Messages in this thread | | | Date | Fri, 15 Oct 2021 09:29:38 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: 回复: [PATCH ] tty: vt: replace snprintf in show functions with sysfs_emit |
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On Fri, Oct 15, 2021 at 07:10:42AM +0000, 王擎 wrote: > > >> show() must not use snprintf() when formatting the value to be > >> returned to user space. > > > >Again, who is making this "must" requirement? > > > >I, as the sysfs maintainer, am not saying that all existing show > >functions MUST be converted, so I find it hard to believe that someone > >else is... > > > > According to Documentation/filesystems/sysfs.txt: > show() methods of device attributes should return the number > of bytes printed into the buffer. This is the return value of > scnprintf(). snprintf() returns the length the resulting string. > > So, show() must not use snprintf() when formatting > the value to be returned to user space.
Ok, then you need to document this _MUCH_ better, saying that the value returned by the kernel today is WRONG, and that this is a bugfix.
And can you see the difference here? Have you tested these?
> Also, use sysfs_emit directly makes more sense.
I agree, but your changelog did not mention that at all.
thanks,
greg k-h
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