index/maildir/maildir-storage.c

	maildir-storage.c revision 5f5870385cff47efd2f58e7892f251cf13761528
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina/* Copyright (c) 2002-2012 Dovecot authors, see the included COPYING file */
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "lib.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "ioloop.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "mkdir-parents.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "eacces-error.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "unlink-old-files.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "mailbox-uidvalidity.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "mailbox-list-private.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "maildir-storage.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "maildir-uidlist.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "maildir-keywords.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "maildir-sync.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include "index-mail.h"
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#include <sys/stat.h>
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina#define MAILDIR_LIST_CONTEXT(obj) \
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    MODULE_CONTEXT(obj, maildir_mailbox_list_module)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastruct maildir_mailbox_list_context {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    union mailbox_list_module_context module_ctx;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    const struct maildir_settings *set;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina};
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinaextern struct mail_storage maildir_storage;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinaextern struct mailbox maildir_mailbox;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic MODULE_CONTEXT_DEFINE_INIT(maildir_mailbox_list_module,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                  &mailbox_list_module_register);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic const char *maildir_subdirs[] = { "cur", "new", "tmp" };
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic struct mail_storage *maildir_storage_alloc(void)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina{
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    struct maildir_storage *storage;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    pool_t pool;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    pool = pool_alloconly_create("maildir storage", 512+256);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    storage = p_new(pool, struct maildir_storage, 1);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    storage->storage = maildir_storage;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    storage->storage.pool = pool;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    return &storage->storage;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina}
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic int
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinamaildir_storage_create(struct mail_storage *_storage, struct mail_namespace *ns,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina               const char **error_r ATTR_UNUSED)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina{
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    struct maildir_storage *storage = (struct maildir_storage *)_storage;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    struct mailbox_list *list = ns->list;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    const char *dir;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    storage->set = mail_storage_get_driver_settings(_storage);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    storage->temp_prefix = p_strdup(_storage->pool,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                    mailbox_list_get_temp_prefix(list));
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (list->set.control_dir == NULL && list->set.inbox_path == NULL &&
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        (ns->flags & NAMESPACE_FLAG_INBOX_ANY) != 0) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        /* put the temp files into tmp/ directory preferrably */
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        storage->temp_prefix = p_strconcat(_storage->pool, "tmp/",
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                           storage->temp_prefix, NULL);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        dir = mailbox_list_get_path(list, NULL,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                        MAILBOX_LIST_PATH_TYPE_DIR);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    } else {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        /* control dir should also be writable */
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        dir = mailbox_list_get_path(list, NULL,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                        MAILBOX_LIST_PATH_TYPE_CONTROL);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    _storage->temp_path_prefix = p_strconcat(_storage->pool, dir, "/",
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                         storage->temp_prefix, NULL);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    return 0;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina}
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic void maildir_storage_get_list_settings(const struct mail_namespace *ns,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                          struct mailbox_list_settings *set)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina{
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (set->layout == NULL)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        set->layout = MAILBOX_LIST_NAME_MAILDIRPLUSPLUS;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (set->subscription_fname == NULL)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        set->subscription_fname = MAILDIR_SUBSCRIPTION_FILE_NAME;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (set->inbox_path == NULL && *set->maildir_name == '\0' &&
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        (strcmp(set->layout, MAILBOX_LIST_NAME_MAILDIRPLUSPLUS) == 0 ||
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina         strcmp(set->layout, MAILBOX_LIST_NAME_FS) == 0) &&
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        (ns->flags & NAMESPACE_FLAG_INBOX_ANY) != 0) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        /* Maildir++ INBOX is the Maildir base itself */
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        set->inbox_path = set->root_dir;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina}
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic const char *
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinamaildir_storage_find_root_dir(const struct mail_namespace *ns)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina{
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    bool debug = ns->mail_set->mail_debug;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    const char *home, *path;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    /* we'll need to figure out the maildir location ourself.
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina       It's ~/Maildir unless we are chrooted. */
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (mail_user_get_home(ns->owner, &home) > 0) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        path = t_strconcat(home, "/Maildir", NULL);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (access(path, R_OK|W_OK|X_OK) == 0) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                i_debug("maildir: root exists (%s)", path);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            return path;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            i_debug("maildir: access(%s, rwx): failed: %m", path);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    } else {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            i_debug("maildir: Home directory not set");
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (access("/cur", R_OK|W_OK|X_OK) == 0) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                i_debug("maildir: /cur exists, assuming chroot");
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            return "/";
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    return NULL;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina}
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
35fa5a83ce8badf6bc868937047f44c3f32b7c28Sumit Bosestatic bool maildir_storage_autodetect(const struct mail_namespace *ns,
35fa5a83ce8badf6bc868937047f44c3f32b7c28Sumit Bose                       struct mailbox_list_settings *set)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina{
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    bool debug = ns->mail_set->mail_debug;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    struct stat st;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    const char *path, *root_dir;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (set->root_dir != NULL)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        root_dir = set->root_dir;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    else {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        root_dir = maildir_storage_find_root_dir(ns);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (root_dir == NULL) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina                i_debug("maildir: couldn't find root dir");
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            return FALSE;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    path = t_strconcat(root_dir, "/cur", NULL);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (stat(path, &st) < 0) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            i_debug("maildir autodetect: stat(%s) failed: %m", path);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        return FALSE;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (!S_ISDIR(st.st_mode)) {
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        if (debug)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina            i_debug("maildir autodetect: %s not a directory", path);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina        return FALSE;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    }
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    set->root_dir = root_dir;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    maildir_storage_get_list_settings(ns, set);
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    return TRUE;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina}
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinastatic int
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březinamkdir_verify(struct mail_storage *storage, struct mail_namespace *ns,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina         const char *dir, mode_t mode, gid_t gid, const char *gid_origin,
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina         bool verify)
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina{
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    struct stat st;
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina
d3dee2a07f1a8ee9ae6f94e149ced754ef76c248Pavel Březina    if (verify) {
        if (stat(dir, &st) == 0)
            return 0;

