| 1 | /* |
| 2 | * event-notifier-notification.c |
| 3 | * |
| 4 | * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com> |
| 5 | * |
| 6 | * This library is free software; you can redistribute it and/or |
| 7 | * modify it under the terms of the GNU Lesser General Public |
| 8 | * License as published by the Free Software Foundation; only |
| 9 | * version 2.1 of the License. |
| 10 | * |
| 11 | * This library is distributed in the hope that it will be useful, |
| 12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | * Lesser General Public License for more details. |
| 15 | * |
| 16 | * You should have received a copy of the GNU Lesser General Public |
| 17 | * License along with this library; if not, write to the Free Software |
| 18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 19 | */ |
| 20 | |
| 21 | #define _LGPL_SOURCE |
| 22 | |
| 23 | #include <errno.h> |
| 24 | #include <lttng/ust-events.h> |
| 25 | #include <usterr-signal-safe.h> |
| 26 | |
| 27 | #include "share.h" |
| 28 | |
| 29 | void lttng_event_notifier_notification_send( |
| 30 | struct lttng_event_notifier *event_notifier) |
| 31 | { |
| 32 | /* |
| 33 | * We want this write to be atomic AND non-blocking, meaning that we |
| 34 | * want to write either everything OR nothing. |
| 35 | * According to `pipe(7)`, writes that are smaller that the `PIPE_BUF` |
| 36 | * value must be atomic, so we assert that the message we send is less |
| 37 | * than PIPE_BUF. |
| 38 | */ |
| 39 | struct lttng_ust_event_notifier_notification notif; |
| 40 | ssize_t ret; |
| 41 | |
| 42 | assert(event_notifier); |
| 43 | assert(event_notifier->group); |
| 44 | assert(sizeof(notif) <= PIPE_BUF); |
| 45 | |
| 46 | notif.token = event_notifier->user_token; |
| 47 | |
| 48 | ret = patient_write(event_notifier->group->notification_fd, ¬if, |
| 49 | sizeof(notif)); |
| 50 | if (ret == -1) { |
| 51 | if (errno == EAGAIN) { |
| 52 | DBG("Cannot send event notifier notification without blocking: %s", |
| 53 | strerror(errno)); |
| 54 | } else { |
| 55 | DBG("Error to sending event notifier notification: %s", |
| 56 | strerror(errno)); |
| 57 | abort(); |
| 58 | } |
| 59 | } |
| 60 | } |