commit 1855c73cd340ae6273251728e8d6d500b2c1119b
parent 8dadd66ddef2d9320b0a60b9bf7881f42b127c93
Author: Evgeny Grin (Karlson2k) <k2k@narod.ru>
Date: Thu, 2 Mar 2017 22:17:11 +0300
Corrected monitor 'upgraded' sockets for errors, corrected handling of error and
streamlined forwarding processing logic.
Added some comments.
Diffstat:
2 files changed, 195 insertions(+), 118 deletions(-)
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
@@ -698,6 +698,8 @@ urh_to_fdset (struct MHD_UpgradeResponseHandle *urh,
const MHD_socket mhd_sckt = urh->mhd.socket;
bool res = true;
+ /* Do not add to 'es' only if socket is closed
+ * or not used anymore. */
if (MHD_INVALID_SOCKET != conn_sckt)
{
if ( (urh->in_buffer_used < urh->in_buffer_size) &&
@@ -712,7 +714,12 @@ urh_to_fdset (struct MHD_UpgradeResponseHandle *urh,
max_fd,
fd_setsize)) )
res = false;
- if (0 != urh->in_buffer_size)
+ /* Do not monitor again for errors if error was detected before as
+ * error state is remembered. */
+ if ((0 == urh->app.celi & MHD_EPOLL_STATE_ERROR) &&
+ ((0 != urh->in_buffer_size) ||
+ (0 != urh->out_buffer_size) ||
+ (0 != urh->out_buffer_used)))
MHD_add_to_fd_set_ (conn_sckt,
es,
max_fd,
@@ -732,7 +739,12 @@ urh_to_fdset (struct MHD_UpgradeResponseHandle *urh,
max_fd,
fd_setsize)) )
res = false;
- if (0 != urh->out_buffer_size)
+ /* Do not monitor again for errors if error was detected before as
+ * error state is remembered. */
+ if ((0 == urh->mhd.celi & MHD_EPOLL_STATE_ERROR) &&
+ ((0 != urh->out_buffer_size) ||
+ (0 != urh->in_buffer_size) ||
+ (0 != urh->in_buffer_used)))
MHD_add_to_fd_set_ (mhd_sckt,
es,
max_fd,
@@ -761,8 +773,9 @@ urh_from_fdset (struct MHD_UpgradeResponseHandle *urh,
const MHD_socket conn_sckt = urh->connection->socket_fd;
const MHD_socket mhd_sckt = urh->mhd.socket;
- urh->app.celi = MHD_EPOLL_STATE_UNREADY;
- urh->mhd.celi = MHD_EPOLL_STATE_UNREADY;
+ /* Reset read/write ready, preserve error state. */
+ urh->app.celi &= (~MHD_EPOLL_STATE_READ_READY && ~MHD_EPOLL_STATE_WRITE_READY);
+ urh->mhd.celi &= (~MHD_EPOLL_STATE_READ_READY && ~MHD_EPOLL_STATE_WRITE_READY);
if (MHD_INVALID_SOCKET != conn_sckt)
{
@@ -799,17 +812,31 @@ urh_update_pollfd(struct MHD_UpgradeResponseHandle *urh,
{
p[0].events = 0;
p[1].events = 0;
+
if (urh->in_buffer_used < urh->in_buffer_size)
- p[0].events |= POLLIN | MHD_POLL_EVENTS_ERR_DISC;
+ p[0].events |= POLLIN;
if (0 != urh->out_buffer_used)
- p[0].events |= POLLOUT | MHD_POLL_EVENTS_ERR_DISC;
- if (0 != urh->in_buffer_size)
+ p[0].events |= POLLOUT;
+
+ /* Do not monitor again for errors if error was detected before as
+ * error state is remembered. */
+ if ((0 == urh->app.celi & MHD_EPOLL_STATE_ERROR) &&
+ ((0 != urh->in_buffer_size) ||
+ (0 != urh->out_buffer_size) ||
+ (0 != urh->out_buffer_used)))
p[0].events |= MHD_POLL_EVENTS_ERR_DISC;
+
if (urh->out_buffer_used < urh->out_buffer_size)
- p[1].events |= POLLIN | MHD_POLL_EVENTS_ERR_DISC;
