Add support for simple one-off internal rewrites.

For example:

	location match "/page/(%d+)/.*" {
		request rewrite "/static/index.php?id=%1&$QUERY_STRING"
	}

Requested by many.

Ok benno@

5 files changed, 110 insertions, 18 deletions

diff --git a/usr.sbin/httpd/config.c b/usr.sbin/httpd/config.c
index 42ff4a44b51..0b8c251bc3e 100644
--- a/usr.sbin/httpd/config.c
+++ b/usr.sbin/httpd/config.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: config.c,v 1.54 2018/05/19 13:56:56 jsing Exp $	*/
+/*	$OpenBSD: config.c,v 1.55 2018/06/20 16:43:05 reyk Exp $	*/
 
 /*
  * Copyright (c) 2011 - 2015 Reyk Floeter <reyk@openbsd.org>
@@ -476,6 +476,13 @@ config_getserver_config(struct httpd *env, struct server *srv,
 			    &parent->default_type, sizeof(struct media_type));
 		}
 
+		f = SRVFLAG_PATH_REWRITE|SRVFLAG_NO_PATH_REWRITE;
+		if ((srv_conf->flags & f) == 0) {
+			srv_conf->flags |= parent->flags & f;
+			(void)strlcpy(srv_conf->path, parent->path,
+			    sizeof(srv_conf->path));
+		}
+
 		f = SRVFLAG_SERVER_HSTS;
 		srv_conf->flags |= parent->flags & f;
 		srv_conf->hsts_max_age = parent->hsts_max_age;
diff --git a/usr.sbin/httpd/httpd.conf.5 b/usr.sbin/httpd/httpd.conf.5
index 89837dd0088..f47bc479218 100644
--- a/usr.sbin/httpd/httpd.conf.5
+++ b/usr.sbin/httpd/httpd.conf.5
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: httpd.conf.5,v 1.100 2018/06/18 06:04:25 jmc Exp $
+.\"	$OpenBSD: httpd.conf.5,v 1.101 2018/06/20 16:43:05 reyk Exp $
 .\"
 .\" Copyright (c) 2014, 2015 Reyk Floeter <reyk@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: June 18 2018 $
+.Dd $Mdocdate: June 20 2018 $
 .Dt HTTPD.CONF 5
 .Os
 .Sh NAME
@@ -198,6 +198,8 @@ argument can be used with return codes in the 3xx range to send a
 .Sq Location:
 header for redirection to a specified URI.
 .Pp
+It is possible to rewrite the request to redirect it to a different
+external location.
 The
 .Ar uri
 may contain predefined macros that will be expanded at runtime:
@@ -396,10 +398,10 @@ the
 using pattern matching instead of shell globbing rules,
 see
 .Xr patterns 7 .
-The pattern may contain captures that can be used in the
-.Ar uri
-of an enclosed
+The pattern may contain captures that can be used in an enclosed
 .Ic block return
+or
+.Ic request rewrite
 option.
 .It Oo Ic no Oc Ic log Op Ar option
 Set the specified logging options.
@@ -462,6 +464,19 @@ in a location.
 Configure the options for the request path.
 Valid options are:
 .Bl -tag -width Ds
+.It Oo Ic no Oc Ic rewrite Ar path
+Enable or disable rewriting of the request.
+Unlike the redirection with
+.Ic block return ,
+this will change the request path internally before
+.Nm httpd
+makes a final decision about the matching location.
+The
+.Ar path
+argument may contain predefined macros that will be expanded at runtime.
+See the
+.Ic block return
+option for the list of supported macros.
 .It Ic strip Ar number
 Strip
 .Ar number
@@ -717,6 +732,17 @@ server "www.example.com" {
 	listen on 10.0.0.1 port 80
 }
 .Ed
+The request can also be rewritten with the
+.Ic request rewrite
+directive:
+.Bd -literal -offset indent
+server "example.com" {
+	listen on * port 80
+	location match "/old/(.*)" {
+		request rewrite "/new/%1"
+	}
+}
+.Ed
 .Sh SEE ALSO
 .Xr htpasswd 1 ,
 .Xr patterns 7 ,
diff --git a/usr.sbin/httpd/httpd.h b/usr.sbin/httpd/httpd.h
index aff1a6c5e2a..907989c9bfa 100644
--- a/usr.sbin/httpd/httpd.h
+++ b/usr.sbin/httpd/httpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: httpd.h,v 1.137 2018/05/19 13:56:56 jsing Exp $	*/
+/*	$OpenBSD: httpd.h,v 1.138 2018/06/20 16:43:05 reyk Exp $	*/
 
