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Partition: libfdisk Reference Manual

Partition

Partition — generic label independent partition abstraction

Functions

int fdisk_add_partition ()
int fdisk_delete_all_partitions ()
int fdisk_delete_partition ()
int fdisk_get_partition ()
int fdisk_is_partition_used ()
int fdisk_set_partition ()
int fdisk_wipe_partition ()
struct fdisk_partition * fdisk_new_partition ()
int fdisk_partition_cmp_partno ()
int fdisk_partition_cmp_start ()
int fdisk_partition_end_follow_default ()
int fdisk_partition_end_is_default ()
const char * fdisk_partition_get_attrs ()
fdisk_sector_t fdisk_partition_get_end ()
const char * fdisk_partition_get_name ()
int fdisk_partition_get_parent ()
size_t fdisk_partition_get_partno ()
uint64_t fdisk_partition_get_size ()
uint64_t fdisk_partition_get_start ()
struct fdisk_parttype * fdisk_partition_get_type ()
const char * fdisk_partition_get_uuid ()
int fdisk_partition_has_end ()
int fdisk_partition_has_partno ()
int fdisk_partition_has_size ()
int fdisk_partition_has_start ()
int fdisk_partition_is_bootable ()
int fdisk_partition_is_container ()
int fdisk_partition_is_freespace ()
int fdisk_partition_is_nested ()
int fdisk_partition_is_used ()
int fdisk_partition_is_wholedisk ()
int fdisk_partition_next_partno ()
int fdisk_partition_partno_follow_default ()
int fdisk_partition_set_attrs ()
int fdisk_partition_set_name ()
int fdisk_partition_set_partno ()
int fdisk_partition_set_size ()
int fdisk_partition_set_start ()
int fdisk_partition_set_type ()
int fdisk_partition_set_uuid ()
int fdisk_partition_size_explicit ()
int fdisk_partition_start_follow_default ()
int fdisk_partition_start_is_default ()
int fdisk_partition_to_string ()
int fdisk_partition_unset_partno ()
int fdisk_partition_unset_size ()
int fdisk_partition_unset_start ()
void fdisk_ref_partition ()
void fdisk_reset_partition ()
void fdisk_unref_partition ()

Types and Values

Description

The fdisk_partition provides label independent abstraction. The partitions are not directly connected with partition table (label) data. Any change to fdisk_partition does not affects in-memory or on-disk label data.

The fdisk_partition is possible to use as a template for fdisk_add_partition() or fdisk_set_partition() operations.

Functions

fdisk_add_partition ()

int
fdisk_add_partition (struct fdisk_context *cxt,
                     struct fdisk_partition *pa,
                     size_t *partno);

If pa is not specified or any pa item is missing the libfdisk will ask by fdisk_ask_ API.

Adds a new partition to disklabel.

Parameters

cxt

fdisk context

 

pa

template for the partition (or NULL)

 

partno

NULL or returns new partition number

 

Returns

0 on success, <0 on error.


fdisk_delete_all_partitions ()

int
fdisk_delete_all_partitions (struct fdisk_context *cxt);

Delete all used partitions from disklabel.

Parameters

cxt

fdisk context

 

Returns

0 on success, otherwise, a corresponding error.


fdisk_delete_partition ()

int
fdisk_delete_partition (struct fdisk_context *cxt,
                        size_t partno);

Deletes a partno partition from disklabel.

Parameters

cxt

fdisk context

 

partno

partition number to delete (0 is the first partition)

 

Returns

0 on success, <0 on error


fdisk_get_partition ()

int
fdisk_get_partition (struct fdisk_context *cxt,
                     size_t partno,
                     struct fdisk_partition **pa);

Reads disklabel and fills in pa with data about partition n .

Note that partno may address unused partition and then this function does not fill anything to pa . See fdisk_is_partition_used(). If pa points to NULL then the function allocates a newly allocated fdisk_partition struct, use fdisk_unref_partition() to deallocate.

Parameters

cxt

context

 

partno

partition number (0 is the first partition)

 

pa

returns data about partition

 

Returns

0 on success, otherwise, a corresponding error.


fdisk_is_partition_used ()

int
fdisk_is_partition_used (struct fdisk_context *cxt,
                         size_t n);

This is faster than fdisk_get_partition() + fdisk_partition_is_used().

Parameters

cxt

context

 

n

partition number (0 is the first partition)

 

Returns

0 or 1


fdisk_set_partition ()

int
fdisk_set_partition (struct fdisk_context *cxt,
                     size_t partno,
                     struct fdisk_partition *pa);

Modifies disklabel according to setting with in pa .

Parameters

cxt

context

 

partno

partition number (0 is the first partition)

 

pa

new partition setting

 

Returns

0 on success, <0 on error.


fdisk_wipe_partition ()

int
fdisk_wipe_partition (struct fdisk_context *cxt,
                      size_t partno,
                      int enable);

Enable/disable filesystems/RAIDs wiping in area defined by partition start and size.

