parted-1.8.7/libparted/device.c - nest-learning-thermostat/5.1.6/parted - Git at Google

 /*
     libparted - a library for manipulating disk partitions
     Copyright (C) 1999 - 2001, 2005, 2007 Free Software Foundation, Inc.

     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.

     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with this program; if not, write to the Free Software
     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

 /** \file device.c */

 /**
  * \addtogroup PedDevice
  *
  * \brief Device access.
  *
  * When ped_device_probe_all() is called, libparted attempts to detect all
  * devices.  It constructs a list which can be accessed with
  * ped_device_get_next().
  *
  * If you want to use a device that isn't on the list, use
  * ped_device_get().  Also, there may be OS-specific constructors, for creating
  * devices from file descriptors, stores, etc.  For example,
  * ped_device_new_from_store().
  *
  * @{
  */

 #include <config.h>

 #include <parted/parted.h>
 #include <parted/debug.h>

 #include <limits.h>
 #include <unistd.h>
 #include <errno.h>

 static PedDevice*	devices; /* legal advice says: initialized to NULL,
 				    under section 6.7.8 part 10
 				    of ISO/EIC 9899:1999 */

 #ifndef HAVE_CANONICALIZE_FILE_NAME
 char *
 canonicalize_file_name (const char *name)
 {
 	char *	buf;
 	int	size;
 	char *	result;

 #ifdef PATH_MAX
 	size = PATH_MAX;
 #else
 	/* Bigger is better; realpath has no way todo bounds checking.  */
 	size = 4096;
 #endif

 	/* Just in case realpath does not NULL terminate the string
 	 * or it just fits in SIZE without a NULL terminator.  */
 	buf = calloc (size + 1, sizeof(char));
 	if (! buf) {
 		errno = ENOMEM;
 		return NULL;
 	}

 	result = realpath (name, buf);
 	if (! result)
 		free (buf);

 	return result;
 }
 #endif /* !HAVE_CANONICALIZE_FILE_NAME */

 static void
 _device_register (PedDevice* dev)
 {
 	PedDevice*	walk;
 	for (walk = devices; walk && walk->next; walk = walk->next);
 	if (walk)
 		walk->next = dev;
 	else
 		devices = dev;
 	dev->next = NULL;
 }

 static void
 _device_unregister (PedDevice* dev)
 {
 	PedDevice*	walk;
 	PedDevice*	last = NULL;

 	for (walk = devices; walk != NULL; last = walk, walk = walk->next) {
 		if (walk == dev) break;
 	}

 	if (last)
 		last->next = dev->next;
 	else
 		devices = dev->next;
 }

 /**
  * Returns the next device that was detected by ped_device_probe_all(), or
  * calls to ped_device_get_next().
  * If dev is NULL, returns the first device.
  *
  * \return NULL if dev is the last device.
  */
 PedDevice*
 ped_device_get_next (const PedDevice* dev)
 {
 	if (dev)
 		return dev->next;
 	else
 		return devices;
 }

 void
 _ped_device_probe (const char* path)
 {
 	PedDevice*	dev;

 	PED_ASSERT (path != NULL, return);

 	ped_exception_fetch_all ();
 	dev = ped_device_get (path);
 	if (!dev)
 		ped_exception_catch ();
 	ped_exception_leave_all ();
 }

 /**
  * Attempts to detect all devices.
  */
 void
 ped_device_probe_all ()
 {
 	ped_architecture->dev_ops->probe_all ();
 }

 /**
  * Close/free all devices.
  * Called by ped_done(), so you do not need to worry about it.
  */
 void
 ped_device_free_all ()
 {
 	while (devices)
 		ped_device_destroy (devices);
 }

 /**
  * Gets the device "name", where name is usually the block device, e.g.
  * /dev/sdb.  If the device wasn't detected with ped_device_probe_all(),
  * an attempt will be made to detect it again.  If it is found, it will
  * be added to the list.
  */
 PedDevice*
 ped_device_get (const char* path)
 {
 	PedDevice*	walk;
 	char*		normal_path;

