tdb2: make TDB1 code use tdb2's TDB_ERROR and tdb_logerr()

[Samba/gbeck.git] / lib / tdb2 / tdb1_open.c

 /*
   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->last_error = TDB_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);
}

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_fn = log_ctx->log_fn;
                tdb->log_data = log_ctx->log_private;
        } else
                tdb->log_fn = NULL;

        if (name == NULL && (tdb1_flags & TDB1_INTERNAL)) {
                name = "__TDB1_INTERNAL__";
        }

        if (name == NULL) {
                tdb->name = (char *)"__NULL__";
                tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
                           "tdb1_open_ex: called with name == NULL");
                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;
                tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
                           "tdb1_open_ex: can't strdup(%s)", 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) {
                tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
                           "tdb1_open_ex: can't open tdb %s write-only",
                           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_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
                           "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) {
                        tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
                                   "tdb1_open_ex: tdb1_new_database failed!");
                        goto fail;
                }
                goto internal;
        }

        if ((tdb->fd = open(name, open_flags, mode)) == -1) {
                tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
                           "tdb1_open_ex: could not open file %s: %s",
                           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) {
                tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
                           "tdb1_open_ex: failed to get open lock on %s: %s",
                           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) {
                        tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
                                   "tdb1_open_ex: "
                                   "failed to truncate %s: %s",
                                   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) {
                tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
                           "tdb1_open_ex: spinlocks no longer supported");
                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)) {
                tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_USE_ERROR,
                           "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]",
                           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)) {
                tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_USE_ERROR,
                           "tdb1_open_ex: "
                           "%s (%d,%d) is already open in this process",
                           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) {
                        tdb_logerr(tdb, tdb->last_error, TDB_LOG_ERROR,
                                   "tdb1_open_ex: "
                                   "failed to release ACTIVE_LOCK on %s: %s",
                                   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)
                        tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
                                   "tdb1_open_ex: failed to close tdb->fd on error!");
        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;
}