index/shared/shared-storage.c

/* Copyright (c) 2008-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "array.h"
#include "str.h"
#include "ioloop.h"
#include "var-expand.h"
#include "index-storage.h"
#include "mail-storage-service.h"
#include "mailbox-list-private.h"
#include "fail-mail-storage.h"
#include "shared-storage.h"

#include <ctype.h>

extern struct mail_storage shared_storage;

static struct mail_storage *shared_storage_alloc(void)
{
    struct shared_storage *storage;
    pool_t pool;

    pool = pool_alloconly_create("shared storage", 1024);
    storage = p_new(pool, struct shared_storage, 1);
    storage->storage = shared_storage;
    storage->storage.pool = pool;
    return &storage->storage;
}

static int
shared_storage_create(struct mail_storage *_storage, struct mail_namespace *ns,
              const char **error_r)
{
    struct shared_storage *storage = SHARED_STORAGE(_storage);
    const char *driver, *p;
    char *wildcardp, key;
    bool have_username;

    /* location must begin with the actual mailbox driver */
    p = strchr(ns->set->location, ':');
    if (p == NULL) {
        *error_r = "Shared mailbox location not prefixed with driver";
        return -1;
    }
    driver = t_strdup_until(ns->set->location, p);
    storage->location = p_strdup(_storage->pool, ns->set->location);
    storage->unexpanded_location =
        p_strdup(_storage->pool, ns->unexpanded_set->location);
    storage->storage_class_name = p_strdup(_storage->pool, driver);

    if (mail_user_get_storage_class(_storage->user, driver) == NULL &&
        strcmp(driver, "auto") != 0) {
        *error_r = t_strconcat("Unknown shared storage driver: ",
                       driver, NULL);
        return -1;
    }

    wildcardp = strchr(ns->prefix, '%');
    if (wildcardp == NULL) {
        *error_r = "Shared namespace prefix doesn't contain %";
        return -1;
    }
    storage->ns_prefix_pattern = p_strdup(_storage->pool, wildcardp);

    have_username = FALSE;
    for (p = storage->ns_prefix_pattern; *p != '\0'; p++) {
        if (*p != '%')
            continue;

        key = p[1];
        if (key == 'u' || key == 'n')
            have_username = TRUE;
        else if (key != '%' && key != 'd')
            break;
    }
    if (*p != '\0') {
        *error_r = "Shared namespace prefix contains unknown variables";
        return -1;
    }
    if (!have_username) {
        *error_r = "Shared namespace prefix doesn't contain %u or %n";
        return -1;
    }
    if (p[-1] != mail_namespace_get_sep(ns) &&
        (ns->flags & (NAMESPACE_FLAG_LIST_PREFIX |
              NAMESPACE_FLAG_LIST_CHILDREN)) != 0) {
        *error_r = "Shared namespace prefix doesn't end with hierarchy separator";
        return -1;
    }

    /* truncate prefix after the above checks are done, so they can log
       the full prefix in error conditions */
    *wildcardp = '\0';
    ns->prefix_len = strlen(ns->prefix);
    return 0;
}

static void
shared_storage_get_list_settings(const struct mail_namespace *ns ATTR_UNUSED,
                 struct mailbox_list_settings *set)
{
    set->layout = "shared";
}

static void
get_nonexistent_user_location(struct shared_storage *storage,
                  const char *username, string_t *location)
{
    /* user wasn't found. we'll still need to create the storage
       to avoid exposing which users exist and which don't. */
    str_append(location, storage->storage_class_name);
    str_append_c(location, ':');

    /* use a reachable but nonexistent path as the mail root directory */
    str_append(location, storage->storage.user->set->base_dir);
    str_append(location, "/user-not-found/");
    str_append(location, username);
}

static bool shared_namespace_exists(struct mail_namespace *ns)
{
    const char *path;
    struct stat st;

    path = mailbox_list_get_root_forced(ns->list, MAILBOX_LIST_PATH_TYPE_DIR);
    if (path == NULL) {
        /* we can't know if this exists */
        return TRUE;
    }
    return stat(path, &st) == 0;
}

