diff options
Diffstat (limited to 'bundled/tdb/common/check.c')
-rw-r--r-- | bundled/tdb/common/check.c | 423 |
1 files changed, 0 insertions, 423 deletions
diff --git a/bundled/tdb/common/check.c b/bundled/tdb/common/check.c deleted file mode 100644 index 2c640434..00000000 --- a/bundled/tdb/common/check.c +++ /dev/null @@ -1,423 +0,0 @@ - /* - Unix SMB/CIFS implementation. - - trivial database library - - Copyright (C) Rusty Russell 2009 - - ** NOTE! The following LGPL license applies to the tdb - ** library. This does NOT imply that all of Samba is released - ** under the LGPL - - This library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 3 of the License, or (at your option) any later version. - - This library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with this library; if not, see <http://www.gnu.org/licenses/>. -*/ -#include "tdb_private.h" - -/* Since we opened it, these shouldn't fail unless it's recent corruption. */ -static bool tdb_check_header(struct tdb_context *tdb, tdb_off_t *recovery) -{ - struct tdb_header hdr; - - if (tdb->methods->tdb_read(tdb, 0, &hdr, sizeof(hdr), DOCONV()) == -1) - return false; - if (strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) - goto corrupt; - - CONVERT(hdr); - if (hdr.version != TDB_VERSION) - goto corrupt; - - if (hdr.rwlocks != 0) - goto corrupt; - - if (hdr.hash_size == 0) - goto corrupt; - - if (hdr.hash_size != tdb->header.hash_size) - goto corrupt; - - if (hdr.recovery_start != 0 && - hdr.recovery_start < TDB_DATA_START(tdb->header.hash_size)) - goto corrupt; - - *recovery = hdr.recovery_start; - return true; - -corrupt: - tdb->ecode = TDB_ERR_CORRUPT; - TDB_LOG((tdb, TDB_DEBUG_ERROR, "Header is corrupt\n")); - return false; -} - -/* Generic record header check. */ -static bool tdb_check_record(struct tdb_context *tdb, - tdb_off_t off, - const struct tdb_record *rec) -{ - tdb_off_t tailer; - - /* Check rec->next: 0 or points to record offset, aligned. */ - if (rec->next > 0 && rec->next < TDB_DATA_START(tdb->header.hash_size)){ - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d too small next %d\n", - off, rec->next)); - goto corrupt; - } - if (rec->next + sizeof(*rec) < rec->next) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d too large next %d\n", - off, rec->next)); - goto corrupt; - } - if ((rec->next % TDB_ALIGNMENT) != 0) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d misaligned next %d\n", - off, rec->next)); - goto corrupt; - } - if (tdb->methods->tdb_oob(tdb, rec->next+sizeof(*rec), 0)) - goto corrupt; - - /* Check rec_len: similar to rec->next, implies next record. */ - if ((rec->rec_len % TDB_ALIGNMENT) != 0) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d misaligned length %d\n", - off, rec->rec_len)); - goto corrupt; - } - /* Must fit tailer. */ - if (rec->rec_len < sizeof(tailer)) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d too short length %d\n", - off, rec->rec_len)); - goto corrupt; - } - /* OOB allows "right at the end" access, so this works for last rec. */ - if (tdb->methods->tdb_oob(tdb, off+sizeof(*rec)+rec->rec_len, 0)) - goto corrupt; - - /* Check tailer. */ - if (tdb_ofs_read(tdb, off+sizeof(*rec)+rec->rec_len-sizeof(tailer), - &tailer) == -1) - goto corrupt; - if (tailer != sizeof(*rec) + rec->rec_len) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d invalid tailer\n", off)); - goto corrupt; - } - - return true; - -corrupt: - tdb->ecode = TDB_ERR_CORRUPT; - return false; -} - -/* Grab some bytes: may copy if can't use mmap. - Caller has already done bounds check. */ -static TDB_DATA get_bytes(struct tdb_context *tdb, - tdb_off_t off, tdb_len_t len) -{ - TDB_DATA d; - - d.dsize = len; - - if (tdb->transaction == NULL && tdb->map_ptr != NULL) - d.dptr = (unsigned char *)tdb->map_ptr + off; - else - d.dptr = tdb_alloc_read(tdb, off, d.dsize); - return d; -} - -/* Frees data if we're not able to simply use mmap. */ -static void put_bytes(struct tdb_context *tdb, TDB_DATA d) -{ - if (tdb->transaction == NULL && tdb->map_ptr != NULL) - return; - free(d.dptr); -} - -/* We use the excellent Jenkins lookup3 hash; this is based on hash_word2. - * See: http://burtleburtle.net/bob/c/lookup3.c - */ -#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) -static void hash(uint32_t key, uint32_t *pc, uint32_t *pb) -{ - uint32_t a,b,c; - - /* Set up the internal state */ - a = b = c = 0xdeadbeef + *pc; - c += *pb; - a += key; - c ^= b; c -= rot(b,14); - a ^= c; a -= rot(c,11); - b ^= a; b -= rot(a,25); - c ^= b; c -= rot(b,16); - a ^= c; a -= rot(c,4); - b ^= a; b -= rot(a,14); - c ^= b; c -= rot(b,24); - *pc=c; *pb=b; -} - -/* - We want to check that all free records are in the free list - (only once), and all free list entries are free records. Similarly - for each hash chain of used records. - - Doing that naively (without walking hash chains, since we want to be - linear) means keeping a list of records which have been seen in each - hash chain, and another of records pointed to (ie. next pointers - from records and the initial hash chain heads). These two lists - should be equal. This will take 8 bytes per record, and require - sorting at the end. - - So instead, we record each offset in a bitmap such a way that - recording it twice will cancel out. Since each offset should appear - exactly twice, the bitmap should be zero at the end. - - The approach was inspired by Bloom Filters (see Wikipedia). For - each value, we flip K bits in a bitmap of size N. The number of - distinct arrangements is: - - N! / (K! * (N-K)!) - - Of course, not all arrangements are actually distinct, but testing - shows this formula to be close enough. - - So, if K == 8 and N == 256, the probability of two things flipping the same - bits is 1 in 409,663,695,276,000. - - Given that ldb uses a hash size of 10000, using 32 bytes per hash chain - (320k) seems reasonable. -*/ -#define NUM_HASHES 8 -#define BITMAP_BITS 256 - -static void bit_flip(unsigned char bits[], unsigned int idx) -{ - bits[idx / CHAR_BIT] ^= (1 << (idx % CHAR_BIT)); -} - -/* We record offsets in a bitmap for the particular chain it should be in. */ -static void record_offset(unsigned char bits[], tdb_off_t off) -{ - uint32_t h1 = off, h2 = 0; - unsigned int i; - - /* We get two good hash values out of jhash2, so we use both. Then - * we keep going to produce further hash values. */ - for (i = 0; i < NUM_HASHES / 2; i++) { - hash(off, &h1, &h2); - bit_flip(bits, h1 % BITMAP_BITS); - bit_flip(bits, h2 % BITMAP_BITS); - h2++; - } -} - -/* Check that an in-use record is valid. */ -static bool tdb_check_used_record(struct tdb_context *tdb, - tdb_off_t off, - const struct tdb_record *rec, - unsigned char **hashes, - int (*check)(TDB_DATA, TDB_DATA, void *), - void *private_data) -{ - TDB_DATA key, data; - - if (!tdb_check_record(tdb, off, rec)) - return false; - - /* key + data + tailer must fit in record */ - if (rec->key_len + rec->data_len + sizeof(tdb_off_t) > rec->rec_len) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d too short for contents\n", off)); - return false; - } - - key = get_bytes(tdb, off + sizeof(*rec), rec->key_len); - if (!key.dptr) - return false; - - if (tdb->hash_fn(&key) != rec->full_hash) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Record offset %d has incorrect hash\n", off)); - goto fail_put_key; - } - - /* Mark this offset as a known value for this hash bucket. */ - record_offset(hashes[BUCKET(rec->full_hash)+1], off); - /* And similarly if the next pointer is valid. */ - if (rec->next) - record_offset(hashes[BUCKET(rec->full_hash)+1], rec->next); - - /* If they supply a check function and this record isn't dead, - get data and feed it. */ - if (check && rec->magic != TDB_DEAD_MAGIC) { - data = get_bytes(tdb, off + sizeof(*rec) + rec->key_len, - rec->data_len); - if (!data.dptr) - goto fail_put_key; - - if (check(key, data, private_data) == -1) - goto fail_put_data; - put_bytes(tdb, data); - } - - put_bytes(tdb, key); - return true; - -fail_put_data: - put_bytes(tdb, data); -fail_put_key: - put_bytes(tdb, key); - return false; -} - -/* Check that an unused record is valid. */ -static bool tdb_check_free_record(struct tdb_context *tdb, - tdb_off_t off, - const struct tdb_record *rec, - unsigned char **hashes) -{ - if (!tdb_check_record(tdb, off, rec)) - return false; - - /* Mark this offset as a known value for the free list. */ - record_offset(hashes[0], off); - /* And similarly if the next pointer is valid. */ - if (rec->next) - record_offset(hashes[0], rec->next); - return true; -} - -int tdb_check(struct tdb_context *tdb, - int (*check)(TDB_DATA key, TDB_DATA data, void *private_data), - void *private_data) -{ - unsigned int h; - unsigned char **hashes; - tdb_off_t off, recovery_start; - struct tdb_record rec; - bool found_recovery = false; - - if (tdb_lockall_read(tdb) == -1) - return -1; - - /* Make sure we know true size of the underlying file. */ - tdb->methods->tdb_oob(tdb, tdb->map_size + 1, 1); - - /* Header must be OK: also gets us the recovery ptr, if any. */ - if (!tdb_check_header(tdb, &recovery_start)) - goto unlock; - - /* We should have the whole header, too. */ - if (tdb->map_size < TDB_DATA_START(tdb->header.hash_size)) { - tdb->ecode = TDB_ERR_CORRUPT; - TDB_LOG((tdb, TDB_DEBUG_ERROR, "File too short for hashes\n")); - goto unlock; - } - - /* One big malloc: pointers then bit arrays. */ - hashes = (unsigned char **)calloc( - 1, sizeof(hashes[0]) * (1+tdb->header.hash_size) - + BITMAP_BITS / CHAR_BIT * (1+tdb->header.hash_size)); - if (!hashes) { - tdb->ecode = TDB_ERR_OOM; - goto unlock; - } - - /* Initialize pointers */ - hashes[0] = (unsigned char *)(&hashes[1+tdb->header.hash_size]); - for (h = 1; h < 1+tdb->header.hash_size; h++) - hashes[h] = hashes[h-1] + BITMAP_BITS / CHAR_BIT; - - /* Freelist and hash headers are all in a row: read them. */ - for (h = 0; h < 1+tdb->header.hash_size; h++) { - if (tdb_ofs_read(tdb, FREELIST_TOP + h*sizeof(tdb_off_t), - &off) == -1) - goto free; - if (off) - record_offset(hashes[h], off); - } - - /* For each record, read it in and check it's ok. */ - for (off = TDB_DATA_START(tdb->header.hash_size); - off < tdb->map_size; - off += sizeof(rec) + rec.rec_len) { - if (tdb->methods->tdb_read(tdb, off, &rec, sizeof(rec), - DOCONV()) == -1) - goto free; - switch (rec.magic) { - case TDB_MAGIC: - case TDB_DEAD_MAGIC: - if (!tdb_check_used_record(tdb, off, &rec, hashes, - check, private_data)) - goto free; - break; - case TDB_FREE_MAGIC: - if (!tdb_check_free_record(tdb, off, &rec, hashes)) - goto free; - break; - case TDB_RECOVERY_MAGIC: - case TDB_RECOVERY_INVALID_MAGIC: - if (recovery_start != off) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Unexpected recovery record at offset %d\n", - off)); - goto free; - } - found_recovery = true; - break; - default: - tdb->ecode = TDB_ERR_CORRUPT; - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Bad magic 0x%x at offset %d\n", - rec.magic, off)); - goto free; - } - } - - /* Now, hashes should all be empty: each record exists and is referred - * to by one other. */ - for (h = 0; h < 1+tdb->header.hash_size; h++) { - unsigned int i; - for (i = 0; i < BITMAP_BITS / CHAR_BIT; i++) { - if (hashes[h][i] != 0) { - tdb->ecode = TDB_ERR_CORRUPT; - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Hashes do not match records\n")); - goto free; - } - } - } - - /* We must have found recovery area if there was one. */ - if (recovery_start != 0 && !found_recovery) { - TDB_LOG((tdb, TDB_DEBUG_ERROR, - "Expected %s recovery area, got %s\n", - recovery_start ? "a" : "no", - found_recovery ? "one" : "none")); - goto free; - } - - free(hashes); - tdb_unlockall_read(tdb); - return 0; - -free: - free(hashes); -unlock: - tdb_unlockall_read(tdb); - return -1; -} |