/*++
/* NAME
/*	postalias 1
/* SUMMARY
/*	Postfix alias database maintenance
/* SYNOPSIS
/* .fi
/*	\fBpostalias\fR [\fB-Nfinoprsuvw\fR] [\fB-c \fIconfig_dir\fR]
/*	[\fB-d \fIkey\fR] [\fB-q \fIkey\fR]
/*		[\fIfile_type\fR:]\fIfile_name\fR ...
/* DESCRIPTION
/*	The \fBpostalias\fR(1) command creates or queries one or more Postfix
/*	alias databases, or updates an existing one. The input and output
/*	file formats are expected to be compatible with Sendmail version 8,
/*	and are expected to be suitable for use as NIS alias maps.
/*
/*	If the result files do not exist they will be created with the
/*	same group and other read permissions as their source file.
/*
/*	While a database update is in progress, signal delivery is
/*	postponed, and an exclusive, advisory, lock is placed on the
/*	entire database, in order to avoid surprises in spectator
/*	processes.
/*
/*	The format of Postfix alias input files is described in
/*	\fBaliases\fR(5).
/*
/*	By default the lookup key is mapped to lowercase to make
/*	the lookups case insensitive; as of Postfix 2.3 this case
/*	folding happens only with tables whose lookup keys are
/*	fixed-case strings such as btree:, dbm: or hash:. With
/*	earlier versions, the lookup key is folded even with tables
/*	where a lookup field can match both upper and lower case
/*	text, such as regexp: and pcre:. This resulted in loss of
/*	information with $\fInumber\fR substitutions.
/*
/*	Options:
/* .IP "\fB-c \fIconfig_dir\fR"
/*	Read the \fBmain.cf\fR configuration file in the named directory
/*	instead of the default configuration directory.
/* .IP "\fB-d \fIkey\fR"
/*	Search the specified maps for \fIkey\fR and remove one entry per map.
/*	The exit status is zero when the requested information was found.
/*
/*	If a key value of \fB-\fR is specified, the program reads key
/*	values from the standard input stream. The exit status is zero
/*	when at least one of the requested keys was found.
/* .IP \fB-f\fR
/*	Do not fold the lookup key to lower case while creating or querying
/*	a table.
/*
/*	With Postfix version 2.3 and later, this option has no
/*	effect for regular expression tables. There, case folding
/*	is controlled by appending a flag to a pattern.
/* .IP \fB-i\fR
/*	Incremental mode. Read entries from standard input and do not
/*	truncate an existing database. By default, \fBpostalias\fR(1) creates
/*	a new database from the entries in \fIfile_name\fR.
/* .IP \fB-N\fR
/*	Include the terminating null character that terminates lookup keys
/*	and values. By default, \fBpostalias\fR(1) does whatever
/*	is the default for
/*	the host operating system.
/* .IP \fB-n\fR
/*	Don't include the terminating null character that terminates lookup
/*	keys and values. By default, \fBpostalias\fR(1) does whatever
/*	is the default for
/*	the host operating system.
/* .IP \fB-o\fR
/*	Do not release root privileges when processing a non-root
/*	input file. By default, \fBpostalias\fR(1) drops root privileges
/*	and runs as the source file owner instead.
/* .IP \fB-p\fR
/*	Do not inherit the file access permissions from the input file
/*	when creating a new file.  Instead, create a new file with default
/*	access permissions (mode 0644).
/* .IP "\fB-q \fIkey\fR"
/*	Search the specified maps for \fIkey\fR and write the first value
/*	found to the standard output stream. The exit status is zero
/*	when the requested information was found.
/*
/*	Note: this performs a single query with the key as specified,
/*	and does not make iterative queries with substrings of the
/*	key as described in the aliases(5) manual page.
/*
/*	If a key value of \fB-\fR is specified, the program reads key
/*	values from the standard input stream and writes one line of
/*	\fIkey: value\fR output for each key that was found. The exit
/*	status is zero when at least one of the requested keys was found.
/* .IP \fB-r\fR
/*	When updating a table, do not complain about attempts to update
/*	existing entries, and make those updates anyway.
/* .IP \fB-s\fR
/*	Retrieve all database elements, and write one line of
/*	\fIkey: value\fR output for each element. The elements are
/*	printed in database order, which is not necessarily the same
/*	as the original input order.
/*	This feature is available in Postfix version 2.2 and later,
/*	and is not available for all database types.
/* .IP \fB-u\fR
/*	Disable UTF-8 support. UTF-8 support is enabled by default
/*	when "smtputf8_enable = yes". It requires that keys and
/*	values are valid UTF-8 strings.
/* .IP \fB-v\fR
/*	Enable verbose logging for debugging purposes. Multiple \fB-v\fR
/*	options make the software increasingly verbose.
/* .IP \fB-w\fR
/*	When updating a table, do not complain about attempts to update
/*	existing entries, and ignore those attempts.
/* .PP
/*	Arguments:
/* .IP \fIfile_type\fR
/*	The database type. To find out what types are supported, use
