/*
* 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");
*
* Create an error and add additional explanation:
* error_setg(&err, "invalid quark");
* error_append_hint(&err, "Valid quarks are up, down, strange, "
* "charm, top, bottom.\n");
*
* Do *not* contract this to
* error_setg(&err, "invalid quark\n"
* "Valid quarks are up, down, strange, charm, top, bottom.");
*
* Report an error to the current monitor if we have one, else stderr:
* error_report_err(err);
* This frees the error object.
*
* Likewise, but with additional text prepended:
* error_reportf_err(err, "Could not frobnicate '%s': ", name);
*
* Report an error somewhere else:
* const char *msg = error_get_pretty(err);
* do with msg what needs to be done...
* error_free(err);
* Note that this loses hints added with error_append_hint().
*
* Handle an error without reporting it (just for completeness):
* error_free(err);
*
* Assert that an expected error occurred, but clean it up without
* reporting it (primarily useful in testsuites):
* error_free_or_abort(&err);
*
* Pass an existing error to the caller:
* error_propagate(errp, err);
* where Error **errp is a parameter, by convention the last one.
*
* Pass an existing error to the caller with the message modified:
* error_propagate(errp, err);
* error_prepend(errp, "Could not frobnicate '%s': ", name);
*
* 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);
*
* Call a function treating errors as fatal:
* foo(arg, &error_fatal);
*
* 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.
*
* Receive and accumulate multiple errors (first one wins):
* Error *err = NULL, *local_err = NULL;
* foo(arg, &err);
* bar(arg, &local_err);
* error_propagate(&err, local_err);
* if (err) {
* handle the error...
* }
*
* Do *not* "optimize" this to
* foo(arg, &err);
* bar(arg, &err); // WRONG!
* if (err) {
* handle the error...
* }
* because this may pass a non-null err to bar().
*/
#ifndef ERROR_H
#define ERROR_H
#include "qapi-types.h"
/*
* Overall category of an error.
* Based on the qapi type QapiErrorClass, but reproduced here for nicer
* enum names.
*/
typedef enum ErrorClass {
ERROR_CLASS_GENERIC_ERROR = QAPI_ERROR_CLASS_GENERICERROR,
ERROR_CLASS_COMMAND_NOT_FOUND = QAPI_ERROR_CLASS_COMMANDNOTFOUND,
ERROR_CLASS_DEVICE_ENCRYPTED = QAPI_ERROR_CLASS_DEVICEENCRYPTED,
ERROR_CLASS_DEVICE_NOT_ACTIVE = QAPI_ERROR_CLASS_DEVICENOTACTIVE,
ERROR_CLASS_DEVICE_NOT_FOUND = QAPI_ERROR_CLASS_DEVICENOTFOUND,
ERROR_CLASS_KVM_MISSING_CAP = QAPI_ERROR_CLASS_KVMMISSINGCAP,
} ErrorClass;
/*
* Get @err's human-readable error message.
*/
const char *error_get_pretty(const 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 &error_fatal, print a suitable message and exit(1).
* 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, ...
* The resulting message should be a single phrase, with no newline or
* trailing punctuation.
* Please don't error_setg(&error_fatal, ...), use error_report() and
* exit(), because that's more obvious.
* Likewise, don't error_setg(&error_abort, ...), use assert().
*/
#define error_setg(errp, fmt, ...) \
error_setg_internal((errp), __FILE__, __LINE__, __func__, \
(fmt), ## __VA_ARGS__)
void error_setg_internal(Error **errp,
const char *src, int line, const char *func,
const char *fmt, ...)
GCC_FMT_ATTR(5, 6);
/*
* 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.
*
* The value of errno (which usually can get clobbered by almost any
* function call) will be preserved.
*/
#define error_setg_errno(errp, os_error, fmt, ...) \
error_setg_errno_internal((errp), __FILE__, __LINE__, __func__, \
(os_error), (fmt), ## __VA_ARGS__)
void error_setg_errno_internal(Error **errp,
const char *fname, int line, const char *func,
int os_error, const char *fmt, ...)
GCC_FMT_ATTR(6, 7);
#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.
*/
#define error_setg_win32(errp, win32_err, fmt, ...) \
error_setg_win32_internal((errp), __FILE__, __LINE__, __func__, \
(win32_err), (fmt), ## __VA_ARGS__)
void error_setg_win32_internal(Error **errp,
const char *src, int line, const char *func,
int win32_err, const char *fmt, ...)
GCC_FMT_ATTR(6, 7);
#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 is &error_fatal, print a suitable message and
* exit(1).
* 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.
* Please don't error_propagate(&error_fatal, ...), use
* error_report_err() and exit(), because that's more obvious.
*/
void error_propagate(Error **dst_errp, Error *local_err);
/*
* Prepend some text to @errp's human-readable error message.
* The text is made by formatting @fmt, @ap like vprintf().
*/
void error_vprepend(Error **errp, const char *fmt, va_list ap);
/*
* Prepend some text to @errp's human-readable error message.
* The text is made by formatting @fmt, ... like printf().
*/
void error_prepend(Error **errp, const char *fmt, ...)
GCC_FMT_ATTR(2, 3);
/*
* Append a printf-style human-readable explanation to an existing error.
* @errp may be NULL, but not &error_fatal or &error_abort.
* Trivially the case if you call it only after error_setg() or
* error_propagate().
* May be called multiple times. The resulting hint should end with a
* newline.
*/
void error_append_hint(Error **errp, const char *fmt, ...)
GCC_FMT_ATTR(2, 3);
/*
* Convenience function to report open() failure.
*/
#define error_setg_file_open(errp, os_errno, filename) \
error_setg_file_open_internal((errp), __FILE__, __LINE__, __func__, \
(os_errno), (filename))
void error_setg_file_open_internal(Error **errp,
const char *src, int line, const char *func,
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 assert that *@errp is set, then silently free it.
*/
void error_free_or_abort(Error **errp);
/*
* Convenience function to error_report() and free @err.
*/
void error_report_err(Error *err);
/*
* Convenience function to error_prepend(), error_report() and free @err.
*/
void error_reportf_err(Error *err, const char *fmt, ...)
GCC_FMT_ATTR(2, 3);
/*
* 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.
*/
#define error_set(errp, err_class, fmt, ...) \
error_set_internal((errp), __FILE__, __LINE__, __func__, \
(err_class), (fmt), ## __VA_ARGS__)
void error_set_internal(Error **errp,
const char *src, int line, const char *func,
ErrorClass err_class, const char *fmt, ...)
GCC_FMT_ATTR(6, 7);
/*
* Special error destination to abort on error.
* See error_setg() and error_propagate() for details.
*/
extern Error *error_abort;
/*
* Special error destination to exit(1) on error.
* See error_setg() and error_propagate() for details.
*/
extern Error *error_fatal;
#endif
