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|
/*
Unix SMB/CIFS implementation.
trivial database library
Copyright (C) Andrew Tridgell 1999-2005
Copyright (C) Paul `Rusty' Russell 2000
Copyright (C) Jeremy Allison 2000-2003
** 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 "tdb1_private.h"
/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
static struct tdb1_context *tdb1s = NULL;
/* We use two hashes to double-check they're using the right hash function. */
void tdb1_header_hash(struct tdb1_context *tdb,
uint32_t *magic1_hash, uint32_t *magic2_hash)
{
TDB1_DATA hash_key;
uint32_t tdb1_magic = TDB1_MAGIC;
hash_key.dptr = (unsigned char *)TDB1_MAGIC_FOOD;
hash_key.dsize = sizeof(TDB1_MAGIC_FOOD);
*magic1_hash = tdb->hash_fn(&hash_key);
hash_key.dptr = (unsigned char *)TDB1_CONV(tdb1_magic);
hash_key.dsize = sizeof(tdb1_magic);
*magic2_hash = tdb->hash_fn(&hash_key);
/* Make sure at least one hash is non-zero! */
if (*magic1_hash == 0 && *magic2_hash == 0)
*magic1_hash = 1;
}
/* initialise a new database with a specified hash size */
static int tdb1_new_database(struct tdb1_context *tdb, int hash_size)
{
struct tdb1_header *newdb;
size_t size;
int ret = -1;
/* We make it up in memory, then write it out if not internal */
size = sizeof(struct tdb1_header) + (hash_size+1)*sizeof(tdb1_off_t);
if (!(newdb = (struct tdb1_header *)calloc(size, 1))) {
tdb->ecode = TDB1_ERR_OOM;
return -1;
}
/* Fill in the header */
newdb->version = TDB1_VERSION;
newdb->hash_size = hash_size;
tdb1_header_hash(tdb, &newdb->magic1_hash, &newdb->magic2_hash);
/* Make sure older tdbs (which don't check the magic hash fields)
* will refuse to open this TDB. */
if (tdb->flags & TDB1_INCOMPATIBLE_HASH)
newdb->rwlocks = TDB1_HASH_RWLOCK_MAGIC;
if (tdb->flags & TDB1_INTERNAL) {
tdb->map_size = size;
tdb->map_ptr = (char *)newdb;
memcpy(&tdb->header, newdb, sizeof(tdb->header));
/* Convert the `ondisk' version if asked. */
TDB1_CONV(*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 */
TDB1_CONV(*newdb);
memcpy(&tdb->header, newdb, sizeof(tdb->header));
/* Don't endian-convert the magic food! */
memcpy(newdb->magic_food, TDB1_MAGIC_FOOD, strlen(TDB1_MAGIC_FOOD)+1);
/* we still have "ret == -1" here */
if (tdb1_write_all(tdb->fd, newdb, size))
ret = 0;
fail:
SAFE_FREE(newdb);
return ret;
}
static int tdb1_already_open(dev_t device,
ino_t ino)
{
struct tdb1_context *i;
for (i = tdb1s; 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 tdb1_error or tdb1_errname, just do strerror(errno).
@param name may be NULL for internal databases. */
struct tdb1_context *tdb1_open(const char *name, int hash_size, int tdb1_flags,
int open_flags, mode_t mode)
{
return tdb1_open_ex(name, hash_size, tdb1_flags, open_flags, mode, NULL, NULL);
}
/* a default logging function */
static void null_log_fn(struct tdb1_context *tdb, enum tdb1_debug_level level, const char *fmt, ...) PRINTF_ATTRIBUTE(3, 4);
static void null_log_fn(struct tdb1_context *tdb, enum tdb1_debug_level level, const char *fmt, ...)
{
}
static bool check_header_hash(struct tdb1_context *tdb,
bool default_hash, uint32_t *m1, uint32_t *m2)
{
tdb1_header_hash(tdb, m1, m2);
if (tdb->header.magic1_hash == *m1 &&
tdb->header.magic2_hash == *m2) {
return true;
}
/* If they explicitly set a hash, always respect it. */
if (!default_hash)
return false;
/* Otherwise, try the other inbuilt hash. */
if (tdb->hash_fn == tdb1_old_hash)
tdb->hash_fn = tdb1_jenkins_hash;
else
tdb->hash_fn = tdb1_old_hash;
return check_header_hash(tdb, false, m1, m2);
}
struct tdb1_context *tdb1_open_ex(const char *name, int hash_size, int tdb1_flags,
int open_flags, mode_t mode,
const struct tdb1_logging_context *log_ctx,
tdb1_hash_func hash_fn)
{
struct tdb1_context *tdb;
struct stat st;
int rev = 0, locked = 0;
unsigned char *vp;
uint32_t vertest;
unsigned v;
const char *hash_alg;
uint32_t magic1, magic2;
if (!(tdb = (struct tdb1_context *)calloc(1, sizeof *tdb))) {
/* Can't log this */
errno = ENOMEM;
goto fail;
}
tdb1_io_init(tdb);
tdb->fd = -1;
tdb->name = NULL;
tdb->map_ptr = NULL;
tdb->flags = tdb1_flags;
tdb->open_flags = open_flags;
if (log_ctx) {
tdb->log = *log_ctx;
} else {
tdb->log.log_fn = null_log_fn;
tdb->log.log_private = NULL;
}
if (name == NULL && (tdb1_flags & TDB1_INTERNAL)) {
name = "__TDB1_INTERNAL__";
}
if (name == NULL) {
tdb->name = (char *)"__NULL__";
TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: called with name == NULL\n"));
tdb->name = NULL;
errno = EINVAL;
goto fail;
}
/* now make a copy of the name, as the caller memory might went away */
if (!(tdb->name = (char *)strdup(name))) {
/*
* set the name as the given string, so that tdb1_name() will
* work in case of an error.
