- modified courier-imap-authmysql.patch

[packages/courier-imap.git] / courier-imap-authmysql.patch

diff -ur courier-imap-1.3.12.orig/authlib/authmysqllib.c courier-imap-1.3.12/authlib/authmysqllib.c
--- courier-imap-1.3.12.orig/authlib/authmysqllib.c	Mon Aug  6 05:12:39 2001
+++ courier-imap-1.3.12/authlib/authmysqllib.c	Wed Dec 26 05:46:05 2001
@@ -3,7 +3,6 @@
 ** distribution information.
 */
 
-
 #include	<stdio.h>
 #include	<stdlib.h>
 #include	<string.h>
@@ -20,6 +19,17 @@
 
 static const char rcsid[]="$Id$";
 
+struct var_data {			
+	const char *name;
+	const char *value;
+	const size_t size;
+	size_t value_length;
+	} ;				/* siefca@pld.org.pl */
+
+typedef size_t (*parsefunc)(const char *, size_t, struct var_data *);
+parsefunc ParsePlugin_build = NULL;	/* siefca@pld.org.pl */
+
+
 static const char *read_env(const char *env)
 {
 static char *mysqlauth=0;
@@ -51,7 +61,13 @@
 
 		for (i=0; i<mysqlauth_size; i++)
 			if (mysqlauth[i] == '\n')
-				mysqlauth[i]=0;
+			{	/* siefca@pld.org.pl */
+				if (!i || mysqlauth[i-1] != '\\')
+					mysqlauth[i]	='\0';
+				else
+					mysqlauth[i]	=
+					mysqlauth[i-1]	= ' ';
+			}
 		fclose(f);
 	}
 
