GDBusError

GDBusError — Mapping D-Bus errors to and from GError

Synopsis

#include <gio/gio.h>

enum                GDBusError;
#define             G_DBUS_ERROR
gboolean            g_dbus_error_is_remote_error        (const GError *error);
gchar *             g_dbus_error_get_remote_error       (const GError *error);
gboolean            g_dbus_error_strip_remote_error     (GError *error);
                    GDBusErrorEntry;
void                g_dbus_error_register_error_domain  (const gchar *error_domain_quark_name,
                                                         volatile gsize *quark_volatile,
                                                         const GDBusErrorEntry *entries,
                                                         guint num_entries);
gboolean            g_dbus_error_register_error         (GQuark error_domain,
                                                         gint error_code,
                                                         const gchar *dbus_error_name);
gboolean            g_dbus_error_unregister_error       (GQuark error_domain,
                                                         gint error_code,
                                                         const gchar *dbus_error_name);
GError *            g_dbus_error_new_for_dbus_error     (const gchar *dbus_error_name,
                                                         const gchar *dbus_error_message);
void                g_dbus_error_set_dbus_error         (GError **error,
                                                         const gchar *dbus_error_name,
                                                         const gchar *dbus_error_message,
                                                         const gchar *format,
                                                         ...);
void                g_dbus_error_set_dbus_error_valist  (GError **error,
                                                         const gchar *dbus_error_name,
                                                         const gchar *dbus_error_message,
                                                         const gchar *format,
                                                         va_list var_args);
gchar *             g_dbus_error_encode_gerror          (const GError *error);

Object Hierarchy

  GEnum
   +----GDBusError

Description

All facilities that return errors from remote methods (such as g_dbus_connection_call_sync()) use GError to represent both D-Bus errors (e.g. errors returned from the other peer) and locally in-process generated errors.

To check if a returned GError is an error from a remote peer, use g_dbus_error_is_remote_error(). To get the actual D-Bus error name, use g_dbus_error_get_remote_error(). Before presenting an error, always use g_dbus_error_strip_remote_error().

In addition, facilities used to return errors to a remote peer also use GError. See g_dbus_method_invocation_return_error() for discussion about how the D-Bus error name is set.

Applications can associate a GError error domain with a set of D-Bus errors in order to automatically map from D-Bus errors to GError and back. This is typically done in the function returning the GQuark for the error domain:

Example 1. Error Registration

/* foo-bar-error.h: */

#define FOO_BAR_ERROR (foo_bar_error_quark ())
GQuark foo_bar_error_quark (void);

typedef enum
{
  FOO_BAR_ERROR_FAILED,
  FOO_BAR_ERROR_ANOTHER_ERROR,
  FOO_BAR_ERROR_SOME_THIRD_ERROR,
} FooBarError;

/* foo-bar-error.c: */

static const GDBusErrorEntry foo_bar_error_entries[] =
{
  {FOO_BAR_ERROR_FAILED,           "org.project.Foo.Bar.Error.Failed"},
  {FOO_BAR_ERROR_ANOTHER_ERROR,    "org.project.Foo.Bar.Error.AnotherError"},
  {FOO_BAR_ERROR_SOME_THIRD_ERROR, "org.project.Foo.Bar.Error.SomeThirdError"},
};

GQuark
foo_bar_error_quark (void)
{
  static volatile gsize quark_volatile = 0;
  g_dbus_error_register_error_domain ("foo-bar-error-quark",
                                      &quark_volatile,
                                      foo_bar_error_entries,
                                      G_N_ELEMENTS (foo_bar_error_entries));
  G_STATIC_ASSERT (G_N_ELEMENTS (foo_bar_error_entries) - 1 == FOO_BAR_ERROR_SOME_THIRD_ERROR);
  return (GQuark) quark_volatile;
}

With this setup, a D-Bus peer can transparently pass e.g. FOO_BAR_ERROR_ANOTHER_ERROR and other peers will see the D-Bus error name org.project.Foo.Bar.Error.AnotherError. If the other peer is using GDBus, the peer will see also FOO_BAR_ERROR_ANOTHER_ERROR instead of G_IO_ERROR_DBUS_ERROR. Note that GDBus clients can still recover org.project.Foo.Bar.Error.AnotherError using g_dbus_error_get_remote_error().

Note that errors in the G_DBUS_ERROR error domain is intended only for returning errors from a remote message bus process. Errors generated locally in-process by e.g. GDBusConnection is from the G_IO_ERROR domain.

