Stop reporting a closed console as a user abort, and shield the host's own work

core/core.func

@@ -958,7 +958,11 @@ _cs_reattach_output() {
   exec </dev/null >>"$log" 2>&1
 }
 
-_silent_exec() {
+# A closed console sends SIGHUP to every process in the foreground group, and a
+# program that does not handle it dies. Run the long ones through here: the
+# subshell sets the signal to ignore, which exec carries into the program, so
+# it finishes even though the terminal is gone.
+_cs_shield_hangup() {
   (
     trap '' HUP
     exec "$@"
@@ -999,7 +1003,7 @@ silent() {
   local rc run=("$@")
   case "$(type -t "$1" 2>/dev/null)" in
   function | builtin | "") ;;
-  *) run=(_silent_exec "$@") ;;
+  *) run=(_cs_shield_hangup "$@") ;;
   esac
   if [[ "${VERBOSE:-no}" == "yes" ]]; then
     # Not a pipe: the command must stay in this shell so functions keep their side effects.

core/error_handler.func

@@ -889,7 +889,7 @@ on_hangup() {
   [[ -n "$log" ]] || log="${INSTALL_LOG:-${BUILD_LOG:-/dev/null}}"
   exec </dev/null >>"$log" 2>&1
   export _CS_HANGUP=1 CS_ANIMATION_OK=0 _CS_HANGUP_LOG="$log"
-  echo "[WARN] $(date '+%Y-%m-%d %H:%M:%S') The terminal hung up (SIGHUP); continuing, output follows here. (pid $$, subshell ${BASH_SUBSHELL}, during: ${BASH_COMMAND:-?})"
+  echo "[WARN] $(date '+%Y-%m-%d %H:%M:%S') The terminal closed; continuing, output follows here. (pid $$, subshell ${BASH_SUBSHELL}, during: ${BASH_COMMAND:-?})"
 }
 
 # ==============================================================================

docs/backends.md

@@ -16,9 +16,10 @@ wizard calls.
 | [`vm-core.func`](../pve/vm-core.func) | VM creation via `qm`, including disk import and template handling |
 | [`vm-app.func`](../pve/vm-app.func) | Deploys an application that normally goes into an LXC container into a full VM instead |
 
-A closed console is not an abort. SIGHUP reaches the host script and the
+A closed console is not an abort. The hangup reaches the host script and the
 install inside the container; both carry on with their output in their logs
-(`on_hangup`), external commands under `$STD` ignore the signal, and when
+(`on_hangup`), the long-running commands on either side run through
+`_cs_shield_hangup` so the signal cannot reach them, and when
 lxc-attach dies with the terminal the host waits for the container's
 `.done`/`.failed` markers (`_pve_wait_for_detached_install`) before it
 reports. Ctrl-C still aborts.

incus/build.func

@@ -642,7 +642,7 @@ _incus_on_hangup() {
   [[ -n "$log" ]] || log="/tmp/incus-hangup-${SESSION_ID:-$$}.log"
   exec </dev/null >>"$log" 2>&1
   export _CS_HANGUP=1 _CS_HANGUP_LOG="$log" CS_STDIN_OK=0
-  echo "[WARN] $(date '+%Y-%m-%d %H:%M:%S') The terminal hung up (SIGHUP); continuing, output follows here."
+  echo "[WARN] $(date '+%Y-%m-%d %H:%M:%S') The terminal closed; continuing, output follows here."
 }
 
 trap 'api_exit_script' EXIT

pve/backend.func

@@ -138,7 +138,7 @@ _pct_create() {
   local prev rc
   prev="$(umask)"
   umask 022
-  pct create "$@"
+  _cs_shield_hangup pct create "$@"
   rc=$?
   umask "$prev"
   return $rc
@@ -2726,7 +2726,7 @@ create_lxc_container() {
 
     if [[ ! -f "$fallback_path" ]]; then
       msg_info "Downloading $os_type $fallback_ver template"
-      if ! pveam download "$TEMPLATE_STORAGE" "$fallback_template" >>"${BUILD_LOG:-/dev/null}" 2>&1; then
+      if ! _cs_shield_hangup pveam download "$TEMPLATE_STORAGE" "$fallback_template" >>"${BUILD_LOG:-/dev/null}" 2>&1; then
         msg_error "Failed to download $os_type $fallback_ver template."
         return 1
       fi
@@ -3024,7 +3024,7 @@ create_lxc_container() {
     if [[ -n "$CUSTOM_TEMPLATE_PATH" ]]; then
       download_catalog_template "$dest"
     else
-      pveam download "$TEMPLATE_STORAGE" "$TEMPLATE" >>"${BUILD_LOG:-/dev/null}" 2>&1 || {
+      _cs_shield_hangup pveam download "$TEMPLATE_STORAGE" "$TEMPLATE" >>"${BUILD_LOG:-/dev/null}" 2>&1 || {
         msg_error "Failed to download template '$TEMPLATE' to storage '$TEMPLATE_STORAGE'"
         exit 222
       }
@@ -3446,7 +3446,7 @@ create_lxc_container() {
       local _dl_out="" _fresh=""
       for attempt in {1..3}; do
         msg_info "Attempt $attempt: Downloading template $TEMPLATE to $TEMPLATE_STORAGE"
-        _dl_out="$(pveam download "$TEMPLATE_STORAGE" "$TEMPLATE" 2>&1)" || true
+        _dl_out="$(_cs_shield_hangup pveam download "$TEMPLATE_STORAGE" "$TEMPLATE" 2>&1)" || true
         printf '%s\n' "$_dl_out" >>"${BUILD_LOG:-/dev/null}"
         # pveam can report a failed download and still exit 0, so only the
         # template in storage counts as success.
@@ -3655,7 +3655,7 @@ create_lxc_container() {
             if [[ -n "$CUSTOM_TEMPLATE_PATH" ]]; then
               download_catalog_template "$LOCAL_TEMPLATE_PATH"
             else
-              pveam download local "$TEMPLATE" >>"${BUILD_LOG:-/dev/null}" 2>&1
+              _cs_shield_hangup pveam download local "$TEMPLATE" >>"${BUILD_LOG:-/dev/null}" 2>&1
             fi
             msg_ok "Template downloaded to local"
           else

