diff options
Diffstat (limited to 'lib/tdb2/open.c')
| -rw-r--r-- | lib/tdb2/open.c | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/lib/tdb2/open.c b/lib/tdb2/open.c new file mode 100644 index 00000000000..c35598cdcce --- /dev/null +++ b/lib/tdb2/open.c @@ -0,0 +1,661 @@ +#include "private.h" +#include <ccan/hash/hash.h> +#include <assert.h> + +/* all lock info, to detect double-opens (fcntl file don't nest!) */ +static struct tdb_file *files = NULL; + +static struct tdb_file *find_file(dev_t device, ino_t ino) +{ + struct tdb_file *i; + + for (i = files; i; i = i->next) { + if (i->device == device && i->inode == ino) { + i->refcnt++; + break; + } + } + return i; +} + +static bool read_all(int fd, void *buf, size_t len) +{ + while (len) { + ssize_t ret; + ret = read(fd, buf, len); + if (ret < 0) + return false; + if (ret == 0) { + /* ETOOSHORT? */ + errno = EWOULDBLOCK; + return false; + } + buf = (char *)buf + ret; + len -= ret; + } + return true; +} + +static uint64_t random_number(struct tdb_context *tdb) +{ + int fd; + uint64_t ret = 0; + struct timeval now; + + fd = open("/dev/urandom", O_RDONLY); + if (fd >= 0) { + if (read_all(fd, &ret, sizeof(ret))) { + close(fd); + return ret; + } + close(fd); + } + /* FIXME: Untested! Based on Wikipedia protocol description! */ + fd = open("/dev/egd-pool", O_RDWR); + if (fd >= 0) { + /* Command is 1, next byte is size we want to read. */ + char cmd[2] = { 1, sizeof(uint64_t) }; + if (write(fd, cmd, sizeof(cmd)) == sizeof(cmd)) { + char reply[1 + sizeof(uint64_t)]; + int r = read(fd, reply, sizeof(reply)); + if (r > 1) { + /* Copy at least some bytes. */ + memcpy(&ret, reply+1, r - 1); + if (reply[0] == sizeof(uint64_t) + && r == sizeof(reply)) { + close(fd); + return ret; + } + } + } + close(fd); + } + + /* Fallback: pid and time. */ + gettimeofday(&now, NULL); + ret = getpid() * 100132289ULL + now.tv_sec * 1000000ULL + now.tv_usec; + tdb_logerr(tdb, TDB_SUCCESS, TDB_LOG_WARNING, + "tdb_open: random from getpid and time"); + return ret; +} + +struct new_database { + struct tdb_header hdr; + struct tdb_freetable ftable; +}; + +/* initialise a new database */ +static enum TDB_ERROR tdb_new_database(struct tdb_context *tdb, + struct tdb_attribute_seed *seed, + struct tdb_header *hdr) +{ + /* We make it up in memory, then write it out if not internal */ + struct new_database newdb; + unsigned int magic_len; + ssize_t rlen; + enum TDB_ERROR ecode; + + /* Fill in the header */ + newdb.hdr.version = TDB_VERSION; + if (seed) + newdb.hdr.hash_seed = seed->seed; + else + newdb.hdr.hash_seed = random_number(tdb); + newdb.hdr.hash_test = TDB_HASH_MAGIC; + newdb.hdr.hash_test = tdb->hash_fn(&newdb.hdr.hash_test, + sizeof(newdb.hdr.hash_test), + newdb.hdr.hash_seed, + tdb->hash_data); + newdb.hdr.recovery = 0; + newdb.hdr.features_used = newdb.hdr.features_offered = TDB_FEATURE_MASK; + newdb.hdr.seqnum = 0; + memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved)); + /* Initial hashes are empty. */ + memset(newdb.hdr.hashtable, 0, sizeof(newdb.hdr.hashtable)); + + /* Free is empty. */ + newdb.hdr.free_table = offsetof(struct new_database, ftable); + memset(&newdb.ftable, 0, sizeof(newdb.ftable)); + ecode = set_header(NULL, &newdb.ftable.hdr, TDB_FTABLE_MAGIC, 0, + sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr), + sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr), + 