src/lib-storage/mail-storage.c

	mail-storage.c revision 5f352310311252d2da139beb208c21fcb8fdae89
02c335c23bf5fa225a467c19f2c063fb0dc7b8c3Timo Sirainen/* Copyright (c) 2002-2015 Dovecot authors, see the included COPYING file */
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "lib.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "ioloop.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "array.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "llist.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "str.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "str-sanitize.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "unichar.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "istream.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "eacces-error.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mkdir-parents.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "time-util.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "var-expand.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "dsasl-client.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "imap-date.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "settings-parser.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-index-private.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-index-alloc-cache.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mailbox-tree.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mailbox-list-private.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-storage-private.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-storage-settings.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-namespace.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-search.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mail-search-register.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mailbox-search-result-private.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include "mailbox-guid-cache.h"
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#include <ctype.h>
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz#define MAILBOX_DELETE_RETRY_SECS 30
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzextern struct mail_search_register *mail_search_register_imap;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzextern struct mail_search_register *mail_search_register_human;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzstruct mail_storage_module_register mail_storage_module_register = { 0 };
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzstruct mail_module_register mail_module_register = { 0 };
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzstruct mail_storage_mail_index_module mail_storage_mail_index_module =
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    MODULE_CONTEXT_INIT(&mail_index_module_register);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M SlusarzARRAY_TYPE(mail_storage) mail_storage_classes;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzvoid mail_storage_init(void)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    dsasl_clients_init();
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    mailbox_attributes_init();
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    mailbox_lists_init();
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    mail_storage_hooks_init();
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    i_array_init(&mail_storage_classes, 8);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzvoid mail_storage_deinit(void)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    if (mail_search_register_human != NULL)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        mail_search_register_deinit(&mail_search_register_human);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    if (mail_search_register_imap != NULL)
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen        mail_search_register_deinit(&mail_search_register_imap);
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    if (array_is_created(&mail_storage_classes))
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen        array_free(&mail_storage_classes);
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    mail_storage_hooks_deinit();
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    mailbox_lists_deinit();
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    mailbox_attributes_deinit();
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    dsasl_clients_deinit();
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzvoid mail_storage_class_register(struct mail_storage *storage_class)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    i_assert(mail_storage_find_class(storage_class->name) == NULL);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    /* append it after the list, so the autodetection order is correct */
2d7ad82a356217c7d763c7075aa3526129373bd8Timo Sirainen    array_append(&mail_storage_classes, &storage_class, 1);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzvoid mail_storage_class_unregister(struct mail_storage *storage_class)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    struct mail_storage *const *classes;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    unsigned int i, count;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    classes = array_get(&mail_storage_classes, &count);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    for (i = 0; i < count; i++) {
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        if (classes[i] == storage_class) {
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz            array_delete(&mail_storage_classes, i, 1);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz            break;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        }
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    }
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzstruct mail_storage *mail_storage_find_class(const char *name)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    struct mail_storage *const *classes;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    unsigned int i, count;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    i_assert(name != NULL);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    classes = array_get(&mail_storage_classes, &count);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    for (i = 0; i < count; i++) {
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        if (strcasecmp(classes[i]->name, name) == 0)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz            return classes[i];
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    }
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    return NULL;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzstatic struct mail_storage *
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzmail_storage_autodetect(const struct mail_namespace *ns,
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz            struct mailbox_list_settings *set)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    struct mail_storage *const *classes;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    unsigned int i, count;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    classes = array_get(&mail_storage_classes, &count);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    for (i = 0; i < count; i++) {
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        if (classes[i]->v.autodetect != NULL) {
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz            if (classes[i]->v.autodetect(ns, set))
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz                return classes[i];
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        }
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    }
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    return NULL;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzstatic void
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarzmail_storage_set_autodetection(const char **data, const char **driver)
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz{
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    const char *p;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    /* check if data is in driver:data format (eg. mbox:~/mail) */
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    p = *data;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    while (i_isalnum(*p) || *p == '_') p++;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    if (*p == ':' && p != *data) {
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        /* no autodetection if the storage driver is given. */
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        *driver = t_strdup_until(*data, p);
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz        *data = p + 1;
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz    }
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz}
51ed197520dd9ea534fbc3bc1790ebe3cb5421e2Michael M Slusarz
static struct mail_storage *
mail_storage_get_class(struct mail_namespace *ns, const char *driver,
               struct mailbox_list_settings *list_set,
               enum mail_storage_flags flags, const char **error_r)
{
    struct mail_storage *storage_class = NULL;
    const char *home;

    if (driver == NULL) {
        /* no mail_location, autodetect */
    } else if (strcmp(driver, "auto") == 0) {
        /* explicit autodetection with "auto" driver. */
        if (list_set->root_dir != NULL &&
            *list_set->root_dir == '\0') {
            /* handle the same as with driver=NULL */
            list_set->root_dir = NULL;
        }
    } else {
        storage_class = mail_user_get_storage_class(ns->user, driver);
        if (storage_class == NULL) {
            *error_r = t_strdup_printf(
                "Unknown mail storage driver %s", driver);
            return NULL;
        }
    }

    if (list_set->root_dir == NULL || *list_set->root_dir == '\0') {
        /* no root directory given. is this allowed? */
        const struct mailbox_list *list;

        list = list_set->layout == NULL ? NULL :
            mailbox_list_find_class(list_set->layout);
        if (storage_class == NULL &&
            (flags & MAIL_STORAGE_FLAG_NO_AUTODETECTION) == 0) {
            /* autodetection should take care of this */
        } else if (storage_class != NULL &&
               (storage_class->class_flags & MAIL_STORAGE_CLASS_FLAG_NO_ROOT) != 0) {
            /* root not required for this storage */
        } else if (list != NULL &&
               (list->props & MAILBOX_LIST_PROP_NO_ROOT) != 0) {
            /* root not required for this layout */
        } else {
            *error_r = "Root mail directory not given";
            return NULL;
        }
    }

    if (storage_class != NULL) {
        storage_class->v.get_list_settings(ns, list_set);
        return storage_class;
    }

    storage_class = mail_storage_autodetect(ns, list_set);
    if (storage_class != NULL)
        return storage_class;

    (void)mail_user_get_home(ns->user, &home);
    if (home == NULL || *home == '\0') home = "(not set)";

    if (ns->set->location == NULL || *ns->set->location == '\0') {
        *error_r = t_strdup_printf(
            "Mail storage autodetection failed with home=%s", home);
    } else if (strncmp(ns->set->location, "auto:", 5) == 0) {
        *error_r = t_strdup_printf(
            "Autodetection failed for %s (home=%s)",
            ns->set->location, home);
    } else {
        *error_r = t_strdup_printf(
            "Ambiguous mail location setting, "
            "don't know what to do with it: %s "
            "(try prefixing it with mbox: or maildir:)",
            ns->set->location);
    }
    return NULL;
}

static int
mail_storage_verify_root(const char *root_dir, bool autocreate,
             const char **error_r)
{
    struct stat st;

    if (stat(root_dir, &st) == 0) {
        /* exists */
        return 1;
    } else if (errno == EACCES) {
        *error_r = mail_error_eacces_msg("stat", root_dir);
        return -1;
    } else if (errno != ENOENT && errno != ENOTDIR) {
        *error_r = t_strdup_printf("stat(%s) failed: %m", root_dir);
        return -1;
    } else if (!autocreate) {
        *error_r = t_strdup_printf(
            "Root mail directory doesn't exist: %s", root_dir);
        return -1;
    } else {
        /* doesn't exist */
        return 0;
    }
}

static int
mail_storage_create_root(struct mailbox_list *list,
             enum mail_storage_flags flags, const char **error_r)
{
    const char *root_dir, *error;
    bool autocreate;
    int ret;

    if (!mailbox_list_get_root_path(list, MAILBOX_LIST_PATH_TYPE_MAILBOX,
                    &root_dir)) {
        /* storage doesn't use directories (e.g. shared root) */
        return 0;
    }

    if ((flags & MAIL_STORAGE_FLAG_NO_AUTOVERIFY) != 0) {
        if (!list->mail_set->mail_debug)
            return 0;

        /* we don't need to verify, but since debugging is
           enabled, check and log if the root doesn't exist */
        if (mail_storage_verify_root(root_dir, FALSE, &error) < 0) {
            i_debug("Namespace %s: Creating storage despite: %s",
                list->ns->prefix, error);
        }
        return 0;
    }

    autocreate = (flags & MAIL_STORAGE_FLAG_NO_AUTOCREATE) == 0;
    ret = mail_storage_verify_root(root_dir, autocreate, error_r);
    if (ret == 0) {
        ret = mailbox_list_try_mkdir_root(list, root_dir,
                          MAILBOX_LIST_PATH_TYPE_MAILBOX,
                          error_r);
    }
    return ret < 0 ? -1 : 0;
}

static bool
mail_storage_match_class(struct mail_storage *storage,
             const struct mail_storage *storage_class,
             const struct mailbox_list_settings *set)
{
    if (strcmp(storage->name, storage_class->name) != 0)
        return FALSE;

    if ((storage->class_flags & MAIL_STORAGE_CLASS_FLAG_UNIQUE_ROOT) != 0 &&
        strcmp(storage->unique_root_dir, set->root_dir) != 0)
        return FALSE;

    if (strcmp(storage->name, "shared") == 0) {
        /* allow multiple independent shared namespaces */
        return FALSE;
    }
    return TRUE;
}

static struct mail_storage *
mail_storage_find(struct mail_user *user,
          const struct mail_storage *storage_class,
          const struct mailbox_list_settings *set)
{
    struct mail_storage *storage = user->storages;

    for (; storage != NULL; storage = storage->next) {
        if (mail_storage_match_class(storage, storage_class, set))
            return storage;
    }
    return NULL;
}

