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Matthias Goergens
292fb23a92
xentop parses -d/--delay and -i/--iterations with atoi(), so invalid input is silently accepted with surprising results: a fractional delay such as "-d 2.5" is truncated to 2; "-d abc" parses as 0, which in batch mode turns the output loop into a busy loop; "-d -1" wraps to an effective delay of about 136 years; and "-i 0" (or any unparsable iterations count) decrements an unsigned counter from zero, running for about 2^32 iterations. atoi() also has undefined behaviour on out-of-range input. Parse both options with strtoull() instead, and reject anything that is not a plain decimal integer in range: a sign, a fractional part, trailing junk or overflow now produce an error and exit rather than a silently wrong value. Compatibility considerations: "--delay 0" remains accepted, since updating as fast as possible is a plausible deliberate choice and works today; "--iterations 0" is rejected, since running the loop 2^32 times cannot be what the caller meant. The interactive 'D' prompt already validates its input and is unchanged. The only previously useful invocation this breaks is a fractional delay, which now fails loudly instead of silently rounding down - which is the point of the change. A patch documenting the --delay truncation was posted in 2010 but never applied: Link: https://lore.kernel.org/xen-devel/01ea26d2420e3562eb30.1292604768@chilopoda.uk.xensource.com/ Signed-off-by: Matthias Goergens <matthias.goergens@gmail.com> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>