[PATCH v3 0/7] lib: string: add functions to case-convert strings

Chris Metcalf cmetcalf at mellanox.com
Sun Jul 10 03:13:33 UTC 2016

On 7/8/2016 6:43 PM, Markus Mayer wrote:
> This series introduces a family of generic string case conversion
> functions. This kind of functionality is needed in several places in
> the kernel. Right now, everybody seems to be implementing their own
> copy of this functionality.
> Based on the discussion of the previous version of this series[1] and
> the use cases found in the kernel, it does look like having several
> flavours of case conversion functions is beneficial. The use cases fall
> into three categories:
>      - copying a string and converting the case while specifying a
>        maximum length to mimic strlcpy()
>      - copying a string and converting the case without specifying a
>        length to mimic strcpy()
>      - converting the case of a string in-place (i.e. modifying the
>        string that was passed in)
> Consequently, I am proposing these new functions:
>      void strlcpytoupper(char *dst, const char *src, size_t len);
>      void strlcpytolower(char *dst, const char *src, size_t len);
>      void strcpytoupper(char *dst, const char *src);
>      void strcpytolower(char *dst, const char *src);
>      void strtoupper(char *s);
>      void strtolower(char *s);

You may want to read the article here:


and follow up some of the discussion threads on LKML about the best
semantics to advertise for the strlcpy/strscpy variants.  It might be
helpful to return some kind of overflow/truncation error from your
copy functions so people can error-check the result.

Chris Metcalf, Mellanox Technologies

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