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Diffstat (limited to 'source/tdb/tdb.c')
| -rw-r--r-- | source/tdb/tdb.c | 1742 |
1 files changed, 1742 insertions, 0 deletions
diff --git a/source/tdb/tdb.c b/source/tdb/tdb.c new file mode 100644 index 00000000000..28425c29892 --- /dev/null +++ b/source/tdb/tdb.c @@ -0,0 +1,1742 @@ + /* + Unix SMB/Netbios implementation. + Version 3.0 + Samba database functions + Copyright (C) Andrew Tridgell 1999-2000 + Copyright (C) Luke Kenneth Casson Leighton 2000 + Copyright (C) Paul `Rusty' Russell 2000 + Copyright (C) Jeremy Allison 2000 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ +#ifdef STANDALONE +#if HAVE_CONFIG_H +#include <config.h> +#endif + +#include <stdlib.h> +#include <stdio.h> +#include <fcntl.h> +#include <unistd.h> +#include <string.h> +#include <fcntl.h> +#include <errno.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include "tdb.h" +#include "spinlock.h" +#else +#include "includes.h" +#endif + +#define TDB_MAGIC_FOOD "TDB file\n" +#define TDB_VERSION (0x26011967 + 6) +#define TDB_MAGIC (0x26011999U) +#define TDB_FREE_MAGIC (~TDB_MAGIC) +#define TDB_DEAD_MAGIC (0xFEE1DEAD) +#define TDB_ALIGNMENT 4 +#define MIN_REC_SIZE (2*sizeof(struct list_struct) + TDB_ALIGNMENT) +#define DEFAULT_HASH_SIZE 131 +#define TDB_PAGE_SIZE 0x2000 +#define FREELIST_TOP (sizeof(struct tdb_header)) +#define TDB_ALIGN(x,a) (((x) + (a)-1) & ~((a)-1)) +#define TDB_BYTEREV(x) (((((x)&0xff)<<24)|((x)&0xFF00)<<8)|(((x)>>8)&0xFF00)|((x)>>24)) +#define TDB_DEAD(r) ((r)->magic == TDB_DEAD_MAGIC) +#define TDB_BAD_MAGIC(r) ((r)->magic != TDB_MAGIC && !TDB_DEAD(r)) +#define TDB_HASH_TOP(hash) (FREELIST_TOP + (BUCKET(hash)+1)*sizeof(tdb_off)) + +/* NB assumes there is a local variable called "tdb" that is the + * current context, also takes doubly-parenthesized print-style + * argument. */ +#define TDB_LOG(x) (tdb->log_fn?((tdb->log_fn x),0) : 0) + +/* lock offsets */ +#define GLOBAL_LOCK 0 +#define ACTIVE_LOCK 4 + +#ifndef MAP_FILE +#define MAP_FILE 0 +#endif + +#ifndef MAP_FAILED +#define MAP_FAILED ((void *)-1) +#endif + +#define BUCKET(hash) ((hash) % tdb->header.hash_size) +TDB_DATA tdb_null; + +/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */ +static TDB_CONTEXT *tdbs = NULL; + +static void tdb_munmap(TDB_CONTEXT *tdb) +{ + if (tdb->flags & TDB_INTERNAL) + return; + +#ifdef HAVE_MMAP + if (tdb->map_ptr) + munmap(tdb->map_ptr, tdb->map_size); +#endif + tdb->map_ptr = NULL; +} + +static void tdb_mmap(TDB_CONTEXT *tdb) +{ + if (tdb->flags & TDB_INTERNAL) + return; + +#ifdef HAVE_MMAP + if (!(tdb->flags & TDB_NOMMAP)) { + tdb->map_ptr = mmap(NULL, tdb->map_size, + PROT_READ|(tdb->read_only? 0:PROT_WRITE), + MAP_SHARED|MAP_FILE, tdb->fd, 0); + + /* + * NB. When mmap fails it returns MAP_FAILED *NOT* NULL !!!! + */ + + if (tdb->map_ptr == MAP_FAILED) { + tdb->map_ptr = NULL; + TDB_LOG((tdb, 2, "tdb_mmap failed for size %d (%s)\n", + tdb->map_size, strerror(errno))); + } + } else { + tdb->map_ptr = NULL; + } +#else + tdb->map_ptr = NULL; +#endif +} + +/* Endian conversion: we only ever deal with 4 byte quantities */ +static void *convert(void *buf, u32 size) +{ + u32 i, *p = buf; + for (i = 0; i < size / 4; i++) + p[i] = TDB_BYTEREV(p[i]); + return buf; +} +#define DOCONV() (tdb->flags & TDB_CONVERT) +#define CONVERT(x) (DOCONV() ? convert(&x, sizeof(x)) : &x) + +/* the body of the database is made of one list_struct for the free space + plus a separate data list for each hash value */ +struct list_struct { + tdb_off next; /* offset of the next record in the list */ + tdb_len rec_len; /* total byte length of record */ + tdb_len key_len; /* byte length of key */ + tdb_len data_len; /* byte length of data */ + u32 full_hash; /* the full 32 bit hash of the key */ + u32 magic; /* try to catch errors */ + /* the following union is implied: + union { + char record[rec_len]; + struct { + char key[key_len]; + char data[data_len]; + } + u32 totalsize; (tailer) + } + */ +}; + +/* a byte range locking function - return 0 on success + this functions locks/unlocks 1 byte at the specified offset. + + On error, errno is also set so that errors are passed back properly + through tdb_open(). */ +static int tdb_brlock(TDB_CONTEXT *tdb, tdb_off offset, + int rw_type, int lck_type, int probe) +{ + struct flock fl; + + if (tdb->flags & TDB_NOLOCK) + return 0; + if (tdb->read_only) { + errno = EACCES; + return -1; + } + + fl.l_type = rw_type; + fl.l_whence = SEEK_SET; + fl.l_start = offset; + fl.l_len = 1; + fl.l_pid = 0; + + if (fcntl(tdb->fd,lck_type,&fl) == -1) { + if (!probe) { + TDB_LOG((tdb, 5,"tdb_brlock failed (fd=%d) at offset %d rw_type=%d lck_type=%d\n", + tdb->fd, offset, rw_type, lck_type)); + } + /* errno set by fcntl */ + return TDB_ERRCODE(TDB_ERR_LOCK, -1); + } + return 0; +} + +/* lock a list in the database. list -1 is the alloc list */ +static int tdb_lock(TDB_CONTEXT *tdb, int list, int ltype) +{ + if (list < -1 || list >= (int)tdb->header.hash_size) { + TDB_LOG((tdb, 0,"tdb_lock: invalid list %d for ltype=%d\n", + list, ltype)); + return -1; + } + if (tdb->flags & TDB_NOLOCK) + return 0; + + /* Since fcntl locks don't nest, we do a lock for the first one, + and simply bump the count for future ones */ + if (tdb->locked[list+1].count == 0) { + if (!tdb->read_only && tdb->header.rwlocks) { + if (tdb_spinlock(tdb, list, ltype)) { + TDB_LOG((tdb, 0, "tdb_lock spinlock failed on list ltype=%d\n", + list, ltype)); + return -1; + } + } else if (tdb_brlock(tdb,FREELIST_TOP+4*list,ltype,F_SETLKW, 0)) { + TDB_LOG((tdb, 0,"tdb_lock failed on list %d ltype=%d (%s)\n", + list, ltype, strerror(errno))); + return -1; + } + tdb->locked[list+1].ltype = ltype; + } + tdb->locked[list+1].count++; + return 0; +} + +/* unlock the