fix(cron): 防止权限或读取失败清空定时任务

2026-10-24 11:49:20 +00:00 · 2026-10-03 04:27:42 +08:00
parent de1d9e20f7
commit 88eb7efd8a
4 changed files with 116 additions and 48 deletions
@@ -1,41 +1,95 @@
-
 crondir="$(crond -h 2>&1 | grep -oE 'Default:.*' | awk -F ":" '{print $2}'| tr -d ' ')"
 [ ! -w "$crondir" ] && crondir="/etc/storage/cron/crontabs"
 [ ! -w "$crondir" ] && crondir="/var/spool/cron/crontabs"
 [ ! -w "$crondir" ] && crondir="/var/spool/cron"
-[ -z "$USER" ] && USER=$(whoami 2>/dev/null)
+[ -z "$USER" ] && USER=$(id -un)
 [ -z "$TASKCFGDIR" ] && TASKCFGDIR="$CRASHDIR"/configs/task
-tmpcron=/tmp/cron_tmp
-touch "$tmpcron"

-cronadd() { #定时任务工具
-    if crontab -h 2>&1 | grep -q '\-l'; then
-        crontab "$1"
-    elif [ -w "$crondir" ];then
-        cat "$1" >"$crondir"/"$USER" && cru a REFRESH "0 0 1 1 * /bin/true" 2>/dev/null
-    else
-        echo "找不到可用的crond或者crontab应用！No available crond or crontab application can be found!"
-    fi
-}
-cronload() { #定时任务工具
-    if crontab -h 2>&1 | grep -q '\-l'; then
-        crontab -l
-    elif [ -f "$crondir/$USER" ];then
-        cat "$crondir"/"$USER" 2>/dev/null
-    else
+# ShellCrash 使用的 ash/bash（以及 dash）均支持 test -O。
+# shellcheck disable=SC3067
+croncheck() { #在任何写操作前检查实例管理权限，保留普通用户自己的安装
+    cron_uid=$(id -u) || return 1
+    [ "$cron_uid" = 0 ] && return 0
+    if [ ! -O "$CRASHDIR/configs/ShellCrash.cfg" ] || [ ! -w "$CRASHDIR/configs/ShellCrash.cfg" ]; then
+        echo '无权管理此 ShellCrash 实例，请使用安装用户或 root。' >&2
        return 1
    fi
+    for cron_pid in $(pidof CrashCore 2>/dev/null); do
+        if [ ! -O "/proc/$cron_pid" ]; then
+            echo '无权管理其他用户启动的 CrashCore。' >&2
+            return 1
+        fi
+    done
 }
-cronset() { #定时任务设置
-    # 参数1代表要移除的关键字,参数2代表要添加的任务语句
-    cronload | grep -v '^$' | grep -vF "$1" >"$tmpcron"
-    [ -n "$2" ] && echo "$2" >>"$tmpcron"
-    cronadd "$tmpcron"
-    #华硕/Padavan固件存档在本地,其他则删除
-    if [ -d /jffs ] || [ -d /etc/storage/ShellCrash ];then
-        mkdir -p "$TASKCFGDIR"
-        mv -f "$tmpcron" "$TASKCFGDIR"/cron
+
+cronadd() ( #定时任务工具；子 shell 隔离临时变量和清理 trap
+    croncheck || exit 1
+    [ -f "$1" ] && [ -r "$1" ] || exit 1
+    if crontab -h 2>&1 | grep -q '\-l'; then
+        crontab "$1"
+    elif [ -w "$crondir" ]; then
+        cron_user=$(id -un) || exit 1
+        cron_stage=$(mktemp "$crondir/.shellcrash.XXXXXX") || exit 1
+        trap 'rm -f "$cron_stage"' 0
+        trap 'exit 1' 1 2 3 15
+        [ ! -e "$crondir/$cron_user" ] || cp -p "$crondir/$cron_user" "$cron_stage" || exit 1
+        cat "$1" >"$cron_stage" && mv -f "$cron_stage" "$crondir/$cron_user" || exit 1
+        if command -v cru >/dev/null 2>&1; then
+            cru a REFRESH "0 0 1 1 * /bin/true"
+        fi
    else
-        rm -f "$tmpcron"
+        echo '找不到可用的 crond 或 crontab！No available crond or crontab!' >&2
+        exit 1
    fi
-}
+)
+
+cronload() (
+    cron_user=$(id -un) || exit 1
+    if crontab -h 2>&1 | grep -q '\-l'; then
+        cron_text=$(LC_ALL=C crontab -l 2>&1)
+        cron_status=$?
+        if [ "$cron_status" = 0 ]; then
+            [ -z "$cron_text" ] || printf '%s\n' "$cron_text"
+            exit 0
+        fi
+        #首次使用没有 crontab 是合法空表，其他错误必须传回调用者。
+        case "$cron_text" in
+            "no crontab for $cron_user" | "crontab: can't open '$cron_user': No such file or directory") exit 0 ;;
+        esac
+        printf '%s\n' "$cron_text" >&2
+        exit "$cron_status"
+    elif [ -d "$crondir" ] && [ -r "$crondir" ] && [ -x "$crondir" ]; then
+        [ -e "$crondir/$cron_user" ] || [ -L "$crondir/$cron_user" ] || exit 0
+        cat "$crondir/$cron_user"
+    else
+        echo '无法读取原有 crontab，已取消修改。' >&2
+        exit 1
+    fi
+)
+
+cronupdate() ( #成功读取、生成后才提交；参数是读取 stdin 的过滤命令
+    croncheck || exit 1
+    cron_tmp=$(mktemp -d /tmp/ShellCrash-cron.XXXXXX) || exit 1
+    cron_saved=
+    trap 'rm -rf "$cron_tmp"; [ -z "$cron_saved" ] || rm -f "$cron_saved"' 0
+    trap 'exit 1' 1 2 3 15
+    cronload >"$cron_tmp/old" || exit 1
+    "$@" <"$cron_tmp/old" >"$cron_tmp/new" || exit 1
+    #先准备华硕/Padavan 的持久化副本；任何提交前的写入失败都保留原表。
+    if [ "$cron_persist" = true ] && { [ -d /jffs ] || [ -d /etc/storage/ShellCrash ]; }; then
+        mkdir -p "$TASKCFGDIR" || exit 1
+        cron_saved=$(mktemp "$TASKCFGDIR/.cron.XXXXXX") || exit 1
+        cat "$cron_tmp/new" >"$cron_saved" || exit 1
+    fi
+    cronadd "$cron_tmp/new" || exit 1
+    [ -z "$cron_saved" ] || mv -f "$cron_saved" "$TASKCFGDIR/cron"
+)
+
+cronset() ( #参数1：移除的文字；参数2：新增任务。空结果也是合法 crontab。
+    cron_persist=true
+    # shellcheck disable=SC2016
+    CRON_KEY="$1" CRON_TASK="$2" cronupdate awk '
+        NF && !index($0, ENVIRON["CRON_KEY"]) { print }
+        END { if (ENVIRON["CRON_TASK"] != "") print ENVIRON["CRON_TASK"] }
+    '
+)