xref: /third_party/libfuse/include/fuse_log.h (revision 6881f68f) 
1/*
2  FUSE: Filesystem in Userspace
3  Copyright (C) 2019  Red Hat, Inc.
4
5  This program can be distributed under the terms of the GNU LGPLv2.
6  See the file COPYING.LIB.
7*/
8
9#ifndef FUSE_LOG_H_
10#define FUSE_LOG_H_
11
12/** @file
13 *
14 * This file defines the logging interface of FUSE
15 */
16
17#include <stdarg.h>
18
19#ifdef __cplusplus
20extern "C" {
21#endif
22
23/**
24 * Log severity level
25 *
26 * These levels correspond to syslog(2) log levels since they are widely used.
27 */
28enum fuse_log_level {
29	FUSE_LOG_EMERG,
30	FUSE_LOG_ALERT,
31	FUSE_LOG_CRIT,
32	FUSE_LOG_ERR,
33	FUSE_LOG_WARNING,
34	FUSE_LOG_NOTICE,
35	FUSE_LOG_INFO,
36	FUSE_LOG_DEBUG
37};
38
39/**
40 * Log message handler function.
41 *
42 * This function must be thread-safe.  It may be called from any libfuse
43 * function, including fuse_parse_cmdline() and other functions invoked before
44 * a FUSE filesystem is created.
45 *
46 * Install a custom log message handler function using fuse_set_log_func().
47 *
48 * @param level log severity level
49 * @param fmt sprintf-style format string including newline
50 * @param ap format string arguments
51 */
52typedef void (*fuse_log_func_t)(enum fuse_log_level level,
53				const char *fmt, va_list ap);
54
55/**
56 * Install a custom log handler function.
57 *
58 * Log messages are emitted by libfuse functions to report errors and debug
59 * information.  Messages are printed to stderr by default but this can be
60 * overridden by installing a custom log message handler function.
61 *
62 * The log message handler function is global and affects all FUSE filesystems
63 * created within this process.
64 *
65 * @param func a custom log message handler function or NULL to revert to
66 *             the default
67 */
68void fuse_set_log_func(fuse_log_func_t func);
69
70/**
71 * Emit a log message
72 *
73 * @param level severity level (FUSE_LOG_ERR, FUSE_LOG_DEBUG, etc)
74 * @param fmt sprintf-style format string including newline
75 */
76void fuse_log(enum fuse_log_level level, const char *fmt, ...);
77
78#ifdef __cplusplus
79}
80#endif
81
82#endif /* FUSE_LOG_H_ */
83