/*	the "\fBpostconf -m\fR" command.
/*
/*	The \fBpostalias\fR(1) command can query any supported file type,
/*	but it can create only the following file types:
/* .RS
/* .IP \fBbtree\fR
/*	The output is a btree file, named \fIfile_name\fB.db\fR.
/*	This is available on systems with support for \fBdb\fR databases.
/* .IP \fBcdb\fR
/*	The output is one file named \fIfile_name\fB.cdb\fR.
/*	This is available on systems with support for \fBcdb\fR databases.
/* .IP \fBdbm\fR
/*	The output consists of two files, named \fIfile_name\fB.pag\fR and
/*	\fIfile_name\fB.dir\fR.
/*	This is available on systems with support for \fBdbm\fR databases.
/* .IP \fBfail\fR
/*	A table that reliably fails all requests. The lookup table
/*	name is used for logging only. This table exists to simplify
/*	Postfix error tests.
/* .IP \fBhash\fR
/*	The output is a hashed file, named \fIfile_name\fB.db\fR.
/*	This is available on systems with support for \fBdb\fR databases.
/* .IP \fBlmdb\fR
/*	The output is a btree-based file, named \fIfile_name\fB.lmdb\fR.
/*	\fBlmdb\fR supports concurrent writes and reads from different
/*	processes, unlike other supported file-based tables.
/*	This is available on systems with support for \fBlmdb\fR databases.
/* .IP \fBsdbm\fR
/*	The output consists of two files, named \fIfile_name\fB.pag\fR and
/*	\fIfile_name\fB.dir\fR.
/*	This is available on systems with support for \fBsdbm\fR databases.
/* .PP
/*	When no \fIfile_type\fR is specified, the software uses the database
/*	type specified via the \fBdefault_database_type\fR configuration
/*	parameter.
/*	The default value for this parameter depends on the host environment.
/* .RE
/* .IP \fIfile_name\fR
/*	The name of the alias database source file when creating a database.
/* DIAGNOSTICS
/*	Problems are logged to the standard error stream and to
/*	\fBsyslogd\fR(8) or \fBpostlogd\fR(8). No output means that
/*	no problems were detected. Duplicate entries are skipped and are
/*	flagged with a warning.
/*
/*	\fBpostalias\fR(1) terminates with zero exit status in case of success
/*	(including successful "\fBpostalias -q\fR" lookup) and terminates
/*	with non-zero exit status in case of failure.
/* ENVIRONMENT
/* .ad
/* .fi
/* .IP \fBMAIL_CONFIG\fR
/*	Directory with Postfix configuration files.
/* .IP \fBMAIL_VERBOSE\fR
/*	Enable verbose logging for debugging purposes.
/* CONFIGURATION PARAMETERS
/* .ad
/* .fi
/*	The following \fBmain.cf\fR parameters are especially relevant to
/*	this program.
/*
/*	The text below provides only a parameter summary. See
/*	\fBpostconf\fR(5) for more details including examples.
/* .IP "\fBalias_database (see 'postconf -d' output)\fR"
/*	The alias databases for \fBlocal\fR(8) delivery that are updated with
/*	"\fBnewaliases\fR" or with "\fBsendmail -bi\fR".
/* .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
/*	The default location of the Postfix main.cf and master.cf
/*	configuration files.
/* .IP "\fBberkeley_db_create_buffer_size (16777216)\fR"
/*	The per-table I/O buffer size for programs that create Berkeley DB
/*	hash or btree tables.
/* .IP "\fBberkeley_db_read_buffer_size (131072)\fR"
/*	The per-table I/O buffer size for programs that read Berkeley DB
/*	hash or btree tables.
/* .IP "\fBdefault_database_type (see 'postconf -d' output)\fR"
/*	The default database type for use in \fBnewaliases\fR(1), \fBpostalias\fR(1)
/*	and \fBpostmap\fR(1) commands.
/* .IP "\fBimport_environment (see 'postconf -d' output)\fR"
/*	The list of environment variables that a privileged Postfix
/*	process will import from a non-Postfix parent process, or name=value
/*	environment overrides.
/* .IP "\fBsmtputf8_enable (yes)\fR"
/*	Enable preliminary SMTPUTF8 support for the protocols described
/*	in RFC 6531, RFC 6532, and RFC 6533.
/* .IP "\fBsyslog_facility (mail)\fR"
/*	The syslog facility of Postfix logging.
/* .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
/*	A prefix that is prepended to the process name in syslog
/*	records, so that, for example, "smtpd" becomes "prefix/smtpd".
/* .PP
/*	Available in Postfix 2.11 and later:
/* .IP "\fBlmdb_map_size (16777216)\fR"
/*	The initial OpenLDAP LMDB database size limit in bytes.
/* STANDARDS
/*	RFC 822 (ARPA Internet Text Messages)
/* SEE ALSO
/*	aliases(5), format of alias database input file.
/*	local(8), Postfix local delivery agent.
/*	postconf(1), supported database types
/*	postconf(5), configuration parameters
/*	postmap(1), create/update/query lookup tables
/*	newaliases(1), Sendmail compatibility interface.
/*	postlogd(8), Postfix logging
/*	syslogd(8), system logging
/* README FILES
/* .ad
/* .fi
/*	Use "\fBpostconf readme_directory\fR" or
/*	"\fBpostconf html_directory\fR" to locate this information.
/* .na
/* .nf
/*	DATABASE_README, Postfix lookup table overview
/* 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
/*--*/

