1 files changed, 654 insertions, 0 deletions

diff --git a/src/plugins/lazy-expunge/lazy-expunge-plugin.c b/src/plugins/lazy-expunge/lazy-expunge-plugin.c
new file mode 100644
index 0000000..ca10839
--- /dev/null
+++ b/src/plugins/lazy-expunge/lazy-expunge-plugin.c
@@ -0,0 +1,654 @@
+/* Copyright (c) 2006-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "ioloop.h"
+#include "array.h"
+#include "str.h"
+#include "hash.h"
+#include "seq-range-array.h"
+#include "mkdir-parents.h"
+#include "mail-storage-private.h"
+#include "mail-search-build.h"
+#include "mailbox-list-private.h"
+#include "mailbox-match-plugin.h"
+#include "mail-namespace.h"
+#include "lazy-expunge-plugin.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <time.h>
+
+#define LAZY_EXPUNGE_CONTEXT(obj) \
+	MODULE_CONTEXT(obj, lazy_expunge_mail_storage_module)
+#define LAZY_EXPUNGE_CONTEXT_REQUIRE(obj) \
+	MODULE_CONTEXT_REQUIRE(obj, lazy_expunge_mail_storage_module)
+#define LAZY_EXPUNGE_LIST_CONTEXT(obj) \
+	MODULE_CONTEXT(obj, lazy_expunge_mailbox_list_module)
+#define LAZY_EXPUNGE_USER_CONTEXT(obj) \
+	MODULE_CONTEXT(obj, lazy_expunge_mail_user_module)
+#define LAZY_EXPUNGE_USER_CONTEXT_REQUIRE(obj) \
+	MODULE_CONTEXT_REQUIRE(obj, lazy_expunge_mail_user_module)
+#define LAZY_EXPUNGE_MAIL_CONTEXT(obj) \
+	MODULE_CONTEXT(obj, lazy_expunge_mail_module)
+#define LAZY_EXPUNGE_MAIL_CONTEXT_REQUIRE(obj) \
+	MODULE_CONTEXT_REQUIRE(obj, lazy_expunge_mail_module)
+
+struct lazy_expunge_mail {
+	union mail_module_context module_ctx;
+	bool moving;
+	bool recursing;
+};
+
+struct lazy_expunge_mail_user {
+	union mail_user_module_context module_ctx;
+
+	struct mail_namespace *lazy_ns;
+	struct mailbox_match_plugin *excludes;
+	const char *lazy_mailbox_vname;
+	const char *env;
+	bool copy_only_last_instance;
+};
+
+struct lazy_expunge_mailbox_list {
+	union mailbox_list_module_context module_ctx;
+
+	bool allow_rename:1;
+	bool internal_namespace:1;
+};
+
+struct lazy_expunge_transaction {
+	union mailbox_transaction_module_context module_ctx;
+
+	struct mailbox *dest_box;
+	struct mailbox_transaction_context *dest_trans;
+
+	pool_t pool;
+	HASH_TABLE(const char *, void *) guids;
+
+	char *delayed_errstr;
+	char *delayed_internal_errstr;
+	enum mail_error delayed_error;
+
+	bool copy_only_last_instance;
+};
+
+const char *lazy_expunge_plugin_version = DOVECOT_ABI_VERSION;
+
+static MODULE_CONTEXT_DEFINE_INIT(lazy_expunge_mail_storage_module,
+				  &mail_storage_module_register);
+static MODULE_CONTEXT_DEFINE_INIT(lazy_expunge_mail_module,
+				  &mail_module_register);
+static MODULE_CONTEXT_DEFINE_INIT(lazy_expunge_mailbox_list_module,
+				  &mailbox_list_module_register);
+static MODULE_CONTEXT_DEFINE_INIT(lazy_expunge_mail_user_module,
+				  &mail_user_module_register);
+
+static const char *
+get_dest_vname(struct mailbox_list *list, struct mailbox *src_box)
+{
+	struct lazy_expunge_mail_user *luser =
+		LAZY_EXPUNGE_USER_CONTEXT_REQUIRE(list->ns->user);
