2018-06-23 4:27 GMT+09:00 Dirk Gouders <dirk@xxxxxxxxxxx>:
> xfwrite uses assert() to ensure it does not operate on empty strings.
> Two users respect this, expr_print_file_helper() doesn't and causes
> segfaults e.g. when the dependency for an empty default string is printed.
>
> Fix this by calling xfwrite with an empty string pattern ("") for
> empty strings.
>
> INITRAMFS_SOURCE was one symbol that caused this problem, with this
> fix applied the zconfdump() output for this symbol looks as follows:
>
> ------------------------------------------------------------------------
> config INITRAMFS_SOURCE
> string
> symbol INITRAMFS_SOURCE
> prompt "Initramfs source file(s)" if BLK_DEV_INITRD
> default "" if BLK_DEV_INITRD
> help
> This can be either a single cpio archive with a .cpio suffix or a
> space-separated list of directories and files for building the
> initramfs image. A cpio archive should contain a filesystem archive
> to be used as an initramfs image. Directories should contain a
> filesystem layout to be included in the initramfs image. Files
> should contain entries according to the format described by the
> "usr/gen_init_cpio" program in the kernel tree.
>
> When multiple directories and files are specified then the
> initramfs image will be the aggregate of all of them.
>
> See <file:Documentation/early-userspace/README> for more details.
>
> If you are not sure, leave it blank.
> ------------------------------------------------------------------------
>
> Signed-off-by: Dirk Gouders <dirk@xxxxxxxxxxx>
> ---
Hmm, please let me think about this.
I know this is an easy way to fix the seg-fault,
but I think it is not a correct way.
If the config entry were like this:
config INITRAMFS_SOURCE
string "Initramfs source file(s)"
default "foo"
It would be dumped like this:
config INITRAMFS_SOURCE
string
symbol INITRAMFS_SOURCE
prompt "Initramfs source file(s)"
default foo
I want it to be displayed like this:
default "foo"
If we can quote the string values,
the problem will be eventually fixed.
It may not be easy to fix it...
> scripts/kconfig/expr.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
> index e1a39e90841d..e064bf4c2881 100644
> --- a/scripts/kconfig/expr.c
> +++ b/scripts/kconfig/expr.c
> @@ -1231,7 +1231,10 @@ void expr_print(struct expr *e,
>
> static void expr_print_file_helper(void *data, struct symbol *sym, const char *str)
> {
> - xfwrite(str, strlen(str), 1, data);
> + if (*str != '\0')
> + xfwrite(str, strlen(str), 1, data);
> + else
> + xfwrite("\"\"", 2, 1, data);
> }
>
> void expr_fprint(struct expr *e, FILE *out)
> --
> 2.13.6
>
> --
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--
Best Regards
Masahiro Yamada
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