libmdbx/mdbx.c

/*
 * Copyright (c) 2015,2016 Leonid Yuriev <leo@yuriev.ru>.
 * Copyright (c) 2015,2016 Peter-Service R&D LLC.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */

#include "mdbx.h"

int mdb_runtime_flags = MDBX_DBG_PRINT
#if MDB_DEBUG
		| MDBX_DBG_ASSERT
#endif
#if MDB_DEBUG > 1
		| MDBX_DBG_TRACE
#endif
#if MDB_DEBUG > 2
		| MDBX_DBG_AUDIT
#endif
#if MDB_DEBUG > 3
		| MDBX_DBG_EXTRA
#endif
	;

static MDBX_debug_func *mdb_debug_logger;

int mdbx_setup_debug(int flags, MDBX_debug_func* logger, long edge_txn);

#include "mdb.c"

int __cold
mdbx_setup_debug(int flags, MDBX_debug_func* logger, long edge_txn) {
	unsigned ret = mdb_runtime_flags;
	if (flags != (int) MDBX_DBG_DNT)
		mdb_runtime_flags = flags;
	if (logger != (MDBX_debug_func*) MDBX_DBG_DNT)
		mdb_debug_logger = logger;
	if (edge_txn != (long) MDBX_DBG_DNT) {
#if MDB_DEBUG
		mdb_debug_edge = edge_txn;
#endif
	}
	return ret;
}

static txnid_t __cold
mdbx_oomkick(MDB_env *env, txnid_t oldest)
{
	int retry;
	txnid_t snap;
	mdb_debug("DB size maxed out");

	for(retry = 0; ; ++retry) {
		int reader;

		if (mdb_reader_check(env, NULL))
			break;

		snap = mdb_find_oldest(env, &reader);
		if (oldest < snap || reader < 0) {
			if (retry && env->me_oom_func) {
				/* LY: notify end of oom-loop */
				env->me_oom_func(env, 0, 0, oldest, snap - oldest, -retry);
			}
			return snap;
		}

		MDB_reader *r;
		pthread_t tid;
		pid_t pid;
		int rc;

		if (!env->me_oom_func)
			break;

		r = &env->me_txns->mti_readers[ reader ];
		pid = r->mr_pid;
		tid = r->mr_tid;
		if (r->mr_txnid != oldest || pid <= 0)
			continue;

		rc = env->me_oom_func(env, pid, (void*) tid, oldest,
			mdb_meta_head_w(env)->mm_txnid - oldest, retry);
		if (rc < 0)
			break;

		if (rc) {
			r->mr_txnid = ~(txnid_t)0;
			if (rc > 1) {
				r->mr_tid = 0;
				r->mr_pid = 0;
				mdbx_coherent_barrier();
			}
		}
	}

	if (retry && env->me_oom_func) {
		/* LY: notify end of oom-loop */
		env->me_oom_func(env, 0, 0, oldest, 0, -retry);
	}
	return mdb_find_oldest(env, NULL);
}

int __cold
mdbx_env_set_syncbytes(MDB_env *env, size_t bytes)
{
	if (unlikely(!env))
		return EINVAL;

	if(unlikely(env->me_signature != MDBX_ME_SIGNATURE))
		return MDB_VERSION_MISMATCH;

	env->me_sync_threshold = bytes;
	return env->me_map ? mdb_env_sync(env, 0) : 0;
}

void __cold
mdbx_env_set_oomfunc(MDB_env *env, MDBX_oom_func *oomfunc)
{
	if (likely(env && env->me_signature == MDBX_ME_SIGNATURE))
		env->me_oom_func = oomfunc;
}

MDBX_oom_func* __cold
mdbx_env_get_oomfunc(MDB_env *env)
{
	return likely(env && env->me_signature == MDBX_ME_SIGNATURE)
		? env->me_oom_func : NULL;
}

