1 files changed, 599 insertions, 0 deletions

diff --git a/src/global/dict_memcache.c b/src/global/dict_memcache.c
new file mode 100644
index 0000000..3210d7d
--- /dev/null
+++ b/src/global/dict_memcache.c
@@ -0,0 +1,599 @@
+/*++
+/* NAME
+/*	dict_memcache 3
+/* SUMMARY
+/*	dictionary interface to memcaches
+/* SYNOPSIS
+/*	#include <dict_memcache.h>
+/*
+/*	DICT	*dict_memcache_open(name, open_flags, dict_flags)
+/*	const char *name;
+/*	int	open_flags;
+/*	int	dict_flags;
+/* DESCRIPTION
+/*	dict_memcache_open() opens a memcache, providing
+/*	a dictionary interface for Postfix key->value mappings.
+/*	The result is a pointer to the installed dictionary.
+/*
+/*	Configuration parameters are described in memcache_table(5).
+/*
+/*	Arguments:
+/* .IP name
+/*	The path to the Postfix memcache configuration file.
+/* .IP open_flags
+/*	O_RDONLY or O_RDWR. This function ignores flags that don't
+/*	specify a read, write or append mode.
+/* .IP dict_flags
+/*	See dict_open(3).
+/* SEE ALSO
+/*	dict(3) generic dictionary manager
+/* HISTORY
+/* .ad
+/* .fi
+/*	The first memcache client for Postfix was written by Omar
+/*	Kilani, and was based on libmemcache.  The current
+/*	implementation implements the memcache protocol directly,
+/*	and bears no resemblance to earlier work.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>			/* XXX sscanf() */
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <dict.h>
+#include <vstring.h>
+#include <stringops.h>
+#include <auto_clnt.h>
+#include <vstream.h>
+
+/* Global library. */
+
+#include <cfg_parser.h>
+#include <db_common.h>
+#include <memcache_proto.h>
+
+/* Application-specific. */
+
+#include <dict_memcache.h>
+
+ /*
+  * Structure of one memcache dictionary handle.
+  */
+typedef struct {
+    DICT    dict;			/* parent class */
+    CFG_PARSER *parser;			/* common parameter parser */
+    void   *dbc_ctxt;			/* db_common context */
+    char   *key_format;			/* query key translation */
+    int     timeout;			/* client timeout */
+    int     mc_ttl;			/* memcache update expiration */
+    int     mc_flags;			/* memcache update flags */
+    int     err_pause;			/* delay between errors */
+    int     max_tries;			/* number of tries */
+    int     max_line;			/* reply line limit */
+    int     max_data;			/* reply data limit */
+    char   *memcache;			/* memcache server spec */
+    AUTO_CLNT *clnt;			/* memcache client stream */
+    VSTRING *clnt_buf;			/* memcache client buffer */
+    VSTRING *key_buf;			/* lookup key */
+    VSTRING *res_buf;			/* lookup result */
+    int     error;			/* memcache dict_errno */
+    DICT   *backup;			/* persistent backup */
+} DICT_MC;
+
+ /*
+  * Memcache option defaults and names.
+  */
+#define DICT_MC_DEF_HOST	"localhost"
+#define DICT_MC_DEF_PORT	"11211"
+#define DICT_MC_DEF_MEMCACHE	"inet:" DICT_MC_DEF_HOST ":" DICT_MC_DEF_PORT
+#define DICT_MC_DEF_KEY_FMT	"%s"
+#define DICT_MC_DEF_MC_TTL	3600
+#define DICT_MC_DEF_MC_TIMEOUT	2
+#define DICT_MC_DEF_MC_FLAGS	0
+#define DICT_MC_DEF_MAX_TRY	2
+#define DICT_MC_DEF_MAX_LINE	1024
+#define DICT_MC_DEF_MAX_DATA	10240
+#define DICT_MC_DEF_ERR_PAUSE	1
+
+#define DICT_MC_NAME_MEMCACHE	"memcache"
+#define DICT_MC_NAME_BACKUP	"backup"
+#define DICT_MC_NAME_KEY_FMT	"key_format"
+#define DICT_MC_NAME_MC_TTL	"ttl"
+#define DICT_MC_NAME_MC_TIMEOUT	"timeout"
+#define DICT_MC_NAME_MC_FLAGS	"flags"
+#define DICT_MC_NAME_MAX_TRY	"max_try"
+#define DICT_MC_NAME_MAX_LINE	"line_size_limit"
+#define DICT_MC_NAME_MAX_DATA	"data_size_limit"
+#define DICT_MC_NAME_ERR_PAUSE	"retry_pause"
+
+ /*
+  * SLMs.