/* System library. */

#include <sys_defs.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include <string.h>

/* Utility library. */

#include <msg.h>
#include <mymalloc.h>
#include <vstring.h>
#include <vstream.h>
#include <msg_vstream.h>
#include <readlline.h>
#include <stringops.h>
#include <split_at.h>
#include <vstring_vstream.h>
#include <set_eugid.h>
#include <warn_stat.h>
#include <clean_env.h>
#include <dict_db.h>

/* Global library. */

#include <tok822.h>
#include <mail_conf.h>
#include <mail_dict.h>
#include <mail_params.h>
#include <mail_version.h>
#include <mail_task.h>
#include <dict_proxy.h>
#include <mail_parm_split.h>
#include <maillog_client.h>

/* Application-specific. */

#define STR	vstring_str
#define LEN	VSTRING_LEN

#define POSTALIAS_FLAG_AS_OWNER	(1<<0)	/* open dest as owner of source */
#define POSTALIAS_FLAG_SAVE_PERM	(1<<1)	/* copy access permission
						 * from source */

/* postalias - create or update alias database */

static void postalias(char *map_type, char *path_name, int postalias_flags,
		              int open_flags, int dict_flags)
{
    VSTREAM *NOCLOBBER source_fp;
    VSTRING *line_buffer;
    MKMAP  *mkmap;
    int     lineno;
    int     last_line;
    VSTRING *key_buffer;
    VSTRING *value_buffer;
    TOK822 *tok_list;
    TOK822 *key_list;
    TOK822 *colon;
    TOK822 *value_list;
    struct stat st;
    mode_t  saved_mask;

    /*
     * Initialize.
     */
    line_buffer = vstring_alloc(100);
    key_buffer = vstring_alloc(100);
    value_buffer = vstring_alloc(100);
    if ((open_flags & O_TRUNC) == 0) {
	/* Incremental mode. */
	source_fp = VSTREAM_IN;
	vstream_control(source_fp, CA_VSTREAM_CTL_PATH("stdin"), CA_VSTREAM_CTL_END);
    } else {
	/* Create database. */
	if (strcmp(map_type, DICT_TYPE_PROXY) == 0)
	    msg_fatal("can't create maps via the proxy service");
	dict_flags |= DICT_FLAG_BULK_UPDATE;
	if ((source_fp = vstream_fopen(path_name, O_RDONLY, 0)) == 0)
	    msg_fatal("open %s: %m", path_name);
    }
    if (fstat(vstream_fileno(source_fp), &st) < 0)
	msg_fatal("fstat %s: %m", path_name);