0); + if (ecode != TDB_SUCCESS) { + return ecode; + } + + /* Magic food */ + memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food)); + strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD); + + /* This creates an endian-converted database, as if read from disk */ + magic_len = sizeof(newdb.hdr.magic_food); + tdb_convert(tdb, + (char *)&newdb.hdr + magic_len, sizeof(newdb) - magic_len); + + *hdr = newdb.hdr; + + if (tdb->flags & TDB_INTERNAL) { + tdb->file->map_size = sizeof(newdb); + tdb->file->map_ptr = malloc(tdb->file->map_size); + if (!tdb->file->map_ptr) { + return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR, + "tdb_new_database:" + " failed to allocate"); + } + memcpy(tdb->file->map_ptr, &newdb, tdb->file->map_size); + return TDB_SUCCESS; + } + if (lseek(tdb->file->fd, 0, SEEK_SET) == -1) { + return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_new_database:" + " failed to seek: %s", strerror(errno)); + } + + if (ftruncate(tdb->file->fd, 0) == -1) { + return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_new_database:" + " failed to truncate: %s", strerror(errno)); + } + + rlen = write(tdb->file->fd, &newdb, sizeof(newdb)); + if (rlen != sizeof(newdb)) { + if (rlen >= 0) + errno = ENOSPC; + return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_new_database: %zi writing header: %s", + rlen, strerror(errno)); + } + return TDB_SUCCESS; +} + +static enum TDB_ERROR tdb_new_file(struct tdb_context *tdb) +{ + tdb->file = malloc(sizeof(*tdb->file)); + if (!tdb->file) + return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR, + "tdb_open: cannot alloc tdb_file structure"); + tdb->file->num_lockrecs = 0; + tdb->file->lockrecs = NULL; + tdb->file->allrecord_lock.count = 0; + tdb->file->refcnt = 1; + return TDB_SUCCESS; +} + +enum TDB_ERROR tdb_set_attribute(struct tdb_context *tdb, + const union tdb_attribute *attr) +{ + switch (attr->base.attr) { + case TDB_ATTRIBUTE_LOG: + tdb->log_fn = attr->log.fn; + tdb->log_data = attr->log.data; + break; + case TDB_ATTRIBUTE_HASH: + case TDB_ATTRIBUTE_SEED: + case TDB_ATTRIBUTE_OPENHOOK: + return tdb->last_error + = tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_set_attribute:" + " cannot set %s after opening", + attr->base.attr == TDB_ATTRIBUTE_HASH + ? "TDB_ATTRIBUTE_HASH" + : attr->base.attr == TDB_ATTRIBUTE_SEED + ? "TDB_ATTRIBUTE_SEED" + : "TDB_ATTRIBUTE_OPENHOOK"); + case TDB_ATTRIBUTE_STATS: + return tdb->last_error + = tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_set_attribute:" + " cannot set TDB_ATTRIBUTE_STATS"); + case TDB_ATTRIBUTE_FLOCK: + tdb->lock_fn = attr->flock.lock; + tdb->unlock_fn = attr->flock.unlock; + tdb->lock_data = attr->flock.data; + break; + default: + return tdb->last_error + = tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_set_attribute:" + " unknown attribute type %u", + attr->base.attr); + } + return TDB_SUCCESS; +} + +static uint64_t jenkins_hash(const void *key, size_t length, uint64_t seed, + void *unused) +{ + uint64_t ret; + /* hash64_stable assumes lower bits are more important; they are a + * slightly better hash. We use the upper bits first, so swap them. */ + ret = hash64_stable((const unsigned char *)key, length, seed); + return (ret >> 32) | (ret << 32); +} + +enum TDB_ERROR tdb_get_attribute(struct