diff --git a/changelog b/changelog
index 97c0f647..f0278dc9 100644
--- a/changelog
+++ b/changelog
@@ -23,6 +23,11 @@ User api changes
LWS_CALLBACK_FILTER_NETWORK_CONNECTION also has the socket descriptor
delivered by @in now instead of @user.
+ - libwebsocket_write() now returns -1 for error, or the amount of data
+ actually accepted for send. Under load, the OS may signal it is
+ ready to send new data on the socket, but have only a restricted
+ amount of memory to buffer the packet compared to usual.
+
User api removal
----------------
diff --git a/lib/client-parser.c b/lib/client-parser.c
index 4125efd9..e548b4f0 100644
--- a/lib/client-parser.c
+++ b/lib/client-parser.c
@@ -273,7 +273,11 @@ spill:
}
lwsl_parser("client sees server close len = %d\n",
wsi->u.ws.rx_user_buffer_head);
- /* parrot the close packet payload back */
+ /*
+ * parrot the close packet payload back
+ * we do not care about how it went, we are closing
+ * immediately afterwards
+ */
libwebsocket_write(wsi, (unsigned char *)
&wsi->u.ws.rx_user_buffer[
LWS_SEND_BUFFER_PRE_PADDING],
@@ -284,7 +288,11 @@ spill:
case LWS_WS_OPCODE_07__PING:
lwsl_info("client received ping, doing pong\n");
- /* parrot the ping packet payload back as a pong*/
+ /*
+ * parrot the ping packet payload back as a pong
+ * !!! this may block or have partial write or fail
+ * !!! very unlikely if the ping size is small
+ */
libwebsocket_write(wsi, (unsigned char *)
&wsi->u.ws.rx_user_buffer[
LWS_SEND_BUFFER_PRE_PADDING],
diff --git a/lib/libwebsockets.c b/lib/libwebsockets.c
index 7414fe74..0c85f0af 100644
--- a/lib/libwebsockets.c
+++ b/lib/libwebsockets.c
@@ -276,7 +276,7 @@ libwebsocket_close_and_free_session(struct libwebsocket_context *context,
if (eff_buf.token_len)
if (lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
- eff_buf.token_len)) {
+ eff_buf.token_len) != eff_buf.token_len) {
lwsl_debug("close: ext spill failed\n");
goto just_kill_connection;
}
@@ -305,7 +305,7 @@ libwebsocket_close_and_free_session(struct libwebsocket_context *context,
n = libwebsocket_write(wsi,
&buf[LWS_SEND_BUFFER_PRE_PADDING + 2],
0, LWS_WRITE_CLOSE);
- if (!n) {
+ if (n >= 0) {
/*
* we have sent a nice protocol level indication we
* now wish to close, we should not send anything more
@@ -698,9 +698,18 @@ lws_handle_POLLOUT_event(struct libwebsocket_context *context,
/* assuming they gave us something to send, send it */
if (eff_buf.token_len) {
- if (lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
- eff_buf.token_len))
+ n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
+ eff_buf.token_len);
+ if (n < 0)
return -1;
+ /*
+ * Keep amount spilled small to minimize chance of this
+ */
+ if (n != eff_buf.token_len) {
+ lwsl_err("Unable to spill ext %d vs %s\n",
+ eff_buf.token_len, n);
+ return -1;
+ }
} else
continue;
diff --git a/lib/output.c b/lib/output.c
index 35389c23..2d8c3694 100644
--- a/lib/output.c
+++ b/lib/output.c
@@ -90,6 +90,10 @@ void lwsl_hexdump(void *vbuf, size_t len)
#endif
+/*
+ * notice this returns number of bytes sent, or -1
+ */
+
int lws_issue_raw(struct libwebsocket *wsi, unsigned char *buf, size_t len)
{
struct libwebsocket_context *context = wsi->protocol->owning_server;
@@ -117,7 +121,7 @@ int lws_issue_raw(struct libwebsocket *wsi, unsigned char *buf, size_t len)
}
if (m) /* handled */ {
/* lwsl_ext("ext sent it\n"); */
- return 0;
+ return m;
}
}
#endif
@@ -146,14 +150,14 @@ int lws_issue_raw(struct libwebsocket *wsi, unsigned char *buf, size_t len)
#endif
n = send(wsi->sock, buf, len, MSG_NOSIGNAL);
lws_latency(context, wsi, "send lws_issue_raw", n, n == len);
- if (n != len) {
+ if (n < 0) {
lwsl_debug("ERROR writing len %d to skt %d\n", len, n);
return -1;
}
#ifdef LWS_OPENSSL_SUPPORT
}
#endif
- return 0;
+ return n;
}
#ifdef LWS_NO_EXTENSIONS
@@ -210,10 +214,21 @@ lws_issue_raw_ext_access(struct libwebsocket *wsi,
/* assuming they left us something to send, send it */
- if (eff_buf.token_len)
- if (lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
- eff_buf.token_len))
+ if (eff_buf.token_len) {
+ n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
+ eff_buf.token_len);
+ if (n < 0)
return -1;
+ /*
+ * Keep amount spilled small to minimize chance of this
+ */
+ if (n != eff_buf.token_len) {
+ lwsl_err("Unable to spill ext %d vs %s\n",
+ eff_buf.token_len, n);
+ return -1;
+ }
+
+ }
lwsl_parser("written %d bytes to client\n", eff_buf.token_len);
@@ -247,7 +262,7 @@ lws_issue_raw_ext_access(struct libwebsocket *wsi,
ret = 0;
}
- return 0;
+ return len;
}
#endif
@@ -274,6 +289,11 @@ lws_issue_raw_ext_access(struct libwebsocket *wsi,
* valid storage before and after buf as explained above. This scheme
* allows maximum efficiency of sending data and protocol in a single
* packet while not burdening the user code with any protocol knowledge.
