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/* SPDX-License-Identifier: MIT
*
* Copyright © 2018-2019 WireGuard LLC. All Rights Reserved.
*/
#include <string.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdatomic.h>
#include <stdbool.h>
#include <time.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/mman.h>
#include "ringlogger.h"
enum {
MAX_LOG_LINE_LENGTH = 512,
MAX_LINES = 2048,
MAGIC = 0xabadbeefU
};
struct log_line {
atomic_uint_fast64_t time_ns;
char line[MAX_LOG_LINE_LENGTH];
};
struct log {
atomic_uint_fast32_t next_index;
struct log_line lines[MAX_LINES];
uint32_t magic;
};
void write_msg_to_log(struct log *log, const char *tag, const char *msg)
{
uint32_t index;
struct log_line *line;
struct timespec ts;
// Race: This isn't synchronized with the fetch_add below, so items might be slightly out of order.
clock_gettime(CLOCK_REALTIME, &ts);
// Race: More than MAX_LINES writers and this will clash.
index = atomic_fetch_add(&log->next_index, 1);
line = &log->lines[index % MAX_LINES];
// Race: Before this line executes, we'll display old data after new data.
atomic_store(&line->time_ns, 0);
memset(line->line, 0, MAX_LOG_LINE_LENGTH);
snprintf(line->line, MAX_LOG_LINE_LENGTH, "[%s] %s", tag, msg);
atomic_store(&line->time_ns, ts.tv_sec * 1000000000ULL + ts.tv_nsec);
msync(&log->next_index, sizeof(log->next_index), MS_ASYNC);
msync(line, sizeof(*line), MS_ASYNC);
}
int write_log_to_file(const char *file_name, const struct log *input_log)
{
struct log *log;
uint32_t l, i;
FILE *file;
int ret;
log = malloc(sizeof(*log));
if (!log)
return -errno;
memcpy(log, input_log, sizeof(*log));
file = fopen(file_name, "w");
if (!file) {
free(log);
return -errno;
}
for (l = 0, i = log->next_index; l < MAX_LINES; ++l, ++i) {
const struct log_line *line = &log->lines[i % MAX_LINES];
time_t seconds = line->time_ns / 1000000000ULL;
uint32_t useconds = (line->time_ns % 1000000000ULL) / 1000ULL;
struct tm tm;
if (!line->time_ns)
continue;
if (!localtime_r(&seconds, &tm))
goto err;
if (fprintf(file, "%04d-%02d-%02d %02d:%02d:%02d.%06d: %s\n",
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
tm.tm_hour, tm.tm_min, tm.tm_sec, useconds,
line->line) < 0)
goto err;
}
errno = 0;
err:
ret = -errno;
fclose(file);
free(log);
return ret;
}
uint32_t view_lines_from_cursor(const struct log *input_log, uint32_t cursor, void(*cb)(const char *, uint64_t))
{
struct log *log;
uint32_t l, i = cursor;
log = malloc(sizeof(*log));
if (!log)
return cursor;
memcpy(log, input_log, sizeof(*log));
if (i == -1)
i = log->next_index;
for (l = 0; l < MAX_LINES; ++l, ++i) {
const struct log_line *line = &log->lines[i % MAX_LINES];
if (cursor != -1 && i % MAX_LINES == log->next_index % MAX_LINES)
break;
if (!line->time_ns) {
if (cursor == -1)
continue;
else
break;
}
cb(line->line, line->time_ns);
cursor = (i + 1) % MAX_LINES;
}
free(log);
return cursor;
}
struct log *open_log(const char *file_name)
{
int fd;
struct log *log;
fd = open(file_name, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
if (fd < 0)
return NULL;
if (ftruncate(fd, sizeof(*log)))
goto err;
log = mmap(NULL, sizeof(*log), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (log == MAP_FAILED)
goto err;
close(fd);
if (log->magic != MAGIC) {
memset(log, 0, sizeof(*log));
log->magic = MAGIC;
msync(log, sizeof(*log), MS_ASYNC);
}
return log;
err:
close(fd);
return NULL;
}
void close_log(struct log *log)
{
munmap(log, sizeof(*log));
}
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