Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 879 insertions, 0 deletions

diff --git a/src/util/dict_db.c b/src/util/dict_db.c
new file mode 100644
index 0000000..706d397
--- /dev/null
+++ b/src/util/dict_db.c
@@ -0,0 +1,879 @@
+/*++
+/* NAME
+/*	dict_db 3
+/* SUMMARY
+/*	dictionary manager interface to DB files
+/* SYNOPSIS
+/*	#include <dict_db.h>
+/*
+/*	extern int dict_db_cache_size;
+/*
+/*	DEFINE_DICT_DB_CACHE_SIZE;
+/*
+/*	DICT	*dict_hash_open(path, open_flags, dict_flags)
+/*	const char *path;
+/*	int	open_flags;
+/*	int	dict_flags;
+/*
+/*	DICT	*dict_btree_open(path, open_flags, dict_flags)
+/*	const char *path;
+/*	int	open_flags;
+/*	int	dict_flags;
+/* DESCRIPTION
+/*	dict_XXX_open() opens the specified DB database.  The result is
+/*	a pointer to a structure that can be used to access the dictionary
+/*	using the generic methods documented in dict_open(3).
+/*
+/*	The dict_db_cache_size variable specifies a non-default per-table
+/*	I/O buffer size.  The default buffer size is adequate for reading.
+/*	For better performance while creating a large table, specify a large
+/*	buffer size before opening the file.
+/*
+/*	This variable cannot be exported via the dict(3) API and
+/*	must therefore be defined in the calling program by invoking
+/*	the DEFINE_DICT_DB_CACHE_SIZE macro at the global level.
+/*
+/*	Arguments:
+/* .IP path
+/*	The database pathname, not including the ".db" suffix.
+/* .IP open_flags
+/*	Flags passed to dbopen().
+/* .IP dict_flags
+/*	Flags used by the dictionary interface.
+/* SEE ALSO
+/*	dict(3) generic dictionary manager
+/* DIAGNOSTICS
+/*	Fatal errors: cannot open file, write error, out of memory.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+#include "sys_defs.h"
+
+#ifdef HAS_DB
+
+/* System library. */
+
+#include <sys/stat.h>
+#include <limits.h>
+#ifdef PATH_DB_H
+#include PATH_DB_H
+#else
+#include <db.h>
+#endif
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#if defined(_DB_185_H_) && defined(USE_FCNTL_LOCK)
+#error "Error: this system must not use the db 1.85 compatibility interface"
+#endif
+
+#ifndef DB_VERSION_MAJOR
+#define DB_VERSION_MAJOR 1
+#define DICT_DB_GET(db, key, val, flag)	db->get(db, key, val, flag)
+#define DICT_DB_PUT(db, key, val, flag)	db->put(db, key, val, flag)
+#define DICT_DB_DEL(db, key, flag)	db->del(db, key, flag)
+#define DICT_DB_SYNC(db, flag)		db->sync(db, flag)
+#define DICT_DB_CLOSE(db)		db->close(db)
+#define DONT_CLOBBER			R_NOOVERWRITE
+#endif
+
+#if DB_VERSION_MAJOR > 1
+#define DICT_DB_GET(db, key, val, flag)	sanitize(db->get(db, 0, key, val, flag))
+#define DICT_DB_PUT(db, key, val, flag)	sanitize(db->put(db, 0, key, val, flag))
+#define DICT_DB_DEL(db, key, flag)	sanitize(db->del(db, 0, key, flag))
+#define DICT_DB_SYNC(db, flag)		((errno = db->sync(db, flag)) ? -1 : 0)
+#define DICT_DB_CLOSE(db)		((errno = db->close(db, 0)) ? -1 : 0)
+#define DONT_CLOBBER			DB_NOOVERWRITE
+#endif
+
+#if (DB_VERSION_MAJOR == 2 && DB_VERSION_MINOR < 6)
+#define DICT_DB_CURSOR(db, curs)	(db)->cursor((db), NULL, (curs))
+#else
