man pages section 3: Extended Library Functions

efi_alloc_and_read(3EXT)

Name

efi_alloc_and_init, efi_alloc_and_read, efi_free, efi_write– manipulate a disk's EFI Partition Table

Synopsis

cc [ flag … ] file… -lefi [ library … ]
#include <sys/vtoc.h>
#include <sys/efi_partition.h>

int efi_alloc_and_init(int fd, uint32_t nparts, dk_gpt_t **vtoc);

int efi_alloc_and_read(int fd, dk_gpt_t **vtoc);

void efi_free(dk_gpt_t *vtoc);

int efi_write(int fd, dk_gpt_t *vtoc);

Description

The efi_alloc_and_init() function initializes the dk_gpt_t structure specified by vtoc in preparation for a call to efi_write(). It calculates and initializes the efi_version, efi_lbasize, efi_nparts, efi_first_u_lba, efi_last_lba, and efi_last_u_lba members of this sturcture. The caller can then set the efi_nparts member.

The efi_alloc_and_read() function allocates memory and returns the partition table.

The efi_free() function frees the memory allocated by efi_alloc_and_init() and efi_alloc_and_read().

The efi_write() function writes the EFI partition table.

The fd argument refers to any slice on a raw disk, opened with O_NDELAY. See open(2).

The nparts argument specifies the number of desired partitions.

The vtoc argument is a dk_gpt_t structure that describes an EFI partition table and contains at least the following members:

uint_t          efi_version;     /* set to EFI_VERSION_CURRENT */
uint_t          efi_nparts;      /* number of partitions in efi_parts */
uint_t          efi_lbasize;     /* size of block in bytes */
diskaddr_t      efi_last_lba;    /* last block on the disk */
diskaddr_t      efi_first_u_lba; /* first block after labels */
diskaddr_t      efi_last_u_lba;  /* last block before backup labels */
struct dk_part  efi_parts[];     /* array of partitions */

Return Values

Upon successful completion, efi_alloc_and_init() returns 0. Otherwise it returns VT_EIO if an I/O operation to the disk fails.

Upon successful completion, efi_alloc_and_read() returns a positive integer indicating the slice index associated with the open file descriptor. Otherwise, it returns a negative integer to indicate one of the following:

VT_EIO: An I/O error occurred.
VT_ERROR: An unknown error occurred.
VT_EINVAL: An EFI label was not found.

Upon successful completion, efi_write() returns 0. Otherwise, it returns a negative integer to indicate one of the following:

VT_EIO: An I/O error occurred.
VT_ERROR: An unknown error occurred.
VT_EINVAL: The label contains incorrect data.

Usage

The EFI label is used on disks with more than 1³²-1 blocks. For compatibility reasons, the read_vtoc(3EXT) and write_vtoc() functions should be used on smaller disks. The application should attempt the read_vtoc() or write_vtoc() call, check for an error of VT_ENOTSUP, then call the analogous EFI function.

Attributes

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving
MT-Level	Unsafe