src/imap/imap-notify.c

/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */

#include "imap-common.h"
#include "str.h"
#include "ostream.h"
#include "imap-quote.h"
#include "mailbox-list-iter.h"
#include "mailbox-list-notify.h"
#include "mail-search.h"
#include "mail-search-build.h"
#include "imap-commands.h"
#include "imap-fetch.h"
#include "imap-list.h"
#include "imap-status.h"
#include "imap-notify.h"

#define IMAP_NOTIFY_WATCH_ADD_DELAY_MSECS 1000

static int imap_notify_list(struct imap_notify_namespace *notify_ns,
                const struct mailbox_list_notify_rec *rec,
                enum mailbox_info_flags flags)
{
    string_t *str = t_str_new(128);
    char ns_sep = mail_namespace_get_sep(notify_ns->ns);

    str_append(str, "* LIST (");
    imap_mailbox_flags2str(str, flags);
    str_append(str, ") \"");
    if (ns_sep == '\\')
        str_append_c(str, '\\');
    str_append_c(str, ns_sep);
    str_append(str, "\" ");

    imap_append_astring(str, rec->vname);
    if (rec->old_vname != NULL) {
        str_append(str, " (\"OLDNAME\" (");
        imap_append_astring(str, rec->old_vname);
        str_append(str, "))");
    }
    return client_send_line_next(notify_ns->ctx->client, str_c(str));
}

static int imap_notify_status(struct imap_notify_namespace *notify_ns,
                  const struct mailbox_list_notify_rec *rec)
{
    struct client *client = notify_ns->ctx->client;
    struct mailbox *box;
    struct imap_status_items items;
    struct imap_status_result result;
    enum mail_error error;
    int ret = 1;

    i_zero(&items);
    if ((client->enabled_features & MAILBOX_FEATURE_CONDSTORE) != 0)
        items.status |= STATUS_HIGHESTMODSEQ;

    box = mailbox_alloc(notify_ns->ns->list, rec->vname, 0);
    mailbox_set_reason(box, "NOTIFY STATUS");
    if ((rec->events & MAILBOX_LIST_NOTIFY_UIDVALIDITY) != 0) {
        items.status |= STATUS_UIDVALIDITY | STATUS_UIDNEXT |
            STATUS_MESSAGES | STATUS_UNSEEN;
    }
    if ((rec->events & (MAILBOX_LIST_NOTIFY_APPENDS |
                MAILBOX_LIST_NOTIFY_EXPUNGES)) != 0)
        items.status |= STATUS_UIDNEXT | STATUS_MESSAGES | STATUS_UNSEEN;
    if ((rec->events & MAILBOX_LIST_NOTIFY_SEEN_CHANGES) != 0)
        items.status |= STATUS_UNSEEN;
    if ((rec->events & MAILBOX_LIST_NOTIFY_MODSEQ_CHANGES) != 0) {
        /* if HIGHESTMODSEQ isn't being sent, don't send anything */
    }
    if (items.status == 0) {
        /* don't send anything */
    } else if (mailbox_get_status(box, items.status, &result.status) < 0) {
        /* hide permission errors from client. we don't want to leak
           information about existence of mailboxes where user doesn't
           have access to */
        (void)mailbox_get_last_error(box, &error);
        if (error != MAIL_ERROR_PERM)
            ret = -1;
    } else {
        ret = imap_status_send(client, rec->vname, &items, &result);
    }
    mailbox_free(&box);
    return ret;
}

static int
imap_notify_next(struct imap_notify_namespace *notify_ns,
         const struct mailbox_list_notify_rec *rec)
{
    enum mailbox_info_flags mailbox_flags;
    int ret;