int mail_storage_create_full(struct mail_namespace *ns, const char *driver,
                 const char *data, enum mail_storage_flags flags,
                 struct mail_storage **storage_r,
                 const char **error_r)
{
    struct mail_storage *storage_class, *storage = NULL;
    struct mailbox_list *list;
    struct mailbox_list_settings list_set;
    enum mailbox_list_flags list_flags = 0;
    const char *p;

    if ((flags & MAIL_STORAGE_FLAG_KEEP_HEADER_MD5) == 0 &&
        ns->mail_set->pop3_uidl_format != NULL) {
        /* if pop3_uidl_format contains %m, we want to keep the
           header MD5 sums stored even if we're not running POP3
           right now. */
        p = ns->mail_set->pop3_uidl_format;
        while ((p = strchr(p, '%')) != NULL) {
            if (p[1] == '%')
                p += 2;
            else if (var_get_key(++p) == 'm') {
                flags |= MAIL_STORAGE_FLAG_KEEP_HEADER_MD5;
                break;
            }
        }
    }

    memset(&list_set, 0, sizeof(list_set));
    list_set.mailbox_dir_name = "";
    list_set.maildir_name = "";
    if (data == NULL) {
        /* autodetect */
    } else if (driver != NULL && strcmp(driver, "shared") == 0) {
        /* internal shared namespace */
        list_set.root_dir = ns->user->set->base_dir;
    } else {
        if (driver == NULL)
            mail_storage_set_autodetection(&data, &driver);
        if (mailbox_list_settings_parse(ns->user, data, &list_set,
                        error_r) < 0)
            return -1;
    }

    storage_class = mail_storage_get_class(ns, driver, &list_set, flags,
                           error_r);
    if (storage_class == NULL)
        return -1;
    i_assert(list_set.layout != NULL);

    if (ns->list == NULL) {
        /* first storage for namespace */
        if (mail_storage_is_mailbox_file(storage_class))
            list_flags |= MAILBOX_LIST_FLAG_MAILBOX_FILES;
        if ((storage_class->class_flags & MAIL_STORAGE_CLASS_FLAG_NO_ROOT) != 0)
            list_flags |= MAILBOX_LIST_FLAG_NO_MAIL_FILES;
        if (mailbox_list_create(list_set.layout, ns, &list_set,
                    list_flags, &list, error_r) < 0) {
            *error_r = t_strdup_printf("Mailbox list driver %s: %s",
                           list_set.layout, *error_r);
            return -1;
        }
        if ((storage_class->class_flags & MAIL_STORAGE_CLASS_FLAG_NO_ROOT) == 0) {
            if (mail_storage_create_root(ns->list, flags, error_r) < 0)
                return -1;
        }
    }

    storage = mail_storage_find(ns->user, storage_class, &list_set);
    if (storage != NULL) {
        /* using an existing storage */
        storage->refcount++;
        mail_namespace_add_storage(ns, storage);
        *storage_r = storage;
        return 0;
    }

    storage = storage_class->v.alloc();
    storage->refcount = 1;
    storage->storage_class = storage_class;
    storage->user = ns->user;
    storage->set = ns->mail_set;
    storage->flags = flags;
    p_array_init(&storage->module_contexts, storage->pool, 5);

    if (storage->v.create != NULL &&
        storage->v.create(storage, ns, error_r) < 0) {
        *error_r = t_strdup_printf("%s: %s", storage->name, *error_r);
        pool_unref(&storage->pool);
        return -1;
    }

    T_BEGIN {
        hook_mail_storage_created(storage);
    } T_END;

    DLLIST_PREPEND(&ns->user->storages, storage);
    mail_namespace_add_storage(ns, storage);
    *storage_r = storage;
    return 0;
}

int mail_storage_create(struct mail_namespace *ns, const char *driver,
            enum mail_storage_flags flags, const char **error_r)
{
    struct mail_storage *storage;

    return mail_storage_create_full(ns, driver, ns->set->location,
                    flags, &storage, error_r);
}

void mail_storage_unref(struct mail_storage **_storage)
{
    struct mail_storage *storage = *_storage;

    i_assert(storage->refcount > 0);

    /* set *_storage=NULL only after calling destroy() callback.
       for example mdbox wants to access ns->storage */
    if (--storage->refcount > 0) {
        *_storage = NULL;
        return;
    }

    if (storage->mailboxes != NULL) {
        i_panic("Trying to deinit storage without freeing mailbox %s",
            storage->mailboxes->vname);
    }
    if (storage->obj_refcount != 0)
        i_panic("Trying to deinit storage before freeing its objects");

    DLLIST_REMOVE(&storage->user->storages, storage);

    storage->v.destroy(storage);
    i_free(storage->error_string);
    if (array_is_created(&storage->error_stack)) {
        i_assert(array_count(&storage->error_stack) == 0);
        array_free(&storage->error_stack);
    }

    *_storage = NULL;
    pool_unref(&storage->pool);

    mail_index_alloc_cache_destroy_unrefed();
}

void mail_storage_obj_ref(struct mail_storage *storage)
{
    i_assert(storage->refcount > 0);

    if (storage->obj_refcount++ == 0)
        mail_user_ref(storage->user);
}

void mail_storage_obj_unref(struct mail_storage *storage)
{
    i_assert(storage->refcount > 0);
    i_assert(storage->obj_refcount > 0);

    if (--storage->obj_refcount == 0) {
        struct mail_user *user = storage->user;
        mail_user_unref(&user);
    }
}

void mail_storage_clear_error(struct mail_storage *storage)
{
    i_free_and_null(storage->error_string);

    storage->error = MAIL_ERROR_NONE;
}

void mail_storage_set_error(struct mail_storage *storage,
                enum mail_error error, const char *string)
{
    i_free(storage->error_string);
    storage->error_string = i_strdup(string);
    storage->error = error;
}

void mail_storage_set_internal_error(struct mail_storage *storage)
{
    const char *str;

    str = t_strflocaltime(MAIL_ERRSTR_CRITICAL_MSG_STAMP, ioloop_time);

    i_free(storage->error_string);
    storage->error_string = i_strdup(str);
    storage->error = MAIL_ERROR_TEMP;
}

void mail_storage_set_critical(struct mail_storage *storage,
                   const char *fmt, ...)
{
    va_list va;

    va_start(va, fmt);
    i_error("%s", t_strdup_vprintf(fmt, va));
    va_end(va);

    /* critical errors may contain sensitive data, so let user
       see only "Internal error" with a timestamp to make it
       easier to look from log files the actual error message. */
    mail_storage_set_internal_error(storage);
}

void mail_storage_copy_error(struct mail_storage *dest,
                 struct mail_storage *src)
{
    const char *str;
    enum mail_error error;

    if (src == dest)
        return;

    str = mail_storage_get_last_error(src, &error);
    mail_storage_set_error(dest, error, str);
}

void mail_storage_copy_list_error(struct mail_storage *storage,
                  struct mailbox_list *list)
{
    const char *str;
    enum mail_error error;

    str = mailbox_list_get_last_error(list, &error);
    mail_storage_set_error(storage, error, str);
}

void mailbox_set_index_error(struct mailbox *box)
{
    if (mail_index_is_deleted(box->index))
        mailbox_set_deleted(box);
    else
        mail_storage_set_internal_error(box->storage);
    mail_index_reset_error(box->index);
}

const struct mail_storage_settings *
mail_storage_get_settings(struct mail_storage *storage)
{
    return storage->set;
}

struct mail_user *mail_storage_get_user(struct mail_storage *storage)
{
    return storage->user;
}

void mail_storage_set_callbacks(struct mail_storage *storage,
                struct mail_storage_callbacks *callbacks,
                void *context)
{
    storage->callbacks = *callbacks;
    storage->callback_context = context;
}

int mail_storage_purge(struct mail_storage *storage)
{
    return storage->v.purge == NULL ? 0 :
        storage->v.purge(storage);
}

const char *mail_storage_get_last_error(struct mail_storage *storage,
                    enum mail_error *error_r)
{
    /* We get here only in error situations, so we have to return some
       error. If storage->error is NONE, it means we forgot to set it at
       some point.. */
    if (storage->error == MAIL_ERROR_NONE) {
        if (error_r != NULL)
            *error_r = MAIL_ERROR_TEMP;
        return storage->error_string != NULL ? storage->error_string :
            "BUG: Unknown internal error";
    }

    if (storage->error_string == NULL) {
        /* This shouldn't happen.. */
        storage->error_string =
            i_strdup_printf("BUG: Unknown 0x%x error",
                    storage->error);
    }

    if (error_r != NULL)
        *error_r = storage->error;
    return storage->error_string;
}

const char *mailbox_get_last_error(struct mailbox *box,
                   enum mail_error *error_r)
{
    return mail_storage_get_last_error(box->storage, error_r);
}

enum mail_error mailbox_get_last_mail_error(struct mailbox *box)
{
    enum mail_error error;

    mail_storage_get_last_error(box->storage, &error);
    return error;
}

void mail_storage_last_error_push(struct mail_storage *storage)
{
    struct mail_storage_error *err;

    if (!array_is_created(&storage->error_stack))
        i_array_init(&storage->error_stack, 2);
    err = array_append_space(&storage->error_stack);
    err->error_string = i_strdup(storage->error_string);
    err->error = storage->error;
}

void mail_storage_last_error_pop(struct mail_storage *storage)
{
    unsigned int count = array_count(&storage->error_stack);
    const struct mail_storage_error *err =
        array_idx(&storage->error_stack, count-1);

    i_free(storage->error_string);
    storage->error_string = err->error_string;
    storage->error = err->error;
    array_delete(&storage->error_stack, count-1, 1);
}