+	const char *name;
+	char src_sep, dest_sep;
+
+	if (luser->lazy_mailbox_vname != NULL)
+		return luser->lazy_mailbox_vname;
+
+	/* use the (canonical / unaliased) storage name */
+	name = src_box->name;
+	/* replace hierarchy separators with destination virtual separator */
+	src_sep = mailbox_list_get_hierarchy_sep(src_box->list);
+	dest_sep = mail_namespace_get_sep(list->ns);
+	if (src_sep != dest_sep) {
+		string_t *str = t_str_new(128);
+		unsigned int i;
+
+		for (i = 0; name[i] != '\0'; i++) {
+			if (name[i] == src_sep)
+				str_append_c(str, dest_sep);
+			else
+				str_append_c(str, name[i]);
+		}
+		name = str_c(str);
+	}
+	/* add expunge namespace prefix. the name is now a proper vname */
+	return t_strconcat(list->ns->prefix, name, NULL);
+}
+
+static struct mailbox *
+mailbox_open_or_create(struct mailbox_list *list, struct mailbox *src_box,
+		       const char **error_r)
+{
+	struct mailbox *box;
+	enum mail_error error;
+	const char *name;
+
+	name = get_dest_vname(list, src_box);
+
+	box = mailbox_alloc(list, name, MAILBOX_FLAG_NO_INDEX_FILES |
+			    MAILBOX_FLAG_SAVEONLY | MAILBOX_FLAG_IGNORE_ACLS);
+	if (mailbox_open(box) == 0) {
+		*error_r = NULL;
+		return box;
+	}
+
+	*error_r = mailbox_get_last_internal_error(box, &error);
+	if (error != MAIL_ERROR_NOTFOUND) {
+		*error_r = t_strdup_printf("Failed to open mailbox %s: %s",
+					   name, *error_r);
+		mailbox_free(&box);
+		return NULL;
+	}
+
+	/* try creating and re-opening it. */
+	if (mailbox_create(box, NULL, FALSE) < 0 &&
+	    mailbox_get_last_mail_error(box) != MAIL_ERROR_EXISTS) {
+		*error_r = t_strdup_printf("Failed to create mailbox %s: %s", name,
+					   mailbox_get_last_internal_error(box, NULL));
+		mailbox_free(&box);
+		return NULL;
+	}
+	if (mailbox_open(box) < 0) {
+		*error_r = t_strdup_printf("Failed to open created mailbox %s: %s", name,
+					   mailbox_get_last_internal_error(box, NULL));
+		mailbox_free(&box);
+		return NULL;
+	}
+	return box;
+}
+
+static unsigned int
+lazy_expunge_count_in_transaction(struct lazy_expunge_transaction *lt,
+				  const char *guid)
+{
+	void *refcountp;
+	unsigned int refcount;
+
+	if (lt->pool == NULL) {
+		lt->pool = pool_alloconly_create("lazy expunge transaction",
+						 1024);
+		hash_table_create(&lt->guids, lt->pool, 0, str_hash, strcmp);
+	}
+
+	refcountp = hash_table_lookup(lt->guids, guid);
+	refcount = POINTER_CAST_TO(refcountp, unsigned int) + 1;
+	refcountp = POINTER_CAST(refcount);
+	if (refcount == 1) {
+		guid = p_strdup(lt->pool, guid);
+		hash_table_insert(lt->guids, guid, refcountp);
+	} else {
+		hash_table_update(lt->guids, guid, refcountp);
+	}
+	return refcount-1;
+}
+
+static int lazy_expunge_mail_is_last_instance(struct mail *_mail)
+{
+	struct mail_private *mail = (struct mail_private *)_mail;
+	struct lazy_expunge_transaction *lt =
+		LAZY_EXPUNGE_CONTEXT_REQUIRE(_mail->transaction);
+	const char *value, *errstr;
+	unsigned long refcount;
