Commit cb3565b1a8b0642e7facb21392bfd24938083c7e
2025-03-07T17:59:33
keymap: Fix segfault due to invalid group wrapping The modular arithmetic is incorrect for negative values, e.g. for num_groups = 1. It triggers a segfault for the following settings: - layouts count (per key or total) N: `N > 0`, and - layout index n: `n = - k * N` (`k > 0`) % returns the *remainder* of the division, not the modulus (see C11 standard 6.5.5 “Multiplicative operators”: a % b = a - (a/b)*b. While both operators return the same result for positive operands, they do not for e.g. a negative dividend: remainder may be negative (in the open interval ]-num_groups, num_groups[) while the modulus is always positive. So if the remainder is negative, we must add `num_groups` to get the modulus. Fixes: 67b03cea ("state: correctly wrap state->locked_group and ->group") Signed-off-by: Julian Orth <ju.orth@gmail.com> Co-authored-by: Julian Orth <ju.orth@gmail.com> Co-authored-by: Pierre Le Marre <dev@wismill.eu>