+#define DICT_DB_CURSOR(db, curs)	(db)->cursor((db), NULL, (curs), 0)
+#endif
+
+#ifndef DB_FCNTL_LOCKING
+#define DB_FCNTL_LOCKING		0
+#endif
+
+/* Utility library. */
+
+#include "msg.h"
+#include "mymalloc.h"
+#include "vstring.h"
+#include "stringops.h"
+#include "iostuff.h"
+#include "myflock.h"
+#include "dict.h"
+#include "dict_db.h"
+#include "warn_stat.h"
+
+/* Application-specific. */
+
+typedef struct {
+    DICT    dict;			/* generic members */
+    DB     *db;				/* open db file */
+#if DB_VERSION_MAJOR > 2
+    DB_ENV *dbenv;
+#endif
+#if DB_VERSION_MAJOR > 1
+    DBC    *cursor;			/* dict_db_sequence() */
+#endif
+    VSTRING *key_buf;			/* key result */
+    VSTRING *val_buf;			/* value result */
+} DICT_DB;
+
+#define SCOPY(buf, data, size) \
+    vstring_str(vstring_strncpy(buf ? buf : (buf = vstring_alloc(10)), data, size))
+
+#define DICT_DB_NELM		4096
+
+#if DB_VERSION_MAJOR > 1
+
+/* sanitize - sanitize db_get/put/del result */
+
+static int sanitize(int status)
+{
+
+    /*
+     * XXX This is unclean but avoids a lot of clutter elsewhere. Categorize
+     * results into non-fatal errors (i.e., errors that we can deal with),
+     * success, or fatal error (i.e., all other errors).
+     */
+    switch (status) {
+
+	case DB_NOTFOUND:		/* get, del */
+	case DB_KEYEXIST:		/* put */
+	return (1);			/* non-fatal */
+
+    case 0:
+	return (0);				/* success */
+
+    case DB_KEYEMPTY:				/* get, others? */
+	status = EINVAL;
+	/* FALLTHROUGH */
+    default:
+	errno = status;
+	return (-1);				/* fatal */
+    }
+}
+
+#endif
+
+/* dict_db_lookup - find database entry */
+
+static const char *dict_db_lookup(DICT *dict, const char *name)
+{
+    DICT_DB *dict_db = (DICT_DB *) dict;
+    DB     *db = dict_db->db;
+    DBT     db_key;
+    DBT     db_value;
+    int     status;
+    const char *result = 0;
+
+    dict->error = 0;
+
+    /*
+     * Sanity check.
+     */
+    if ((dict->flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	msg_panic("dict_db_lookup: no DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL flag");
+
+    memset(&db_key, 0, sizeof(db_key));
+    memset(&db_value, 0, sizeof(db_value));
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_FIX) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, name);
+	name = lowercase(vstring_str(dict->fold_buf));
+    }
+
+    /*
+     * Acquire a shared lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_SHARED) < 0)
+	msg_fatal("%s: lock dictionary: %m", dict_db->dict.name);
+
+    /*
+     * See if this DB file was written with one null byte appended to key and
+     * value.
+     */
+    if (dict->flags & DICT_FLAG_TRY1NULL) {
+	db_key.data = (void *) name;
+	db_key.size = strlen(name) + 1;
+	if ((status = DICT_DB_GET(db, &db_key, &db_value, 0)) < 0)
+	    msg_fatal("error reading %s: %m", dict_db->dict.name);
+	if (status == 0) {
+	    dict->flags &= ~DICT_FLAG_TRY0NULL;
+	    result = SCOPY(dict_db->val_buf, db_value.data, db_value.size);
+	}
+    }
+
+    /*
+     * See if this DB file was written with no null byte appended to key and
+     * value.