+ p[1].events |= POLLIN;
if (0 != urh->in_buffer_used)
- p[1].events |= POLLOUT | MHD_POLL_EVENTS_ERR_DISC;
- if (0 != urh->out_buffer_size)
+ p[1].events |= POLLOUT;
+
+ /* Do not monitor again for errors if error was detected before as
+ * error state is remembered. */
+ if ((0 == urh->mhd.celi & MHD_EPOLL_STATE_ERROR) &&
+ ((0 != urh->out_buffer_size) ||
+ (0 != urh->in_buffer_size) ||
+ (0 != urh->in_buffer_used)))
p[1].events |= MHD_POLL_EVENTS_ERR_DISC;
}
@@ -839,18 +866,26 @@ static void
urh_from_pollfd(struct MHD_UpgradeResponseHandle *urh,
struct pollfd p[2])
{
+ /* Reset read/write ready, preserve error state. */
+ urh->app.celi &= (~MHD_EPOLL_STATE_READ_READY && ~MHD_EPOLL_STATE_WRITE_READY);
+ urh->mhd.celi &= (~MHD_EPOLL_STATE_READ_READY && ~MHD_EPOLL_STATE_WRITE_READY);
+
if (0 != (p[0].revents & POLLIN))
urh->app.celi |= MHD_EPOLL_STATE_READ_READY;
if (0 != (p[0].revents & POLLOUT))
urh->app.celi |= MHD_EPOLL_STATE_WRITE_READY;
- if (0 != (p[0].revents & MHD_POLL_REVENTS_ERR_DISC))
+ if (0 != (p[0].revents & POLLHUP))
+ urh->app.celi |= MHD_EPOLL_STATE_READ_READY | MHD_EPOLL_STATE_WRITE_READY;
+ if (0 != (p[0].revents & MHD_POLL_REVENTS_ERRROR))
urh->app.celi |= MHD_EPOLL_STATE_ERROR;
if (0 != (p[1].revents & POLLIN))
urh->mhd.celi |= MHD_EPOLL_STATE_READ_READY;
if (0 != (p[1].revents & POLLOUT))
urh->mhd.celi |= MHD_EPOLL_STATE_WRITE_READY;
- if (0 != (p[1].revents & MHD_POLL_REVENTS_ERR_DISC))
+ if (0 != (p[1].revents & POLLHUP))
urh->mhd.celi |= MHD_EPOLL_STATE_ERROR;
+ if (0 != (p[1].revents & MHD_POLL_REVENTS_ERRROR))
+ urh->mhd.celi |= MHD_EPOLL_STATE_READ_READY | MHD_EPOLL_STATE_WRITE_READY;
}
#endif /* HTTPS_SUPPORT && UPGRADE_SUPPORT */
@@ -1165,6 +1200,8 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
* each time. */
struct MHD_Connection * const connection = urh->connection;
struct MHD_Daemon * const daemon = connection->daemon;
+ /* Prevent data races. */
+ bool was_closed;
if (daemon->shutdown)
{
/* Daemon shutting down, application will not receive any more data. */
@@ -1177,7 +1214,8 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
#endif
urh->was_closed = true;
}
- if (urh->was_closed)
+ was_closed = urh->was_closed;
+ if (was_closed)
{
/* Application was closed connections: no more data
* can be forwarded to application socket. */
@@ -1191,6 +1229,13 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
#endif
}
+ /* 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()).
+ * Socketpair for forwarding is always in non-blocking mode
+ * so no risk that recv() will block the thread. */
+ if (0 != urh->out_buffer_size)
+ urh->mhd.celi |= MHD_EPOLL_STATE_READ_READY;
/* Discard any data received form remote. */
urh->in_buffer_used = 0;
/* Do not try to push data to application. */
@@ -1201,13 +1246,19 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
connection->tls_read_ready = false;
}
- /* 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).