*/
tdb->name = (char *)name;
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: can't strdup(%s)\n",
name));
tdb->name = NULL;
errno = ENOMEM;
goto fail;
}
if (hash_fn) {
tdb->hash_fn = hash_fn;
hash_alg = "the user defined";
} else {
/* This controls what we use when creating a tdb. */
if (tdb->flags & TDB1_INCOMPATIBLE_HASH) {
tdb->hash_fn = tdb1_jenkins_hash;
} else {
tdb->hash_fn = tdb1_old_hash;
}
hash_alg = "either default";
}
/* cache the page size */
tdb->page_size = getpagesize();
if (tdb->page_size <= 0) {
tdb->page_size = 0x2000;
}
tdb->max_dead_records = (tdb1_flags & TDB1_VOLATILE) ? 5 : 0;
if ((open_flags & O_ACCMODE) == O_WRONLY) {
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: can't open tdb %s write-only\n",
name));
errno = EINVAL;
goto fail;
}
if (hash_size == 0)
hash_size = TDB1_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 |= TDB1_NOLOCK;
tdb->flags &= ~TDB1_CLEAR_IF_FIRST;
}
if ((tdb->flags & TDB1_ALLOW_NESTING) &&
(tdb->flags & TDB1_DISALLOW_NESTING)) {
tdb->ecode = TDB1_ERR_NESTING;
TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: "
"allow_nesting and disallow_nesting are not allowed together!"));
errno = EINVAL;
goto fail;
}
/*
* TDB1_ALLOW_NESTING is the default behavior.
* Note: this may change in future versions!
*/
if (!(tdb->flags & TDB1_DISALLOW_NESTING)) {
tdb->flags |= TDB1_ALLOW_NESTING;
}
/* internal databases don't mmap or lock, and start off cleared */
if (tdb->flags & TDB1_INTERNAL) {
tdb->flags |= (TDB1_NOLOCK | TDB1_NOMMAP);
tdb->flags &= ~TDB1_CLEAR_IF_FIRST;
if (tdb1_new_database(tdb, hash_size) != 0) {
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: tdb1_new_database failed!"));
goto fail;
}
goto internal;
}
if ((tdb->fd = open(name, open_flags, mode)) == -1) {
TDB1_LOG((tdb, TDB1_DEBUG_WARNING, "tdb1_open_ex: could not open file %s: %s\n",
name, strerror(errno)));
goto fail; /* errno set by open(2) */
}
/* on exec, don't inherit the fd */
v = fcntl(tdb->fd, F_GETFD, 0);
fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
/* ensure there is only one process initialising at once */
if (tdb1_nest_lock(tdb, TDB1_OPEN_LOCK, F_WRLCK, TDB1_LOCK_WAIT) == -1) {
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: failed to get open lock on %s: %s\n",
name, strerror(errno)));
goto fail; /* errno set by tdb1_brlock */
}
/* we need to zero database if we are the only one with it open */
if ((tdb1_flags & TDB1_CLEAR_IF_FIRST) &&
(!tdb->read_only) &&
(locked = (tdb1_nest_lock(tdb, TDB1_ACTIVE_LOCK, F_WRLCK, TDB1_LOCK_NOWAIT|TDB1_LOCK_PROBE) == 0))) {
open_flags |= O_CREAT;
if (ftruncate(tdb->fd, 0) == -1) {
TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: "
"failed to truncate %s: %s\n",
name, strerror(errno)));
goto fail; /* errno set by ftruncate */
}
}
errno = 0;
if (read(tdb->fd, &tdb->header, sizeof(tdb->header)) != sizeof(tdb->header)
|| strcmp(tdb->header.magic_food, TDB1_MAGIC_FOOD) != 0) {
if (!(open_flags & O_CREAT) || tdb1_new_database(tdb, hash_size) == -1) {
if (errno == 0) {
errno = EIO; /* ie bad format or something */
}
goto fail;
}
rev = (tdb->flags & TDB1_CONVERT);
} else if (tdb->header.version != TDB1_VERSION
&& !(rev = (tdb->header.version==TDB1_BYTEREV(TDB1_VERSION)))) {
/* wrong version */
errno = EIO;
goto fail;
}
vp = (unsigned char *)&tdb->header.version;
vertest = (((uint32_t)vp[0]) << 24) | (((uint32_t)vp[1]) << 16) |
(((uint32_t)vp[2]) << 8) | (uint32_t)vp[3];
