diff --git a/changelog b/changelog
index 97c0f647a28cf8fe10fc629959591e56c7bcdf81..f0278dc92cf511d6f177b06ab54e788d2e9d9f0d 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 4125efd93c998dd71830edaf6438695859005bcd..e548b4f0e48dbd3881d5c54c171e1d769c3e339c 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 7414fe746609996bcbbd988318b5717929f41ece..0c85f0af1391a9adb83b96d3e9f6fa79515a8db9 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 35389c236a2ad26208a6beb1c3c9d60843e22a8b..2d8c3694597351eeeec3413fd65dfe9897d8abd0 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 e6b0d24126895832c165e22658a84ce8db03939f..804ec9e315e5bd384c4864ac102147ef250bd7cf 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 75938fe915f1532f80c6cc28bd9b9954ad3afe42..53da4e7ad5a1e94b58c455f96a09dd007c72d716 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 a38145cd58e652c41b16c21d2f885b20b0308dfe..e4ad60bbfb4176087da89c6abf8ab3571b43a4ed 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.
+<p>
+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.
</blockquote>
<hr>
<h2>libwebsockets_serve_http_file - Send a file back to the client using http</h2>
diff --git a/test-server/test-client.c b/test-server/test-client.c
index debd43a7c3e7cd292c274f7e6a10c63980cf6c9f..b602442d1f27db2785e7e83795e7ec466e4c715c 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 e9ecf9ebef472dcb7ef6c5612367afa93b7901f4..d86d4d0eb29736d6e3c19ed314bdf3292201018b 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 b517370eb1dda18dbe623b1b544d91ead24db633..01b0819aeb6a9cd80e18c2dd8688a482c879fdbb 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 7cc2c2d5f2bb1621cbf07af2a79e0abed54b1345..098981cf7a8158378e07812fc388267e57c5d97b 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 ce2f61e3ed40f63ba3ec607c329981af3a41e274..b059f1c535f5cf723edffb41fdad7b8e71231dd8 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;