10.3 Registering

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int rsi_register(const struct rsi_hive *hives, uint32_t count, uint64_t max_sequence);

Opens /dev/pkm_registry and registers all count hives in one call, returning the source fd — the descriptor you then read(2) requests and write(2) responses on — or -1 with errno.

ArgumentMeaning
hives / countThe hives this source serves. count must be >= 1; the kernel enforces its configured MaxHivesPerSource limit.
max_sequenceThe highest sequence number this source has already persisted. The kernel resumes its global sequence counter past this value, so a source that has durable state from a previous run must report it here to avoid reusing sequence numbers. A fresh source with no persisted state passes 0.

Errors include EPERM (no SeTcbPrivilege), EINVAL, ENOSPC (over the hive limit), ENOMEM, EFAULT, and any error from the underlying /dev/pkm_registry open(2).

struct rsi_hive hive = {
    .name = "MyStore", .name_len = 7,
    .flags = 0,                                  /* global hive */
    .root_guid = { /* … 16 bytes … */ },
};

int src = rsi_register(&hive, 1, /*max_sequence=*/0);
if (src < 0) { perror("rsi_register"); return -1; }
/* `src` is now the source fd — serve the RSI protocol on it. */

The max_sequence parameter is the one piece of state a durable source must get right: on restart, scan your persisted data for the highest sequence you ever wrote and pass it, so the kernel never hands out a sequence number you've already used.

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