@@ -199,17 +215,356 @@
 		strcat(strcpy(p, "@"), defdomain);
 }
 
+/* siefca@pld.org.pl */
+static const char *get_var_value (const char *begin, size_t len,
+  		  	          struct var_data *vd)
+{
+struct var_data *vdp;
+
+	for (vdp=vd; vdp->name; vdp++)
+		if (vdp->size == len+1 &&
+		    !strncmp(begin, vdp->name, len))
+		    	{
+				if (vdp->value)
+					return (vdp->value);
+				else
+					return "";
+			}
+	
+	fprintf (stderr, "authmysql: unknown substitution variable "
+			 "$(%.*s)\n", len, begin);
+	
+	return NULL;
+}
+
+/* siefca@pld.org.pl */
+static size_t parse_core (const char *source, struct var_data *vd,
+			  parsefunc outfn, char *result)
+{
+size_t	counter	= 0,
+	s	= 0,
+	v_size	= 0,
+	t_size	= 0;
+const char	*p, *q, *e,
+		*v_begin, *v_end,
+		*t_begin, *t_end,
+		*var_value;
+
+	if (!source)
+		source = "";
+	if (result)
+		*result = '\0';
+
+	q = source;
+	while ( (p=strstr(q, "$(")) )
+	{
+		e = strchr (p, ')');
+		if (!e)
+		{
+			fprintf (stderr, "authmysql: syntax error in "
+					 "substitution variable "
+					 "- no closing bracket!\n"
+					 "authmysql: bad variable begins "
+					 "with: %.*s...\n", 20, p);
+			return -1;
+		}
+		
+		/*
+		 **
+		 **	     __________sometext$(variable_name)_________
+		 **	 	       |      |  |	     |	
+		 **	        t_begin' t_end'  `v_begin    `v_end
+		 **
+		  */
+
+		v_begin	= p+2;		  /* variable field ptr		   */
+		v_end	= e-1;		  /* variable field last character */
+		v_size	= v_end-v_begin+1;/* variable field length	   */
+		
+		t_begin	= q;		  /* text field ptr		   */
+		t_end	= p-1;		  /* text field last character	   */
+		t_size	= t_end-t_begin+1;/* text field length		   */
+
+		if (result)		/* function building mode */
+		{
+			 var_value = get_var_value (v_begin, v_size, vd);
+			 if (!var_value) return -1;
+			 strncat (result, t_begin, t_size);
+			 strcat (result, var_value);
+		}
+		else			/* function counting mode */
+		{			
+			s = outfn (v_begin, v_size, vd);
+			if (s == -1) return -1;
+			counter += s;
+		}
+		q = e + 1;
+	}
+
+	if (result)
+		strcat(result, q);
+		
+	return counter;
+}
+
+/* siefca@pld.org.pl */
+size_t ParsePlugin_variable_len (const char *begin, size_t len,
+			         struct var_data *vd)
+{
+	return (len + 3);
+}
+
+/* siefca@pld.org.pl */
+size_t ParsePlugin_validate (const char *begin, size_t len,
+			     struct var_data *vd)
+{
+struct var_data *vdp;
+
+	if (!len)
+	{
+		fprintf (stderr, "authmysql: unknown empty substitution "
+				 "variable - aborting\n");
+		return -1;
+	}
+
+	if (!begin || !vd) /* should never happend */
+	{
+		fprintf (stderr, "authmysql: critical error while "
+				  "parsing substitution variable\n");
+		return -1;
+	}
+
+	if (len > 32)
+	{
+		fprintf (stderr, "authmysql: variable name too long "
+				 "while parsing substitution\n"
+				 "authmysql: name begins with "
+				 "$(%.*s...\n", 32, begin);
+		return -1;
+	}
+	
+	for (vdp=vd; vdp->name; vdp++)
+		if (vdp->size == len+1 &&
+		    !strncmp(begin, vdp->name, len))
+			return 0;
+	
+	fprintf (stderr, "authmysql: unknown substitution variable "
+			 "$(%.*s)\n", len, begin);
+	return -1;
+}
+
+/* siefca@pld.org.pl */
+size_t ParsePlugin_value_len   (const char *begin, size_t len,
+			        struct var_data *vd)
+{
+struct var_data *vdp;
+
+	for (vdp=vd; vdp->name; vdp++)
+		if (vdp->size == len+1 &&
+		    !strncmp(begin, vdp->name, len))
+		{
+			if (!vdp->value)	/* should never happend */
+				return 0;
+			if (!vdp->value_length)		/* length cache */
+				vdp->value_length = strlen (vdp->value);
+			return (vdp->value_length);
+		}
+
+	fprintf (stderr, "authmysql: missing variable while calculating values "
+			 "for substitution!\n");
+			 
+	return -1;
+}
+
+/* siefca@pld.org.pl */
+static char *parse_string (const char *source, struct var_data *vd)
+{
+char	*output_buf;
+size_t	buf_size,
+	variables_size,
+	values_size;
+
+	if (source == NULL || *source == '\0' || 
+	    vd == NULL     || vd[0].name == NULL)
+	{
+		fprintf (stderr, "authmysql: source clause is empty "
+				 "- this is critical error\n");
+		return NULL;
+	}
+
+	/* phase 1 - check for bad variables */
