vsprintf: add infrastructure support for extended '%p' specifiers
This expands the kernel '%p' handling with an arbitrary alphanumberic specifier extension string immediately following the '%p'. Right now it's just being ignored, but the next commit will start adding some specific pointer type extensions. NOTE! The reason the extension is appended to the '%p' is to allow minimal gcc type checking: gcc will still see the '%p' and will check that the argument passed in is indeed a pointer, and yet will not complain about the extended information that gcc doesn't understand about (on the other hand, it also won't actually check that the pointer type and the extension are compatible). Alphanumeric characters were chosen because there is no sane existing use for a string format with a hex pointer representation immediately followed by alphanumerics (which is what such a format string would have traditionally resulted in). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 changed files with 14 additions and 2 deletions
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@ -511,7 +511,14 @@ static char *string(char *buf, char *end, char *s, int field_width, int precisio
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return buf;
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}
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static char *pointer(char *buf, char *end, void *ptr, int field_width, int precision, int flags)
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/*
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* Show a '%p' thing. A kernel extension is that the '%p' is followed
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* by an extra set of alphanumeric characters that are extended format
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* specifiers.
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*
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* Right now don't actually handle any such, but we will..
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*/
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static char *pointer(const char *fmt, char *buf, char *end, void *ptr, int field_width, int precision, int flags)
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{
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flags |= SMALL;
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if (field_width == -1) {
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@ -663,7 +670,12 @@ int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
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continue;
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case 'p':
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str = pointer(str, end, va_arg(args, void *), field_width, precision, flags);
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str = pointer(fmt+1, str, end,
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va_arg(args, void *),
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field_width, precision, flags);
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/* Skip all alphanumeric pointer suffixes */
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while (isalnum(fmt[1]))
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fmt++;
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continue;
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case 'n':
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