        if (errno != ENOENT) {
            mail_storage_set_critical(storage,
                          "stat(%s) failed: %m", dir);
            return -1;
        }
    }

    if (mkdir_parents_chgrp(dir, mode, gid, gid_origin) == 0)
        return 0;

    if (errno == EEXIST) {
        if (verify)
            return 0;
        mail_storage_set_error(storage, MAIL_ERROR_EXISTS,
                       "Mailbox already exists");
    } else if (errno == ENOENT) {
        mail_storage_set_error(storage, MAIL_ERROR_NOTFOUND,
            "Mailbox was deleted while it was being created");
    } else if (errno == EACCES) {
        if (ns->type == NAMESPACE_SHARED) {
            /* shared namespace, don't log permission errors */
            mail_storage_set_error(storage, MAIL_ERROR_PERM,
                           MAIL_ERRSTR_NO_PERMISSION);
            return -1;
        }
        mail_storage_set_critical(storage, "%s",
            mail_error_create_eacces_msg("mkdir", dir));
    } else {
        mail_storage_set_critical(storage,
                      "mkdir(%s) failed: %m", dir);
    }
    return -1;
}

static int maildir_check_tmp(struct mail_storage *storage, const char *dir)
{
    const char *path;
    struct stat st;

    /* if tmp/ directory exists, we need to clean it up once in a while */
    path = t_strconcat(dir, "/tmp", NULL);
    if (stat(path, &st) < 0) {
        if (errno == ENOENT)
            return 0;
        if (errno == EACCES) {
            mail_storage_set_critical(storage, "%s",
                mail_error_eacces_msg("stat", path));
            return -1;
        }
        mail_storage_set_critical(storage, "stat(%s) failed: %m", path);
        return -1;
    }

    if (st.st_atime > st.st_ctime + MAILDIR_TMP_DELETE_SECS) {
        /* the directory should be empty. we won't do anything
           until ctime changes. */
    } else if (st.st_atime < ioloop_time - MAILDIR_TMP_SCAN_SECS) {
        /* time to scan */
        (void)unlink_old_files(path, "",
                       ioloop_time - MAILDIR_TMP_DELETE_SECS);
    }
    return 1;
}