+	if ((parse_core (source, vd, ParsePlugin_validate, NULL)) != 0)
+		return NULL;
+
+	/* phase 2 - calculate output buffer space */
+	values_size    = parse_core (source, vd, ParsePlugin_value_len, NULL);
+	variables_size = parse_core (source, vd, ParsePlugin_variable_len, NULL);
+	if (variables_size == -1 || values_size == -1)	return NULL;
+	buf_size = 2 + (strlen(source)) + values_size - variables_size;
+
+	/* phase 3 - allocate memory */
+	output_buf = malloc (buf_size);
+	if (!output_buf)
+	{
+		perror ("malloc");
+		return NULL;
+	}
+
+	/* phase 4 - build the output string */
+	if ((parse_core (source, vd, ParsePlugin_build, output_buf)) != 0)
+	{
+		free (output_buf);
+		return NULL;
+	}
+	
+	return output_buf;
+}	
+
+/* siefca@pld.org.pl */
+static const char *get_localpart (const char *username)
+{
+char *p;
+static char localpart_buf[130];
+	
+	if (!username || *username == '\0') return NULL;
+	p = strchr(username,'@');
+	if (p)
+	{
+		if (p-username > 128) return NULL;
+		strncpy (localpart_buf, username, p-username);
+	}
+	else
+	{
+		if ((strlen(username)) > 128) return NULL;
+		strcpy (localpart_buf, username);
+	}
+
+	for (p = localpart_buf; *p; p++)
+		if (*p == '\"' || *p == '\\' ||
+		    *p == '\'' || (int)(unsigned char)*p < ' ')
+			*p=' ';
+
+	return localpart_buf;
+}
+
+/* siefca@pld.org.pl */
+static const char *get_domain (const char *username, const char *defdomain)
+{
+static char	domain_buf[260];
+char		*p, *q;
+	
+	if (!username || *username == '\0') return NULL;
+	p = strchr(username,'@');
+	
+	if (p && *(p+1))
+	    {
+		p++;
+		if ((strlen(p)) > 256) return NULL;
+		for (q=domain_buf; *p; p++, q++)
+		   if (*p == '\"' || *p == '\\' ||
+		       *p == '\'' || (int)(unsigned char)*p < ' ')
+			*p=' ';
+		    else
+			*q=*p;
+		*q='\0';
+		return domain_buf;
+	    }
+	if (defdomain && *defdomain) return defdomain;
+	
+	return NULL;	
+}
+
+/* siefca@pld.org.pl */
+
+static const char *validate_password (const char *password)
+{
+static char	pass_buf[260];
+const char	*p;
+char		*q;
+	
+	if (!password || *password == '\0') return NULL;
+	
+	if ((strlen(password)) > 256) return NULL;
+	strcpy (pass_buf, password);
+	for (p=password,q=pass_buf; *p != '\0'; p++, q++)
+	{
+		if (*p == '\"' || *p == '\\' || *p == '\'')
+			*q++ = '\\';
+		*q = *p;	
+	}
+	
+	*q = '\0';
+
+	return pass_buf;
+}
+
+
+/* siefca@pld.org.pl */
+static char *parse_select_clause (const char *clause, const char *username,
+				  const char *defdomain)
+{
+static struct var_data vd[]={
+	    {"local_part",	NULL,	sizeof("local_part"),	0},
+	    {"domain",		NULL,	sizeof("domain"),	0},
+	    {NULL,		NULL,	0,			0}};
+
+	if (clause == NULL || *clause == '\0' ||
+	    !username || *username == '\0') return NULL;
+	
+	vd[0].value	= get_localpart (username);
+	vd[1].value	= get_domain (username, defdomain);
+	if (!vd[0].value || !vd[1].value) return NULL;
+	
+	return (parse_string (clause, vd));
+}
+
+/* siefca@pld.org.pl */
+static char *parse_chpass_clause (const char *clause, const char *username,
+				  const char *defdomain, const char *newpass,
+				  const char *newpass_crypt)
+{
+static struct var_data vd[]={
+	    {"local_part",	NULL,	sizeof("local_part"),		0},
+	    {"domain",		NULL,	sizeof("domain"),		0},
+	    {"newpass",		NULL, 	sizeof("newpass"),		0},
+	    {"newpass_crypt",	NULL,	sizeof("newpass_crypt"),	0},
+	    {NULL,		NULL,	0,				0}};
+
+	if (clause == NULL || *clause == '\0'		||
+	    !username || *username == '\0'		||
+	    !newpass || *newpass == '\0'		||
+	    !newpass_crypt || *newpass_crypt == '\0') return NULL;
+
+	vd[0].value	= get_localpart (username);
+	vd[1].value	= get_domain (username, defdomain);
+	vd[2].value	= validate_password (newpass);
+	vd[3].value	= validate_password (newpass_crypt);
+	
+	if (!vd[0].value || !vd[1].value ||
+	    !vd[2].value || !vd[3].value)	return NULL;
+
+	return (parse_string (clause, vd));
+}
+
 struct authmysqluserinfo *auth_mysql_getuserinfo(const char *username)
 {
-const char *user_table;
-const char *defdomain;
+const char *user_table	=NULL;
+const char *defdomain	=NULL;
 char	*querybuf, *p;
 MYSQL_ROW	row;
 MYSQL_RES	*result;
 