+  */
+#define STR(x)	vstring_str(x)
+#define LEN(x)	VSTRING_LEN(x)
+
+/*#define msg_verbose 1*/
+
+/* dict_memcache_set - set memcache key/value */
+
+static int dict_memcache_set(DICT_MC *dict_mc, const char *value, int ttl)
+{
+    VSTREAM *fp;
+    int     count;
+    size_t  data_len = strlen(value);
+
+    /*
+     * Return a permanent error if we can't store this data. This results in
+     * loss of information.
+     */
+    if (data_len > dict_mc->max_data) {
+	msg_warn("database %s:%s: data for key %s is too long (%s=%d) "
+		 "-- not stored", DICT_TYPE_MEMCACHE, dict_mc->dict.name,
+		 STR(dict_mc->key_buf), DICT_MC_NAME_MAX_DATA,
+		 dict_mc->max_data);
+	/* Not stored! */
+	DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, DICT_STAT_FAIL);
+    }
+    for (count = 0; count < dict_mc->max_tries; count++) {
+	if (count > 0)
+	    sleep(dict_mc->err_pause);
+	if ((fp = auto_clnt_access(dict_mc->clnt)) == 0) {
+	    break;
+	} else if (memcache_printf(fp, "set %s %d %d %ld",
+				   STR(dict_mc->key_buf), dict_mc->mc_flags,
+				   ttl, (long) data_len) < 0
+		   || memcache_fwrite(fp, value, strlen(value)) < 0
+		   || memcache_get(fp, dict_mc->clnt_buf,
+				   dict_mc->max_line) < 0) {
+	    if (count > 0)
+		msg_warn(errno ? "database %s:%s: I/O error: %m" :
+			 "database %s:%s: I/O error",
+			 DICT_TYPE_MEMCACHE, dict_mc->dict.name);
+	} else if (strcmp(STR(dict_mc->clnt_buf), "STORED") != 0) {
+	    if (count > 0)
+		msg_warn("database %s:%s: update failed: %.30s",
+			 DICT_TYPE_MEMCACHE, dict_mc->dict.name,
+			 STR(dict_mc->clnt_buf));
+	} else {
+	    /* Victory! */
+	    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, DICT_STAT_SUCCESS);
+	}
+	auto_clnt_recover(dict_mc->clnt);
+    }
+    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_RETRY, DICT_STAT_ERROR);
+}
+
+/* dict_memcache_get - get memcache key/value */
+
+static const char *dict_memcache_get(DICT_MC *dict_mc)
+{
+    VSTREAM *fp;
+    long    todo;
+    int     count;
+
+    for (count = 0; count < dict_mc->max_tries; count++) {
+	if (count > 0)
+	    sleep(dict_mc->err_pause);
+	if ((fp = auto_clnt_access(dict_mc->clnt)) == 0) {
+	    break;
+	} else if (memcache_printf(fp, "get %s", STR(dict_mc->key_buf)) < 0
+	    || memcache_get(fp, dict_mc->clnt_buf, dict_mc->max_line) < 0) {
+	    if (count > 0)
+		msg_warn(errno ? "database %s:%s: I/O error: %m" :
+			 "database %s:%s: I/O error",
+			 DICT_TYPE_MEMCACHE, dict_mc->dict.name);
+	} else if (strcmp(STR(dict_mc->clnt_buf), "END") == 0) {
+	    /* Not found. */
+	    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, (char *) 0);
+	} else if (sscanf(STR(dict_mc->clnt_buf),
+			  "VALUE %*s %*s %ld", &todo) != 1
+		   || todo < 0 || todo > dict_mc->max_data) {
+	    if (count > 0)
+		msg_warn("%s: unexpected memcache server reply: %.30s",
+			 dict_mc->dict.name, STR(dict_mc->clnt_buf));
+	} else if (memcache_fread(fp, dict_mc->res_buf, todo) < 0) {
+	    if (count > 0)
+		msg_warn("%s: EOF receiving memcache server reply",
