From 3614ae6eb7b6101fa5d0f14ff0d3a6eb4970c3da Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Wed, 7 Oct 2015 16:21:10 +0200
Subject: [PATCH] add a -y parameter for cgi-bin redirects

this allows an alias entry inside the root folder point at a cgi-bin script

-y foo=bar will redirect /foo to /cgi-bin/bar

Signed-off-by: John Crispin <blogic@openwrt.org>
---
 file.c   | 42 ++++++++++++++++++++++++++++++++++++++++++
 main.c   | 21 +++++++++++++++++++--
 uhttpd.h |  8 ++++++++
 3 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/file.c b/file.c
index 9946d7c..6b5020f 100644
--- a/file.c
+++ b/file.c
@@ -33,6 +33,8 @@
 #include "uhttpd.h"
 #include "mimetypes.h"
 
+#define MAX(a, b)	(((a) > (b)) ? (a) : (b))
+
 static LIST_HEAD(index_files);
 static LIST_HEAD(dispatch_handlers);
 static LIST_HEAD(pending_requests);
@@ -815,6 +817,44 @@ static bool __handle_file_request(struct client *cl, char *url)
 	return true;
 }
 
+static char *uh_handle_alias(char *old_url)
+{
+	struct alias *alias;
+	static char *new_url;
+	static int url_len;
+
+	if (!list_empty(&conf.cgi_alias)) list_for_each_entry(alias, &conf.cgi_alias, list) {
+		int old_len;
+		int new_len;
+		int path_len = 0;
+
+		if (uh_path_match(alias->alias, old_url))
+			continue;
+
+		if (alias->path)
+			path_len = strlen(alias->path);
+
+		old_len = strlen(old_url) + 1;
+		new_len = old_len + MAX(conf.cgi_prefix_len, path_len);
+
+		if (new_len > url_len) {
+			new_url = realloc(new_url, new_len);
+			url_len = new_len;
+		}
+
+		*new_url = '\0';
+
+		if (alias->path)
+			strcpy(new_url, alias->path);
+		else if (conf.cgi_prefix)
+			strcpy(new_url, conf.cgi_prefix);
+		strcat(new_url, old_url);
+
+		return new_url;
+	}
+	return old_url;
+}
+
 void uh_handle_request(struct client *cl)
 {
 	struct http_request *req = &cl->request;
@@ -822,6 +862,8 @@ void uh_handle_request(struct client *cl)
 	char *url = blobmsg_data(blob_data(cl->hdr.head));
 	char *error_handler;
 
+	url = uh_handle_alias(url);
+
 	req->redirect_status = 200;
 	d = dispatch_find(url, NULL);
 	if (d)
diff --git a/main.c b/main.c
index ed47486..ae54b69 100644
--- a/main.c
+++ b/main.c
@@ -155,6 +155,7 @@ static int usage(const char *name)
 		"	-X		Enable CORS HTTP headers on JSON-RPC api\n"
 #endif
 		"	-x string       URL prefix for CGI handler, default is '/cgi-bin'\n"
+		"	-y alias[=path]	URL alias handle\n"
 		"	-i .ext=path    Use interpreter at path for files with the given extension\n"
 		"	-t seconds      CGI, Lua and UBUS script timeout in seconds, default is 60\n"
 		"	-T seconds      Network timeout in seconds, default is 30\n"
@@ -177,6 +178,7 @@ static void init_defaults_pre(void)
 	conf.realm = "Protected Area";
 	conf.cgi_prefix = "/cgi-bin";
 	conf.cgi_path = "/sbin:/usr/sbin:/bin:/usr/bin";
+	INIT_LIST_HEAD(&conf.cgi_alias);
 }
 
 static void init_defaults_post(void)
@@ -188,9 +190,11 @@ static void init_defaults_post(void)
 
 	if (conf.cgi_prefix) {
 		char *str = malloc(strlen(conf.docroot) + strlen(conf.cgi_prefix) + 1);
+
 		strcpy(str, conf.docroot);
 		strcat(str, conf.cgi_prefix);
 		conf.cgi_docroot_path = str;
+		conf.cgi_prefix_len = strlen(conf.cgi_prefix);
 	};
 }
 
@@ -211,12 +215,12 @@ static void fixup_prefix(char *str)
 
 int main(int argc, char **argv)
 {
+	struct alias *alias;
 	bool nofork = false;
 	char *port;
 	int opt, ch;
 	int cur_fd;
 	int bound = 0;
-
 #ifdef HAVE_TLS
 	int n_tls = 0;
 	const char *tls_key = NULL, *tls_crt = NULL;
@@ -228,7 +232,7 @@ int main(int argc, char **argv)
 	init_defaults_pre();
 	signal(SIGPIPE, SIG_IGN);
 
-	while ((ch = getopt(argc, argv, "afqSDRXC:K:E:I:p:s:h:c:l:L:d:r:m:n:N:x:i:t:k:T:A:u:U:")) != -1) {
+	while ((ch = getopt(argc, argv, "afqSDRXC:K:E:I:p:s:h:c:l:L:d:r:m:n:N:x:y:i:t:k:T:A:u:U:")) != -1) {
 		switch(ch) {
 #ifdef HAVE_TLS
 		case 'C':
@@ -312,6 +316,19 @@ int main(int argc, char **argv)
 			conf.cgi_prefix = optarg;
 			break;
 
+		case 'y':
+			alias = calloc(1, sizeof(*alias));
+			if (!alias) {
+				fprintf(stderr, "Error: failed to allocate alias\n");
+				exit(1);
+			}
+			alias->alias = strdup(optarg);
+			alias->path = strchr(alias->alias, '=');
+			if (alias->path)
+				*alias->path++ = 0;
+			list_add(&alias->list, &conf.cgi_alias);
+			break;
+
 		case 'i':
 			optarg = strdup(optarg);
 			port = strchr(optarg, '=');
diff --git a/uhttpd.h b/uhttpd.h
index be9ee7f..897d4b3 100644
--- a/uhttpd.h
+++ b/uhttpd.h
@@ -46,6 +46,12 @@
 
 struct client;
 
+struct alias {
+	struct list_head list;
+	char *alias;
+	char *path;
+};
+
 struct config {
 	const char *docroot;
 	const char *realm;
@@ -70,6 +76,8 @@ struct config {
 	int script_timeout;
 	int ubus_noauth;
 	int ubus_cors;
+	int cgi_prefix_len;
+	struct list_head cgi_alias;
 };
 
 struct auth_realm {
-- 
2.25.1