ATTRIBUTE_NO_SANITIZE_THREAD /* LY: avoid tsan-trap by me_txn, mm_last_pg and mt_next_pgno */
int mdbx_txn_straggler(MDB_txn *txn, int *percent)
{
	MDB_env	*env;
	MDB_meta *meta;
	txnid_t lag;

	if(unlikely(!txn))
		return -EINVAL;

	if(unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
		return MDB_VERSION_MISMATCH;

	if (unlikely(! txn->mt_u.reader))
		return -1;

	env = txn->mt_env;
	meta = mdb_meta_head_r(env);
	if (percent) {
		size_t maxpg = env->me_maxpg;
		size_t last = meta->mm_last_pg + 1;
		if (env->me_txn)
			last = env->me_txn0->mt_next_pgno;
		*percent = (last * 100ull + maxpg / 2) / maxpg;
	}
	lag = meta->mm_txnid - txn->mt_u.reader->mr_txnid;
	return (0 > (long) lag) ? ~0u >> 1: lag;
}

typedef struct mdb_walk_ctx {
	MDB_txn *mw_txn;
	void *mw_user;
	MDBX_pgvisitor_func *mw_visitor;
} mdb_walk_ctx_t;

/** Depth-first tree traversal. */
static int __cold
mdb_env_walk(mdb_walk_ctx_t *ctx, const char* dbi, pgno_t pg, int flags, int deep)
{
	MDB_page *mp;
	int rc, i, nkeys;
	unsigned header_size, unused_size, payload_size, align_bytes;
	const char* type;

	if (pg == P_INVALID)
		return MDB_SUCCESS; /* empty db */

	rc = mdb_page_get(ctx->mw_txn, pg, &mp, NULL);
	if (rc)
		return rc;
	if (pg != mp->mp_p.p_pgno)
		return MDB_CORRUPTED;

	nkeys = NUMKEYS(mp);
	header_size = IS_LEAF2(mp) ? PAGEHDRSZ : PAGEBASE + mp->mp_lower;
	unused_size = SIZELEFT(mp);
	payload_size = 0;

	/* LY: Don't use mask here, e.g bitwise (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP).
	 * Pages should not me marked dirty/loose or otherwise. */
	switch (mp->mp_flags) {
	case P_BRANCH:
		type = "branch";
		if (nkeys < 1)
			return MDB_CORRUPTED;
		break;
	case P_LEAF:
		type = "leaf";
		break;
	case P_LEAF|P_SUBP:
		type = "dupsort-subleaf";
		break;
	case P_LEAF|P_LEAF2:
		type = "dupfixed-leaf";
		break;
	case P_LEAF|P_LEAF2|P_SUBP:
		type = "dupsort-dupfixed-subleaf";
		break;
	case P_META:
	case P_OVERFLOW:
	default:
		return MDB_CORRUPTED;
	}

	for (align_bytes = i = 0; i < nkeys;
		 align_bytes += ((payload_size + align_bytes) & 1), i++) {
		MDB_node *node;

		if (IS_LEAF2(mp)) {
			/* LEAF2 pages have no mp_ptrs[] or node headers */
			payload_size += mp->mp_leaf2_ksize;
			continue;
		}

		node = NODEPTR(mp, i);
		payload_size += NODESIZE + node->mn_ksize;

		if (IS_BRANCH(mp)) {
			rc = mdb_env_walk(ctx, dbi, NODEPGNO(node), flags, deep);
			if (rc)
				return rc;
			continue;
		}

		assert(IS_LEAF(mp));
		if (node->mn_ksize < 1)
			return MDB_CORRUPTED;
		if (node->mn_flags & F_BIGDATA) {
			MDB_page *omp;
			pgno_t *opg;
			size_t over_header, over_payload, over_unused;