+			 dict_mc->dict.name);
+	} else {
+	    /* Victory! */
+	    if (memcache_get(fp, dict_mc->clnt_buf, dict_mc->max_line) < 0
+		|| strcmp(STR(dict_mc->clnt_buf), "END") != 0)
+		auto_clnt_recover(dict_mc->clnt);
+	    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, STR(dict_mc->res_buf));
+	}
+	auto_clnt_recover(dict_mc->clnt);
+    }
+    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_RETRY, (char *) 0);
+}
+
+/* dict_memcache_del - delete memcache key/value */
+
+static int dict_memcache_del(DICT_MC *dict_mc)
+{
+    VSTREAM *fp;
+    int     count;
+
+    for (count = 0; count < dict_mc->max_tries; count++) {
+	if (count > 0)
+	    sleep(dict_mc->err_pause);
+	if ((fp = auto_clnt_access(dict_mc->clnt)) == 0) {
+	    break;
+	} else if (memcache_printf(fp, "delete %s", STR(dict_mc->key_buf)) < 0
+	    || memcache_get(fp, dict_mc->clnt_buf, dict_mc->max_line) < 0) {
+	    if (count > 0)
+		msg_warn(errno ? "database %s:%s: I/O error: %m" :
+			 "database %s:%s: I/O error",
+			 DICT_TYPE_MEMCACHE, dict_mc->dict.name);
+	} else if (strcmp(STR(dict_mc->clnt_buf), "DELETED") == 0) {
+	    /* Victory! */
+	    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, DICT_STAT_SUCCESS);
+	} else if (strcmp(STR(dict_mc->clnt_buf), "NOT_FOUND") == 0) {
+	    /* Not found! */
+	    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, DICT_STAT_FAIL);
+	} else {
+	    if (count > 0)
+		msg_warn("database %s:%s: delete failed: %.30s",
+			 DICT_TYPE_MEMCACHE, dict_mc->dict.name,
+			 STR(dict_mc->clnt_buf));
+	}
+	auto_clnt_recover(dict_mc->clnt);
+    }
+    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_RETRY, DICT_STAT_ERROR);
+}
+
+/* dict_memcache_prepare_key - prepare lookup key */
+
+static ssize_t dict_memcache_prepare_key(DICT_MC *dict_mc, const char *name)
+{
+
+    /*
+     * Optionally case-fold the search string.
+     */
+    if (dict_mc->dict.flags & DICT_FLAG_FOLD_FIX) {
+	if (dict_mc->dict.fold_buf == 0)
+	    dict_mc->dict.fold_buf = vstring_alloc(10);
+	vstring_strcpy(dict_mc->dict.fold_buf, name);
+	name = lowercase(STR(dict_mc->dict.fold_buf));
+    }
+
+    /*
+     * Optionally expand the query key format.
+     */
+#define DICT_MC_NO_KEY		(0)
+#define DICT_MC_NO_QUOTING	((void (*)(DICT *, const char *, VSTRING *)) 0)
+
+    if (dict_mc->key_format != 0
+	&& strcmp(dict_mc->key_format, DICT_MC_DEF_KEY_FMT) != 0) {
+	VSTRING_RESET(dict_mc->key_buf);
+	if (db_common_expand(dict_mc->dbc_ctxt, dict_mc->key_format,
+			     name, DICT_MC_NO_KEY, dict_mc->key_buf,
+			     DICT_MC_NO_QUOTING) == 0)
+	    return (0);
+    } else {
+	vstring_strcpy(dict_mc->key_buf, name);
+    }
+
+    /*
+     * The length indicates whether the expansion is empty or not.
+     */
+    return (LEN(dict_mc->key_buf));
+}
+
+/* dict_memcache_valid_key - validate key */
+
+static int dict_memcache_valid_key(DICT_MC *dict_mc,
+				           const char *name,
+				           const char *operation,
+				        void (*log_func) (const char *,...))
