From c188dc8acb2a5518a9c206fb5dc94584dbc440d5 Mon Sep 17 00:00:00 2001
From: Zach Dykstra <dykstra.zachary@gmail.com>
Date: Sun, 17 Dec 2023 22:09:26 -0600
Subject: [PATCH] recovery shell: print zerrors since the last command was
 executed

---
 zfsbootmenu/bin/logs                       |  1 +
 zfsbootmenu/install-helpers.sh             |  2 +-
 zfsbootmenu/lib/kmsg-log-lib.sh            | 12 ++++++++----
 zfsbootmenu/libexec/recovery-error-printer | 18 ++++++++++++++++++
 4 files changed, 28 insertions(+), 5 deletions(-)
 create mode 120000 zfsbootmenu/bin/logs
 create mode 100755 zfsbootmenu/libexec/recovery-error-printer

diff --git a/zfsbootmenu/bin/logs b/zfsbootmenu/bin/logs
new file mode 120000
index 000000000..6a8efeda6
--- /dev/null
+++ b/zfsbootmenu/bin/logs
@@ -0,0 +1 @@
+zlogtail
\ No newline at end of file
diff --git a/zfsbootmenu/install-helpers.sh b/zfsbootmenu/install-helpers.sh
index 2178e3147..15d805b8b 100644
--- a/zfsbootmenu/install-helpers.sh
+++ b/zfsbootmenu/install-helpers.sh
@@ -151,7 +151,7 @@ create_zbm_profiles() {
 	[ -f /etc/profile ] && source /etc/profile
 	[ -f /lib/zfsbootmenu-completions.sh ] && source /lib/zfsbootmenu-completions.sh
 
-	export PS1="\[\033[0;33m\]zfsbootmenu\[\033[0m\] \w > "
+	export PS1='\$( /libexec/recovery-error-printer )\[\033[0;33m\]zfsbootmenu\[\033[0m\] \w > '
 
 	alias clear="tput clear"
 	alias reset="tput reset"
diff --git a/zfsbootmenu/lib/kmsg-log-lib.sh b/zfsbootmenu/lib/kmsg-log-lib.sh
index d953cf425..ba6dafe85 100755
--- a/zfsbootmenu/lib/kmsg-log-lib.sh
+++ b/zfsbootmenu/lib/kmsg-log-lib.sh
@@ -86,6 +86,7 @@ zerror() {
 }
 
 # arg1: comma-separated log levels to print
+# arg2: optional date that messages must be timestamped after
 # prints: all logs at that level
 # returns: nothing
 
@@ -98,14 +99,17 @@ print_kmsg_logs() {
     return
   fi
 
-  # Try to use feature flags found in dmesg from util-linux
-  if output="$( dmesg --notime -f user --color=always -l "${levels}" 2>/dev/null )" ; then
-    echo -e "${output}"
+  since="${2}"
+
+  # dmesg from dmesg-util can helpfully do --since, but only if it's also allowed to print the time out
+  # so always print the time, optionally set --since, and filter the timestamp after
+  if output="$( dmesg -f user -l "${levels}" ${since:+--since ${since}} 2>/dev/null )" ; then
+    echo -e "${output}" | sed 's/^\[.*\]\ //'
   else
     # Both util-linux and Busybox dmesg support the -r flag. However, the log level that is
     # reported by Busybox dmesg is larger than that reported by util-linux dmesg. Busybox dmesg
     # is too bare-bones to do much of anything, so we just need to grep for both integers at 
-    # a given log level, then refly on matching ZFSBootMenu for info and lower, and ZBM for debug.
+    # a given log level, then rely on matching ZFSBootMenu for info and lower, and ZBM for debug.
 
     IFS=',' read -r -a levels_array <<<"${levels}"
     for level in "${levels_array[@]}"; do
diff --git a/zfsbootmenu/libexec/recovery-error-printer b/zfsbootmenu/libexec/recovery-error-printer
new file mode 100755
index 000000000..f9301e486
--- /dev/null
+++ b/zfsbootmenu/libexec/recovery-error-printer
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+PROMPT_TS_FILE="${BASE}/errors_since"
+
+[ -f "${PROMPT_TS_FILE}" ] && read -r prompt_ts < "${PROMPT_TS_FILE}"
+
+# shellcheck disable=SC1091
+source /lib/kmsg-log-lib.sh || exit 0
+
+if [ -f "${BASE}/have_errors" ]; then 
+  echo -e -n "\n"
+  print_kmsg_logs "err" ${prompt_ts:+${prompt_ts}}
+  # trailing newlines are eaten by the prompt, so add a no-op carriage return
+  echo -n -e "\n\r"
+  rm "/zfsbootmenu/have_errors" 
+fi
+
+printf '%(%Y-%m-%dT%H:%M:%S)T' > "${PROMPT_TS_FILE}"