + * With opportunistic session caching, the delivery agent must not + * only 1) save a session upon completion, but also 2) reuse a cached + * session upon the next delivery request. In order to not miss out + * on 2), we have to make caching sticky or else we get silly + * behavior when the in-memory queue drains. Specifically, new + * connections must not be made as long as cached connections exist. + * + * Safety: don't enable opportunistic session caching unless the queue + * manager is able to schedule concurrent or back-to-back deliveries + * (we need to recognize back-to-back deliveries for transports with + * concurrency 1). + * + * If caching has previously been enabled, but is not now, fetch any + * existing entries from the cache, but don't add new ones. + */ +#define CONCURRENT_OR_BACK_TO_BACK_DELIVERY() \ + (queue->busy_refcount > 1 || BACK_TO_BACK_DELIVERY()) + +#define BACK_TO_BACK_DELIVERY() \ + (queue->last_done + 1 >= event_time()) + + /* + * Turn on session caching after we get up to speed. Don't enable + * session caching just because we have concurrent deliveries. This + * prevents unnecessary session caching when we have a burst of mail + * <= the initial concurrency limit. + */ + if ((queue->dflags & DEL_REQ_FLAG_CONN_STORE) == 0) { + if (BACK_TO_BACK_DELIVERY()) { + if (msg_verbose) + msg_info("%s: allowing on-demand session caching for %s", + myname, queue->name); + queue->dflags |= DEL_REQ_FLAG_CONN_MASK; + } + } + + /* + * Turn off session caching when concurrency drops and we're running + * out of steam. This is what prevents from turning off session + * caching too early, and from making new connections while old ones + * are still cached. + */ + else { + if (!CONCURRENT_OR_BACK_TO_BACK_DELIVERY()) { + if (msg_verbose) + msg_info("%s: disallowing on-demand session caching for %s", + myname, queue->name); + queue->dflags &= ~DEL_REQ_FLAG_CONN_STORE; + } + } + } + return (entry); +} + +/* qmgr_entry_unselect - unselect queue entry for delivery */ + +void qmgr_entry_unselect(QMGR_QUEUE *queue, QMGR_ENTRY *entry) +{ + QMGR_LIST_UNLINK(queue->busy, QMGR_ENTRY *, entry); + queue->busy_refcount--; + QMGR_LIST_APPEND(queue->todo, entry); + queue->todo_refcount++; +} + +/* qmgr_entry_move_todo - move entry between todo queues */ + +void qmgr_entry_move_todo(QMGR_QUEUE *dst, QMGR_ENTRY *entry) +{ + const char *myname = "qmgr_entry_move_todo"; + QMGR_MESSAGE *message = entry->message; + QMGR_QUEUE *src = entry->queue; + QMGR_ENTRY *new_entry; + + if (entry->stream != 0) + msg_panic("%s: queue %s entry is busy", myname, src->name); + if (QMGR_QUEUE_THROTTLED(dst)) + msg_panic("%s: destination queue %s is throttled", myname, dst->name); + if (QMGR_TRANSPORT_THROTTLED(dst->transport)) + msg_panic("%s: destination transport %s is throttled", + myname, dst->transport->name); + + /* + * Create new entry, swap the recipients between the old and new entries, + * then dispose of the old entry. This gives us any end-game actions that + * are implemented by qmgr_entry_done(), so we don't have to duplicate + * those actions here. + * + * XXX This does not enforce the per-entry recipient limit, but that is not + * a problem as long as qmgr_entry_move_todo() is called only to bounce + * or defer mail. + */ + new_entry = qmgr_entry_create(dst, message); + recipient_list_swap(&entry->rcpt_list, &new_entry->rcpt_list); + qmgr_entry_done(entry, QMGR_QUEUE_TODO); +} + +/* qmgr_entry_done - dispose of queue entry */ + +void qmgr_entry_done(QMGR_ENTRY *entry, int which) +{ + const char *myname = "qmgr_entry_done"; + QMGR_QUEUE *queue = entry->queue; + QMGR_MESSAGE *message = entry->message; + QMGR_TRANSPORT *transport = queue->transport; + + /* + * Take this entry off the in-core queue. + */ + if (entry->stream != 0) + msg_panic("%s: file is open", myname); + if (which == QMGR_QUEUE_BUSY) { + QMGR_LIST_UNLINK(queue->busy, QMGR_ENTRY *, entry); + queue->busy_refcount--; + } else if (which == QMGR_QUEUE_TODO) { + QMGR_LIST_UNLINK(queue->todo, QMGR_ENTRY *, entry); + queue->todo_refcount--; + } else { + msg_panic("%s: bad queue spec: %d", myname, which); + } + + /* + * Free the recipient list and decrease the in-core recipient count + * accordingly. + */ + qmgr_recipient_count -= entry->rcpt_list.len; + recipient_list_free(&entry->rcpt_list); + + myfree((void *) entry); + + /* + * Maintain back-to-back delivery status. + */ + if (which == QMGR_QUEUE_BUSY) + queue->last_done = event_time(); + + /* + * Suspend a rate-limited queue, so that mail trickles out. + */ + if (which == QMGR_QUEUE_BUSY && transport->rate_delay > 0) { + if (queue->window > 1) + msg_panic("%s: queue %s/%s: window %d > 1 on rate-limited service", + myname, transport->name, queue->name, queue->window); + if (QMGR_QUEUE_THROTTLED(queue)) /* XXX */ + qmgr_queue_unthrottle(queue); + if (QMGR_QUEUE_READY(queue)) + qmgr_queue_suspend(queue, transport->rate_delay); + } + + /* + * When the in-core queue for this site is empty and when this site is + * not dead, discard the in-core queue. When this site is dead, but the + * number of in-core queues exceeds some threshold, get rid of this + * in-core