+{
+    unsigned char *cp;
+    int     rc;
+
+#define DICT_MC_SKIP(why) do { \
+	if (msg_verbose || log_func != msg_info) \
+	    log_func("%s: skipping %s for name \"%s\": %s", \
+		     dict_mc->dict.name, operation, name, (why)); \
+	DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, 0); \
+    } while (0)
+
+    if (*name == 0)
+	DICT_MC_SKIP("empty lookup key");
+    if ((rc = db_common_check_domain(dict_mc->dbc_ctxt, name)) == 0)
+	DICT_MC_SKIP("domain mismatch");
+    if (rc < 0)
+	DICT_ERR_VAL_RETURN(dict_mc, rc, 0);
+    if (dict_memcache_prepare_key(dict_mc, name) == 0)
+	DICT_MC_SKIP("empty lookup key expansion");
+    for (cp = (unsigned char *) STR(dict_mc->key_buf); *cp; cp++)
+	if (isascii(*cp) && isspace(*cp))
+	    DICT_MC_SKIP("name contains space");
+
+    DICT_ERR_VAL_RETURN(dict_mc, DICT_ERR_NONE, 1);
+}
+
+/* dict_memcache_update - update memcache */
+
+static int dict_memcache_update(DICT *dict, const char *name,
+				        const char *value)
+{
+    const char *myname = "dict_memcache_update";
+    DICT_MC *dict_mc = (DICT_MC *) dict;
+    DICT   *backup = dict_mc->backup;
+    int     upd_res;
+
+    /*
+     * Skip updates with an inapplicable key, noisily. This results in loss
+     * of information.
+     */
+    if (dict_memcache_valid_key(dict_mc, name, "update", msg_warn) == 0)
+	DICT_ERR_VAL_RETURN(dict, dict_mc->error, DICT_STAT_FAIL);
+
+    /*
+     * Update the memcache first.
+     */
+    upd_res = dict_memcache_set(dict_mc, value, dict_mc->mc_ttl);
+    dict->error = dict_mc->error;
+
+    /*
+     * Update the backup database last.
+     */
+    if (backup) {
+	upd_res = backup->update(backup, name, value);
+	dict->error = backup->error;
+    }
+    if (msg_verbose)
+	msg_info("%s: %s: update key \"%s\"(%s) => \"%s\" %s",
+		 myname, dict_mc->dict.name, name, STR(dict_mc->key_buf),
+		 value, dict_mc->error ? "(memcache error)" : (backup
+		       && backup->error) ? "(backup error)" : "(no error)");
+
+    return (upd_res);
+}
+
+/* dict_memcache_lookup - lookup memcache */
+
+static const char *dict_memcache_lookup(DICT *dict, const char *name)
+{
+    const char *myname = "dict_memcache_lookup";
+    DICT_MC *dict_mc = (DICT_MC *) dict;
+    DICT   *backup = dict_mc->backup;
+    const char *retval;
+
+    /*
+     * Skip lookups with an inapplicable key, silently. This is just asking
+     * for information that cannot exist.
+     */
+    if (dict_memcache_valid_key(dict_mc, name, "lookup", msg_info) == 0)
+	DICT_ERR_VAL_RETURN(dict, dict_mc->error, (char *) 0);
+
+    /*
+     * Search the memcache first.
+     */
+    retval = dict_memcache_get(dict_mc);
+    dict->error = dict_mc->error;
+
+    /*
+     * Search the backup database last. Update the memcache if the data is
+     * found.
+     */
+    if (backup) {
+	backup->error = 0;
+	if (retval == 0) {
+	    retval = backup->lookup(backup, name);
+	    dict->error = backup->error;
+	    /* Update the cache. */
+	    if (retval != 0)
+		dict_memcache_set(dict_mc, retval, dict_mc->mc_ttl);
+	}
+    }
+    if (msg_verbose)
+	msg_info("%s: %s: key \"%s\"(%s) => %s",
+		 myname, dict_mc->dict.name, name, STR(dict_mc->key_buf),
+		 retval ? retval : dict_mc->error ? "(memcache error)" :
+	      (backup && backup->error) ? "(backup error)" : "(not found)");
+
+    return (retval);
+}
+
+/* dict_memcache_delete - delete memcache entry */
+
+static int dict_memcache_delete(DICT *dict, const char *name)
+{
+    const char *myname = "dict_memcache_delete";
+    DICT_MC *dict_mc = (DICT_MC *) dict;
+    DICT   *backup = dict_mc->backup;
+    int     del_res;
+
+    /*
+     * Skip lookups with an inapplicable key, noisily. This is just deleting
+     * information that cannot exist.
