Implement basic connection teardown
I finally understand the codebase again. It's rather complicated.
This commit is contained in:
parent
efd500ca3c
commit
a3ec0942f8
GPG Key ID:
A0420B94F92B9493
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@ -47,10 +47,10 @@ enum { PIPE_READ, PIPE_WRITE };
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#define FIND_CONTAINER(name, pointer, type, member) \
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type *name = CONTAINER_OF (pointer, type, member)
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// --- libev helpers -----------------------------------------------------------
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// --- Utilities ---------------------------------------------------------------
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static bool
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flush_queue (struct write_queue *queue, ev_io *watcher)
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flush_queue (struct write_queue *queue, int fd)
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{
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struct iovec vec[queue->len], *vec_iter = vec;
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LIST_FOR_EACH (struct write_req, iter, queue->head)
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@ -58,24 +58,17 @@ flush_queue (struct write_queue *queue, ev_io *watcher)
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ssize_t written;
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again:
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written = writev (watcher->fd, vec, N_ELEMENTS (vec));
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if (written < 0)
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if ((written = writev (fd, vec, N_ELEMENTS (vec))) >= 0)
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{
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if (errno == EAGAIN)
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goto skip;
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write_queue_processed (queue, written);
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return true;
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}
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if (errno == EINTR)
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goto again;
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return false;
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}
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write_queue_processed (queue, written);
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skip:
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if (write_queue_is_empty (queue))
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ev_io_stop (EV_DEFAULT_ watcher);
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else
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ev_io_start (EV_DEFAULT_ watcher);
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if (errno == EAGAIN)
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return true;
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return false;
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}
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// --- Logging -----------------------------------------------------------------
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@ -135,16 +128,17 @@ struct fcgi_muxer
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/// Write data to the underlying transport
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void (*write_cb) (struct fcgi_muxer *, const void *data, size_t len);
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/// Close the underlying transport
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// TODO: consider half-close and the subsequent handling
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/// Close the underlying transport. You are allowed to destroy the muxer
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/// directly from within the callback.
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void (*close_cb) (struct fcgi_muxer *);
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/// Start processing a request. Return false if no further action is
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/// to be done and the request should be finished.
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bool (*request_start_cb) (struct fcgi_muxer *, struct fcgi_request *);
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bool (*request_start_cb) (struct fcgi_request *);
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/// Handle incoming data. "len == 0" means EOF.
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void (*request_push_cb)
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/// Handle incoming data. "len == 0" means EOF. Returns false if
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/// the underlying transport should be closed, this being the last request.
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bool (*request_push_cb)
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(struct fcgi_request *, const void *data, size_t len);
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/// Destroy the handler's data stored in the request object
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@ -230,7 +224,7 @@ fcgi_request_push_params
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{
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// TODO: probably check the state of the header parser
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// TODO: request_start() can return false, end the request here?
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(void) self->muxer->request_start_cb (self->muxer, self);
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(void) self->muxer->request_start_cb (self);
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self->state = FCGI_REQUEST_STDIN;
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}
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}
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@ -282,7 +276,9 @@ fcgi_request_write (struct fcgi_request *self, const void *data, size_t len)
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}
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}
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static void
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/// Mark the request as done. Returns false if the underlying transport
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/// should be closed, this being the last request.
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static bool
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fcgi_request_finish (struct fcgi_request *self)
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{
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fcgi_request_flush (self);
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@ -292,14 +288,26 @@ fcgi_request_finish (struct fcgi_request *self)
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0 /* TODO app_status, although ignored */,
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FCGI_REQUEST_COMPLETE /* TODO protocol_status, may be different */);
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if (!(self->flags & FCGI_KEEP_CONN))
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{
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// TODO: tear down (shut down) the connection
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}
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bool should_close = !(self->flags & FCGI_KEEP_CONN);
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self->muxer->active_requests--;
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self->muxer->requests[self->request_id] = NULL;
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fcgi_request_destroy (self);
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// TODO: tear down (shut down) the connection. This is called from:
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//
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// 1. client_fcgi_request_push <- request_push_cb
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// <- fcgi_request_push_stdin <- fcgi_muxer_on_stdin
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// <- fcgi_muxer_on_message <- fcgi_parser_push <- fcgi_muxer_push
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// <- client_fcgi_push <- client_read_loop
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// => in this case no close_cb may be called
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// -> need to pass a false boolean aaall the way up,
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// then client_fcgi_finalize eventually cleans up the rest
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//
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// 2. client_fcgi_request_close_cb <- request_finish
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// => our direct caller must call fcgi_muxer::close_cb
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// -> not very nice to delegate it there
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return !should_close;
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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@ -418,6 +426,7 @@ fcgi_muxer_on_abort_request
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// TODO: abort the request: let it somehow produce FCGI_END_REQUEST,
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// make sure to send an stdout EOF record
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// TODO: and if that was not a FCGI_KEEP_CONN request, close the transport
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}
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static void
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@ -1841,23 +1850,24 @@ struct client
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{
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LIST_HEADER (struct client)
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// XXX: do we really need this here?