 	PED_ASSERT (path != NULL, return NULL);
 	normal_path = canonicalize_file_name (path);
 	if (!normal_path)
 		/* Well, maybe it is just that the file does not exist.
 		 * Try it anyway.  */
 		normal_path = strdup (path);
 	if (!normal_path)
 		return NULL;

 	for (walk = devices; walk != NULL; walk = walk->next) {
 		if (!strcmp (walk->path, normal_path)) {
 			ped_free (normal_path);
 			return walk;
 		}
 	}

 	walk = ped_architecture->dev_ops->_new (normal_path);
 	ped_free (normal_path);
 	if (!walk)
 		return NULL;
 	_device_register (walk);
 	return walk;
 }

 /**
  * Destroys a device and removes it from the device list, and frees
  * all resources associated with the device (all resources allocated
  * when the device was created).
  */
 void
 ped_device_destroy (PedDevice* dev)
 {
 	_device_unregister (dev);

 	while (dev->open_count) {
 		if (!ped_device_close (dev))
 			break;
 	}

 	ped_architecture->dev_ops->destroy (dev);
 }

 void
 ped_device_cache_remove(PedDevice *dev)
 {
 	_device_unregister (dev);
 }

 int
 ped_device_is_busy (PedDevice* dev)
 {
 	return ped_architecture->dev_ops->is_busy (dev);
 }

 /**
  * Attempt to open a device to allow use of read, write and sync functions.
  *
  * The meaning of "open" is architecture-dependent.  Apart from requesting
  * access to the device from the operating system, it does things like flushing
  * caches.
  * \note May allocate resources.  Any resources allocated here will
  * be freed by a final ped_device_close().  (ped_device_open() may be
  * called multiple times -- it's a ref-count-like mechanism)
  *
  * \return zero on failure
  */
 int
 ped_device_open (PedDevice* dev)
 {
 	int	status;

 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);

 	if (dev->open_count)
 		status = ped_architecture->dev_ops->refresh_open (dev);
 	else
 		status = ped_architecture->dev_ops->open (dev);
 	if (status)
 		dev->open_count++;
 	return status;
 }

 /**
  * Close dev.
  * If this is the final close, then resources allocated by
  * ped_device_open() are freed.
  *
  * \return zero on failure
  */
 int
 ped_device_close (PedDevice* dev)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);
 	PED_ASSERT (dev->open_count > 0, return 0);

 	if (--dev->open_count)
 		return ped_architecture->dev_ops->refresh_close (dev);
 	else
 		return ped_architecture->dev_ops->close (dev);
 }

 /**
  * Begins external access mode.  External access mode allows you to
  * safely do IO on the device.  If a PedDevice is open, then you should
  * not do any IO on that device, e.g. by calling an external program
  * like e2fsck, unless you put it in external access mode.  You should
  * not use any libparted commands that do IO to a device, e.g.
  * ped_file_system_{open|resize|copy}, ped_disk_{read|write}), while
  * a device is in external access mode.
  * Also, you should not ped_device_close() a device, while it is
  * in external access mode.
  * Note: ped_device_begin_external_access_mode() does things like
  * tell the kernel to flush its caches.
  *
  * Close a device while pretending it is still open.
  * This is useful for temporarily suspending libparted access to the device
  * in order for an external program to access it.
  * (Running external programs while the device is open can cause cache
  * coherency problems.)
  *
  * In particular, this function keeps track of dev->open_count, so that
  * reference counting isn't screwed up.
  *
  * \return zero on failure.
  */
 int
 ped_device_begin_external_access (PedDevice* dev)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);

 	dev->external_mode = 1;
 	if (dev->open_count)
 		return ped_architecture->dev_ops->close (dev);
 	else
 		return 1;
 }

 /**
  * \brief Complementary function to ped_device_begin_external_access.
  *
  * \note does things like tell the kernel to flush the device's cache.
  *
  * \return zero on failure.
  */
 int
 ped_device_end_external_access (PedDevice* dev)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (dev->external_mode, return 0);

 	dev->external_mode = 0;
 	if (dev->open_count)
 		return ped_architecture->dev_ops->open (dev);
 	else
 		return 1;
 }