    if ((rec->events & MAILBOX_LIST_NOTIFY_CREATE) != 0) {
        if (mailbox_list_mailbox(notify_ns->ns->list, rec->storage_name,
                     &mailbox_flags) < 0)
            mailbox_flags = 0;
        if ((ret = imap_notify_list(notify_ns, rec, mailbox_flags)) <= 0)
            return ret;
    }
    if ((rec->events & MAILBOX_LIST_NOTIFY_DELETE) != 0) {
        if ((ret = imap_notify_list(notify_ns, rec, MAILBOX_NONEXISTENT)) < 0)
            return ret;
    }
    if ((rec->events & MAILBOX_LIST_NOTIFY_RENAME) != 0) {
        if (mailbox_list_mailbox(notify_ns->ns->list, rec->storage_name,
                     &mailbox_flags) < 0)
            mailbox_flags = 0;
        if ((ret = imap_notify_list(notify_ns, rec, mailbox_flags)) < 0)
            return ret;
    }
    if ((rec->events & MAILBOX_LIST_NOTIFY_SUBSCRIBE) != 0) {
        if (mailbox_list_mailbox(notify_ns->ns->list, rec->storage_name,
                     &mailbox_flags) < 0)
            mailbox_flags = 0;
        if ((ret = imap_notify_list(notify_ns, rec,
                     mailbox_flags | MAILBOX_SUBSCRIBED)) < 0)
            return ret;
    }
    if ((rec->events & MAILBOX_LIST_NOTIFY_UNSUBSCRIBE) != 0) {
        if (mailbox_list_mailbox(notify_ns->ns->list, rec->storage_name,
                     &mailbox_flags) < 0)
            mailbox_flags = 0;
        if ((ret = imap_notify_list(notify_ns, rec, mailbox_flags)) < 0)
            return ret;
    }
    if ((rec->events & (MAILBOX_LIST_NOTIFY_UIDVALIDITY |
                MAILBOX_LIST_NOTIFY_APPENDS |
                MAILBOX_LIST_NOTIFY_EXPUNGES |
                MAILBOX_LIST_NOTIFY_SEEN_CHANGES |
                MAILBOX_LIST_NOTIFY_MODSEQ_CHANGES)) != 0) {
        if ((ret = imap_notify_status(notify_ns, rec)) < 0)
            return ret;
    }
    return 1;
}

static bool
imap_notify_match_event(struct imap_notify_namespace *notify_ns,
            const struct imap_notify_mailboxes *notify_boxes,
            const struct mailbox_list_notify_rec *rec)
{
    enum imap_notify_event wanted_events = notify_boxes->events;
    struct mailbox *box;

    /* check for mailbox list events first */
    if ((wanted_events & IMAP_NOTIFY_EVENT_MAILBOX_NAME) != 0) {
        if ((rec->events & (MAILBOX_LIST_NOTIFY_CREATE |
                    MAILBOX_LIST_NOTIFY_DELETE |
                    MAILBOX_LIST_NOTIFY_RENAME)) != 0)
            return TRUE;
    }
    if ((wanted_events & IMAP_NOTIFY_EVENT_SUBSCRIPTION_CHANGE) != 0) {
        if ((rec->events & (MAILBOX_LIST_NOTIFY_SUBSCRIBE |
                    MAILBOX_LIST_NOTIFY_UNSUBSCRIBE)) != 0)
            return TRUE;
    }

    /* if this is an event for the selected mailbox, ignore it */
    box = notify_ns->ctx->client->mailbox;
    if (box != NULL && mailbox_equals(box, notify_ns->ns, rec->vname))
        return FALSE;

    if ((wanted_events & (IMAP_NOTIFY_EVENT_MESSAGE_NEW |
                  IMAP_NOTIFY_EVENT_MESSAGE_EXPUNGE |
                  IMAP_NOTIFY_EVENT_FLAG_CHANGE)) != 0) {
        if ((rec->events & MAILBOX_LIST_NOTIFY_UIDVALIDITY) != 0)
            return TRUE;
    }
    if ((wanted_events & IMAP_NOTIFY_EVENT_MESSAGE_NEW) != 0) {
        if ((rec->events & MAILBOX_LIST_NOTIFY_APPENDS) != 0)
            return TRUE;
    }
    if ((wanted_events & IMAP_NOTIFY_EVENT_MESSAGE_EXPUNGE) != 0) {
        if ((rec->events & MAILBOX_LIST_NOTIFY_EXPUNGES) != 0)
            return TRUE;
    }
    if ((wanted_events & IMAP_NOTIFY_EVENT_FLAG_CHANGE) != 0) {
        if ((rec->events & (MAILBOX_LIST_NOTIFY_SEEN_CHANGES |
                    MAILBOX_LIST_NOTIFY_MODSEQ_CHANGES)) != 0)
            return TRUE;
    }
    return FALSE;
}

