Add support for TLS streams

.gitmodules

@@ -7,3 +7,9 @@
 [submodule "subprojects/lolibc"]
 	path = subprojects/lolibc
 	url = http://github.com/dimkr/lolibc
+[submodule "src/mbedtls"]
+	path = src/mbedtls
+	url = https://github.com/ARMmbed/mbedtls
+[submodule "src/curl"]
+	path = src/curl
+	url = https://github.com/curl/curl

docs/ssl.md

@@ -0,0 +1,9 @@
+    {$ssl.client 3 localhost 0}
+
+*ssl.client* creates a TLS client stream, using the file descriptor of a TCP client stream. The optional third argument determines whether or not certificate validation is enabled.
+
+**If the third argument is omitted**, certificate validation is enabled.
+
+    {$ssl.server server.crt server.key}
+
+*ssl.server* creates a TLS server.

examples/httpd.b6b

@@ -3,7 +3,7 @@
 {#
 	This file is part of b6b.
 
-	Copyright 2017, 2018 Dima Krasner
+	Copyright 2017, 2018, 2022 Dima Krasner
 
 	Licensed under the Apache License, Version 2.0 (the "License");
 	you may not use this file except in compliance with the License.
@@ -206,19 +206,33 @@
 			{$return}
 		}}
 
-		{$http.loop add $client $on_request {} $on_error}
+		{$proc _ {
+			{$try {
+				{$local ssl_client [$ssl_server accept [$. fd]]}
+				{$http.loop add $ssl_client $on_request {} $on_error}
+			} {
+				{$http.loop remove $.}
+				{$. close}
+			}}
+		} $client}
+
+		{$spawn {
+			{$_}
+		}}
 	}}
 }}
 
 {$proc on_banner {
 	{$global http.banner [$choice $http.banners]}
 }}
 
-{$if [$!= [$list.len $@] 4] {
-	{$stderr writeln {Usage: httpd addr port backlog}}
+{$if [$!= [$list.len $@] 6] {
+	{$stderr writeln {Usage: httpd addr port backlog cert key}}
 	{$exit 1}
 }}
 
+{$global ssl_server [$ssl.server $4 $5]}
+
 {$http.loop add [$signal $SIGTERM $SIGINT] $on_term {} {}}
 {$http.loop add [$inet.server tcp $1 $2 $3] $on_clients {} {}}
 {# periodically change the server banner}

meson_options.txt

@@ -1,6 +1,6 @@
 # This file is part of b6b.
 #
-# Copyright 2017 Dima Krasner
+# Copyright 2017, 2022 Dima Krasner
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -19,3 +19,4 @@ option('with_miniz', type: 'boolean')
 option('with_linenoise', type: 'boolean')
 option('with_valgrind', type: 'boolean', value: false)
 option('optimistic_alloc', type: 'boolean')
+option('with_mbedtls', type: 'boolean')

src/b6b_interp.c

@@ -485,8 +485,6 @@ int b6b_offload(struct b6b_interp *interp,
                 void (*fn)(void *),
                 void *arg)
 {
-	struct b6b_thread *t;
-	int swap, pending = 0;
 	struct b6b_offload_thread *offth = NULL;
 
 	if (!b6b_threaded(interp))
@@ -519,31 +517,6 @@ int b6b_offload(struct b6b_interp *interp,
 			if (!b6b_threaded(interp))
 				break;
 
-			/* check whether there is at least one thread that waits for us to
-			 * complete the blocking operation and at least one thread which
-			 * doesn't */
-			pending = swap = 0;
-			b6b_thread_foreach(&interp->threads, t) {
-				if (t != interp->fg) {
-					if (b6b_thread_blocked(t)) {
-						pending = 1;
-						if (swap)
-							break;
-					}
-					else {
-						swap = 1;
-						if (pending)
-							break;
-					}
-				}
-			}
-
-			/* if all other threads are blocked by us, we want to stop this
-			 * polling loop since all they do is repeatedly calling
-			 * b6b_yield() */
-			if (!swap)
-				break;
-
 			/* if all other threads exited during the previous iterations of
 			 * this loop, we can (and should) block */
 			if (!b6b_yield(interp))
@@ -560,8 +533,7 @@ int b6b_offload(struct b6b_interp *interp,
 		 * the next statement of the current thread also calls
 		 * b6b_offload_start(), that thread will spend more time in its
 		 * b6b_offload_ready() loop */
-		if (pending)
-			b6b_yield(interp);
+		b6b_yield(interp);
 	}
 
 	return 1;