 /**
  * \internal Read count sectors from dev into buffer, beginning with sector
  * start.
  *
  * \return zero on failure.
  */
 int
 ped_device_read (const PedDevice* dev, void* buffer, PedSector start,
 		 PedSector count)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (buffer != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);
 	PED_ASSERT (dev->open_count > 0, return 0);

 	return (ped_architecture->dev_ops->read) (dev, buffer, start, count);
 }

 /**
  * \internal Write count sectors from buffer to dev, starting at sector
  * start.
  *
  * \return zero on failure.
  *
  * \sa PedDevice::sector_size
  * \sa PedDevice::phys_sector_size
  */
 int
 ped_device_write (PedDevice* dev, const void* buffer, PedSector start,
 		  PedSector count)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (buffer != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);
 	PED_ASSERT (dev->open_count > 0, return 0);

 	return (ped_architecture->dev_ops->write) (dev, buffer, start, count);
 }

 PedSector
 ped_device_check (PedDevice* dev, void* buffer, PedSector start,
 		  PedSector count)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);
 	PED_ASSERT (dev->open_count > 0, return 0);

 	return (ped_architecture->dev_ops->check) (dev, buffer, start, count);
 }

 /**
  * \internal Flushes all write-behind caches that might be holding up
  * writes.
  * It is slow because it guarantees cache coherency among all relevant caches.
  *
  * \return zero on failure
  */
 int
 ped_device_sync (PedDevice* dev)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);
 	PED_ASSERT (dev->open_count > 0, return 0);

 	return ped_architecture->dev_ops->sync (dev);
 }

 /**
  * \internal Flushes all write-behind caches that might be holding writes.
  * \warning Does NOT ensure cache coherency with other caches.
  * If you need cache coherency, use ped_device_sync() instead.
  *
  * \return zero on failure
  */
 int
 ped_device_sync_fast (PedDevice* dev)
 {
 	PED_ASSERT (dev != NULL, return 0);
 	PED_ASSERT (!dev->external_mode, return 0);
 	PED_ASSERT (dev->open_count > 0, return 0);

 	return ped_architecture->dev_ops->sync_fast (dev);
 }

 /**
  * Get a constraint that represents hardware requirements on alignment and
  * geometry.
  * This is, for example, important for media that have a physical sector
  * size that is a multiple of the logical sector size.
  *
  * \warning This function is experimental for physical sector sizes not equal to
  *          2^9.
  */
 PedConstraint*
 ped_device_get_constraint (PedDevice* dev)
 {
         int multiplier = dev->phys_sector_size / dev->sector_size;

         PedAlignment* start_align = ped_alignment_new (multiplier, multiplier);

         PedConstraint* c = ped_constraint_new (
                                 start_align, ped_alignment_any,
                                 ped_geometry_new (dev, 0, dev->length),
                                 ped_geometry_new (dev, 0, dev->length),
                                 1, dev->length);

         return c;
 }

 /** @} */
	/*
	libparted - a library for manipulating disk partitions
	Copyright (C) 1999 - 2001, 2005, 2007 Free Software Foundation, Inc.

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
	*/

	/** \file device.c */

	/**
	* \addtogroup PedDevice
	*
	* \brief Device access.
	*
	* When ped_device_probe_all() is called, libparted attempts to detect all
	* devices. It constructs a list which can be accessed with
	* ped_device_get_next().
	*
	* If you want to use a device that isn't on the list, use
	* ped_device_get(). Also, there may be OS-specific constructors, for creating
	* devices from file descriptors, stores, etc. For example,
	* ped_device_new_from_store().
	*
	* @{
	*/

	#include <config.h>

	#include <parted/parted.h>
	#include <parted/debug.h>

	#include <limits.h>
	#include <unistd.h>
	#include <errno.h>

	static PedDevice* devices; /* legal advice says: initialized to NULL,
	under section 6.7.8 part 10
	of ISO/EIC 9899:1999 */

	#ifndef HAVE_CANONICALIZE_FILE_NAME
	char *
	canonicalize_file_name (const char *name)
	{
	char * buf;
	int size;
	char * result;

	#ifdef PATH_MAX
	size = PATH_MAX;
	#else
	/* Bigger is better; realpath has no way todo bounds checking. */
	size = 4096;
	#endif