bool mail_storage_is_mailbox_file(struct mail_storage *storage)
{
    return (storage->class_flags &
        MAIL_STORAGE_CLASS_FLAG_MAILBOX_IS_FILE) != 0;
}

bool mail_storage_set_error_from_errno(struct mail_storage *storage)
{
    const char *error_string;
    enum mail_error error;

    if (!mail_error_from_errno(&error, &error_string))
        return FALSE;
    if (storage->set->mail_debug && error != MAIL_ERROR_NOTFOUND) {
        /* debugging is enabled - admin may be debugging a
           (permission) problem, so return FALSE to get the caller to
           log the full error message. */
        return FALSE;
    }

    mail_storage_set_error(storage, error, error_string);
    return TRUE;
}

const struct mailbox_settings *
mailbox_settings_find(struct mail_namespace *ns, const char *vname)
{
    struct mailbox_settings *const *box_set;

    if (!array_is_created(&ns->set->mailboxes))
        return NULL;

    if (ns->prefix_len > 0 &&
        strncmp(ns->prefix, vname, ns->prefix_len-1) == 0) {
        if (vname[ns->prefix_len-1] == mail_namespace_get_sep(ns))
            vname += ns->prefix_len;
        else if (vname[ns->prefix_len-1] == '\0') {
            /* namespace prefix itself */
            vname = "";
        }
    }
    array_foreach(&ns->set->mailboxes, box_set) {
        if (strcmp((*box_set)->name, vname) == 0)
            return *box_set;
    }
    return NULL;
}

struct mailbox *mailbox_alloc(struct mailbox_list *list, const char *vname,
                  enum mailbox_flags flags)
{
    struct mailbox_list *new_list = list;
    struct mail_storage *storage;
    struct mailbox *box;
    enum mail_error open_error = 0;
    const char *errstr = NULL;

    i_assert(uni_utf8_str_is_valid(vname));

    if (strncasecmp(vname, "INBOX", 5) == 0 &&
        strncmp(vname, "INBOX", 5) != 0) {
        /* make sure INBOX shows up in uppercase everywhere. do this
           regardless of whether we're in inbox=yes namespace, because
           clients expect INBOX to be case insensitive regardless of
           server's internal configuration. */
        if (vname[5] == '\0')
            vname = "INBOX";
        else if (vname[5] != mail_namespace_get_sep(list->ns))
            /* not INBOX prefix */ ;
        else if (strncasecmp(list->ns->prefix, vname, 6) == 0 &&
             strncmp(list->ns->prefix, "INBOX", 5) != 0) {
            mailbox_list_set_critical(list,
                "Invalid server configuration: "
                "Namespace prefix=%s must be uppercase INBOX",
                list->ns->prefix);
            open_error = MAIL_ERROR_TEMP;
        } else {
            vname = t_strconcat("INBOX", vname + 5, NULL);
        }
    }

    T_BEGIN {
        if (mailbox_list_get_storage(&new_list, vname, &storage) < 0) {
            /* do a delayed failure at mailbox_open() */
            storage = mail_namespace_get_default_storage(list->ns);
            errstr = mailbox_list_get_last_error(new_list, &open_error);
            errstr = t_strdup(errstr);
        }

        box = storage->v.mailbox_alloc(storage, new_list, vname, flags);
        box->set = mailbox_settings_find(new_list->ns, vname);
        box->open_error = open_error;
        if (open_error != 0)
            mail_storage_set_error(storage, open_error, errstr);
        hook_mailbox_allocated(box);
    } T_END;

    DLLIST_PREPEND(&box->storage->mailboxes, box);
    mail_storage_obj_ref(box->storage);
    return box;
}

struct mailbox *mailbox_alloc_guid(struct mailbox_list *list,
                   const guid_128_t guid,
                   enum mailbox_flags flags)
{
    struct mailbox *box = NULL;
    struct mailbox_metadata metadata;
    enum mail_error open_error = MAIL_ERROR_TEMP;
    const char *vname;

    if (mailbox_guid_cache_find(list, guid, &vname) < 0) {
        vname = NULL;
    } else if (vname != NULL) {
        box = mailbox_alloc(list, vname, flags);
        if (mailbox_get_metadata(box, MAILBOX_METADATA_GUID,
                     &metadata) < 0) {
        } else if (memcmp(metadata.guid, guid,
                  sizeof(metadata.guid)) != 0) {
            /* GUID mismatch, refresh cache and try again */
            mailbox_free(&box);
            mailbox_guid_cache_refresh(list);
            return mailbox_alloc_guid(list, guid, flags);
        } else {
            /* successfully opened the correct mailbox */
            return box;
        }
        i_error("mailbox_alloc_guid(%s): "
            "Couldn't verify mailbox GUID: %s",
            guid_128_to_string(guid),
            mailbox_get_last_error(box, NULL));
        vname = NULL;
        mailbox_free(&box);
    } else {
        vname = t_strdup_printf("(nonexistent mailbox with GUID=%s)",
                    guid_128_to_string(guid));
        open_error = MAIL_ERROR_NOTFOUND;
    }

    if (vname == NULL) {
        vname = t_strdup_printf("(error in mailbox with GUID=%s)",
                    guid_128_to_string(guid));
    }
    box = mailbox_alloc(list, vname, flags);
    box->open_error = open_error;
    return box;
}

static bool mailbox_is_autocreated(struct mailbox *box)
{
    if (box->inbox_user)
        return TRUE;
    return box->set != NULL &&
        strcmp(box->set->autocreate, MAILBOX_SET_AUTO_NO) != 0;
}

static int mailbox_autocreate(struct mailbox *box)
{
    const char *errstr;
    enum mail_error error;

    if (mailbox_create(box, NULL, FALSE) < 0) {
        errstr = mailbox_get_last_error(box, &error);
        if (error != MAIL_ERROR_EXISTS) {
            mail_storage_set_critical(box->storage,
                "Failed to autocreate mailbox %s: %s",
                box->vname, errstr);
            return -1;
        }
    } else if (box->set != NULL &&
           strcmp(box->set->autocreate,
              MAILBOX_SET_AUTO_SUBSCRIBE) == 0) {
        if (mailbox_set_subscribed(box, TRUE) < 0) {
            mail_storage_set_critical(box->storage,
                "Failed to autosubscribe to mailbox %s: %s",
                box->vname, mailbox_get_last_error(box, NULL));
            return -1;
        }
    }
    return 0;
}

static int mailbox_autocreate_and_reopen(struct mailbox *box)
{
    int ret;

    if (mailbox_autocreate(box) < 0)
        return -1;
    mailbox_close(box);

    ret = box->v.open(box);
    if (ret < 0 && box->inbox_user &&
        !box->storage->user->inbox_open_error_logged) {
        box->storage->user->inbox_open_error_logged = TRUE;
        mail_storage_set_critical(box->storage,
            "Opening INBOX failed: %s",
            mailbox_get_last_error(box, NULL));
    }
    return ret;
}

static bool
mailbox_name_verify_separators(const char *vname, char sep,
                   const char **error_r)
{
    unsigned int i;
    bool prev_sep = FALSE;

    /* Make sure the vname is correct: non-empty, doesn't begin or end
       with separator and no adjacent separators */
    for (i = 0; vname[i] != '\0'; i++) {
        if (vname[i] == sep) {
            if (prev_sep) {
                *error_r = "Has adjacent hierarchy separators";
                return FALSE;
            }
            prev_sep = TRUE;
        } else {
            prev_sep = FALSE;
        }
    }
    if (prev_sep && i > 0) {
        *error_r = "Ends with hierarchy separator";
        return FALSE;
    }
    return TRUE;
}

static int mailbox_verify_name(struct mailbox *box)
{
    struct mail_namespace *ns = box->list->ns;
    const char *error, *vname = box->vname;
    char list_sep, ns_sep;

    if (box->inbox_user) {
        /* this is INBOX - don't bother with further checks */
        return 0;
    }

    list_sep = mailbox_list_get_hierarchy_sep(box->list);
    ns_sep = mail_namespace_get_sep(ns);

    if (ns->prefix_len > 0) {
        /* vname is either "namespace/box" or "namespace" */
        if (strncmp(vname, ns->prefix, ns->prefix_len-1) != 0 ||
            (vname[ns->prefix_len-1] != '\0' &&
             vname[ns->prefix_len-1] != ns->prefix[ns->prefix_len-1])) {
            /* User input shouldn't normally be able to get us in
               here. The main reason this isn't an assert is to
               allow any input at all to mailbox_verify_*_name()
               without crashing. */
            mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS,
                t_strdup_printf("Invalid mailbox name '%s': "
                    "Missing namespace prefix '%s'",
                    str_sanitize(vname, 80), ns->prefix));
            return -1;
        }
        vname += ns->prefix_len - 1;
        if (vname[0] != '\0') {
            i_assert(vname[0] == ns->prefix[ns->prefix_len-1]);
            vname++;

            if (vname[0] == '\0') {
                /* "namespace/" isn't a valid mailbox name. */
                mail_storage_set_error(box->storage,
                               MAIL_ERROR_PARAMS,
                               "Invalid mailbox name");
                return -1;
            }
        }
    }

    if (ns_sep != list_sep && box->list->set.escape_char == '\0' &&
        strchr(vname, list_sep) != NULL) {
        mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS, t_strdup_printf(
            "Character not allowed in mailbox name: '%c'", list_sep));
        return -1;
    }
    if (vname[0] == ns_sep &&
        !box->storage->set->mail_full_filesystem_access) {
        mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS,
            "Invalid mailbox name: Begins with hierarchy separator");
        return -1;
    }

    if (!mailbox_name_verify_separators(vname, ns_sep, &error) ||
        !mailbox_list_is_valid_name(box->list, box->name, &error)) {
        mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS,
            t_strdup_printf("Invalid mailbox name: %s", error));
        return -1;
    }
    return 0;
}

static int mailbox_verify_existing_name(struct mailbox *box)
{
    const char *path;

    if (box->opened)
        return 0;

    if (mailbox_verify_name(box) < 0)
        return -1;