+     */
+    if (dict_memcache_valid_key(dict_mc, name, "delete", msg_info) == 0)
+	DICT_ERR_VAL_RETURN(dict, dict_mc->error, dict_mc->error ?
+			    DICT_STAT_ERROR : DICT_STAT_FAIL);
+
+    /*
+     * Update the memcache first.
+     */
+    del_res = dict_memcache_del(dict_mc);
+    dict->error = dict_mc->error;
+
+    /*
+     * Update the persistent database last.
+     */
+    if (backup) {
+	del_res = backup->delete(backup, name);
+	dict->error = backup->error;
+    }
+    if (msg_verbose)
+	msg_info("%s: %s: delete key \"%s\"(%s) => %s",
+		 myname, dict_mc->dict.name, name, STR(dict_mc->key_buf),
+		 dict_mc->error ? "(memcache error)" : (backup
+		       && backup->error) ? "(backup error)" : "(no error)");
+
+    return (del_res);
+}
+
+/* dict_memcache_sequence - first/next lookup */
+
+static int dict_memcache_sequence(DICT *dict, int function, const char **key,
+				          const char **value)
+{
+    const char *myname = "dict_memcache_sequence";
+    DICT_MC *dict_mc = (DICT_MC *) dict;
+    DICT   *backup = dict_mc->backup;
+    int     seq_res;
+
+    if (backup == 0) {
+	msg_warn("database %s:%s: first/next support requires backup database",
+		 DICT_TYPE_MEMCACHE, dict_mc->dict.name);
+	DICT_ERR_VAL_RETURN(dict, DICT_ERR_NONE, DICT_STAT_FAIL);
+    } else {
+	seq_res = backup->sequence(backup, function, key, value);
+	if (msg_verbose)
+	    msg_info("%s: %s: key \"%s\" => %s",
+		     myname, dict_mc->dict.name, *key ? *key : "(not found)",
+		     *value ? *value : backup->error ? "(backup error)" :
+		     "(not found)");
+	DICT_ERR_VAL_RETURN(dict, backup->error, seq_res);
+    }
+}
+
+/* dict_memcache_close - close memcache */
+
+static void dict_memcache_close(DICT *dict)
+{
+    DICT_MC *dict_mc = (DICT_MC *) dict;
+
+    cfg_parser_free(dict_mc->parser);
+    db_common_free_ctx(dict_mc->dbc_ctxt);
+    if (dict_mc->key_format)
+	myfree(dict_mc->key_format);
+    myfree(dict_mc->memcache);
+    auto_clnt_free(dict_mc->clnt);
+    vstring_free(dict_mc->clnt_buf);
+    vstring_free(dict_mc->key_buf);
+    vstring_free(dict_mc->res_buf);
+    if (dict->fold_buf)
+	vstring_free(dict->fold_buf);
+    if (dict_mc->backup)
+	dict_close(dict_mc->backup);
+    dict_free(dict);
+}
+
+/* dict_memcache_open - open memcache */
+
+DICT   *dict_memcache_open(const char *name, int open_flags, int dict_flags)
+{
+    DICT_MC *dict_mc;
+    char   *backup;
+    CFG_PARSER *parser;
+
+    /*
+     * Sanity checks.
+     */
+    if (dict_flags & DICT_FLAG_NO_UNAUTH)
+	return (dict_surrogate(DICT_TYPE_MEMCACHE, name, open_flags, dict_flags,
+		     "%s:%s map is not allowed for security-sensitive data",
+			       DICT_TYPE_MEMCACHE, name));
+    open_flags &= (O_RDONLY | O_RDWR | O_WRONLY | O_APPEND);
+    if (open_flags != O_RDONLY && open_flags != O_RDWR)
+	return (dict_surrogate(DICT_TYPE_MEMCACHE, name, open_flags, dict_flags,
+			"%s:%s map requires O_RDONLY or O_RDWR access mode",
+			       DICT_TYPE_MEMCACHE, name));
+
+    /*
+     * Open the configuration file.