int shared_storage_get_namespace(struct mail_namespace **_ns,
                 const char **_name)
{
    struct mail_storage *_storage = (*_ns)->storage;
    struct mailbox_list *list = (*_ns)->list;
    struct shared_storage *storage = SHARED_STORAGE(_storage);
    struct mail_user *user = _storage->user;
    struct mail_namespace *new_ns, *ns = *_ns;
    struct mail_namespace_settings *ns_set, *unexpanded_ns_set;
    struct mail_user *owner;
    const char *domain = NULL, *username = NULL, *userdomain = NULL;
    const char *name, *p, *next, **dest, *error;
    string_t *prefix, *location;
    char ns_sep = mail_namespace_get_sep(ns);
    int ret;

    p = storage->ns_prefix_pattern;
    for (name = *_name; *p != '\0';) {
        if (*p != '%') {
            if (*p != *name)
                break;
            p++; name++;
            continue;
        }
        switch (*++p) {
        case 'd':
            dest = &domain;
            break;
        case 'n':
            dest = &username;
            break;
        case 'u':
            dest = &userdomain;
            break;
        default:
            /* we checked this already above */
            i_unreached();
        }
        p++;

        next = strchr(name, *p != '\0' ? *p : ns_sep);
        if (next == NULL) {
            *dest = name;
            name = "";
            break;
        }
        *dest = t_strdup_until(name, next);
        name = next;
    }
    if (*p != '\0') {
        if (*name == '\0' ||
            (name[1] == '\0' && *name == ns_sep)) {
            /* trying to open <prefix>/<user> mailbox */
            name = "INBOX";
        } else {
            mailbox_list_set_critical(list,
                    "Invalid namespace prefix %s vs %s",
                    storage->ns_prefix_pattern, *_name);
            return -1;
        }
    }

    /* successfully matched the name. */
    if (userdomain != NULL) {
        /* user@domain given */
        domain = strchr(userdomain, '@');
        if (domain == NULL)
            username = userdomain;
        else {
            username = t_strdup_until(userdomain, domain);
            domain++;
        }
    } else if (username == NULL) {
        /* trying to open namespace "shared/domain"
           namespace prefix. */
        mailbox_list_set_error(list, MAIL_ERROR_NOTFOUND,
                       T_MAIL_ERR_MAILBOX_NOT_FOUND(*_name));
        return -1;
    } else {
        if (domain == NULL) {
            /* no domain given, use ours (if we have one) */
            domain = i_strchr_to_next(user->username, '@');
        }
        userdomain = domain == NULL ? username :
            t_strconcat(username, "@", domain, NULL);
    }
    if (*userdomain == '\0') {
        mailbox_list_set_error(list, MAIL_ERROR_PARAMS,
                       "Empty username doesn't exist");
        return -1;
    }

    /* expand the namespace prefix and see if it already exists.
       this should normally happen only when the mailbox is being opened */
    struct var_expand_table tab[] = {
        { 'u', userdomain, "user" },
        { 'n', username, "username" },
        { 'd', domain, "domain" },
        { 'h', NULL, "home" },
        { '\0', NULL, NULL }
    };

    prefix = t_str_new(128);
    str_append(prefix, ns->prefix);
    if (var_expand(prefix, storage->ns_prefix_pattern, tab, &error) <= 0) {
        mailbox_list_set_critical(list,
            "Failed to expand namespace prefix '%s': %s",
            storage->ns_prefix_pattern, error);
        return -1;
    }

    *_ns = mail_namespace_find_prefix(user->namespaces, str_c(prefix));
    if (*_ns != NULL) {
        *_name = mailbox_list_get_storage_name(ns->list,
                t_strconcat(ns->prefix, name, NULL));
        return 0;
    }

    owner = mail_user_alloc(event_get_parent(user->event), userdomain,
                user->set_info, user->unexpanded_set);
    owner->_service_user = user->_service_user;
    mail_storage_service_user_ref(owner->_service_user);
    owner->creator = user;
    owner->autocreated = TRUE;
    owner->session_id = p_strdup(owner->pool, user->session_id);
    if (mail_user_init(owner, &error) < 0) {
        if (!owner->nonexistent) {
            mailbox_list_set_critical(list,
                "Couldn't create namespace '%s' for user %s: %s",
                ns->prefix, userdomain, error);
            mail_user_unref(&owner);
            return -1;
        }
        ret = 0;
    } else if (!var_has_key(storage->location, 'h', "home")) {
        ret = 1;
    } else {
        /* we'll need to look up the user's home directory */
        if ((ret = mail_user_get_home(owner, &tab[3].value)) < 0) {
            mailbox_list_set_critical(list, "Namespace '%s': "
                "Could not lookup home for user %s",
                ns->prefix, userdomain);
            mail_user_unref(&owner);
            return -1;
        }
    }

    location = t_str_new(256);
    if (ret > 0 &&
        var_expand(location, storage->location, tab, &error) <= 0) {
        mailbox_list_set_critical(list,
            "Failed to expand namespace location '%s': %s",
            storage->location, error);
        return -1;
    }