Details

enum GDBusError

typedef enum
{
  /* Well-known errors in the org.freedesktop.DBus.Error namespace */
  G_DBUS_ERROR_FAILED,                           /* org.freedesktop.DBus.Error.Failed */
  G_DBUS_ERROR_NO_MEMORY,                        /* org.freedesktop.DBus.Error.NoMemory */
  G_DBUS_ERROR_SERVICE_UNKNOWN,                  /* org.freedesktop.DBus.Error.ServiceUnknown */
  G_DBUS_ERROR_NAME_HAS_NO_OWNER,                /* org.freedesktop.DBus.Error.NameHasNoOwner */
  G_DBUS_ERROR_NO_REPLY,                         /* org.freedesktop.DBus.Error.NoReply */
  G_DBUS_ERROR_IO_ERROR,                         /* org.freedesktop.DBus.Error.IOError */
  G_DBUS_ERROR_BAD_ADDRESS,                      /* org.freedesktop.DBus.Error.BadAddress */
  G_DBUS_ERROR_NOT_SUPPORTED,                    /* org.freedesktop.DBus.Error.NotSupported */
  G_DBUS_ERROR_LIMITS_EXCEEDED,                  /* org.freedesktop.DBus.Error.LimitsExceeded */
  G_DBUS_ERROR_ACCESS_DENIED,                    /* org.freedesktop.DBus.Error.AccessDenied */
  G_DBUS_ERROR_AUTH_FAILED,                      /* org.freedesktop.DBus.Error.AuthFailed */
  G_DBUS_ERROR_NO_SERVER,                        /* org.freedesktop.DBus.Error.NoServer */
  G_DBUS_ERROR_TIMEOUT,                          /* org.freedesktop.DBus.Error.Timeout */
  G_DBUS_ERROR_NO_NETWORK,                       /* org.freedesktop.DBus.Error.NoNetwork */
  G_DBUS_ERROR_ADDRESS_IN_USE,                   /* org.freedesktop.DBus.Error.AddressInUse */
  G_DBUS_ERROR_DISCONNECTED,                     /* org.freedesktop.DBus.Error.Disconnected */
  G_DBUS_ERROR_INVALID_ARGS,                     /* org.freedesktop.DBus.Error.InvalidArgs */
  G_DBUS_ERROR_FILE_NOT_FOUND,                   /* org.freedesktop.DBus.Error.FileNotFound */
  G_DBUS_ERROR_FILE_EXISTS,                      /* org.freedesktop.DBus.Error.FileExists */
  G_DBUS_ERROR_UNKNOWN_METHOD,                   /* org.freedesktop.DBus.Error.UnknownMethod */
  G_DBUS_ERROR_TIMED_OUT,                        /* org.freedesktop.DBus.Error.TimedOut */
  G_DBUS_ERROR_MATCH_RULE_NOT_FOUND,             /* org.freedesktop.DBus.Error.MatchRuleNotFound */
  G_DBUS_ERROR_MATCH_RULE_INVALID,               /* org.freedesktop.DBus.Error.MatchRuleInvalid */
  G_DBUS_ERROR_SPAWN_EXEC_FAILED,                /* org.freedesktop.DBus.Error.Spawn.ExecFailed */
  G_DBUS_ERROR_SPAWN_FORK_FAILED,                /* org.freedesktop.DBus.Error.Spawn.ForkFailed */
  G_DBUS_ERROR_SPAWN_CHILD_EXITED,               /* org.freedesktop.DBus.Error.Spawn.ChildExited */
  G_DBUS_ERROR_SPAWN_CHILD_SIGNALED,             /* org.freedesktop.DBus.Error.Spawn.ChildSignaled */
  G_DBUS_ERROR_SPAWN_FAILED,                     /* org.freedesktop.DBus.Error.Spawn.Failed */
  G_DBUS_ERROR_SPAWN_SETUP_FAILED,               /* org.freedesktop.DBus.Error.Spawn.FailedToSetup */
  G_DBUS_ERROR_SPAWN_CONFIG_INVALID,             /* org.freedesktop.DBus.Error.Spawn.ConfigInvalid */
  G_DBUS_ERROR_SPAWN_SERVICE_INVALID,            /* org.freedesktop.DBus.Error.Spawn.ServiceNotValid */
  G_DBUS_ERROR_SPAWN_SERVICE_NOT_FOUND,          /* org.freedesktop.DBus.Error.Spawn.ServiceNotFound */
  G_DBUS_ERROR_SPAWN_PERMISSIONS_INVALID,        /* org.freedesktop.DBus.Error.Spawn.PermissionsInvalid */
  G_DBUS_ERROR_SPAWN_FILE_INVALID,               /* org.freedesktop.DBus.Error.Spawn.FileInvalid */
  G_DBUS_ERROR_SPAWN_NO_MEMORY,                  /* org.freedesktop.DBus.Error.Spawn.NoMemory */
  G_DBUS_ERROR_UNIX_PROCESS_ID_UNKNOWN,          /* org.freedesktop.DBus.Error.UnixProcessIdUnknown */
  G_DBUS_ERROR_INVALID_SIGNATURE,                /* org.freedesktop.DBus.Error.InvalidSignature */
  G_DBUS_ERROR_INVALID_FILE_CONTENT,             /* org.freedesktop.DBus.Error.InvalidFileContent */
  G_DBUS_ERROR_SELINUX_SECURITY_CONTEXT_UNKNOWN, /* org.freedesktop.DBus.Error.SELinuxSecurityContextUnknown */
  G_DBUS_ERROR_ADT_AUDIT_DATA_UNKNOWN,           /* org.freedesktop.DBus.Error.AdtAuditDataUnknown */
  G_DBUS_ERROR_OBJECT_PATH_IN_USE                /* org.freedesktop.DBus.Error.ObjectPathInUse */
} GDBusError;

