]> granicus.if.org Git - apache/commitdiff
[mod_proxy_]http: follow up to r1750392.
authorYann Ylavic <ylavic@apache.org>
Fri, 12 Aug 2016 13:58:10 +0000 (13:58 +0000)
committerYann Ylavic <ylavic@apache.org>
Fri, 12 Aug 2016 13:58:10 +0000 (13:58 +0000)
Export [ap_]check_pipeline() and use it also for ap_proxy_check_connection(),
so that all the necessary checks on the connection are done before reusing it.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1756186 13f79535-47bb-0310-9956-ffa450edef68

include/ap_mmn.h
include/http_request.h
modules/http/http_request.c
modules/proxy/mod_proxy.h
modules/proxy/mod_proxy_ajp.c
modules/proxy/mod_proxy_fcgi.c
modules/proxy/mod_proxy_http.c
modules/proxy/proxy_util.c

index d0d8c889eb1ddbbf4c9f6ac7cf6c204a2085152a..19d13d862ad73a66e5c03c62d55f3343478b08ca 100644 (file)
  *                         dav_success_proppatch.
  * 20160608.4 (2.5.0-dev)  Add dav_acl_provider, dav_acl_provider_register
  *                         dav_get_acl_providers.
- * 20160608.5 (2.5.0-dev)  Add ap_proxy_check_backend(), and tmp_bb to struct
- *                         proxy_conn_rec.
+ * 20160608.5 (2.5.0-dev)  Add ap_proxy_check_connection(), and tmp_bb to
+ *                         struct proxy_conn_rec.
  * 20160608.6 (2.5.0-dev)  Add ap_scan_http_field_content, ap_scan_http_token
  *                         and ap_get_http_token
+ * 20160608.7 (2.5.0-dev)  Add ap_check_pipeline().
  */
 
 #define MODULE_MAGIC_COOKIE 0x41503235UL /* "AP25" */
 #ifndef MODULE_MAGIC_NUMBER_MAJOR
 #define MODULE_MAGIC_NUMBER_MAJOR 20160608
 #endif
-#define MODULE_MAGIC_NUMBER_MINOR 6                 /* 0...n */
+#define MODULE_MAGIC_NUMBER_MINOR 7                 /* 0...n */
 
 /**
  * Determine if the server's current MODULE_MAGIC_NUMBER is at least a
index 4d82c8a3fe4206474488174dd576b0c59e22e427..1eb30e52b28a783ee7f6db031c105bbd4eabad46 100644 (file)
@@ -350,6 +350,21 @@ void ap_process_async_request(request_rec *r);
  */
 AP_DECLARE(void) ap_die(int type, request_rec *r);
 
+/**
+ * Check whether a connection is still established and has data available,
+ * optionnaly consuming blank lines ([CR]LF).
+ * @param c The current connection
+ * @param bb The brigade to filter
+ * @param max_blank_lines Max number of blank lines to consume, or zero
+ *                        to consider them as data (single read).
+ * @return APR_SUCCESS: connection established with data available,
+ *         APR_EAGAIN: connection established and empty,
+ *         APR_NOTFOUND: too much blank lines,
+ *         APR_E*: connection/general error.
+ */
+AP_DECLARE(apr_status_t) ap_check_pipeline(conn_rec *c, apr_bucket_brigade *bb,
+                                           unsigned int max_blank_lines);
+
 /* Hooks */
 
 /**
index ee50b4232a7d6179afff7cb390489118d0b68239..aa0511277dee61c93a62295fc7dd9fe04b5d6614 100644 (file)
@@ -229,41 +229,51 @@ AP_DECLARE(void) ap_die(int type, request_rec *r)
     ap_die_r(type, r, r->status);
 }
 
-static void check_pipeline(conn_rec *c, apr_bucket_brigade *bb)
+AP_DECLARE(apr_status_t) ap_check_pipeline(conn_rec *c, apr_bucket_brigade *bb,
+                                           unsigned int max_blank_lines)
 {
-    apr_status_t rv;
-    int num_blank_lines = DEFAULT_LIMIT_BLANK_LINES;
+    apr_status_t rv = APR_EOF;
     ap_input_mode_t mode = AP_MODE_SPECULATIVE;
+    unsigned int num_blank_lines = 0;
     apr_size_t cr = 0;
     char buf[2];
 