/* create or fix maildir, ignore if it already exists */
static int create_maildir(struct mailbox *box, bool verify)
{
    const struct mailbox_permissions *perm = mailbox_get_permissions(box);
    const char *path;
    unsigned int i;
    enum mail_error error;
    int ret = 0;

    for (i = 0; i < N_ELEMENTS(maildir_subdirs); i++) {
        path = t_strconcat(mailbox_get_path(box), "/",
                   maildir_subdirs[i], NULL);
        if (mkdir_verify(box->storage, box->list->ns, path,
                 perm->dir_create_mode, perm->file_create_gid,
                 perm->file_create_gid_origin, verify) < 0) {
            error = mailbox_get_last_mail_error(box);
            if (error != MAIL_ERROR_EXISTS)
                return -1;
            /* try to create all of the directories in case one
               of them doesn't exist */
            ret = -1;
        }
    }
    return ret;
}

static void maildir_lock_touch_timeout(struct maildir_mailbox *mbox)
{
    (void)maildir_uidlist_lock_touch(mbox->uidlist);
}

static struct mailbox *
maildir_mailbox_alloc(struct mail_storage *storage, struct mailbox_list *list,
              const char *vname, enum mailbox_flags flags)
{
    struct maildir_mailbox *mbox;
    pool_t pool;

    pool = pool_alloconly_create("maildir mailbox", 1024*3);
    mbox = p_new(pool, struct maildir_mailbox, 1);
    mbox->box = maildir_mailbox;
    mbox->box.pool = pool;
    mbox->box.storage = storage;
    mbox->box.list = list;
    mbox->box.mail_vfuncs = &maildir_mail_vfuncs;
    mbox->maildir_list_index_ext_id = (uint32_t)-1;

    index_storage_mailbox_alloc(&mbox->box, vname, flags,
                    MAILDIR_INDEX_PREFIX);

    mbox->storage = (struct maildir_storage *)storage;
    return &mbox->box;
}

static int maildir_mailbox_open_existing(struct mailbox *box)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;

    mbox->uidlist = maildir_uidlist_init(mbox);
    mbox->keywords = maildir_keywords_init(mbox);

    if ((box->flags & MAILBOX_FLAG_KEEP_LOCKED) != 0) {
        if (maildir_uidlist_lock(mbox->uidlist) <= 0)
            return -1;
        mbox->keep_lock_to = timeout_add(MAILDIR_LOCK_TOUCH_SECS * 1000,
                         maildir_lock_touch_timeout,
                         mbox);
    }

    if (index_storage_mailbox_open(box, FALSE) < 0)
        return -1;

    mbox->maildir_ext_id =
        mail_index_ext_register(mbox->box.index, "maildir",
                    sizeof(mbox->maildir_hdr), 0, 0);
    return 0;
}

static bool maildir_storage_is_readonly(struct mailbox *box)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;

    if (index_storage_is_readonly(box))
        return TRUE;

    if (maildir_is_backend_readonly(mbox)) {
        /* return read-only only if there are no private flags
           (that are stored in index files) */
        if (mailbox_get_private_flags_mask(box) == 0)
            return TRUE;
    }
    return FALSE;
}

static int
maildir_mailbox_exists(struct mailbox *box, bool auto_boxes ATTR_UNUSED,
               enum mailbox_existence *existence_r)
{
    return index_storage_mailbox_exists_full(box, "cur", existence_r);
}

static int maildir_mailbox_open(struct mailbox *box)
{
    const char *box_path = mailbox_get_path(box);
    const char *root_dir;
    struct stat st;
    int ret;

    /* begin by checking if tmp/ directory exists and if it should be
       cleaned up. */
    ret = maildir_check_tmp(box->storage, box_path);
    if (ret > 0) {
        /* exists */
        return maildir_mailbox_open_existing(box);
    }
    if (ret < 0)
        return -1;

    /* tmp/ directory doesn't exist. does the maildir? */
    root_dir = mailbox_list_get_path(box->list, NULL,
                     MAILBOX_LIST_PATH_TYPE_MAILBOX);
    if (strcmp(box_path, root_dir) == 0) {
        /* root directory. either INBOX or some other namespace root */
        errno = ENOENT;
    } else if (stat(box_path, &st) == 0) {
        /* yes, we'll need to create the missing dirs */
        if (create_maildir(box, TRUE) < 0)
            return -1;

        return maildir_mailbox_open_existing(box);
    }

    if (errno == ENOENT) {
        mail_storage_set_error(box->storage, MAIL_ERROR_NOTFOUND,
            T_MAIL_ERR_MAILBOX_NOT_FOUND(box->name));
        return -1;
    } else {
        mail_storage_set_critical(box->storage,
                      "stat(%s) failed: %m", box_path);
        return -1;
    }
}

static int maildir_create_shared(struct mailbox *box)
{
    const struct mailbox_permissions *perm = mailbox_get_permissions(box);
    const char *path;
    mode_t old_mask;
    int fd;