Parameters

cxt

fdisk context

 

partno

partition number

 

enable

0 or 1

 

Returns

<0 in case of error, 0 on success

Since: 2.29


fdisk_new_partition ()

struct fdisk_partition *
fdisk_new_partition (void);

Returns

new instance.


fdisk_partition_cmp_partno ()

int
fdisk_partition_cmp_partno (struct fdisk_partition *a,
                            struct fdisk_partition *b);

Compares partitions according to partition number See fdisk_table_sort_partitions().

Return: 0 if the same, <0 if b greater, >0 if a greater.

Parameters

a

partition

 

b

partition

 

fdisk_partition_cmp_start ()

int
fdisk_partition_cmp_start (struct fdisk_partition *a,
                           struct fdisk_partition *b);

Compares partitions according to start offset, See fdisk_table_sort_partitions().

Return: 0 if the same, <0 if b greater, >0 if a greater.

Parameters

a

partition

 

b

partition

 

fdisk_partition_end_follow_default ()

int
fdisk_partition_end_follow_default (struct fdisk_partition *pa,
                                    int enable);

When pa used as a template for fdisk_add_partition() when force label driver to use all the possible space for the new partition.

Parameters

pa

partition

 

enable

0|1

 

Returns

0 on success, <0 on error.


fdisk_partition_end_is_default ()

int
fdisk_partition_end_is_default (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition follows default


fdisk_partition_get_attrs ()

const char *
fdisk_partition_get_attrs (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

partition attributes in string format


fdisk_partition_get_end ()

fdisk_sector_t
fdisk_partition_get_end (struct fdisk_partition *pa);

This function may returns absolute non-sense, always check fdisk_partition_has_end().

Note that partition end is defined by fdisk_partition_set_start() and fdisk_partition_set_size().

Parameters

pa

partition

 

Returns

last partition sector LBA.


fdisk_partition_get_name ()

const char *
fdisk_partition_get_name (struct fdisk_partition *pa);

fdisk_partition_get_parent ()

int
fdisk_partition_get_parent (struct fdisk_partition *pa,
                            size_t *parent);

Parameters

pa

partition

 

parent

parent parno

 

Returns

returns devno of the parent


fdisk_partition_get_partno ()

size_t
fdisk_partition_get_partno (struct fdisk_partition *pa);

The zero is also valid partition number. The function may return random value when partno is undefined (for example after fdisk_partition_unset_partno()). Always use fdisk_partition_has_partno() to be sure that you work with valid numbers.

Parameters

pa

partition

 

Returns

partition number (0 is the first partition)


fdisk_partition_get_size ()

uint64_t
fdisk_partition_get_size (struct fdisk_partition *pa);

The zero is also valid size. The function may return random undefined value when size is undefined (for example after fdisk_partition_unset_size()). Always use fdisk_partition_has_size() to be sure that you work with valid numbers.

Parameters

pa

partition

 

Returns

size offset in sectors


fdisk_partition_get_start ()

uint64_t
fdisk_partition_get_start (struct fdisk_partition *pa);

The zero is also valid offset. The function may return random undefined value when start offset is undefined (for example after fdisk_partition_unset_start()). Always use fdisk_partition_has_start() to be sure that you work with valid numbers.

Parameters

pa

partition

 

Returns

start offset in sectors


fdisk_partition_get_type ()

struct fdisk_parttype *
fdisk_partition_get_type (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

pointer to partition type.


fdisk_partition_get_uuid ()

const char *
fdisk_partition_get_uuid (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

partition UUID as string


fdisk_partition_has_end ()

int
fdisk_partition_has_end (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition has defined last sector


fdisk_partition_has_partno ()

int
fdisk_partition_has_partno (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 or 0


fdisk_partition_has_size ()

int
fdisk_partition_has_size (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 or 0


fdisk_partition_has_start ()

int
fdisk_partition_has_start (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 or 0


fdisk_partition_is_bootable ()

int
fdisk_partition_is_bootable (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition has enabled boot flag


fdisk_partition_is_container ()

int
fdisk_partition_is_container (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition is container (e.g. MBR extended partition)


fdisk_partition_is_freespace ()

int
fdisk_partition_is_freespace (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if pa points to freespace


fdisk_partition_is_nested ()

int
fdisk_partition_is_nested (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition is nested (e.g. MBR logical partition)


fdisk_partition_is_used ()

int
fdisk_partition_is_used (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition points to some area


fdisk_partition_is_wholedisk ()

int
fdisk_partition_is_wholedisk (struct fdisk_partition *pa);

Parameters

pa

partition

 

Returns

1 if the partition is special whole-disk (e.g. SUN) partition


fdisk_partition_next_partno ()

int
fdisk_partition_next_partno (struct fdisk_partition *pa,
                             struct fdisk_context *cxt,
                             size_t *n);

If partno-follow-default (see fdisk_partition_partno_follow_default()) enabled then returns next expected partno, otherwise use Ask API to ask user for the next partno.

Parameters

pa

partition

 

cxt

context

 

n

returns partition number

 

Returns

0 on success, <0 on error


fdisk_partition_partno_follow_default ()

int
fdisk_partition_partno_follow_default (struct fdisk_partition *pa,
                                       int enable);

When pa used as a template for fdisk_add_partition() when force label driver to add a new partition to the default (next) position.