+ *
+ * Return may be -1 for a fatal error needing connection close, or a
+ * positive number reflecting the amount of bytes actually sent. This
+ * can be less than the requested number of bytes due to OS memory
+ * pressure at any given time.
*/
int libwebsocket_write(struct libwebsocket *wsi, unsigned char *buf,
@@ -285,6 +305,7 @@ int libwebsocket_write(struct libwebsocket *wsi, unsigned char *buf,
int masked7 = wsi->mode == LWS_CONNMODE_WS_CLIENT;
unsigned char *dropmask = NULL;
unsigned char is_masked_bit = 0;
+ size_t orig_len = len;
#ifndef LWS_NO_EXTENSIONS
struct lws_tokens eff_buf;
int m;
@@ -423,7 +444,7 @@ int libwebsocket_write(struct libwebsocket *wsi, unsigned char *buf,
if (libwebsocket_0405_frame_mask_generate(wsi)) {
lwsl_err("lws_write: frame mask generation failed\n");
- return 1;
+ return -1;
}
/*
@@ -453,11 +474,8 @@ send_raw:
case LWS_WRITE_HTTP:
case LWS_WRITE_PONG:
case LWS_WRITE_PING:
- if (lws_issue_raw(wsi, (unsigned char *)buf - pre,
- len + pre + post))
- return -1;
-
- return 0;
+ return lws_issue_raw(wsi, (unsigned char *)buf - pre,
+ len + pre + post);
default:
break;
}
@@ -476,26 +494,36 @@ send_raw:
* callback returns 1 in case it wants to spill more buffers
*/
- return lws_issue_raw_ext_access(wsi, buf - pre, len + pre + post);
+ n = lws_issue_raw_ext_access(wsi, buf - pre, len + pre + post);
+ if (n < 0)
+ return n;
+
+ return orig_len - ((len - pre + post) -n );
}
int libwebsockets_serve_http_file_fragment(
struct libwebsocket_context *context, struct libwebsocket *wsi)
{
int ret = 0;
- int n;
+ int n, m;
while (!lws_send_pipe_choked(wsi)) {
n = read(wsi->u.http.fd, context->service_buffer,
sizeof(context->service_buffer));
if (n > 0) {
- libwebsocket_write(wsi, context->service_buffer, n,
+ m = libwebsocket_write(wsi, context->service_buffer, n,
LWS_WRITE_HTTP);
+ if (m < 0)
+ return -1;
+
wsi->u.http.filepos += n;
+ if (m != n)
+ /* adjust for what was not sent */
+ lseek(wsi->u.http.fd, m - n, SEEK_CUR);
}
if (n < 0)
- return 1; /* caller will close */
+ return -1; /* caller will close */
if (n < sizeof(context->service_buffer) ||
wsi->u.http.filepos == wsi->u.http.filelen) {
@@ -552,6 +580,7 @@ int libwebsockets_serve_http_file(struct libwebsocket_context *context,
"HTTP/1.0 400 Bad\x0d\x0aServer: libwebsockets\x0d\x0a\x0d\x0a"
);
wsi->u.http.fd = 0;
+ /* too small to care about partial, closing anyway */
libwebsocket_write(wsi, context->service_buffer,
p - context->service_buffer, LWS_WRITE_HTTP);
@@ -569,8 +598,10 @@ int libwebsockets_serve_http_file(struct libwebsocket_context *context,
ret = libwebsocket_write(wsi, context->service_buffer,
p - context->service_buffer, LWS_WRITE_HTTP);
- if (ret)
+ if (ret != (p - context->service_buffer)) {
+ lwsl_err("_write returned %d from %d\n", ret, (p - context->service_buffer));
return -1;
+ }
wsi->u.http.filepos = 0;
wsi->state = WSI_STATE_HTTP_ISSUING_FILE;
diff --git a/lib/parsers.c b/lib/parsers.c
index e6b0d241..804ec9e3 100644
--- a/lib/parsers.c
+++ b/lib/parsers.c
@@ -935,7 +935,7 @@ spill:
LWS_SEND_BUFFER_PRE_PADDING],
wsi->u.ws.rx_user_buffer_head,
LWS_WRITE_CLOSE);
- if (n)
+ if (n < 0)
lwsl_info("write of close ack failed %d\n", n);
