incomplete commit, adding 2 new helper functions and more.

3 files changed, 333 insertions, 6 deletions

diff --git a/src/microhttpd/connection.c b/src/microhttpd/connection.c
index 1893de15..626adb42 100644
--- a/src/microhttpd/connection.c
+++ b/src/microhttpd/connection.c
@@ -3350,12 +3350,20 @@ MHD_connection_handle_write (struct MHD_Connection *connection)
       return;
     case MHD_CONNECTION_HEADERS_SENDING:
       /* TODO: Maybe use MHD_send_on_connection2_()?  */
+      /*
+      ret = MHD_send_on_connection2_ (struct MHD_Connection *connection,
+                                      const char *header,
+                                      size_t header_size,
+                                      const char *buffer,
+                                      size_t buffer_size);
+      */
       ret = MHD_send_on_connection_ (connection,
                                      &connection->write_buffer
                                      [connection->write_buffer_send_offset],
                                      connection->write_buffer_append_offset -
                                      connection->write_buffer_send_offset,
                                      MHD_SSO_MAY_CORK);
+
       if (ret < 0)
         {
           if (MHD_ERR_AGAIN_ == ret)
@@ -3392,7 +3400,8 @@ MHD_connection_handle_write (struct MHD_Connection *connection)
 #if defined(_MHD_HAVE_SENDFILE)
           if (MHD_resp_sender_sendfile == connection->resp_sender)
             {
-              ret = sendfile_adapter (connection);
+              // ret = sendfile_adapter (connection);
+              ret = MHD_sendfile_on_connection_ (connection);
             }
           else
 #else  /* ! _MHD_HAVE_SENDFILE */
diff --git a/src/microhttpd/mhd_send.c b/src/microhttpd/mhd_send.c
index 7991830c..ee32a868 100644
--- a/src/microhttpd/mhd_send.c
+++ b/src/microhttpd/mhd_send.c
@@ -33,6 +33,52 @@
 #include "mhd_send.h"
 
 /**
+ * Set socket to nodelay, on or off.
+ *
+ * @param connection the MHD_Connection structure
+ * @param value the state to set, boolean
+ */
+void
+MHD_send_socket_state_nodelay_ (struct MHD_Connection *connection,
+                                bool value)
+{
+#if TCP_NODELAY
+  const MHD_SCKT_OPT_BOOL_ state_val = value ? 1 : 0;
+
+  if (0 == setsockopt (connection->socket_fd,
+                       IPPROTO_TCP,
+                       TCP_NODELAY,
+                       (const void *) &state_val,
+                       sizeof (state_val)))
+    {
+      connection->sk_tcp_nodelay_on = value;
+    }
+#endif
+}
+
+void
+MHD_send_socket_state_nopush_ (struct MHD_Connection *connection,
+                               bool value,
+                               bool state_store)
+{
+#if TCP_NOPUSH
+  const MHD_SCKT_OPT_BOOL_ state_val = value ? 1 : 0;
+
+  if (0 == setsockopt (connection->socket_fd,
+                       IPPROTO_TCP,
+                       TCP_NOPUSH,
+                       (const void *) &state_val,
+                       sizeof (state_val)))
+    {
+      /* When TRUE above, this is usually FALSE, but
+       * not always. We can't use the negation of
+       * value for that reason. */
+      connection->sk_tcp_nodelay_on = state_store;
+    }
+#endif
+}
+
+/**
  * Send buffer on connection, and remember the current state of
  * the socket options; only call setsockopt when absolutely
  * necessary.
@@ -145,6 +191,8 @@ MHD_send_on_connection_ (struct MHD_Connection *connection,
    * exist and we can disregard TCP_NODELAY unless requested. */
   if ((! using_tls) && (use_corknopush) && (have_cork && ! want_cork))
     {
+      MHD_send_socket_state_nopush_ (connection, true, false);
+      /*
       if (0 == setsockopt (s,
                            IPPROTO_TCP,
                            TCP_NOPUSH,
@@ -153,11 +201,13 @@ MHD_send_on_connection_ (struct MHD_Connection *connection,
         {
           connection->sk_tcp_nodelay_on = false;
         }
+      */
     }
 #endif
 #if TCP_NODELAY
   if ((! using_tls) && (! use_corknopush) && (! have_cork && want_cork))
     {
+      /*
       if (0 == setsockopt (s,
                            IPPROTO_TCP,
                            TCP_NODELAY,
@@ -166,6 +216,8 @@ MHD_send_on_connection_ (struct MHD_Connection *connection,
       {
         connection->sk_tcp_nodelay_on = false;
       }
+      */
+      MHD_send_socket_state_nodelay_ (connection, false);
     }
 #endif
 
