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Re: [Libevent-users] Re: Avoid potential SSL read spinlocks
On Tue, Nov 15, 2011 at 10:25 AM, Mark Ellzey <mthomas@xxxxxxxxxx> wrote:
> Also, would be nice to have some code that reproduces the issue you are
> having.
Ok, try the attached patch against 9ae6e595 (just before your fixes).
The use of an IP in the URL is incidental because of IPv6 issues on my
system - you can probably use www.google.com directly.
$ .libs/https-client https://74.125.224.80/
<snip>
Response line: 302 Found
> <HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="http://www.google.com/";>here</A>.
</BODY></HTML>
[err] ../libevent/http.c:704: Assertion req != NULL failed in
evhttp_connection_fail
Aborted
From 09e940ef9b71b612037e04b74f94879bfcbebd6a Mon Sep 17 00:00:00 2001
From: Catalin Patulea <catalinp@xxxxxxxxxx>
Date: Wed, 16 Nov 2011 11:22:04 -0800
Subject: [PATCH] Add sample/https-client.c, an example of stacking evhttp as a client on top of bufferevent_ssl.
This reproduces an assert(req != NULL) in evhttp_connection_fail for me.
---
sample/Makefile.am | 4 +
sample/https-client.c | 205 +++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 209 insertions(+), 0 deletions(-)
create mode 100644 sample/https-client.c
diff --git a/sample/Makefile.am b/sample/Makefile.am
index 61e72d6..2147b29 100644
--- a/sample/Makefile.am
+++ b/sample/Makefile.am
@@ -17,6 +17,10 @@ AM_CPPFLAGS += $(OPENSSL_INCS)
noinst_PROGRAMS += le-proxy
le_proxy_SOURCES = le-proxy.c
le_proxy_LDADD = $(LDADD) ../libevent_openssl.la -lssl -lcrypto
+
+noinst_PROGRAMS += https-client
+https_client_SOURCES = https-client.c
+https_client_LDADD = $(LDADD) ../libevent_openssl.la -lssl -lcrypto
endif
verify:
diff --git a/sample/https-client.c b/sample/https-client.c
new file mode 100644
index 0000000..5013c68
--- /dev/null
+++ b/sample/https-client.c
@@ -0,0 +1,205 @@
+/*
+ This is an example of how to hook up evhttp with bufferevent_ssl
+
+ It just GETs an https URL given on the command-line and prints the response
+ body to stdout.
+
+ Actually, it also accepts plain http URLs to make it easy to compare http vs
+ https code paths.
+
+ Loosely based on le-proxy.c.
+ */
+
+#include <stdio.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#ifdef WIN32
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#else
+#include <sys/socket.h>
+#include <netinet/in.h>
+#endif
+
+#include <event2/bufferevent_ssl.h>
+#include <event2/bufferevent.h>
+#include <event2/buffer.h>
+#include <event2/listener.h>
+#include <event2/util.h>
+#include <event2/http.h>
+#include <event2/http_struct.h>
+
+#include <openssl/ssl.h>
+#include <openssl/err.h>
+#include <openssl/rand.h>
+
+static struct event_base *base;
+
+static void
+http_request_done(struct evhttp_request *req, void *ctx)
+{
+ char buffer[256];
+ int nread;
+
+ if (req == NULL) {
+ fprintf(stderr, "some request failed - no idea which one though!\n");
+ return;
+ }
+
+ fprintf(stderr, "Response line: %d %s\n",
+ req->response_code, req->response_code_line);
+
+ while ((nread = evbuffer_remove(req->input_buffer, buffer, sizeof(buffer))) > 0) {
+ fwrite("> ", 2, 1, stdout);
+ fwrite(buffer, nread, 1, stdout);
