Implement write buffering for the ptys

If the receiving side of the pty is slow, the kernel pty buffer (of 4096
bytes) overflows and an unreported lossage occurs. This can be seen when
receiving a large SIM phonebook with busy frameworkd.

diff --git a/ChangeLog b/ChangeLog
index f8dfb116049dcb0d3cd8a9948a1637570f39b24b..5e1f25ad8a9d6b0dbc6e7e2d9779f0b0f4fc2652 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2009-01-10     Paul Fertser    <fercerpav@gmail.com>
+
+       * 0001-Implement-write-buffering-for-the-ptys.patch
+
 2008-12-06     Michael Lauer   <mickey@openmoko.org>
 
        * Release as 0.9.2.1

diff --git a/src/gsm0710muxd.c b/src/gsm0710muxd.c
index 083df5dbbe90b499e66ad91567eafc925a4a4014..cb8df03f3f4ecadb6fea305f0021c4524f2a4569 100644 (file)
--- a/src/gsm0710muxd.c
+++ b/src/gsm0710muxd.c
@@ -114,6 +114,7 @@ DBusConnection* dbus_g_connection_get_connection(DBusGConnection *gconnection);
 // enabled The value is in seconds
 #define GSM0710_POLLING_INTERVAL 5
 #define GSM0710_BUFFER_SIZE 2048
+#define PTY_GLIB_BUFFER_SIZE (16*1024)
 
 ////////////////////////////////////////////////////// types
 //
@@ -153,6 +154,7 @@ typedef struct Channel
        int remaining;
        unsigned char *tmp;
        guint g_source;
+       GIOChannel* g_channel;
 } Channel;
 
 typedef enum MuxerStates 
@@ -687,8 +689,10 @@ static gboolean c_alloc_channel(const char* origin, const char** name)
                                        SYSCHECK(unlockpt(channellist[i].fd));
                                }
                                channellist[i].v24_signals = GSM0710_SIGNAL_DV | GSM0710_SIGNAL_RTR | GSM0710_SIGNAL_RTC | GSM0710_EA;
-                               GIOChannel* g_channel = g_io_channel_unix_new(channellist[i].fd);
-                               channellist[i].g_source = g_io_add_watch(g_channel, G_IO_IN | G_IO_HUP, pseudo_device_read, channellist+i);
+                               channellist[i].g_channel = g_io_channel_unix_new(channellist[i].fd);
+                               g_io_channel_set_encoding(channellist[i].g_channel, NULL, NULL );
+                               g_io_channel_set_buffer_size( channellist[i].g_channel, PTY_GLIB_BUFFER_SIZE );
+                               channellist[i].g_source = g_io_add_watch(channellist[i].g_channel, G_IO_IN | G_IO_HUP, pseudo_device_read, channellist+i);
                                write_frame(i, NULL, 0, GSM0710_TYPE_SABM | GSM0710_PF);
                                LOG(LOG_INFO, "Connecting %s to virtual channel %d for %s on %s",
                                        channellist[i].ptsname, channellist[i].id, channellist[i].origin, serial.devicename);
@@ -1372,9 +1376,15 @@ int extract_frames(
                        LOG(LOG_DEBUG, "Frame is UI or UIH");
                        if (frame->channel > 0)
                        {
+                               gsize written;
                                LOG(LOG_DEBUG, "Frame channel > 0, pseudo channel");
 //data from logical channel
-                               write(channellist[frame->channel].fd, frame->data, frame->length);
+                               g_io_channel_write_chars(channellist[frame->channel].g_channel, (gchar*)frame->data, (gssize)frame->length, &written, NULL);
+                               if (written != frame->length)
+                                       LOG(LOG_WARNING, "Pty write buffer overflow, data loss: needed to write %d bytes, written %d, channel %d", frame->length, written, frame->channel);
+                               else
+                                       LOG(LOG_DEBUG, "Written %d bytes to pty channel %d", written, frame->channel);
+                               g_io_channel_flush(channellist[frame->channel].g_channel, NULL );
                        }
                        else
                        {
@@ -1740,6 +1750,7 @@ static int close_devices()
 
 static gboolean watchdog(gpointer data)
 {
+       int i;
        LOG(LOG_DEBUG, "Enter");
        Serial* serial = (Serial*)data;
        LOG(LOG_DEBUG, "Serial state is %d", serial->state);
@@ -1748,13 +1759,16 @@ static gboolean watchdog(gpointer data)
        case MUX_STATE_OPENING:
                if (open_serial_device(serial) < 0)
                        LOG(LOG_WARNING, "Could not open all devices and start muxer");
-               serial->g_source_watchdog = g_timeout_add_seconds(5, watchdog, data); // let the dog watch every 5 sec
+               serial->g_source_watchdog = g_timeout_add_seconds(1, watchdog, data); // let the dog watch every 1 sec
                LOG(LOG_INFO, "Watchdog started");
        case MUX_STATE_INITILIZING:
                if (start_muxer(serial) < 0)
                        LOG(LOG_WARNING, "Could not open all devices and start muxer errno=%d", errno);
        break;
        case MUX_STATE_MUXING:
+               for (i=1;i<GSM0710_MAX_CHANNELS;i++)
+                       if (channellist[i].fd >= 0)
+                               g_io_channel_flush(channellist[i].g_channel, NULL);
                if (use_ping)
                {
                        if (serial->ping_number > use_ping)