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From: "Namjae Jeon" <namjae.jeon@samsung.com>
To: "'Pali Rohár'" <pali.rohar@gmail.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-fsdevel@vger.kernel.org>,
	<gregkh@linuxfoundation.org>, <valdis.kletnieks@vt.edu>,
	<hch@lst.de>, <sj1557.seo@samsung.com>, <linkinjeon@gmail.com>
Subject: RE: [PATCH v9 10/13] exfat: add nls operations
Date: Fri, 10 Jan 2020 07:35:47 +0900	[thread overview]
Message-ID: <001401d5c73d$2349f6c0$69dde440$@samsung.com> (raw)
In-Reply-To: <20200103123114.vm23vqag5dbry2mu@pali>

> What about just filtering two u16 (one surrogate pair)? Existing NLS
> modules do not support code points above U+FFFF so two u16 (one
> surrogate pair) just needs to be converted to one replacement character.
Hi Pali,

You're right.
> 
> diff --git a/fs/exfat/nls.c b/fs/exfat/nls.c
> index 81d75aed9..f626a0a89 100644
> --- a/fs/exfat/nls.c
> +++ b/fs/exfat/nls.c
> @@ -545,7 +545,10 @@ static int __exfat_nls_vfsname_to_utf16s(struct
> super_block *sb,
>  	return unilen;
>  }
> 
> -static int __exfat_nls_uni16s_to_vfsname(struct super_block *sb,
> +#define SURROGATE_PAIR		0x0000d800
> +#define SURROGATE_LOW		0x00000400
> +
> +static int __exfat_nls_utf16s_to_vfsname(struct super_block *sb,
>  		struct exfat_uni_name *p_uniname, unsigned char *p_cstring,
>  		int buflen)
>  {
> @@ -559,7 +562,23 @@ static int __exfat_nls_uni16s_to_vfsname(struct
> super_block *sb,
>  		if (*uniname == '\0')
>  			break;
> 
> -		len = exfat_convert_uni_to_ch(nls, *uniname, buf, NULL);
> +		if ((*uniname & SURROGATE_MASK) != SURROGATE_PAIR) {
> +			len = exfat_convert_uni_to_ch(nls, *uniname, buf,
> NULL);
> +		} else {
> +			/* Process UTF-16 surrogate pair as one character */
> +			if (!(*uniname & SURROGATE_LOW) && i+1 <
> MAX_NAME_LENGTH &&
> +			    (*(uniname+1) & SURROGATE_MASK) == SURROGATE_PAIR
> &&
> +			    (*(uniname+1) & SURROGATE_LOW)) {
> +				uniname++;
> +				i++;
> +			}
> +			/* UTF-16 surrogate pair encodes code points above
> Ux+FFFF.
> +			 * Code points above U+FFFF are not supported by
> kernel NLS
> +			 * framework therefore use replacement character */
> +			len = 1;
> +			buf[0] = '_';
> +		}
> +
>  		if (out_len + len >= buflen)
>  			len = buflen - 1 - out_len;
>  		out_len += len;
> @@ -623,7 +642,7 @@ int exfat_nls_uni16s_to_vfsname(struct super_block *sb,
>  	if (EXFAT_SB(sb)->options.utf8)
>  		return __exfat_nls_utf16s_to_vfsname(sb, uniname, p_cstring,
>  				buflen);
> -	return __exfat_nls_uni16s_to_vfsname(sb, uniname, p_cstring,
> buflen);
> +	return __exfat_nls_utf16s_to_vfsname(sb, uniname, p_cstring,
> buflen);
>  }
> 
>  int exfat_nls_vfsname_to_uni16s(struct super_block *sb,
> 
> I have not tested this code, it is just an idea how to quick & dirty
> solve this problem that NLS framework works with UCS-2 encoding and
> UCS-4/UTF-32 or UTF-16.
I will check and test this code.
Thanks for your suggestion.


  reply	other threads:[~2020-01-09 22:36 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20200102082359epcas1p2aa1eca9729a6ec54ec3b8140615dca6e@epcas1p2.samsung.com>
2020-01-02  8:20 ` [PATCH v9 00/13] add the latest exfat driver Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 01/13] exfat: add in-memory and on-disk structures and headers Namjae Jeon
2020-01-08 17:08     ` Christoph Hellwig
2020-01-09 22:43       ` Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 02/13] exfat: add super block operations Namjae Jeon
2020-01-08 17:21     ` Christoph Hellwig
2020-01-09 23:21       ` Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 03/13] exfat: add inode operations Namjae Jeon
2020-01-08 17:50     ` Christoph Hellwig
2020-01-09 23:23       ` Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 04/13] exfat: add directory operations Namjae Jeon
2020-01-08 17:52     ` Christoph Hellwig
2020-01-02  8:20   ` [PATCH v9 05/13] exfat: add file operations Namjae Jeon
2020-01-08 17:56     ` Christoph Hellwig
2020-01-02  8:20   ` [PATCH v9 06/13] exfat: add exfat entry operations Namjae Jeon
2020-01-08 18:00     ` Christoph Hellwig
2020-01-09 23:24       ` Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 07/13] exfat: add bitmap operations Namjae Jeon
2020-01-08 18:01     ` Christoph Hellwig
2020-01-02  8:20   ` [PATCH v9 08/13] exfat: add exfat cache Namjae Jeon
2020-01-08 18:02     ` Christoph Hellwig
2020-01-02  8:20   ` [PATCH v9 09/13] exfat: add misc operations Namjae Jeon
2020-01-02  9:19     ` Pali Rohár
2020-01-02 11:30       ` Namjae Jeon
2020-01-02 11:40         ` Pali Rohár
2020-01-03 18:36           ` Pali Rohár
2020-01-03 23:28             ` Namjae Jeon
2020-01-08 18:03       ` Christoph Hellwig
2020-01-08 19:40         ` Arnd Bergmann
2020-01-09 23:32           ` Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 10/13] exfat: add nls operations Namjae Jeon
2020-01-02 13:55     ` Pali Rohár
2020-01-03  7:06       ` Namjae Jeon
2020-01-03  8:44         ` Pali Rohár
2020-01-02 14:20     ` Pali Rohár
2020-01-03  4:44       ` Namjae Jeon
2020-01-03  9:40     ` Pali Rohár
2020-01-03 12:31       ` Pali Rohár
2020-01-09 22:35         ` Namjae Jeon [this message]
2020-01-05 15:24     ` Pali Rohár
2020-01-05 16:51     ` Pali Rohár
2020-01-06 19:46       ` Gabriel Krisman Bertazi
2020-01-07 11:52         ` Pali Rohár
2020-01-09 22:04           ` [PATCH v9 09/13] exfat: add misc operations Valdis Klētnieks
2020-01-09 23:41             ` Namjae Jeon
2020-01-09 22:37       ` [PATCH v9 10/13] exfat: add nls operations Namjae Jeon
2020-01-02  8:20   ` [PATCH v9 11/13] exfat: add Kconfig and Makefile Namjae Jeon
2020-01-02 12:53     ` Pali Rohár
2020-01-02  8:20   ` [PATCH v9 12/13] exfat: add exfat in fs/Kconfig and fs/Makefile Namjae Jeon
2020-01-02 12:58     ` Pali Rohár
2020-01-02 13:07       ` Namjae Jeon
2020-01-02 13:10         ` Pali Rohár
2020-01-02 14:19         ` Greg KH
2020-01-02 23:48           ` Namjae Jeon
2020-01-04  5:22     ` kbuild test robot
2020-01-02  8:20   ` [PATCH v9 13/13] MAINTAINERS: add exfat filesystem Namjae Jeon

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