-const char *crypt_field, *clear_field, *maildir_field, *home_field,
-	*name_field,
-	*login_field, *uid_field, *gid_field, *quota_field, *where_clause;
+const char  *crypt_field	=NULL, 
+	    *clear_field	=NULL,
+	    *maildir_field	=NULL,
+	    *home_field		=NULL,
+	    *name_field		=NULL,
+	    *login_field	=NULL,
+	    *uid_field		=NULL,
+	    *gid_field		=NULL,
+	    *quota_field	=NULL,
+	    *where_clause	=NULL,
+	    *select_clause	=NULL; /* siefca@pld.org.pl */
 
 static const char query[]=
 	"SELECT %s, %s, %s, %s, %s, %s, %s, %s, %s FROM %s WHERE %s = \"";
@@ -232,79 +587,95 @@
 		free(ui.fullname);
 	memset(&ui, 0, sizeof(ui));
 
-	user_table=read_env("MYSQL_USER_TABLE");
-	defdomain=read_env("DEFAULT_DOMAIN");
-
-	if (!user_table)
+	select_clause=read_env("MYSQL_SELECT_CLAUSE");
+	defdomain=read_env("DEFAULT_DOMAIN");	
+	
+	if (!select_clause) /* siefca@pld.org.pl */
 	{
-		fprintf(stderr, "authmysql: MYSQL_USER_TABLE not set in "
-			AUTHMYSQLRC ".\n");
-		return (0);
-	}
+		user_table=read_env("MYSQL_USER_TABLE");
 
-	crypt_field=read_env("MYSQL_CRYPT_PWFIELD");
-	clear_field=read_env("MYSQL_CLEAR_PWFIELD");
-	name_field=read_env("MYSQL_NAME_FIELD");
+		if (!user_table)
+		{
+			fprintf(stderr, "authmysql: MYSQL_USER_TABLE not set in "
+				AUTHMYSQLRC ".\n");
+			return (0);
+		}
 
-	if (!crypt_field && !clear_field)
-	{
-		fprintf(stderr,
-			"authmysql: MYSQL_CRYPT_PWFIELD and "
-			"MYSQL_CLEAR_PWFIELD not set in " AUTHMYSQLRC ".\n");
-		return (0);
-	}
-	if (!crypt_field) crypt_field="\"\"";
-	if (!clear_field) clear_field="\"\"";
-	if (!name_field) name_field="\"\"";
+		crypt_field=read_env("MYSQL_CRYPT_PWFIELD");
+		clear_field=read_env("MYSQL_CLEAR_PWFIELD");
+		name_field=read_env("MYSQL_NAME_FIELD");
 
-	uid_field = read_env("MYSQL_UID_FIELD");
-	if (!uid_field) uid_field = "uid";
+		if (!crypt_field && !clear_field)
+		{
+			fprintf(stderr,
+				"authmysql: MYSQL_CRYPT_PWFIELD and "
+				"MYSQL_CLEAR_PWFIELD not set in " AUTHMYSQLRC ".\n");
+			return (0);
+		}
+		if (!crypt_field) crypt_field="\"\"";
+		if (!clear_field) clear_field="\"\"";
+		if (!name_field) name_field="\"\"";
 
-	gid_field = read_env("MYSQL_GID_FIELD");
-	if (!gid_field) gid_field = "gid";
+		uid_field = read_env("MYSQL_UID_FIELD");
+		if (!uid_field) uid_field = "uid";
 
-	login_field = read_env("MYSQL_LOGIN_FIELD");
-	if (!login_field) login_field = "id";
+		gid_field = read_env("MYSQL_GID_FIELD");
+		if (!gid_field) gid_field = "gid";
 