Error codes for the G_DBUS_ERROR error domain.

`G_DBUS_ERROR_FAILED`	A generic error; "something went wrong" - see the error message for more.
`G_DBUS_ERROR_NO_MEMORY`	There was not enough memory to complete an operation.
`G_DBUS_ERROR_SERVICE_UNKNOWN`	The bus doesn't know how to launch a service to supply the bus name you wanted.
`G_DBUS_ERROR_NAME_HAS_NO_OWNER`	The bus name you referenced doesn't exist (i.e. no application owns it).
`G_DBUS_ERROR_NO_REPLY`	No reply to a message expecting one, usually means a timeout occurred.
`G_DBUS_ERROR_IO_ERROR`	Something went wrong reading or writing to a socket, for example.
`G_DBUS_ERROR_BAD_ADDRESS`	A D-Bus bus address was malformed.
`G_DBUS_ERROR_NOT_SUPPORTED`	Requested operation isn't supported (like ENOSYS on UNIX).
`G_DBUS_ERROR_LIMITS_EXCEEDED`	Some limited resource is exhausted.
`G_DBUS_ERROR_ACCESS_DENIED`	Security restrictions don't allow doing what you're trying to do.
`G_DBUS_ERROR_AUTH_FAILED`	Authentication didn't work.
`G_DBUS_ERROR_NO_SERVER`	Unable to connect to server (probably caused by ECONNREFUSED on a socket).
`G_DBUS_ERROR_TIMEOUT`	Certain timeout errors, possibly ETIMEDOUT on a socket. Note that `G_DBUS_ERROR_NO_REPLY` is used for message reply timeouts. Warning: this is confusingly-named given that `G_DBUS_ERROR_TIMED_OUT` also exists. We can't fix it for compatibility reasons so just be careful.
`G_DBUS_ERROR_NO_NETWORK`	No network access (probably ENETUNREACH on a socket).
`G_DBUS_ERROR_ADDRESS_IN_USE`	Can't bind a socket since its address is in use (i.e. EADDRINUSE).
`G_DBUS_ERROR_DISCONNECTED`	The connection is disconnected and you're trying to use it.
`G_DBUS_ERROR_INVALID_ARGS`	Invalid arguments passed to a method call.
`G_DBUS_ERROR_FILE_NOT_FOUND`	Missing file.
`G_DBUS_ERROR_FILE_EXISTS`	Existing file and the operation you're using does not silently overwrite.
`G_DBUS_ERROR_UNKNOWN_METHOD`	Method name you invoked isn't known by the object you invoked it on.
`G_DBUS_ERROR_TIMED_OUT`	Certain timeout errors, e.g. while starting a service. Warning: this is confusingly-named given that `G_DBUS_ERROR_TIMEOUT` also exists. We can't fix it for compatibility reasons so just be careful.
`G_DBUS_ERROR_MATCH_RULE_NOT_FOUND`	Tried to remove or modify a match rule that didn't exist.
`G_DBUS_ERROR_MATCH_RULE_INVALID`	The match rule isn't syntactically valid.
`G_DBUS_ERROR_SPAWN_EXEC_FAILED`	While starting a new process, the `exec()` call failed.
`G_DBUS_ERROR_SPAWN_FORK_FAILED`	While starting a new process, the `fork()` call failed.
`G_DBUS_ERROR_SPAWN_CHILD_EXITED`	While starting a new process, the child exited with a status code.
`G_DBUS_ERROR_SPAWN_CHILD_SIGNALED`	While starting a new process, the child exited on a signal.
`G_DBUS_ERROR_SPAWN_FAILED`	While starting a new process, something went wrong.
`G_DBUS_ERROR_SPAWN_SETUP_FAILED`	We failed to setup the environment correctly.
`G_DBUS_ERROR_SPAWN_CONFIG_INVALID`	We failed to setup the config parser correctly.
`G_DBUS_ERROR_SPAWN_SERVICE_INVALID`	Bus name was not valid.
`G_DBUS_ERROR_SPAWN_SERVICE_NOT_FOUND`	Service file not found in system-services directory.
`G_DBUS_ERROR_SPAWN_PERMISSIONS_INVALID`	Permissions are incorrect on the setuid helper.
`G_DBUS_ERROR_SPAWN_FILE_INVALID`	Service file invalid (Name, User or Exec missing).
`G_DBUS_ERROR_SPAWN_NO_MEMORY`	Tried to get a UNIX process ID and it wasn't available.
`G_DBUS_ERROR_UNIX_PROCESS_ID_UNKNOWN`	Tried to get a UNIX process ID and it wasn't available.
`G_DBUS_ERROR_INVALID_SIGNATURE`	A type signature is not valid.
`G_DBUS_ERROR_INVALID_FILE_CONTENT`	A file contains invalid syntax or is otherwise broken.
`G_DBUS_ERROR_SELINUX_SECURITY_CONTEXT_UNKNOWN`	Asked for SELinux security context and it wasn't available.
`G_DBUS_ERROR_ADT_AUDIT_DATA_UNKNOWN`	Asked for ADT audit data and it wasn't available.
`G_DBUS_ERROR_OBJECT_PATH_IN_USE`	There's already an object with the requested object path.