    /*
     * Turn off group/other read permissions as indicated in the source file.
     */
    if ((postalias_flags & POSTALIAS_FLAG_SAVE_PERM) && S_ISREG(st.st_mode))
	saved_mask = umask(022 | (~st.st_mode & 077));

    /*
     * If running as root, run as the owner of the source file, so that the
     * result shows proper ownership, and so that a bug in postalias does not
     * allow privilege escalation.
     */
    if ((postalias_flags & POSTALIAS_FLAG_AS_OWNER) && getuid() == 0
	&& (st.st_uid != geteuid() || st.st_gid != getegid()))
	set_eugid(st.st_uid, st.st_gid);

    /*
     * Override the default per-table cache size for DB map (re)builds. We
     * can't do this in the mkmap* functions because those don't have access
     * to Postfix parameter settings.
     * 
     * db_cache_size" is defined in util/dict_open.c and defaults to 128kB,
     * which works well for the lookup code.
     * 
     * We use a larger per-table cache when building ".db" files. For "hash"
     * files performance degrades rapidly unless the memory pool is O(file
     * size).
     * 
     * For "btree" files performance is good with sorted input even for small
     * memory pools, but with random input degrades rapidly unless the memory
     * pool is O(file size).
     */
    dict_db_cache_size = var_db_create_buf;

    /*
     * Open the database, create it when it does not exist, truncate it when
     * it does exist, and lock out any spectators.
     */
    mkmap = mkmap_open(map_type, path_name, open_flags, dict_flags);

    /*
     * And restore the umask, in case it matters.
     */
    if ((postalias_flags & POSTALIAS_FLAG_SAVE_PERM) && S_ISREG(st.st_mode))
	umask(saved_mask);

    /*
     * Trap "exceptions" so that we can restart a bulk-mode update after a
     * recoverable error.
     */
    for (;;) {
	if (dict_isjmp(mkmap->dict) != 0
	    && dict_setjmp(mkmap->dict) != 0
	    && vstream_fseek(source_fp, SEEK_SET, 0) < 0)
	    msg_fatal("seek %s: %m", VSTREAM_PATH(source_fp));

	/*
	 * Add records to the database.
	 */
	last_line = 0;
	while (readllines(line_buffer, source_fp, &last_line, &lineno)) {

	    /*
	     * First some UTF-8 checks sans casefolding.
	     */
	    if ((mkmap->dict->flags & DICT_FLAG_UTF8_ACTIVE)
		&& !allascii(STR(line_buffer))
		&& !valid_utf8_stringz(STR(line_buffer))) {
		msg_warn("%s, line %d: non-UTF-8 input \"%s\""
			 " -- ignoring this line",
			 VSTREAM_PATH(source_fp), lineno, STR(line_buffer));
		continue;
	    }

	    /*
	     * Tokenize the input, so that we do the right thing when a
	     * quoted localpart contains special characters such as "@", ":"
	     * and so on.
	     */
	    if ((tok_list = tok822_scan(STR(line_buffer), (TOK822 **) 0)) == 0)
		continue;

	    /*
	     * Enforce the key:value format. Disallow missing keys,
	     * multi-address keys, or missing values. In order to specify an
	     * empty string or value, enclose it in double quotes.
	     */
	    if ((colon = tok822_find_type(tok_list, ':')) == 0
		|| colon->prev == 0 || colon->next == 0
		|| tok822_rfind_type(colon, ',')) {
		msg_warn("%s, line %d: need name:value pair",
			 VSTREAM_PATH(source_fp), lineno);
		tok822_free_tree(tok_list);
		continue;
	    }

	    /*
	     * Key must be local. XXX We should use the Postfix rewriting and
	     * resolving services to handle all address forms correctly.
	     * However, we can't count on the mail system being up when the
	     * alias database is being built, so we're guessing a bit.
	     */
	    if (tok822_rfind_type(colon, '@') || tok822_rfind_type(colon, '%')) {
		msg_warn("%s, line %d: name must be local and have no domain",
			 VSTREAM_PATH(source_fp), lineno);
		tok822_free_tree(tok_list);
		continue;
	    }