-    c->data_in_input_filters = 0;
     while (c->keepalive != AP_CONN_CLOSE && !c->aborted) {
         apr_size_t len = cr + 1;
 
         apr_brigade_cleanup(bb);
         rv = ap_get_brigade(c->input_filters, bb, mode,
                             APR_NONBLOCK_READ, len);
-        if (rv != APR_SUCCESS || APR_BRIGADE_EMPTY(bb)) {
-            /*
-             * Error or empty brigade: There is no data present in the input
-             * filter
-             */
+        if (rv != APR_SUCCESS || APR_BRIGADE_EMPTY(bb) || !max_blank_lines) {
             if (mode == AP_MODE_READBYTES) {
                 /* Unexpected error, stop with this connection */
                 ap_log_cerror(APLOG_MARK, APLOG_ERR, rv, c, APLOGNO(02967)
                               "Can't consume pipelined empty lines");
                 c->keepalive = AP_CONN_CLOSE;
+                rv = APR_EGENERAL;
+            }
+            else if (rv != APR_SUCCESS || APR_BRIGADE_EMPTY(bb)) {
+                if (rv != APR_SUCCESS && !APR_STATUS_IS_EAGAIN(rv)) {
+                    /* Pipe is dead */
+                    c->keepalive = AP_CONN_CLOSE;
+                }
+                else {
+                    /* Pipe is up and empty */
+                    rv = APR_EAGAIN;
+                }
+            }
+            else {
+                apr_off_t n = 0;
+                /* Single read asked, (non-meta-)data available? */
+                rv = apr_brigade_length(bb, 0, &n);
+                if (rv == APR_SUCCESS && n <= 0) {
+                    rv = APR_EAGAIN;
+                }
             }
             break;
         }
 
-        /* Ignore trailing blank lines (which must not be interpreted as
-         * pipelined requests) up to the limit, otherwise we would block
-         * on the next read without flushing data, and hence possibly delay
-         * pending response(s) until the next/real request comes in or the
-         * keepalive timeout expires.
-         */
+        /* Lookup and consume blank lines */
         rv = apr_brigade_flatten(bb, buf, &len);
         if (rv != APR_SUCCESS || len != cr + 1) {
             int log_level;
@@ -271,14 +281,15 @@ static void check_pipeline(conn_rec *c, apr_bucket_brigade *bb)
                 /* Unexpected error, stop with this connection */
                 c->keepalive = AP_CONN_CLOSE;
                 log_level = APLOG_ERR;
+                rv = APR_EGENERAL;
             }
             else {
                 /* Let outside (non-speculative/blocking) read determine
                  * where this possible failure comes from (metadata,
-                 * morphed EOF socket => empty bucket? debug only here).
+                 * morphed EOF socket, ...). Debug only here.
                  */
-                c->data_in_input_filters = 1;
                 log_level = APLOG_DEBUG;
+                rv = APR_SUCCESS;
             }
             ap_log_cerror(APLOG_MARK, log_level, rv, c, APLOGNO(02968)
                           "Can't check pipelined data");
@@ -286,40 +297,47 @@ static void check_pipeline(conn_rec *c, apr_bucket_brigade *bb)
         }
 
         if (mode == AP_MODE_READBYTES) {
+            /* [CR]LF consumed, try next */
             mode = AP_MODE_SPECULATIVE;
             cr = 0;
         }
         else if (cr) {
             AP_DEBUG_ASSERT(len == 2 && buf[0] == APR_ASCII_CR);
             if (buf[1] == APR_ASCII_LF) {
+                /* consume this CRLF */
                 mode = AP_MODE_READBYTES;
-                num_blank_lines--;
+                num_blank_lines++;
             }
             else {
-                c->data_in_input_filters = 1;
+                /* CR(?!LF) is data */
                 break;
             }
         }
         else {
             if (buf[0] == APR_ASCII_LF) {
+                /* consume this LF */
                 mode = AP_MODE_READBYTES;
-                num_blank_lines--;
+                num_blank_lines++;
             }
             else if (buf[0] == APR_ASCII_CR) {
                 cr = 1;
             }
             else {
-                c->data_in_input_filters = 1;
+                /* Not [CR]LF, some data */
                 break;
             }
         }
-        /* Enough blank lines with this connection?
-         * Stop and don't recycle it.
-         */
-        if (num_blank_lines < 0) {
+        if (num_blank_lines > max_blank_lines) {
+            /* Enough blank lines with this connection,
+             * stop and don't recycle it.
+             */
             c->keepalive = AP_CONN_CLOSE;
+            rv = APR_NOTFOUND;
+            break;
         }
     }
+
+    return rv;
 }
 