+     */
+    if (result == 0 && (dict->flags & DICT_FLAG_TRY0NULL)) {
+	db_key.data = (void *) name;
+	db_key.size = strlen(name);
+	if ((status = DICT_DB_GET(db, &db_key, &db_value, 0)) < 0)
+	    msg_fatal("error reading %s: %m", dict_db->dict.name);
+	if (status == 0) {
+	    dict->flags &= ~DICT_FLAG_TRY1NULL;
+	    result = SCOPY(dict_db->val_buf, db_value.data, db_value.size);
+	}
+    }
+
+    /*
+     * Release the shared lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_NONE) < 0)
+	msg_fatal("%s: unlock dictionary: %m", dict_db->dict.name);
+
+    return (result);
+}
+
+/* dict_db_update - add or update database entry */
+
+static int dict_db_update(DICT *dict, const char *name, const char *value)
+{
+    DICT_DB *dict_db = (DICT_DB *) dict;
+    DB     *db = dict_db->db;
+    DBT     db_key;
+    DBT     db_value;
+    int     status;
+
+    dict->error = 0;
+
+    /*
+     * Sanity check.
+     */
+    if ((dict->flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	msg_panic("dict_db_update: no DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL flag");
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_FIX) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, name);
+	name = lowercase(vstring_str(dict->fold_buf));
+    }
+    memset(&db_key, 0, sizeof(db_key));
+    memset(&db_value, 0, sizeof(db_value));
+    db_key.data = (void *) name;
+    db_value.data = (void *) value;
+    db_key.size = strlen(name);
+    db_value.size = strlen(value);
+
+    /*
+     * If undecided about appending a null byte to key and value, choose a
+     * default depending on the platform.
+     */
+    if ((dict->flags & DICT_FLAG_TRY1NULL)
+	&& (dict->flags & DICT_FLAG_TRY0NULL)) {
+#ifdef DB_NO_TRAILING_NULL
+	dict->flags &= ~DICT_FLAG_TRY1NULL;
+#else
+	dict->flags &= ~DICT_FLAG_TRY0NULL;
+#endif
+    }
+
+    /*
+     * Optionally append a null byte to key and value.
+     */
+    if (dict->flags & DICT_FLAG_TRY1NULL) {
+	db_key.size++;
+	db_value.size++;
+    }
+
+    /*
+     * Acquire an exclusive lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0)
+	msg_fatal("%s: lock dictionary: %m", dict_db->dict.name);
+
+    /*
+     * Do the update.
+     */
+    if ((status = DICT_DB_PUT(db, &db_key, &db_value,
+	     (dict->flags & DICT_FLAG_DUP_REPLACE) ? 0 : DONT_CLOBBER)) < 0)
+	msg_fatal("error writing %s: %m", dict_db->dict.name);
+    if (status) {
+	if (dict->flags & DICT_FLAG_DUP_IGNORE)
+	     /* void */ ;
+	else if (dict->flags & DICT_FLAG_DUP_WARN)
+	    msg_warn("%s: duplicate entry: \"%s\"", dict_db->dict.name, name);
+	else
+	    msg_fatal("%s: duplicate entry: \"%s\"", dict_db->dict.name, name);
+    }
+    if (dict->flags & DICT_FLAG_SYNC_UPDATE)
+	if (DICT_DB_SYNC(db, 0) < 0)
+	    msg_fatal("%s: flush dictionary: %m", dict_db->dict.name);
+
+    /*
+     * Release the exclusive lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_NONE) < 0)
+	msg_fatal("%s: unlock dictionary: %m", dict_db->dict.name);
+
+    return (status);
+}
+
+/* delete one entry from the dictionary */
+
+static int dict_db_delete(DICT *dict, const char *name)
+{
+    DICT_DB *dict_db = (DICT_DB *) dict;
+    DB     *db = dict_db->db;
+    DBT     db_key;
+    int     status = 1;
+    int     flags = 0;
+
+    dict->error = 0;
+
+    /*
+     * Sanity check.
+     */
+    if ((dict->flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	msg_panic("dict_db_delete: no DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL flag");
+
+    /*
+     * Optionally fold the key.
+     */
+    if (dict->flags & DICT_FLAG_FOLD_FIX) {
+	if (dict->fold_buf == 0)
+	    dict->fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict->fold_buf, name);
+	name = lowercase(vstring_str(dict->fold_buf));
+    }
+    memset(&db_key, 0, sizeof(db_key));
+
+    /*
+     * Acquire an exclusive lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0)
+	msg_fatal("%s: lock dictionary: %m", dict_db->dict.name);
+
+    /*
+     * See if this DB file was written with one null byte appended to key and
+     * value.