 /*
  * Copyright (c) 2006 - 2015 Reyk Floeter <reyk@openbsd.org>
@@ -398,13 +398,15 @@ SPLAY_HEAD(client_tree, client);
 #define SRVFLAG_SERVER_MATCH	0x00200000
 #define SRVFLAG_SERVER_HSTS	0x00400000
 #define SRVFLAG_DEFAULT_TYPE	0x00800000
+#define SRVFLAG_PATH_REWRITE	0x01000000
+#define SRVFLAG_NO_PATH_REWRITE	0x02000000
 
 #define SRVFLAG_BITS							\
 	"\10\01INDEX\02NO_INDEX\03AUTO_INDEX\04NO_AUTO_INDEX"		\
 	"\05ROOT\06LOCATION\07FCGI\10NO_FCGI\11LOG\12NO_LOG\13SOCKET"	\
 	"\14SYSLOG\15NO_SYSLOG\16TLS\17ACCESS_LOG\20ERROR_LOG"		\
 	"\21AUTH\22NO_AUTH\23BLOCK\24NO_BLOCK\25LOCATION_MATCH"		\
-	"\26SERVER_MATCH\27SERVER_HSTS\30DEFAULT_TYPE"
+	"\26SERVER_MATCH\27SERVER_HSTS\30DEFAULT_TYPE\31PATH\32NO_PATH"
 
 #define TCPFLAG_NODELAY		0x01
 #define TCPFLAG_NNODELAY	0x02
@@ -470,8 +472,9 @@ struct server_config {
 	uint32_t		 parent_id;
 	char			 name[HOST_NAME_MAX+1];
 	char			 location[HTTPD_LOCATION_MAX];
-	char			 index[PATH_MAX];
 	char			 root[PATH_MAX];
+	char			 path[PATH_MAX];
+	char			 index[PATH_MAX];
 	char			 socket[PATH_MAX];
 	char			 accesslog[PATH_MAX];
 	char			 errorlog[PATH_MAX];
diff --git a/usr.sbin/httpd/parse.y b/usr.sbin/httpd/parse.y
index 0dc283b2705..49beb33a350 100644
--- a/usr.sbin/httpd/parse.y
+++ b/usr.sbin/httpd/parse.y
@@ -1,4 +1,4 @@
-/*	$OpenBSD: parse.y,v 1.102 2018/06/13 15:08:24 reyk Exp $	*/
+/*	$OpenBSD: parse.y,v 1.103 2018/06/20 16:43:05 reyk Exp $	*/
 
 /*
  * Copyright (c) 2007 - 2015 Reyk Floeter <reyk@openbsd.org>
@@ -139,7 +139,7 @@ typedef struct {
 %token	LISTEN LOCATION LOG LOGDIR MATCH MAXIMUM NO NODELAY OCSP ON PORT PREFORK
 %token	PROTOCOLS REQUESTS ROOT SACK SERVER SOCKET STRIP STYLE SYSLOG TCP TICKET
 %token	TIMEOUT TLS TYPE TYPES HSTS MAXAGE SUBDOMAINS DEFAULT PRELOAD REQUEST
-%token	ERROR INCLUDE AUTHENTICATE WITH BLOCK DROP RETURN PASS
+%token	ERROR INCLUDE AUTHENTICATE WITH BLOCK DROP RETURN PASS REWRITE
 %token	CA CLIENT CRL OPTIONAL
 %token	<v.string>	STRING
 %token  <v.number>	NUMBER
@@ -820,7 +820,23 @@ requestflags_l	: requestflags optcommanl requestflags_l
 		| requestflags optnl
 		;
 
