1 files changed, 74 insertions, 0 deletions
diff --git a/tools/virtiofsd/fuse_log.h b/tools/virtiofsd/fuse_log.h
new file mode 100644
index 0000000000..bf6c11ff11
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+++ b/tools/virtiofsd/fuse_log.h
@@ -0,0 +1,74 @@
+/*
+ * FUSE: Filesystem in Userspace
+ * Copyright (C) 2019  Red Hat, Inc.
+ *
+ * This program can be distributed under the terms of the GNU LGPLv2.
+ * See the file COPYING.LIB.
+ */
+
+#ifndef FUSE_LOG_H_
+#define FUSE_LOG_H_
+
+/** @file
+ *
+ * This file defines the logging interface of FUSE
+ */
+
+#include <stdarg.h>
+
+/**
+ * Log severity level
+ *
+ * These levels correspond to syslog(2) log levels since they are widely used.
+ */
+enum fuse_log_level {
+    FUSE_LOG_EMERG,
+    FUSE_LOG_ALERT,
+    FUSE_LOG_CRIT,
+    FUSE_LOG_ERR,
+    FUSE_LOG_WARNING,
+    FUSE_LOG_NOTICE,
+    FUSE_LOG_INFO,
+    FUSE_LOG_DEBUG
+};
+
+/**
+ * Log message handler function.
+ *
+ * This function must be thread-safe.  It may be called from any libfuse
+ * function, including fuse_parse_cmdline() and other functions invoked before
+ * a FUSE filesystem is created.
+ *
+ * Install a custom log message handler function using fuse_set_log_func().
+ *
+ * @param level log severity level
+ * @param fmt sprintf-style format string including newline
+ * @param ap format string arguments
+ */
+typedef void (*fuse_log_func_t)(enum fuse_log_level level, const char *fmt,
+                                va_list ap);
+
+/**
+ * Install a custom log handler function.
+ *
+ * Log messages are emitted by libfuse functions to report errors and debug
+ * information.  Messages are printed to stderr by default but this can be
+ * overridden by installing a custom log message handler function.
+ *
+ * The log message handler function is global and affects all FUSE filesystems
+ * created within this process.
+ *
+ * @param func a custom log message handler function or NULL to revert to
+ *             the default
+ */
+void fuse_set_log_func(fuse_log_func_t func);
+
+/**
+ * Emit a log message
+ *
+ * @param level severity level (FUSE_LOG_ERR, FUSE_LOG_DEBUG, etc)
+ * @param fmt sprintf-style format string including newline
+ */
+void fuse_log(enum fuse_log_level level, const char *fmt, ...);
+
+#endif /* FUSE_LOG_H_ */