+	enum mail_error error;
+
+	/* mail is reused by the search query, so the next mail_prefetch() on
+	   it will try to prefetch the refcount */
+	mail->wanted_fields |= MAIL_FETCH_REFCOUNT;
+
+	if (mail_get_special(_mail, MAIL_FETCH_REFCOUNT, &value) < 0) {
+		errstr = mailbox_get_last_internal_error(_mail->box, &error);
+		if (error == MAIL_ERROR_EXPUNGED) {
+			/* already expunged - just ignore it */
+			return 0;
+		}
+		mail_set_critical(_mail,
+			"lazy_expunge: Couldn't lookup message's refcount: %s",
+			errstr);
+		return -1;
+	}
+	if (*value == '\0') {
+		/* refcounts not supported by backend. assume all mails are
+		   the last instance. */
+		return 1;
+	}
+	if (str_to_ulong(value, &refcount) < 0)
+		i_panic("Invalid mail refcount number: %s", value);
+	if (refcount > 1) {
+		/* this probably isn't the last instance of the mail, but
+		   it's possible that the same mail was copied to this mailbox
+		   multiple times and we're deleting more than one instance
+		   within this transaction. in those cases each expunge will
+		   see the same refcount, so we need to adjust the refcount
+		   by tracking the expunged message's refcount IDs. */
+		if (mail_get_special(_mail, MAIL_FETCH_REFCOUNT_ID, &value) < 0) {
+			errstr = mailbox_get_last_internal_error(_mail->box, &error);
+			if (error == MAIL_ERROR_EXPUNGED) {
+				/* already expunged - just ignore it */
+				return 0;
+			}
+			mail_set_critical(_mail,
+				"lazy_expunge: Couldn't lookup message's refcount ID: %s", errstr);
+			return -1;
+		}
+		if (*value == '\0') {
+			/* refcount IDs not supported by backend, but refcounts
+			   are? not with our current backends. */
+			mail_set_critical(_mail,
+				"lazy_expunge: Message unexpectedly has no refcount ID");
+			return -1;
+		}
+		refcount -= lazy_expunge_count_in_transaction(lt, value);
+	}
+	return refcount <= 1 ? 1 : 0;
+}
+
+static bool lazy_expunge_is_internal_mailbox(struct mailbox *box)
+{
+	struct mail_namespace *ns = box->list->ns;
+	struct lazy_expunge_mail_user *luser =
+		LAZY_EXPUNGE_USER_CONTEXT(ns->user);
+	struct lazy_expunge_mailbox_list *llist =
+		LAZY_EXPUNGE_LIST_CONTEXT(box->list);
+
+	if (luser == NULL || llist == NULL) {
+		/* lazy_expunge not enabled at all */
+		return FALSE;
+	}
+	if (llist->internal_namespace) {
+		/* lazy-expunge namespace */
+		return TRUE;
+	}
+	if (luser->lazy_mailbox_vname != NULL &&
+	    strcmp(luser->lazy_mailbox_vname, box->vname) == 0) {
+		/* lazy-expunge mailbox */
+		return TRUE;
+	}
+	if (mailbox_match_plugin_exclude(luser->excludes, box)) {
+		/* Mailbox explicitly excluded by configuration */
+		return TRUE;
+	}
+	return FALSE;
+}
+
+static void lazy_expunge_set_error(struct lazy_expunge_transaction *lt,
+				   struct mail_storage *storage)
+{
+	const char *errstr;
+	enum mail_error error;
+
+	errstr = mail_storage_get_last_error(storage, &error);
+	if (error == MAIL_ERROR_EXPUNGED) {
+		/* expunging failed because the mail was already expunged.
