0001-notify-size-change-inband.patch

diff --git a/src/wslbridge2-backend.cpp b/src/wslbridge2-backend.cpp
index 8b86cc6..63a19e5 100644
--- a/src/wslbridge2-backend.cpp
+++ b/src/wslbridge2-backend.cpp
@@ -17,6 +17,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <wordexp.h>
+#include <limits.h> // PIPE_BUF
 
 #include <string>
 #include <vector>
@@ -196,6 +197,7 @@ int main(int argc, char *argv[])
 
         ssize_t readRet = 0, writeRet = 0;
         char data[1024]; /* Buffer to hold raw data from pty */
+        assert(sizeof data <= PIPE_BUF);
 
         do
         {
@@ -206,8 +208,85 @@ int main(int argc, char *argv[])
             if (fds[0].revents & POLLIN)
             {
                 readRet = recv(ioSockets.inputSock, data, sizeof data, 0);
-                if (readRet > 0)
-                    writeRet = write(mfd_dp, data, readRet);
+                char * s = data;
+                int len = readRet;
+                writeRet = 1;
+                while (writeRet > 0 && len > 0)
+                {
+                    if (!*s)
+                    {
+                        // dispatch NUL escaped inband information
+                        s++;
+                        len--;
+
+                        if (len < 9 && s + 9 >= data + sizeof data)
+                        {
+                            // make room for additional loading
+                            memcpy(data, s, len);
+                            s = data;
+                        }
+
+                        // ensure 1 more byte is loaded to dispatch on
+                        if (!len)
+                        {
+                            readRet = recv(ioSockets.inputSock, s, 1, 0);
+                            if (readRet > 0)
+                            {
+                                len += readRet;
+                            }
+                            else
+                            {
+                                writeRet = -1;
+                                break;
+                            }
+                        }
+                        if (*s == 2)
+                        {
+                            // STX: escaped NUL
+                            s++;
+                            len--;
+                            writeRet = write(mfd_dp, "", 1);
+                        }
+                        else if (*s == 16)
+                        {
+                            // DLE: terminal window size change
+                            s++;
+                            len--;
+                            // ensure 8 more bytes are loaded for winsize
+                            while (readRet > 0 && len < 8)
+                            {
+                                readRet = recv(ioSockets.inputSock, s + len, 8 - len, 0);
+                                if (readRet > 0)
+                                {
+                                    len += readRet;
+                                }
+                            }
+                            if (readRet <= 0)
+                            {
+                                writeRet = -1;
+                                break;
+                            }
+                            struct winsize * winsp = (struct winsize *)s;
+                            s += 8;
+                            len -= 8;
+                            winsp->ws_xpixel = 0;
+                            winsp->ws_ypixel = 0;
+                            ret = ioctl(mfd, TIOCSWINSZ, winsp);
+                            if (ret != 0)
+                                perror("ioctl(TIOCSWINSZ)");
+                        }
+                    }
+                    else
+                    {
+                        int n = strnlen(s, len);
+                        writeRet = write(mfd_dp, s, n);
+                        if (writeRet > 0)
+                        {
+                            s += writeRet;
+                            len -= writeRet;
+                        }
+                    }
+                }
             }
 
             /* Resize window when buffer received in control socket */
diff --git a/src/wslbridge2.cpp b/src/wslbridge2.cpp
index 300ad57..3ba9096 100644
--- a/src/wslbridge2.cpp
+++ b/src/wslbridge2.cpp
@@ -43,19 +43,41 @@ union IoSockets
 /* global variable */
 static volatile union IoSockets g_ioSockets = { 0 };
 
+#define dont_debug_inband
+#define dont_use_controlsocket
+
 static void resize_window(int signum)
 {
+#ifdef use_controlsocket
+#warning this may crash for unknown reason, maybe terminate the backend
     struct winsize winp;
+    ioctl(STDIN_FILENO, TIOCGWINSZ, &winp);
 
     /* Send terminal window size to control socket */
-    ioctl(STDIN_FILENO, TIOCGWINSZ, &winp);
     send(g_ioSockets.controlSock, (char *)&winp, sizeof winp, 0);
+#else
+    static char wins[2 + sizeof(struct winsize)] = {0, 16};
+    static struct winsize * winsp = (struct winsize *)&wins[2];
+    ioctl(STDIN_FILENO, TIOCGWINSZ, winsp);
+
+#ifdef debug_inband
+    /* Send terminal window size inband, visualized as ESC sequence */
+    char resizesc[55];
+    //sprintf(resizesc, "\e_8;%u;%u\a", winsp->ws_row, winsp->ws_col);
+    sprintf(resizesc, "^[_8;%u;%u^G", winsp->ws_row, winsp->ws_col);
+    send(g_ioSockets.inputSock, resizesc, strlen(resizesc), 0);
+#else
+    /* Send terminal window size inband, with NUL escape */
+    send(g_ioSockets.inputSock, wins, sizeof wins, 0);
+#endif
+#endif
 }
 
 static void* send_buffer(void *param)
 {
     int ret;
     char data[1024];
+    assert(sizeof data <= PIPE_BUF);
 
     while (1)
     {
@@ -65,8 +87,33 @@ static void* send_buffer(void *param)
             closesocket(g_ioSockets.inputSock);
             break;
         }
-        if (!send(g_ioSockets.inputSock, data, ret, 0))
-            break;
+            char * s = data;
+            int len = ret;
+            while (ret > 0 && len > 0)
+            {
+                if (!*s)
+                {
+                    // send NUL STX
+#ifdef debug_inband
+                    ret = send(g_ioSockets.inputSock, (void*)"nul", 3, 0);
+#else
+                    static char NUL_STX[] = {0, 2};
+                    ret = send(g_ioSockets.inputSock, NUL_STX, 2, 0);
+#endif
+                    s++;
+                    len--;
+                }
+                else
+                {
+                    int n = strnlen(s, len);
+                    ret = send(g_ioSockets.inputSock, s, n, 0);
+                    if (ret > 0)
+                    {
+                        s += ret;
+                        len -= ret;
+                    }
+                }
+            }
     }
 
     pthread_exit(&ret);
@@ -480,16 +527,6 @@ int main(int argc, char *argv[])
         g_ioSockets.controlSock = win_local_accept(controlSock);
     }
 
-    /* Capture window resize signal and send buffer to control socket */
-    {
-    struct sigaction act;
-    memset(&act, 0, sizeof act);
-    act.sa_handler = resize_window;
-    act.sa_flags = SA_RESTART;
-    ret = sigaction(SIGWINCH, &act, NULL);
-    assert(ret == 0);
-    }
-
     /* Create thread to send input buffer to input socket */
     pthread_t tidInput;
     ret = pthread_create(&tidInput, nullptr, send_buffer, nullptr);
@@ -502,6 +539,17 @@ int main(int argc, char *argv[])
 
     termState.enterRawMode();
 
+    /* Create thread to send window size through control socket */
+    struct sigaction act = {};
+    act.sa_handler = resize_window;
+    act.sa_flags = SA_RESTART;
+    ret = sigaction(SIGWINCH, &act, NULL);
+    assert(ret == 0);
+
+    /* Notify initial size in case it's changed since starting */
+    //resize_window(0);
+    kill(getpid(), SIGWINCH);
+
     /*
      * wsltty#254: WORKAROUND: Terminates input thread forcefully
      * when output thread exits. Need some inter-thread syncing.