The C Kconfig implementation (scripts/kconfig/confdata.c) stores string values from .config files verbatim -- no unescaping on read, no escaping on write. But kconfiglib's unescape() strips backslashes before ANY character (\n -> n, \x -> x), and escape() only re-adds them for \ and ". This means \n in a .config string silently becomes n after a round-trip.
Fix unescape() to only handle \" (the only escape that matters for .config parsing), and escape() to only handle " -> \". This makes string values pass through unchanged, matching the C behaviour. Also fix _expand_str() (the Kconfig file string parser) to only consume \\, \", \', and \$ (meaningful Kconfig escapes), leaving \n and similar sequences as-is. Signed-off-by: Simon Glass <[email protected]> --- tools/buildman/kconfiglib.py | 30 ++++++++++++++++++------------ 1 file changed, 18 insertions(+), 12 deletions(-) diff --git a/tools/buildman/kconfiglib.py b/tools/buildman/kconfiglib.py index 27abbf9a7a1..1bf96e35249 100644 --- a/tools/buildman/kconfiglib.py +++ b/tools/buildman/kconfiglib.py @@ -2727,10 +2727,14 @@ class Kconfig(object): return (s, match.end()) elif match.group() == "\\": - # Replace '\x' with 'x'. 'i' ends up pointing to the character - # after 'x', which allows macros to be canceled with '\$(foo)'. + # Replace '\x' with 'x' for characters that are meaningful + # escapes in Kconfig string literals: \\, \", \', and \$ + # (to cancel macro expansion). Other \<char> sequences + # like \n are left as-is, so that the stored value + # round-trips correctly through escape(). i = match.end() - s = s[:match.start()] + s[i:] + if i < len(s) and s[i] in "\\\"'$": + s = s[:match.start()] + s[i:] elif match.group() == "$(": # A macro call within the string @@ -6176,23 +6180,25 @@ def split_expr(expr, op): def escape(s): r""" - Escapes the string 's' in the same fashion as is done for display in - Kconfig format and when writing strings to a .config file. " and \ are - replaced by \" and \\, respectively. + Escapes the string 's' for writing to a .config file. Only " is escaped + (to \"), matching the symmetric unescape() behaviour. Backslash sequences + like \\ and \n are left as-is, since unescape() preserves them and the C + Kconfig implementation does not process them. """ - # \ must be escaped before " to avoid double escaping - return s.replace("\\", r"\\").replace('"', r'\"') + return s.replace('"', r'\"') def unescape(s): r""" - Unescapes the string 's'. \ followed by any character is replaced with just - that character. Used internally when reading .config files. + Unescapes the string 's'. \" is replaced with ". Other \<char> sequences, + including \\, are left as-is so that escape() can round-trip them + correctly. This matches the C Kconfig implementation which does not + unescape string values read from .config files. """ return _unescape_sub(r"\1", s) -# unescape() helper -_unescape_sub = re.compile(r"\\(.)").sub +# unescape() helper - only unescape \" +_unescape_sub = re.compile(r'\\(")').sub def standard_kconfig(description=None): -- 2.43.0