+     */
+    if (dict->flags & DICT_FLAG_TRY1NULL) {
+	db_key.data = (void *) name;
+	db_key.size = strlen(name) + 1;
+	if ((status = DICT_DB_DEL(db, &db_key, flags)) < 0)
+	    msg_fatal("error deleting from %s: %m", dict_db->dict.name);
+	if (status == 0)
+	    dict->flags &= ~DICT_FLAG_TRY0NULL;
+    }
+
+    /*
+     * See if this DB file was written with no null byte appended to key and
+     * value.
+     */
+    if (status > 0 && (dict->flags & DICT_FLAG_TRY0NULL)) {
+	db_key.data = (void *) name;
+	db_key.size = strlen(name);
+	if ((status = DICT_DB_DEL(db, &db_key, flags)) < 0)
+	    msg_fatal("error deleting from %s: %m", dict_db->dict.name);
+	if (status == 0)
+	    dict->flags &= ~DICT_FLAG_TRY1NULL;
+    }
+    if (dict->flags & DICT_FLAG_SYNC_UPDATE)
+	if (DICT_DB_SYNC(db, 0) < 0)
+	    msg_fatal("%s: flush dictionary: %m", dict_db->dict.name);
+
+    /*
+     * Release the exclusive lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_NONE) < 0)
+	msg_fatal("%s: unlock dictionary: %m", dict_db->dict.name);
+
+    return status;
+}
+
+/* dict_db_sequence - traverse the dictionary */
+
+static int dict_db_sequence(DICT *dict, int function,
+			            const char **key, const char **value)
+{
+    const char *myname = "dict_db_sequence";
+    DICT_DB *dict_db = (DICT_DB *) dict;
+    DB     *db = dict_db->db;
+    DBT     db_key;
+    DBT     db_value;
+    int     status = 0;
+    int     db_function;
+
+    dict->error = 0;
+
+#if DB_VERSION_MAJOR > 1
+
+    /*
+     * Initialize.
+     */
+    memset(&db_key, 0, sizeof(db_key));
+    memset(&db_value, 0, sizeof(db_value));
+
+    /*
+     * Determine the function.
+     */
+    switch (function) {
+    case DICT_SEQ_FUN_FIRST:
+	if (dict_db->cursor == 0)
+	    DICT_DB_CURSOR(db, &(dict_db->cursor));
+	db_function = DB_FIRST;
+	break;
+    case DICT_SEQ_FUN_NEXT:
+	if (dict_db->cursor == 0)
+	    msg_panic("%s: no cursor", myname);
+	db_function = DB_NEXT;
+	break;
+    default:
+	msg_panic("%s: invalid function %d", myname, function);
+    }
+
+    /*
+     * Acquire a shared lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_SHARED) < 0)
+	msg_fatal("%s: lock dictionary: %m", dict_db->dict.name);
+
+    /*
+     * Database lookup.
+     */
+    status =
+	dict_db->cursor->c_get(dict_db->cursor, &db_key, &db_value, db_function);
+    if (status != 0 && status != DB_NOTFOUND)
+	msg_fatal("error [%d] seeking %s: %m", status, dict_db->dict.name);
+
+    /*
+     * Release the shared lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_NONE) < 0)
+	msg_fatal("%s: unlock dictionary: %m", dict_db->dict.name);
+
+    if (status == 0) {
+
+	/*
+	 * Copy the result so it is guaranteed null terminated.
+	 */
+	*key = SCOPY(dict_db->key_buf, db_key.data, db_key.size);
+	*value = SCOPY(dict_db->val_buf, db_value.data, db_value.size);
+    }
+    return (status);
+#else
+
+    /*
+     * determine the function
+     */
+    switch (function) {
+    case DICT_SEQ_FUN_FIRST:
+	db_function = R_FIRST;
+	break;
+    case DICT_SEQ_FUN_NEXT:
+	db_function = R_NEXT;
+	break;
+    default:
+	msg_panic("%s: invalid function %d", myname, function);
+    }
+
+    /*
+     * Acquire a shared lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_SHARED) < 0)
+	msg_fatal("%s: lock dictionary: %m", dict_db->dict.name);
+
+    if ((status = db->seq(db, &db_key, &db_value, db_function)) < 0)
+	msg_fatal("error seeking %s: %m", dict_db->dict.name);
+
+    /*
+     * Release the shared lock.