bool imap_notify_match_mailbox(struct imap_notify_namespace *notify_ns,
                   const struct imap_notify_mailboxes *notify_boxes,
                   const char *vname)
{
    struct mailbox *box;
    const char *const *namep;
    size_t name_len;
    char ns_sep;
    bool ret;

    switch (notify_boxes->type) {
    case IMAP_NOTIFY_TYPE_SUBSCRIBED:
        box = mailbox_alloc(notify_ns->ns->list, vname, 0);
        mailbox_set_reason(box, "NOTIFY is subscribed");
        ret = mailbox_is_subscribed(box);
        mailbox_free(&box);
        return ret;
    case IMAP_NOTIFY_TYPE_SUBTREE:
        ns_sep = mail_namespace_get_sep(notify_ns->ns);
        array_foreach(&notify_boxes->names, namep) {
            name_len = strlen(*namep);
            if (name_len == 0) {
                /* everything under root. NOTIFY spec itself
                   doesn't define this, but we use it for
                   implementing "personal" */
                return TRUE;
            }
            if (strncmp(*namep, vname, name_len) == 0 &&
                (vname[name_len] == '\0' ||
                 vname[name_len] == ns_sep))
                return TRUE;
        }
        break;
    case IMAP_NOTIFY_TYPE_MAILBOX:
        array_foreach(&notify_boxes->names, namep) {
            if (strcmp(*namep, vname) == 0)
                return TRUE;
        }
        break;
    }
    return FALSE;
}

static bool
imap_notify_match(struct imap_notify_namespace *notify_ns,
          const struct mailbox_list_notify_rec *rec)
{
    const struct imap_notify_mailboxes *notify_boxes;

    array_foreach(&notify_ns->mailboxes, notify_boxes) {
        if (imap_notify_match_event(notify_ns, notify_boxes, rec) &&
            imap_notify_match_mailbox(notify_ns, notify_boxes, rec->vname))
            return TRUE;
    }
    return FALSE;
}

static int imap_client_notify_ns(struct imap_notify_namespace *notify_ns)
{
    const struct mailbox_list_notify_rec *rec;
    int ret, ret2 = 1;

    if (notify_ns->notify == NULL)
        return 0; /* notifications not supported in this namespace */

    while ((ret = mailbox_list_notify_next(notify_ns->notify, &rec)) > 0) {
        if (imap_notify_match(notify_ns, rec)) T_BEGIN {
            ret2 = imap_notify_next(notify_ns, rec);
        } T_END;
        if (ret2 <= 0)
            break;
    }
    if (ret < 0) {
        /* failed to get some notifications */
        return -1;
    }
    return ret2;
}

static int
imap_client_notify_selected(struct client *client)
{
    struct imap_fetch_context *fetch_ctx = client->notify_ctx->fetch_ctx;
    int ret;

    if (!fetch_ctx->state.fetching)
        return 1;

    if ((ret = imap_fetch_more_no_lock_update(fetch_ctx)) <= 0)
        return ret;
    /* finished the FETCH */
    if (imap_fetch_end(fetch_ctx) < 0)
        return -1;
    return 1;
}

static int imap_client_notify_more(struct client *client)
{
    struct imap_notify_namespace *notify_ns;
    int ret = 1;

    /* send notifications for selected mailbox first. note that it may
       leave the client's output stream in the middle of a FETCH reply. */
    if (client->notify_ctx->fetch_ctx != NULL) {
        if ((ret = imap_client_notify_selected(client)) < 0) {
            client->notify_ctx->fetch_ctx->state.failed = FALSE;
            ret = -1;
        }
    }