@@ -274,6 +326,8 @@ MHD_send_on_connection_ (struct MHD_Connection *connection,
    * for the TCP_CORK case here. */
   if ((! using_tls) && (use_corknopush) && (have_cork && ! want_cork))
   {
+    MHD_send_socket_state_nopush_ (connection, true, false);
+    /*
     if (0 == setsockopt (s,
                          IPPROTO_TCP,
                          TCP_NOPUSH,
@@ -282,12 +336,15 @@ MHD_send_on_connection_ (struct MHD_Connection *connection,
       {
         connection->sk_tcp_nodelay_on = false;
       }
+    */
   }
 #endif
 
 #if TCP_NODELAY
   if ((! using_tls) && (! use_corknopush) && (have_cork && ! want_cork))
     {
+      MHD_send_socket_state_nodelay_ (connection, true);
+      /*
       if (0 == setsockopt (s,
                            IPPROTO_TCP,
                            TCP_NODELAY,
@@ -296,6 +353,7 @@ MHD_send_on_connection_ (struct MHD_Connection *connection,
       {
         connection->sk_tcp_nodelay_on = true;
       }
+      */
     }
 #endif
 
@@ -348,6 +406,8 @@ MHD_send_on_connection2_ (struct MHD_Connection *connection,
 #if TCP_NODELAY
   if ((! use_corknopush) && (! have_cork && want_cork))
     {
+      MHD_send_socket_state_nodelay_ (connection, false);
+      /*
       if (0 == setsockopt (s,
                            IPPROTO_TCP,
                            TCP_NODELAY,
@@ -356,6 +416,7 @@ MHD_send_on_connection2_ (struct MHD_Connection *connection,
         {
           connection->sk_tcp_nodelay_on = false;
         }
+      */
     }
 #endif
 