+		   we don't want to fail because of that. */
+		return;
+	}
+
+	if (lt->delayed_error != MAIL_ERROR_NONE)
+		return;
+	lt->delayed_error = error;
+	lt->delayed_errstr = i_strdup(errstr);
+	lt->delayed_internal_errstr =
+		i_strdup(mail_storage_get_last_internal_error(storage, NULL));
+}
+
+static void lazy_expunge_mail_expunge_move(struct mail *_mail)
+{
+	struct mail_namespace *ns = _mail->box->list->ns;
+	struct lazy_expunge_mail_user *luser =
+		LAZY_EXPUNGE_USER_CONTEXT_REQUIRE(ns->user);
+	struct mail_private *mail = (struct mail_private *)_mail;
+	struct lazy_expunge_mail *mmail =
+		LAZY_EXPUNGE_MAIL_CONTEXT_REQUIRE(mail);
+	struct lazy_expunge_transaction *lt =
+		LAZY_EXPUNGE_CONTEXT_REQUIRE(_mail->transaction);
+	struct mail_save_context *save_ctx;
+	const char *error;
+
+	if (lt->dest_box == NULL) {
+		lt->dest_box = mailbox_open_or_create(luser->lazy_ns->list,
+						      _mail->box, &error);
+		if (lt->dest_box == NULL) {
+			mail_set_critical(_mail,
+				"lazy_expunge: Couldn't open expunge mailbox: "
+				"%s", error);
+			lazy_expunge_set_error(lt, _mail->box->storage);
+			return;
+		}
+		if (mailbox_sync(lt->dest_box, 0) < 0) {
+			mail_set_critical(_mail,
+				"lazy_expunge: Couldn't sync expunge mailbox");
+			lazy_expunge_set_error(lt, lt->dest_box->storage);
+			mailbox_free(&lt->dest_box);
+			return;
+		}
+
+		lt->dest_trans = mailbox_transaction_begin(lt->dest_box,
+					  MAILBOX_TRANSACTION_FLAG_EXTERNAL,
+					  __func__);
+	}
+
+	save_ctx = mailbox_save_alloc(lt->dest_trans);
+	mailbox_save_copy_flags(save_ctx, _mail);
+	save_ctx->data.flags &= ENUM_NEGATE(MAIL_DELETED);
+
+	mmail->recursing = TRUE;
+	if (mailbox_move(&save_ctx, _mail) < 0 && !_mail->expunged)
+		lazy_expunge_set_error(lt, lt->dest_box->storage);
+	mmail->recursing = FALSE;
+}
+
+static void lazy_expunge_mail_expunge(struct mail *_mail)
+{
+	struct lazy_expunge_transaction *lt =
+		LAZY_EXPUNGE_CONTEXT_REQUIRE(_mail->transaction);
+	struct mail_private *mail = (struct mail_private *)_mail;
+	struct lazy_expunge_mail *mmail =
+		LAZY_EXPUNGE_MAIL_CONTEXT_REQUIRE(mail);
+	struct mail *real_mail;
+	bool moving = mmail->moving;
+	int ret;
+
+	if (lt->delayed_error != MAIL_ERROR_NONE)
+		return;
+	if (mmail->recursing) {
+		mmail->module_ctx.super.expunge(_mail);
+		return;
+	}
+
+	/* Clear this in case the mail is used for non-move later on. */
+	mmail->moving = FALSE;
+
+	/* don't copy the mail if we're expunging from lazy_expunge
+	   namespace (even if it's via a virtual mailbox) */
+	if (mail_get_backend_mail(_mail, &real_mail) < 0) {
+		lazy_expunge_set_error(lt, _mail->box->storage);
+		return;
+	}
+	if (lazy_expunge_is_internal_mailbox(real_mail->box)) {
+		mmail->module_ctx.super.expunge(_mail);
+		return;
+	}
+
+	struct event_reason *reason =
+		event_reason_begin("lazy_expunge:expunge");
+	if (!lt->copy_only_last_instance)
+		ret = 1;
+	else {
+		/* we want to copy only the last instance of the mail to
+		   lazy_expunge namespace. other instances will be expunged
+		   immediately. */
+		if (moving)
+			ret = 0;
+		else {
+			ret = lazy_expunge_mail_is_last_instance(_mail);
+			if (ret < 0)
+				lazy_expunge_set_error(lt, _mail->box->storage);
+		}
+	}
+	if (ret > 0)
+		lazy_expunge_mail_expunge_move(_mail);
+	event_reason_end(&reason);
+
+	if (ret == 0) {
+		/* Not the last instance of the mail - expunge it normally.