	/* Just in case realpath does not NULL terminate the string
	* or it just fits in SIZE without a NULL terminator. */
	buf = calloc (size + 1, sizeof(char));
	if (! buf) {
	errno = ENOMEM;
	return NULL;
	}

	result = realpath (name, buf);
	if (! result)
	free (buf);

	return result;
	}
	#endif /* !HAVE_CANONICALIZE_FILE_NAME */

	static void
	_device_register (PedDevice* dev)
	{
	PedDevice* walk;
	for (walk = devices; walk && walk->next; walk = walk->next);
	if (walk)
	walk->next = dev;
	else
	devices = dev;
	dev->next = NULL;
	}

	static void
	_device_unregister (PedDevice* dev)
	{
	PedDevice* walk;
	PedDevice* last = NULL;

	for (walk = devices; walk != NULL; last = walk, walk = walk->next) {
	if (walk == dev) break;
	}

	if (last)
	last->next = dev->next;
	else
	devices = dev->next;
	}

	/**
	* Returns the next device that was detected by ped_device_probe_all(), or
	* calls to ped_device_get_next().
	* If dev is NULL, returns the first device.
	*
	* \return NULL if dev is the last device.
	*/
	PedDevice*
	ped_device_get_next (const PedDevice* dev)
	{
	if (dev)
	return dev->next;
	else
	return devices;
	}

	void
	_ped_device_probe (const char* path)
	{
	PedDevice* dev;

	PED_ASSERT (path != NULL, return);

	ped_exception_fetch_all ();
	dev = ped_device_get (path);
	if (!dev)
	ped_exception_catch ();
	ped_exception_leave_all ();
	}

	/**
	* Attempts to detect all devices.
	*/
	void
	ped_device_probe_all ()
	{
	ped_architecture->dev_ops->probe_all ();
	}

	/**
	* Close/free all devices.
	* Called by ped_done(), so you do not need to worry about it.
	*/
	void
	ped_device_free_all ()
	{
	while (devices)
	ped_device_destroy (devices);
	}

	/**
	* Gets the device "name", where name is usually the block device, e.g.
	* /dev/sdb. If the device wasn't detected with ped_device_probe_all(),
	* an attempt will be made to detect it again. If it is found, it will
	* be added to the list.
	*/
	PedDevice*
	ped_device_get (const char* path)
	{
	PedDevice* walk;
	char* normal_path;

	PED_ASSERT (path != NULL, return NULL);
	normal_path = canonicalize_file_name (path);
	if (!normal_path)
	/* Well, maybe it is just that the file does not exist.
	* Try it anyway. */
	normal_path = strdup (path);
	if (!normal_path)
	return NULL;

	for (walk = devices; walk != NULL; walk = walk->next) {
	if (!strcmp (walk->path, normal_path)) {
	ped_free (normal_path);
	return walk;
	}
	}

	walk = ped_architecture->dev_ops->_new (normal_path);
	ped_free (normal_path);
	if (!walk)
	return NULL;
	_device_register (walk);
	return walk;
	}

	/**
	* Destroys a device and removes it from the device list, and frees
	* all resources associated with the device (all resources allocated
	* when the device was created).
	*/
	void
	ped_device_destroy (PedDevice* dev)
	{
	_device_unregister (dev);

	while (dev->open_count) {
	if (!ped_device_close (dev))
	break;
	}

	ped_architecture->dev_ops->destroy (dev);
	}

	void
	ped_device_cache_remove(PedDevice *dev)
	{
	_device_unregister (dev);
	}

	int
	ped_device_is_busy (PedDevice* dev)
	{
	return ped_architecture->dev_ops->is_busy (dev);
	}

	/**
	* Attempt to open a device to allow use of read, write and sync functions.
	*
	* The meaning of "open" is architecture-dependent. Apart from requesting
	* access to the device from the operating system, it does things like flushing
	* caches.
	* \note May allocate resources. Any resources allocated here will
	* be freed by a final ped_device_close(). (ped_device_open() may be
	* called multiple times -- it's a ref-count-like mechanism)
	*
	* \return zero on failure
	*/
	int
	ped_device_open (PedDevice* dev)
	{
	int status;

	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);

	if (dev->open_count)
	status = ped_architecture->dev_ops->refresh_open (dev);
	else
	status = ped_architecture->dev_ops->open (dev);
	if (status)
	dev->open_count++;
	return status;
	}

	/**
	* Close dev.
	* If this is the final close, then resources allocated by
	* ped_device_open() are freed.
	*
	* \return zero on failure
	*/
	int
	ped_device_close (PedDevice* dev)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);
	PED_ASSERT (dev->open_count > 0, return 0);

	if (--dev->open_count)
	return ped_architecture->dev_ops->refresh_close (dev);
	else
	return ped_architecture->dev_ops->close (dev);
	}