+ fwrite("\n", 1, 1, stdout);
+ }
+}
+
+static void
+syntax(void)
+{
+ fputs("Syntax:\n", stderr);
+ fputs(" https-client <https-url>\n", stderr);
+ fputs("Example:\n", stderr);
+ fputs(" https-client https://ipcheckit.com/\n";, stderr);
+
+ exit(1);
+}
+
+static void
+die(const char *msg)
+{
+ fputs(msg, stderr);
+ exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+ int r;
+
+ struct evhttp_uri *http_uri;
+ const char *url, *scheme, *host, *path, *query;
+ char uri[256];
+ int port;
+
+ SSL_CTX *ssl_ctx;
+ SSL *ssl;
+ struct bufferevent *bev;
+ struct evhttp_connection *evcon;
+ struct evhttp_request *req;
+
+ if (argc != 2)
+ syntax();
+
+ url = argv[1];
+ http_uri = evhttp_uri_parse(url);
+ if (http_uri == NULL) {
+ die("malformed url");
+ }
+
+ scheme = evhttp_uri_get_scheme(http_uri);
+ if (scheme == NULL || (strcasecmp(scheme, "https") != 0 &&
+ strcasecmp(scheme, "http") != 0)) {
+ die("url must be http or https");
+ }
+
+ host = evhttp_uri_get_host(http_uri);
+ if (host == NULL) {
+ die("url must have a host");
+ }
+
+ port = evhttp_uri_get_port(http_uri);
+ if (port == -1) {
+ port = (strcasecmp(scheme, "http") == 0) ? 80 : 443;
+ }
+
+ path = evhttp_uri_get_path(http_uri);
+ if (path == NULL) {
+ path = "/";
+ }
+
+ query = evhttp_uri_get_query(http_uri);
+ if (query == NULL) {
+ snprintf(uri, sizeof(uri) - 1, "%s", path);
+ } else {
+ snprintf(uri, sizeof(uri) - 1, "%s?%s", path, query);
+ }
+ uri[sizeof(uri) - 1] = '\0';
+
+ // Initialize OpenSSL
+ SSL_library_init();
+ ERR_load_crypto_strings();
+ SSL_load_error_strings();
+ OpenSSL_add_all_algorithms();
+ r = RAND_poll();
+ if (r == 0) {
+ fprintf(stderr, "RAND_poll() failed.\n");
+ return 1;
+ }
+ ssl_ctx = SSL_CTX_new(SSLv23_method());
+
+ // Create event base
+ base = event_base_new();
+ if (!base) {
+ perror("event_base_new()");
+ return 1;
+ }
+
+ // Create OpenSSL bufferevent and stack evhttp on top of it
+ ssl = SSL_new(ssl_ctx);
+ if (ssl == NULL) {
+ fprintf(stderr, "SSL_new() failed\n");
+ return 1;
+ }
+
+ if (strcasecmp(scheme, "http") == 0) {
+ bev = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
+ } else {
+ bev = bufferevent_openssl_socket_new(base, -1, ssl,
+ BUFFEREVENT_SSL_CONNECTING,
+ BEV_OPT_CLOSE_ON_FREE|BEV_OPT_DEFER_CALLBACKS);
+ }
+
+ if (bev == NULL) {
+ fprintf(stderr, "bufferevent_openssl_socket_new() failed\n");
+ return 1;
+ }
+
+ // For simplicity, we let DNS resolution block. Everything else should be
+ // asynchronous though.
+ evcon = evhttp_connection_base_bufferevent_new(base, NULL, bev,
+ host, port);
+ if (evcon == NULL) {
+ fprintf(stderr, "evhttp_connection_base_bufferevent_new() failed\n");
+ return 1;
+ }
+
+ // Fire off the request
+ req = evhttp_request_new(http_request_done, NULL);
+ if (req == NULL) {
+ fprintf(stderr, "evhttp_request_new() failed\n");
+ return 1;
+ }
+
+ evhttp_add_header(req->output_headers, "Host", host);
+ evhttp_add_header(req->output_headers, "Connection", "close");
+
+ r = evhttp_make_request(evcon, req, EVHTTP_REQ_GET, uri);
+ if (r != 0) {
+ fprintf(stderr, "evhttp_make_request() failed\n");
+ return 1;
+ }
+
+ event_base_dispatch(base);
+
+ evhttp_connection_free(evcon);
+ event_base_free(base);
+
+ return 0;
+}
+
--
1.7.3.1