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struct server_context *ctx; ///< Server context
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struct client_vtable *vtable; ///< Client behaviour
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int socket_fd; ///< The TCP socket
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int socket_fd; ///< The network socket
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bool received_eof; ///< Whether EOF has been received yet
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bool closing; ///< Whether we're just flushing buffers
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bool half_closed; ///< Transport half-closed while closing
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struct write_queue write_queue; ///< Write queue
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ev_timer flush_timeout_watcher; ///< Write queue flush timer
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ev_io read_watcher; ///< The socket can be read from
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ev_io write_watcher; ///< The socket can be written to
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struct client_vtable *vtable; ///< Client behaviour
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};
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/// The concrete behaviour to serve a particular client's requests
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struct client_vtable
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{
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/// Process incoming data; "len == 0" means EOF.
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/// If the method returns false, the client is destroyed by caller.
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/// If the method returns false, client_close() is called by the caller.
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bool (*push) (struct client *client, const void *data, size_t len);
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// TODO: optional push_error() to inform about network I/O errors
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@ -1885,8 +1895,8 @@ client_write (struct client *self, const void *data, size_t len)
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static void
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client_destroy (struct client *self)
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{
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struct server_context *ctx = self->ctx;
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// XXX: this codebase halfway pretends there could be other contexts
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struct server_context *ctx = ev_userdata (EV_DEFAULT);
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LIST_UNLINK (ctx->clients, self);
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ctx->n_clients--;
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@ -1897,63 +1907,111 @@ client_destroy (struct client *self)
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ev_io_stop (EV_DEFAULT_ &self->write_watcher);
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xclose (self->socket_fd);
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write_queue_free (&self->write_queue);
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ev_timer_stop (EV_DEFAULT_ &self->flush_timeout_watcher);
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free (self);
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try_finish_quit (ctx);
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}
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/// Try to cleanly close the connection, waiting for the remote client to close
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/// its own side of the connection as a sign that it has processed all the data
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/// it wanted to. The client implementation will not receive any further data.
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/// May directly call client_destroy().
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static void
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client_close (struct client *self)
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{
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if (self->closing)
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return;
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self->closing = true;
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ev_timer_start (EV_DEFAULT_ &self->flush_timeout_watcher);
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ev_feed_event (EV_DEFAULT_ &self->write_watcher, EV_WRITE);
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// We assume the remote client doesn't want our data if it half-closes
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if (self->received_eof)
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client_destroy (self);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static bool
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client_read_loop (EV_P_ struct client *client, ev_io *watcher)
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{
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char buf[8192];
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while (true)
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ssize_t n_read;
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again:
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while ((n_read = recv (watcher->fd, buf, sizeof buf, 0)) >= 0)
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{
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ssize_t n_read = recv (watcher->fd, buf, sizeof buf, 0);
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if (n_read >= 0)
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{
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if (!client->vtable->push (client, buf, n_read))
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return false;
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if (!n_read)
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break;
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{
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// Don't deliver the EOF condition repeatedly
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ev_io_stop (EV_A_ watcher);
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client->received_eof = true;
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}
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else if (errno == EAGAIN)
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return true;
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else if (errno != EINTR)
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if (!client->closing
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&& !client->vtable->push (client, buf, n_read))
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{
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client_close (client);
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return false;
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}
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// Don't receive the EOF condition repeatedly
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ev_io_stop (EV_A_ watcher);
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// We can probably still write, so let's just return
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// XXX: if there's nothing to be written, shouldn't we close the connection?
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if (!n_read)
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return true;
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}
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if (errno == EINTR)
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goto again;
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if (errno == EAGAIN)
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return true;
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client_destroy (client);
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return false;
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}
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static void
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on_client_ready (EV_P_ ev_io *watcher, int revents)
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on_client_readable (EV_P_ ev_io *watcher, int revents)
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{
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struct client *client = watcher->data;
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// XXX: although read and write are in a sequence, if we create response
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// data, we'll still likely need to go back to the event loop.
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(void) revents;
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if (client_read_loop (EV_A_ client, watcher)
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&& client->closing && client->received_eof)
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client_destroy (client);
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}
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static void
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on_client_writable (EV_P_ ev_io *watcher, int revents)
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{
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struct client *client = watcher->data;
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(void) loop;
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(void) revents;
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if (revents & EV_READ)
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if (!client_read_loop (EV_A_ client, watcher))
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goto close;
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if (revents & EV_WRITE)
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// TODO: add "closing link" functionality -> automatic shutdown
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// (half-close) once we manage to flush the write buffer,
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// which is logically followed by waiting for an EOF from the client
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// TODO: some sort of "on_buffers_flushed" callback for streaming huge
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// chunks of external (or generated) data.
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if (!flush_queue (&client->write_queue, watcher))
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goto close;
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// chunks of external (or generated) data. That will need to be
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// forwarded to "struct request_handler".