    old_mask = umask(0);
    path = t_strconcat(mailbox_get_path(box), "/dovecot-shared", NULL);
    fd = open(path, O_WRONLY | O_CREAT, perm->file_create_mode);
    umask(old_mask);

    if (fd == -1) {
        mail_storage_set_critical(box->storage, "open(%s) failed: %m",
                      path);
        return -1;
    }

    if (fchown(fd, (uid_t)-1, perm->file_create_gid) < 0) {
        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);
        }
    }
    (void)close(fd);
    return 0;
}

static int
maildir_mailbox_update(struct mailbox *box, const struct mailbox_update *update)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;
    struct maildir_uidlist *uidlist;
    int ret;

    if (!box->opened) {
        if (mailbox_open(box) < 0)
            return -1;
    }
    uidlist = mbox->uidlist;

    if (maildir_uidlist_lock(uidlist) <= 0)
        return -1;

    if (!guid_128_is_empty(update->mailbox_guid))
        maildir_uidlist_set_mailbox_guid(uidlist, update->mailbox_guid);
    if (update->uid_validity != 0)
        maildir_uidlist_set_uid_validity(uidlist, update->uid_validity);
    if (update->min_next_uid != 0) {
        maildir_uidlist_set_next_uid(uidlist, update->min_next_uid,
                         FALSE);
    }
    ret = maildir_uidlist_update(uidlist);
    if (ret == 0)
        ret = index_storage_mailbox_update(box, update);
    maildir_uidlist_unlock(uidlist);
    return ret;
}

static int
maildir_mailbox_create(struct mailbox *box, const struct mailbox_update *update,
               bool directory)
{
    const char *root_dir, *shared_path;
    struct stat st;
    int ret;

    if (directory &&
        (box->list->props & MAILBOX_LIST_PROP_NO_NOSELECT) == 0)
        return 0;

    ret = maildir_check_tmp(box->storage, mailbox_get_path(box));
    if (ret > 0) {
        mail_storage_set_error(box->storage, MAIL_ERROR_EXISTS,
                       "Mailbox already exists");
        return -1;
    }
    if (ret < 0)
        return -1;

    if (create_maildir(box, FALSE) < 0)
        return -1;

    /* if dovecot-shared exists in the root dir, copy it to newly
       created mailboxes */
    root_dir = mailbox_list_get_path(box->list, NULL,
                     MAILBOX_LIST_PATH_TYPE_MAILBOX);
    shared_path = t_strconcat(root_dir, "/dovecot-shared", NULL);
    if (stat(shared_path, &st) == 0) {
        if (maildir_create_shared(box) < 0)
            return -1;
    }

    return update == NULL ? 0 : maildir_mailbox_update(box, update);
}

static int
maildir_mailbox_get_metadata(struct mailbox *box,
                 enum mailbox_metadata_items items,
                 struct mailbox_metadata *metadata_r)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;

    if (index_mailbox_get_metadata(box, items, metadata_r) < 0)
        return -1;

    if ((items & MAILBOX_METADATA_GUID) != 0) {
        if (maildir_uidlist_get_mailbox_guid(mbox->uidlist,
                             metadata_r->guid) < 0)
            return -1;
    }
    return 0;
}

static void maildir_mailbox_close(struct mailbox *box)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;

    if (mbox->keep_lock_to != NULL) {
        maildir_uidlist_unlock(mbox->uidlist);
        timeout_remove(&mbox->keep_lock_to);
    }

    if (mbox->flags_view != NULL)
        mail_index_view_close(&mbox->flags_view);
    if (mbox->keywords != NULL)
        maildir_keywords_deinit(&mbox->keywords);
    maildir_uidlist_deinit(&mbox->uidlist);
    index_storage_mailbox_close(box);
}

static void maildir_notify_changes(struct mailbox *box)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;
    const char *box_path = mailbox_get_path(box);

    if (box->notify_callback == NULL)
        index_mailbox_check_remove_all(&mbox->box);
    else {
        index_mailbox_check_add(&mbox->box,
            t_strconcat(box_path, "/new", NULL));
        index_mailbox_check_add(&mbox->box,
            t_strconcat(box_path, "/cur", NULL));
    }
}