 
@@ -328,6 +346,7 @@ AP_DECLARE(void) ap_process_request_after_handler(request_rec *r)
     apr_bucket_brigade *bb;
     apr_bucket *b;
     conn_rec *c = r->connection;
+    apr_status_t rv;
 
     /* Send an EOR bucket through the output filter chain.  When
      * this bucket is destroyed, the request will be logged and
@@ -360,8 +379,15 @@ AP_DECLARE(void) ap_process_request_after_handler(request_rec *r)
      * already by the EOR bucket's cleanup function.
      */
 
-    check_pipeline(c, bb);
+    /* Check pipeline consuming blank lines, they must not be interpreted as
+     * the next pipelined request, otherwise we would block on the next read
+     * without flushing data, and hence possibly delay pending response(s)
+     * until the next/real request comes in or the keepalive timeout expires.
+     */
+    rv = ap_check_pipeline(c, bb, DEFAULT_LIMIT_BLANK_LINES);
+    c->data_in_input_filters = (rv == APR_SUCCESS);
     apr_brigade_destroy(bb);
+
     if (c->cs)
         c->cs->state = (c->aborted) ? CONN_STATE_LINGER
                                     : CONN_STATE_WRITE_COMPLETION;
index 9a4812a44b7d7c8cd2b62cd9333b5f0dd4215d70..ba78317bbe6d247575d99ef71f241f37ba595694 100644 (file)
@@ -671,7 +671,7 @@ PROXY_DECLARE(int) ap_proxy_checkproxyblock(request_rec *r, proxy_server_conf *c
 PROXY_DECLARE(int) ap_proxy_pre_http_request(conn_rec *c, request_rec *r);
 /* DEPRECATED (will be replaced with ap_proxy_connect_backend */
 PROXY_DECLARE(int) ap_proxy_connect_to_backend(apr_socket_t **, const char *, apr_sockaddr_t *, const char *, proxy_server_conf *, request_rec *);
-/* DEPRECATED (will be replaced with ap_proxy_check_backend */
+/* DEPRECATED (will be replaced with ap_proxy_check_connection */
 PROXY_DECLARE(apr_status_t) ap_proxy_ssl_connection_cleanup(proxy_conn_rec *conn,
                                                             request_rec *r);
 PROXY_DECLARE(int) ap_proxy_ssl_enable(conn_rec *c);
@@ -977,22 +977,27 @@ PROXY_DECLARE(int) ap_proxy_acquire_connection(const char *proxy_function,
 PROXY_DECLARE(int) ap_proxy_release_connection(const char *proxy_function,
                                                proxy_conn_rec *conn,
                                                server_rec *s);
+
+#define PROXY_CHECK_CONN_EMPTY (1 << 0)
 /**
  * Check a connection to the backend
- * @param proxy_function calling proxy scheme (http, ajp, ...)
- * @param conn    acquired connection
- * @param s       current server record
- * @param expect_empty whether to check for empty (no data available) or not
- * @return        APR_SUCCESS or,
- *                APR_ENOTSOCK: not connected,
- *                APR_NOTFOUND: worker in error state (unusable),
- *                APR_ENOTEMPTY: expect_empty set but the connection has data,
- *                other: connection closed/aborted (remotely)
+ * @param scheme calling proxy scheme (http, ajp, ...)
+ * @param conn   acquired connection
+ * @param server current server record
+ * @param max_blank_lines how many blank lines to consume,
+ *                        or zero for none (considered data)
+ * @param flags  PROXY_CHECK_* bitmask
+ * @return APR_SUCCESS: connection established,
+ *         APR_ENOTEMPTY: connection established with data,
+ *         APR_ENOSOCKET: not connected,
+ *         APR_EINVAL: worker in error state (unusable),
+ *         other: connection closed/aborted (remotely)
  */
-PROXY_DECLARE(apr_status_t) ap_proxy_check_backend(const char *proxy_function,
-                                                   proxy_conn_rec *conn,
-                                                   server_rec *s,
-                                                   int expect_empty);
+PROXY_DECLARE(apr_status_t) ap_proxy_check_connection(const char *scheme,
+                                                      proxy_conn_rec *conn,
+                                                      server_rec *server,
+                                                      unsigned max_blank_lines,
+                                                      int flags);
 