			payload_size += sizeof(pgno_t);
			opg = NODEDATA(node);
			rc = mdb_page_get(ctx->mw_txn, *opg, &omp, NULL);
			if (rc)
				return rc;
			if (*opg != omp->mp_p.p_pgno)
				return MDB_CORRUPTED;
			/* LY: Don't use mask here, e.g bitwise (P_BRANCH|P_LEAF|P_LEAF2|P_META|P_OVERFLOW|P_SUBP).
			 * Pages should not me marked dirty/loose or otherwise. */
			if (P_OVERFLOW != omp->mp_flags)
				return MDB_CORRUPTED;

			over_header = PAGEHDRSZ;
			over_payload = NODEDSZ(node);
			over_unused = omp->mp_pages * ctx->mw_txn->mt_env->me_psize
					- over_payload - over_header;

			rc = ctx->mw_visitor(*opg, omp->mp_pages, ctx->mw_user, dbi,
					"overflow-data", 1, over_payload, over_header, over_unused);
			if (rc)
				return rc;
			continue;
		}

		payload_size += NODEDSZ(node);
		if (node->mn_flags & F_SUBDATA) {
			MDB_db *db = NODEDATA(node);
			char* name = NULL;

			if (NODEDSZ(node) < 1)
				return MDB_CORRUPTED;
			if (! (node->mn_flags & F_DUPDATA)) {
				name = NODEKEY(node);
				int namelen = (char*) db - name;
				name = memcpy(alloca(namelen + 1), name, namelen);
				name[namelen] = 0;
			}
			rc = mdb_env_walk(ctx, (name && name[0]) ? name : dbi,
					db->md_root, node->mn_flags & F_DUPDATA, deep + 1);
			if (rc)
				return rc;
		}
	}

	return ctx->mw_visitor(mp->mp_p.p_pgno, 1, ctx->mw_user, dbi, type,
		nkeys, payload_size, header_size, unused_size + align_bytes);
}

int __cold
mdbx_env_pgwalk(MDB_txn *txn, MDBX_pgvisitor_func* visitor, void* user)
{
	mdb_walk_ctx_t ctx;
	int rc;

	if (unlikely(!txn))
		return MDB_BAD_TXN;
	if (unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
		return MDB_VERSION_MISMATCH;

	ctx.mw_txn = txn;
	ctx.mw_user = user;
	ctx.mw_visitor = visitor;

	rc = visitor(0, 2, user, "lmdb", "meta", 2, sizeof(MDB_meta)*2, PAGEHDRSZ*2,
				 (txn->mt_env->me_psize - sizeof(MDB_meta) - PAGEHDRSZ) *2);
	if (! rc)
		rc = mdb_env_walk(&ctx, "free", txn->mt_dbs[FREE_DBI].md_root, 0, 0);
	if (! rc)
		rc = mdb_env_walk(&ctx, "main", txn->mt_dbs[MAIN_DBI].md_root, 0, 0);
	if (! rc)
		rc = visitor(P_INVALID, 0, user, NULL, NULL, 0, 0, 0, 0);
	return rc;
}

int mdbx_canary_put(MDB_txn *txn, const mdbx_canary* canary)
{
	if (unlikely(!txn))
		return EINVAL;

	if (unlikely(txn->mt_signature != MDBX_MT_SIGNATURE))
		return MDB_VERSION_MISMATCH;

	if (unlikely(F_ISSET(txn->mt_flags, MDB_TXN_RDONLY)))
		return EACCES;

	if (likely(canary)) {
		txn->mt_canary.x = canary->x;
		txn->mt_canary.y = canary->y;
		txn->mt_canary.z = canary->z;
	}
	txn->mt_canary.v = txn->mt_txnid;

	return MDB_SUCCESS;
}

size_t mdbx_canary_get(MDB_txn *txn, mdbx_canary* canary)
{
	if(unlikely(!txn || txn->mt_signature != MDBX_MT_SIGNATURE))
		return 0;

	if (likely(canary))
		*canary = txn->mt_canary;

	return txn->mt_txnid;
}