    /* Make sure box->_path is set, so mailbox_get_path() works from
       now on. Note that this may also fail with some backends if the
       mailbox doesn't exist. */
    if (mailbox_get_path_to(box, MAILBOX_LIST_PATH_TYPE_MAILBOX, &path) < 0) {
        if (box->storage->error != MAIL_ERROR_NOTFOUND ||
            !mailbox_is_autocreated(box))
            return -1;
        /* if this is an autocreated mailbox, create it now */
        if (mailbox_autocreate(box) < 0)
            return -1;
        mailbox_close(box);
        if (mailbox_get_path_to(box, MAILBOX_LIST_PATH_TYPE_MAILBOX,
                    &path) < 0)
            return -1;
    }
    return 0;
}

static bool mailbox_name_has_control_chars(const char *name)
{
    const char *p;

    for (p = name; *p != '\0'; p++) {
        if ((unsigned char)*p < ' ')
            return TRUE;
    }
    return FALSE;
}

void mailbox_skip_create_name_restrictions(struct mailbox *box, bool set)
{
    box->skip_create_name_restrictions = set;
}

int mailbox_verify_create_name(struct mailbox *box)
{
    char sep = mail_namespace_get_sep(box->list->ns);

    /* mailbox_alloc() already checks that vname is valid UTF8,
       so we don't need to verify that.

       check vname instead of storage name, because vname is what is
       visible to users, while storage name may be a fixed length GUID. */
    if (mailbox_verify_name(box) < 0)
        return -1;
    if (box->skip_create_name_restrictions)
        return 0;
    if (mailbox_name_has_control_chars(box->vname)) {
        mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS,
            "Control characters not allowed in new mailbox names");
        return -1;
    }
    if (mailbox_list_name_is_too_large(box->vname, sep)) {
        mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS,
                       "Mailbox name too long");
        return -1;
    }
    return 0;
}

static bool have_listable_namespace_prefix(struct mail_namespace *ns,
                       const char *name)
{
    unsigned int name_len = strlen(name);

    for (; ns != NULL; ns = ns->next) {
        if ((ns->flags & (NAMESPACE_FLAG_LIST_PREFIX |
                  NAMESPACE_FLAG_LIST_CHILDREN)) == 0)
            continue;

        if (ns->prefix_len <= name_len)
            continue;

        /* if prefix has multiple hierarchies, match
           any of the hierarchies */
        if (strncmp(ns->prefix, name, name_len) == 0 &&
            ns->prefix[name_len] == mail_namespace_get_sep(ns))
            return TRUE;
    }
    return FALSE;
}

int mailbox_exists(struct mailbox *box, bool auto_boxes,
           enum mailbox_existence *existence_r)
{
    switch (box->open_error) {
    case 0:
        break;
    case MAIL_ERROR_NOTFOUND:
        *existence_r = MAILBOX_EXISTENCE_NONE;
        return 0;
    default:
        /* unsure if this exists or not */
        return -1;
    }
    if (mailbox_verify_name(box) < 0) {
        /* the mailbox name is invalid. we don't know if it currently
           exists or not, but since it can never be accessed in any way
           report it as if it didn't exist. */
        *existence_r = MAILBOX_EXISTENCE_NONE;
        return 0;
    }

    if (auto_boxes && mailbox_is_autocreated(box)) {
        *existence_r = MAILBOX_EXISTENCE_SELECT;
        return 0;
    }

    if (box->v.exists(box, auto_boxes, existence_r) < 0)
        return -1;

    if (!box->inbox_user && *existence_r == MAILBOX_EXISTENCE_NOSELECT &&
        have_listable_namespace_prefix(box->storage->user->namespaces,
                       box->vname)) {
           /* listable namespace prefix always exists. */
        *existence_r = MAILBOX_EXISTENCE_NOSELECT;
        return 0;
    }

    /* if this is a shared namespace with only INBOX and
       mail_shared_explicit_inbox=no, we'll need to mark the namespace as
       usable here since nothing else will. */
    box->list->ns->flags |= NAMESPACE_FLAG_USABLE;
    return 0;
}

static int ATTR_NULL(2)
mailbox_open_full(struct mailbox *box, struct istream *input)
{
    int ret;

    if (box->opened)
        return 0;
    switch (box->open_error) {
    case 0:
        break;
    case MAIL_ERROR_NOTFOUND:
        mail_storage_set_error(box->storage, MAIL_ERROR_NOTFOUND,
            T_MAIL_ERR_MAILBOX_NOT_FOUND(box->vname));
        return -1;
    default:
        mail_storage_set_internal_error(box->storage);
        box->storage->error = box->open_error;
        return -1;
    }

    if (mailbox_verify_existing_name(box) < 0)
        return -1;

    if (input != NULL) {
        if ((box->storage->class_flags &
             MAIL_STORAGE_CLASS_FLAG_OPEN_STREAMS) == 0) {
            mail_storage_set_critical(box->storage,
                "Storage doesn't support streamed mailboxes");
            return -1;
        }
        box->input = input;
        box->flags |= MAILBOX_FLAG_READONLY;
        i_stream_ref(box->input);
    }

    T_BEGIN {
        ret = box->v.open(box);
    } T_END;

    if (ret < 0 && box->storage->error == MAIL_ERROR_NOTFOUND &&
        box->input == NULL && mailbox_is_autocreated(box)) T_BEGIN {
        ret = mailbox_autocreate_and_reopen(box);
    } T_END;

    if (ret < 0) {
        if (box->input != NULL)
            i_stream_unref(&box->input);
        return -1;
    }

    box->list->ns->flags |= NAMESPACE_FLAG_USABLE;
    return 0;
}

static bool mailbox_try_undelete(struct mailbox *box)
{
    time_t mtime;

    if ((box->flags & MAILBOX_FLAG_READONLY) != 0) {
        /* most importantly we don't do this because we want to avoid
           a loop: mdbox storage rebuild -> mailbox_open() ->
           mailbox_mark_index_deleted() -> mailbox_sync() ->
           mdbox storage rebuild. */
        return FALSE;
    }
    if (mail_index_get_modification_time(box->index, &mtime) < 0)
        return FALSE;
    if (mtime + MAILBOX_DELETE_RETRY_SECS > time(NULL))
        return FALSE;

    if (mailbox_mark_index_deleted(box, FALSE) < 0)
        return FALSE;
    box->mailbox_deleted = FALSE;
    return TRUE;
}

int mailbox_open(struct mailbox *box)
{
    if (mailbox_open_full(box, NULL) < 0) {
        if (!box->mailbox_deleted)
            return -1;

        /* mailbox has been marked as deleted. if this deletion
           started (and crashed) a long time ago, it can be confusing
           to user that the mailbox can't be opened. so we'll just
           undelete it and reopen. */
        if(!mailbox_try_undelete(box))
            return -1;
        if (mailbox_open_full(box, NULL) < 0)
            return -1;
    }
    return 0;
}

static int mailbox_alloc_index_pvt(struct mailbox *box)
{
    const char *index_dir;
    int ret;

    if (box->index_pvt != NULL)
        return 1;

    ret = mailbox_get_path_to(box, MAILBOX_LIST_PATH_TYPE_INDEX_PRIVATE,
                  &index_dir);
    if (ret <= 0)
        return ret; /* error / no private indexes */

    if (mailbox_create_missing_dir(box, MAILBOX_LIST_PATH_TYPE_INDEX_PRIVATE) < 0)
        return -1;

    box->index_pvt = mail_index_alloc_cache_get(NULL, index_dir,
        t_strconcat(box->index_prefix, ".pvt", NULL));
    mail_index_set_fsync_mode(box->index_pvt,
                  box->storage->set->parsed_fsync_mode, 0);
    mail_index_set_lock_method(box->index_pvt,
        box->storage->set->parsed_lock_method,
        mail_storage_get_lock_timeout(box->storage, UINT_MAX));
    return 1;
}

int mailbox_open_index_pvt(struct mailbox *box)
{
    enum mail_index_open_flags index_flags;
    int ret;

    if (box->view_pvt != NULL)
        return 1;
    if (mailbox_get_private_flags_mask(box) == 0)
        return 0;

    if ((ret = mailbox_alloc_index_pvt(box)) <= 0)
        return ret;
    index_flags = MAIL_INDEX_OPEN_FLAG_CREATE |
        mail_storage_settings_to_index_flags(box->storage->set);
    if ((box->flags & MAILBOX_FLAG_SAVEONLY) != 0)
        index_flags |= MAIL_INDEX_OPEN_FLAG_SAVEONLY;
    if (mail_index_open(box->index_pvt, index_flags) < 0)
        return -1;
    box->view_pvt = mail_index_view_open(box->index_pvt);
    return 1;
}

int mailbox_open_stream(struct mailbox *box, struct istream *input)
{
    return mailbox_open_full(box, input);
}

int mailbox_enable(struct mailbox *box, enum mailbox_feature features)
{
    if (mailbox_verify_name(box) < 0)
        return -1;
    return box->v.enable(box, features);
}

enum mailbox_feature mailbox_get_enabled_features(struct mailbox *box)
{
    return box->enabled_features;
}

void mail_storage_free_binary_cache(struct mail_storage *storage)
{
    if (storage->binary_cache.box == NULL)
        return;

    timeout_remove(&storage->binary_cache.to);
    i_stream_destroy(&storage->binary_cache.input);
    memset(&storage->binary_cache, 0, sizeof(storage->binary_cache));
}

void mailbox_close(struct mailbox *box)
{
    if (!box->opened)
        return;

    if (box->transaction_count != 0) {
        i_panic("Trying to close mailbox %s with open transactions",
            box->name);
    }
    box->v.close(box);

    if (box->storage->binary_cache.box == box)
        mail_storage_free_binary_cache(box->storage);
    box->opened = FALSE;
    box->mailbox_deleted = FALSE;
    array_clear(&box->search_results);

    if (array_is_created(&box->recent_flags))
        array_free(&box->recent_flags);
    box->recent_flags_prev_uid = 0;
    box->recent_flags_count = 0;
}

void mailbox_free(struct mailbox **_box)
{
    struct mailbox *box = *_box;

