tools/virtiofsd/fuse_log.h

   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 /**
  20  * Log severity level
  21  *
  22  * These levels correspond to syslog(2) log levels since they are widely used.
  23  */
  24 enum fuse_log_level {
  25     FUSE_LOG_EMERG,
  26     FUSE_LOG_ALERT,
  27     FUSE_LOG_CRIT,
  28     FUSE_LOG_ERR,
  29     FUSE_LOG_WARNING,
  30     FUSE_LOG_NOTICE,
  31     FUSE_LOG_INFO,
  32     FUSE_LOG_DEBUG
  33 };
  34
  35 /**
  36  * Log message handler function.
  37  *
  38  * This function must be thread-safe.  It may be called from any libfuse
  39  * function, including fuse_parse_cmdline() and other functions invoked before
  40  * a FUSE filesystem is created.
  41  *
  42  * Install a custom log message handler function using fuse_set_log_func().
  43  *
  44  * @param level log severity level
  45  * @param fmt sprintf-style format string including newline
  46  * @param ap format string arguments
  47  */
  48 typedef void (*fuse_log_func_t)(enum fuse_log_level level, const char *fmt,
  49                                 va_list ap);
  50
  51 /**
  52  * Install a custom log handler function.
  53  *
  54  * Log messages are emitted by libfuse functions to report errors and debug
  55  * information.  Messages are printed to stderr by default but this can be
  56  * overridden by installing a custom log message handler function.
  57  *
  58  * The log message handler function is global and affects all FUSE filesystems
  59  * created within this process.
  60  *
  61  * @param func a custom log message handler function or NULL to revert to
  62  *             the default
  63  */
  64 void fuse_set_log_func(fuse_log_func_t func);
  65
  66 /**
  67  * Emit a log message
  68  *
  69  * @param level severity level (FUSE_LOG_ERR, FUSE_LOG_DEBUG, etc)
  70  * @param fmt sprintf-style format string including newline
  71  */
  72 void fuse_log(enum fuse_log_level level, const char *fmt, ...);
  73
  74 #endif /* FUSE_LOG_H_ */