On Sun, Mar 03, 2019 at 06:47:32PM +0100, Heiner Kallweit wrote: > I submitted this through the netdev tree, maybe relevant for you as well. > See also here: https://marc.info/?t=155103900100003&r=1&w=2 > > -------- Forwarded Message -------- > Subject: [PATCH net-next 1/2] lib: string: add strreplace_nonalnum > Date: Sun, 3 Mar 2019 18:20:50 +0100 > From: Heiner Kallweit <[email protected]> > To: Florian Fainelli <[email protected]>, Andrew Lunn <[email protected]>, > David Miller <[email protected]> > CC: [email protected] <[email protected]> > > Add a new function strreplace_nonalnum that replaces all > non-alphanumeric characters. Such functionality is needed e.g. when a > string is supposed to be used in a sysfs file name. If '\0' is given > as new character then non-alphanumeric characters are cut.
sysfs doesn't have any such requirements, it can use whatever you want to give it for a filename. So don't create a random kernel function for sysfs please. > > Signed-off-by: Heiner Kallweit <[email protected]> > --- > include/linux/string.h | 1 + > lib/string.c | 27 +++++++++++++++++++++++++++ > 2 files changed, 28 insertions(+) > > diff --git a/include/linux/string.h b/include/linux/string.h > index 7927b875f..d827b0b0f 100644 > --- a/include/linux/string.h > +++ b/include/linux/string.h > @@ -169,6 +169,7 @@ static inline void memcpy_flushcache(void *dst, const > void *src, size_t cnt) > #endif > void *memchr_inv(const void *s, int c, size_t n); > char *strreplace(char *s, char old, char new); > +char *strreplace_nonalnum(char *s, char new); > > extern void kfree_const(const void *x); > > diff --git a/lib/string.c b/lib/string.c > index 38e4ca08e..f2b1baf96 100644 > --- a/lib/string.c > +++ b/lib/string.c > @@ -1047,6 +1047,33 @@ char *strreplace(char *s, char old, char new) > } > EXPORT_SYMBOL(strreplace); > > +/** > + * strreplace_nonalnum - Replace all non-alphanumeric characters in a string. > + * @s: The string to operate on. > + * @new: The character non-alphanumeric characters are replaced with. > + * > + * If new is '\0' then non-alphanumeric characters are cut. > + * > + * Returns pointer to the nul byte at the end of the modified string. Why do you need to point to the end of the string? > + */ > +char *strreplace_nonalnum(char *s, char new) > +{ > + char *p = s; > + > + for (; *s; ++s) > + if (isalnum(*s)) { > + if (p != s) > + *p = *s; > + ++p; > + } else if (new) { > + *p++ = new; > + } > + *p = '\0'; No max length? No error checking? Surely we can do better, see the long thread on the kernel-hardnening list about string functions please. greg k-h