    *_box = NULL;

    mailbox_close(box);
    box->v.free(box);

    DLLIST_REMOVE(&box->storage->mailboxes, box);
    mail_storage_obj_unref(box->storage);
    if (box->metadata_pool != NULL)
        pool_unref(&box->metadata_pool);
    pool_unref(&box->pool);
}

bool mailbox_equals(const struct mailbox *box1,
            const struct mail_namespace *ns2, const char *vname2)
{
    struct mail_namespace *ns1 = mailbox_get_namespace(box1);
    const char *name1;

    if (ns1 != ns2)
        return FALSE;

        name1 = mailbox_get_vname(box1);
    if (strcmp(name1, vname2) == 0)
        return TRUE;

    return strcasecmp(name1, "INBOX") == 0 &&
        strcasecmp(vname2, "INBOX") == 0;
}

bool mailbox_is_any_inbox(struct mailbox *box)
{
    return box->inbox_any;
}

int mailbox_create(struct mailbox *box, const struct mailbox_update *update,
           bool directory)
{
    int ret;

    if (mailbox_verify_create_name(box) < 0)
        return -1;

    box->creating = TRUE;
    ret = box->v.create_box(box, update, directory);
    box->creating = FALSE;
    if (ret == 0)
        box->list->guid_cache_updated = TRUE;
    return ret;
}

int mailbox_update(struct mailbox *box, const struct mailbox_update *update)
{
    int ret;

    i_assert(update->min_next_uid == 0 ||
         update->min_first_recent_uid == 0 ||
         update->min_first_recent_uid <= update->min_next_uid);

    if (mailbox_verify_existing_name(box) < 0)
        return -1;
    ret = box->v.update_box(box, update);
    if (!guid_128_is_empty(update->mailbox_guid))
        box->list->guid_cache_invalidated = TRUE;
    return ret;
}

int mailbox_mark_index_deleted(struct mailbox *box, bool del)
{
    struct mail_index_transaction *trans;
    enum mail_index_transaction_flags trans_flags = 0;
    enum mailbox_flags old_flag;
    int ret;

    if (box->marked_deleted && del) {
        /* we already marked it deleted. this allows plugins to
           "lock" the deletion earlier. */
        return 0;
    }

    old_flag = box->flags & MAILBOX_FLAG_OPEN_DELETED;
    box->flags |= MAILBOX_FLAG_OPEN_DELETED;
    ret = mailbox_open(box);
    box->flags = (box->flags & ~MAILBOX_FLAG_OPEN_DELETED) | old_flag;
    if (ret < 0)
        return -1;

    trans_flags = del ? 0 : MAIL_INDEX_TRANSACTION_FLAG_EXTERNAL;
    trans = mail_index_transaction_begin(box->view, trans_flags);
    if (del)
        mail_index_set_deleted(trans);
    else
        mail_index_set_undeleted(trans);
    if (mail_index_transaction_commit(&trans) < 0) {
        mailbox_set_index_error(box);
        return -1;
    }

    /* sync the mailbox. this finishes the index deletion and it can
       succeed only for a single session. we do it here, so the rest of
       the deletion code doesn't have to worry about race conditions. */
    box->delete_sync_check = TRUE;
    ret = mailbox_sync(box, MAILBOX_SYNC_FLAG_FULL_READ);
    box->delete_sync_check = FALSE;
    if (ret < 0)
        return -1;

    box->marked_deleted = del;
    return 0;
}

static void mailbox_close_reset_path(struct mailbox *box)
{
    memset(&box->_perm, 0, sizeof(box->_perm));
    box->_path = NULL;
    box->_index_path = NULL;
}

int mailbox_delete(struct mailbox *box)
{
    int ret;

    if (*box->name == '\0') {
        mail_storage_set_error(box->storage, MAIL_ERROR_PARAMS,
                       "Storage root can't be deleted");
        return -1;
    }

    box->deleting = TRUE;
    if (mailbox_open(box) < 0) {
        if (mailbox_get_last_mail_error(box) != MAIL_ERROR_NOTFOUND &&
            !box->mailbox_deleted)
            return -1;
        /* \noselect mailbox */
    }

    ret = box->v.delete_box(box);
    if (ret < 0 && box->marked_deleted) {
        /* deletion failed. revert the mark so it can maybe be
           tried again later. */
        if (mailbox_mark_index_deleted(box, FALSE) < 0)
            return -1;
    }

    box->deleting = FALSE;
    mailbox_close(box);

    /* if mailbox is reopened, its path may be different with
       LAYOUT=index */
    mailbox_close_reset_path(box);
    return ret;
}

int mailbox_delete_empty(struct mailbox *box)
{
    int ret;

    /* FIXME: should be a parameter to delete(), but since it changes API
       don't do it for now */
    box->deleting_must_be_empty = TRUE;
    ret = mailbox_delete(box);
    box->deleting_must_be_empty = FALSE;
    return ret;
}

static bool
mail_storages_rename_compatible(struct mail_storage *storage1,
                struct mail_storage *storage2,
                const char **error_r)
{
    if (storage1 == storage2)
        return TRUE;

    if (strcmp(storage1->name, storage2->name) != 0) {
        *error_r = t_strdup_printf("storage %s != %s",
                       storage1->name, storage2->name);
        return FALSE;
    }
    if ((storage1->class_flags & MAIL_STORAGE_CLASS_FLAG_UNIQUE_ROOT) != 0) {
        /* e.g. mdbox where all mails are in storage/ directory and
           they can't be easily moved from there. */
        *error_r = t_strdup_printf("storage %s uses unique root",
                       storage1->name);
        return FALSE;
    }
    return TRUE;
}

static bool nullequals(const void *p1, const void *p2)
{
    return (p1 == NULL && p2 == NULL) || (p1 != NULL && p2 != NULL);
}

static bool
mailbox_lists_rename_compatible(struct mailbox_list *list1,
                struct mailbox_list *list2,
                const char **error_r)
{
    if (!nullequals(list1->set.alt_dir, list2->set.alt_dir)) {
        *error_r = "one namespace has alt dir and another doesn't";
        return FALSE;
    }
    if (!nullequals(list1->set.index_dir, list2->set.index_dir)) {
        *error_r = "one namespace has index dir and another doesn't";
        return FALSE;
    }
    if (!nullequals(list1->set.control_dir, list2->set.control_dir)) {
        *error_r = "one namespace has control dir and another doesn't";
        return FALSE;
    }
    return TRUE;
}

int mailbox_rename(struct mailbox *src, struct mailbox *dest)
{
    const char *error = NULL;

    /* Check only name validity, \Noselect don't necessarily exist. */
    if (mailbox_verify_name(src) < 0)
        return -1;
    if (*src->name == '\0') {
        mail_storage_set_error(src->storage, MAIL_ERROR_PARAMS,
                       "Can't rename mailbox root");
        return -1;
    }
    if (mailbox_verify_create_name(dest) < 0) {
        mail_storage_copy_error(dest->storage, src->storage);
        return -1;
    }
    if (!mail_storages_rename_compatible(src->storage,
                         dest->storage, &error) ||
        !mailbox_lists_rename_compatible(src->list,
                         dest->list, &error)) {
        if (src->storage->set->mail_debug) {
            i_debug("Can't rename '%s' to '%s': %s",
                src->vname, dest->vname, error);
        }
        mail_storage_set_error(src->storage, MAIL_ERROR_NOTPOSSIBLE,
            "Can't rename mailboxes across specified storages.");
        return -1;
    }
    if (src->list != dest->list &&
        (src->list->ns->type != MAIL_NAMESPACE_TYPE_PRIVATE ||
         dest->list->ns->type != MAIL_NAMESPACE_TYPE_PRIVATE)) {
        mail_storage_set_error(src->storage, MAIL_ERROR_NOTPOSSIBLE,
            "Renaming not supported across non-private namespaces.");
        return -1;
    }
    if (src->list == dest->list && strcmp(src->name, dest->name) == 0) {
        mail_storage_set_error(src->storage, MAIL_ERROR_EXISTS,
                       "Can't rename mailbox to itself.");
        return -1;
    }

    if (src->v.rename_box(src, dest) < 0)
        return -1;
    src->list->guid_cache_invalidated = TRUE;
    dest->list->guid_cache_invalidated = TRUE;
    return 0;
}

int mailbox_set_subscribed(struct mailbox *box, bool set)
{
    if (mailbox_verify_name(box) < 0)
        return -1;
    return box->v.set_subscribed(box, set);
}

bool mailbox_is_subscribed(struct mailbox *box)
{
    struct mailbox_node *node;

    i_assert(box->list->subscriptions != NULL);

    node = mailbox_tree_lookup(box->list->subscriptions, box->vname);
    return node != NULL && (node->flags & MAILBOX_SUBSCRIBED) != 0;
}

struct mail_storage *mailbox_get_storage(const struct mailbox *box)
{
    return box->storage;
}

