ra8_fs_fat_gpt_internal.h File Reference

Cross-TU prototypes for the GPT partition locators. More...

#include "ra8_attributes.h"
#include "ra8_fs_fat_types_internal.h"

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Functions
ra8_err_t	priv_gpt_locate_volume (const ra8_fs_mount_t *m, uint64_t *out_base)
	Locate the first mountable partition on a GPT disk (auto-select).
ra8_err_t	priv_gpt_locate_partition (const ra8_fs_mount_t *m, uint8_t index, uint64_t *out_base)
	Locate a GPT partition chosen by entry-array index.

Detailed Description

Cross-TU prototypes for the GPT partition locators.

The two entry points ra8_fs_fat_gpt.c offers the mount path: locate the first mountable partition on a GPT disk, and locate one by entry index. Split out as a themed sub-header (like the exFAT stream and directory seams) rather than grown onto the alphabetical prototype headers, which sit against the source-size cap.

Copyright

Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since

0.1.0

Definition in file ra8_fs_fat_gpt_internal.h.

Function Documentation

priv_gpt_locate_partition()

ra8_err_t priv_gpt_locate_partition	(	const ra8_fs_mount_t *	m,
		uint8_t	index,
		uint64_t *	out_base )

Locate a GPT partition chosen by entry-array index.

Reads the header geometry via ::priv_gpt_read_geom, bounds-checks index against the (clamped) entry count, reads the sector holding that entry, and validates it via ::priv_gpt_entry_select.

Parameters

[in,out]	m	Mount whose backend supplies the sectors.
[in]	index	Zero-based GPT entry-array index.
[out]	out_base	Receives the selected partition's first LBA.

Returns

Error code.

Return values

k_ra8_ok	out_base holds the volume base.
k_ra8_err_out_of_range	index is past the entry count.
k_ra8_err_not_found	The selected entry is empty.
k_ra8_err_not_supported	Entry-array geometry, or an entry LBA, this backend cannot address.
k_ra8_err_validation_failed	No header, or a malformed entry.
k_ra8_err_*	Backend read failure.

Precondition

m->partition_base_lba is still 0 (reads are absolute).

out_base is non-NULL.

Postcondition

On k_ra8_ok out_base holds a non-zero LBA.

g_fs_scratch is overwritten (callers must re-read their sector).

Note

Not thread-safe – uses module-level scratch.

Since

0.1.0

Definition at line 317 of file ra8_fs_fat_gpt.c.

References g_fs_scratch, internal_gpt_entry_select(), internal_gpt_read_geom(), k_gpt_entry_bytes, k_ra8_err_out_of_range, k_ra8_ok, priv_bps(), and priv_read_sector().

Referenced by internal_locate_indexed().

priv_gpt_locate_volume()

ra8_err_t priv_gpt_locate_volume	(	const ra8_fs_mount_t *	m,
		uint64_t *	out_base )

Locate the first mountable partition on a GPT disk (auto-select).

Reads the header geometry via ::priv_gpt_read_geom, then scans the entries via ::priv_gpt_scan_entries (Microsoft Basic Data preferred, else the first allocated entry of any type).

Parameters

[in,out]	m	Mount whose backend supplies the sectors.
[out]	out_base	Receives the chosen partition's first LBA.

Returns

Error code.

Return values

k_ra8_ok	out_base holds the volume base.
k_ra8_err_validation_failed	No "EFI PART" header at LBA 1.
k_ra8_err_not_supported	Non-standard entry size or array LBA.
k_ra8_err_*	Backend read failure or no entry found.

Precondition

m->partition_base_lba is still 0 (reads are absolute).

out_base is non-NULL.

Postcondition

On k_ra8_ok out_base holds a non-zero LBA.

g_fs_scratch is overwritten (callers must re-read their sector).

Note

Not thread-safe – uses module-level scratch.

Since

0.1.0

Definition at line 263 of file ra8_fs_fat_gpt.c.

References internal_gpt_read_geom(), internal_gpt_scan_entries(), and k_ra8_ok.

Referenced by internal_read_boot_sector().