tdb_context *tdb, + union tdb_attribute *attr) +{ + switch (attr->base.attr) { + case TDB_ATTRIBUTE_LOG: + if (!tdb->log_fn) + return tdb->last_error = TDB_ERR_NOEXIST; + attr->log.fn = tdb->log_fn; + attr->log.data = tdb->log_data; + break; + case TDB_ATTRIBUTE_HASH: + attr->hash.fn = tdb->hash_fn; + attr->hash.data = tdb->hash_data; + break; + case TDB_ATTRIBUTE_SEED: + attr->seed.seed = tdb->hash_seed; + break; + case TDB_ATTRIBUTE_OPENHOOK: + return tdb->last_error + = tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_get_attribute:" + " cannot get TDB_ATTRIBUTE_OPENHOOK"); + case TDB_ATTRIBUTE_STATS: { + size_t size = attr->stats.size; + if (size > tdb->stats.size) + size = tdb->stats.size; + memcpy(&attr->stats, &tdb->stats, size); + break; + } + case TDB_ATTRIBUTE_FLOCK: + attr->flock.lock = tdb->lock_fn; + attr->flock.unlock = tdb->unlock_fn; + attr->flock.data = tdb->lock_data; + break; + default: + return tdb->last_error + = tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_get_attribute:" + " unknown attribute type %u", + attr->base.attr); + } + attr->base.next = NULL; + return TDB_SUCCESS; +} + +void tdb_unset_attribute(struct tdb_context *tdb, + enum tdb_attribute_type type) +{ + switch (type) { + case TDB_ATTRIBUTE_LOG: + tdb->log_fn = NULL; + break; + case TDB_ATTRIBUTE_HASH: + case TDB_ATTRIBUTE_SEED: + case TDB_ATTRIBUTE_OPENHOOK: + tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR, + "tdb_unset_attribute: cannot unset %s after opening", + type == TDB_ATTRIBUTE_HASH + ? "TDB_ATTRIBUTE_HASH" + : type == TDB_ATTRIBUTE_SEED + ? "TDB_ATTRIBUTE_SEED" + : "TDB_ATTRIBUTE_OPENHOOK"); + break; + case TDB_ATTRIBUTE_STATS: + tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_unset_attribute:" + "cannot unset TDB_ATTRIBUTE_STATS"); + break; + case TDB_ATTRIBUTE_FLOCK: + tdb->lock_fn = tdb_fcntl_lock; + tdb->unlock_fn = tdb_fcntl_unlock; + break; + default: + tdb_logerr(tdb, TDB_ERR_EINVAL, + TDB_LOG_USE_ERROR, + "tdb_unset_attribute: unknown attribute type %u", + type); + } +} + +struct tdb_context *tdb_open(const char *name, int tdb_flags, + int open_flags, mode_t mode, + union tdb_attribute *attr) +{ + struct tdb_context *tdb; + struct stat st; + int saved_errno = 0; + uint64_t hash_test; + unsigned v; + ssize_t rlen; + struct tdb_header hdr; + struct tdb_attribute_seed *seed = NULL; + struct tdb_attribute_openhook *openhook = NULL; + tdb_bool_err berr; + enum TDB_ERROR ecode; + int openlock; + + tdb = malloc(sizeof(*tdb) + (name ? strlen(name) + 1 : 0)); + if (!tdb) { + /* Can't log this */ + errno = ENOMEM; + return NULL; + } + /* Set name immediately for logging functions. */ + if (name) { + tdb->name = strcpy((char *)(tdb + 1), name); + } else { + tdb->name = NULL; + } + tdb->direct_access = 0; + tdb->flags = tdb_flags; + tdb->log_fn = NULL; + tdb->transaction = NULL; + tdb->access = NULL; + tdb->last_error = TDB_SUCCESS; + tdb->file = NULL; + tdb->lock_fn = tdb_fcntl_lock; + tdb->unlock_fn = tdb_fcntl_unlock; + tdb->hash_fn = jenkins_hash; + memset(&tdb->stats, 0, sizeof(tdb->stats)); + tdb->stats.base.attr = TDB_ATTRIBUTE_STATS; + tdb->stats.size = sizeof(tdb->stats); + tdb_io_init(tdb); + + while (attr) { + switch (attr->base.attr) { + case TDB_ATTRIBUTE_HASH: + tdb->hash_fn = attr->hash.fn; + tdb->hash_data = attr->hash.data; + break; + case