struct mail_namespace *
mailbox_get_namespace(const struct mailbox *box)
{
    return box->list->ns;
}

const struct mail_storage_settings *mailbox_get_settings(struct mailbox *box)
{
    return box->storage->set;
}

const char *mailbox_get_name(const struct mailbox *box)
{
    return box->name;
}

const char *mailbox_get_vname(const struct mailbox *box)
{
    return box->vname;
}

bool mailbox_is_readonly(struct mailbox *box)
{
    i_assert(box->opened);

    return box->v.is_readonly(box);
}

bool mailbox_backends_equal(const struct mailbox *box1,
                const struct mailbox *box2)
{
    struct mail_namespace *ns1 = box1->list->ns, *ns2 = box2->list->ns;

    if (strcmp(box1->name, box2->name) != 0)
        return FALSE;

    while (ns1->alias_for != NULL)
        ns1 = ns1->alias_for;
    while (ns2->alias_for != NULL)
        ns2 = ns2->alias_for;
    return ns1 == ns2;
}

static void
mailbox_get_status_set_defaults(struct mailbox *box,
                struct mailbox_status *status_r)
{
    memset(status_r, 0, sizeof(*status_r));
    if ((box->storage->class_flags & MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_GUIDS) != 0)
        status_r->have_guids = TRUE;
    if ((box->storage->class_flags & MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_SAVE_GUIDS) != 0)
        status_r->have_save_guids = TRUE;
    if ((box->storage->class_flags & MAIL_STORAGE_CLASS_FLAG_HAVE_MAIL_GUID128) != 0)
        status_r->have_only_guid128 = TRUE;
}

int mailbox_get_status(struct mailbox *box,
               enum mailbox_status_items items,
               struct mailbox_status *status_r)
{
    mailbox_get_status_set_defaults(box, status_r);
    if (mailbox_verify_existing_name(box) < 0)
        return -1;

    if ((items & STATUS_HIGHESTMODSEQ) != 0)
        mailbox_enable(box, MAILBOX_FEATURE_CONDSTORE);
    if (box->v.get_status(box, items, status_r) < 0)
        return -1;
    i_assert(status_r->have_guids || !status_r->have_save_guids);
    return 0;
}

void mailbox_get_open_status(struct mailbox *box,
                 enum mailbox_status_items items,
                 struct mailbox_status *status_r)
{
    i_assert(box->opened);
    i_assert((items & MAILBOX_STATUS_FAILING_ITEMS) == 0);

    mailbox_get_status_set_defaults(box, status_r);
    if ((items & STATUS_HIGHESTMODSEQ) != 0)
        mailbox_enable(box, MAILBOX_FEATURE_CONDSTORE);
    if (box->v.get_status(box, items, status_r) < 0)
        i_unreached();
}

int mailbox_get_metadata(struct mailbox *box, enum mailbox_metadata_items items,
             struct mailbox_metadata *metadata_r)
{
    memset(metadata_r, 0, sizeof(*metadata_r));
    if (mailbox_verify_existing_name(box) < 0)
        return -1;

    if (box->metadata_pool != NULL)
        p_clear(box->metadata_pool);

    if (box->v.get_metadata(box, items, metadata_r) < 0)
        return -1;

    i_assert((items & MAILBOX_METADATA_GUID) == 0 ||
         !guid_128_is_empty(metadata_r->guid));
    return 0;
}

enum mail_flags mailbox_get_private_flags_mask(struct mailbox *box)
{
    if (box->v.get_private_flags_mask != NULL)
        return box->v.get_private_flags_mask(box);
    else if (box->list->set.index_pvt_dir != NULL)
        return MAIL_SEEN; /* FIXME */
    else
        return 0;
}

struct mailbox_sync_context *
mailbox_sync_init(struct mailbox *box, enum mailbox_sync_flags flags)
{
    struct mailbox_sync_context *ctx;

    if (box->transaction_count != 0) {
        i_panic("Trying to sync mailbox %s with open transactions",
            box->name);
    }
    T_BEGIN {
        ctx = box->v.sync_init(box, flags);
    } T_END;
    return ctx;
}

bool mailbox_sync_next(struct mailbox_sync_context *ctx,
               struct mailbox_sync_rec *sync_rec_r)
{
    return ctx->box->v.sync_next(ctx, sync_rec_r);
}

int mailbox_sync_deinit(struct mailbox_sync_context **_ctx,
            struct mailbox_sync_status *status_r)
{
    struct mailbox_sync_context *ctx = *_ctx;
    struct mailbox *box = ctx->box;
    const char *errormsg;
    enum mail_error error;
    int ret;

    *_ctx = NULL;

    memset(status_r, 0, sizeof(*status_r));
    ret = box->v.sync_deinit(ctx, status_r);
    if (ret < 0 && box->inbox_user &&
        !box->storage->user->inbox_open_error_logged) {
        errormsg = mailbox_get_last_error(box, &error);
        if (error == MAIL_ERROR_NOTPOSSIBLE) {
            box->storage->user->inbox_open_error_logged = TRUE;
            i_error("Syncing INBOX failed: %s", errormsg);
        }
    }
    if (ret == 0)
        box->synced = TRUE;
    return ret;
}

int mailbox_sync(struct mailbox *box, enum mailbox_sync_flags flags)
{
    struct mailbox_sync_context *ctx;
    struct mailbox_sync_status status;

    if (array_count(&box->search_results) == 0) {
        /* we don't care about mailbox's current state, so we might
           as well fix inconsistency state */
        flags |= MAILBOX_SYNC_FLAG_FIX_INCONSISTENT;
    }

    ctx = mailbox_sync_init(box, flags);
    return mailbox_sync_deinit(&ctx, &status);
}

#undef mailbox_notify_changes
void mailbox_notify_changes(struct mailbox *box,
                mailbox_notify_callback_t *callback, void *context)
{
    i_assert(box->opened);

    box->notify_callback = callback;
    box->notify_context = context;

    box->v.notify_changes(box);
}

void mailbox_notify_changes_stop(struct mailbox *box)
{
    i_assert(box->opened);

    box->notify_callback = NULL;
    box->notify_context = NULL;

    box->v.notify_changes(box);
}

struct mail_search_context *
mailbox_search_init(struct mailbox_transaction_context *t,
            struct mail_search_args *args,
            const enum mail_sort_type *sort_program,
            enum mail_fetch_field wanted_fields,
            struct mailbox_header_lookup_ctx *wanted_headers)
{
    mail_search_args_ref(args);
    if (!args->simplified)
        mail_search_args_simplify(args);
    return t->box->v.search_init(t, args, sort_program,
                     wanted_fields, wanted_headers);
}

int mailbox_search_deinit(struct mail_search_context **_ctx)
{
    struct mail_search_context *ctx = *_ctx;
    struct mail_search_args *args = ctx->args;
    int ret;

    *_ctx = NULL;
    mailbox_search_results_initial_done(ctx);
    ret = ctx->transaction->box->v.search_deinit(ctx);
    mail_search_args_unref(&args);
    return ret;
}

bool mailbox_search_next(struct mail_search_context *ctx, struct mail **mail_r)
{
    bool tryagain;

    while (!mailbox_search_next_nonblock(ctx, mail_r, &tryagain)) {
        if (!tryagain)
            return FALSE;
    }
    return TRUE;
}

bool mailbox_search_next_nonblock(struct mail_search_context *ctx,
                  struct mail **mail_r, bool *tryagain_r)
{
    struct mailbox *box = ctx->transaction->box;

    *mail_r = NULL;
    *tryagain_r = FALSE;

    if (!box->v.search_next_nonblock(ctx, mail_r, tryagain_r))
        return FALSE;
    else {
        mailbox_search_results_add(ctx, (*mail_r)->uid);
        return TRUE;
    }
}

bool mailbox_search_seen_lost_data(struct mail_search_context *ctx)
{
    return ctx->seen_lost_data;
}

int mailbox_search_result_build(struct mailbox_transaction_context *t,
                struct mail_search_args *args,
                enum mailbox_search_result_flags flags,
                struct mail_search_result **result_r)
{
    struct mail_search_context *ctx;
    struct mail *mail;
    int ret;

    ctx = mailbox_search_init(t, args, NULL, 0, NULL);
    *result_r = mailbox_search_result_save(ctx, flags);
    while (mailbox_search_next(ctx, &mail)) ;

    ret = mailbox_search_deinit(&ctx);
    if (ret < 0)
        mailbox_search_result_free(result_r);
    return ret;
}

struct mailbox_transaction_context *
mailbox_transaction_begin(struct mailbox *box,
              enum mailbox_transaction_flags flags)
{
    struct mailbox_transaction_context *trans;

    i_assert(box->opened);

    box->transaction_count++;
    trans = box->v.transaction_begin(box, flags);
    trans->flags = flags;
    return trans;
}

int mailbox_transaction_commit(struct mailbox_transaction_context **t)
{
    struct mail_transaction_commit_changes changes;
    int ret;

    /* Store changes temporarily so that plugins overriding
       transaction_commit() can look at them. */
    ret = mailbox_transaction_commit_get_changes(t, &changes);
    if (changes.pool != NULL)
        pool_unref(&changes.pool);
    return ret;
}

int mailbox_transaction_commit_get_changes(
    struct mailbox_transaction_context **_t,
    struct mail_transaction_commit_changes *changes_r)
{
    struct mailbox_transaction_context *t = *_t;
    struct mailbox *box = t->box;
    unsigned int save_count = t->save_count;
    int ret;

    changes_r->pool = NULL;

