diff options
Diffstat (limited to 'lib/device/dev-ext.c')
| -rw-r--r-- | lib/device/dev-ext.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/lib/device/dev-ext.c b/lib/device/dev-ext.c new file mode 100644 index 0000000..15e9c2b --- /dev/null +++ b/lib/device/dev-ext.c @@ -0,0 +1,170 @@ +/* + * Copyright (C) 2014 Red Hat, Inc. All rights reserved. + * + * This file is part of LVM2. + * + * This copyrighted material is made available to anyone wishing to use, + * modify, copy, or redistribute it subject to the terms and conditions + * of the GNU Lesser General Public License v.2.1. + * + * You should have received a copy of the GNU Lesser General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "lib/misc/lib.h" +#include "lib/device/device.h" + +#ifdef UDEV_SYNC_SUPPORT +#include <libudev.h> +#endif + +struct ext_registry_item { + const char *name; + struct dev_ext *(* dev_ext_get) (struct device *dev); + int (*dev_ext_release) (struct device *dev); +}; + +#define EXT_REGISTER(id,name) [id] = { #name, &_dev_ext_get_ ## name, &_dev_ext_release_ ## name } + +/* + * DEV_EXT_NONE + */ +static struct dev_ext *_dev_ext_get_none(struct device *dev) +{ + dev->ext.handle = NULL; + return &dev->ext; +} + +static int _dev_ext_release_none(struct device *dev) +{ + dev->ext.handle = NULL; + return 1; +} + +/* + * DEV_EXT_UDEV + */ +static struct dev_ext *_dev_ext_get_udev(struct device *dev) +{ +#ifdef UDEV_SYNC_SUPPORT + struct udev *udev; + struct udev_device *udev_device; + + if (dev->ext.handle) + return &dev->ext; + + if (!(udev = udev_get_library_context())) + return_NULL; + + if (!(udev_device = udev_device_new_from_devnum(udev, 'b', dev->dev))) + return_NULL; + +#ifdef HAVE_LIBUDEV_UDEV_DEVICE_GET_IS_INITIALIZED + if (!udev_device_get_is_initialized(udev_device)) { + /* Timeout or some other udev db inconsistency! */ + log_error("Udev database has incomplete information about device %s.", dev_name(dev)); + return NULL; + } +#endif + + dev->ext.handle = (void *) udev_device; + return &dev->ext; +#else + return NULL; +#endif +} + +static int _dev_ext_release_udev(struct device *dev) +{ +#ifdef UDEV_SYNC_SUPPORT + if (!dev->ext.handle) + return 1; + + /* udev_device_unref can't fail - it has no return value */ + udev_device_unref((struct udev_device *) dev->ext.handle); + dev->ext.handle = NULL; + return 1; +#else + return 0; +#endif +} + +static struct ext_registry_item _ext_registry[DEV_EXT_NUM] = { + EXT_REGISTER(DEV_EXT_NONE, none), + EXT_REGISTER(DEV_EXT_UDEV, udev) +}; + +const char *dev_ext_name(struct device *dev) +{ + return _ext_registry[dev->ext.src].name; +} + +struct dev_ext *dev_ext_get(struct device *dev) +{ + struct dev_ext *ext; + void *handle_ptr; + + handle_ptr = dev->ext.handle; + + if (!(ext = _ext_registry[dev->ext.src].dev_ext_get(dev))) + log_error("%s: Failed to get external handle [%s].", + dev_name(dev), dev_ext_name(dev)); + else if (handle_ptr != dev->ext.handle) + log_debug_devs("%s: External handle [%s:%p] attached", dev_name(dev), + dev_ext_name(dev), dev->ext.handle); + + return ext; +} + +int dev_ext_release(struct device *dev) +{ + int r; + void *handle_ptr; + + if (!dev->ext.enabled || + !dev->ext.handle) + return 1; + + handle_ptr = dev->ext.handle; + + if (!(r = _ext_registry[dev->ext.src].dev_ext_release(dev))) + log_error("%s: Failed to release external handle [%s:%p]", + dev_name(dev), dev_ext_name(dev), dev->ext.handle); + else + log_debug_devs("%s: External handle [%s:%p] detached", + dev_name(dev), dev_ext_name(dev), handle_ptr); + + return r; +} + +int dev_ext_enable(struct device *dev, dev_ext_t src) +{ + if (dev->ext.enabled && (dev->ext.src != src) && !dev_ext_release(dev)) { + log_error("%s: Failed to enable external handle [%s].", + dev_name(dev), _ext_registry[src].name); + return 0; + } + + dev->ext.src = src; + dev->ext.enabled = 1; + + return 1; +} + +int dev_ext_disable(struct device *dev) +{ + if (!dev->ext.enabled) + return 1; + + if (!dev_ext_release(dev)) { + log_error("%s: Failed to disable external handle [%s].", + dev_name(dev), dev_ext_name(dev)); + return 0; + } + + dev->ext.enabled = 0; + dev->ext.src = DEV_EXT_NONE; + + return 1; +} |