+     */
+    if ((dict->flags & DICT_FLAG_LOCK)
+	&& myflock(dict->lock_fd, INTERNAL_LOCK, MYFLOCK_OP_NONE) < 0)
+	msg_fatal("%s: unlock dictionary: %m", dict_db->dict.name);
+
+    if (status == 0) {
+
+	/*
+	 * Copy the result so that it is guaranteed null terminated.
+	 */
+	*key = SCOPY(dict_db->key_buf, db_key.data, db_key.size);
+	*value = SCOPY(dict_db->val_buf, db_value.data, db_value.size);
+    }
+    return status;
+#endif
+}
+
+/* dict_db_close - close data base */
+
+static void dict_db_close(DICT *dict)
+{
+    DICT_DB *dict_db = (DICT_DB *) dict;
+
+#if DB_VERSION_MAJOR > 1
+    if (dict_db->cursor)
+	dict_db->cursor->c_close(dict_db->cursor);
+#endif
+    if (DICT_DB_SYNC(dict_db->db, 0) < 0)
+	msg_fatal("flush database %s: %m", dict_db->dict.name);
+
+    /*
+     * With some Berkeley DB implementations, close fails with a bogus ENOENT
+     * error, while it reports no errors with put+sync, no errors with
+     * del+sync, and no errors with the sync operation just before this
+     * comment. This happens in programs that never fork and that never share
+     * the database with other processes. The bogus close error has been
+     * reported for programs that use the first/next iterator. Instead of
+     * making Postfix look bad because it reports errors that other programs
+     * ignore, I'm going to report the bogus error as a non-error.
+     */
+    if (DICT_DB_CLOSE(dict_db->db) < 0)
+	msg_info("close database %s: %m (possible Berkeley DB bug)",
+		 dict_db->dict.name);
+#if DB_VERSION_MAJOR > 2
+    dict_db->dbenv->close(dict_db->dbenv, 0);
+#endif
+    if (dict_db->key_buf)
+	vstring_free(dict_db->key_buf);
+    if (dict_db->val_buf)
+	vstring_free(dict_db->val_buf);
+    if (dict->fold_buf)
+	vstring_free(dict->fold_buf);
+    dict_free(dict);
+}
+
+#if DB_VERSION_MAJOR > 2
+
+/* dict_db_new_env - workaround for undocumented ./DB_CONFIG read */
+
+static DB_ENV *dict_db_new_env(const char *db_path)
+{
+    VSTRING *db_home_buf;
+    DB_ENV *dbenv;
+    u_int32_t cache_size_gbytes;
+    u_int32_t cache_size_bytes;
+    int     ncache;
+
+    if ((errno = db_env_create(&dbenv, 0)) != 0)
+	msg_fatal("create DB environment: %m");
+#if DB_VERSION_MAJOR > 4 || (DB_VERSION_MAJOR == 4 && DB_VERSION_MINOR >= 7)
+    if ((errno = dbenv->get_cachesize(dbenv, &cache_size_gbytes,
+				      &cache_size_bytes, &ncache)) != 0)
+	msg_fatal("get DB cache size: %m");
+    if (cache_size_gbytes == 0 && cache_size_bytes < dict_db_cache_size) {
+	if ((errno = dbenv->set_cache_max(dbenv, cache_size_gbytes,
+					  dict_db_cache_size)) != 0)
+	    msg_fatal("set DB max cache size %d: %m", dict_db_cache_size);
+	if ((errno = dbenv->set_cachesize(dbenv, cache_size_gbytes,
+					  dict_db_cache_size, ncache)) != 0)
+	    msg_fatal("set DB cache size %d: %m", dict_db_cache_size);
+    }
+#endif
+    /* XXX db_home is also the default directory for the .db file. */
+    db_home_buf = vstring_alloc(100);
+    if ((errno = dbenv->open(dbenv, sane_dirname(db_home_buf, db_path),
+			   DB_INIT_MPOOL | DB_CREATE | DB_PRIVATE, 0)) != 0)
+	msg_fatal("open DB environment: %m");
+    vstring_free(db_home_buf);
+    return (dbenv);
+}
+
+#endif
+
+/* dict_db_open - open data base */
+
+static DICT *dict_db_open(const char *class, const char *path, int open_flags,
+			          int type, void *tweak, int dict_flags)
+{
+    DICT_DB *dict_db;
+    struct stat st;
+    DB     *db = 0;
+    char   *db_path = 0;
+    VSTRING *db_base_buf = 0;
+    int     lock_fd = -1;
+    int     dbfd;
+
+#if DB_VERSION_MAJOR > 1
+    int     db_flags;
+
+#endif
+#if DB_VERSION_MAJOR > 2
+    DB_ENV *dbenv = 0;
+
+#endif
+
+    /*
+     * Mismatches between #include file and library are a common cause for
+     * trouble.
