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
  18 /**
  19  * Log severity level
  20  *
  21  * These levels correspond to syslog(2) log levels since they are widely used.
  22  */
  23 enum fuse_log_level {
  24     FUSE_LOG_EMERG,
  25     FUSE_LOG_ALERT,
  26     FUSE_LOG_CRIT,
  27     FUSE_LOG_ERR,
  28     FUSE_LOG_WARNING,
  29     FUSE_LOG_NOTICE,
  30     FUSE_LOG_INFO,
  31     FUSE_LOG_DEBUG
  32 };
  33
  34 /**
  35  * Log message handler function.
  36  *
  37  * This function must be thread-safe.  It may be called from any libfuse
  38  * function, including fuse_parse_cmdline() and other functions invoked before
  39  * a FUSE filesystem is created.
  40  *
  41  * Install a custom log message handler function using fuse_set_log_func().
  42  *
  43  * @param level log severity level
  44  * @param fmt sprintf-style format string including newline
  45  * @param ap format string arguments
  46  */
  47 typedef void (*fuse_log_func_t)(enum fuse_log_level level, const char *fmt,
  48                                 va_list ap);
  49
  50 /**
  51  * Install a custom log handler function.
  52  *
  53  * Log messages are emitted by libfuse functions to report errors and debug
  54  * information.  Messages are printed to stderr by default but this can be
  55  * overridden by installing a custom log message handler function.
  56  *
  57  * The log message handler function is global and affects all FUSE filesystems
  58  * created within this process.
  59  *
  60  * @param func a custom log message handler function or NULL to revert to
  61  *             the default
  62  */
  63 void fuse_set_log_func(fuse_log_func_t func);
  64
  65 /**
  66  * Emit a log message
  67  *
  68  * @param level severity level (FUSE_LOG_ERR, FUSE_LOG_DEBUG, etc)
  69  * @param fmt sprintf-style format string including newline
  70  */
  71 void fuse_log(enum fuse_log_level level, const char *fmt, ...);
  72
  73 #endif /* FUSE_LOG_H_ */