Tribblix: manual page: scf_transaction

SCF_TRANSACTION_CREATE(3SCF)
Service Configuration Facility Library Functions

NAME

scf_transaction_create, scf_transaction_handle,
scf_transaction_reset, scf_transaction_reset_all,
scf_transaction_destroy, scf_transaction_destroy_children,
scf_transaction_start, scf_transaction_property_delete,
scf_transaction_property_new, scf_transaction_property_change,
scf_transaction_property_change_type, scf_transaction_commit - create
and manipulate transaction in the Service Configuration Facility

SYNOPSIS

cc [ flag... ] file... -lscf [ library... ]
#include <libscf.h>

scf_transaction_t *scf_transaction_create(scf_handle_t *handle);

scf_handle_t *scf_transaction_handle(scf_transaction_t *tran);

void scf_transaction_reset(scf_transaction_t *tran);

void scf_transaction_reset_all(scf_transaction_t *tran);

void scf_transaction_destroy(scf_transaction_t *tran);

void scf_transaction_destroy_children(scf_transaction_t *tran);

int scf_transaction_start(scf_transaction_t *tran,
scf_propertygroup_t *pg);

int scf_transaction_property_delete(scf_transaction_t *tran,
scf_transaction_entry_t *entry, const char *prop_name);

int scf_transaction_property_new(scf_transaction_t *tran,
scf_transaction_entry_t *entry, const char *prop_name,
scf_type_t type);

int scf_transaction_property_change(scf_transaction_t *tran,
scf_transaction_entry_t *entry, const char *prop_name,
scf_type_t type);

int scf_transaction_property_change_type(
scf_transaction_t *tran, scf_transaction_entry_t *entry,
const char *prop_name, scf_type_t type);

int scf_transaction_commit(scf_transaction_t *tran);

DESCRIPTION

Transactions are the mechanism for changing property groups. They act
atomically, whereby either all of the updates occur or none of them
do. An scf_transaction_t is always in one of the following states:

reset
The initial state. A successful return of
scf_transaction_start() moves the transaction to the
started state.

started
The transaction has started. The
scf_transaction_property_delete(),
scf_transaction_property_new(),
scf_transaction_property_change(), and
scf_transaction_property_change_type() functions can be
used to set up changes to properties. The
scf_transaction_reset() and scf_transaction_reset_all()
functions return the transaction to the reset state.

committed
A call to scf_transaction_commit() (whether or not it is
successful) moves the transaction to the committed
state. Modifying, resetting, or destroying the entries
and values associated with a transaction will move it to
the invalid state.

invalid
The scf_transaction_reset() and
scf_transaction_reset_all() functions return the
transaction to the reset state.

The scf_transaction_create() function allocates and initializes an
scf_transaction_t bound to handle. The scf_transaction_destroy()
function resets, destroys, and frees tran. If there are any entries
associated with the transaction, scf_transaction_destroy() also
effects a call to scf_transaction_reset(). The
scf_transaction_destroy_children() function resets, destroys, and
frees all entries and values associated the transaction.

The scf_transaction_handle() function gets the handle to which tran
is bound.

The scf_transaction_start() function sets up the transaction to
modify the property group to which pg is set. The time reference used
by pg becomes the basis of the transaction. The transaction fails if
the property group has been modified since the last update of pg at
the time when scf_transaction_commit() is called.

The scf_transaction_property_delete(),
scf_transaction_property_new(), scf_transaction_property_change(),
and scf_transaction_property_change_type() functions add a new
transaction entry to the transaction. Each property the transaction
affects must have a unique scf_transaction_entry_t. Each
scf_transaction_entry_t can be associated with only a single
transaction at a time. These functions all fail if the transaction is
not in the started state, prop_name is not a valid property name, or
entry is already associated with a transaction. These functions
affect commit and failure as follows:

scf_transaction_property_delete()

This function deletes the property prop_name in the property
group. It fails if prop_name does not name a property in the
property group.

scf_transaction_property_new()

This function adds a new property prop_name to the property group
with a value list of type type. It fails if prop_name names an
existing property in the property group.

scf_transaction_property_change()

This function changes the value list for an existing property
prop_name in the property group. It fails if prop_name does not
name an existing property in the property group or names an
existing property with a different type.

scf_transaction_property_change_type()

This function changes the value list and type for an existing
property prop_name in the property group. It fails if prop_name
does not name an existing property in the property group.

If the function call is successful, entry remains active in the
transaction until scf_transaction_destroy(), scf_transaction_reset(),
or scf_transaction_reset_all() is called. The
scf_entry_add_value(3SCF) manual page provides information for
setting up the value list for entries that are not associated with
scf_transaction_property_delete(). Resetting or destroying an entry
or value active in a transaction will move it into the invalid state.

The scf_transaction_commit() function attempts to commit tran.

The scf_transaction_reset() function returns the transaction to the
reset state and releases all of the transaction entries that were
added.

The scf_transaction_reset_all() function returns the transaction to
the reset state, releases all of the transaction entries, and calls
scf_value_reset(3SCF) on all values associated with the entries.

RETURN VALUES

Upon successful completion, scf_transaction_create() returns a new
scf_transaction_t. Otherwise, it returns NULL.

Upon successful completion, scf_transaction_handle() returns the
handle associated with the transaction. Otherwise, it returns NULL.

Upon successful completion, scf_transaction_start(),
scf_transaction_property_delete(), scf_transaction_property_new(),
scf_transaction_property_change(), and
scf_transaction_property_change_type() return 0. Otherwise, they
return -1.