-requestflags	: STRIP NUMBER			{
+requestflags	: REWRITE STRING		{
+			if (strlcpy(srv->srv_conf.path, $2,
+			    sizeof(srv->srv_conf.path)) >=
+			    sizeof(srv->srv_conf.path)) {
+				yyerror("request path too long");
+				free($2);
+				YYERROR;
+			}
+			free($2);
+			srv->srv_conf.flags |= SRVFLAG_PATH_REWRITE;
+			srv->srv_conf.flags &= ~SRVFLAG_NO_PATH_REWRITE;
+		}
+		| NO REWRITE			{
+			srv->srv_conf.flags |= SRVFLAG_NO_PATH_REWRITE;
+			srv->srv_conf.flags &= ~SRVFLAG_PATH_REWRITE;
+		}
+		| STRIP NUMBER			{
 			if ($2 < 0 || $2 > INT_MAX) {
 				yyerror("invalid strip number");
 				YYERROR;
@@ -1277,6 +1293,7 @@ lookup(char *s)
 		{ "request",		REQUEST },
 		{ "requests",		REQUESTS },
 		{ "return",		RETURN },
+		{ "rewrite",		REWRITE },
 		{ "root",		ROOT },
 		{ "sack",		SACK },
 		{ "server",		SERVER },
diff --git a/usr.sbin/httpd/server_http.c b/usr.sbin/httpd/server_http.c
index 5ee51b1925f..4c91dea2d16 100644
--- a/usr.sbin/httpd/server_http.c
+++ b/usr.sbin/httpd/server_http.c
@@ -1,7 +1,7 @@
-/*	$OpenBSD: server_http.c,v 1.121 2018/06/15 12:36:05 reyk Exp $	*/
+/*	$OpenBSD: server_http.c,v 1.122 2018/06/20 16:43:05 reyk Exp $	*/
 
 /*
- * Copyright (c) 2006 - 2017 Reyk Floeter <reyk@openbsd.org>
+ * Copyright (c) 2006 - 2018 Reyk Floeter <reyk@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -1170,13 +1170,16 @@ server_response(struct httpd *httpd, struct client *clt)
 	struct kv		*kv, key, *host;
 	struct str_find		 sm;
 	int			 portval = -1, ret;
-	char			*hostval;
+	char			*hostval, *query;
 	const char		*errstr = NULL;
 
-	/* Canonicalize the request path */
+	/* Decode the URL */
 	if (desc->http_path == NULL ||
-	    url_decode(desc->http_path) == NULL ||
-	    canonicalize_path(desc->http_path, path, sizeof(path)) == NULL)
+	    url_decode(desc->http_path) == NULL)
+		goto fail;
+
+	/* Canonicalize the request path */
+	if (canonicalize_path(desc->http_path, path, sizeof(path)) == NULL)
 		goto fail;
 	free(desc->http_path);
 	if ((desc->http_path = strdup(path)) == NULL)
@@ -1280,6 +1283,42 @@ server_response(struct httpd *httpd, struct client *clt)
 	/* Now search for the location */
 	srv_conf = server_getlocation(clt, desc->http_path);
 
+	/* Optional rewrite */
+	if (srv_conf->flags & SRVFLAG_PATH_REWRITE) {
+		/* Expand macros */
+		if (server_expand_http(clt, srv_conf->path,
+		    path, sizeof(path)) == NULL)
+			goto fail;
+
+		/*
+		 * Reset and update the query.  The updated query must already
+		 * be URL encoded - either specified by the user or by using the
+		 * original $QUERY_STRING.
+		 */
+		free(desc->http_query);
+		desc->http_query = NULL;
+		if ((query = strchr(path, '?')) != NULL) {
+			*query++ = '\0';
+			if ((desc->http_query = strdup(query)) == NULL)
+				goto fail;
+		}
+
+		/* Canonicalize the updated request path */
+		if (canonicalize_path(path,
+		    path, sizeof(path)) == NULL)
+			goto fail;
+
+		log_debug("%s: rewrote %s -> %s?%s", __func__,
+		    desc->http_path, path, desc->http_query);
+
+		free(desc->http_path);
+		if ((desc->http_path = strdup(path)) == NULL)
+			goto fail;
+
+		/* Now search for the updated location */
+		srv_conf = server_getlocation(clt, desc->http_path);
+	}
+
 	if (srv_conf->flags & SRVFLAG_BLOCK) {
 		server_abort_http(clt, srv_conf->return_code,
 		    srv_conf->return_uri);