+ /* On some platforms (W32, possibly Darwin) failed send() (send() will always
+ * fail after remote disconnect was detected) may discard data in system
+ * buffers received by system but not yet read by recv().
* So, before trying send() on any socket, recv() must be performed at first
* otherwise last part of incoming data may be lost. */
+ /* If disconnect or error was detected - try to read from socket
+ * to dry data possibly pending is system buffers. */
+ if (0 != (MHD_EPOLL_STATE_ERROR & urh->app.celi))
+ urh->app.celi |= MHD_EPOLL_STATE_READ_READY;
+ if (0 != (MHD_EPOLL_STATE_ERROR & urh->mhd.celi))
+ urh->mhd.celi |= MHD_EPOLL_STATE_READ_READY;
+
/*
* handle reading from remote TLS client
*/
@@ -1226,9 +1277,7 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
res = gnutls_record_recv (connection->tls_session,
&urh->in_buffer[urh->in_buffer_used],
buf_size);
- if (GNUTLS_E_AGAIN == res)
- urh->app.celi &= ~MHD_EPOLL_STATE_READ_READY;
- else if (res > 0)
+ if (0 < res)
{
urh->in_buffer_used += res;
if (buf_size > (size_t)res)
@@ -1236,26 +1285,34 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
else if (0 < gnutls_record_check_pending (connection->tls_session))
connection->tls_read_ready = true;
}
- else if ( (0 >= res ) &&
- (GNUTLS_E_INTERRUPTED != res) )
+ else /* 0 >= res */
{
- /* Connection was shut down or got unrecoverable error.
- * Reading from remote client is not required anymore. */
+ if (GNUTLS_E_INTERRUPTED != res)
+ {
+ urh->app.celi &= ~MHD_EPOLL_STATE_READ_READY;
+ if (GNUTLS_E_AGAIN != res)
+ {
+ /* Unrecoverable error on socket was detected or
+ * socket was disconnected/shut down. */
+ /* Stop trying to read from this TLS socket. */
+ urh->in_buffer_size = 0;
+ }
+ }
+ }
+ if (MHD_EPOLL_STATE_ERROR ==
+ ((MHD_EPOLL_STATE_ERROR | MHD_EPOLL_STATE_READ_READY) & urh->app.celi))
+ {
+ /* Unrecoverable error on socket was detected and all
+ * pending data was read from system buffers. */
+ /* Stop trying to read from this TLS socket. */
urh->in_buffer_size = 0;
- urh->app.celi &= ~MHD_EPOLL_STATE_READ_READY;
}
}
/*
* 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()).
- * Socketpair for forwarding is always in non-blocking mode
- * so no risk that recv() will block the thread. */
- if ( ( (0 != (MHD_EPOLL_STATE_READ_READY & urh->mhd.celi)) ||
- (urh->was_closed) ) &&
+ if ( (0 != (MHD_EPOLL_STATE_READ_READY & urh->mhd.celi)) &&
(urh->out_buffer_used < urh->out_buffer_size) )
{
ssize_t res;
@@ -1268,44 +1325,41 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
res = MHD_recv_ (urh->mhd.socket,
&urh->out_buffer[urh->out_buffer_used],
buf_size);
- if (0 > res)
+ if (0 < res)
+ {
+ urh->out_buffer_used += res;
+ if (buf_size > (size_t)res)
+ urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
+ }
+ else /* 0 >= res */
{
- if (urh->was_closed)
+ const int err = MHD_socket_get_error_ ();
+ if ((0 == res) ||
+ ((! MHD_SCKT_ERR_IS_EINTR_ (err)) &&
+ (! MHD_SCKT_ERR_IS_LOW_RESOURCES_(err))))
{
- /* All data was received and application will not
- * forward any more data. */
- /* Do not try to pull data from application. */
