fuse_log.c

/*
  FUSE: Filesystem in Userspace
  Copyright (C) 2019  Red Hat, Inc.
 
  Logging API.
 
  This program can be distributed under the terms of the GNU LGPLv2.
  See the file COPYING.LIB
*/
 
#include "fuse_log.h"
 
#include <stdarg.h>
#include <stdio.h>
#include <stdbool.h>
#include <syslog.h>
 
#define MAX_SYSLOG_LINE_LEN 512
 
static bool to_syslog = false;
 
static void default_log_func(__attribute__((unused)) enum fuse_log_level level,
                             const char *fmt, va_list ap)
{
        if (to_syslog) {
                int sys_log_level = LOG_ERR;
 
                /*
                 * with glibc fuse_log_level has identical values as
                 * syslog levels, but we also support BSD - better we convert to
                 * be sure.
                 */
                switch (level) {
                case FUSE_LOG_DEBUG:
                        sys_log_level = LOG_DEBUG;
                        break;
                case FUSE_LOG_INFO:
                        sys_log_level = LOG_INFO;
                        break;
                case FUSE_LOG_NOTICE:
                        sys_log_level = LOG_NOTICE;
                        break;
                case FUSE_LOG_WARNING:
                        sys_log_level = LOG_WARNING;
                        break;
                case FUSE_LOG_ERR:
                        sys_log_level = LOG_ERR;
                        break;
                case FUSE_LOG_CRIT:
                        sys_log_level = LOG_CRIT;
                        break;
                case FUSE_LOG_ALERT:
                        sys_log_level = LOG_ALERT;
                        break;
                case FUSE_LOG_EMERG:
                        sys_log_level = LOG_EMERG;
                }
 
                char log[MAX_SYSLOG_LINE_LEN];
                vsnprintf(log, MAX_SYSLOG_LINE_LEN, fmt, ap);
                syslog(sys_log_level, "%s", log);
        } else {
                vfprintf(stderr, fmt, ap);
        }
}
 
static fuse_log_func_t log_func = default_log_func;
 
void fuse_set_log_func(fuse_log_func_t func)
{
        if (!func)
                func = default_log_func;
 
        log_func = func;
}
 
void fuse_log(enum fuse_log_level level, const char *fmt, ...)
{
        va_list ap;
 
        va_start(ap, fmt);
        log_func(level, fmt, ap);
        va_end(ap);
}
 
void fuse_log_enable_syslog(const char *ident, int option, int facility)
{
        to_syslog = true;
 
        openlog(ident, option, facility);
}
 
void fuse_log_close_syslog(void)
{
        closelog();
}