-	home_field = read_env("MYSQL_HOME_FIELD");
-	if (!home_field) home_field = "home";
+		login_field = read_env("MYSQL_LOGIN_FIELD");
+		if (!login_field) login_field = "id";
 
-	maildir_field=read_env("MYSQL_MAILDIR_FIELD");
-	if (!maildir_field) maildir_field="\"\"";
+		home_field = read_env("MYSQL_HOME_FIELD");
+		if (!home_field) home_field = "home";
 
-	quota_field=read_env("MYSQL_QUOTA_FIELD");
-	if (!quota_field) quota_field="\"\""; 
+		maildir_field=read_env("MYSQL_MAILDIR_FIELD");
+		if (!maildir_field) maildir_field="\"\"";
 
-	where_clause=read_env("MYSQL_WHERE_CLAUSE");
-	if (!where_clause) where_clause = "";
+		quota_field=read_env("MYSQL_QUOTA_FIELD");
+		if (!quota_field) quota_field="\"\""; 
+
+		where_clause=read_env("MYSQL_WHERE_CLAUSE");
+		if (!where_clause) where_clause = "";
+	}
 	
 	if (!defdomain)	defdomain="";
 
-	querybuf=malloc(sizeof(query) + 100 + strlen(user_table) + strlen(defdomain)
-		+ strlen(crypt_field) + strlen(clear_field) + strlen(maildir_field)
-		+ strlen(uid_field) + strlen(gid_field) + 2 * strlen(login_field)
-		+ strlen(home_field) + strlen(quota_field) + strlen(where_clause)
-			+ strlen(name_field));
-	if (!querybuf)
+	if (!select_clause) /* siefca@pld.org.pl */
 	{
-		perror("malloc");
-		return (0);
-	}
+		querybuf=malloc(sizeof(query) + 100 + strlen(user_table) + strlen(defdomain)
+			+ strlen(crypt_field) + strlen(clear_field) + strlen(maildir_field)
+			+ strlen(uid_field) + strlen(gid_field) + 2 * strlen(login_field)
+			+ strlen(home_field) + strlen(quota_field) + strlen(where_clause)
+			+ strlen(name_field));
 
-	sprintf(querybuf, query, login_field, crypt_field, clear_field, 
-		uid_field, gid_field, home_field, maildir_field, quota_field,
-		name_field, user_table, login_field);
-	p=querybuf+strlen(querybuf);
+		if (!querybuf)
+		{
+			perror("malloc");
+			return (0);
+		}
+
+		sprintf(querybuf, query, login_field, crypt_field, clear_field, 
+			uid_field, gid_field, home_field, maildir_field, quota_field,
+			name_field, user_table, login_field);
+
+		p=querybuf+strlen(querybuf);
 
-	append_username(p, username, defdomain);
-	strcat(p, "\"");
+		append_username(p, username, defdomain);
+		strcat(p, "\"");
 	
-	if (strcmp(where_clause, "")) {
-		strcat(p, " AND (");
-		strcat(p, where_clause);
-		strcat(p, ")");
+		if (strcmp(where_clause, "")) {
+			strcat(p, " AND (");
+			strcat(p, where_clause);
+			strcat(p, ")");
+		}
 	}
-	
+	else
+	{
+		/* siefca@pld.org.pl */
+		querybuf=parse_select_clause (select_clause, username, defdomain);
+		if (!querybuf) return 0;
+	}
+
 	if (mysql_query (mysql, querybuf))
 	{
 		/* <o.blasnik@nextra.de> */
@@ -379,12 +750,13 @@
 	const char *comma;
 	int rc=0;
 