- urh->out_buffer_size = 0;
urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
- }
- else
- {
- const int err = MHD_socket_get_error_ ();
- if (MHD_SCKT_ERR_IS_EAGAIN_ (err))
- urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
- else if ( (! MHD_SCKT_ERR_IS_EINTR_ (err)) &&
- (! MHD_SCKT_ERR_IS_LOW_RESOURCES_(err)) )
+ if ((0 == res) ||
+ (was_closed) ||
+ (0 != (MHD_EPOLL_STATE_ERROR & urh->mhd.celi)) ||
+ (! MHD_SCKT_ERR_IS_EAGAIN_ (err)))
{
- /* persistent / unrecoverable error, treat as
- if connection was shut down */
- /* Do not try to pull data from application. */
+ /* Socket disconnect/shutdown was detected;
+ * Application signaled about closure of 'upgraded' socket;
+ * or persistent / unrecoverable error. */
+ /* Do not try to pull more data from application. */
urh->out_buffer_size = 0;
- urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
}
}
}
- else
- {
- urh->out_buffer_used += res;
- if (buf_size > (size_t)res)
- urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
- }
- if (0 == res)
+ if ( (0 == (MHD_EPOLL_STATE_READ_READY & urh->mhd.celi)) &&
+ ( (0 != (MHD_EPOLL_STATE_ERROR & urh->mhd.celi)) ||
+ (was_closed) ) )
{
- /* Connection was shut down or got unrecoverable error.
- Do not try to pull data from application. */
+ /* Unrecoverable error on socket was detected and all
+ * pending data was read from system buffers. */
+ /* Do not try to pull more data from application. */
urh->out_buffer_size = 0;
- urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
}
}
@@ -1325,40 +1379,49 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
res = gnutls_record_send (connection->tls_session,
urh->out_buffer,
data_size);
- if (GNUTLS_E_AGAIN == res)
+ if (0 < res)
{
- urh->app.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
- }
- else if (res > 0)
- {
- if (urh->out_buffer_used != res)
+ const size_t next_out_buffer_used = urh->out_buffer_used - res;
+ if (0 != next_out_buffer_used)
{
memmove (urh->out_buffer,
&urh->out_buffer[res],
- urh->out_buffer_used - res);
- urh->out_buffer_used -= res;
+ next_out_buffer_used);
if (data_size > (size_t)res)
urh->app.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
}
- else
+ urh->out_buffer_used = next_out_buffer_used;
+ }
+ else /* 0 >= res */
+ {
+ if (GNUTLS_E_INTERRUPTED != res)
{
- urh->out_buffer_used = 0;
+ urh->app.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
+ if (GNUTLS_E_INTERRUPTED != res)
+ {
+ /* TLS connection shut down or
+ * persistent / unrecoverable error. */
+#ifdef HAVE_MESSAGES
+ MHD_DLOG (daemon,
+ _("Failed to forward to remote client " MHD_UNSIGNED_LONG_LONG_PRINTF \
+ " bytes of data received from application: %s\n"),
+ (MHD_UNSIGNED_LONG_LONG) urh->out_buffer_used,
+ gnutls_strerror(res));
+#endif
+ /* Discard any data unsent to remote. */
+ urh->out_buffer_used = 0;
+ /* Do not try to pull more data from application. */
+ urh->out_buffer_size = 0;
+ urh->mhd.celi &= ~MHD_EPOLL_STATE_READ_READY;
+ }
}
}
- else if (GNUTLS_E_INTERRUPTED != res)
+ if ( (0 == urh->out_buffer_used) &&
+ (0 != (MHD_EPOLL_STATE_ERROR & urh->app.celi)) )
{
- /* persistent / unrecoverable error, treat as