+		   Since this is a normal expunge, do it without the
+		   reason_code. */
+		mmail->module_ctx.super.expunge(_mail);
+	}
+}
+
+static int lazy_expunge_copy(struct mail_save_context *ctx, struct mail *_mail)
+{
+	struct mail_private *mail = (struct mail_private *)_mail;
+	union mailbox_module_context *mbox =
+		LAZY_EXPUNGE_CONTEXT_REQUIRE(ctx->transaction->box);
+	struct lazy_expunge_mail *mmail = LAZY_EXPUNGE_MAIL_CONTEXT(mail);
+
+	if (mmail != NULL)
+		mmail->moving = ctx->moving;
+	return mbox->super.copy(ctx, _mail);
+}
+
+static struct mailbox_transaction_context *
+lazy_expunge_transaction_begin(struct mailbox *box,
+			       enum mailbox_transaction_flags flags,
+			       const char *reason)
+{
+	struct lazy_expunge_mail_user *luser =
+		LAZY_EXPUNGE_USER_CONTEXT_REQUIRE(box->list->ns->user);
+	union mailbox_module_context *mbox = LAZY_EXPUNGE_CONTEXT_REQUIRE(box);
+	struct mailbox_transaction_context *t;
+	struct lazy_expunge_transaction *lt;
+
+	t = mbox->super.transaction_begin(box, flags, reason);
+	lt = i_new(struct lazy_expunge_transaction, 1);
+	lt->copy_only_last_instance = luser->copy_only_last_instance;
+
+	MODULE_CONTEXT_SET(t, lazy_expunge_mail_storage_module, lt);
+	return t;
+}
+
+static void lazy_expunge_transaction_free(struct lazy_expunge_transaction *lt)
+{
+	if (lt->dest_trans != NULL)
+		mailbox_transaction_rollback(&lt->dest_trans);
+	if (lt->dest_box != NULL)
+		mailbox_free(&lt->dest_box);
+	hash_table_destroy(&lt->guids);
+	pool_unref(&lt->pool);
+	i_free(lt->delayed_errstr);
+	i_free(lt->delayed_internal_errstr);
+	i_free(lt);
+}
+
+static int
+lazy_expunge_transaction_commit(struct mailbox_transaction_context *ctx,
+				struct mail_transaction_commit_changes *changes_r)
+{
+	union mailbox_module_context *mbox = LAZY_EXPUNGE_CONTEXT_REQUIRE(ctx->box);
+	struct lazy_expunge_transaction *lt = LAZY_EXPUNGE_CONTEXT_REQUIRE(ctx);
+	int ret;
+
+	if (lt->dest_trans != NULL && lt->delayed_error == MAIL_ERROR_NONE) {
+		if (mailbox_transaction_commit(&lt->dest_trans) < 0) {
+			lazy_expunge_set_error(lt, ctx->box->storage);
+		}
+	}
+
+	if (lt->delayed_error == MAIL_ERROR_NONE)
+		ret = mbox->super.transaction_commit(ctx, changes_r);
+	else if (lt->delayed_error != MAIL_ERROR_TEMP) {
+		mail_storage_set_error(ctx->box->storage, lt->delayed_error,
+				       lt->delayed_errstr);
+		mbox->super.transaction_rollback(ctx);
+		ret = -1;
+	} else {
+		mailbox_set_critical(ctx->box,
+			"Lazy-expunge transaction failed: %s",
+			lt->delayed_internal_errstr);
+		mbox->super.transaction_rollback(ctx);
+		ret = -1;
+	}
+	lazy_expunge_transaction_free(lt);
+	return ret;
+}
+
+static void
+lazy_expunge_transaction_rollback(struct mailbox_transaction_context *ctx)
+{
+	union mailbox_module_context *mbox = LAZY_EXPUNGE_CONTEXT_REQUIRE(ctx->box);
+	struct lazy_expunge_transaction *lt = LAZY_EXPUNGE_CONTEXT_REQUIRE(ctx);