Parameters

pa

partition

 

enable

0|1

 

Returns

0 on success, <0 on error.


fdisk_partition_set_attrs ()

int
fdisk_partition_set_attrs (struct fdisk_partition *pa,
                           const char *attrs);

Sets attrs to pa .

Return: 0 on success, <0 on error.

Parameters

pa

partition

 

attrs

attributes

 

fdisk_partition_set_name ()

int
fdisk_partition_set_name (struct fdisk_partition *pa,
                          const char *name);

fdisk_partition_set_partno ()

int
fdisk_partition_set_partno (struct fdisk_partition *pa,
                            size_t num);

Note that zero is valid partno too. Use fdisk_partition_unset_partno() to undefine the partno.

Parameters

pa

partition

 

num

partition number (0 is the first partition, maximal is SIZE_MAX-1)

 

Returns

0 on success, <0 on error.


fdisk_partition_set_size ()

int
fdisk_partition_set_size (struct fdisk_partition *pa,
                          uint64_t sz);

Note that zero is valid size too. Use fdisk_partition_unset_size() to undefine the size.

Parameters

pa

partition

 

sz

size in sectors, maximal is UIN64_MAX-1

 

Returns

0 on success, <0 on error.


fdisk_partition_set_start ()

int
fdisk_partition_set_start (struct fdisk_partition *pa,
                           uint64_t off);

Note that zero is valid offset too. Use fdisk_partition_unset_start() to undefine the offset.

Parameters

pa

partition

 

off

offset in sectors, maximal is UINT64_MAX-1

 

Returns

0 on success, <0 on error.


fdisk_partition_set_type ()

int
fdisk_partition_set_type (struct fdisk_partition *pa,
                          struct fdisk_parttype *type);

Sets partition type.

Parameters

pa

partition

 

type

partition type

 

Returns

0 on success, <0 on error.


fdisk_partition_set_uuid ()

int
fdisk_partition_set_uuid (struct fdisk_partition *pa,
                          const char *uuid);

fdisk_partition_size_explicit ()

int
fdisk_partition_size_explicit (struct fdisk_partition *pa,
                               int enable);

By default libfdisk aligns the size when add the new partition (by fdisk_add_partition()). If you want to disable this functionality use enable = 1.

Parameters

pa

partition

 

enable

0|1

 

Returns

0 on success, <0 on error.


fdisk_partition_start_follow_default ()

int
fdisk_partition_start_follow_default (struct fdisk_partition *pa,
                                      int enable);

When pa used as a template for fdisk_add_partition() when force label driver to use the first possible space for the new partition.

Parameters

pa

partition

 

enable

0|1

 

Returns

0 on success, <0 on error.


fdisk_partition_start_is_default ()

int
fdisk_partition_start_is_default (struct fdisk_partition *pa);

See fdisk_partition_start_follow_default().

Parameters

pa

partition

 

Returns

1 if the partition follows default


fdisk_partition_to_string ()

int
fdisk_partition_to_string (struct fdisk_partition *pa,
                           struct fdisk_context *cxt,
                           int id,
                           char **data);

Returns info about partition converted to printable string.

For example

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struct fdisk_partition *pa;

fdisk_get_partition(cxt, 0, &pa);
fdisk_partition_to_string(pa, FDISK_FIELD_UUID, &data);
printf("first partition uuid: %s\n", data);
free(data);
fdisk_unref_partition(pa);

returns UUID for the first partition.

Parameters

pa

partition

 

cxt

context

 

id

field (FDISK_FIELD_*)

 

data

returns string with allocated data

 

Returns

0 on success, otherwise, a corresponding error.


fdisk_partition_unset_partno ()

int
fdisk_partition_unset_partno (struct fdisk_partition *pa);

Sets the partno as undefined. See fdisk_partition_has_partno().

Parameters

pa

partition

 

Returns

0 on success, <0 on error.


fdisk_partition_unset_size ()

int
fdisk_partition_unset_size (struct fdisk_partition *pa);

Sets the size as undefined. See fdisk_partition_has_size().

Parameters

pa

partition

 

Returns

0 on success, <0 on error.


fdisk_partition_unset_start ()

int
fdisk_partition_unset_start (struct fdisk_partition *pa);

Sets the size as undefined. See fdisk_partition_has_start().

Parameters

pa

partition

 

Returns

0 on success, <0 on error.


fdisk_ref_partition ()

void
fdisk_ref_partition (struct fdisk_partition *pa);

Increments reference counter.

Parameters

pa

partition pointer

 

fdisk_reset_partition ()

void
fdisk_reset_partition (struct fdisk_partition *pa);

Resets partition content.

Parameters

pa

partition

 

fdisk_unref_partition ()

void
fdisk_unref_partition (struct fdisk_partition *pa);

Decrements reference counter, on zero the pa is automatically deallocated.

Parameters

pa

partition pointer

 

Types and Values

struct fdisk_partition

struct fdisk_partition;

Partition abstraction (and template).