    *_t = NULL;
    T_BEGIN {
        ret = box->v.transaction_commit(t, changes_r);
    } T_END;
    /* either all the saved messages get UIDs or none, because a) we
       failed, b) MAILBOX_TRANSACTION_FLAG_ASSIGN_UIDS not set,
       c) backend doesn't support it (e.g. virtual plugin) */
    i_assert(ret < 0 ||
         seq_range_count(&changes_r->saved_uids) == save_count ||
         array_count(&changes_r->saved_uids) == 0);
    /* decrease the transaction count only after transaction_commit().
       that way if it creates and destroys transactions internally, we
       don't see transaction_count=0 until the parent transaction is fully
       finished */
    box->transaction_count--;
    if (ret < 0 && changes_r->pool != NULL)
        pool_unref(&changes_r->pool);
    return ret;
}

void mailbox_transaction_rollback(struct mailbox_transaction_context **_t)
{
    struct mailbox_transaction_context *t = *_t;
    struct mailbox *box = t->box;

    *_t = NULL;
    box->v.transaction_rollback(t);
    box->transaction_count--;
}

unsigned int mailbox_transaction_get_count(const struct mailbox *box)
{
    return box->transaction_count;
}

void mailbox_transaction_set_max_modseq(struct mailbox_transaction_context *t,
                    uint64_t max_modseq,
                    ARRAY_TYPE(seq_range) *seqs)
{
    mail_index_transaction_set_max_modseq(t->itrans, max_modseq, seqs);
}

struct mailbox *
mailbox_transaction_get_mailbox(const struct mailbox_transaction_context *t)
{
    return t->box;
}

struct mail_save_context *
mailbox_save_alloc(struct mailbox_transaction_context *t)
{
    struct mail_save_context *ctx;

    T_BEGIN {
        ctx = t->box->v.save_alloc(t);
    } T_END;
    i_assert(!ctx->unfinished);
    ctx->unfinished = TRUE;
    ctx->data.received_date = (time_t)-1;
    ctx->data.save_date = (time_t)-1;
    return ctx;
}

void mailbox_save_set_flags(struct mail_save_context *ctx,
                enum mail_flags flags,
                struct mail_keywords *keywords)
{
    struct mailbox *box = ctx->transaction->box;

    if (ctx->data.keywords != NULL)
        mailbox_keywords_unref(&ctx->data.keywords);

    ctx->data.flags = flags & ~mailbox_get_private_flags_mask(box);
    ctx->data.pvt_flags = flags & mailbox_get_private_flags_mask(box);
    ctx->data.keywords = keywords;
    if (keywords != NULL)
        mailbox_keywords_ref(keywords);
}

void mailbox_save_copy_flags(struct mail_save_context *ctx, struct mail *mail)
{
    const char *const *keywords_list;
    struct mail_keywords *keywords;

    keywords_list = mail_get_keywords(mail);
    keywords = str_array_length(keywords_list) == 0 ? NULL :
        mailbox_keywords_create_valid(ctx->transaction->box,
                          keywords_list);
    mailbox_save_set_flags(ctx, mail_get_flags(mail), keywords);
    if (keywords != NULL)
        mailbox_keywords_unref(&keywords);
}

void mailbox_save_set_min_modseq(struct mail_save_context *ctx,
                 uint64_t min_modseq)
{
    ctx->data.min_modseq = min_modseq;
}

void mailbox_save_set_received_date(struct mail_save_context *ctx,
                    time_t received_date, int timezone_offset)
{
    ctx->data.received_date = received_date;
    ctx->data.received_tz_offset = timezone_offset;
}

void mailbox_save_set_save_date(struct mail_save_context *ctx,
                time_t save_date)
{
    ctx->data.save_date = save_date;
}

void mailbox_save_set_from_envelope(struct mail_save_context *ctx,
                    const char *envelope)
{
    i_free(ctx->data.from_envelope);
    ctx->data.from_envelope = i_strdup(envelope);
}

void mailbox_save_set_uid(struct mail_save_context *ctx, uint32_t uid)
{
    ctx->data.uid = uid;
}

void mailbox_save_set_guid(struct mail_save_context *ctx, const char *guid)
{
    i_assert(guid == NULL || *guid != '\0');

    i_free(ctx->data.guid);
    ctx->data.guid = i_strdup(guid);
}

void mailbox_save_set_pop3_uidl(struct mail_save_context *ctx, const char *uidl)
{
    i_assert(*uidl != '\0');
    i_assert(strchr(uidl, '\n') == NULL);

    i_free(ctx->data.pop3_uidl);
    ctx->data.pop3_uidl = i_strdup(uidl);
}

void mailbox_save_set_pop3_order(struct mail_save_context *ctx,
                 unsigned int order)
{
    i_assert(order > 0);

    ctx->data.pop3_order = order;
}

void mailbox_save_set_dest_mail(struct mail_save_context *ctx,
                struct mail *mail)
{
    ctx->dest_mail = mail;
}

int mailbox_save_begin(struct mail_save_context **ctx, struct istream *input)
{
    struct mailbox *box = (*ctx)->transaction->box;
    int ret;

    if (mail_index_is_deleted(box->index)) {
        mailbox_set_deleted(box);
        mailbox_save_cancel(ctx);
        return -1;
    }

    if (!(*ctx)->copying_via_save)
        (*ctx)->saving = TRUE;
    if (box->v.save_begin == NULL) {
        mail_storage_set_error(box->storage, MAIL_ERROR_NOTPOSSIBLE,
                       "Saving messages not supported");
        ret = -1;
    } else T_BEGIN {
        ret = box->v.save_begin(*ctx, input);
    } T_END;

    if (ret < 0) {
        mailbox_save_cancel(ctx);
        return -1;
    }
    return 0;
}

int mailbox_save_continue(struct mail_save_context *ctx)
{
    int ret;

    T_BEGIN {
        ret = ctx->transaction->box->v.save_continue(ctx);
    } T_END;
    return ret;
}

static void
mailbox_save_add_pvt_flags(struct mailbox_transaction_context *t,
               enum mail_flags pvt_flags)
{
    struct mail_save_private_changes *save;

    if (!array_is_created(&t->pvt_saves))
        i_array_init(&t->pvt_saves, 8);
    save = array_append_space(&t->pvt_saves);
    save->mailnum = t->save_count;
    save->flags = pvt_flags;
}

int mailbox_save_finish(struct mail_save_context **_ctx)
{
    struct mail_save_context *ctx = *_ctx;
    struct mailbox_transaction_context *t = ctx->transaction;
    struct mail_keywords *keywords = ctx->data.keywords;
    enum mail_flags pvt_flags = ctx->data.pvt_flags;
    bool copying_via_save = ctx->copying_via_save;
    int ret;

    /* Do one final continue. The caller may not have done it if the
       input stream's offset already matched the number of bytes that
       were wanted to be saved. But due to nested istreams some of the
       underlying ones may not have seen the EOF yet, and haven't flushed
       out the pending data. */
    if (mailbox_save_continue(ctx) < 0) {
        mailbox_save_cancel(_ctx);
        return -1;
    }
    *_ctx = NULL;

    ctx->finishing = TRUE;
    T_BEGIN {
        ret = t->box->v.save_finish(ctx);
    } T_END;
    ctx->finishing = FALSE;

    if (ret == 0 && !copying_via_save) {
        if (pvt_flags != 0)
            mailbox_save_add_pvt_flags(t, pvt_flags);
        t->save_count++;
    }
    if (keywords != NULL)
        mailbox_keywords_unref(&keywords);
    i_assert(!ctx->unfinished);
    ctx->saving = FALSE;
    return ret;
}

void mailbox_save_cancel(struct mail_save_context **_ctx)
{
    struct mail_save_context *ctx = *_ctx;
    struct mail_keywords *keywords = ctx->data.keywords;
    struct mail_private *mail;

    *_ctx = NULL;
    T_BEGIN {
        ctx->transaction->box->v.save_cancel(ctx);
    } T_END;
    if (keywords != NULL && !ctx->finishing)
        mailbox_keywords_unref(&keywords);
    if (ctx->dest_mail != NULL) {
        /* the dest_mail is no longer valid. if we're still saving
           more mails, the mail sequence may get reused. make sure
           the mail gets reset in between */
        mail = (struct mail_private *)ctx->dest_mail;
        mail->v.close(&mail->mail);
    }
    i_assert(!ctx->unfinished);
    ctx->saving = FALSE;
}

struct mailbox_transaction_context *
mailbox_save_get_transaction(struct mail_save_context *ctx)
{
    return ctx->transaction;
}

int mailbox_copy(struct mail_save_context **_ctx, struct mail *mail)
{
    struct mail_save_context *ctx = *_ctx;
    struct mailbox_transaction_context *t = ctx->transaction;
    struct mail_keywords *keywords = ctx->data.keywords;
    enum mail_flags pvt_flags = ctx->data.pvt_flags;
    struct mail *backend_mail;
    int ret;

    *_ctx = NULL;

    if (mail_index_is_deleted(t->box->index)) {
        mailbox_set_deleted(t->box);
        mailbox_save_cancel(&ctx);
        return -1;
    }