database: returns void because it's too late for errors. */ +static void tdb_unlock(TDB_CONTEXT *tdb, int list, int ltype) +{ + if (tdb->flags & TDB_NOLOCK) + return; + + /* Sanity checks */ + if (list < -1 || list >= (int)tdb->header.hash_size) + return; + if (tdb->locked[list+1].count==0) + return; + + if (tdb->locked[list+1].count == 1) { + /* Down to last nested lock: unlock underneath */ + if (!tdb->read_only && tdb->header.rwlocks) + tdb_spinunlock(tdb, list, ltype); + else + tdb_brlock(tdb, FREELIST_TOP+4*list, F_UNLCK, F_SETLKW, 0); + } + tdb->locked[list+1].count--; +} + +/* This is based on the hash agorithm from gdbm */ +static u32 tdb_hash(TDB_DATA *key) +{ + u32 value; /* Used to compute the hash value. */ + u32 i; /* Used to cycle through random values. */ + + /* Set the initial value from the key size. */ + for (value = 0x238F13AF * key->dsize, i=0; i < key->dsize; i++) + value = (value + (key->dptr[i] << (i*5 % 24))); + + return (1103515243 * value + 12345); +} + +/* check for an out of bounds access - if it is out of bounds then + see if the database has been expanded by someone else and expand + if necessary + note that "len" is the minimum length needed for the db +*/ +static int tdb_oob(TDB_CONTEXT *tdb, tdb_off len, int probe) +{ + struct stat st; + if (len <= tdb->map_size) + return 0; + if (tdb->flags & TDB_INTERNAL) { + if (!probe) { + TDB_LOG((tdb, 0,"tdb_oob len %d beyond internal malloc size %d\n", + (int)len, (int)tdb->map_size)); + } + return TDB_ERRCODE(TDB_ERR_IO, -1); + } + + if (fstat(tdb->fd, &st) == -1) + return TDB_ERRCODE(TDB_ERR_IO, -1); + + if (st.st_size < (size_t)len) { + if (!probe) { + TDB_LOG((tdb, 0,"tdb_oob len %d beyond eof at %d\n", + (int)len, (int)st.st_size)); + } + return TDB_ERRCODE(TDB_ERR_IO, -1); + } + + /* Unmap, update size, remap */ + tdb_munmap(tdb); + tdb->map_size = st.st_size; + tdb_mmap(tdb); + return 0; +} + +/* write a lump of data at a specified offset */ +static int tdb_write(TDB_CONTEXT *tdb, tdb_off off, void *buf, tdb_len len) +{ + if (tdb_oob(tdb, off + len, 0) != 0) + return -1; + + if (tdb->map_ptr) + memcpy(off + (char *)tdb->map_ptr, buf, len); +#ifdef HAVE_PWRITE + else if (pwrite(tdb->fd, buf, len, off) != (ssize_t)len) { +#else + else if (lseek(tdb->fd, off, SEEK_SET) != off + || write(tdb->fd, buf, len) != (ssize_t)len) { +#endif + TDB_LOG((tdb, 0,"tdb_write failed at %d len=%d (%s)\n", + off, len, strerror(errno))); + return TDB_ERRCODE(TDB_ERR_IO, -1); + } + return 0; +} + +/* read a lump of data at a specified offset, maybe convert */ +static int tdb_read(TDB_CONTEXT *tdb,tdb_off off,void *buf,tdb_len len,int cv) +{ + if (tdb_oob(tdb, off + len, 0) != 0) + return -1; + + if (tdb->map_ptr) + memcpy(buf, off + (char *)tdb->map_ptr, len); +#ifdef HAVE_PREAD + else if (pread(tdb->fd, buf, len, off) != (ssize_t)len) { +#else + else if (lseek(tdb->fd, off, SEEK_SET) != off + || read(tdb->fd, buf, len) != (ssize_t)len) { +#endif + TDB_LOG((tdb, 0,"tdb_read failed at %d len=%d (%s)\n", + off, len, strerror(errno))); + return TDB_ERRCODE(TDB_ERR_IO, -1); + } + if (cv) + convert(buf, len); + return 0; +} + +/* read a lump of data, allocating the space for it */ +static char *tdb_alloc_read(TDB_CONTEXT *tdb, tdb_off offset, tdb_len len) +{ + char *buf; + + if (!(buf = malloc(len))) { + TDB_LOG((tdb, 0,"tdb_alloc_read malloc failed len=%d (%s)\n", + len, strerror(errno))); + return TDB_ERRCODE(TDB_ERR_OOM, buf); + } + if (tdb_read(tdb, offset, buf, len, 0) == -1) { + free(buf); + return NULL; + } + return buf; +} + +/* read/write a tdb_off */ +static int ofs_read(TDB_CONTEXT *tdb, tdb_off offset, tdb_off *d) +{ + return tdb_read(tdb, offset, (char*)d, sizeof(*d), DOCONV()); +} +static int ofs_write(TDB_CONTEXT *tdb, tdb_off offset, tdb_off *d) +{ + tdb_off off = *d; + return tdb_write(tdb, offset, CONVERT(off), sizeof(*d)); +} + +/* read/write a record */ +static int rec_read(TDB_CONTEXT *tdb, tdb_off offset, struct list_struct *rec) +{ + if (tdb_read(tdb, offset, rec, sizeof(*rec),DOCONV()) == -1) + return -1; + if (TDB_BAD_MAGIC(rec)) { + TDB_LOG((tdb, 0,"rec_read bad magic 0x%x at offset=%d\n", rec->magic, offset)); + return TDB_ERRCODE(TDB_ERR_CORRUPT, -1); + } + return tdb_oob(tdb, rec->next+sizeof(*rec), 0); +} +static int rec_write(TDB_CONTEXT *tdb, tdb_off offset, struct list_struct *rec) +{ + struct list_struct r = *rec; + return tdb_write(tdb, offset, CONVERT(r), sizeof(r)); +} + +/* read a freelist record and check for simple errors */ +static int rec_free_read(TDB_CONTEXT *tdb, tdb_off off, struct list_struct *rec) +{ + if (tdb_read(tdb, off, rec, sizeof(*rec),DOCONV()) == -1) + return -1; + if (rec->magic != TDB_FREE_MAGIC) { + TDB_LOG((tdb, 0,"rec_free_read bad magic 0x%x at offset=%d\n", + rec->magic, off)); + return TDB_ERRCODE(TDB_ERR_CORRUPT, -1); + } + if (tdb_oob(tdb, rec->next+sizeof(*rec), 0) != 0) + return -1; + return 0; +} + +/* update a record tailer (must hold allocation lock) */ +static int update_tailer(TDB_CONTEXT *tdb, tdb_off offset, + const struct list_struct *rec) +{ + tdb_off totalsize; + + /* Offset of tailer from record header */ + totalsize = sizeof(*rec) + rec->rec_len; + return ofs_write(tdb, offset + totalsize - sizeof(tdb_off), + &totalsize); +} + +static tdb_off tdb_dump_record(TDB_CONTEXT *tdb, tdb_off offset) +{ + struct list_struct rec; + tdb_off tailer_ofs, tailer; + + if (tdb_read(tdb, offset, (char *)&rec, sizeof(rec), DOCONV()) == -1) { + printf("ERROR: failed to read record at %u\n", offset); + return 0; + } + + printf(" rec: offset=%u next=%d rec_len=%d key_len=%d data_len=%d full_hash=0x%x magic=0x%x\n", + offset, rec.next, rec.rec_len, rec.key_len, rec.data_len, rec.full_hash, rec.magic); + + tailer_ofs = offset + sizeof(rec) + rec.rec_len - sizeof(tdb_off); + if (ofs_read(tdb, tailer_ofs, &tailer) == -1) { + printf("ERROR: failed to read tailer at %u\n", tailer_ofs); + return rec.next; + } + + if (tailer != rec.rec_len + sizeof(rec)) { + printf("ERROR: tailer does not match record! tailer=%u totalsize=%u\n", tailer, rec.rec_len + sizeof(rec)); + } + return rec.next; +} + +static void tdb_dump_chain(TDB_CONTEXT *tdb, int i) +{ + tdb_off rec_ptr, top; + + top = TDB_HASH_TOP(i); + + tdb_lock(tdb, i, F_WRLCK); + + if (ofs_read(tdb, top, &rec_ptr) == -1) { + tdb_unlock(tdb, i, F_WRLCK); + return; + } + + if (rec_ptr) + printf("hash=%d\n", i); + + while (rec_ptr) { + rec_ptr = tdb_dump_record(tdb, rec_ptr); + } + tdb_unlock(tdb, i, F_WRLCK); +} + +void tdb_dump_all(TDB_CONTEXT *tdb) +{ + int i; + for (i=0;i<tdb->header.hash_size;i++) { + tdb_dump_chain(tdb, i); + } + printf("freelist:\n"); + tdb_dump_chain(tdb, -1); +} + +void tdb_printfreelist(TDB_CONTEXT *tdb) +{ + long total_free = 0; + tdb_off offset, rec_ptr, last_ptr; + struct list_struct rec; + + tdb_lock(tdb, -1, F_WRLCK); + + last_ptr = 0; + offset = FREELIST_TOP; + + /* read in the freelist top */ + if (ofs_read(tdb, offset, &rec_ptr) == -1) { + return; + } + + printf("freelist top=[0x%08x]\n", rec_ptr ); + while (rec_ptr) { + if (tdb_read(tdb, rec_ptr, (char *)&rec, sizeof(rec), DOCONV()) == -1) { + return; + } + + if (rec.magic != TDB_FREE_MAGIC) { + printf("bad magic 0x%08x in free list\n", rec.magic); + return; + } + + printf("entry offset=[0x%08x], rec.rec_len = [0x%08x (%d)]\n", rec.next, rec.rec_len, rec.rec_len ); + total_free += rec.rec_len; + + /* move to the next record */ + rec_ptr = rec.next; + } + printf("total rec_len = [0x%08x (%d)]\n", (int)total_free, + (int)total_free); + + tdb_unlock(tdb, -1, F_WRLCK); +} + +/* Remove an element from the freelist. Must have alloc lock. */ +static int remove_from_freelist(TDB_CONTEXT *tdb, tdb_off off, tdb_off next) +{ + tdb_off last_ptr, i; + + /* read in the freelist top */ + last_ptr = FREELIST_TOP; + while (ofs_read(tdb, last_ptr, &i) != -1 && i != 0) { + if (i == off) { + /* We've found it! */ + return ofs_write(tdb, last_ptr, &next); + } + /* Follow chain (next offset is at start of record) */ + last_ptr = i; + } + TDB_LOG((tdb, 0,"remove_from_freelist: not on list at off=%d\n", off)); + return TDB_ERRCODE(TDB_ERR_CORRUPT, -1); +} + +/* Add an element into the freelist. Merge adjacent records if + neccessary. */ +static int tdb_free(TDB_CONTEXT *tdb, tdb_off offset, struct list_struct *rec) +{ + tdb_off right, left; + + /* Allocation and tailer lock */ + if (tdb_lock(tdb, -1, F_WRLCK) != 0) + return -1; + + /* set an initial tailer, so if we fail we don't leave a bogus record */ + update_tailer(tdb, offset, rec); + + /* Look right first (I'm an Australian, dammit) */ + right = offset + sizeof(*rec) + rec->rec_len; + if (right + sizeof(*rec) <= tdb->map_size) { + struct list_struct r; + + if (tdb_read(tdb, right, &r, sizeof(r), DOCONV()) == -1) { + TDB_LOG((tdb, 0, "tdb_free: right read failed at %u\n", right)); + goto left; + } + + /* If it's free, expand to include it. */ + if (r.magic == TDB_FREE_MAGIC) { + if (remove_from_freelist(tdb, right, r.next) == -1) { + TDB_LOG((tdb, 0, "tdb_free: right free failed at %u\n", right)); + goto left; + } + rec->rec_len += sizeof(r) + r.rec_len; + } + } + +left: + /* Look left */ + left = offset - sizeof(tdb_off); + if (left > TDB_HASH_TOP(tdb->header.hash_size-1)) { + struct list_struct l; + tdb_off leftsize; + + /* Read in tailer and jump back to header */ + if (ofs_read(tdb, left, &leftsize) == -1) { + TDB_LOG((tdb, 0, "tdb_free: left offset read failed at %u\n", left)); + goto update; + } + left = offset - leftsize; + + /* Now read in record */ + if (tdb_read(tdb, left, &l, sizeof(l), DOCONV()) == -1) { + TDB_LOG((tdb, 0, "tdb_free: left read failed at %u (%u)\n", left, leftsize)); + goto update; + } + + /* If it's free, expand to include it. */ + if (l.magic == TDB_FREE_MAGIC) { + if (remove_from_freelist(tdb, left, l.next) == -1) { + TDB_LOG((tdb, 0, "tdb_free: left free failed at %u\n", left)); + goto update; + } else { + offset = left; + rec->rec_len += leftsize; + } + } + } + +update: + if (update_tailer(tdb, offset, rec) == -1) { + TDB_LOG((tdb, 0, "tdb_free: update_tailer failed at %u\n", offset)); + goto fail; + } + + /* Now, prepend to free list */ + rec->magic = TDB_FREE_MAGIC; + + if (ofs_read(tdb, FREELIST_TOP, &rec->next) == -1 || + rec_write(tdb, offset, rec) == -1 || + ofs_write(tdb, FREELIST_TOP, &offset) == -1) { + TDB_LOG((tdb, 0, "tdb_free record write failed at offset=%d\n", offset)); + goto fail; + } + + /* And we're done. */ + tdb_unlock(tdb, -1, F_WRLCK); + return 0; + + fail: + tdb_unlock(tdb, -1, F_WRLCK); + return -1; +} + + +/* expand a file. we prefer to use ftruncate, as that is what posix + says to use for mmap expansion */ +static int expand_file(TDB_CONTEXT *tdb, tdb_off size, tdb_off addition) +{ + char buf[1024]; +#if HAVE_FTRUNCATE_EXTEND + if (ftruncate(tdb->fd, size+addition) != 0) { + TDB_LOG((tdb, 0, "expand_file ftruncate to %d failed (%s)\n", + size+addition, strerror(errno))); + return -1; + } +#else + char b = 0; + +#ifdef HAVE_PWRITE + if (pwrite(tdb->fd, &b, 1, (size+addition) - 1) != 1) { +#else + if (lseek(tdb->fd, (size+addition) - 1, SEEK_SET) != (size+addition) - 1 || + write(tdb->fd, &b, 1) != 1) { +#endif + TDB_LOG((tdb, 0, "expand_file to %d failed (%s)\n", + size+addition, strerror(errno))); + return -1; + } +#endif + + /* now fill the file with something. This ensures that the file isn't sparse, which would be + very bad if we ran out of disk. This must be done with write, not via mmap */ + memset(buf, 0x42, sizeof(buf)); + while (addition) { + int n = addition>sizeof(buf)?sizeof(buf):addition; +#ifdef HAVE_PWRITE + int ret = pwrite(tdb->fd, buf, n, size); +#else + int ret; + if (lseek(tdb->fd, size, SEEK_SET) != size) + return -1; + ret = write(tdb->fd, buf, n); +#endif + if (ret != n) { + TDB_LOG((tdb, 0, "expand_file write of %d failed (%s)\n", + n, strerror(errno))); + return -1; + } + addition -= n; + size += n; + } + return 0; +} + + +/* expand the database at least size bytes by expanding the underlying + file and doing the mmap again if necessary */ +static int tdb_expand(TDB_CONTEXT *tdb, tdb_off size) +{ + struct list_struct rec; + tdb_off offset; + + if (tdb_lock(tdb, -1, F_WRLCK) == -1) { + TDB_LOG((tdb, 0, "lock failed in tdb_expand\n")); + return -1; + } + + /* must know about any previous expansions by another process */ + tdb_oob(tdb, tdb->map_size + 1, 1); + + /* always make room for at least 10 more records, and round + the database up to a multiple of TDB_PAGE_SIZE */ + size = TDB_ALIGN(tdb->map_size + size*10, TDB_PAGE_SIZE) - tdb->map_size; + + if (!(tdb->flags & TDB_INTERNAL)) + tdb_munmap(tdb); + + /* + * We must ensure the file is unmapped before doing this + * to ensure consistency with systems like OpenBSD where + * writes and mmaps are not consistent. + */ + + /* expand the file itself */ + if (!(tdb->flags & TDB_INTERNAL)) { + if (expand_file(tdb, tdb->map_size, size) != 0) + goto fail; + } + + tdb->map_size += size; + + if (tdb->flags & TDB_INTERNAL) + tdb->map_ptr = realloc(tdb->map_ptr, tdb->map_size); + else { + /* + * We must ensure the file is remapped before adding the space + * to ensure consistency with systems like OpenBSD where + * writes and mmaps are not consistent. + */ + + /* We're ok if the mmap fails as we'll fallback to read/write */ + tdb_mmap(tdb); + } + + /* form a new freelist record */ + memset(&rec,'\0',sizeof(rec)); + rec.rec_len = size - sizeof(rec); + + /* link it into the free list */ + offset = tdb->map_size - size; + if (tdb_free(tdb, offset, &rec) == -1) + goto fail; + + tdb_unlock(tdb, -1, F_WRLCK); + return 0; + fail: + tdb_unlock(tdb, -1, F_WRLCK); + return -1; +} + +/* allocate some space from the free list. The offset returned points + to a unconnected list_struct within the database with room for at + least length bytes of total data + + 0 is returned if the space could not be allocated + */ +static tdb_off tdb_allocate(TDB_CONTEXT *tdb, tdb_len length, + struct list_struct *rec) +{ + tdb_off rec_ptr, last_ptr, newrec_ptr; + struct list_struct newrec; + + if (tdb_lock(tdb, -1, F_WRLCK) == -1) + return 0; + + /* Extra bytes required for tailer */ + length += sizeof(tdb_off); + + again: + last_ptr = FREELIST_TOP; + + /* read in the freelist top */ + if (ofs_read(tdb, FREELIST_TOP, &rec_ptr) == -1) + goto fail; + + /* keep looking until we find a freelist record big enough */ + while (rec_ptr) { + if (rec_free_read(tdb, rec_ptr, rec) == -1) + goto fail; + + if (rec->rec_len >= length) { + /* found it - now possibly split it up */ + if (rec->rec_len > length + MIN_REC_SIZE) { + /* Length of left piece */ + length = TDB_ALIGN(length, TDB_ALIGNMENT); + + /* Right piece to go on free list */ + newrec.rec_len = rec->rec_len + - (sizeof(*rec) + length); + newrec_ptr = rec_ptr + sizeof(*rec) + length; + + /* And left record is shortened */ + rec->rec_len = length; + } else + newrec_ptr = 0; + + /* Remove allocated record from the free list */ + if (ofs_write(tdb, last_ptr, &rec->next) == -1) + goto fail; + + /* Update header: do this before we drop alloc + lock, otherwise tdb_free() might try to + merge with us, thinking we're free. + (Thanks Jeremy Allison). */ + rec->magic = TDB_MAGIC; + if (rec_write(tdb, rec_ptr, rec) == -1) + goto fail; + + /* Did we create new block? */ + if (newrec_ptr) { + /* Update allocated record tailer (we + shortened it). */ + if (update_tailer(tdb, rec_ptr, rec) == -1) + goto fail; + + /* Free new record */ + if (tdb_free(tdb, newrec_ptr, &newrec) == -1) + goto fail; + } + + /* all done - return the new record offset */ + tdb_unlock(tdb, -1, F_WRLCK); + return rec_ptr; + } + /* move to the next record */ + last_ptr = rec_ptr; + rec_ptr = rec->next; + } + /* we didn't find enough space. See if we can expand the + database and if we can then try again */ + if (tdb_expand(tdb, length + sizeof(*rec)) == 0) + goto again; + fail: + tdb_unlock(tdb, -1, F_WRLCK); + return 0; +} + +/* initialise a new database with a specified hash size */ +static int tdb_new_database(TDB_CONTEXT *tdb, int hash_size) +{ + struct tdb_header *newdb; + int size, ret = -1; + + /* We make it up in memory, then write it out if not internal */ + size = sizeof(struct tdb_header) + (hash_size+1)*sizeof(tdb_off); + if (!(newdb = calloc(size, 1))) + return TDB_ERRCODE(TDB_ERR_OOM, -1); + + /* Fill in the header */ + newdb->version = TDB_VERSION; + newdb->hash_size = hash_size; +#ifdef USE_SPINLOCKS + newdb->rwlocks = size; +#endif + if (tdb->flags & TDB_INTERNAL) { + tdb->map_size = size; + tdb->map_ptr = (char *)newdb; + memcpy(&tdb->header, newdb, sizeof(tdb->header)); + /* Convert the `ondisk' version if asked. */ + CONVERT(*newdb); + return 0; + } + if (lseek(tdb->fd, 0, SEEK_SET) == -1) + goto fail; + + if (ftruncate(tdb->fd, 0) == -1) + goto fail; + + /* This creates an endian-converted header, as if read from disk */ + CONVERT(*newdb); + memcpy(&tdb->header, newdb, sizeof(tdb->header)); + /* Don't endian-convert the magic food! */ + memcpy(newdb->magic_food, TDB_MAGIC_FOOD, strlen(TDB_MAGIC_FOOD)+1); + if (write(tdb->fd, newdb, size) != size) + ret = -1; + else + ret = tdb_create_rwlocks(tdb->fd, hash_size); + + fail: + free(newdb); + return ret; +} + +/* Returns 0 on fail. On success, return offset of record, and fills + in rec */ +static tdb_off tdb_find(TDB_CONTEXT *tdb, TDB_DATA key, u32 hash, + struct list_struct *r) +{ + tdb_off rec_ptr; + + /* read in the hash top */ + if (ofs_read(tdb, TDB_HASH_TOP(hash), &rec_ptr) == -1) + return 0; + + /* keep looking until we find the right record */ + while (rec_ptr) { + if (rec_read(tdb, rec_ptr, r) == -1) + return 0; + + if (!TDB_DEAD(r) && hash==r->full_hash && key.dsize==r->key_len) { + char *k; + /* a very likely hit - read the key */ + k = tdb_alloc_read(tdb, rec_ptr + sizeof(*r), + r->key_len); + if (!k) + return 0; + + if (memcmp(key.dptr, k, key.dsize) == 0) { + free(k); + return rec_ptr; + } + free(k); + } + rec_ptr = r->next; + } + return TDB_ERRCODE(TDB_ERR_NOEXIST, 0); +} + +/* If they do lockkeys, check that this hash is one they locked */ +static int tdb_keylocked(TDB_CONTEXT *tdb, u32 hash) +{ + u32 i; + if (!tdb->lockedkeys) + return 1; + for (i = 0; i < tdb->lockedkeys[0]; i++) + if (tdb->lockedkeys[i+1] == hash) + return 1; + return TDB_ERRCODE(TDB_ERR_NOLOCK, 0); +} + +/* As tdb_find, but if you succeed, keep the lock */ +static tdb_off tdb_find_lock(TDB_CONTEXT *tdb, TDB_DATA key, int locktype, + struct list_struct *rec) +{ + u32 hash, rec_ptr; + + hash = tdb_hash(&key); + if (!tdb_keylocked(tdb, hash)) + return 0; + if (tdb_lock(tdb, BUCKET(hash), locktype) == -1) + return 0; + if (!(rec_ptr = tdb_find(tdb, key, hash, rec))) + tdb_unlock(tdb, BUCKET(hash), locktype); + return rec_ptr; +} + +enum TDB_ERROR tdb_error(TDB_CONTEXT *tdb) +{ + return tdb->ecode; +} + +static struct tdb_errname { + enum TDB_ERROR ecode; const char *estring; +} emap[] = { {TDB_SUCCESS, "Success"}, + {TDB_ERR_CORRUPT, "Corrupt database"}, + {TDB_ERR_IO, "IO Error"}, + {TDB_ERR_LOCK, "Locking error"}, + {TDB_ERR_OOM, "Out of memory"}, + {TDB_ERR_EXISTS, "Record exists"}, + {TDB_ERR_NOLOCK, "Lock exists on other keys"}, + {TDB_ERR_NOEXIST, "Record does not exist"} }; + +/* Error string for the last tdb error */ +const char *tdb_errorstr(TDB_CONTEXT *tdb) +{ + u32 i; + for (i = 0; i < sizeof(emap) / sizeof(struct tdb_errname); i++) + if (tdb->ecode == emap[i].ecode) + return emap[i].estring; + return "Invalid error code"; +} + +/* update an entry in place - this only works if the new data size + is <= the old data size and the key exists. + on failure return -1 +*/ +static int tdb_update(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf) +{ + struct list_struct rec; + tdb_off rec_ptr; + int ret = -1; + + /* find entry */ + if (!(rec_ptr = tdb_find_lock(tdb, key, F_WRLCK, &rec))) + return -1; + + /* must be long enough key, data and tailer */ + if (rec.rec_len < key.dsize + dbuf.dsize + sizeof(tdb_off)) { + tdb->ecode = TDB_SUCCESS; /* Not really an error */ + goto out; + } + + if (tdb_write(tdb, rec_ptr + sizeof(rec) + rec.key_len, + dbuf.dptr, dbuf.dsize) == -1) + goto out; + + if (dbuf.dsize != rec.data_len) { + /* update size */ + rec.data_len = dbuf.dsize; + ret = rec_write(tdb, rec_ptr, &rec); + } else + ret = 0; + out: + tdb_unlock(tdb, BUCKET(rec.full_hash), F_WRLCK); + return ret; +} + +/* find an entry in the database given a key */ +TDB_DATA tdb_fetch(TDB_CONTEXT *tdb, TDB_DATA key) +{ + tdb_off rec_ptr; + struct list_struct rec; + TDB_DATA ret; + + /* find which hash bucket it is in */ + if (!(rec_ptr = tdb_find_lock(tdb,key,F_RDLCK,&rec))) + return tdb_null; + + ret.dptr = tdb_alloc_read(tdb, rec_ptr + sizeof(rec) + rec.key_len, + rec.data_len); + ret.dsize = rec.data_len; + tdb_unlock(tdb, BUCKET(rec.full_hash), F_RDLCK); + return ret; +} + +/* check if an entry in the database exists + + note that 1 is returned if the key is found and 0 is returned if not found + this doesn't match the conventions in the rest of this module, but is + compatible with gdbm +*/ +int tdb_exists(TDB_CONTEXT *tdb, TDB_DATA key) +{ + struct list_struct rec; + + if (tdb_find_lock(tdb, key, F_RDLCK, &rec) == 0) + return 0; + tdb_unlock(tdb, BUCKET(rec.full_hash), F_RDLCK); + return 1; +} + +/* record lock stops delete underneath */ +static int lock_record(TDB_CONTEXT *tdb, tdb_off off) +{ + return off ? tdb_brlock(tdb, off, F_RDLCK, F_SETLKW, 0) : 0; +} +/* + Write locks override our own fcntl readlocks, so check it here. + Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not + an error to fail to get the lock here. +*/ + +static int write_lock_record(TDB_CONTEXT *tdb, tdb_off off) +{ + struct tdb_traverse_lock *i; + for (i = &tdb->travlocks; i; i = i->next) + if (i->off == off) + return -1; + return tdb_brlock(tdb, off, F_WRLCK, F_SETLK, 1); +} + +/* + Note this is meant to be F_SETLK, *not* F_SETLKW, as it's not + an error to fail to get the lock here. +*/ + +static int write_unlock_record(TDB_CONTEXT *tdb, tdb_off off) +{ + return tdb_brlock(tdb, off, F_UNLCK, F_SETLK, 0); +} +/* fcntl locks don't stack: avoid unlocking someone else's */ +static int unlock_record(TDB_CONTEXT *tdb, tdb_off off) +{ + struct tdb_traverse_lock *i; + u32 count = 0; + + if (off == 0) + return 0; + for (i = &tdb->travlocks; i; i = i->next) + if (i->off == off) + count++; + return (count == 1 ? tdb_brlock(tdb, off, F_UNLCK, F_SETLKW, 0) : 0); +} + +/* actually delete an entry in the database given the offset */ +static int do_delete(TDB_CONTEXT *tdb, tdb_off rec_ptr, struct list_struct*rec) +{ + tdb_off last_ptr, i; + struct list_struct lastrec; + + if (tdb->read_only) return -1; + + if (write_lock_record(tdb, rec_ptr) == -1) { + /* Someone traversing here: mark it as dead */ + rec->magic = TDB_DEAD_MAGIC; + return rec_write(tdb, rec_ptr, rec); + } + write_unlock_record(tdb, rec_ptr); + + /* find previous record in hash chain */ + if (ofs_read(tdb, TDB_HASH_TOP(rec->full_hash), &i) == -1) + return -1; + for (last_ptr = 0; i != rec_ptr; last_ptr = i, i = lastrec.next) + if (rec_read(tdb, i, &lastrec) == -1) + return -1; + + /* unlink it: next ptr is at start of record. */ + if (last_ptr == 0) + last_ptr = TDB_HASH_TOP(rec->full_hash); + if (ofs_write(tdb, last_ptr, &rec->next) == -1) + return -1; + + /* recover the space */ + if (tdb_free(tdb, rec_ptr, rec) == -1) + return -1; + return 0; +} + +/* Uses traverse lock: 0 = finish, -1 = error, other = record offset */ +static int tdb_next_lock(TDB_CONTEXT *tdb, struct tdb_traverse_lock *tlock, + struct list_struct *rec) +{ + int want_next = (tlock->off != 0); + + /* No traversal allows if you've called tdb_lockkeys() */ + if (tdb->lockedkeys) + return TDB_ERRCODE(TDB_ERR_NOLOCK, -1); + + /* Lock each chain from the start one. */ + for (; tlock->hash < tdb->header.hash_size; tlock->hash++) { + if (tdb_lock(tdb, tlock->hash, F_WRLCK) == -1) + return -1; + + /* No previous record? Start at top of chain. */ + if (!tlock->off) { + if (ofs_read(tdb, TDB_HASH_TOP(tlock->hash), + &tlock->off) == -1) + goto fail; + } else { + /* Otherwise unlock the previous record. */ + unlock_record(tdb, tlock->off); + } + + if (want_next) { + /* We have offset of old record: grab next */ + if (rec_read(tdb, tlock->off, rec) == -1) + goto fail; + tlock->off = rec->next; + } + + /* Iterate through chain */ + while( tlock->off) { + tdb_off current; + if (rec_read(tdb, tlock->off, rec) == -1) + goto fail; + if (!TDB_DEAD(rec)) { + /* Woohoo: we found one! */ + lock_record(tdb, tlock->off); + return tlock->off; + } + /* Try to clean dead ones from old traverses */ + current = tlock->off; + tlock->off = rec->next; + do_delete(tdb, current, rec); + } + tdb_unlock(tdb, tlock->hash, F_WRLCK); + want_next = 0; + } + /* We finished iteration without finding anything */ + return TDB_ERRCODE(TDB_SUCCESS, 0); + + fail: + tlock->off = 0; + tdb_unlock(tdb, tlock->hash, F_WRLCK); + return -1; +} + +/* traverse the entire database - calling fn(tdb, key, data) on each element. + return -1 on error or the record count traversed + if fn is NULL then it is not called + a non-zero return value from fn() indicates that the traversal should stop + */ +int tdb_traverse(TDB_CONTEXT *tdb, tdb_traverse_func fn, void *state) +{ + TDB_DATA key, dbuf; + struct list_struct rec; + struct tdb_traverse_lock tl = { NULL, 0, 0 }; + int ret, count = 0; + + /* This was in the initializaton, above, but the IRIX compiler + * did not like it. crh + */ + tl.next = tdb->travlocks.next; + + /* fcntl locks don't stack: beware traverse inside traverse */ + tdb->travlocks.next = &tl; + + /* tdb_next_lock places locks on the record returned, and its chain */ + while ((ret = tdb_next_lock(tdb, &tl, &rec)) > 0) { + count++; + /* now read the full record */ + key.dptr = tdb_alloc_read(tdb, tl.off + sizeof(rec), + rec.key_len + rec.data_len); + if (!key.dptr) { + tdb_unlock(tdb, tl.hash, F_WRLCK); + unlock_record(tdb, tl.off); + tdb->travlocks.next = tl.next; + return -1; + } + key.dsize = rec.key_len; + dbuf.dptr = key.dptr + rec.key_len; + dbuf.dsize = rec.data_len; + + /* Drop chain lock, call out */ + tdb_unlock(tdb, tl.hash, F_WRLCK); + if (fn && fn(tdb, key, dbuf, state)) { + /* They want us to terminate traversal */ + unlock_record(tdb, tl.off); + tdb->travlocks.next = tl.next; + free(key.dptr); + return count; + } + free(key.dptr); + } + tdb->travlocks.next = tl.next; + if (ret < 0) + return -1; + else + return count; +} + +/* find the first entry in the database and return its key */ +TDB_DATA tdb_firstkey(TDB_CONTEXT *tdb) +{ + TDB_DATA key; + struct list_struct rec; + + /* release any old lock */ + unlock_record(tdb, tdb->travlocks.off); + tdb->travlocks.off = tdb->travlocks.hash = 0; + + if (tdb_next_lock(tdb, &tdb->travlocks, &rec) <= 0) + return tdb_null; + /* now read the key */ + key.dsize = rec.key_len; + key.dptr =tdb_alloc_read(tdb,tdb->travlocks.off+sizeof(rec),key.dsize); + tdb_unlock(tdb, BUCKET(tdb->travlocks.hash), F_WRLCK); + return key; +} + +/* find the next entry in the database, returning its key */ +TDB_DATA tdb_nextkey(TDB_CONTEXT *tdb, TDB_DATA oldkey) +{ + u32 oldhash; + TDB_DATA key = tdb_null; + struct list_struct rec; + char *k = NULL; + + /* Is locked key the old key? If so, traverse will be reliable. */ + if (tdb->travlocks.off) { + if (tdb_lock(tdb,tdb->travlocks.hash,F_WRLCK)) + return tdb_null; + if (rec_read(tdb, tdb->travlocks.off, &rec) == -1 + || !(k = tdb_alloc_read(tdb,tdb->travlocks.off+sizeof(rec), + rec.key_len)) + || memcmp(k, oldkey.dptr, oldkey.dsize) != 0) { + /* No, it wasn't: unlock it and start from scratch */ + unlock_record(tdb, tdb->travlocks.off); + tdb_unlock(tdb, tdb->travlocks.hash, F_WRLCK); + tdb->travlocks.off = 0; + } + + if (k) + free(k); + } + + if (!tdb->travlocks.off) { + /* No previous element: do normal find, and lock record */ + tdb->travlocks.off = tdb_find_lock(tdb, oldkey, F_WRLCK, &rec); + if (!tdb->travlocks.off) + return tdb_null; + tdb->travlocks.hash = BUCKET(rec.full_hash); + lock_record(tdb, tdb->travlocks.off); + } + oldhash = tdb->travlocks.hash; + + /* Grab next record: locks chain and returned record, + unlocks old record */ + if (tdb_next_lock(tdb, &tdb->travlocks, &rec) > 0) { + key.dsize = rec.key_len; + key.dptr = tdb_alloc_read(tdb, tdb->travlocks.off+sizeof(rec), + key.dsize); + /* Unlock the chain of this new record */ + tdb_unlock(tdb, tdb->travlocks.hash, F_WRLCK); + } + /* Unlock the chain of old record */ + tdb_unlock(tdb, BUCKET(oldhash), F_WRLCK); + return key; +} + +/* delete an entry in the database given a key */ +int tdb_delete(TDB_CONTEXT *tdb, TDB_DATA key) +{ + tdb_off rec_ptr; + struct list_struct rec; + int ret; + + if (!