+     */
+#if DB_VERSION_MAJOR > 1
+    int     major_version;
+    int     minor_version;
+    int     patch_version;
+
+    (void) db_version(&major_version, &minor_version, &patch_version);
+    if (major_version != DB_VERSION_MAJOR || minor_version != DB_VERSION_MINOR)
+	return (dict_surrogate(class, path, open_flags, dict_flags,
+			       "incorrect version of Berkeley DB: "
+	      "compiled against %d.%d.%d, run-time linked against %d.%d.%d",
+		       DB_VERSION_MAJOR, DB_VERSION_MINOR, DB_VERSION_PATCH,
+			       major_version, minor_version, patch_version));
+    if (msg_verbose) {
+	msg_info("Compiled against Berkeley DB: %d.%d.%d\n",
+		 DB_VERSION_MAJOR, DB_VERSION_MINOR, DB_VERSION_PATCH);
+	msg_info("Run-time linked against Berkeley DB: %d.%d.%d\n",
+		 major_version, minor_version, patch_version);
+    }
+#else
+    if (msg_verbose)
+	msg_info("Compiled against Berkeley DB version 1");
+#endif
+
+    db_path = concatenate(path, ".db", (char *) 0);
+
+    /*
+     * Note: DICT_FLAG_LOCK is used only by programs that do fine-grained (in
+     * the time domain) locking while accessing individual database records.
+     * 
+     * Programs such as postmap/postalias use their own large-grained (in the
+     * time domain) locks while rewriting the entire file.
+     * 
+     * XXX DB version 4.1 will not open a zero-length file. This means we must
+     * open an existing file without O_CREAT|O_TRUNC, and that we must let
+     * db_open() create a non-existent file for us.
+     */
+#define LOCK_OPEN_FLAGS(f) ((f) & ~(O_CREAT|O_TRUNC))
+#if DB_VERSION_MAJOR <= 2
+#define FREE_RETURN(e) do { \
+	DICT *_dict = (e); if (db) DICT_DB_CLOSE(db); \
+	if (lock_fd >= 0) (void) close(lock_fd); \
+	if (db_base_buf) vstring_free(db_base_buf); \
+	if (db_path) myfree(db_path); return (_dict); \
+    } while (0)
+#else
+#define FREE_RETURN(e) do { \
+	DICT *_dict = (e); if (db) DICT_DB_CLOSE(db); \
+	if (dbenv) dbenv->close(dbenv, 0); \
+	if (lock_fd >= 0) (void) close(lock_fd); \
+	if (db_base_buf) vstring_free(db_base_buf); \
+	if (db_path) myfree(db_path); return (_dict); \
+    } while (0)
+#endif
+
+    if (dict_flags & DICT_FLAG_LOCK) {
+	if ((lock_fd = open(db_path, LOCK_OPEN_FLAGS(open_flags), 0644)) < 0) {
+	    if (errno != ENOENT)
+		FREE_RETURN(dict_surrogate(class, path, open_flags, dict_flags,
+					   "open database %s: %m", db_path));
+	} else {
+	    if (myflock(lock_fd, INTERNAL_LOCK, MYFLOCK_OP_SHARED) < 0)
+		msg_fatal("shared-lock database %s for open: %m", db_path);
+	}
+    }
+
+    /*
+     * Use the DB 1.x programming interface. This is the default interface
+     * with 4.4BSD systems. It is also available via the db_185 compatibility
+     * interface, but that interface does not have the undocumented feature
+     * that we need to make file locking safe with POSIX fcntl() locking.