	    /*
	     * Split the input into key and value parts, and convert from
	     * token representation back to string representation. Convert
	     * the key to internal (unquoted) form, because the resolver
	     * produces addresses in internal form. Convert the value to
	     * external (quoted) form, because it will have to be re-parsed
	     * upon lookup. Discard the token representation when done.
	     */
	    key_list = tok_list;
	    tok_list = 0;
	    value_list = tok822_cut_after(colon);
	    tok822_unlink(colon);
	    tok822_free(colon);

	    tok822_internalize(key_buffer, key_list, TOK822_STR_DEFL);
	    tok822_free_tree(key_list);

	    tok822_externalize(value_buffer, value_list, TOK822_STR_DEFL);
	    tok822_free_tree(value_list);

	    /*
	     * Store the value under a case-insensitive key.
	     */
	    mkmap_append(mkmap, STR(key_buffer), STR(value_buffer));
	    if (mkmap->dict->error)
		msg_fatal("table %s:%s: write error: %m",
			  mkmap->dict->type, mkmap->dict->name);
	}
	break;
    }

    /*
     * Update or append sendmail and NIS signatures.
     */
    if ((open_flags & O_TRUNC) == 0)
	mkmap->dict->flags |= DICT_FLAG_DUP_REPLACE;

    /*
     * Sendmail compatibility: add the @:@ signature to indicate that the
     * database is complete. This might be needed by NIS clients running
     * sendmail.
     */
    mkmap_append(mkmap, "@", "@");
    if (mkmap->dict->error)
	msg_fatal("table %s:%s: write error: %m",
		  mkmap->dict->type, mkmap->dict->name);

    /*
     * NIS compatibility: add time and master info. Unlike other information,
     * this information MUST be written without a trailing null appended to
     * key or value.
     */
    mkmap->dict->flags &= ~DICT_FLAG_TRY1NULL;
    mkmap->dict->flags |= DICT_FLAG_TRY0NULL;
    vstring_sprintf(value_buffer, "%010ld", (long) time((time_t *) 0));
#if (defined(HAS_NIS) || defined(HAS_NISPLUS))
    mkmap->dict->flags &= ~DICT_FLAG_FOLD_FIX;
    mkmap_append(mkmap, "YP_LAST_MODIFIED", STR(value_buffer));
    mkmap_append(mkmap, "YP_MASTER_NAME", var_myhostname);
#endif

    /*
     * Close the alias database, and release the lock.
     */
    mkmap_close(mkmap);

    /*
     * Cleanup. We're about to terminate, but it is a good sanity check.
     */
    vstring_free(value_buffer);
    vstring_free(key_buffer);
    vstring_free(line_buffer);
    if (source_fp != VSTREAM_IN)
	vstream_fclose(source_fp);
}

/* postalias_queries - apply multiple requests from stdin */

static int postalias_queries(VSTREAM *in, char **maps, const int map_count,
			             const int dict_flags)
{
    int     found = 0;
    VSTRING *keybuf = vstring_alloc(100);
    DICT  **dicts;
    const char *map_name;
    const char *value;
    int     n;

    /*
     * Sanity check.
     */
    if (map_count <= 0)
	msg_panic("postalias_queries: bad map count");

    /*
     * Prepare to open maps lazily.
     */
    dicts = (DICT **) mymalloc(sizeof(*dicts) * map_count);
    for (n = 0; n < map_count; n++)
	dicts[n] = 0;

    /*
     * Perform all queries. Open maps on the fly, to avoid opening
     * unnecessary maps.
     */
    while (vstring_get_nonl(keybuf, in) != VSTREAM_EOF) {
	for (n = 0; n < map_count; n++) {
	    if (dicts[n] == 0)
		dicts[n] = ((map_name = split_at(maps[n], ':')) != 0 ?
		       dict_open3(maps[n], map_name, O_RDONLY, dict_flags) :
		    dict_open3(var_db_type, maps[n], O_RDONLY, dict_flags));
	    if ((value = dict_get(dicts[n], STR(keybuf))) != 0) {
		if (*value == 0) {
		    msg_warn("table %s:%s: key %s: empty string result is not allowed",
			     dicts[n]->type, dicts[n]->name, STR(keybuf));
		    msg_warn("table %s:%s should return NO RESULT in case of NOT FOUND",
			     dicts[n]->type, dicts[n]->name);
		}
		vstream_printf("%s:	%s\n", STR(keybuf), value);
		found = 1;
		break;
	    }
	    if (dicts[n]->error)
		msg_fatal("table %s:%s: query error: %m",
			  dicts[n]->type, dicts[n]->name);
	}
    }
    if (found)
	vstream_fflush(VSTREAM_OUT);