    /* send notifications for non-selected mailboxes */
    array_foreach_modifiable(&client->notify_ctx->namespaces, notify_ns) {
        if (ret == 0)
            break;
        if (imap_client_notify_ns(notify_ns) < 0)
            ret = -1;
    }

    if (ret < 0) {
        client_send_line(notify_ns->ctx->client,
            "* NO NOTIFY error, some events may have got lost");
    }
    return ret;
}

int imap_client_notify_newmails(struct client *client)
{
    struct imap_fetch_context *fetch_ctx = client->notify_ctx->fetch_ctx;
    struct mailbox_status status;
    struct mail_search_args *search_args;
    struct mail_search_arg *arg;

    i_assert(client->mailbox != NULL);

    if (fetch_ctx == NULL) {
        /* FETCH notifications not enabled in this session */
        return 1;
    }
    if (client->notify_ctx->notifying)
        return imap_client_notify_more(client);
    client->notify_ctx->notifying = TRUE;

    i_assert(!fetch_ctx->state.fetching);

    mailbox_get_open_status(client->mailbox, STATUS_UIDNEXT, &status);

    search_args = mail_search_build_init();
    arg = mail_search_build_add(search_args, SEARCH_UIDSET);
    p_array_init(&arg->value.seqset, search_args->pool, 1);
    seq_range_array_add_range(&arg->value.seqset,
                  client->notify_uidnext, status.uidnext-1);
    client->notify_uidnext = status.uidnext;

    imap_fetch_begin(fetch_ctx, client->mailbox, search_args);
    mail_search_args_unref(&search_args);

    return imap_client_notify_more(client);
}

void imap_client_notify_finished(struct client *client)
{
    if (client->notify_ctx != NULL)
        client->notify_ctx->notifying = FALSE;
}

static void notify_callback(struct imap_notify_namespace *notify_ns)
{
    o_stream_cork(notify_ns->ctx->client->output);
    imap_client_notify_ns(notify_ns);
    o_stream_uncork(notify_ns->ctx->client->output);
}

static enum mailbox_list_notify_event
imap_events_to_notify(enum imap_notify_event events)
{
    enum mailbox_list_notify_event ret = 0;

    if ((events & IMAP_NOTIFY_EVENT_MESSAGE_NEW) != 0) {
        ret |= MAILBOX_LIST_NOTIFY_APPENDS |
            MAILBOX_LIST_NOTIFY_UIDVALIDITY;
    }
    if ((events & IMAP_NOTIFY_EVENT_MESSAGE_EXPUNGE) != 0) {
        ret |= MAILBOX_LIST_NOTIFY_EXPUNGES |
            MAILBOX_LIST_NOTIFY_UIDVALIDITY;
    }
    if ((events & IMAP_NOTIFY_EVENT_FLAG_CHANGE) != 0) {
        ret |= MAILBOX_LIST_NOTIFY_SEEN_CHANGES |
            MAILBOX_LIST_NOTIFY_MODSEQ_CHANGES |
            MAILBOX_LIST_NOTIFY_UIDVALIDITY;
    }
    if ((events & IMAP_NOTIFY_EVENT_MAILBOX_NAME) != 0) {
        ret |= MAILBOX_LIST_NOTIFY_CREATE |
            MAILBOX_LIST_NOTIFY_DELETE |
            MAILBOX_LIST_NOTIFY_RENAME;
    }
    if ((events & IMAP_NOTIFY_EVENT_SUBSCRIPTION_CHANGE) != 0) {
        ret |= MAILBOX_LIST_NOTIFY_SUBSCRIBE |
            MAILBOX_LIST_NOTIFY_UNSUBSCRIBE;
    }
    return ret;
}

static void imap_notify_callback(struct mailbox *box, struct client *client)
{
    struct client_command_context *cmd;
    enum mailbox_sync_flags sync_flags = 0;

    i_assert(client->command_queue_size == 0);
    i_assert(box == client->mailbox);