+     */
+#if DB_VERSION_MAJOR < 2
+    if ((db = dbopen(db_path, open_flags, 0644, type, tweak)) == 0)
+	FREE_RETURN(dict_surrogate(class, path, open_flags, dict_flags,
+				   "open database %s: %m", db_path));
+    dbfd = db->fd(db);
+#endif
+
+    /*
+     * Use the DB 2.x programming interface. Jump a couple extra hoops.
+     */
+#if DB_VERSION_MAJOR == 2
+    db_flags = DB_FCNTL_LOCKING;
+    if (open_flags == O_RDONLY)
+	db_flags |= DB_RDONLY;
+    if (open_flags & O_CREAT)
+	db_flags |= DB_CREATE;
+    if (open_flags & O_TRUNC)
+	db_flags |= DB_TRUNCATE;
+    if ((errno = db_open(db_path, type, db_flags, 0644, 0, tweak, &db)) != 0)
+	FREE_RETURN(dict_surrogate(class, path, open_flags, dict_flags,
+				   "open database %s: %m", db_path));
+    if (db == 0)
+	msg_panic("db_open null result");
+    if ((errno = db->fd(db, &dbfd)) != 0)
+	msg_fatal("get database file descriptor: %m");
+#endif
+
+    /*
+     * Use the DB 3.x programming interface. Jump even more hoops.
+     */
+#if DB_VERSION_MAJOR > 2
+    db_flags = DB_FCNTL_LOCKING;
+    if (open_flags == O_RDONLY)
+	db_flags |= DB_RDONLY;
+    if (open_flags & O_CREAT)
+	db_flags |= DB_CREATE;
+    if (open_flags & O_TRUNC)
+	db_flags |= DB_TRUNCATE;
+    if ((errno = db_create(&db, dbenv = dict_db_new_env(db_path), 0)) != 0)
+	msg_fatal("create DB database: %m");
+    if (db == 0)
+	msg_panic("db_create null result");
+    if (type == DB_HASH && db->set_h_nelem(db, DICT_DB_NELM) != 0)
+	msg_fatal("set DB hash element count %d: %m", DICT_DB_NELM);
+    db_base_buf = vstring_alloc(100);
+#if DB_VERSION_MAJOR == 6 || DB_VERSION_MAJOR == 5 || \
+	(DB_VERSION_MAJOR == 4 && DB_VERSION_MINOR > 0)
+    if ((errno = db->open(db, 0, sane_basename(db_base_buf, db_path),
+			  0, type, db_flags, 0644)) != 0)
+	FREE_RETURN(dict_surrogate(class, path, open_flags, dict_flags,
+				   "open database %s: %m", db_path));
+#elif (DB_VERSION_MAJOR == 3 || DB_VERSION_MAJOR == 4)
+    if ((errno = db->open(db, sane_basename(db_base_buf, db_path), 0,
+			  type, db_flags, 0644)) != 0)
+	FREE_RETURN(dict_surrogate(class, path, open_flags, dict_flags,
+				   "open database %s: %m", db_path));
+#else
+#error "Unsupported Berkeley DB version"
+#endif
+    vstring_free(db_base_buf);
+    if ((errno = db->fd(db, &dbfd)) != 0)
+	msg_fatal("get database file descriptor: %m");
+#endif
+    if ((dict_flags & DICT_FLAG_LOCK) && lock_fd >= 0) {
+	if (myflock(lock_fd, INTERNAL_LOCK, MYFLOCK_OP_NONE) < 0)
+	    msg_fatal("unlock database %s for open: %m", db_path);
+	if (close(lock_fd) < 0)
+	    msg_fatal("close database %s: %m", db_path);
+	lock_fd = -1;
+    }
+    dict_db = (DICT_DB *) dict_alloc(class, db_path, sizeof(*dict_db));
+    dict_db->dict.lookup = dict_db_lookup;
+    dict_db->dict.update = dict_db_update;
+    dict_db->dict.delete = dict_db_delete;
+    dict_db->dict.sequence = dict_db_sequence;
+    dict_db->dict.close = dict_db_close;
+    dict_db->dict.lock_fd = dbfd;
+    dict_db->dict.stat_fd = dbfd;
+    if (fstat(dict_db->dict.stat_fd, &st) < 0)
+	msg_fatal("dict_db_open: fstat: %m");
+    dict_db->dict.mtime = st.st_mtime;
+    dict_db->dict.owner.uid = st.st_uid;
+    dict_db->dict.owner.status = (st.st_uid != 0);
+
+    /*
+     * Warn if the source file is newer than the indexed file, except when
+     * the source file changed only seconds ago.
