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

[Abdellatif El Khlifi]

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 at arm.com>
> > Cc: Tom Rini <trini at konsulko.com>
> > Cc: Simon Glass <sjg at chromium.org>
> > Cc: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > Cc: Jens Wiklander <jens.wiklander at 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 at samsung.com>
> > + * (C) Copyright 2022 ARM Limited
> > + * Abdellatif El Khlifi <abdellatif.elkhlifi at 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 at 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
> >