The scf_transaction_commit() function returns 1 upon successful
commit, 0 if the property group set in scf_transaction_start() is not
the most recent, and -1 on failure.

ERRORS

The scf_transaction_create() function will fail if:

SCF_ERROR_INVALID_ARGUMENT
The value of the handle argument is
NULL.

SCF_ERROR_NO_MEMORY
There is not enough memory to allocate
an scf_transaction_t.

SCF_ERROR_NO_RESOURCES
The server does not have adequate
resources for a new transaction handle.

The scf_transaction_handle() function will fail if:

SCF_ERROR_HANDLE_DESTROYED
The handle associated with tran has
been destroyed.

The scf_transaction_start() function will fail if:

SCF_ERROR_BACKEND_ACCESS

The repository backend refused the modification.

SCF_ERROR_BACKEND_READONLY

The repository backend refused modification because it is read-
only.

SCF_ERROR_CONNECTION_BROKEN

The connection to the repository was lost.

SCF_ERROR_DELETED

The property group has been deleted.

SCF_ERROR_HANDLE_MISMATCH

The transaction and property group are not derived from the same
handle.

SCF_ERROR_IN_USE

The transaction is not in the reset state. The
scf_transaction_reset() and scf_transaction_reset_all() functions
can be used to return the transaction to the reset state.

SCF_ERROR_NO_RESOURCES

The server does not have the resources to complete the request.

SCF_ERROR_NOT_BOUND

The handle was never bound or has been unbound.

SCF_ERROR_NOT_SET

The property group specified by pg is not set.

SCF_ERROR_PERMISSION_DENIED

The user does not have sufficient privileges to modify the
property group.

The scf_transaction_property_delete(),
scf_transaction_property_new(), scf_transaction_property_change(),
and scf_transaction_property_change_type() functions will fail if:

SCF_ERROR_BACKEND_ACCESS

The storage mechanism that the repository server
(svc.configd(8)) chose for the operation denied access.

SCF_ERROR_CONNECTION_BROKEN

The connection to the repository was lost.

SCF_ERROR_DELETED

The property group the transaction is changing has been deleted.

SCF_ERROR_HANDLE_MISMATCH

The transaction and entry are not derived from the same handle.

SCF_ERROR_IN_USE

The property already has an entry in the transaction.

SCF_ERROR_INTERNAL

An internal error occurred.

SCF_ERROR_INVALID_ARGUMENT

The prop_name argument is not a valid property name.

SCF_ERROR_NO_RESOURCES

The server does not have the resources to complete the request.

SCF_ERROR_NOT_BOUND

The handle is not bound.

SCF_ERROR_NOT_SET

The transaction has not been started.

SCF_ERROR_TYPE_MISMATCH

The tran argument is not of a type compatible with type.

The scf_transaction_property_delete(),
scf_transaction_property_change(), and
scf_transaction_property_change_type() functions will fail if:

SCF_ERROR_EXISTS
The object already exists.

SCF_ERROR_NOT_FOUND
The property group does not contain a property
named prop_name.

The scf_transaction_property_new() ,
scf_transaction_property_change(), and
scf_transaction_property_change_type() functions will fail if:

SCF_ERROR_INVALID_ARGUMENT
The prop_name argument is not not a
valid property name, or the type
argument is an invalid type.

The scf_transaction_property_new() function will fail if:

SCF_ERROR_EXISTS
The property group already contains a property
named prop_name.

SCF_ERROR_NOT_FOUND
Nothing of that name was found.

The scf_transaction_property_change() function will fail if:

SCF_ERROR_TYPE_MISMATCH
The property prop_name is not of type
type.

The scf_transaction_commit() function will fail if:

SCF_ERROR_BACKEND_READONLY

The repository backend is read-only.

SCF_ERROR_BACKEND_ACCESS

The repository backend refused the modification.

SCF_ERROR_NOT_BOUND

The handle is not bound.

SCF_ERROR_CONNECTION_BROKEN

The connection to the repository was lost.

SCF_ERROR_INVALID_ARGUMENT

The transaction is in an invalid state.

SCF_ERROR_DELETED

The property group the transaction is acting on has been deleted.

SCF_ERROR_NOT_SET

The transaction has not been started.

SCF_ERROR_PERMISSION_DENIED

The user does not have sufficient privileges to modify the
property group.

SCF_ERROR_NO_RESOURCES

The server does not have sufficient resources to commit the
transaction.

The scf_error(3SCF) function can be used to retrieve the error value.

EXAMPLES

Example 1: Set an existing boolean value to true.

tx = scf_transaction_create(handle);
e1 = scf_entry_create(handle);
v1 = scf_value_create(handle);

do {
if (scf_pg_update(pg) == -1)
goto fail;
if (scf_transaction_start(tx, pg) == -1)
goto fail;

/* set up transaction entries */
if (scf_transaction_property_change(tx, e1, "property",
SCF_TYPE_BOOLEAN) == -1) {
scf_transaction_reset(tx);
goto fail;
}
scf_value_set_boolean(v1, 1);
scf_entry_add_value(e1, v1);

result = scf_transaction_commit(tx);

scf_transaction_reset(tx);
} while (result == 0);

if (result < 0)
goto fail;

/* success */

cleanup:
scf_transaction_destroy(tx);
scf_entry_destroy(e1);
scf_value_destroy(v1);

ATTRIBUTES