core: prefer raw binary on compressed rom, avoid upx on tmpfs devices

Adds store_on_rom() helper (tmpfs $TMPDIR + squashfs/ubifs/overlay
$BINDIR). On such devices core_webget no longer downloads the upx core
(its stub decompresses into a memfd = RAM at runtime); it fetches the
tar.gz instead and core_check stores the naked binary as
$BINDIR/CrashCore.raw, symlinked from $TMPDIR. The binary is
transparently compressed on rom and file-backed/reclaimable at runtime
(RssShmem 0). Other filesystems and explicit upx keep prior behavior.

Also corrects the upx branch symlink target $TMPDIR -> $BINDIR (same
dangling-symlink issue as #1295).

For #1304

scripts/libs/core_tools.sh

@@ -2,6 +2,14 @@
 
 [ -n "$(find --help 2>&1 | grep -o size)" ] && find_para=' -size +2000'             #find命令兼容
 
+#$TMPDIR为内存(tmpfs)且$BINDIR在透明压缩文件系统(squashfs/ubifs/overlay)上时返回0
+#此类设备应把裸二进制存于$BINDIR(rom透明压缩)并软链，而非解压/memfd占用内存
+store_on_rom(){
+    case "$(df -T "$TMPDIR" 2>/dev/null | awk 'END{print $2}')" in tmpfs|ramfs) ;; *) return 1 ;; esac
+    case "$(df -T "$BINDIR" 2>/dev/null | awk 'END{print $2}')" in squashfs|ubifs|overlay|overlayfs) return 0 ;; esac
+    return 1
+}
+
 core_unzip() { #$1:需要解压的文件 $2:目标文件名
     if echo "$1" |grep -q 'tar.gz$' ;then
         [ "$BINDIR" = "$TMPDIR" ] && rm -rf "$TMPDIR"/CrashCore #小闪存模式防止空间不足
@@ -48,18 +56,11 @@ core_check(){
         return 2
     else
         rm -f "$BINDIR"/CrashCore.tar.gz "$BINDIR"/CrashCore.gz "$BINDIR"/CrashCore.upx "$BINDIR"/CrashCore.raw
-        #$TMPDIR为内存(tmpfs)且$BINDIR为透明压缩文件系统(squashfs/ubifs)时，直接以裸二进制存于$BINDIR并软链，省内存
-        store_raw=0
-        tmp_fs=$(df -T "$TMPDIR" 2>/dev/null | awk 'END{print $2}')
-        rom_fs=$(df -T "$BINDIR" 2>/dev/null | awk 'END{print $2}')
-        case "$tmp_fs" in tmpfs|ramfs)
-            case "$rom_fs" in squashfs|ubifs|overlay|overlayfs) store_raw=1 ;; esac ;;
-        esac
         if [ "$zip_type" = 'upx' ];then
             mv -f "$1" "$BINDIR/CrashCore.upx"
             rm -f "$TMPDIR"/core_new
             ln -sf "$BINDIR/CrashCore.upx" "$TMPDIR/CrashCore"
-        elif [ "$store_raw" = 1 ];then
+        elif store_on_rom ;then
             rm -f "$1"
             mv -f "$TMPDIR/core_new" "$BINDIR/CrashCore.raw"
             ln -sf "$BINDIR/CrashCore.raw" "$TMPDIR/CrashCore"
@@ -83,6 +84,8 @@ core_webget(){
     . "$CRASHDIR"/libs/check_target.sh
     if [ -z "$custcorelink" ];then
         [ -z "$zip_type" ] && zip_type='tar.gz'
+        #压缩rom+内存tmp设备避免下载upx(运行时memfd占RAM)，改取tar.gz的裸二进制存于rom
+        [ "$zip_type" = 'upx' ] && store_on_rom && zip_type='tar.gz'
         get_bin "$TMPDIR/Coretmp.$zip_type" "bin/$crashcore/${target}-linux-${cpucore}.$zip_type"
     else
         case "$custcorelink" in