+
+	mbox->super.transaction_rollback(ctx);
+	lazy_expunge_transaction_free(lt);
+}
+
+static void lazy_expunge_mail_allocated(struct mail *_mail)
+{
+	struct lazy_expunge_transaction *lt =
+		LAZY_EXPUNGE_CONTEXT(_mail->transaction);
+	struct mail_private *mail = (struct mail_private *)_mail;
+	struct mail_vfuncs *v = mail->vlast;
+	struct lazy_expunge_mail *mmail;
+
+	if (lt == NULL)
+		return;
+
+	mmail = p_new(mail->pool, struct lazy_expunge_mail, 1);
+	mmail->module_ctx.super = *v;
+	mail->vlast = &mmail->module_ctx.super;
+
+	v->expunge = lazy_expunge_mail_expunge;
+	MODULE_CONTEXT_SET(mail, lazy_expunge_mail_module, mmail);
+}
+
+static int
+lazy_expunge_mailbox_rename(struct mailbox *src, struct mailbox *dest)
+{
+	union mailbox_module_context *lbox = LAZY_EXPUNGE_CONTEXT_REQUIRE(src);
+	struct lazy_expunge_mailbox_list *src_llist =
+		LAZY_EXPUNGE_LIST_CONTEXT(src->list);
+	struct lazy_expunge_mailbox_list *dest_llist =
+		LAZY_EXPUNGE_LIST_CONTEXT(dest->list);
+
+	i_assert(src_llist != NULL && dest_llist != NULL);
+
+	if (!src_llist->allow_rename &&
+	    (src_llist->internal_namespace ||
+	     dest_llist->internal_namespace)) {
+		mail_storage_set_error(src->storage, MAIL_ERROR_NOTPOSSIBLE,
+			"Can't rename mailboxes to/from expunge namespace.");
+		return -1;
+	}
+	return lbox->super.rename_box(src, dest);
+}
+
+static void lazy_expunge_mailbox_allocated(struct mailbox *box)
+{
+	struct lazy_expunge_mailbox_list *llist =
+		LAZY_EXPUNGE_LIST_CONTEXT(box->list);
+	union mailbox_module_context *mbox;
+	struct mailbox_vfuncs *v = box->vlast;
+
+	if (llist == NULL || (box->flags & MAILBOX_FLAG_DELETE_UNSAFE) != 0)
+		return;
+
+	mbox = p_new(box->pool, union mailbox_module_context, 1);
+	mbox->super = *v;
+	box->vlast = &mbox->super;
+	MODULE_CONTEXT_SET_SELF(box, lazy_expunge_mail_storage_module, mbox);
+
+	if (!lazy_expunge_is_internal_mailbox(box)) {
+		v->copy = lazy_expunge_copy;
+		v->transaction_begin = lazy_expunge_transaction_begin;
+		v->transaction_commit = lazy_expunge_transaction_commit;
+		v->transaction_rollback = lazy_expunge_transaction_rollback;
+		v->rename_box = lazy_expunge_mailbox_rename;
+	} else if (llist->internal_namespace) {
+		v->rename_box = lazy_expunge_mailbox_rename;
+	} else {
+		/* internal mailbox in a non-internal namespace -
+		   don't add any unnecessary restrictions to it. if it's not
+		   wanted, just use the ACL plugin. */
+	}
+}
+
+static void lazy_expunge_mailbox_list_created(struct mailbox_list *list)
+{
+	struct lazy_expunge_mail_user *luser =
+		LAZY_EXPUNGE_USER_CONTEXT(list->ns->user);
+	struct lazy_expunge_mailbox_list *llist;
+
+	if (luser == NULL)
+		return;
+
+	/* if this is one of our internal namespaces, mark it as such before
+	   quota plugin sees it */
+	if (strcmp(list->ns->prefix, luser->env) == 0)
