/*
 * zuse_cert_devblock.h -- on-disk record format for Zuse's cert, stored
 * in devblock_from_top=0 of the top-of-device system-metadata fence
 * (block_subsystem.h's blk_meta_zone_read()/write(), Phase 8, FABRIC-3.md
 * §C). Raw, unpacked 4 KiB devblock -- same convention as the volume
 * header itself (magic + version + fields + pad-to-4096, real CRC from
 * day one, matching homeblocks_sig_t's own precedent for exactly this
 * reason: this gates a real security check, not a placeholder).
 *
 * Deliberately its own header, not inlined at the one call site that
 * uses it today (kernel_main.c's first-boot mint-or-load): the ongoing
 * `MINT` word (still open, FABRIC-3.md) will be a second consumer of
 * this exact format later, and the format should be stable and
 * documented once rather than ad-hoc.
 */
#ifndef STARKERNEL_ZUSE_CERT_DEVBLOCK_H
#define STARKERNEL_ZUSE_CERT_DEVBLOCK_H

#include <stdint.h>

/* Packed via shifts, not a hand-computed hex literal -- this project's
 * own standing lesson about hand-derived numeric constants in this
 * class of code (see FABRIC-3.md's Ed25519/scalar25519 writeups). */
#define ZUSE_CERT_DEVBLOCK_MAGIC \
    ((uint32_t)'Z' | ((uint32_t)'U' << 8) | ((uint32_t)'S' << 16) | ((uint32_t)'E' << 24))

#define ZUSE_CERT_DEVBLOCK_VERSION 1u

typedef struct {
    uint32_t magic;      /* ZUSE_CERT_DEVBLOCK_MAGIC; anything else means
                           * "not a real cert yet" (blank/foreign bytes),
                           * not a format-corruption error */
    uint32_t version;    /* ZUSE_CERT_DEVBLOCK_VERSION */
    uint8_t  seed[32];   /* Ed25519 seed -- the private identity */
    uint8_t  pubkey[32]; /* Ed25519 public key derived from seed at mint time */
    uint64_t crc;        /* CRC-64/ISO (block_subsystem.h's compute_crc64())
                           * over every byte of this struct up to (not
                           * including) this field -- real from day one,
                           * this gates a real security check */
    uint8_t  _pad[4096 - (4 + 4 + 32 + 32 + 8)];
} zuse_cert_devblock_t;

_Static_assert(sizeof(zuse_cert_devblock_t) == 4096,
               "zuse_cert_devblock_t must be exactly one 4 KiB devblock");

#endif /* STARKERNEL_ZUSE_CERT_DEVBLOCK_H */