/*
* QEMU Error Objects
*
* Copyright IBM, Corp. 2011
* Copyright (C) 2011-2015 Red Hat, Inc.
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Markus Armbruster <armbru@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2. See
* the COPYING.LIB file in the top-level directory.
*/
/*
* Error reporting system loosely patterned after Glib's GError.
*
* Create an error:
* error_setg(&err, "situation normal, all fouled up");
*
* Report an error to stderr:
* error_report_err(err);
* This frees the error object.
*
* Report an error somewhere else:
* const char *msg = error_get_pretty(err);
* do with msg what needs to be done...
* error_free(err);
*
* Handle an error without reporting it (just for completeness):
* error_free(err);
*
* Pass an existing error to the caller:
* error_propagate(errp, err);
* where Error **errp is a parameter, by convention the last one.
*
* Create a new error and pass it to the caller:
* error_setg(errp, "situation normal, all fouled up");
*
* Call a function and receive an error from it:
* Error *err = NULL;
* foo(arg, &err);
* if (err) {
* handle the error...
* }
*
* Call a function ignoring errors:
* foo(arg, NULL);
*
* Call a function aborting on errors:
* foo(arg, &error_abort);
*
* Receive an error and pass it on to the caller:
* Error *err = NULL;
* foo(arg, &err);
* if (err) {
* handle the error...
* error_propagate(errp, err);
* }
* where Error **errp is a parameter, by convention the last one.
*
* Do *not* "optimize" this to
* foo(arg, errp);
* if (*errp) { // WRONG!
* handle the error...
* }
* because errp may be NULL!
*
* But when all you do with the error is pass it on, please use
* foo(arg, errp);
* for readability.
*/
#ifndef ERROR_H
#define ERROR_H
#include "qemu/compiler.h"
#include "qapi-types.h"
#include <stdbool.h>
/*
* Opaque error object.
*/
typedef struct Error Error;
/*
* Get @err's human-readable error message.
*/
const char *error_get_pretty(Error *err);
/*
* Get @err's error class.
* Note: use of error classes other than ERROR_CLASS_GENERIC_ERROR is
* strongly discouraged.
*/
ErrorClass error_get_class(const Error *err);
/*
* Create a new error object and assign it to *@errp.
* If @errp is NULL, the error is ignored. Don't bother creating one
* then.
* If @errp is &error_abort, print a suitable message and abort().
* If @errp is anything else, *@errp must be NULL.
* The new error's class is ERROR_CLASS_GENERIC_ERROR, and its
* human-readable error message is made from printf-style @fmt, ...
*/
void error_setg(Error **errp, const char *fmt, ...)
GCC_FMT_ATTR(2, 3);
/*
* Just like error_setg(), with @os_error info added to the message.
* If @os_error is non-zero, ": " + strerror(os_error) is appended to
* the human-readable error message.
*/
void error_setg_errno(Error **errp, int os_error, const char *fmt, ...)
GCC_FMT_ATTR(3, 4);
#ifdef _WIN32
/*
* Just like error_setg(), with @win32_error info added to the message.
* If @win32_error is non-zero, ": " + g_win32_error_message(win32_err)
* is appended to the human-readable error message.
*/
void error_setg_win32(Error **errp, int win32_err, const char *fmt, ...)
GCC_FMT_ATTR(3, 4);
#endif
/*
* Propagate error object (if any) from @local_err to @dst_errp.
* If @local_err is NULL, do nothing (because there's nothing to
* propagate).
* Else, if @dst_errp is NULL, errors are being ignored. Free the
* error object.
* Else, if @dst_errp is &error_abort, print a suitable message and
* abort().
* Else, if @dst_errp already contains an error, ignore this one: free
* the error object.
* Else, move the error object from @local_err to *@dst_errp.
* On return, @local_err is invalid.
*/
void error_propagate(Error **dst_errp, Error *local_err);
/*
* Convenience function to report open() failure.
*/
void error_setg_file_open(Error **errp, int os_errno, const char *filename);
/*
* Return an exact copy of @err.
*/
Error *error_copy(const Error *err);
/*
* Free @err.
* @err may be NULL.
*/
void error_free(Error *err);
/*
* Convenience function to error_report() and free @err.
*/
void error_report_err(Error *);
/*
* Just like error_setg(), except you get to specify the error class.
* Note: use of error classes other than ERROR_CLASS_GENERIC_ERROR is
* strongly discouraged.
*/
void error_set(Error **errp, ErrorClass err_class, const char *fmt, ...)
GCC_FMT_ATTR(3, 4);
/*
* Pass to error_setg() & friends to abort() on error.
*/
extern Error *error_abort;
#endif