TDB_ATTRIBUTE_SEED: + seed = &attr->seed; + break; + case TDB_ATTRIBUTE_OPENHOOK: + openhook = &attr->openhook; + break; + default: + /* These are set as normal. */ + ecode = tdb_set_attribute(tdb, attr); + if (ecode != TDB_SUCCESS) + goto fail; + } + attr = attr->base.next; + } + + if (tdb_flags & ~(TDB_INTERNAL | TDB_NOLOCK | TDB_NOMMAP | TDB_CONVERT + | TDB_NOSYNC | TDB_SEQNUM | TDB_ALLOW_NESTING)) { + ecode = tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR, + "tdb_open: unknown flags %u", tdb_flags); + goto fail; + } + + if ((open_flags & O_ACCMODE) == O_WRONLY) { + ecode = tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR, + "tdb_open: can't open tdb %s write-only", + name); + goto fail; + } + + if ((open_flags & O_ACCMODE) == O_RDONLY) { + tdb->read_only = true; + tdb->mmap_flags = PROT_READ; + openlock = F_RDLCK; + } else { + tdb->read_only = false; + tdb->mmap_flags = PROT_READ | PROT_WRITE; + openlock = F_WRLCK; + } + + /* internal databases don't need any of the rest. */ + if (tdb->flags & TDB_INTERNAL) { + tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP); + ecode = tdb_new_file(tdb); + if (ecode != TDB_SUCCESS) { + goto fail; + } + tdb->file->fd = -1; + ecode = tdb_new_database(tdb, seed, &hdr); + if (ecode != TDB_SUCCESS) { + goto fail; + } + tdb_convert(tdb, &hdr.hash_seed, sizeof(hdr.hash_seed)); + tdb->hash_seed = hdr.hash_seed; + tdb_ftable_init(tdb); + return tdb; + } + + if (stat(name, &st) != -1) + tdb->file = find_file(st.st_dev, st.st_ino); + + if (!tdb->file) { + int fd; + + if ((fd = open(name, open_flags, mode)) == -1) { + /* errno set by open(2) */ + saved_errno = errno; + tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open: could not open file %s: %s", + name, strerror(errno)); + goto fail_errno; + } + + /* on exec, don't inherit the fd */ + v = fcntl(fd, F_GETFD, 0); + fcntl(fd, F_SETFD, v | FD_CLOEXEC); + + if (fstat(fd, &st) == -1) { + saved_errno = errno; + tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open: could not stat open %s: %s", + name, strerror(errno)); + close(fd); + goto fail_errno; + } + + ecode = tdb_new_file(tdb); + if (ecode != TDB_SUCCESS) { + close(fd); + goto fail; + } + + tdb->file->next = files; + tdb->file->fd = fd; + tdb->file->device = st.st_dev; + tdb->file->inode = st.st_ino; + tdb->file->map_ptr = NULL; + tdb->file->map_size = sizeof(struct tdb_header); + } + + /* ensure there is only one process initialising at once */ + ecode = tdb_lock_open(tdb, openlock, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK); + if (ecode != TDB_SUCCESS) { + saved_errno = errno; + goto fail_errno; + } + + /* call their open hook if they gave us one. */ + if (openhook) { + ecode = openhook->fn(tdb->file->fd, openhook->data); + if (ecode != TDB_SUCCESS) { + tdb_logerr(tdb, ecode, TDB_LOG_ERROR, + "tdb_open: open hook failed"); + goto fail; + } + open_flags |= O_CREAT; + } + + /* If they used O_TRUNC, read will return 0. */ + rlen = pread(tdb->file->fd, &hdr, sizeof(hdr), 0); + if (rlen == 0 && (open_flags & O_CREAT)) { + ecode = tdb_new_database(tdb, seed, &hdr); + if (ecode != TDB_SUCCESS) { + goto fail; + } + } else if (rlen < 0) { + ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open: error %s reading %s", + strerror(errno), name); + goto fail; + } else if (rlen < sizeof(hdr) + || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) { + ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open: %s is not a tdb file", name); + goto fail; + } + + if (hdr.version != TDB_VERSION) { + if (hdr.version == bswap_64(TDB_VERSION)) + tdb->flags |= TDB_CONVERT; + else { + /* wrong version */ + ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open:" + " %s is unknown version 0x%llx", + name, (long long)hdr.version); + goto fail; + } + } + + tdb_convert(tdb, &hdr, sizeof(hdr)); + tdb->hash_seed = hdr.hash_seed; + hash_test = TDB_HASH_MAGIC; + hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test)); + if (hdr.hash_test != hash_test) { + /* wrong hash variant */ + ecode = tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open:" + " %s uses a different hash function", + name); + goto fail; + } + + /* Clear any features we don't understand. */ + if ((open_flags & O_ACCMODE) != O_RDONLY) { + hdr.features_used &= TDB_FEATURE_MASK; + if (tdb_write_convert(tdb, offsetof(struct tdb_header, + features_used), + &hdr.features_used, + sizeof(hdr.features_used)) == -1) + goto fail; + } + + tdb_unlock_open(tdb, openlock); + + /* This make sure we have current map_size and mmap. */ + tdb->methods->oob(tdb, tdb->file->map_size + 1, true); + + /* Now it's fully formed, recover if necessary. */ + berr = tdb_needs_recovery(tdb); + if (unlikely(berr != false)) { + if (berr < 0) { + ecode = berr; + goto fail; + } + ecode = tdb_lock_and_recover(tdb); + if (ecode != TDB_SUCCESS) { + goto fail; + } + } + + ecode = tdb_ftable_init(tdb); + if (ecode != TDB_SUCCESS) { + goto fail; + } + + /* Add to linked list if we're new. */ + if (tdb->file->refcnt == 1) + files = tdb->file; + return tdb; + + fail: + /* Map ecode to some logical errno. */ + switch (ecode) { + case TDB_ERR_CORRUPT: + case TDB_ERR_IO: + saved_errno = EIO; + break; + case TDB_ERR_LOCK: + saved_errno = EWOULDBLOCK; + break; + case TDB_ERR_OOM: + saved_errno = ENOMEM; + break; + case TDB_ERR_EINVAL: + saved_errno = EINVAL; + break; + default: + saved_errno = EINVAL; + break; + } + +fail_errno: +#ifdef TDB_TRACE + close(tdb->tracefd); +#endif + if (tdb->file) { + tdb_lock_cleanup(tdb); + if (--tdb->file->refcnt == 0) { + assert(tdb->file->num_lockrecs == 0); + if (tdb->file->map_ptr) { + if (tdb->flags & TDB_INTERNAL) { + free(tdb->file->map_ptr); + } else + tdb_munmap(tdb->file); + } + if (close(tdb->file->fd) != 0) + tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR, + "tdb_open: failed to close tdb fd" + " on error: %s", strerror(errno)); + free(tdb->file->lockrecs); + free(tdb->file); + } + } + + free(tdb); + errno = saved_errno; + return NULL; +} + +int tdb_close(struct tdb_context *tdb) +{ + int ret = 0; + + tdb_trace(tdb, "tdb_close"); + + if (tdb->transaction) { + tdb_transaction_cancel(tdb); + } + + if (tdb->file->map_ptr) { + if (tdb->flags & TDB_INTERNAL) + free(tdb->file->map_ptr); + else + tdb_munmap(tdb->file); + } + if (tdb->file) { + struct tdb_file **i; + + tdb_lock_cleanup(tdb); + if (--tdb->file->refcnt == 0) { + ret = close(tdb->file->fd); + + /* Remove from files list */ + for (i = &files; *i; i = &(*i)->next) { + if (*i == tdb->file) { + *i = tdb->file->next; + break; + } + } + free(tdb->file->lockrecs); + free(tdb->file); + } + } + +#ifdef TDB_TRACE + close(tdb->tracefd); +#endif + free(tdb); + + return ret; +} |