Since 2.26

G_DBUS_ERROR

#define G_DBUS_ERROR g_dbus_error_quark()

Error domain for errors generated by a remote message bus. Errors in this domain will be from the GDBusError enumeration. See GError for more information on error domains.

Note that errors in this error domain is intended only for returning errors from a remote message bus process. Errors generated locally in-process by e.g. GDBusConnection is from the G_IO_ERROR domain.

Since 2.26

g_dbus_error_is_remote_error ()

gboolean            g_dbus_error_is_remote_error        (const GError *error);

Checks if error represents an error received via D-Bus from a remote peer. If so, use g_dbus_error_get_remote_error() to get the name of the error.

`error` :	A GError.
Returns :	`TRUE` if `error` represents an error from a remote peer, `FALSE` otherwise.

Since 2.26

g_dbus_error_get_remote_error ()

gchar *             g_dbus_error_get_remote_error       (const GError *error);

Gets the D-Bus error name used for error, if any.

This function is guaranteed to return a D-Bus error name for all GErrors returned from functions handling remote method calls (e.g. g_dbus_connection_call_finish()) unless g_dbus_error_strip_remote_error() has been used on error.

`error` :	A GError.
Returns :	An allocated string or `NULL` if the D-Bus error name could not be found. Free with `g_free()`.

Since 2.26

g_dbus_error_strip_remote_error ()

gboolean            g_dbus_error_strip_remote_error     (GError *error);

Looks for extra information in the error message used to recover the D-Bus error name and strips it if found. If stripped, the message field in error will correspond exactly to what was received on the wire.

This is typically used when presenting errors to the end user.

`error` :	A GError.
Returns :	`TRUE` if information was stripped, `FALSE` otherwise.

Since 2.26

GDBusErrorEntry

typedef struct {
  gint         error_code;
  const gchar *dbus_error_name;
} GDBusErrorEntry;

Struct used in g_dbus_error_register_error_domain().

gint `error_code`;	An error code.
const gchar *`dbus_error_name`;	The D-Bus error name to associate with `error_code`.

Since 2.26

g_dbus_error_register_error_domain ()

void                g_dbus_error_register_error_domain  (const gchar *error_domain_quark_name,
                                                         volatile gsize *quark_volatile,
                                                         const GDBusErrorEntry *entries,
                                                         guint num_entries);

Helper function for associating a GError error domain with D-Bus error names.

`error_domain_quark_name` :	The error domain name.
`quark_volatile` :	A pointer where to store the GQuark.
`entries` :	A pointer to `num_entries` GDBusErrorEntry struct items.
`num_entries` :	Number of items to register.