-	const char *clear_field;
-	const char *crypt_field;
-	const char *defdomain;
-	const char *where_clause;
-	const char *user_table;
-	const char *login_field;
+	const char  *clear_field	=NULL,
+		    *crypt_field	=NULL,
+		    *defdomain		=NULL,
+		    *where_clause	=NULL,
+		    *user_table		=NULL,
+		    *login_field	=NULL,
+		    *chpass_clause	=NULL; /* siefca@pld.org.pl */
 
 	if (!mysql)
 		return (-1);
@@ -412,21 +784,34 @@
 		++l;
 	}
 
-	login_field = read_env("MYSQL_LOGIN_FIELD");
-	if (!login_field) login_field = "id";
-	crypt_field=read_env("MYSQL_CRYPT_PWFIELD");
-	clear_field=read_env("MYSQL_CLEAR_PWFIELD");
+	/* siefca@pld.org.pl */
+	chpass_clause=read_env("MYSQL_CHPASS_CLAUSE");
 	defdomain=read_env("DEFAULT_DOMAIN");
-	where_clause=read_env("MYSQL_WHERE_CLAUSE");
 	user_table=read_env("MYSQL_USER_TABLE");
-
-	sql_buf=malloc(strlen(crypt_field ? crypt_field:"")
-		       + strlen(clear_field ? clear_field:"")
-		       + strlen(defdomain ? defdomain:"")
-		       + strlen(login_field) + l + strlen(newpass_crypt)
-		       + strlen(user_table)
-		       + strlen(where_clause ? where_clause:"")
-		       + 200);
+	if (!chpass_clause)
+	{
+		login_field = read_env("MYSQL_LOGIN_FIELD");
+		if (!login_field) login_field = "id";
+		crypt_field=read_env("MYSQL_CRYPT_PWFIELD");
+		clear_field=read_env("MYSQL_CLEAR_PWFIELD");
+		where_clause=read_env("MYSQL_WHERE_CLAUSE");
+		sql_buf=malloc(strlen(crypt_field ? crypt_field:"")
+				+ strlen(clear_field ? clear_field:"")
+				+ strlen(defdomain ? defdomain:"")
+				+ strlen(login_field) + l + strlen(newpass_crypt)
+				+ strlen(user_table)
+				+ strlen(where_clause ? where_clause:"")
+				+ 200);
+	}
+	else
+	{
+		sql_buf=parse_chpass_clause(chpass_clause,
+					    user,
+					    defdomain,
+					    pass,
+					    newpass_crypt);
+	}
+	
 
 	if (!sql_buf)
 	{
@@ -434,53 +819,57 @@
 		return (-1);
 	}
 
-	sprintf(sql_buf, "UPDATE %s SET", user_table);
-
-	comma="";
-
-	if (clear_field && *clear_field)
+	if (!chpass_clause) /*siefca@pld.org.pl */
 	{
-		char *q;
+		sprintf(sql_buf, "UPDATE %s SET", user_table);
 
-		strcat(strcat(strcat(sql_buf, " "), clear_field),
-		       "=\"");
+		comma="";
 
-		q=sql_buf+strlen(sql_buf);
-		while (*pass)
+		if (clear_field && *clear_field)
 		{
-			if (*pass == '"' || *pass == '\\')
-				*q++= '\\';
-			*q++ = *pass++;
+			char *q;
+
+			strcat(strcat(strcat(sql_buf, " "), clear_field),
+		    		"=\"");
+
+			q=sql_buf+strlen(sql_buf);
+			while (*pass)
+			{
+				if (*pass == '"' || *pass == '\\')
+					*q++= '\\';
+				*q++ = *pass++;
+			}
+			strcpy(q, "\"");
+			comma=", ";
 		}
-		strcpy(q, "\"");
-		comma=", ";
-	}
 
-	if (crypt_field && *crypt_field)
-	{
-		strcat(strcat(strcat(strcat(strcat(strcat(sql_buf, comma),
-						   " "),
-					    crypt_field),
-				     "=\""),
-			      newpass_crypt_ptr),
-		       "\"");
-	}
-	free(newpass_crypt);
+		if (crypt_field && *crypt_field)
+		{
+			strcat(strcat(strcat(strcat(strcat(strcat(sql_buf, comma),
+							   " "),
+						    crypt_field),
+					     "=\""),
+			    	newpass_crypt_ptr),
+		    	     "\"");
+		}
+		free(newpass_crypt);
 
