From fda9415873eccf15f677a98ae96a7681e3fa1482 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Thu, 24 Feb 2022 19:41:21 +0530
Subject: [PATCH] Use a record separator to delimit the start of data

Needed because the user could press keys and send data to the tty
before kitty can send the ssh data
---
 kittens/ssh/main.py                |  2 +-
 shell-integration/ssh/bootstrap.sh | 16 ++++++++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/kittens/ssh/main.py b/kittens/ssh/main.py
index a8c38e452..e152feda6 100644
--- a/kittens/ssh/main.py
+++ b/kittens/ssh/main.py
@@ -58,7 +58,7 @@ def get_ssh_data(msg: str, shell_integration_dest: str = DEFAULT_SHELL_INTEGRATI
         else:
             from base64 import standard_b64encode
             encoded_data = standard_b64encode(data)
-            yield f"{len(encoded_data)}:".encode('ascii')
+            yield f"\036{len(encoded_data)}:".encode('ascii')
             yield encoded_data
 
 
diff --git a/shell-integration/ssh/bootstrap.sh b/shell-integration/ssh/bootstrap.sh
index 51209c293..64bfc5f40 100644
--- a/shell-integration/ssh/bootstrap.sh
+++ b/shell-integration/ssh/bootstrap.sh
@@ -7,7 +7,7 @@ cleanup_on_bootstrap_exit() {
     [ ! -z "$saved_tty_settings" ] && command stty "$saved_tty_settings"
 }
 
-die() { echo "$*" >/dev/stderr; cleanup_on_bootstrap_exit; exit 1; }
+die() { echo "$*" > /dev/stderr; cleanup_on_bootstrap_exit; exit 1; }
 dsc_to_kitty() { printf "\033P@kitty-$1|%s\033\\" "$(printf "%s" "$2" | base64)"; }
 debug() { dsc_to_kitty "print" "debug $1"; }
 echo_via_kitty() { dsc_to_kitty "echo" "$1"; }
@@ -50,11 +50,19 @@ get_data() {
     # head -c reads beyond the specified number of bytes into an internal buffer on macOS
     #
     # POSIX dd works for one byte at a time but for reading X bytes it needs the GNU iflag=count_bytes
-    # extension. 
+    # extension, and is anyway unsafe as it can lead to corrupt output when the read syscall is interrupted.
+    record_started=0
+    record_separator=$(printf "\036")
     while :; do
         n=$(command dd bs=1 count=1 2> /dev/null) 
-        if [ "$n" = ":" ]; then break; fi
-        size="$size$n"
+        if [ $record_started = 1 ]; then
+            if [ "$n" = ":" ]; then break; fi
+            size="$size$n"
+        else
+            if [ "$n" = "$record_separator" ]; then 
+                record_started=1; 
+            fi
+        fi
     done
     # using dd with bs=1 is very slow on Linux, so use head 
     command head -c "$size" | untar