Since 2.26

g_dbus_error_register_error ()

gboolean            g_dbus_error_register_error         (GQuark error_domain,
                                                         gint error_code,
                                                         const gchar *dbus_error_name);

Creates an association to map between dbus_error_name and GErrors specified by error_domain and error_code.

This is typically done in the routine that returns the GQuark for an error domain.

`error_domain` :	A GQuark for a error domain.
`error_code` :	An error code.
`dbus_error_name` :	A D-Bus error name.
Returns :	`TRUE` if the association was created, `FALSE` if it already exists.

Since 2.26

g_dbus_error_unregister_error ()

gboolean            g_dbus_error_unregister_error       (GQuark error_domain,
                                                         gint error_code,
                                                         const gchar *dbus_error_name);

Destroys an association previously set up with g_dbus_error_register_error().

`error_domain` :	A GQuark for a error domain.
`error_code` :	An error code.
`dbus_error_name` :	A D-Bus error name.
Returns :	`TRUE` if the association was destroyed, `FALSE` if it wasn't found.

Since 2.26

g_dbus_error_new_for_dbus_error ()

GError *            g_dbus_error_new_for_dbus_error     (const gchar *dbus_error_name,
                                                         const gchar *dbus_error_message);

Creates a GError based on the contents of dbus_error_name and dbus_error_message.

Errors registered with g_dbus_error_register_error() will be looked up using dbus_error_name and if a match is found, the error domain and code is used. Applications can use g_dbus_error_get_remote_error() to recover dbus_error_name.

If a match against a registered error is not found and the D-Bus error name is in a form as returned by g_dbus_error_encode_gerror() the error domain and code encoded in the name is used to create the GError. Also, dbus_error_name is added to the error message such that it can be recovered with g_dbus_error_get_remote_error().

Otherwise, a GError with the error code G_IO_ERROR_DBUS_ERROR in the G_IO_ERROR error domain is returned. Also, dbus_error_name is added to the error message such that it can be recovered with g_dbus_error_get_remote_error().

In all three cases, dbus_error_name can always be recovered from the returned GError using the g_dbus_error_get_remote_error() function (unless g_dbus_error_strip_remote_error() hasn't been used on the returned error).

This function is typically only used in object mappings to prepare GError instances for applications. Regular applications should not use it.

`dbus_error_name` :	D-Bus error name.
`dbus_error_message` :	D-Bus error message.
Returns :	An allocated GError. Free with `g_error_free()`.

Since 2.26

g_dbus_error_set_dbus_error ()

void                g_dbus_error_set_dbus_error         (GError **error,
                                                         const gchar *dbus_error_name,
                                                         const gchar *dbus_error_message,
                                                         const gchar *format,
                                                         ...);

Does nothing if error is NULL. Otherwise sets *error to a new GError created with g_dbus_error_new_for_dbus_error() with dbus_error_message prepend with format (unless NULL).

`error` :	A pointer to a GError or `NULL`.
`dbus_error_name` :	D-Bus error name.
`dbus_error_message` :	D-Bus error message.
`format` :	printf()-style format to prepend to `dbus_error_message` or `NULL`.
`...` :	Arguments for `format`.

Since 2.26

g_dbus_error_set_dbus_error_valist ()

void                g_dbus_error_set_dbus_error_valist  (GError **error,
                                                         const gchar *dbus_error_name,
                                                         const gchar *dbus_error_message,
                                                         const gchar *format,
                                                         va_list var_args);

Like g_dbus_error_set_dbus_error() but intended for language bindings.

`error` :	A pointer to a GError or `NULL`.
`dbus_error_name` :	D-Bus error name.
`dbus_error_message` :	D-Bus error message.
`format` :	printf()-style format to prepend to `dbus_error_message` or `NULL`.
`var_args` :	Arguments for `format`.

Since 2.26

g_dbus_error_encode_gerror ()

gchar *             g_dbus_error_encode_gerror          (const GError *error);

Creates a D-Bus error name to use for error. If error matches a registered error (cf. g_dbus_error_register_error()), the corresponding D-Bus error name will be returned.

Otherwise the a name of the form org.gtk.GDBus.UnmappedGError.Quark._ESCAPED_QUARK_NAME.Code_ERROR_CODE will be used. This allows other GDBus applications to map the error on the wire back to a GError using g_dbus_error_new_for_dbus_error().

This function is typically only used in object mappings to put a GError on the wire. Regular applications should not use it.

`error` :	A GError.
Returns :	A D-Bus error name (never `NULL`). Free with `g_free()`.

Since 2.26

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