	/**
	* Begins external access mode. External access mode allows you to
	* safely do IO on the device. If a PedDevice is open, then you should
	* not do any IO on that device, e.g. by calling an external program
	* like e2fsck, unless you put it in external access mode. You should
	* not use any libparted commands that do IO to a device, e.g.
	* ped_file_system_{open\|resize\|copy}, ped_disk_{read\|write}), while
	* a device is in external access mode.
	* Also, you should not ped_device_close() a device, while it is
	* in external access mode.
	* Note: ped_device_begin_external_access_mode() does things like
	* tell the kernel to flush its caches.
	*
	* Close a device while pretending it is still open.
	* This is useful for temporarily suspending libparted access to the device
	* in order for an external program to access it.
	* (Running external programs while the device is open can cause cache
	* coherency problems.)
	*
	* In particular, this function keeps track of dev->open_count, so that
	* reference counting isn't screwed up.
	*
	* \return zero on failure.
	*/
	int
	ped_device_begin_external_access (PedDevice* dev)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);

	dev->external_mode = 1;
	if (dev->open_count)
	return ped_architecture->dev_ops->close (dev);
	else
	return 1;
	}

	/**
	* \brief Complementary function to ped_device_begin_external_access.
	*
	* \note does things like tell the kernel to flush the device's cache.
	*
	* \return zero on failure.
	*/
	int
	ped_device_end_external_access (PedDevice* dev)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (dev->external_mode, return 0);

	dev->external_mode = 0;
	if (dev->open_count)
	return ped_architecture->dev_ops->open (dev);
	else
	return 1;
	}

	/**
	* \internal Read count sectors from dev into buffer, beginning with sector
	* start.
	*
	* \return zero on failure.
	*/
	int
	ped_device_read (const PedDevice* dev, void* buffer, PedSector start,
	PedSector count)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (buffer != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);
	PED_ASSERT (dev->open_count > 0, return 0);

	return (ped_architecture->dev_ops->read) (dev, buffer, start, count);
	}

	/**
	* \internal Write count sectors from buffer to dev, starting at sector
	* start.
	*
	* \return zero on failure.
	*
	* \sa PedDevice::sector_size
	* \sa PedDevice::phys_sector_size
	*/
	int
	ped_device_write (PedDevice* dev, const void* buffer, PedSector start,
	PedSector count)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (buffer != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);
	PED_ASSERT (dev->open_count > 0, return 0);

	return (ped_architecture->dev_ops->write) (dev, buffer, start, count);
	}

	PedSector
	ped_device_check (PedDevice* dev, void* buffer, PedSector start,
	PedSector count)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);
	PED_ASSERT (dev->open_count > 0, return 0);

	return (ped_architecture->dev_ops->check) (dev, buffer, start, count);
	}

	/**
	* \internal Flushes all write-behind caches that might be holding up
	* writes.
	* It is slow because it guarantees cache coherency among all relevant caches.
	*
	* \return zero on failure
	*/
	int
	ped_device_sync (PedDevice* dev)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);
	PED_ASSERT (dev->open_count > 0, return 0);

	return ped_architecture->dev_ops->sync (dev);
	}

	/**
	* \internal Flushes all write-behind caches that might be holding writes.
	* \warning Does NOT ensure cache coherency with other caches.
	* If you need cache coherency, use ped_device_sync() instead.
	*
	* \return zero on failure
	*/
	int
	ped_device_sync_fast (PedDevice* dev)
	{
	PED_ASSERT (dev != NULL, return 0);
	PED_ASSERT (!dev->external_mode, return 0);
	PED_ASSERT (dev->open_count > 0, return 0);

	return ped_architecture->dev_ops->sync_fast (dev);
	}

	/**
	* Get a constraint that represents hardware requirements on alignment and
	* geometry.
	* This is, for example, important for media that have a physical sector
	* size that is a multiple of the logical sector size.
	*
	* \warning This function is experimental for physical sector sizes not equal to
	* 2^9.
	*/
	PedConstraint*
	ped_device_get_constraint (PedDevice* dev)
	{
	int multiplier = dev->phys_sector_size / dev->sector_size;

	PedAlignment* start_align = ped_alignment_new (multiplier, multiplier);

	PedConstraint* c = ped_constraint_new (
	start_align, ped_alignment_any,
	ped_geometry_new (dev, 0, dev->length),
	ped_geometry_new (dev, 0, dev->length),
	1, dev->length);

	return c;
	}

	/** @} */