tdb->flags |= (vertest==TDB1_VERSION) ? TDB1_BIGENDIAN : 0;
if (!rev)
tdb->flags &= ~TDB1_CONVERT;
else {
tdb->flags |= TDB1_CONVERT;
tdb1_convert(&tdb->header, sizeof(tdb->header));
}
if (fstat(tdb->fd, &st) == -1)
goto fail;
if (tdb->header.rwlocks != 0 &&
tdb->header.rwlocks != TDB1_HASH_RWLOCK_MAGIC) {
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: spinlocks no longer supported\n"));
goto fail;
}
if ((tdb->header.magic1_hash == 0) && (tdb->header.magic2_hash == 0)) {
/* older TDB without magic hash references */
tdb->hash_fn = tdb1_old_hash;
} else if (!check_header_hash(tdb, !hash_fn, &magic1, &magic2)) {
TDB1_LOG((tdb, TDB1_DEBUG_FATAL, "tdb1_open_ex: "
"%s was not created with %s hash function we are using\n"
"magic1_hash[0x%08X %s 0x%08X] "
"magic2_hash[0x%08X %s 0x%08X]\n",
name, hash_alg,
tdb->header.magic1_hash,
(tdb->header.magic1_hash == magic1) ? "==" : "!=",
magic1,
tdb->header.magic2_hash,
(tdb->header.magic2_hash == magic2) ? "==" : "!=",
magic2));
errno = EINVAL;
goto fail;
}
/* Is it already in the open list? If so, fail. */
if (tdb1_already_open(st.st_dev, st.st_ino)) {
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: "
"%s (%d,%d) is already open in this process\n",
name, (int)st.st_dev, (int)st.st_ino));
errno = EBUSY;
goto fail;
}
tdb->map_size = st.st_size;
tdb->device = st.st_dev;
tdb->inode = st.st_ino;
tdb1_mmap(tdb);
if (locked) {
if (tdb1_nest_unlock(tdb, TDB1_ACTIVE_LOCK, F_WRLCK) == -1) {
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: "
"failed to release ACTIVE_LOCK on %s: %s\n",
name, strerror(errno)));
goto fail;
}
}
/* We always need to do this if the CLEAR_IF_FIRST flag is set, even if
we didn't get the initial exclusive lock as we need to let all other
users know we're using it. */
if (tdb1_flags & TDB1_CLEAR_IF_FIRST) {
/* leave this lock in place to indicate it's in use */
if (tdb1_nest_lock(tdb, TDB1_ACTIVE_LOCK, F_RDLCK, TDB1_LOCK_WAIT) == -1) {
goto fail;
}
}
/* if needed, run recovery */
if (tdb1_transaction_recover(tdb) == -1) {
goto fail;
}
internal:
/* Internal (memory-only) databases skip all the code above to
* do with disk files, and resume here by releasing their
* open lock and hooking into the active list. */
if (tdb1_nest_unlock(tdb, TDB1_OPEN_LOCK, F_WRLCK) == -1) {
goto fail;
}
tdb->next = tdb1s;
tdb1s = tdb;
return tdb;
fail:
{ int save_errno = errno;
if (!tdb)
return NULL;
if (tdb->map_ptr) {
if (tdb->flags & TDB1_INTERNAL)
SAFE_FREE(tdb->map_ptr);
else
tdb1_munmap(tdb);
}
if (tdb->fd != -1)
if (close(tdb->fd) != 0)
TDB1_LOG((tdb, TDB1_DEBUG_ERROR, "tdb1_open_ex: failed to close tdb->fd on error!\n"));
SAFE_FREE(tdb->lockrecs);
SAFE_FREE(tdb->name);
SAFE_FREE(tdb);
errno = save_errno;
return NULL;
}
}
/*
* Set the maximum number of dead records per hash chain
*/
void tdb1_set_max_dead(struct tdb1_context *tdb, int max_dead)
{
tdb->max_dead_records = max_dead;
}
/**
* Close a database.
*
* @returns -1 for error; 0 for success.
**/
int tdb1_close(struct tdb1_context *tdb)
{
struct tdb1_context **i;
int ret = 0;
if (tdb->transaction) {
tdb1_transaction_cancel(tdb);
}
if (tdb->map_ptr) {
if (tdb->flags & TDB1_INTERNAL)
SAFE_FREE(tdb->map_ptr);
else
tdb1_munmap(tdb);
}
SAFE_FREE(tdb->name);
if (tdb->fd != -1) {
ret = close(tdb->fd);
tdb->fd = -1;
}
SAFE_FREE(tdb->lockrecs);
/* Remove from contexts list */
for (i = &tdb1s; *i; i = &(*i)->next) {
if (*i == tdb) {
*i = tdb->next;
break;
}
}
memset(tdb, 0, sizeof(*tdb));
SAFE_FREE(tdb);
return ret;
}
|