tests/console-hangup.sh

@@ -6,7 +6,7 @@
 set -uo pipefail
 
 CORE_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)"
-eval "$(awk '/^(silent|_silent_exec|_cs_reattach_output)[(][)] [{]/,/^}/' "$CORE_DIR/core/core.func")"
+eval "$(awk '/^(silent|_cs_shield_hangup|_cs_reattach_output)[(][)] [{]/,/^}/' "$CORE_DIR/core/core.func")"
 eval "$(awk '/^(on_hangup|on_exit|_eh_quiet_spinner)[(][)] [{]/,/^}/' "$CORE_DIR/core/error_handler.func")"
 eval "$(awk '/^_pve_wait_for_detached_install[(][)] [{]/,/^}/' "$CORE_DIR/pve/backend.func")"
 
@@ -53,7 +53,7 @@ rc=$?
 expect "the shell survives the hangup" 0 "$rc"
 expect "nothing more reaches the terminal" "" "$out"
 expect "later output lands in the log" 1 "$(grep -c 'after hangup' "$LOG")"
-expect "the hangup is noted in the log" 1 "$(grep -c SIGHUP "$LOG")"
+expect "the hangup is noted in the log" 1 "$(grep -c 'The terminal closed' "$LOG")"
 expect "the run knows it is detached" 1 "$(grep -c 'flag=1' "$LOG")"
 
 # on_exit(): a clean install leaves .done for the host; a failed one does not.
@@ -137,5 +137,33 @@ expect "and not back to the original target" 0 "$(grep -c 'after the redirected
 expect "without a hangup nothing is redirected" 0 "$(grep -c 'no hangup' "$AFTER" 2>/dev/null)"
 expect "it stays where it was" 1 "$(grep -c 'no hangup' "$TEST_DIR/orig2.log" 2>/dev/null)"
 
+# The telemetry service decides what counts as a user abort by searching the
+# log text, so a word in one of our own messages is enough to file a failure
+# as "the operator pressed Ctrl-C". A closed console is not that, and 81 of
+# 300 aborted records were this message rather than a person.
+CLASSIFIER_TOKENS="sigint ctrl+c ctrl-c sighup aborted by user user abort cancelled by user no changes have been made"
+hangup_text="$(awk '/^on_hangup[(][)] [{]/,/^}/' "$CORE_DIR/core/error_handler.func")
+$(awk '/^_incus_on_hangup[(][)] [{]/,/^}/' "$CORE_DIR/incus/build.func")"
+hits=0
+while IFS= read -r token; do
+  [[ -n "$token" ]] || continue
+  if printf '%s' "${hangup_text,,}" | grep -qF "$token"; then
+    echo "  token in a hangup message: $token" >&2
+    hits=$((hits + 1))
+  fi
+done <<<"$(printf '%s
+' $CLASSIFIER_TOKENS | sed 's/^ *//')"
+expect "no hangup message reads as a user abort" 0 "$hits"
+expect "both hangup handlers were found" 2 "$(grep -c 'continuing, output follows here' <<<"$hangup_text")"
+
+# The helper the long host commands go through has to survive the signal.
+: >"$LOG"
+_cs_shield_hangup sh -c 'kill -HUP $$; echo shielded >>"'"$LOG"'"'
+expect "a shielded command survives SIGHUP" 0 "$?"
+expect "and ran to the end" 1 "$(grep -c shielded "$LOG")"
+unshielded_rc=0
+{ sh -c 'kill -HUP $$; echo unshielded' >/dev/null 2>&1 || unshielded_rc=$?; } 2>/dev/null
+expect "without the shield the same command dies" 129 "$unshielded_rc"
+
 echo "$passed passed, $failed failed"
 ((failed == 0))

tests/failed-command-output.sh

@@ -2,7 +2,7 @@
 set -uo pipefail
 
 CORE_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/.." && pwd)"
-eval "$(awk '/^(silent|set_std_mode|_silent_exec|_cs_reattach_output)[(][)] [{]/,/^}/' "$CORE_DIR/core/core.func")"
+eval "$(awk '/^(silent|set_std_mode|_cs_shield_hangup|_cs_reattach_output)[(][)] [{]/,/^}/' "$CORE_DIR/core/core.func")"
 eval "$(awk '/^_eh_print_failed_output[(][)] [{]/,/^}/' "$CORE_DIR/core/error_handler.func")"
 
 TEST_DIR="$(mktemp -d)"

ui/API.txt

@@ -15,6 +15,7 @@ _cs_run_os_section
 _cs_run_update
 _cs_runtime_cache_dir
 _cs_scripts_ref_line
+_cs_shield_hangup
 _cs_stdin_source
 _dev_step_end
 _dev_step_key
@@ -51,7 +52,6 @@ _pve_version
 _pveam_available
 _pveam_update
 _sanitize_value
-_silent_exec
 _stop_container_if_installing
 _telemetry_report_exit
 _tm_clean_log