 /**
  * Make a connection to the backend
index b8e818adb2c7cdc5fd5d281a5535ca90a6e14bf0..a31afa9b1abc037b5ee7dd1068424c9444c13518 100644 (file)
@@ -783,8 +783,10 @@ static int proxy_ajp_handler(request_rec *r, proxy_worker *worker,
             break;
 
         /* Step Two: Make the Connection */
-        if (ap_proxy_check_backend(scheme, backend, r->server, 1) &&
-                ap_proxy_connect_backend(scheme, backend, worker, r->server)) {
+        if (ap_proxy_check_connection(scheme, backend, r->server, 0,
+                                      PROXY_CHECK_CONN_EMPTY)
+                && ap_proxy_connect_backend(scheme, backend, worker,
+                                            r->server)) {
             ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(00896)
                           "failed to make connection to backend: %s",
                           backend->hostname);
index 2a760fcb0255c74398215d97e2424ae3f9661ec6..90b1c7d895c24422b9ec970913afbedf6bef4167 100644 (file)
@@ -949,10 +949,10 @@ static int proxy_fcgi_handler(request_rec *r, proxy_worker *worker,
     }
 
     /* Step Two: Make the Connection */
-    if ((backend->close || ap_proxy_check_backend(FCGI_SCHEME, backend,
-                                                  r->server, 1)) &&
-            ap_proxy_connect_backend(FCGI_SCHEME, backend, worker,
-                                     r->server)) {
+    if (ap_proxy_check_connection(FCGI_SCHEME, backend, r->server, 0,
+                                  PROXY_CHECK_CONN_EMPTY)
+            && ap_proxy_connect_backend(FCGI_SCHEME, backend, worker,
+                                        r->server)) {
         ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01079)
                       "failed to make connection to backend: %s",
                       backend->hostname);
index f5731652bf8f858bc011d84672412c48a23a8f14..ae6384424c167419aba148209c0848b1d0575164 100644 (file)
@@ -2068,9 +2068,10 @@ static int proxy_http_handler(request_rec *r, proxy_worker *worker,
         }
 
         /* Step Two: Make the Connection */
-        if (ap_proxy_check_backend(proxy_function, backend, r->server, 1) &&
-                ap_proxy_connect_backend(proxy_function, backend, worker,
-                                         r->server)) {
+        if (ap_proxy_check_connection(proxy_function, backend, r->server, 1,
+                                      PROXY_CHECK_CONN_EMPTY)
+                && ap_proxy_connect_backend(proxy_function, backend, worker,
+                                            r->server)) {
             ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01114)
                           "HTTP: failed to make connection to backend: %s",
                           backend->hostname);
index 00bac1e3070df3fd7792811c13f0fb5a3b02914e..481b05e5fb88d2576d8c3d9812a2f957b3fa1cc9 100644 (file)
@@ -2699,10 +2699,11 @@ PROXY_DECLARE(apr_status_t) ap_proxy_connect_uds(apr_socket_t *sock,
 #endif
 }
 