-	strcat(strcat(strcat(sql_buf, " WHERE "),
-		      login_field),
-	       "=\"");
+		strcat(strcat(strcat(sql_buf, " WHERE "),
+			      login_field),
+	    	    "=\"");
 
-	append_username(sql_buf+strlen(sql_buf), user, defdomain);
+		append_username(sql_buf+strlen(sql_buf), user, defdomain);
 
-	strcat(sql_buf, "\"");
+		strcat(sql_buf, "\"");
 
-	if (where_clause && *where_clause)
-	{
-		strcat(sql_buf, " AND (");
-		strcat(sql_buf, where_clause);
-		strcat(sql_buf, ")");
-	}
+		if (where_clause && *where_clause)
+		{
+			strcat(sql_buf, " AND (");
+			strcat(sql_buf, where_clause);
+			strcat(sql_buf, ")");
+		}
+		
+	} /* end of: if (!chpass_clause) */
 
 	if (mysql_query (mysql, sql_buf))
 	{
diff -ur courier-imap-1.3.12.orig/authlib/authmysqlrc courier-imap-1.3.12/authlib/authmysqlrc
--- courier-imap-1.3.12.orig/authlib/authmysqlrc	Sun Oct  7 18:32:56 2001
+++ courier-imap-1.3.12/authlib/authmysqlrc	Thu Dec 27 03:43:47 2001
@@ -141,4 +141,65 @@
 #
 # MYSQL_WHERE_CLAUSE	server='mailhost.example.com'
 
-
+##NAME: MYSQL_SELECT_CLAUSE:0
+#
+# (EXPERIMENTAL)
+# This is optional, MYSQL_SELECT_CLAUSE can be set when you have a database,
+# which is structuraly different from proposed. The fixed string will
+# be used to do a SELECT operation on database, which should return fields
+# in order specified bellow:
+#
+# username, cryptpw, uid, gid, clearpw, home, maildir, quota, fullname
+#
+# Enabling this option causes ignorance of any other field-related
+# options, excluding default domain.
+#
+# There are two variables, which you can use. Substitution will be made
+# for them, so you can put entered username (local part) and domain name
+# in the right place of your query. These variables are:
+#	 	$(local_part) and $(domain)
+#
+# If a $(domain) is empty (not given by the remote user) the default domain
+# name is used in its place.
+#
+# This example is a little bit modified adaptation of vmail-sql
+# database scheme:
+#
+# MYSQL_SELECT_CLAUSE	SELECT popbox.local_part,			\
+#			CONCAT('{MD5}', popbox.password_hash),		\
+#			domain.uid,					\
+#			domain.gid,					\
+#			popbox.clearpw,					\
+#			CONCAT(domain.path, '/', popbox.mbox_name),	\
+#			'',						\
+#			domain.quota,					\
+#			'',						\
+#			FROM popbox, domain				\
+#			WHERE popbox.local_part = '$(local_part)'	\
+#			AND popbox.domain_name = '$(domain)'		\
+#			AND popbox.domain_name = domain.domain_name
+#
+##NAME: MYSQL_CHPASS_CLAUSE:0
+#
+# (EXPERIMENTAL)
+# This is optional, MYSQL_CHPASS_CLAUSE can be set when you have a database,
+# which is structuraly different from proposed. The fixed string will
+# be used to do an UPDATE operation on database. In other words, it is
+# used, when changing password.
+#
+# There are four variables, which you can use. Substitution will be made
+# for them, so you can put entered username (local part) and domain name
+# in the right place of your query. There variables are:
+# 	$(local_part) , $(domain) , $(newpass) , $(newpass_crypt)
+#
+# If a $(domain) is empty (not given by the remote user) the default domain
+# name is used in its place.
+# $(newpass) contains plain password
+# $(newpass_crypt) contains its crypted form
+#
+# MYSQL_CHPASS_CLAUSE	UPDATE	popbox					\
+#			SET	clearpw='$(newpass)',			\
+#				password_hash='$(newpass_crypt)'	\
+#			WHERE	local_part='$(local_part)'		\
+#			AND	domain_name='$(domain)'
+#