From 591586619cf78f8a0e00cd5d2f8166831799c8b8 Mon Sep 17 00:00:00 2001
From: Tom Hale <HaleTom@users.noreply.github.com>
Date: Tue, 22 Apr 2025 01:11:13 +0200
Subject: [PATCH 1/3] ssh_filter_btrbk.sh: support zstd `--long[=#] --adapt`

Allow for `zstd`-specific options to be set:
- `stream_compress_long`
- `stream_compress_adapt`
---
 ssh_filter_btrbk.sh | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/ssh_filter_btrbk.sh b/ssh_filter_btrbk.sh
index 0817563..7234311 100755
--- a/ssh_filter_btrbk.sh
+++ b/ssh_filter_btrbk.sh
@@ -78,8 +78,8 @@ reject_filtered_cmd()
     path_match="(${path_match}|${path_match_legacy})"
 
     if [ -n "${allow_compress}" ]; then
-        decompress_match="(${compress_list}) -d -c( -[pT][0-9]+)?"
-        compress_match="(${compress_list}) -c( -[0-9])?( -[pT][0-9]+)?"
+	decompress_match="(${compress_list}) -d -c( -[pT][0-9]+)?( --long(=[0-9]+)?)?( --adapt)?"
+        compress_match="(${compress_list}) -c( -[0-9])?( -[pT][0-9]+)?( --long(=[0-9]+)?)?( --adapt)?"
     else
         decompress_match=
         compress_match=
@@ -102,12 +102,12 @@ reject_filtered_cmd()
     # when an error occurred.
 
     allow_stream_match="^${stream_in_match}${allow_cmd_match}${stream_out_match}"
-    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -E "${allow_stream_match}" >/dev/null 2>/dev/null; then
+    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -E -- "${allow_stream_match}" >/dev/null 2>/dev/null; then
         return 0
     fi
 
     exact_cmd_match="^(${allow_exact_list})$";
-    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -E "${exact_cmd_match}" >/dev/null 2>/dev/null; then
+    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -E -- "${exact_cmd_match}" >/dev/null 2>/dev/null; then
         return 0
     fi
 

From e68430cbe8083478d1781df99f9445beb2038bc9 Mon Sep 17 00:00:00 2001
From: Tom Hale <HaleTom@users.noreply.github.com>
Date: Tue, 22 Apr 2025 03:21:02 +0200
Subject: [PATCH 2/3] Use grep -q rather than producing output to /dev/null

---
 ssh_filter_btrbk.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ssh_filter_btrbk.sh b/ssh_filter_btrbk.sh
index 7234311..be9eb96 100755
--- a/ssh_filter_btrbk.sh
+++ b/ssh_filter_btrbk.sh
@@ -102,12 +102,12 @@ reject_filtered_cmd()
     # when an error occurred.
 
     allow_stream_match="^${stream_in_match}${allow_cmd_match}${stream_out_match}"
-    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -E -- "${allow_stream_match}" >/dev/null 2>/dev/null; then
+    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -Eq -- "${allow_stream_match}"; then
         return 0
     fi
 
     exact_cmd_match="^(${allow_exact_list})$";
-    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -E -- "${exact_cmd_match}" >/dev/null 2>/dev/null; then
+    if printf '%s' "${SSH_ORIGINAL_COMMAND}" | grep -Eq -- "${exact_cmd_match}"; then
         return 0
     fi
 

From 03c1d7fb1ae6e483b5472cdb384b48cd6c315e88 Mon Sep 17 00:00:00 2001
From: Tom Hale <HaleTom@users.noreply.github.com>
Date: Fri, 25 Apr 2025 09:59:17 +0200
Subject: [PATCH 3/3] Allow 2 digits as argument to compressor's `-c`

Support compression `-c` argument with more than one digit (eg zstd compression levels 10 to 22)
---
 ssh_filter_btrbk.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ssh_filter_btrbk.sh b/ssh_filter_btrbk.sh
index be9eb96..b9b4a36 100755
--- a/ssh_filter_btrbk.sh
+++ b/ssh_filter_btrbk.sh
@@ -79,7 +79,7 @@ reject_filtered_cmd()
 
     if [ -n "${allow_compress}" ]; then
 	decompress_match="(${compress_list}) -d -c( -[pT][0-9]+)?( --long(=[0-9]+)?)?( --adapt)?"
-        compress_match="(${compress_list}) -c( -[0-9])?( -[pT][0-9]+)?( --long(=[0-9]+)?)?( --adapt)?"
+        compress_match="(${compress_list}) -c( -[0-9]{1,2})?( -[pT][0-9]+)?( --long(=[0-9]+)?)?( --adapt)?"
     else
         decompress_match=
         compress_match=