On Sun, Jan 16, 2022 at 04:14:35PM +0100, Heinrich Schuchardt wrote:
> In different places text representations are used for GUIDs, e.g.
>
> * command efidebug
> * command part list for GPT partitions
>
> To allow reducing code duplication introduce a new printf code %pUs.
> It will call uuid_guid_get_str() to get a text representation. If none is
> found it will fallback to %pUl and print a hexadecimal representation.
I think the idea is good.
Moreover, when you add a new format specifier to printf() routine,
it would also be good to add a document so that people won't bustle
around the code to find an appropriate format string.
Not only to "%pU*", but also others including "%pD" and "%ls" that you added.
# See linux's Documentation/core-api/printk-formats.rst.
-Takahiro Akashi
> Signed-off-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
> ---
> lib/vsprintf.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index de9f236b90..2c0cc1647e 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -255,8 +255,8 @@ static char *number(char *buf, char *end, u64 num,
> return buf;
> }
>
> -static char *string(char *buf, char *end, char *s, int field_width,
> - int precision, int flags)
> +static char *string(char *buf, char *end, const char *s, int field_width,
> + int precision, int flags)
> {
> int len, i;
>
> @@ -387,12 +387,14 @@ static char *ip4_addr_string(char *buf, char *end, u8
> *addr, int field_width,
> * %pUB: 01020304-0506-0708-090A-0B0C0D0E0F10
> * %pUl: 04030201-0605-0807-090a-0b0c0d0e0f10
> * %pUL: 04030201-0605-0807-090A-0B0C0D0E0F10
> + * %pUs: GUID text representation if known or fallback to %pUl
> */
> static char *uuid_string(char *buf, char *end, u8 *addr, int field_width,
> int precision, int flags, const char *fmt)
> {
> char uuid[UUID_STR_LEN + 1];
> int str_format;
> + const char *str;
>
> switch (*(++fmt)) {
> case 'L':
> @@ -404,6 +406,13 @@ static char *uuid_string(char *buf, char *end, u8 *addr,
> int field_width,
> case 'B':
> str_format = UUID_STR_FORMAT_STD | UUID_STR_UPPER_CASE;
> break;
> + case 's':
> + str = uuid_guid_get_str(addr);
> + if (str)
> + return string(buf, end, str,
> + field_width, precision, flags);
> + str_format = UUID_STR_FORMAT_GUID;
> + break;
> default:
> str_format = UUID_STR_FORMAT_STD;
> break;
> --
> 2.33.1
>
