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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#pragma once
#include <syslog.h>
#include <sd-event.h>
/* All our long-running services should implement a SIGRTMIN+18 handler that can be used to trigger certain
* actions that affect service runtime. The specific action is indicated via the "value integer" you can pass
* along realtime signals. This is mostly intended for debugging purposes and is entirely asynchronous in
* nature. Specifically, these are the commands:
*
* Currently available operations:
*
* • Change maximum log level
* • Change log target
* • Invoke memory trimming, like under memory pressure
* • Write glibc malloc() allocation info to logs
*
* How to use this? Via a command like the following:
*
* /usr/bin/kill -s RTMIN+18 -q 768 1
*
* (This will tell PID 1 to trim its memory use.)
*
* or:
*
* systemctl kill --kill-value=0x300 -s RTMIN+18 systemd-journald
*
* (This will tell journald to trim its memory use.)
*/
enum {
_COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE = 0x100,
COMMON_SIGNAL_COMMAND_LOG_EMERG = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_EMERG,
COMMON_SIGNAL_COMMAND_LOG_ALERT = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_ALERT,
COMMON_SIGNAL_COMMAND_LOG_CRIT = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_CRIT,
COMMON_SIGNAL_COMMAND_LOG_ERR = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_ERR,
COMMON_SIGNAL_COMMAND_LOG_WARNING = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_WARNING,
COMMON_SIGNAL_COMMAND_LOG_NOTICE = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_NOTICE,
COMMON_SIGNAL_COMMAND_LOG_INFO = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_INFO,
COMMON_SIGNAL_COMMAND_LOG_DEBUG = _COMMON_SIGNAL_COMMAND_LOG_LEVEL_BASE + LOG_DEBUG,
_COMMON_SIGNAL_COMMAND_LOG_LEVEL_END = COMMON_SIGNAL_COMMAND_LOG_DEBUG,
COMMON_SIGNAL_COMMAND_CONSOLE = 0x200,
COMMON_SIGNAL_COMMAND_JOURNAL,
COMMON_SIGNAL_COMMAND_KMSG,
COMMON_SIGNAL_COMMAND_NULL,
COMMON_SIGNAL_COMMAND_MEMORY_PRESSURE = 0x300,
COMMON_SIGNAL_COMMAND_MALLOC_INFO,
/* Private signals start at 0x500 */
_COMMON_SIGNAL_COMMAND_PRIVATE_BASE = 0x500,
_COMMON_SIGNAL_COMMAND_PRIVATE_END = 0xfff,
};
struct sigrtmin18_info {
sd_event_handler_t memory_pressure_handler;
void *memory_pressure_userdata;
};
int sigrtmin18_handler(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata);
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