    /* create the new namespace */
    new_ns = i_new(struct mail_namespace, 1);
    new_ns->refcount = 1;
    new_ns->type = MAIL_NAMESPACE_TYPE_SHARED;
    new_ns->user = user;
    new_ns->prefix = i_strdup(str_c(prefix));
    new_ns->owner = owner;
    new_ns->flags = (NAMESPACE_FLAG_SUBSCRIPTIONS & ns->flags) |
        NAMESPACE_FLAG_LIST_PREFIX | NAMESPACE_FLAG_HIDDEN |
        NAMESPACE_FLAG_AUTOCREATED | NAMESPACE_FLAG_INBOX_ANY;
    new_ns->user_set = user->set;
    new_ns->mail_set = _storage->set;
    i_array_init(&new_ns->all_storages, 2);

    if (ret <= 0) {
        get_nonexistent_user_location(storage, userdomain, location);
        new_ns->flags |= NAMESPACE_FLAG_UNUSABLE;
        if (ns->user->mail_debug) {
            i_debug("shared: Tried to access mails of "
                "nonexistent user %s", userdomain);
        }
    }

    ns_set = p_new(user->pool, struct mail_namespace_settings, 1);
    ns_set->type = "shared";
    ns_set->separator = p_strdup_printf(user->pool, "%c", ns_sep);
    ns_set->prefix = new_ns->prefix;
    ns_set->location = p_strdup(user->pool, str_c(location));
    ns_set->hidden = TRUE;
    ns_set->list = "yes";
    new_ns->set = ns_set;

    unexpanded_ns_set =
        p_new(user->pool, struct mail_namespace_settings, 1);
    *unexpanded_ns_set = *ns_set;
    unexpanded_ns_set->location =
        p_strdup(user->pool, storage->unexpanded_location);
    new_ns->unexpanded_set = unexpanded_ns_set;

    /* We need to create a prefix="" namespace for the owner */
    if (mail_namespaces_init_location(owner, str_c(location), &error) < 0) {
        /* owner gets freed by namespace deinit */
        mail_namespace_destroy(new_ns);
        return -1;
    }

    if (mail_storage_create(new_ns, NULL, _storage->flags |
                MAIL_STORAGE_FLAG_NO_AUTOVERIFY, &error) < 0) {
        mailbox_list_set_critical(list, "Namespace '%s': %s",
                      new_ns->prefix, error);
        /* owner gets freed by namespace deinit */
        mail_namespace_destroy(new_ns);
        return -1;
    }
    if ((new_ns->flags & NAMESPACE_FLAG_UNUSABLE) == 0 &&
        !shared_namespace_exists(new_ns)) {
        /* this user doesn't have a usable storage */
        new_ns->flags |= NAMESPACE_FLAG_UNUSABLE;
    }
    /* mark the shared namespace root as usable, since it now has
       child namespaces */
    ns->flags |= NAMESPACE_FLAG_USABLE;
    *_name = mailbox_list_get_storage_name(new_ns->list,
                t_strconcat(new_ns->prefix, name, NULL));
    *_ns = new_ns;
    if (_storage->class_flags == 0) {
        /* flags are unset if we were using "auto" storage */
        _storage->class_flags =
            mail_namespace_get_default_storage(new_ns)->class_flags;
    }

    mail_user_add_namespace(user, &new_ns);
    return 0;
}

struct mail_storage shared_storage = {
    .name = MAIL_SHARED_STORAGE_NAME,
    .class_flags = 0, /* unknown at this point */

    .v = {
        NULL,
        shared_storage_alloc,
        shared_storage_create,
        index_storage_destroy,
        NULL,
        shared_storage_get_list_settings,
        NULL,
        fail_mailbox_alloc,
        NULL,
        NULL,
    }
};