    /* create a fake command to handle this */
    cmd = client_command_alloc(client);
    cmd->tag = "*";
    cmd->name = "NOTIFY-CALLBACK";
    client_command_init_finished(cmd);

    if (!client->notify_ctx->selected_immediate_expunges)
        sync_flags |= MAILBOX_SYNC_FLAG_NO_EXPUNGES;
    if (cmd_sync(cmd, sync_flags, 0, NULL))
        i_unreached();
    (void)cmd_sync_delayed(client);
}

static void imap_notify_watch_selected_mailbox(struct client *client)
{
    i_assert(client->command_queue_size == 0);

    if (client->mailbox == NULL) {
        /* mailbox not selected */
        return;
    }
    if (client->notify_ctx == NULL || !client->notify_ctx->selected_set) {
        /* client doesn't want selected mailbox notifications */
        return;

    }
    mailbox_notify_changes(client->mailbox, imap_notify_callback, client);
    client->notify_ctx->watching_mailbox = TRUE;
}

static void imap_notify_watch_timeout(struct client *client)
{
    timeout_remove(&client->notify_ctx->to_watch);
    imap_notify_watch_selected_mailbox(client);
}

void imap_client_notify_command_freed(struct client *client)
{
    struct imap_notify_context *ctx = client->notify_ctx;

    if (ctx == NULL)
        return;

    if (client->command_queue_size > 0) {
        /* don't add it until all commands are finished */
        i_assert(ctx->to_watch == NULL);
        return;
    }

    /* add mailbox watch back after a small delay. if another command
       is started this timeout is aborted. */
    ctx->to_watch = timeout_add(IMAP_NOTIFY_WATCH_ADD_DELAY_MSECS,
                    imap_notify_watch_timeout, client);
}

void imap_client_notify_command_allocated(struct client *client)
{
    struct imap_notify_context *ctx = client->notify_ctx;

    if (ctx == NULL)
        return;

    /* remove mailbox watcher before starting any commands */
    if (ctx->watching_mailbox) {
        mailbox_notify_changes_stop(client->mailbox);
        ctx->watching_mailbox = FALSE;
    }
    timeout_remove(&ctx->to_watch);
}

int imap_notify_begin(struct imap_notify_context *ctx)
{
    struct imap_notify_namespace *notify_ns;
    const struct imap_notify_mailboxes *notify_boxes;
    enum mailbox_list_notify_event notify_events;
    int ret = -1;

    array_foreach_modifiable(&ctx->namespaces, notify_ns) {
        notify_events = 0;
        array_foreach(&notify_ns->mailboxes, notify_boxes) {
            notify_events |=
                imap_events_to_notify(notify_boxes->events);
        }
        if (mailbox_list_notify_init(notify_ns->ns->list, notify_events,
                         &notify_ns->notify) < 0) {
            /* notifications not supported */
        } else {
            ret = 0;
            mailbox_list_notify_wait(notify_ns->notify,
                         notify_callback, notify_ns);
        }
    }
    /* enable NOTIFY as long as even one namespace supports it,
       ignore the rest */
    return ret;
}

void imap_notify_deinit(struct imap_notify_context **_ctx)
{
    struct imap_notify_context *ctx = *_ctx;
    struct imap_notify_namespace *notify_ns;

    *_ctx = NULL;

    array_foreach_modifiable(&ctx->namespaces, notify_ns) {
        if (notify_ns->notify != NULL)
            mailbox_list_notify_deinit(&notify_ns->notify);
    }
    timeout_remove(&ctx->to_watch);
    if (ctx->fetch_ctx != NULL)
        imap_fetch_free(&ctx->fetch_ctx);
    pool_unref(&ctx->pool);
}

void imap_notify_flush(struct imap_notify_context *ctx)
{
    struct imap_notify_namespace *notify_ns;

    array_foreach_modifiable(&ctx->namespaces, notify_ns) {
        if (notify_ns->notify != NULL)
            mailbox_list_notify_flush(notify_ns->notify);
    }
}