commit 9174eb844bb2a6a23e4fd18c78c5b9ca84a0072c
parent 26b63fcb861aaab53c5a16fe43e8830ab3a61a19
Author: Evgeny Grin (Karlson2k) <k2k@narod.ru>
Date: Thu, 2 Mar 2017 11:53:16 +0300
process_urh(): process all recv() before all send() to overcome limitations on some platforms
Diffstat:
1 file changed, 79 insertions(+), 61 deletions(-)
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
@@ -1201,7 +1201,16 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
connection->tls_read_ready = false;
}
- /* handle reading from TLS client and writing to application */
+ /* Some platforms (W32, possibly Darwin) may discard data in system buffers
+ * received by system but unread by recv() if remote side was disconnected
+ * and failed send() attempted (send() will always fail after remote disconnect
+ * was detected).
+ * So, before trying send() on any socket, recv() must be performed at first
+ * otherwise last part of incoming data may be lost. */
+
+ /*
+ * handle reading from remote TLS client
+ */
if ( ( (0 != (MHD_EPOLL_STATE_READ_READY & urh->app.celi)) ||
(connection->tls_read_ready) ) &&
(urh->in_buffer_used < urh->in_buffer_size) )
@@ -1236,67 +1245,10 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
urh->app.celi &= ~MHD_EPOLL_STATE_READ_READY;
}
}
- if ( (0 != (MHD_EPOLL_STATE_WRITE_READY & urh->mhd.celi)) &&
- (urh->in_buffer_used > 0) )
- {
- ssize_t res;
- size_t data_size;
-
- data_size = urh->in_buffer_used;
- if (data_size > MHD_SCKT_SEND_MAX_SIZE_)
- data_size = MHD_SCKT_SEND_MAX_SIZE_;
-
- res = MHD_send_ (urh->mhd.socket,
- urh->in_buffer,
- data_size);
- if (0 > res)
- {
- int err = MHD_socket_get_error_ ();
-
- if (MHD_SCKT_ERR_IS_EAGAIN_ (err))
- urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
- else if ( (! MHD_SCKT_ERR_IS_EINTR_ (err)) &&
- (! MHD_SCKT_ERR_IS_LOW_RESOURCES_(err)) )
- {
- /* persistent / unrecoverable error, treat as
- if connection was shut down. */
-#ifdef HAVE_MESSAGES
- MHD_DLOG (daemon,
- _("Failed to forward to application " MHD_UNSIGNED_LONG_LONG_PRINTF \
- " bytes of data received from remote side: %s\n"),
- (MHD_UNSIGNED_LONG_LONG) urh->in_buffer_used,
- MHD_socket_strerr_ (err));
-#endif
- /* Discard any data received form remote. */
- urh->in_buffer_used = 0;
- /* Do not try to push data to application. */
- urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
- /* Reading from remote client is not required anymore. */
- urh->in_buffer_size = 0;
- urh->app.celi &= ~MHD_EPOLL_STATE_READ_READY;
- connection->tls_read_ready = false;
- }
- }
- else
- {
- if (urh->in_buffer_used != res)
- {
- memmove (urh->in_buffer,
- &urh->in_buffer[res],
- urh->in_buffer_used - res);
- urh->in_buffer_used -= res;
- if (data_size > (size_t)res)
- urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
- }
- else
- {
- urh->in_buffer_used = 0;
- }
- }
- }
-
- /* handle reading from application and writing to HTTPS client */
+ /*
+ * handle reading from application
+ */
/* If application signaled MHD about socket closure then
* check for any pending data even if socket is not marked
* as 'ready' (signal may arrive after poll()/select()).
@@ -1356,6 +1308,10 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
}
}
+
+ /*
+ * handle writing to remote HTTPS client
+ */
if ( (0 != (MHD_EPOLL_STATE_WRITE_READY & urh->app.celi)) &&
(urh->out_buffer_used > 0) )
{
@@ -1410,6 +1366,68 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
}
}
+ /*
+ * handle writing to application
+ */
+ if ( (0 != (MHD_EPOLL_STATE_WRITE_READY & urh->mhd.celi)) &&
+ (urh->in_buffer_used > 0) )
+ {
+ ssize_t res;
+ size_t data_size;
+
+ data_size = urh->in_buffer_used;
+ if (data_size > MHD_SCKT_SEND_MAX_SIZE_)
+ data_size = MHD_SCKT_SEND_MAX_SIZE_;
+
+ res = MHD_send_ (urh->mhd.socket,
+ urh->in_buffer,
+ data_size);
+ if (0 > res)
+ {
+ int err = MHD_socket_get_error_ ();
+
+ if (MHD_SCKT_ERR_IS_EAGAIN_ (err))
+ urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
+ else if ( (! MHD_SCKT_ERR_IS_EINTR_ (err)) &&
+ (! MHD_SCKT_ERR_IS_LOW_RESOURCES_(err)) )
+ {
+ /* persistent / unrecoverable error, treat as
+ if connection was shut down. */
+#ifdef HAVE_MESSAGES
+ MHD_DLOG (daemon,
+ _("Failed to forward to application " MHD_UNSIGNED_LONG_LONG_PRINTF \
+ " bytes of data received from remote side: %s\n"),
+ (MHD_UNSIGNED_LONG_LONG) urh->in_buffer_used,
+ MHD_socket_strerr_ (err));
+#endif
+ /* Discard any data received form remote. */
+ urh->in_buffer_used = 0;
+ /* Do not try to push data to application. */
+ urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
+ /* Reading from remote client is not required anymore. */
+ urh->in_buffer_size = 0;
+ urh->app.celi &= ~MHD_EPOLL_STATE_READ_READY;
+ connection->tls_read_ready = false;
+ }
+ }
+ else
+ {
+ if (urh->in_buffer_used != res)
+ {
+ memmove (urh->in_buffer,
+ &urh->in_buffer[res],
+ urh->in_buffer_used - res);
+ urh->in_buffer_used -= res;
+ if (data_size > (size_t)res)
+ urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
+ }
+ else
+ {
+ urh->in_buffer_used = 0;
+ }
+ }
+ }
+
/* Check whether data is present in TLS buffers
* and incoming forward buffer have some space. */
if ( (connection->tls_read_ready) &&
