[U-Boot] [PATCH v2 1/9] moveconfig: expand simple expressions

[Heinrich Schuchardt]

On 5/15/19 3:15 PM, Markus Klotzbuecher wrote:
> From: Markus Klotzbuecher <markus.klotzbuecher at kistler.com>
>
> Add support for expanding simple expressions and sizes such as
> "(4 * 1024)", "(512 << 10)" or "(SZ_256K)".
>
> This can help to significantly reduce the number of "suspicious"
> moves, such as
>
>   'CONFIG_ENV_SIZE="(64 << 10)"' was removed by savedefconfig.
>
> If the expansion fails, it falls back to the original string.
>
> Signed-off-by: Markus Klotzbuecher <markus.klotzbuecher at kistler.com>
> Cc: Masahiro Yamada <yamada.masahiro at socionext.com>
> Cc: Heiko Schocher <hs at denx.de>
> ---
> Changes for v2: new patch
>
>   tools/moveconfig.py | 41 +++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 41 insertions(+)
>
> diff --git a/tools/moveconfig.py b/tools/moveconfig.py
> index 1a214c5605..0bbc7c1991 100755
> --- a/tools/moveconfig.py
> +++ b/tools/moveconfig.py
> @@ -354,6 +354,26 @@ CONFIG_DATABASE = 'moveconfig.db'
>
>   CONFIG_LEN = len('CONFIG_')
>
> +SIZES = {
> +    "SZ_1":    0x00000001, "SZ_2":    0x00000002,
> +    "SZ_4":    0x00000004, "SZ_8":    0x00000008,
> +    "SZ_16":   0x00000010, "SZ_32":   0x00000020,
> +    "SZ_64":   0x00000040, "SZ_128":  0x00000080,
> +    "SZ_256":  0x00000100, "SZ_512":  0x00000200,
> +    "SZ_1K":   0x00000400, "SZ_2K":   0x00000800,
> +    "SZ_4K":   0x00001000, "SZ_8K":   0x00002000,
> +    "SZ_16K":  0x00004000, "SZ_32K":  0x00008000,
> +    "SZ_64K":  0x00010000, "SZ_128K": 0x00020000,
> +    "SZ_256K": 0x00040000, "SZ_512K": 0x00080000,
> +    "SZ_1M":   0x00100000, "SZ_2M":   0x00200000,
> +    "SZ_4M":   0x00400000, "SZ_8M":   0x00800000,
> +    "SZ_16M":  0x01000000, "SZ_32M":  0x02000000,
> +    "SZ_64M":  0x04000000, "SZ_128M": 0x08000000,
> +    "SZ_256M": 0x10000000, "SZ_512M": 0x20000000,
> +    "SZ_1G":   0x40000000, "SZ_2G":   0x80000000,
> +    "SZ_4G":  0x100000000
> +}
> +
>   ### helper functions ###
>   def get_devnull():
>       """Get the file object of '/dev/null' device."""
> @@ -777,6 +797,25 @@ def cleanup_readme(configs, options):
>       with open('README', 'w') as f:
>           f.write(''.join(newlines))
>
> +def try_expand(line):
> +    """If value looks like an expression, try expanding it
> +    Otherwise just return the existing value
> +    """
> +    if line.find('=') == -1:
> +        return line
> +
> +    try:
> +        cfg, val = re.split("=", line)
> +        val= val.strip('\"')
> +        if re.search("[*+-/]|<<|SZ_+|\(([^\)]+)\)", val):
> +            newval = hex(eval(val, SIZES))

The if clause evaluates to true for values like:

     val = "os.execl('/sbin/fdisk')"

As eval() can be used to execute arbitrary commands this patch should be
corrected.

Best regards

Heinrich

> +            print "\tExpanded expression %s to %s" % (val, newval)
> +            return cfg+'='+newval
> +    except:
> +        print "\tFailed to expand expression in %s" % line
> +
> +    return line
> +
>
>   ### classes ###
>   class Progress:
> @@ -891,6 +930,8 @@ class KconfigParser:
>           else:
>               new_val = not_set
>
> +        new_val = try_expand(new_val)
> +
>           for line in dotconfig_lines:
>               line = line.rstrip()
>               if line.startswith(config + '=') or line == not_set:
>