    /*
     * Cleanup.
     */
    for (n = 0; n < map_count; n++)
	if (dicts[n])
	    dict_close(dicts[n]);
    myfree((void *) dicts);
    vstring_free(keybuf);

    return (found);
}

/* postalias_query - query a map and print the result to stdout */

static int postalias_query(const char *map_type, const char *map_name,
			           const char *key, int dict_flags)
{
    DICT   *dict;
    const char *value;

    dict = dict_open3(map_type, map_name, O_RDONLY, dict_flags);
    if ((value = dict_get(dict, key)) != 0) {
	if (*value == 0) {
	    msg_warn("table %s:%s: key %s: empty string result is not allowed",
		     map_type, map_name, key);
	    msg_warn("table %s:%s should return NO RESULT in case of NOT FOUND",
		     map_type, map_name);
	}
	vstream_printf("%s\n", value);
    }
    if (dict->error)
	msg_fatal("table %s:%s: query error: %m", dict->type, dict->name);
    vstream_fflush(VSTREAM_OUT);
    dict_close(dict);
    return (value != 0);
}

/* postalias_deletes - apply multiple requests from stdin */

static int postalias_deletes(VSTREAM *in, char **maps, const int map_count,
			             int dict_flags)
{
    int     found = 0;
    VSTRING *keybuf = vstring_alloc(100);
    DICT  **dicts;
    const char *map_name;
    int     n;
    int     open_flags;

    /*
     * Sanity check.
     */
    if (map_count <= 0)
	msg_panic("postalias_deletes: bad map count");

    /*
     * Open maps ahead of time.
     */
    dicts = (DICT **) mymalloc(sizeof(*dicts) * map_count);
    for (n = 0; n < map_count; n++) {
	map_name = split_at(maps[n], ':');
	if (map_name && strcmp(maps[n], DICT_TYPE_PROXY) == 0)
	    open_flags = O_RDWR | O_CREAT;	/* XXX */
	else
	    open_flags = O_RDWR;
	dicts[n] = (map_name != 0 ?
		    dict_open3(maps[n], map_name, open_flags, dict_flags) :
		  dict_open3(var_db_type, maps[n], open_flags, dict_flags));
    }

    /*
     * Perform all requests.
     */
    while (vstring_get_nonl(keybuf, in) != VSTREAM_EOF) {
	for (n = 0; n < map_count; n++) {
	    found |= (dict_del(dicts[n], STR(keybuf)) == 0);
	    if (dicts[n]->error)
		msg_fatal("table %s:%s: delete error: %m",
			  dicts[n]->type, dicts[n]->name);
	}
    }

    /*
     * Cleanup.
     */
    for (n = 0; n < map_count; n++)
	if (dicts[n])
	    dict_close(dicts[n]);
    myfree((void *) dicts);
    vstring_free(keybuf);

    return (found);
}

/* postalias_delete - delete a key value pair from a map */

static int postalias_delete(const char *map_type, const char *map_name,
			            const char *key, int dict_flags)
{
    DICT   *dict;
    int     status;
    int     open_flags;

    if (strcmp(map_type, DICT_TYPE_PROXY) == 0)
	open_flags = O_RDWR | O_CREAT;		/* XXX */
    else
	open_flags = O_RDWR;
    dict = dict_open3(map_type, map_name, open_flags, dict_flags);
    status = dict_del(dict, key);
    if (dict->error)
	msg_fatal("table %s:%s: delete error: %m", dict->type, dict->name);
    dict_close(dict);
    return (status == 0);
}