static bool
maildir_is_internal_name(struct mailbox_list *list ATTR_UNUSED,
             const char *name)
{
    return strcmp(name, "cur") == 0 ||
        strcmp(name, "new") == 0 ||
        strcmp(name, "tmp") == 0;
}

static void maildir_storage_add_list(struct mail_storage *storage,
                     struct mailbox_list *list)
{
    struct maildir_mailbox_list_context *mlist;

    mlist = p_new(list->pool, struct maildir_mailbox_list_context, 1);
    mlist->module_ctx.super = list->v;
    mlist->set = mail_storage_get_driver_settings(storage);

    list->v.is_internal_name = maildir_is_internal_name;
    MODULE_CONTEXT_SET(list, maildir_mailbox_list_module, mlist);
}

uint32_t maildir_get_uidvalidity_next(struct mailbox_list *list)
{
    const char *path;

    path = mailbox_list_get_path(list, NULL,
                     MAILBOX_LIST_PATH_TYPE_CONTROL);
    path = t_strconcat(path, "/"MAILDIR_UIDVALIDITY_FNAME, NULL);
    return mailbox_uidvalidity_next(list, path);
}

static enum mail_flags maildir_get_private_flags_mask(struct mailbox *box)
{
    struct maildir_mailbox *mbox = (struct maildir_mailbox *)box;
    const char *path, *path2;
    struct stat st;

    if (mbox->private_flags_mask_set)
        return mbox->_private_flags_mask;
    mbox->private_flags_mask_set = TRUE;

    path = mailbox_list_get_path(box->list, NULL,
                     MAILBOX_LIST_PATH_TYPE_MAILBOX);
    path2 = mailbox_list_get_path(box->list, NULL,
                      MAILBOX_LIST_PATH_TYPE_INDEX);
    if (strcmp(path, path2) == 0) {
        /* no separate index directory. we can't have private flags,
           so don't even bother checking if dovecot-shared exists */
    } else {
        path = t_strconcat(mailbox_get_path(box),
                   "/dovecot-shared", NULL);
        if (stat(path, &st) == 0)
            mbox->_private_flags_mask = MAIL_SEEN;
    }
    return mbox->_private_flags_mask;
}

bool maildir_is_backend_readonly(struct maildir_mailbox *mbox)
{
    if (!mbox->backend_readonly_set) {
        const char *box_path = mailbox_get_path(&mbox->box);

        mbox->backend_readonly_set = TRUE;
        if (access(t_strconcat(box_path, "/cur", NULL), W_OK) < 0 &&
            errno == EACCES)
            mbox->backend_readonly = TRUE;
    }
    return mbox->backend_readonly;
}

struct mail_storage maildir_storage = {
    .name = MAILDIR_STORAGE_NAME,
    .class_flags = MAIL_STORAGE_CLASS_FLAG_FILE_PER_MSG,

    .v = {
                maildir_get_setting_parser_info,
        maildir_storage_alloc,
        maildir_storage_create,
        NULL,
        maildir_storage_add_list,
        maildir_storage_get_list_settings,
        maildir_storage_autodetect,
        maildir_mailbox_alloc,
        NULL
    }
};

struct mailbox maildir_mailbox = {
    .v = {
        maildir_storage_is_readonly,
        index_storage_mailbox_enable,
        maildir_mailbox_exists,
        maildir_mailbox_open,
        maildir_mailbox_close,
        index_storage_mailbox_free,
        maildir_mailbox_create,
        maildir_mailbox_update,
        index_storage_mailbox_delete,
        index_storage_mailbox_rename,
        index_storage_get_status,
        maildir_mailbox_get_metadata,
        index_storage_set_subscribed,
        maildir_list_index_has_changed,
        maildir_list_index_update_sync,
        maildir_storage_sync_init,
        index_mailbox_sync_next,
        index_mailbox_sync_deinit,
        NULL,
        maildir_notify_changes,
        index_transaction_begin,
        index_transaction_commit,
        index_transaction_rollback,
        maildir_get_private_flags_mask,
        index_mail_alloc,
        index_storage_search_init,
        index_storage_search_deinit,
        index_storage_search_next_nonblock,
        index_storage_search_next_update_seq,
        maildir_save_alloc,
        maildir_save_begin,
        maildir_save_continue,
        maildir_save_finish,
        maildir_save_cancel,
        maildir_copy,
        maildir_transaction_save_commit_pre,
        maildir_transaction_save_commit_post,
        maildir_transaction_save_rollback,
        index_storage_is_inconsistent
    }
};