Re: [PATCH v6 02/10] lib: uuid: introduce be_uuid_str_to_le_bin function

Abdellatif El Khlifi
2022-11-08T10:45:45Z

On Mon, Oct 24, 2022 at 03:07:35PM +0300, Ilias Apalodimas wrote:
> Hi Abdellatif,
>
> On Thu, Oct 13, 2022 at 11:38:49AM +0100, Abdellatif El Khlifi wrote:
> > convert big endian UUID string to little endian buffer
>
> You don't really need the be_ suffix on the declaration, endianness doesn't
> apply to strings. Can't we do something similar to uuid_str_to_bin() and
> just convert to LE?

Thanks, done in v7 [1]. Please have a look.

[1]: https://lore.kernel.org/all/20221107192055.21669-3-abdellatif.elkhlifi@arm.com/

>
> Thanks
> /Ilias
> >
> > Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > Cc: Tom Rini <trini@konsulko.com>
> > Cc: Simon Glass <sjg@chromium.org>
> > Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> > Cc: Jens Wiklander <jens.wiklander@linaro.org>
> >
> > ---
> >
> > Changelog:
> > ===============
> >
> > v4:
> >
> > * rename ffa_uuid_str_to_bin to be_uuid_str_to_le_bin and put in
> > a standalone commit (the current)
> >
> > v3:
> >
> > * introduce ffa_uuid_str_to_bin (provided by
> > arm_ffa: introduce Arm FF-A low-level driver)
> >
> > include/uuid.h | 8 +++++++
> > lib/uuid.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 72 insertions(+)
> >
> > diff --git a/include/uuid.h b/include/uuid.h
> > index 4a4883d3b5..ad3af350f9 100644
> > --- a/include/uuid.h
> > +++ b/include/uuid.h
> > @@ -2,6 +2,8 @@
> > /*
> > * Copyright (C) 2014 Samsung Electronics
> > * Przemyslaw Marczak <p.marczak@samsung.com>
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > */
> > #ifndef __UUID_H__
> > #define __UUID_H__
> > @@ -44,4 +46,10 @@ int uuid_guid_get_bin(const char *guid_str, unsigned char *guid_bin);
> > const char *uuid_guid_get_str(const unsigned char *guid_bin);
> > void gen_rand_uuid(unsigned char *uuid_bin);
> > void gen_rand_uuid_str(char *uuid_str, int str_format);
> > +
> > +/**
> > + * be_uuid_str_to_le_bin - Converts a big endian UUID string to a little endian buffer
> > + */
> > +int be_uuid_str_to_le_bin(const char *uuid_str, unsigned char *uuid_bin);
> > +
> > #endif
> > diff --git a/lib/uuid.c b/lib/uuid.c
> > index 465e1ac38f..15a9ab49d5 100644
> > --- a/lib/uuid.c
> > +++ b/lib/uuid.c
> > @@ -1,6 +1,8 @@
> > // SPDX-License-Identifier: GPL-2.0+
> > /*
> > * Copyright 2011 Calxeda, Inc.
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi@arm.com>
> > */
> >
> > #include <common.h>
> > @@ -346,6 +348,68 @@ int uuid_str_to_bin(const char *uuid_str, unsigned char *uuid_bin,
> > return 0;
> > }
> >
> > +/**
> > + * be_uuid_str_to_le_bin - Converts a big endian UUID string to a little endian buffer
> > + * @uuid_str: UUID string in big endian format (36 bytes wide + '/0')
> > + * @uuid_bin: preallocated 16 bytes UUID buffer in little endian format
> > + *
> > + * UUID string is 36 characters (36 bytes):
> > + *
> > + * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
> > + * be be be be be
> > + *
> > + * where x is a hexadecimal character. Fields are separated by '-'s.
> > + * When converting to a binary UUID, these endianness rules apply:
> > + * be: means the field in the string is considered a big endian hex number
> > + * and should be converted to little endian binary format
> > + *
> > + * Return:
> > + *
> > + * uuid_bin filled with little endian UUID data
> > + * On success 0 is returned. Otherwise, failure code.
> > + */
> > +int be_uuid_str_to_le_bin(const char *uuid_str, unsigned char *uuid_bin)
> > +{
> > + u16 tmp16 = 0;
> > + u32 tmp32 = 0;
> > + u64 tmp64 = 0;
> > +
> > + if (!uuid_str_valid(uuid_str) || !uuid_bin)
> > + return -EINVAL;
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp32 = simple_strtoul(uuid_str, NULL, 16);
> > + memcpy(uuid_bin, &tmp32, 4);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp16 = simple_strtoul(uuid_str + 9, NULL, 16);
> > + memcpy(uuid_bin + 4, &tmp16, 2);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp16 = simple_strtoul(uuid_str + 14, NULL, 16);
> > + memcpy(uuid_bin + 6, &tmp16, 2);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp16 = simple_strtoul(uuid_str + 19, NULL, 16);
> > + memcpy(uuid_bin + 8, &tmp16, 2);
> > +
> > + /*
> > + * reverse bytes from big to little endian
> > + */
> > + tmp64 = simple_strtoull(uuid_str + 24, NULL, 16);
> > + memcpy(uuid_bin + 10, (char *)&tmp64, 6);
> > +
> > + return 0;
> > +}
> > +
> > /*
> > * uuid_bin_to_str() - convert big endian binary data to string UUID or GUID.
> > *
> > --
> > 2.17.1
> >