@@ -404,6 +465,8 @@ MHD_send_on_connection2_ (struct MHD_Connection *connection,
       if (ret == header_len + buffer_len)
         {
           /* Response complete, set NOPUSH to off */
+          MHD_send_socket_state_nopush_ (connection, false, false);
+          /*
           if (0 == setsockopt (s,
                                IPPROTO_TCP,
                                TCP_NOPUSH,
@@ -412,6 +475,7 @@ MHD_send_on_connection2_ (struct MHD_Connection *connection,
             {
               connection->sk_tcp_nodelay_on = false;
             }
+          */
         }
       errno = eno;
     }
@@ -431,11 +495,262 @@ MHD_send_on_connection2_ (struct MHD_Connection *connection,
  * with this seems to be to mmap the file and write(2) as
  * large a chunk as possible to the socket. Alternatively,
  * use madvise(..., MADV_SEQUENTIAL). */
+
+#if defined(_MHD_HAVE_SENDFILE)
+/**
+ * Function for sending responses backed by file FD.
+ * A sendfile() wrapper which also performs cork/uncork
+ * operations.
+ *
+ * @param connection the #MHD_Connection structure
+ * @return actual number of bytes sent
+ */
 ssize_t
-MHD_sendfile_on_connection_ (struct MHD_Connection *connection,
-                             const char *buffer,
-                             size_t buffer_size,
-                             enum MHD_SendSocketOptions options)
+MHD_sendfile_on_connection_ (struct MHD_Connection *connection)
 {
-  // TODO
+  // I'm looking for a version of sendfile_adapter() that *also* performs
+  // cork/uncork operations. Specifically, we want to make sure that the
+  // buffer is flushed after sendfile() is done (so setsockopt() behavior
+  // equivalent to MHD_SSO_NO_CORK), and _also_ of course update the
+  // setsockopt state, i.e. connection->sk_tcp_nodelay_on = true;
+
+  bool want_cork = false;
+  bool have_cork;
+  bool have_more;
+  bool use_corknopush;
+  bool using_tls = false;
+  ssize_t ret;
+  const int file_fd = connection->response->fd;
+  uint64_t left;
+  uint64_t offsetu64;
+#ifndef HAVE_SENDFILE64
+  const uint64_t max_off_t = (uint64_t)OFF_T_MAX;
+#else  /* HAVE_SENDFILE64 */
+  const uint64_t max_off_t = (uint64_t)OFF64_T_MAX;
+#endif /* HAVE_SENDFILE64 */
+#ifdef MHD_LINUX_SOLARIS_SENDFILE
+#ifndef HAVE_SENDFILE64
+  off_t offset;
+#else  /* HAVE_SENDFILE64 */
+  off64_t offset;
+#endif /* HAVE_SENDFILE64 */
+#endif /* MHD_LINUX_SOLARIS_SENDFILE */
+#ifdef HAVE_FREEBSD_SENDFILE
+  off_t sent_bytes;
+  int flags = 0;
+#endif
+#ifdef HAVE_DARWIN_SENDFILE
+  off_t len;
+#endif /* HAVE_DARWIN_SENDFILE */
+  const bool used_thr_p_c = (0 != (connection->daemon->options & MHD_USE_THREAD_PER_CONNECTION));
+  const size_t chunk_size = used_thr_p_c ? MHD_SENFILE_CHUNK_THR_P_C_ : MHD_SENFILE_CHUNK_;
+  size_t send_size = 0;
+  mhd_assert (MHD_resp_sender_sendfile == connection->resp_sender);
+
+  offsetu64 = connection->response_write_position + connection->response->fd_off;
+  left = connection->response->total_size - connection->response_write_position;
+  /* Do not allow system to stick sending on single fast connection:
+   * use 128KiB chunks (2MiB for thread-per-connection). */
+  send_size = (left > chunk_size) ? chunk_size : (size_t) left;
+  if (max_off_t < offsetu64)
+    { /* Retry to send with standard 'send()'. */
+      connection->resp_sender = MHD_resp_sender_std;
+      return MHD_ERR_AGAIN_;
+    }
+#ifdef MHD_LINUX_SOLARIS_SENDFILE
+#ifndef HAVE_SENDFILE64
+  offset = (off_t) offsetu64;
+  ret = sendfile (connection->socket_fd,
+                  file_fd,
+                  &offset,
+                  send_size);
+#else  /* HAVE_SENDFILE64 */
+  offset = (off64_t) offsetu64;
+  ret = sendfile64 (connection->socket_fd,
+                    file_fd,
+                    &offset,
+                    send_size);
+#endif /* HAVE_SENDFILE64 */
+  if (0 > ret)
+    {
+      const int err = MHD_socket_get_error_();
+      if (MHD_SCKT_ERR_IS_EAGAIN_(err))
+        {
+#ifdef EPOLL_SUPPORT
+          /* EAGAIN --- no longer write-ready */
+          connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
+#endif /* EPOLL_SUPPORT */
+          return MHD_ERR_AGAIN_;
+        }
+      if (MHD_SCKT_ERR_IS_EINTR_ (err))
+        return MHD_ERR_AGAIN_;
+#ifdef HAVE_LINUX_SENDFILE
+      if (MHD_SCKT_ERR_IS_(err,
+                           MHD_SCKT_EBADF_))
+        return MHD_ERR_BADF_;
+      /* sendfile() failed with EINVAL if mmap()-like operations are not
+         supported for FD or other 'unusual' errors occurred, so we should try
+         to fall back to 'SEND'; see also this thread for info on
+         odd libc/Linux behavior with sendfile:
+         http://lists.gnu.org/archive/html/libmicrohttpd/2011-02/msg00015.html */
+      connection->resp_sender = MHD_resp_sender_std;
+      return MHD_ERR_AGAIN_;
+#else  /* HAVE_SOLARIS_SENDFILE */
+      if ( (EAFNOSUPPORT == err) ||
+           (EINVAL == err) ||
+           (EOPNOTSUPP == err) )
+        { /* Retry with standard file reader. */
+          connection->resp_sender = MHD_resp_sender_std;
+          return MHD_ERR_AGAIN_;
+        }
+      if ( (ENOTCONN == err) ||
+           (EPIPE == err) )
+        {