+     */
+    if ((parser = cfg_parser_alloc(name)) == 0)
+	return (dict_surrogate(DICT_TYPE_MEMCACHE, name, open_flags, dict_flags,
+			       "open %s: %m", name));
+
+    /*
+     * Create the dictionary object.
+     */
+    dict_mc = (DICT_MC *) dict_alloc(DICT_TYPE_MEMCACHE, name,
+				     sizeof(*dict_mc));
+    dict_mc->dict.lookup = dict_memcache_lookup;
+    if (open_flags == O_RDWR) {
+	dict_mc->dict.update = dict_memcache_update;
+	dict_mc->dict.delete = dict_memcache_delete;
+    }
+    dict_mc->dict.sequence = dict_memcache_sequence;
+    dict_mc->dict.close = dict_memcache_close;
+    dict_mc->dict.flags = dict_flags;
+    dict_mc->key_buf = vstring_alloc(10);
+    dict_mc->res_buf = vstring_alloc(10);
+
+    /*
+     * Parse the configuration file.
+     */
+    dict_mc->parser = parser;
+    dict_mc->key_format = cfg_get_str(dict_mc->parser, DICT_MC_NAME_KEY_FMT,
+				      DICT_MC_DEF_KEY_FMT, 0, 0);
+    dict_mc->timeout = cfg_get_int(dict_mc->parser, DICT_MC_NAME_MC_TIMEOUT,
+				   DICT_MC_DEF_MC_TIMEOUT, 0, 0);
+    dict_mc->mc_ttl = cfg_get_int(dict_mc->parser, DICT_MC_NAME_MC_TTL,
+				  DICT_MC_DEF_MC_TTL, 0, 0);
+    dict_mc->mc_flags = cfg_get_int(dict_mc->parser, DICT_MC_NAME_MC_FLAGS,
+				    DICT_MC_DEF_MC_FLAGS, 0, 0);
+    dict_mc->err_pause = cfg_get_int(dict_mc->parser, DICT_MC_NAME_ERR_PAUSE,
+				     DICT_MC_DEF_ERR_PAUSE, 1, 0);
+    dict_mc->max_tries = cfg_get_int(dict_mc->parser, DICT_MC_NAME_MAX_TRY,
+				     DICT_MC_DEF_MAX_TRY, 1, 0);
+    dict_mc->max_line = cfg_get_int(dict_mc->parser, DICT_MC_NAME_MAX_LINE,
+				    DICT_MC_DEF_MAX_LINE, 1, 0);
+    dict_mc->max_data = cfg_get_int(dict_mc->parser, DICT_MC_NAME_MAX_DATA,
+				    DICT_MC_DEF_MAX_DATA, 1, 0);
+    dict_mc->memcache = cfg_get_str(dict_mc->parser, DICT_MC_NAME_MEMCACHE,
+				    DICT_MC_DEF_MEMCACHE, 0, 0);
+
+    /*
+     * Initialize the memcache client.
+     */
+    dict_mc->clnt = auto_clnt_create(dict_mc->memcache, dict_mc->timeout, 0, 0);
+    dict_mc->clnt_buf = vstring_alloc(100);
+
+    /*
+     * Open the optional backup database.
+     */
+    backup = cfg_get_str(dict_mc->parser, DICT_MC_NAME_BACKUP,
+			 (char *) 0, 0, 0);
+    if (backup) {
+	dict_mc->backup = dict_open(backup, open_flags, dict_flags);
+	myfree(backup);
+    } else
+	dict_mc->backup = 0;
+
+    /*
+     * Parse templates and common database parameters. Maps that use
+     * substring keys should only be used with the full input key.
+     */
+    dict_mc->dbc_ctxt = 0;
+    db_common_parse(&dict_mc->dict, &dict_mc->dbc_ctxt,
+		    dict_mc->key_format, 1);
+    db_common_parse_domain(dict_mc->parser, dict_mc->dbc_ctxt);
+    if (db_common_dict_partial(dict_mc->dbc_ctxt))
+	/* Breaks recipient delimiters */
+	dict_mc->dict.flags |= DICT_FLAG_PATTERN;
+    else
+	dict_mc->dict.flags |= DICT_FLAG_FIXED;
+
+    dict_mc->dict.flags |= DICT_FLAG_MULTI_WRITER;
+
+    return (&dict_mc->dict);
+}