+		list->ns->flags |= NAMESPACE_FLAG_NOQUOTA;
+
+	if (list->ns->type == MAIL_NAMESPACE_TYPE_PRIVATE) {
+		llist = p_new(list->pool, struct lazy_expunge_mailbox_list, 1);
+		MODULE_CONTEXT_SET(list, lazy_expunge_mailbox_list_module,
+				   llist);
+	}
+}
+
+static void
+lazy_expunge_mail_namespaces_created(struct mail_namespace *namespaces)
+{
+	struct lazy_expunge_mail_user *luser =
+		LAZY_EXPUNGE_USER_CONTEXT(namespaces->user);
+	struct lazy_expunge_mailbox_list *llist;
+
+	if (luser == NULL)
+		return;
+
+	luser->lazy_ns = mail_namespace_find_prefix(namespaces, luser->env);
+	if (luser->lazy_ns != NULL) {
+		/* we don't want to override this namespace's expunge operation. */
+		llist = LAZY_EXPUNGE_LIST_CONTEXT(luser->lazy_ns->list);
+		i_assert(llist != NULL);
+		llist->internal_namespace = TRUE;
+	} else {
+		/* store the the expunged mails to the specified mailbox. */
+		luser->lazy_ns = mail_namespace_find(namespaces, luser->env);
+		luser->lazy_mailbox_vname = luser->env;
+	}
+	mail_namespace_ref(luser->lazy_ns);
+}
+
+static void lazy_expunge_user_deinit(struct mail_user *user)
+{
+	struct lazy_expunge_mail_user *luser = LAZY_EXPUNGE_USER_CONTEXT_REQUIRE(user);
+
+	/* mail_namespaces_created hook isn't necessarily ever called */
+	if (luser->lazy_ns != NULL)
+		mail_namespace_unref(&luser->lazy_ns);
+	mailbox_match_plugin_deinit(&luser->excludes);
+
+	luser->module_ctx.super.deinit(user);
+}
+
+static void lazy_expunge_mail_user_created(struct mail_user *user)
+{
+	struct mail_user_vfuncs *v = user->vlast;
+	struct lazy_expunge_mail_user *luser;
+	const char *env;
+
+	env = mail_user_plugin_getenv(user, "lazy_expunge");
+	if (env != NULL && env[0] != '\0') {
+		luser = p_new(user->pool, struct lazy_expunge_mail_user, 1);
+		luser->module_ctx.super = *v;
+		user->vlast = &luser->module_ctx.super;
+		v->deinit = lazy_expunge_user_deinit;
+		luser->env = env;
+		luser->copy_only_last_instance =
+			mail_user_plugin_getenv_bool(user, "lazy_expunge_only_last_instance");
+		luser->excludes = mailbox_match_plugin_init(user, "lazy_expunge_exclude");
+
+		MODULE_CONTEXT_SET(user, lazy_expunge_mail_user_module, luser);
+	} else {
+		e_debug(user->event, "lazy_expunge: No lazy_expunge setting - "
+			"plugin disabled");
+	}
+}
+
+static struct mail_storage_hooks lazy_expunge_mail_storage_hooks = {
+	.mail_user_created = lazy_expunge_mail_user_created,
+	.mail_namespaces_created = lazy_expunge_mail_namespaces_created,
+	.mailbox_list_created = lazy_expunge_mailbox_list_created,
+	.mailbox_allocated = lazy_expunge_mailbox_allocated,
+	.mail_allocated = lazy_expunge_mail_allocated
+};
+
+void lazy_expunge_plugin_init(struct module *module)
+{
+	mail_storage_hooks_add(module, &lazy_expunge_mail_storage_hooks);
+}
+
+void lazy_expunge_plugin_deinit(void)
+{
+	mail_storage_hooks_remove(&lazy_expunge_mail_storage_hooks);
+}