DM: add disk-logger to write log into file system

disk-logger used to save persistent log as file in disk.
log path: /var/log/acrn-dm/

each log file size is 2MB; default 8 log files; the log
files' suffix will be increased; when file count more than 8,
the last one added, the first one is removed, like form 1-8 to
2-9 to 3-10 ...

Tracked-On: #3012
Signed-off-by: Minggui Cao <minggui.cao@intel.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>

devicemodel/Makefile

@@ -153,6 +153,7 @@ SRCS += arch/x86/pm.c
 # log
 SRCS += log/log.c
 SRCS += log/kmsg_logger.c
+SRCS += log/disk_logger.c
 
 OBJS := $(patsubst %.c,$(DM_OBJDIR)/%.o,$(SRCS))
 

devicemodel/log/disk_logger.c

@@ -0,0 +1,202 @@
+/*
+ * 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 <dirent.h>
+#include <time.h>
+
+#include "dm.h"
+#include "log.h"
+
+#define DISK_PREFIX  "disk_log: "
+
+#define LOG_PATH_NODE "/var/log/acrn-dm/"
+#define LOG_NAME_PREFIX  "%s_log_"
+#define LOG_NAME_FMT  "%s%s_log_%d" /* %s-->vm1/vm2..., %d-->1/2/3/4... */
+#define LOG_DELIMITER "\n\n----------------new vm instance------------------\n\n\0"
+
+#define FILE_NAME_LENGTH  96
+
+#define LOG_SIZE_LIMIT    0x200000 /* one log file size limit */
+#define LOG_FILES_COUNT   8
+
+static int disk_fd = -1;
+static uint32_t cur_log_size;
+static uint16_t cur_file_index;
+
+static uint8_t disk_log_level = LOG_DEBUG;
+static bool disk_log_enabled = false;
+
+#define DISK_LOG_MAX_LEN    (MAX_ONE_LOG_SIZE + 32)
+#define INDEX_AFTER(a, b) ((short int)b - (short int)a < 0)
+
+static bool is_disk_log_enabled(void)
+{
+	return disk_log_enabled;
+}
+
+static uint8_t get_disk_log_level(void)
+{
+	return disk_log_level;
+}
+
+static int probe_disk_log_file(void)
+{
+	char file_name[FILE_NAME_LENGTH];
+	struct dirent *pdir;
+	struct stat st;
+	int length;
+	uint16_t index = 0, tmp;
+	bool is_first_file = true;
+	DIR *dir;
+
+	if (stat(LOG_PATH_NODE, &st)) {
+		if (mkdir(LOG_PATH_NODE, 0644)) {
+			printf(DISK_PREFIX"create path: %s failed! Error: %s\n",
+				LOG_PATH_NODE, strerror(errno));
+			return -1;
+		}
+	}
+
+	dir = opendir(LOG_PATH_NODE);
+	if (!dir) {
+		printf(DISK_PREFIX" open %s failed! Error: %s\n",
+			LOG_PATH_NODE, strerror(errno));
+		return -1;
+	}
+
+	snprintf(file_name, FILE_NAME_LENGTH - 1, LOG_NAME_PREFIX, vmname);
+	length = strlen(file_name);
+
+	while ((pdir = readdir(dir)) != NULL) {
+		if (!(pdir->d_type & DT_REG))
+			continue;
+
+		if (strncmp(pdir->d_name, file_name, length) != 0)
+			continue;
+
+		tmp = (uint16_t)atoi(pdir->d_name + length);
+		if (is_first_file) {
+			is_first_file = false;
+			index = tmp;
+		} else if (INDEX_AFTER(tmp, index)) {
+			index = tmp;
+		}
+	}
+
+	snprintf(file_name, FILE_NAME_LENGTH - 1, LOG_NAME_FMT, LOG_PATH_NODE, vmname, index);
+	disk_fd = open(file_name, O_RDWR | O_CREAT | O_APPEND, 0644);
+	if (disk_fd < 0) {
+		printf(DISK_PREFIX" open %s failed! Error: %s\n", file_name, strerror(errno));
+		return -1;
+	}
+
+	if (write(disk_fd, LOG_DELIMITER, strlen(LOG_DELIMITER)) < 0) {
+		printf(DISK_PREFIX" write %s failed! Error: %s\n", file_name, strerror(errno));
+		return -1;
+	}
+
+	fstat(disk_fd, &st);
+	cur_log_size = st.st_size;
+	cur_file_index = index;
+
+	return 0;
+}
+
+static int init_disk_logger(bool enable, uint8_t log_level)
+{
+	disk_log_enabled = enable;
+	disk_log_level = log_level;
+
+	return 1;
+}
+
+static void deinit_disk_logger(void)
+{
+	if (disk_fd > 0) {
+		disk_log_enabled = false;
+
+		fsync(disk_fd);
+		close(disk_fd);
+		disk_fd = -1;
+	}
+}
+
+static void write_to_disk(const char *fmt, va_list args)
+{
+	char buffer[DISK_LOG_MAX_LEN];
+	char *file_name = buffer;
+	int len1, len2;
+	int write_cnt;
+	struct timespec times = {0, 0};
+
+	if ((disk_fd < 0) && disk_log_enabled) {
+		/**
+		 * usually this probe just be called once in DM whole life; but we need use vmname in
+		 * probe_disk_log_file, it can't be called in init_disk_logger for vmname not inited then,
+		 * so call it here.
+		 */
+		if (probe_disk_log_file() < 0) {
+			disk_log_enabled = false;
+			return;
+		}
+	}
+
+	clock_gettime(CLOCK_MONOTONIC, &times);
+	len1 = sprintf(buffer, "[%5lu.%06lu] ", times.tv_sec, times.tv_nsec / 1000);
+	len2 = vsnprintf(buffer + len1, MAX_ONE_LOG_SIZE, fmt, args);
+
+	write_cnt = write(disk_fd, buffer, len1 + len2);
+	if (write_cnt < 0) {
+		perror(DISK_PREFIX"write disk failed");
+		close(disk_fd);
+		disk_fd = -1;
+		return;
+	}
+
+	cur_log_size += write_cnt;
+	if (cur_log_size > LOG_SIZE_LIMIT) {
+
+		cur_file_index++;
+
+		/* remove the first old log file, to add a new one */
+		snprintf(file_name, FILE_NAME_LENGTH - 1, LOG_NAME_FMT,
+			LOG_PATH_NODE, vmname, (uint16_t)(cur_file_index - LOG_FILES_COUNT));
+		remove(file_name);
+
+		snprintf(file_name, FILE_NAME_LENGTH - 1, LOG_NAME_FMT,
+			LOG_PATH_NODE, vmname, cur_file_index);
+
+		close(disk_fd);
+		disk_fd = open(file_name, O_RDWR | O_CREAT, 0644);
+		if (disk_fd < 0) {
+			printf(DISK_PREFIX" open %s failed! Error: %s\n", file_name, strerror(errno));
+			return;
+		}
+		cur_log_size = 0;
+	}
+}
+
+static struct logger_ops logger_disk = {
+	.name = "disk",
+	.is_enabled = is_disk_log_enabled,
+	.get_log_level = get_disk_log_level,
+	.init = init_disk_logger,
+	.deinit = deinit_disk_logger,
+	.output = write_to_disk,
+};
+
+DEFINE_LOGGER_DEVICE(logger_disk);