(rec_ptr = tdb_find_lock(tdb, key, F_WRLCK, &rec))) + return -1; + ret = do_delete(tdb, rec_ptr, &rec); + tdb_unlock(tdb, BUCKET(rec.full_hash), F_WRLCK); + return ret; +} + +/* store an element in the database, replacing any existing element + with the same key + + return 0 on success, -1 on failure +*/ +int tdb_store(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA dbuf, int flag) +{ + struct list_struct rec; + u32 hash; + tdb_off rec_ptr; + char *p = NULL; + int ret = 0; + + /* find which hash bucket it is in */ + hash = tdb_hash(&key); + if (!tdb_keylocked(tdb, hash)) + return -1; + if (tdb_lock(tdb, BUCKET(hash), F_WRLCK) == -1) + return -1; + + /* check for it existing, on insert. */ + if (flag == TDB_INSERT) { + if (tdb_exists(tdb, key)) { + tdb->ecode = TDB_ERR_EXISTS; + goto fail; + } + } else { + /* first try in-place update, on modify or replace. */ + if (tdb_update(tdb, key, dbuf) == 0) + goto out; + if (flag == TDB_MODIFY && tdb->ecode == TDB_ERR_NOEXIST) + goto fail; + } + /* reset the error code potentially set by the tdb_update() */ + tdb->ecode = TDB_SUCCESS; + + /* delete any existing record - if it doesn't exist we don't + care. Doing this first reduces fragmentation, and avoids + coalescing with `allocated' block before it's updated. */ + if (flag != TDB_INSERT) + tdb_delete(tdb, key); + + /* Copy key+value *before* allocating free space in case malloc + fails and we are left with a dead spot in the tdb. */ + + if (!(p = (char *)malloc(key.dsize + dbuf.dsize))) { + tdb->ecode = TDB_ERR_OOM; + goto fail; + } + + memcpy(p, key.dptr, key.dsize); + memcpy(p+key.dsize, dbuf.dptr, dbuf.dsize); + + /* now we're into insert / modify / replace of a record which + * we know could not be optimised by an in-place store (for + * various reasons). */ + if (!(rec_ptr = tdb_allocate(tdb, key.dsize + dbuf.dsize, &rec))) + goto fail; + + /* Read hash top into next ptr */ + if (ofs_read(tdb, TDB_HASH_TOP(hash), &rec.next) == -1) + goto fail; + + rec.key_len = key.dsize; + rec.data_len = dbuf.dsize; + rec.full_hash = hash; + rec.magic = TDB_MAGIC; + + /* write out and point the top of the hash chain at it */ + if (rec_write(tdb, rec_ptr, &rec) == -1 + || tdb_write(tdb, rec_ptr+sizeof(rec), p, key.dsize+dbuf.dsize)==-1 + || ofs_write(tdb, TDB_HASH_TOP(hash), &rec_ptr) == -1) { + fail: + /* Need to tdb_unallocate() here */ + ret = -1; + } + out: + if (p) + free(p); + tdb_unlock(tdb, BUCKET(hash), F_WRLCK); + return ret; +} + +static int tdb_already_open(dev_t device, + ino_t ino) +{ + TDB_CONTEXT *i; + + for (i = tdbs; i; i = i->next) { + if (i->device == device && i->inode == ino) { + return 1; + } + } + + return 0; +} + +/* open the database, creating it if necessary + + The open_flags and mode are passed straight to the open call on the + database file. A flags value of O_WRONLY is invalid. The hash size + is advisory, use zero for a default value. + + Return is NULL on error, in which case errno is also set. Don't + try to call tdb_error or tdb_errname, just do strerror(errno). + + @param name may be NULL for internal databases. */ +TDB_CONTEXT *tdb_open(const char *name, int hash_size, int tdb_flags, + int open_flags, mode_t mode) +{ + return tdb_open_ex(name, hash_size, tdb_flags, open_flags, mode, NULL); +} + + +TDB_CONTEXT *tdb_open_ex(const char *name, int hash_size, int tdb_flags, + int open_flags, mode_t mode, + tdb_log_func log_fn) +{ + TDB_CONTEXT *tdb; + struct stat st; + int rev = 0, locked; + + if (!(tdb = calloc(1, sizeof *tdb))) { + /* Can't log this */ + errno = ENOMEM; + goto fail; + } + tdb->fd = -1; + tdb->name = NULL; + tdb->map_ptr = NULL; + tdb->lockedkeys = NULL; + tdb->flags = tdb_flags; + tdb->open_flags = open_flags; + tdb->log_fn = log_fn; + + if ((open_flags & O_ACCMODE) == O_WRONLY) { + TDB_LOG((tdb, 0, "tdb_open_ex: can't open tdb %s write-only\n", + name)); + errno = EINVAL; + goto fail; + } + + if (hash_size == 0) + hash_size = DEFAULT_HASH_SIZE; + if ((open_flags & O_ACCMODE) == O_RDONLY) { + tdb->read_only = 1; + /* read only databases don't do locking or clear if first */ + tdb->flags |= TDB_NOLOCK; + tdb->flags &= ~TDB_CLEAR_IF_FIRST; + } + + /* internal databases don't mmap or lock, and start off cleared */ + if (tdb->flags & TDB_INTERNAL) { + tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP); + tdb->flags &= ~TDB_CLEAR_IF_FIRST; + tdb_new_database(tdb, hash_size); + goto internal; + } + + if ((tdb->fd = open(name, open_flags, mode)) == -1) { + TDB_LOG((tdb, 0, "tdb_open_ex: could not open file %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by open(2) */ + } + + /* ensure there is only one process initialising at once */ + if (tdb_brlock(tdb, GLOBAL_LOCK, F_WRLCK, F_SETLKW, 0) == -1) { + TDB_LOG((tdb, 0, "tdb_open_ex: failed to get global lock on %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by tdb_brlock */ + } + + /* we need to zero database if we are the only one with it open */ + if ((locked = (tdb_brlock(tdb, ACTIVE_LOCK, F_WRLCK, F_SETLK, 0) == 0)) + && (tdb_flags & TDB_CLEAR_IF_FIRST)) { + open_flags |= O_CREAT; + if (ftruncate(tdb->fd, 0) == -1) { + TDB_LOG((tdb, 0, "tdb_open_ex: " + "failed to truncate %s: %s\n", + name, strerror(errno))); + goto fail; /* errno set by ftruncate */ + } + } + + if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header) + || strcmp(tdb->header.magic_food, TDB_MAGIC_FOOD) != 0 + || (tdb->header.version != TDB_VERSION + && !(rev = (tdb->header.version==TDB_BYTEREV(TDB_VERSION))))) { + /* its not a valid database - possibly initialise it */ + if (!(open_flags & O_CREAT) || tdb_new_database(tdb, hash_size) == -1) { + errno = EIO; /* ie bad format or something */ + goto fail; + } + rev = (tdb->flags & TDB_CONVERT); + } + if (!rev) + tdb->flags &= ~TDB_CONVERT; + else { + tdb->flags |= TDB_CONVERT; + convert(&tdb->header, sizeof(tdb->header)); + } + if (fstat(tdb->fd, &st) == -1) + goto fail; + + /* Is it already in the open list? If so, fail. */ + if (tdb_already_open(st.st_dev, st.st_ino)) { + TDB_LOG((tdb, 2, "tdb_open_ex: " + "%s (%d,%d) is already open in this process\n", + name, st.st_dev, st.st_ino)); + errno = EBUSY; + goto fail; + } + + if (!