/* postalias_seq - print all map entries to stdout */

static void postalias_seq(const char *map_type, const char *map_name,
			          int dict_flags)
{
    DICT   *dict;
    const char *key;
    const char *value;
    int     func;

    if (strcmp(map_type, DICT_TYPE_PROXY) == 0)
	msg_fatal("can't sequence maps via the proxy service");
    dict = dict_open3(map_type, map_name, O_RDONLY, dict_flags);
    for (func = DICT_SEQ_FUN_FIRST; /* void */ ; func = DICT_SEQ_FUN_NEXT) {
	if (dict_seq(dict, func, &key, &value) != 0)
	    break;
	if (*key == 0) {
	    msg_warn("table %s:%s: empty lookup key value is not allowed",
		     map_type, map_name);
	} else if (*value == 0) {
	    msg_warn("table %s:%s: key %s: empty string result is not allowed",
		     map_type, map_name, key);
	    msg_warn("table %s:%s should return NO RESULT in case of NOT FOUND",
		     map_type, map_name);
	}
	vstream_printf("%s:	%s\n", key, value);
    }
    if (dict->error)
	msg_fatal("table %s:%s: sequence error: %m", dict->type, dict->name);
    vstream_fflush(VSTREAM_OUT);
    dict_close(dict);
}

/* usage - explain */

static NORETURN usage(char *myname)
{
    msg_fatal("usage: %s [-Nfinoprsuvw] [-c config_dir] [-d key] [-q key] [map_type:]file...",
	      myname);
}

MAIL_VERSION_STAMP_DECLARE;

int     main(int argc, char **argv)
{
    char   *path_name;
    int     ch;
    int     fd;
    char   *slash;
    struct stat st;
    int     postalias_flags = POSTALIAS_FLAG_AS_OWNER | POSTALIAS_FLAG_SAVE_PERM;
    int     open_flags = O_RDWR | O_CREAT | O_TRUNC;
    int     dict_flags = (DICT_FLAG_DUP_WARN | DICT_FLAG_FOLD_FIX
			  | DICT_FLAG_UTF8_REQUEST);
    char   *query = 0;
    char   *delkey = 0;
    int     sequence = 0;
    int     found;
    ARGV   *import_env;

    /*
     * Fingerprint executables and core dumps.
     */
    MAIL_VERSION_STAMP_ALLOCATE;

    /*
     * Be consistent with file permissions.
     */
    umask(022);

    /*
     * To minimize confusion, make sure that the standard file descriptors
     * are open before opening anything else. XXX Work around for 44BSD where
     * fstat can return EBADF on an open file descriptor.
     */
    for (fd = 0; fd < 3; fd++)
	if (fstat(fd, &st) == -1
	    && (close(fd), open("/dev/null", O_RDWR, 0)) != fd)
	    msg_fatal("open /dev/null: %m");

    /*
     * Process environment options as early as we can. We are not set-uid,
     * and we are supposed to be running in a controlled environment.
     */
    if (getenv(CONF_ENV_VERB))
	msg_verbose = 1;

    /*
     * Initialize. Set up logging. Read the global configuration file after
     * parsing command-line arguments.
     */
    if ((slash = strrchr(argv[0], '/')) != 0 && slash[1])
	argv[0] = slash + 1;
    msg_vstream_init(argv[0], VSTREAM_ERR);
    maillog_client_init(mail_task(argv[0]), MAILLOG_CLIENT_FLAG_NONE);

    /*
     * Check the Postfix library version as soon as we enable logging.
     */
    MAIL_VERSION_CHECK;

