btrfs: sysfs: Use scnprintf() instead of snprintf()
snprintf() is a hard-to-use function, and it's especially difficult to use it properly for concatenating substrings in a buffer with a limited size. Since snprintf() returns the would-be-output size, not the actual size, the subsequent use of snprintf() may point to the incorrect position easily. Also, returning the value from snprintf() directly to sysfs show function would pass a bogus value that is higher than the actually truncated string. That said, although the current code doesn't actually overflow the buffer with PAGE_SIZE, it's a usage that shouldn't be done. Or it's worse; this gives a wrong confidence as if it were doing safe operations. This patch replaces such snprintf() calls with a safer version, scnprintf(). It returns the actual output size, hence it's more intuitive and the code does what's expected. Signed-off-by:Takashi Iwai <tiwai@suse.de> Reviewed-by:
David Sterba <dsterba@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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39dba873
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