(tdb->name = (char *)strdup(name))) { + errno = ENOMEM; + goto fail; + } + + tdb->map_size = st.st_size; + tdb->device = st.st_dev; + tdb->inode = st.st_ino; + tdb->locked = calloc(tdb->header.hash_size+1, sizeof(tdb->locked[0])); + if (!tdb->locked) { + TDB_LOG((tdb, 2, "tdb_open_ex: " + "failed to allocate lock structure for %s\n", + name)); + errno = ENOMEM; + goto fail; + } + tdb_mmap(tdb); + if (locked) { + if (!tdb->read_only) + tdb_clear_spinlocks(tdb); + if (tdb_brlock(tdb, ACTIVE_LOCK, F_UNLCK, F_SETLK, 0) == -1) { + TDB_LOG((tdb, 0, "tdb_open_ex: " + "failed to take ACTIVE_LOCK on %s: %s\n", + name, strerror(errno))); + goto fail; + } + } + /* leave this lock in place to indicate it's in use */ + if (tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0) == -1) + goto fail; + + internal: + /* Internal (memory-only) databases skip all the code above to + * do with disk files, and resume here by releasing their + * global lock and hooking into the active list. */ + if (tdb_brlock(tdb, GLOBAL_LOCK, F_UNLCK, F_SETLKW, 0) == -1) + goto fail; + tdb->next = tdbs; + tdbs = tdb; + return tdb; + + fail: + { int save_errno = errno; + + if (!tdb) + return NULL; + + if (tdb->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + free(tdb->map_ptr); + else + tdb_munmap(tdb); + } + if (tdb->name) + free(tdb->name); + if (tdb->fd != -1) + close(tdb->fd); + if (tdb->locked) + free(tdb->locked); + errno = save_errno; + return NULL; + } +} + +/* close a database */ +int tdb_close(TDB_CONTEXT *tdb) +{ + TDB_CONTEXT **i; + int ret = 0; + + if (tdb->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + free(tdb->map_ptr); + else + tdb_munmap(tdb); + } + if (tdb->name) + free(tdb->name); + if (tdb->fd != -1) + ret = close(tdb->fd); + if (tdb->locked) + free(tdb->locked); + if (tdb->lockedkeys) + free(tdb->lockedkeys); + + /* Remove from contexts list */ + for (i = &tdbs; *i; i = &(*i)->next) { + if (*i == tdb) { + *i = tdb->next; + break; + } + } + + memset(tdb, 0, sizeof(*tdb)); + free(tdb); + + return ret; +} + +/* lock/unlock entire database */ +int tdb_lockall(TDB_CONTEXT *tdb) +{ + u32 i; + + /* There are no locks on read-only dbs */ + if (tdb->read_only) + return TDB_ERRCODE(TDB_ERR_LOCK, -1); + if (tdb->lockedkeys) + return TDB_ERRCODE(TDB_ERR_NOLOCK, -1); + for (i = 0; i < tdb->header.hash_size; i++) + if (tdb_lock(tdb, i, F_WRLCK)) + break; + + /* If error, release locks we have... */ + if (i < tdb->header.hash_size) { + u32 j; + + for ( j = 0; j < i; j++) + tdb_unlock(tdb, j, F_WRLCK); + return TDB_ERRCODE(TDB_ERR_NOLOCK, -1); + } + + return 0; +} +void tdb_unlockall(TDB_CONTEXT *tdb) +{ + u32 i; + for (i=0; i < tdb->header.hash_size; i++) + tdb_unlock(tdb, i, F_WRLCK); +} + +int tdb_lockkeys(TDB_CONTEXT *tdb, u32 number, TDB_DATA keys[]) +{ + u32 i, j, hash; + + /* Can't lock more keys if already locked */ + if (tdb->lockedkeys) + return TDB_ERRCODE(TDB_ERR_NOLOCK, -1); + if (!(tdb->lockedkeys = malloc(sizeof(u32) * (number+1)))) + return TDB_ERRCODE(TDB_ERR_OOM, -1); + /* First number in array is # keys */ + tdb->lockedkeys[0] = number; + + /* Insertion sort by bucket */ + for (i = 0; i < number; i++) { + hash = tdb_hash(&keys[i]); + for (j = 0; j < i && BUCKET(tdb->lockedkeys[j+1]) < BUCKET(hash); j++); + memmove(&tdb->lockedkeys[j+2], &tdb->lockedkeys[j+1], sizeof(u32) * (i-j)); + tdb->lockedkeys[j+1] = hash; + } + /* Finally, lock in order */ + for (i = 0; i < number; i++) + if (tdb_lock(tdb, i, F_WRLCK)) + break; + + /* If error, release locks we have... */ + if (i < number) { + for ( j = 0; j < i; j++) + tdb_unlock(tdb, j, F_WRLCK); + free(tdb->lockedkeys); + tdb->lockedkeys = NULL; + return TDB_ERRCODE(TDB_ERR_NOLOCK, -1); + } + return 0; +} + +/* Unlock the keys previously locked by tdb_lockkeys() */ +void tdb_unlockkeys(TDB_CONTEXT *tdb) +{ + u32 i; + for (i = 0; i < tdb->lockedkeys[0]; i++) + tdb_unlock(tdb, tdb->lockedkeys[i+1], F_WRLCK); + free(tdb->lockedkeys); + tdb->lockedkeys = NULL; +} + +/* lock/unlock one hash chain. This is meant to be used to reduce + contention - it cannot guarantee how many records will be locked */ +int tdb_chainlock(TDB_CONTEXT *tdb, TDB_DATA key) +{ + return tdb_lock(tdb, BUCKET(tdb_hash(&key)), F_WRLCK); +} +void tdb_chainunlock(TDB_CONTEXT *tdb, TDB_DATA key) +{ + tdb_unlock(tdb, BUCKET(tdb_hash(&key)), F_WRLCK); +} + + +/* register a loging function */ +void tdb_logging_function(TDB_CONTEXT *tdb, void (*fn)(TDB_CONTEXT *, int , const char *, ...)) +{ + tdb->log_fn = fn; +} + + +/* reopen a tdb - this is used after a fork to ensure that we have an independent + seek pointer from our parent and to re-establish locks */ +int tdb_reopen(TDB_CONTEXT *tdb) +{ + struct stat st; + + tdb_munmap(tdb); + close(tdb->fd); + tdb->fd = open(tdb->name, tdb->open_flags & ~(O_CREAT|O_TRUNC), 0); + if (tdb->fd == -1) { + TDB_LOG((tdb, 0, "tdb_reopen: open failed (%s)\n", strerror(errno))); + goto fail; + } + fstat(tdb->fd, &st); + if (st.st_ino != tdb->inode || st.st_dev != tdb->device) { + TDB_LOG((tdb, 0, "tdb_reopen: file dev/inode has changed!\n")); + goto fail; + } + tdb_mmap(tdb); + if (tdb_brlock(tdb, ACTIVE_LOCK, F_RDLCK, F_SETLKW, 0) == -1) { + TDB_LOG((tdb, 0, "tdb_reopen: failed to obtain active lock\n")); + goto fail; + } + + return 0; + +fail: + tdb_close(tdb); + return -1; +} + +/* reopen all tdb's */ +int tdb_reopen_all(void) +{ + TDB_CONTEXT *tdb; + + for (tdb=tdbs; tdb; tdb = tdb->next) { + if (tdb_reopen(tdb) != 0) return -1; + } + + return 0; +} |