    /*
     * Parse JCL.
     */
    while ((ch = GETOPT(argc, argv, "Nc:d:finopq:rsuvw")) > 0) {
	switch (ch) {
	default:
	    usage(argv[0]);
	    break;
	case 'N':
	    dict_flags |= DICT_FLAG_TRY1NULL;
	    dict_flags &= ~DICT_FLAG_TRY0NULL;
	    break;
	case 'c':
	    if (setenv(CONF_ENV_PATH, optarg, 1) < 0)
		msg_fatal("out of memory");
	    break;
	case 'd':
	    if (sequence || query || delkey)
		msg_fatal("specify only one of -s -q or -d");
	    delkey = optarg;
	    break;
	case 'f':
	    dict_flags &= ~DICT_FLAG_FOLD_FIX;
	    break;
	case 'i':
	    open_flags &= ~O_TRUNC;
	    break;
	case 'n':
	    dict_flags |= DICT_FLAG_TRY0NULL;
	    dict_flags &= ~DICT_FLAG_TRY1NULL;
	    break;
	case 'o':
	    postalias_flags &= ~POSTALIAS_FLAG_AS_OWNER;
	    break;
	case 'p':
	    postalias_flags &= ~POSTALIAS_FLAG_SAVE_PERM;
	    break;
	case 'q':
	    if (sequence || query || delkey)
		msg_fatal("specify only one of -s -q or -d");
	    query = optarg;
	    break;
	case 'r':
	    dict_flags &= ~(DICT_FLAG_DUP_WARN | DICT_FLAG_DUP_IGNORE);
	    dict_flags |= DICT_FLAG_DUP_REPLACE;
	    break;
	case 's':
	    if (query || delkey)
		msg_fatal("specify only one of -s or -q or -d");
	    sequence = 1;
	    break;
	case 'u':
	    dict_flags &= ~DICT_FLAG_UTF8_REQUEST;
	    break;
	case 'v':
	    msg_verbose++;
	    break;
	case 'w':
	    dict_flags &= ~(DICT_FLAG_DUP_WARN | DICT_FLAG_DUP_REPLACE);
	    dict_flags |= DICT_FLAG_DUP_IGNORE;
	    break;
	}
    }
    mail_conf_read();
    /* Enforce consistent operation of different Postfix parts. */
    import_env = mail_parm_split(VAR_IMPORT_ENVIRON, var_import_environ);
    update_env(import_env->argv);
    argv_free(import_env);
    /* Re-evaluate mail_task() after reading main.cf. */
    maillog_client_init(mail_task(argv[0]), MAILLOG_CLIENT_FLAG_NONE);
    mail_dict_init();

    /*
     * Use the map type specified by the user, or fall back to a default
     * database type.
     */
    if (delkey) {				/* remove entry */
	if (optind + 1 > argc)
	    usage(argv[0]);
	if (strcmp(delkey, "-") == 0)
	    exit(postalias_deletes(VSTREAM_IN, argv + optind, argc - optind,
				   dict_flags | DICT_FLAG_LOCK) == 0);
	found = 0;
	while (optind < argc) {
	    if ((path_name = split_at(argv[optind], ':')) != 0) {
		found |= postalias_delete(argv[optind], path_name, delkey,
					  dict_flags | DICT_FLAG_LOCK);
	    } else {
		found |= postalias_delete(var_db_type, argv[optind], delkey,
					  dict_flags | DICT_FLAG_LOCK);
	    }
	    optind++;
	}
	exit(found ? 0 : 1);
    } else if (query) {				/* query map(s) */
	if (optind + 1 > argc)
	    usage(argv[0]);
	if (strcmp(query, "-") == 0)
	    exit(postalias_queries(VSTREAM_IN, argv + optind, argc - optind,
				   dict_flags | DICT_FLAG_LOCK) == 0);
	while (optind < argc) {
	    if ((path_name = split_at(argv[optind], ':')) != 0) {
		found = postalias_query(argv[optind], path_name, query,
					dict_flags | DICT_FLAG_LOCK);
	    } else {
		found = postalias_query(var_db_type, argv[optind], query,
					dict_flags | DICT_FLAG_LOCK);
	    }
	    if (found)
		exit(0);
	    optind++;
	}
	exit(1);
    } else if (sequence) {
	while (optind < argc) {
	    if ((path_name = split_at(argv[optind], ':')) != 0) {
		postalias_seq(argv[optind], path_name,
			      dict_flags | DICT_FLAG_LOCK);
	    } else {
		postalias_seq(var_db_type, argv[optind],
			      dict_flags | DICT_FLAG_LOCK);
	    }
	    exit(0);
	}
	exit(1);
    } else {					/* create/update map(s) */
	if (optind + 1 > argc)
	    usage(argv[0]);
	while (optind < argc) {
	    if ((path_name = split_at(argv[optind], ':')) != 0) {
		postalias(argv[optind], path_name, postalias_flags,
			  open_flags, dict_flags);
	    } else {
		postalias(var_db_type, argv[optind], postalias_flags,
			  open_flags, dict_flags);
	    }
	    optind++;
	}
	exit(0);
    }
}
