Re: [OSS-Tools] [PATCH 2/8] libdt: factor out u64 sysattr parsing into helper

[Roland Hieber <rhi@pengutronix.de>]

On Fri, Jun 02, 2023 at 03:16:13PM +0200, Roland Hieber wrote:
> On Wed, May 31, 2023 at 05:22:47PM +0200, Ahmad Fatoum wrote:
> > We will need to parse two more sysattrs in a follow-up patch, so factor
> > this out for reuse. While at it switch to 64-bit strtoull: This may
> > be more useful for future users and unlike atol doesn't invoke undefined
> > behavior when parsing fails.
> > 
> > Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> > ---
> >  src/libdt.c | 42 +++++++++++++++++++++++++++++++++++-------
> >  1 file changed, 35 insertions(+), 7 deletions(-)
> > 
> > diff --git a/src/libdt.c b/src/libdt.c
> > index 2c994c647ac9..580b0b0ba769 100644
> > --- a/src/libdt.c
> > +++ b/src/libdt.c
> > @@ -2179,6 +2179,33 @@ static struct udev_device *device_find_mtd_partition(struct udev_device *dev,
> >  	return NULL;
> >  }
> >  
> > +/*
> 
> Use /** here so API doc generators could potentially  pick it up (even
> if we don't build API docs right now, but all other functions are
> documented the same way).

OK disregard that, not all functions have /** comments */ above them, so
this is a separate issue.

  - Roland

> > + * udev_device_parse_sysattr_u64 - parse sysattr value as unsigned 64-bit integer
> > + * @dev:	the udev_device to extract the attribute from
> > + * @attr:	name of the attribute to lookup
> > + * @outvalue:	returns the value parsed out of the attribute
> > + *
> > + * returns 0 for success or negative error value on failure.
> > + */
> > +static int udev_device_parse_sysattr_u64(struct udev_device *dev, const char *attr,
> > +		u64 *outvalue)
> > +{
> > +	char *endptr;
> > +	u64 value;
> > +	const char *str;
> > +
> > +	str = udev_device_get_sysattr_value(dev, attr);
> > +	if (!str)
> > +		return -EINVAL;
> > +
> > +	value = strtoull(str, &endptr, 0);
> > +	if (!*str || *endptr)
> > +		return -EINVAL;
> > +
> > +	*outvalue = value;
> > +	return 0;
> > +}
> > +
> >  /*
> >   * device_find_block_device - extract device path from udev block device
> >   *
> > @@ -2305,24 +2332,25 @@ static int udev_device_is_eeprom(struct udev_device *dev)
> >   * udev_parse_mtd - get information from a mtd udev_device
> >   * @dev:	the udev_device to extract information from
> >   * @devpath:	returns the devicepath under which the mtd device is accessible
> > - * @size:	returns the size of the mtd device
> > + * @outsize:	returns the size of the mtd device
> >   *
> >   * returns 0 for success or negative error value on failure. *devpath
> >   * will be valid on success and must be freed after usage.
> >   */
> > -static int udev_parse_mtd(struct udev_device *dev, char **devpath, size_t *size)
> > +static int udev_parse_mtd(struct udev_device *dev, char **devpath, size_t *outsize)
> >  {
> > -	const char *sizestr;
> >  	const char *outpath;
> > +	u64 size;
> > +	int ret;
> >  
> >  	if (!udev_device_is_mtd(dev))
> >  		return -EINVAL;
> >  
> > -	sizestr = udev_device_get_sysattr_value(dev, "size");
> > -	if (!sizestr)
> > -		return -EINVAL;
> > +	ret = udev_device_parse_sysattr_u64(dev, "size", &size);
> > +	if (ret)
> > +		return ret;
> >  
> > -	*size = atol(sizestr);
> > +	*outsize = size;
> >  
> >  	outpath = udev_device_get_devnode(dev);
> >  	if (!outpath)
> > -- 
> > 2.39.2
> > 
> > 
> > 
> 
> -- 
> Roland Hieber, Pengutronix e.K.          | r.hieber@pengutronix.de     |
> Steuerwalder Str. 21                     | https://www.pengutronix.de/ |
> 31137 Hildesheim, Germany                | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686         | Fax:   +49-5121-206917-5555 |
> 
> 

-- 
Roland Hieber, Pengutronix e.K.          | r.hieber@pengutronix.de     |
Steuerwalder Str. 21                     | https://www.pengutronix.de/ |
31137 Hildesheim, Germany                | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686         | Fax:   +49-5121-206917-5555 |