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if (!flush_queue (&client->write_queue, watcher->fd))
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{
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client_destroy (client);
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return;
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}
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if (!write_queue_is_empty (&client->write_queue))
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return;
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close:
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ev_io_stop (EV_A_ watcher);
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if (client->closing && !client->half_closed)
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{
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if (!shutdown (client->socket_fd, SHUT_WR))
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client->half_closed = true;
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else
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client_destroy (client);
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}
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}
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static void
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on_client_timeout (EV_P_ ev_timer *watcher, int revents)
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{
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(void) loop;
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(void) revents;
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client_destroy (watcher->data);
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}
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/// Create a new instance of a subclass with the given size.
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@ -1964,14 +2022,15 @@ client_new (EV_P_ size_t size, int sock_fd)
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struct server_context *ctx = ev_userdata (loop);
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struct client *self = xcalloc (1, size);
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self->ctx = ctx;
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self->write_queue = write_queue_make ();
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ev_timer_init (&self->flush_timeout_watcher, on_client_timeout, 5., 0.);
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self->flush_timeout_watcher.data = self;
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set_blocking (sock_fd, false);
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self->socket_fd = sock_fd;
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ev_io_init (&self->read_watcher, on_client_ready, sock_fd, EV_READ);
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ev_io_init (&self->write_watcher, on_client_ready, sock_fd, EV_WRITE);
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ev_io_init (&self->read_watcher, on_client_readable, sock_fd, EV_READ);
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ev_io_init (&self->write_watcher, on_client_writable, sock_fd, EV_WRITE);
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self->read_watcher.data = self;
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self->write_watcher.data = self;
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@ -2010,37 +2069,36 @@ static void
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client_fcgi_request_close_cb (struct request *req)
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{
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FIND_CONTAINER (self, req, struct client_fcgi_request, request);
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// No more data to send, terminate the substream/request
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// XXX: this will most probably end up with client_fcgi_request_destroy(),
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// we might or might not need to defer this action
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fcgi_request_finish (self->fcgi_request);
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struct fcgi_muxer *muxer = self->fcgi_request->muxer;
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// No more data to send, terminate the substream/request,
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// and also the transport if the client didn't specifically ask to keep it
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if (!fcgi_request_finish (self->fcgi_request))
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muxer->close_cb (muxer);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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static bool
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client_fcgi_request_start
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(struct fcgi_muxer *mux, struct fcgi_request *fcgi_request)
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client_fcgi_request_start (struct fcgi_request *fcgi_request)
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{
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FIND_CONTAINER (self, mux, struct client_fcgi, muxer);
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struct client_fcgi_request *request =
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fcgi_request->handler_data = xcalloc (1, sizeof *request);
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request->fcgi_request = fcgi_request;
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request_init (&request->request);
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request->request.ctx = self->client.ctx;
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request->request.ctx = ev_userdata (EV_DEFAULT);
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request->request.write_cb = client_fcgi_request_write_cb;
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request->request.close_cb = client_fcgi_request_close_cb;
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return request_start (&request->request, &fcgi_request->headers);
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}
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static void
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static bool
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client_fcgi_request_push
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(struct fcgi_request *req, const void *data, size_t len)
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{
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struct client_fcgi_request *request = req->handler_data;
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request_push (&request->request, data, len);
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return request_push (&request->request, data, len)
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|| fcgi_request_finish (req);
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}
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static void
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@ -2064,9 +2122,7 @@ static void
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client_fcgi_close_cb (struct fcgi_muxer *mux)
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{
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FIND_CONTAINER (self, mux, struct client_fcgi, muxer);
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// FIXME: we should probably call something like client_shutdown(),
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// which may have an argument whether we should really use close()
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client_destroy (&self->client);
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client_close (&self->client);
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}
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// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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@ -2137,11 +2193,9 @@ client_scgi_write_cb (struct request *req, const void *data, size_t len)
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static void
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client_scgi_close_cb (struct request *req)
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{
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// NOTE: this rather really means "close me [the request]"
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FIND_CONTAINER (self, req, struct client_scgi, request);
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// FIXME: we should probably call something like client_shutdown(),
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// which may have an argument whether we should really use close()
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client_destroy (&self->client);
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// NOTE: this rather really means "close me [the request]"
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client_close (&self->client);
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}
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static bool
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@ -2201,7 +2255,6 @@ client_scgi_create (EV_P_ int sock_fd)
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self->client.vtable = &client_scgi_vtable;
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request_init (&self->request);
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self->request.ctx = self->client.ctx;
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self->request.write_cb = client_scgi_write_cb;
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self->request.close_cb = client_scgi_close_cb;
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@ -2231,8 +2284,9 @@ client_ws_on_message (struct ws_handler *handler,
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return false;
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}
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struct server_context *ctx = ev_userdata (EV_DEFAULT);
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struct str response = str_make ();
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process_json_rpc (self->client.ctx, data, len, &response);
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process_json_rpc (ctx, data, len, &response);
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if (response.len)
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ws_handler_send (&self->handler,
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WS_OPCODE_TEXT, response.str, response.len);
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