acrn-hypervisor/devicemodel/log/kmsg_logger.c

104 lines
2.0 KiB
C

/*
* Copyright (C) 2018 Intel Corporation. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <errno.h>
#include <paths.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <stdbool.h>
#include <fcntl.h>
#include "log.h"
#define KMSG_DEV_NODE "/dev/kmsg"
#define KMSG_PREFIX "acrn_dm: "
#define KMSG_MAX_LEN (MAX_ONE_LOG_SIZE + 64)
#define DEFAULT_KMSG_LEVEL LOG_NOTICE
static int kmsg_fd = -1;
static uint8_t kmsg_log_level = DEFAULT_KMSG_LEVEL;
static bool kmsg_enabled = false;
static bool is_kmsg_enabled(void)
{
return kmsg_enabled;
}
static uint8_t get_kmsg_log_level(void)
{
return kmsg_log_level;
}
static int init_kmsg_logger(bool enable, uint8_t log_level)
{
kmsg_enabled = enable;
kmsg_log_level = log_level;
/* usually this init should be called once in DM whole life */
if (kmsg_fd > 0)
return kmsg_fd;
kmsg_fd = open(KMSG_DEV_NODE, O_RDWR | O_APPEND | O_NONBLOCK);
if (kmsg_fd < 0) {
kmsg_enabled = false;
perror(KMSG_PREFIX"open kmsg dev failed");
}
return kmsg_fd;
}
static void deinit_kmsg(void)
{
if (kmsg_fd > 0) {
close(kmsg_fd);
kmsg_fd = -1;
kmsg_enabled = false;
}
}
static void write_to_kmsg(const char *fmt, va_list args)
{
char *buf;
char kmsg_buf[KMSG_MAX_LEN] = KMSG_PREFIX;
int len, write_cnt;
if (kmsg_fd < 0)
return;
len = vasprintf(&buf, fmt, args);
if (len < 0)
return;
strncpy(kmsg_buf + strlen(KMSG_PREFIX), buf, KMSG_MAX_LEN - strlen(KMSG_PREFIX));
kmsg_buf[KMSG_MAX_LEN - 1] = '\0';
free(buf);
write_cnt = write(kmsg_fd, kmsg_buf, strnlen(kmsg_buf, KMSG_MAX_LEN));
if (write_cnt < 0) {
perror(KMSG_PREFIX"write kmsg failed");
close(kmsg_fd);
kmsg_fd = -1;
}
}
static struct logger_ops logger_kmsg = {
.name = "kmsg",
.is_enabled = is_kmsg_enabled,
.get_log_level = get_kmsg_log_level,
.init = init_kmsg_logger,
.deinit = deinit_kmsg,
.output = write_to_kmsg,
};
DEFINE_LOGGER_DEVICE(logger_kmsg);