queue anyway, in order to avoid running out of memory. + * + * See also: qmgr_entry_move_todo(). + */ + if (queue->todo.next == 0 && queue->busy.next == 0) { + if (QMGR_QUEUE_THROTTLED(queue) && qmgr_queue_count > 2 * var_qmgr_rcpt_limit) + qmgr_queue_unthrottle(queue); + if (QMGR_QUEUE_READY(queue)) + qmgr_queue_done(queue); + } + + /* + * Update the in-core message reference count. When the in-core message + * structure has no more references, dispose of the message. + * + * When the in-core recipient count falls below a threshold, and this + * message has more recipients, read more recipients now. If we read more + * recipients as soon as the recipient count falls below the in-core + * recipient limit, we do not give other messages a chance until this + * message is delivered. That's good for mailing list deliveries, bad for + * one-to-one mail. If we wait until the in-core recipient count drops + * well below the in-core recipient limit, we give other mail a chance, + * but we also allow list deliveries to become interleaved. In the worst + * case, people near the start of a mailing list get a burst of postings + * today, while people near the end of the list get that same burst of + * postings a whole day later. + */ +#define FUDGE(x) ((x) * (var_qmgr_fudge / 100.0)) + message->refcount--; + if (message->rcpt_offset > 0 + && qmgr_recipient_count < FUDGE(var_qmgr_rcpt_limit) - 100) + qmgr_message_realloc(message); + if (message->refcount == 0) + qmgr_active_done(message); +} + +/* qmgr_entry_create - create queue todo entry */ + +QMGR_ENTRY *qmgr_entry_create(QMGR_QUEUE *queue, QMGR_MESSAGE *message) +{ + QMGR_ENTRY *entry; + + /* + * Sanity check. + */ + if (QMGR_QUEUE_THROTTLED(queue)) + msg_panic("qmgr_entry_create: dead queue: %s", queue->name); + + /* + * Create the delivery request. + */ + entry = (QMGR_ENTRY *) mymalloc(sizeof(QMGR_ENTRY)); + entry->stream = 0; + entry->message = message; + recipient_list_init(&entry->rcpt_list, RCPT_LIST_INIT_QUEUE); + message->refcount++; + entry->queue = queue; + QMGR_LIST_APPEND(queue->todo, entry); + queue->todo_refcount++; + + /* + * Warn if a destination is falling behind while the active queue + * contains a non-trivial amount of single-recipient email. When a + * destination takes up more and more space in the active queue, then + * other mail will not get through and delivery performance will suffer. + * + * XXX At this point in the code, the busy reference count is still less + * than the concurrency limit (otherwise this code would not be invoked + * in the first place) so we have to make make some awkward adjustments + * below. + * + * XXX The queue length test below looks at the active queue share of an + * individual destination. This catches the case where mail for one + * destination is falling behind because it has to round-robin compete + * with many other destinations. However, Postfix will also perform + * poorly when most of the active queue is tied up by a small number of + * concurrency limited destinations. The queue length test below detects + * such conditions only indirectly. + * + * XXX This code does not detect the case that the active queue is being + * starved because incoming mail is pounding the disk. + */ + if (var_helpful_warnings && var_qmgr_clog_warn_time > 0) { + int queue_length = queue->todo_refcount + queue->busy_refcount; + time_t now; + QMGR_TRANSPORT *transport; + double active_share; + + if (queue_length > var_qmgr_active_limit / 5 + && (now = event_time()) >= queue->clog_time_to_warn) { + active_share = queue_length / (double) qmgr_message_count; + msg_warn("mail for %s is using up %d of %d active queue entries", + queue->nexthop, queue_length, qmgr_message_count); + if (active_share < 0.9) + msg_warn("this may slow down other mail deliveries"); + transport = queue->transport; + if (transport->dest_concurrency_limit > 0 + && transport->dest_concurrency_limit <= queue->busy_refcount + 1) + msg_warn("you may need to increase the main.cf %s%s from %d", + transport->name, _DEST_CON_LIMIT, + transport->dest_concurrency_limit); + else if (queue->window > var_qmgr_active_limit * active_share) + msg_warn("you may need to increase the main.cf %s from %d", + VAR_QMGR_ACT_LIMIT, var_qmgr_active_limit); + else if (queue->peers.next != queue->peers.prev) + msg_warn("you may need a separate master.cf transport for %s", + queue->nexthop); + else { + msg_warn("you may need to reduce %s connect and helo timeouts", + transport->name); + msg_warn("so that Postfix quickly skips unavailable hosts"); + msg_warn("you may need to increase the main.cf %s and %s", + VAR_MIN_BACKOFF_TIME, VAR_MAX_BACKOFF_TIME); + msg_warn("so that Postfix wastes less time on undeliverable mail"); + msg_warn("you may need to increase the master.cf %s process limit", + transport->name); + } + msg_warn("please avoid flushing the whole queue when you have"); + msg_warn("lots of deferred mail, that is bad for performance"); + msg_warn("to turn off these warnings specify: %s = 0", + VAR_QMGR_CLOG_WARN_TIME); + queue->clog_time_to_warn = now + var_qmgr_clog_warn_time; + } + } + return (entry); +} -- cgit v1.2.3