    /* bypass virtual storage, so hard linking can be used whenever
       possible */
    if (mail_get_backend_mail(mail, &backend_mail) < 0) {
        mailbox_save_cancel(&ctx);
        return -1;
    }
    ctx->finishing = TRUE;
    T_BEGIN {
        ret = t->box->v.copy(ctx, backend_mail);
    } T_END;
    ctx->finishing = FALSE;
    if (ret == 0) {
        if (pvt_flags != 0)
            mailbox_save_add_pvt_flags(t, pvt_flags);
        t->save_count++;
    }
    if (keywords != NULL)
        mailbox_keywords_unref(&keywords);
    i_assert(!ctx->unfinished);

    ctx->copying_via_save = FALSE;
    ctx->saving = FALSE;
    return ret;
}

int mailbox_move(struct mail_save_context **_ctx, struct mail *mail)
{
    struct mail_save_context *ctx = *_ctx;

    ctx->moving = TRUE;
    if (mailbox_copy(_ctx, mail) < 0)
        return -1;

    mail_expunge(mail);
    ctx->moving = FALSE;
    return 0;
}

int mailbox_save_using_mail(struct mail_save_context **ctx, struct mail *mail)
{
    (*ctx)->saving = TRUE;
    return mailbox_copy(ctx, mail);
}

bool mailbox_is_inconsistent(struct mailbox *box)
{
    return box->mailbox_deleted || box->v.is_inconsistent(box);
}

void mailbox_set_deleted(struct mailbox *box)
{
    mail_storage_set_error(box->storage, MAIL_ERROR_NOTFOUND,
                   "Mailbox was deleted under us");
    box->mailbox_deleted = TRUE;
}

int mailbox_get_path_to(struct mailbox *box, enum mailbox_list_path_type type,
            const char **path_r)
{
    int ret;

    if (type == MAILBOX_LIST_PATH_TYPE_MAILBOX && box->_path != NULL) {
        if (box->_path[0] == '\0') {
            *path_r = NULL;
            return 0;
        }
        *path_r = box->_path;
        return 1;
    }
    if (type == MAILBOX_LIST_PATH_TYPE_INDEX && box->_index_path != NULL) {
        if (box->_index_path[0] == '\0') {
            *path_r = NULL;
            return 0;
        }
        *path_r = box->_index_path;
        return 1;
    }
    ret = mailbox_list_get_path(box->list, box->name, type, path_r);
    if (ret < 0) {
        mail_storage_copy_list_error(box->storage, box->list);
        return -1;
    }
    if (type == MAILBOX_LIST_PATH_TYPE_MAILBOX && box->_path == NULL)
        box->_path = ret == 0 ? "" : p_strdup(box->pool, *path_r);
    if (type == MAILBOX_LIST_PATH_TYPE_INDEX && box->_index_path == NULL)
        box->_index_path = ret == 0 ? "" : p_strdup(box->pool, *path_r);
    return ret;
}

const char *mailbox_get_path(struct mailbox *box)
{
    i_assert(box->_path != NULL);
    i_assert(box->_path[0] != '\0');
    return box->_path;
}

const char *mailbox_get_index_path(struct mailbox *box)
{
    i_assert(box->_index_path != NULL);
    i_assert(box->_index_path[0] != '\0');
    return box->_index_path;
}

static void mailbox_get_permissions_if_not_set(struct mailbox *box)
{
    if (box->_perm.file_create_mode != 0)
        return;

    if (box->input != NULL) {
        box->_perm.file_uid = geteuid();
        box->_perm.file_create_mode = 0600;
        box->_perm.dir_create_mode = 0700;
        box->_perm.file_create_gid = (gid_t)-1;
        box->_perm.file_create_gid_origin = "defaults";
        return;
    }

    mailbox_list_get_permissions(box->list, box->name, &box->_perm);
    box->_perm.file_create_gid_origin =
        p_strdup(box->pool, box->_perm.file_create_gid_origin);
}

const struct mailbox_permissions *mailbox_get_permissions(struct mailbox *box)
{
    mailbox_get_permissions_if_not_set(box);

    if (!box->_perm.mail_index_permissions_set && box->index != NULL) {
        box->_perm.mail_index_permissions_set = TRUE;
        mail_index_set_permissions(box->index,
                       box->_perm.file_create_mode,
                       box->_perm.file_create_gid,
                       box->_perm.file_create_gid_origin);
    }
    return &box->_perm;
}

void mailbox_refresh_permissions(struct mailbox *box)
{
    memset(&box->_perm, 0, sizeof(box->_perm));
    (void)mailbox_get_permissions(box);
}

int mailbox_create_fd(struct mailbox *box, const char *path, int flags,
              int *fd_r)
{
    const struct mailbox_permissions *perm = mailbox_get_permissions(box);
    mode_t old_mask;
    int fd;

    i_assert((flags & O_CREAT) != 0);

    *fd_r = -1;

    old_mask = umask(0);
    fd = open(path, flags, perm->file_create_mode);
    umask(old_mask);

    if (fd != -1) {
        /* ok */
    } else if (errno == EEXIST) {
        /* O_EXCL used, caller will handle this error */
        return 0;
    } else if (errno == ENOENT) {
        mailbox_set_deleted(box);
        return -1;
    } else if (errno == ENOTDIR) {
        mail_storage_set_error(box->storage, MAIL_ERROR_NOTPOSSIBLE,
            "Mailbox doesn't allow inferior mailboxes");
        return -1;
    } else if (mail_storage_set_error_from_errno(box->storage)) {
        return -1;
    } else {
        mail_storage_set_critical(box->storage,
            "open(%s, O_CREAT) failed: %m", path);
        return -1;
    }

    if (perm->file_create_gid != (gid_t)-1) {
        if (fchown(fd, (uid_t)-1, perm->file_create_gid) == 0) {
            /* ok */
        } else if (errno == EPERM) {
            mail_storage_set_critical(box->storage, "%s",
                eperm_error_get_chgrp("fchown", path,
                    perm->file_create_gid,
                    perm->file_create_gid_origin));
        } else {
            mail_storage_set_critical(box->storage,
                "fchown(%s) failed: %m", path);
        }
    }
    *fd_r = fd;
    return 1;
}

int mailbox_mkdir(struct mailbox *box, const char *path,
          enum mailbox_list_path_type type)
{
    const struct mailbox_permissions *perm = mailbox_get_permissions(box);
    const char *root_dir;

    if (!perm->gid_origin_is_mailbox_path) {
        /* mailbox root directory doesn't exist, create it */
        root_dir = mailbox_list_get_root_forced(box->list, type);
        if (mailbox_list_mkdir_root(box->list, root_dir, type) < 0) {
            mail_storage_copy_list_error(box->storage, box->list);
            return -1;
        }
    }

    if (mkdir_parents_chgrp(path, perm->dir_create_mode,
                perm->file_create_gid,
                perm->file_create_gid_origin) == 0)
        return 1;
    else if (errno == EEXIST)
        return 0;
    else if (errno == ENOTDIR) {
        mail_storage_set_error(box->storage, MAIL_ERROR_NOTPOSSIBLE,
            "Mailbox doesn't allow inferior mailboxes");
        return -1;
    } else if (mail_storage_set_error_from_errno(box->storage)) {
        return -1;
    } else {
        mail_storage_set_critical(box->storage,
                      "mkdir_parents(%s) failed: %m", path);
        return -1;
    }
}

int mailbox_create_missing_dir(struct mailbox *box,
                   enum mailbox_list_path_type type)
{
    const char *mail_dir, *dir;
    struct stat st;
    int ret;

    if ((ret = mailbox_get_path_to(box, type, &dir)) <= 0)
        return ret;
    if (mailbox_get_path_to(box, MAILBOX_LIST_PATH_TYPE_MAILBOX,
                &mail_dir) < 0)
        return -1;
    if (null_strcmp(dir, mail_dir) == 0) {
        if ((box->list->props & MAILBOX_LIST_PROP_AUTOCREATE_DIRS) == 0)
            return 0;
        /* the directory might not have been created yet */
    }

    /* we call this function even when the directory exists, so first do a
       quick check to see if we need to mkdir anything */
    if (stat(dir, &st) == 0)
        return 0;

    return mailbox_mkdir(box, dir, type);
}

unsigned int mail_storage_get_lock_timeout(struct mail_storage *storage,
                       unsigned int secs)
{
    return storage->set->mail_max_lock_timeout == 0 ? secs :
        I_MIN(secs, storage->set->mail_max_lock_timeout);
}

enum mail_index_open_flags
mail_storage_settings_to_index_flags(const struct mail_storage_settings *set)
{
    enum mail_index_open_flags index_flags = 0;

#ifndef MMAP_CONFLICTS_WRITE
    if (set->mmap_disable)
#endif
        index_flags |= MAIL_INDEX_OPEN_FLAG_MMAP_DISABLE;
    if (set->dotlock_use_excl)
        index_flags |= MAIL_INDEX_OPEN_FLAG_DOTLOCK_USE_EXCL;
    if (set->mail_nfs_index)
        index_flags |= MAIL_INDEX_OPEN_FLAG_NFS_FLUSH;
    return index_flags;
}

int mail_parse_human_timestamp(const char *str, time_t *timestamp_r)
{
    struct tm tm;
    unsigned int secs;
    const char *error;

    if (i_isdigit(str[0]) && i_isdigit(str[1]) &&
        i_isdigit(str[2]) && i_isdigit(str[3]) && str[4] == '-' &&
        i_isdigit(str[5]) && i_isdigit(str[6]) && str[7] == '-' &&
        i_isdigit(str[8]) && i_isdigit(str[9]) && str[10] == '\0') {
        /* yyyy-mm-dd */
        memset(&tm, 0, sizeof(tm));
        tm.tm_year = (str[0]-'0') * 1000 + (str[1]-'0') * 100 +
            (str[2]-'0') * 10 + (str[3]-'0') - 1900;
        tm.tm_mon = (str[5]-'0') * 10 + (str[6]-'0') - 1;
        tm.tm_mday = (str[8]-'0') * 10 + (str[9]-'0');
        *timestamp_r = mktime(&tm);
        return 0;
    } else if (imap_parse_date(str, timestamp_r)) {
        /* imap date */
        return 0;
    } else if (str_to_time(str, timestamp_r) == 0) {
        /* unix timestamp */
        return 0;
    } else if (settings_get_time(str, &secs, &error) == 0) {
        *timestamp_r = ioloop_time - secs;
        return 0;
    } else {
        return -1;
    }
}