+          return MHD_ERR_CONNRESET_;
+        }
+      return MHD_ERR_BADF_; /* Fail hard */
+#endif /* HAVE_SOLARIS_SENDFILE */
+    }
+#ifdef EPOLL_SUPPORT
+  else if (send_size > (size_t)ret)
+        connection->epoll_state &= ~MHD_EPOLL_STATE_WRITE_READY;
+#endif /* EPOLL_SUPPORT */
+#elif defined(HAVE_FREEBSD_SENDFILE)
+#ifdef SF_FLAGS
+  flags = used_thr_p_c ?
+      freebsd_sendfile_flags_thd_p_c_ : freebsd_sendfile_flags_;
+#endif /* SF_FLAGS */
+  if (0 != sendfile (file_fd,
+                     connection->socket_fd,
+                     (off_t) offsetu64,
+                     send_size,
+                     NULL,
+                     &sent_bytes,
+                     flags))
+    {
+      const int err = MHD_socket_get_error_();
+      if (MHD_SCKT_ERR_IS_EAGAIN_(err) ||
+          MHD_SCKT_ERR_IS_EINTR_(err) ||
+          EBUSY == err)
+        {
+          mhd_assert (SSIZE_MAX >= sent_bytes);
+          if (0 != sent_bytes)
+            return (ssize_t)sent_bytes;
+
+          return MHD_ERR_AGAIN_;
+        }
+      /* Some unrecoverable error. Possibly file FD is not suitable
+       * for sendfile(). Retry with standard send(). */
+      connection->resp_sender = MHD_resp_sender_std;
+      return MHD_ERR_AGAIN_;
+    }
+  mhd_assert (0 < sent_bytes);
+  mhd_assert (SSIZE_MAX >= sent_bytes);
+  ret = (ssize_t)sent_bytes;
+#elif defined(HAVE_DARWIN_SENDFILE)
+  len = (off_t)send_size; /* chunk always fit */
+  if (0 != sendfile (file_fd,
+                     connection->socket_fd,
+                     (off_t) offsetu64,
+                     &len,
+                     NULL,
+                     0))
+    {
+      const int err = MHD_socket_get_error_();
+      if (MHD_SCKT_ERR_IS_EAGAIN_(err) ||
+          MHD_SCKT_ERR_IS_EINTR_(err))
+        {
+          mhd_assert (0 <= len);
+          mhd_assert (SSIZE_MAX >= len);
+          mhd_assert (send_size >= (size_t)len);
+          if (0 != len)
+            return (ssize_t)len;
+
+          return MHD_ERR_AGAIN_;
+        }
+      if (ENOTCONN == err ||
+          EPIPE == err)
+        return MHD_ERR_CONNRESET_;
+      if (ENOTSUP == err ||
+          EOPNOTSUPP == err)
+        { /* This file FD is not suitable for sendfile().
+           * Retry with standard send(). */
+          connection->resp_sender = MHD_resp_sender_std;
+          return MHD_ERR_AGAIN_;
+        }
+      return MHD_ERR_BADF_; /* Return hard error. */
+    }
+  mhd_assert (0 <= len);
+  mhd_assert (SSIZE_MAX >= len);
+  mhd_assert (send_size >= (size_t)len);
+  ret = (ssize_t)len;
+#endif /* HAVE_FREEBSD_SENDFILE */
+
+  /* ! could be avoided by redefining the variable. */
+  have_cork = ! connection->sk_tcp_nodelay_on;
+
+#ifdef MSG_MORE
+  have_more = true;
+#else
+  have_more = false;
+#endif
+
+#if TCP_NODELAY
+  use_corknopush = false;
+#elif TCP_CORK
+  use_corknopush = true;
+#elif TCP_NOPUSH
+  use_corknopush = true;
+#endif
+
+#ifdef HTTPS_SUPPORT
+  using_tls = (0 != (connection->daemon->options & MHD_USE_TLS));
+#endif
+
+#if TCP_CORK
+  /* When we have CORK, we can have NODELAY on the same system,
+   * at least since Linux 2.2 and both can be combined since
+   * Linux 2.5.71. For more details refer to tcp(7) on Linux.
+   * No other system in 2019-06 has TCP_CORK. */
+  if ((! using_tls) && (use_corknopush) && (have_cork && ! want_cork))
+    {
+      if (0 == setsockopt (connection->socket_fd,
+                           IPPROTO_TCP,
+                           TCP_CORK,
+                           (const void *) &off_val,
+                           sizeof (off_val)))
+      {
+        connection->sk_tcp_nodelay_on = true;
+      }
+      else if (0 == setsockopt (connection->socket_fd,
+                                IPPROTO_TCP,
+                                TCP_NODELAY,
+                                (const void *) &on_val,
+                                sizeof (on_val)))
+      {
+        connection->sk_tcp_nodelay_on = true;
+      }
+    }
+#elif TCP_NOPUSH
+  /* TCP_NOPUSH on FreeBSD is equal to cork on Linux, with the
+   * exception that we know that TCP_NOPUSH will definitely
+   * exist and we can disregard TCP_NODELAY unless requested. */
+  if ((! using_tls) && (use_corknopush) && (have_cork && ! want_cork))
+    {
+      MHD_send_socket_state_nopush_ (connection, true, false);
+      /*
+      if (0 == setsockopt (connection->socket_fd,
+                           IPPROTO_TCP,
+                           TCP_NOPUSH,
+                           (const void *) &on_val,
+                           sizeof (on_val)))
+        {
+          connection->sk_tcp_nodelay_on = false;
+        }
+      */
+    }
+#endif
+
+  return ret;
 }
+#endif /* _MHD_HAVE_SENDFILE */
diff --git a/src/microhttpd/mhd_send.h b/src/microhttpd/mhd_send.h
index e6ed3268..a6049865 100644
--- a/src/microhttpd/mhd_send.h
+++ b/src/microhttpd/mhd_send.h
@@ -74,4 +74,7 @@ MHD_send_on_connection2_ (struct MHD_Connection *connection,
                           size_t header_size,
                           const char *buffer,
                           size_t buffer_size);
+
+ssize_t
+MHD_sendfile_on_connection_ (struct MHD_Connection *connection);
 #endif /* MHD_SEND_H */