wsi->state = WSI_STATE_RETURNED_CLOSE_ALREADY;
/* close the connection */
@@ -951,6 +951,8 @@ spill:
n = libwebsocket_write(wsi, (unsigned char *)
&wsi->u.ws.rx_user_buffer[LWS_SEND_BUFFER_PRE_PADDING],
wsi->u.ws.rx_user_buffer_head, LWS_WRITE_PONG);
+ if (n < 0)
+ return -1;
/* ... then just drop it */
wsi->u.ws.rx_user_buffer_head = 0;
return 0;
diff --git a/lib/server-handshake.c b/lib/server-handshake.c
index 75938fe9..53da4e7a 100644
--- a/lib/server-handshake.c
+++ b/lib/server-handshake.c
@@ -241,7 +241,7 @@ handshake_0405(struct libwebsocket_context *context, struct libwebsocket *wsi)
#endif
n = libwebsocket_write(wsi, (unsigned char *)response,
p - response, LWS_WRITE_HTTP);
- if (n < 0) {
+ if (n != (p - response)) {
lwsl_debug("handshake_0405: ERROR writing to socket\n");
goto bail;
}
diff --git a/libwebsockets-api-doc.html b/libwebsockets-api-doc.html
index a38145cd..e4ad60bb 100644
--- a/libwebsockets-api-doc.html
+++ b/libwebsockets-api-doc.html
@@ -438,6 +438,11 @@ In the case of sending using websocket protocol, be sure to allocate
valid storage before and after buf as explained above. This scheme
allows maximum efficiency of sending data and protocol in a single
packet while not burdening the user code with any protocol knowledge.
+
+Return may be -1 for a fatal error needing connection close, or a
+positive number reflecting the amount of bytes actually sent. This
+can be less than the requested number of bytes due to OS memory
+pressure at any given time.
libwebsockets_serve_http_file - Send a file back to the client using http
diff --git a/test-server/test-client.c b/test-server/test-client.c
index debd43a7..b602442d 100644
--- a/test-server/test-client.c
+++ b/test-server/test-client.c
@@ -150,9 +150,16 @@ callback_lws_mirror(struct libwebsocket_context *context,
(int)random() % 250,
(int)random() % 24);
- libwebsocket_write(wsi,
+ n = libwebsocket_write(wsi,
&buf[LWS_SEND_BUFFER_PRE_PADDING], l, opts | LWS_WRITE_TEXT);
+ if (n < 0)
+ return -1;
+ if (n < l) {
+ lwsl_err("Partial write LWS_CALLBACK_CLIENT_WRITEABLE\n");
+ return -1;
+ }
+
mirror_lifetime--;
if (!mirror_lifetime) {
fprintf(stderr, "closing mirror session\n");
diff --git a/test-server/test-echo.c b/test-server/test-echo.c
index e9ecf9eb..d86d4d0e 100644
--- a/test-server/test-echo.c
+++ b/test-server/test-echo.c
@@ -69,6 +69,10 @@ callback_echo(struct libwebsocket_context *context,
lwsl_err("ERROR %d writing to socket, hanging up\n", n);
return 1;
}
+ if (n < pss->len) {
+ lwsl_err("Partial write\n");
+ return -1;
+ }
break;
case LWS_CALLBACK_RECEIVE:
@@ -101,7 +105,11 @@ callback_echo(struct libwebsocket_context *context,
n = libwebsocket_write(wsi, &pss->buf[LWS_SEND_BUFFER_PRE_PADDING], pss->len, LWS_WRITE_TEXT);
if (n < 0) {
lwsl_err("ERROR %d writing to socket, hanging up\n", n);
- return 1;
+ return -1;
+ }
+ if (n < pss->len) {
+ lwsl_err("Partial write\n");
+ return -1;
}
break;
#endif
diff --git a/test-server/test-fraggle.c b/test-server/test-fraggle.c
index b517370e..01b0819a 100644
--- a/test-server/test-fraggle.c
+++ b/test-server/test-fraggle.c
@@ -175,6 +175,12 @@ callback_fraggle(struct libwebsocket_context *context,
psf->state = FRAGSTATE_POST_PAYLOAD_SUM;