+     */
+    if ((dict_flags & DICT_FLAG_LOCK) != 0
+	&& stat(path, &st) == 0
+	&& st.st_mtime > dict_db->dict.mtime
+	&& st.st_mtime < time((time_t *) 0) - 100)
+	msg_warn("database %s is older than source file %s", db_path, path);
+
+    close_on_exec(dict_db->dict.lock_fd, CLOSE_ON_EXEC);
+    close_on_exec(dict_db->dict.stat_fd, CLOSE_ON_EXEC);
+    dict_db->dict.flags = dict_flags | DICT_FLAG_FIXED;
+    if ((dict_flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
+	dict_db->dict.flags |= (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL);
+    if (dict_flags & DICT_FLAG_FOLD_FIX)
+	dict_db->dict.fold_buf = vstring_alloc(10);
+    dict_db->db = db;
+#if DB_VERSION_MAJOR > 2
+    dict_db->dbenv = dbenv;
+#endif
+#if DB_VERSION_MAJOR > 1
+    dict_db->cursor = 0;
+#endif
+    dict_db->key_buf = 0;
+    dict_db->val_buf = 0;
+
+    myfree(db_path);
+    return (DICT_DEBUG (&dict_db->dict));
+}
+
+/* dict_hash_open - create association with data base */
+
+DICT   *dict_hash_open(const char *path, int open_flags, int dict_flags)
+{
+#if DB_VERSION_MAJOR < 2
+    HASHINFO tweak;
+
+    memset((void *) &tweak, 0, sizeof(tweak));
+    tweak.nelem = DICT_DB_NELM;
+    tweak.cachesize = dict_db_cache_size;
+#endif
+#if DB_VERSION_MAJOR == 2
+    DB_INFO tweak;
+
+    memset((void *) &tweak, 0, sizeof(tweak));
+    tweak.h_nelem = DICT_DB_NELM;
+    tweak.db_cachesize = dict_db_cache_size;
+#endif
+#if DB_VERSION_MAJOR > 2
+    void   *tweak;
+
+    tweak = 0;
+#endif
+    return (dict_db_open(DICT_TYPE_HASH, path, open_flags, DB_HASH,
+			 (void *) &tweak, dict_flags));
+}
+
+/* dict_btree_open - create association with data base */
+
+DICT   *dict_btree_open(const char *path, int open_flags, int dict_flags)
+{
+#if DB_VERSION_MAJOR < 2
+    BTREEINFO tweak;
+
+    memset((void *) &tweak, 0, sizeof(tweak));
+    tweak.cachesize = dict_db_cache_size;
+#endif
+#if DB_VERSION_MAJOR == 2
+    DB_INFO tweak;
+
+    memset((void *) &tweak, 0, sizeof(tweak));
+    tweak.db_cachesize = dict_db_cache_size;
+#endif
+#if DB_VERSION_MAJOR > 2
+    void   *tweak;
+
+    tweak = 0;
+#endif
+
+    return (dict_db_open(DICT_TYPE_BTREE, path, open_flags, DB_BTREE,
+			 (void *) &tweak, dict_flags));
+}
+
+#endif