-PROXY_DECLARE(apr_status_t) ap_proxy_check_backend(const char *proxy_function,
-                                                   proxy_conn_rec *conn,
-                                                   server_rec *s,
-                                                   int expect_empty)
+PROXY_DECLARE(apr_status_t) ap_proxy_check_connection(const char *scheme,
+                                                      proxy_conn_rec *conn,
+                                                      server_rec *server,
+                                                      unsigned max_blank_lines,
+                                                      int flags)
 {
     apr_status_t rv = APR_SUCCESS;
     proxy_worker *worker = conn->worker;
@@ -2713,38 +2714,58 @@ PROXY_DECLARE(apr_status_t) ap_proxy_check_backend(const char *proxy_function,
          * e.g. for a timeout or bad status. We should respect this and should
          * not continue with a connection via this worker even if we got one.
          */
-        rv = APR_NOTFOUND;
-    }
-    else if (!conn->sock) {
-        rv = APR_ENOTSOCK;
+        rv = APR_EINVAL;
     }
     else if (conn->connection) {
-        conn_rec *c = conn->connection;
-        rv = ap_get_brigade(c->input_filters, conn->tmp_bb,
-                            AP_MODE_SPECULATIVE, APR_NONBLOCK_READ, 1);
-        if (APR_STATUS_IS_EAGAIN(rv)) {
-            rv = APR_SUCCESS;
-        }
-        else if (rv == APR_SUCCESS && expect_empty) {
-            apr_off_t len = 0;
-            apr_brigade_length(conn->tmp_bb, 0, &len);
-            if (len) {
+        /* We have a conn_rec, check the full filter stack for things like
+         * SSL alert/shutdown, filters aside data...
+         */
+        rv = ap_check_pipeline(conn->connection, conn->tmp_bb,
+                               max_blank_lines);
+        apr_brigade_cleanup(conn->tmp_bb);
+        if (rv == APR_SUCCESS) {
+            /* Some data available, the caller might not want them. */
+            if (flags & PROXY_CHECK_CONN_EMPTY) {
                 rv = APR_ENOTEMPTY;
             }
         }
-        apr_brigade_cleanup(conn->tmp_bb);
+        else if (APR_STATUS_IS_EAGAIN(rv)) {
+            /* Filter chain is OK and empty, yet we can't determine from
+             * ap_check_pipeline (actually ap_core_input_filter) whether
+             * an empty non-blocking read is EAGAIN or EOF on the socket
+             * side (it's always SUCCESS), so check it explicitely here.
+             */
+            if (ap_proxy_is_socket_connected(conn->sock)) {
+                rv = APR_SUCCESS;
+            }
+            else {
+                rv = APR_EPIPE;
+            }
+        }
     }
-    else if (!ap_proxy_is_socket_connected(conn->sock)) {
-        rv = APR_EPIPE;
+    else if (conn->sock) {
+        /* For modules working with sockets directly, check it. */
+        if (!ap_proxy_is_socket_connected(conn->sock)) {
+            rv = APR_EPIPE;
+        }
+    }
+    else {
+        rv = APR_ENOSOCKET;
     }
 
-    if (rv != APR_SUCCESS && conn->sock) {
+    if (rv == APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_TRACE2, 0, server,
+                     "%s: reusing backend connection %pI<>%pI",
+                     scheme, conn->connection->local_addr,
+                     conn->connection->client_addr);
+    }
+    else if (conn->sock) {
         /* This clears conn->scpool (and associated data), so backup and
          * restore any ssl_hostname for this connection set earlier by
          * ap_proxy_determine_connection().
          */
         char ssl_hostname[PROXY_WORKER_RFC1035_NAME_SIZE];
-        if (rv == APR_NOTFOUND
+        if (rv == APR_EINVAL
                 || !conn->ssl_hostname
                 || PROXY_STRNCPY(ssl_hostname, conn->ssl_hostname)) {
             ssl_hostname[0] = '\0';
@@ -2752,14 +2773,13 @@ PROXY_DECLARE(apr_status_t) ap_proxy_check_backend(const char *proxy_function,
 
         socket_cleanup(conn);
         if (rv != APR_ENOTEMPTY) {
-            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00951)
-                         "%s: backend socket is disconnected.",
-                         proxy_function);
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, server, APLOGNO(00951)
+                         "%s: backend socket is disconnected.", scheme);
         }
         else {
-            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(03408)
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, server, APLOGNO(03408)
                          "%s: reusable backend connection is not empty: "
-                         "forcibly closed", proxy_function);
+                         "forcibly closed", scheme);
         }
 
         if (ssl_hostname[0]) {
@@ -2785,8 +2805,8 @@ PROXY_DECLARE(int) ap_proxy_connect_backend(const char *proxy_function,
     proxy_server_conf *conf =
         (proxy_server_conf *) ap_get_module_config(sconf, &proxy_module);
 
-    rv = ap_proxy_check_backend(proxy_function, conn, s, 0);
-    if (rv == APR_NOTFOUND) {
+    rv = ap_proxy_check_connection(proxy_function, conn, s, 0, 0);
+    if (rv == APR_EINVAL) {
         return DECLINED;
     }
 
@@ -3002,7 +3022,7 @@ PROXY_DECLARE(int) ap_proxy_connect_backend(const char *proxy_function,
         if (rv == APR_SUCCESS) {
             socket_cleanup(conn);
         }
-        rv = APR_NOTFOUND;
+        rv = APR_EINVAL;
     }
 
     return rv == APR_SUCCESS ? OK : DECLINED;