n = libwebsocket_write(wsi, bp, chunk, write_mode);
+ if (n < 0)
+ return -1;
+ if (n < chunk) {
+ lwsl_err("Partial write\n");
+ return -1;
+ }
libwebsocket_callback_on_writable(context, wsi);
break;
@@ -192,6 +198,12 @@ callback_fraggle(struct libwebsocket_context *context,
n = libwebsocket_write(wsi, (unsigned char *)bp,
4, LWS_WRITE_BINARY);
+ if (n < 0)
+ return -1;
+ if (n < 4) {
+ lwsl_err("Partial write\n");
+ return -1;
+ }
psf->state = FRAGSTATE_START_MESSAGE;
diff --git a/test-server/test-ping.c b/test-server/test-ping.c
index 7cc2c2d5..098981cf 100644
--- a/test-server/test-ping.c
+++ b/test-server/test-ping.c
@@ -259,14 +259,21 @@ callback_lws_mirror(struct libwebsocket_context * this,
global_tx_count++;
if (use_mirror)
- libwebsocket_write(wsi,
+ n = libwebsocket_write(wsi,
&pingbuf[LWS_SEND_BUFFER_PRE_PADDING],
size, write_options | LWS_WRITE_BINARY);
else
- libwebsocket_write(wsi,
+ n = libwebsocket_write(wsi,
&pingbuf[LWS_SEND_BUFFER_PRE_PADDING],
size, write_options | LWS_WRITE_PING);
+ if (n < 0)
+ return -1;
+ if (n < size) {
+ lwsl_err("Partial write\n");
+ return -1;
+ }
+
if (flood &&
(psd->ping_index - psd->rx_count) < (screen_width - 1))
fprintf(stderr, ".");
diff --git a/test-server/test-server.c b/test-server/test-server.c
index ce2f61e3..b059f1c5 100644
--- a/test-server/test-server.c
+++ b/test-server/test-server.c
@@ -122,13 +122,12 @@ static int callback_http(struct libwebsocket_context *context,
char client_ip[128];
#endif
char buf[256];
- int n;
+ int n, m;
unsigned char *p;
static unsigned char buffer[4096];
struct stat stat_buf;
struct per_session_data__http *pss = (struct per_session_data__http *)user;
#ifdef EXTERNAL_POLL
- int m;
int fd = (int)(long)in;
#endif
@@ -166,6 +165,7 @@ static int callback_http(struct libwebsocket_context *context,
* send the http headers...
* this won't block since it's the first payload sent
* on the connection since it was established
+ * (too small for partial)
*/
n = libwebsocket_write(wsi, buffer,
@@ -223,10 +223,13 @@ static int callback_http(struct libwebsocket_context *context,
* because it's HTTP and not websocket, don't need to take
* care about pre and postamble
*/
- n = libwebsocket_write(wsi, buffer, n, LWS_WRITE_HTTP);
- if (n < 0)
+ m = libwebsocket_write(wsi, buffer, n, LWS_WRITE_HTTP);
+ if (m < 0)
/* write failed, close conn */
goto bail;
+ if (m != n)
+ /* partial write, adjust */
+ lseek(pss->fd, m - n, SEEK_CUR);
} while (!lws_send_pipe_choked(wsi));
libwebsocket_callback_on_writable(context, wsi);
@@ -383,6 +386,7 @@ callback_dumb_increment(struct libwebsocket_context *context,
case LWS_CALLBACK_SERVER_WRITEABLE:
n = sprintf((char *)p, "%d", pss->number++);
+ /* too small for partial */
n = libwebsocket_write(wsi, p, n, LWS_WRITE_TEXT);
if (n < 0) {
lwsl_err("ERROR %d writing to di socket\n", n);
@@ -479,6 +483,9 @@ callback_lws_mirror(struct libwebsocket_context *context,
lwsl_err("ERROR %d writing to mirror socket\n", n);
return -1;
}
+ if (n < ringbuffer[pss->ringbuffer_tail].len) {
+ lwsl_err("mirror partial write %d vs %d\n", n, ringbuffer[pss->ringbuffer_tail].len);
+ }
if (pss->ringbuffer_tail == (MAX_MESSAGE_QUEUE - 1))
pss->ringbuffer_tail = 0;