Re: [libvirt] [PATCHv4 3/7] interface: implement public APIs for libvirt transactional network changes

From: Michal Privoznik <mprivozn(a)redhat.com&gt; change from previous version: modified to be the same code style as other libvirt public API functions. --- src/libvirt.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 180 insertions(+), 2 deletions(-) diff --git a/src/libvirt.c b/src/libvirt.c index ff16c48..f850665 100644 --- a/src/libvirt.c +++ b/src/libvirt.c @@ -8143,7 +8143,18 @@ error: * @xml: the XML description for the interface, preferably in UTF-8 * @flags: and OR'ed set of extraction flags, not used yet * - * Define an interface (or modify existing interface configuration) + + * Define an interface (or modify existing interface configuration). + * + * Normally this change in the interface configuration is immediately + * permanent/persistent, but if virInterfaceChangeBegin() has been + * previously called (i.e. if an interface config transaction is + * open), the new interface definition will only become permanent if + * virInterfaceChangeCommit() is called prior to the next reboot of + * the system running libvirtd. Prior to that time, it can be + * explicitly removed using virInterfaceChangeRollback(), or will be + * automatically removed during the next reboot of the system running + * libvirtd. * * Returns NULL in case of error, a pointer to the interface otherwise */ @@ -8190,6 +8201,16 @@ error: * Undefine an interface, ie remove it from the config. * This does not free the associated virInterfacePtr object. * + * Normally this change in the interface configuration is + * permanent/persistent, but if virInterfaceChangeBegin() has been + * previously called (i.e. if an interface config transaction is + * open), the removal of the interface definition will only become + * permanent if virInterfaceChangeCommit() is called prior to the next + * reboot of the system running libvirtd. Prior to that time, the + * definition can be explicitly restored using + * virInterfaceChangeRollback(), or will be automatically restored + * during the next reboot of the system running libvirtd. + * * Returns 0 in case of success, -1 in case of error */ int @@ -8230,8 +8251,13 @@ error: * @iface: pointer to a defined interface * @flags: and OR'ed set of extraction flags, not used yet * - * Activate an interface (ie call "ifup") + * Activate an interface (i.e. call "ifup"). * + * If there was an open network config transaction at the time this + * interface was defined (that is, if virInterfaceChangeBegin() had + * been called), the interface will be brought back down (and then + * undefined) if virInterfaceChangeRollback() is called. +p * * Returns 0 in case of success, -1 in case of error */ int @@ -8277,6 +8303,13 @@ error: * This does not remove the interface from the config, and * does not free the associated virInterfacePtr object. * + + * If there is an open network config transaction at the time this + * interface is destroyed (that is, if virInterfaceChangeBegin() had + * been called), and if the interface is later undefined and then + * virInterfaceChangeRollback() is called, the restoral of the + * interface definition will also bring the interface back up. + * * Returns 0 in case of success and -1 in case of failure. */ int @@ -8374,6 +8407,151 @@ virInterfaceFree(virInterfacePtr iface) return 0; } +/** + * virInterfaceChangeBegin: + * @conn: pointer to hypervisor connection + * @flags: flags, not used yet + * + * This functions creates a restore point to which one can return + * later by calling virInterfaceChangeRollback(). This function should + * be called before any transaction with interface configuration. + * Once knowing, new configuration works, it can be commited via + * virInterfaceChangeCommit(), which frees the restore point. + * + * If virInterfaceChangeBegin() is called when a transaction is + * already opened, this function will fail, and a + * VIR_ERR_INVALID_OPERATION will be logged. + * + * Returns 0 in case of success and -1 in case of failure. + */ +int +virInterfaceChangeBegin(virConnectPtr conn, unsigned int flags) +{ + VIR_DEBUG("conn=%p, flags=%d", conn, flags); + + virResetLastError(); + + if (!VIR_IS_CONNECT(conn)) { + virLibConnError(VIR_ERR_INVALID_CONN, __FUNCTION__); + virDispatchError(NULL); + return -1; + } + + if (conn->flags & VIR_CONNECT_RO) { + virLibInterfaceError(VIR_ERR_OPERATION_DENIED, __FUNCTION__); + goto error; + } + + if (conn->interfaceDriver && conn->interfaceDriver->interfaceChangeBegin) { + int ret; + ret = conn->interfaceDriver->interfaceChangeBegin(conn, flags); + if (ret < 0) + goto error; + return ret; + } + + virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__); + +error: + virDispatchError(conn); + return -1; +} + +/** + * virInterfaceChangeCommit: + * @conn: pointer to hypervisor connection + * @flags: flags, not used yet + * + * This commits the changes made to interfaces and frees the restore point + * created by virInterfaceChangeBegin(). + * + * If virInterfaceChangeCommit() is called when a transaction is not + * opened, this function will fail, and a VIR_ERR_INVALID_OPERATION + * will be logged. + * + * Returns 0 in case of success and -1 in case of failure. + */ +int +virInterfaceChangeCommit(virConnectPtr conn, unsigned int flags) +{ + VIR_DEBUG("conn=%p, flags=%d", conn, flags); + + virResetLastError(); + + if (!VIR_IS_CONNECT(conn)) { + virLibConnError(VIR_ERR_INVALID_CONN, __FUNCTION__); + virDispatchError(NULL); + return -1; + } + + if (conn->flags & VIR_CONNECT_RO) { + virLibInterfaceError(VIR_ERR_OPERATION_DENIED, __FUNCTION__); + goto error; + } + + if (conn->interfaceDriver && conn->interfaceDriver->interfaceChangeCommit) { + int ret; + ret = conn->interfaceDriver->interfaceChangeCommit(conn, flags); + if (ret < 0) + goto error; + return ret; + } + + virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__); + +error: + virDispatchError(conn); + return -1; +} + +/** + * virInterfaceChangeRollback: + * @conn: pointer to hypervisor connection + * @flags: flags, not used yet + * + * This cancels changes made to interfaces settings by restoring previous + * state created by virInterfaceChangeBegin(). + * + * If virInterfaceChangeRollback() is called when a transaction is not + * opened, this function will fail, and a VIR_ERR_INVALID_OPERATION + * will be logged. + * + * Returns 0 in case of success and -1 in case of failure. + */ +int +virInterfaceChangeRollback(virConnectPtr conn, unsigned int flags) +{ + VIR_DEBUG("conn=%p, flags=%d", conn, flags); + + virResetLastError(); + + if (!VIR_IS_CONNECT(conn)) { + virLibConnError(VIR_ERR_INVALID_CONN, __FUNCTION__); + virDispatchError(NULL); + return -1; + } + + if (conn->flags & VIR_CONNECT_RO) { + virLibInterfaceError(VIR_ERR_OPERATION_DENIED, __FUNCTION__); + goto error; + } + + if (conn->interfaceDriver && + conn->interfaceDriver->interfaceChangeRollback) { + int ret; + ret = conn->interfaceDriver->interfaceChangeRollback(conn, flags); + if (ret < 0) + goto error; + return ret; + } + + virLibConnError(VIR_ERR_NO_SUPPORT, __FUNCTION__); + +error: + virDispatchError(conn); + return -1; +} +