Add a validbcd() routine that uses the bcd2bin_data[] array and returns a
bool indicating whether the input value represents a valid BCD byte. The existing bcd2bin() routine will KASSERT if asked to convert a bad value, but sometimes the kernel has to handle BCD data from untrusted sources, so this will provide a mechanism to validate data before attempting conversion. This would be have easier/cleaner if the bcd2bin_data[] array contained an out-of-range value (such as 0xff) in the infill locations that aren't valid, but it's a global symbol that might be referenced by out-of-tree code relying on the current scheme, so I'm leaving that alone.
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=327453
@ -354,6 +354,7 @@ extern char const hex2ascii_data[];
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#define bcd2bin(bcd) (bcd2bin_data[bcd])
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#define bin2bcd(bin) (bin2bcd_data[bin])
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#define hex2ascii(hex) (hex2ascii_data[hex])
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#define validbcd(bcd) (bcd == 0 || (bcd > 0 && bcd <= 0x99 && bcd2bin_data[bcd] != 0))
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/* min/max (undocumented) */
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static __inline int imax(int a, int b) { return (a > b ? a : b); }
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@ -82,6 +82,13 @@ hex2ascii(int hex)
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return (hex2ascii_data[hex]);
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}
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static inline bool
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validbcd(int bcd)
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{
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return (bcd == 0 || (bcd > 0 && bcd <= 0x99 && bcd2bin_data[bcd] != 0));
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}
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static __inline int imax(int a, int b) { return (a > b ? a : b); }
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static __inline int imin(int a, int b) { return (a < b ? a : b); }
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static __inline long lmax(long a, long b) { return (a > b ? a : b); }
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