- if connection was shut down. */
-#ifdef HAVE_MESSAGES
- MHD_DLOG (daemon,
- _("Failed to forward to remote client " MHD_UNSIGNED_LONG_LONG_PRINTF \
- " bytes of data received from application: %s\n"),
- (MHD_UNSIGNED_LONG_LONG) urh->out_buffer_used,
- gnutls_strerror(res));
-#endif
- /* Discard any data unsent to remote. */
- urh->out_buffer_used = 0;
- /* Do not try to sent to remote anymore. */
+ /* Unrecoverable error on socket was detected and all
+ * pending data was sent to remote. */
+ /* Do not try to send to remote anymore. */
urh->app.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
/* Do not try to pull more data from application. */
urh->out_buffer_size = 0;
@@ -1370,7 +1433,7 @@ 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) )
+ (urh->in_buffer_used > 0) )
{
ssize_t res;
size_t data_size;
@@ -1382,50 +1445,56 @@ process_urh (struct MHD_UpgradeResponseHandle *urh)
res = MHD_send_ (urh->mhd.socket,
urh->in_buffer,
data_size);
- if (0 > res)
+ 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)
+ const size_t next_in_buffer_used = urh->in_buffer_used - res;
+ if (0 != next_in_buffer_used)
{
memmove (urh->in_buffer,
&urh->in_buffer[res],
- urh->in_buffer_used - res);
- urh->in_buffer_used -= res;
+ next_in_buffer_used);
if (data_size > (size_t)res)
urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
}
- else
+ urh->in_buffer_used = next_in_buffer_used;
+ }
+ else /* 0 >= res */
+ {
+ const int err = MHD_socket_get_error_ ();
+ if ( (! MHD_SCKT_ERR_IS_EINTR_ (err)) &&
+ (! MHD_SCKT_ERR_IS_LOW_RESOURCES_(err)) )
{
- urh->in_buffer_used = 0;
+ urh->mhd.celi &= ~MHD_EPOLL_STATE_WRITE_READY;
+ if (! MHD_SCKT_ERR_IS_EAGAIN_ (err))
+ {
+ /* Socketpair connection shut down or
+ * persistent / unrecoverable error. */
+#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;
+ /* 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;
+ }
}
}
+ if ( (0 !=urh->in_buffer_used) &&
+ (0 != (MHD_EPOLL_STATE_ERROR & urh->mhd.celi)) )
+ {
+ /* 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;
+ }
}
/* Check whether data is present in TLS buffers
@@ -3835,6 +3904,10 @@ run_epoll_for_upgrade (struct MHD_Daemon *daemon)
ueh->celi |= MHD_EPOLL_STATE_READ_READY;
if (0 != (events[i].events & EPOLLOUT))
ueh->celi |= MHD_EPOLL_STATE_WRITE_READY;
+ if (0 != (events[i].events & EPOLLHUP))
+ ueh->celi |= MHD_EPOLL_STATE_READ_READY | MHD_EPOLL_STATE_WRITE_READY;
+ if (0 != (events[i].events & (EPOLLERR | EPOLLPRI)))
+ ueh->celi |= MHD_EPOLL_STATE_ERROR;
process_urh (urh);
/* Finished forwarding? */
diff --git a/src/microhttpd/mhd_sockets.h b/src/microhttpd/mhd_sockets.h
@@ -369,6 +369,10 @@
* Note: Out-of-band data is treated as error. */
# define MHD_POLL_REVENTS_ERR_DISC \
(MHD_POLLPRI_OR_ZERO | MHD_POLLRDBAND_OR_ZERO | MHD_POLLNVAL_OR_ZERO | POLLERR | POLLHUP)
+/* MHD_POLL_REVENTS_ERRROR is 'revents' mask for errors.
+ * Note: Out-of-band data is treated as error. */
+# define MHD_POLL_REVENTS_ERRROR \
+ (MHD_POLLPRI_OR_ZERO | MHD_POLLRDBAND_OR_ZERO | MHD_POLLNVAL_OR_ZERO | POLLERR)
#endif /* HAVE_POLL */
#define MHD_SCKT_MISSING_ERR_CODE_ 31450
