Hello,
jot(1) appears to give unsatisfying randomness when used
with larger numbers (and -r):
# (before diff)
% jot -r 10 1000000000 9999999999
1294196288
1351335130
1105868309
1082237294
1078729542
1009152305
1108537886
1362127442
1071708731
1402965187
That is because in jot.c we see:
249 uint32_t uintx = 0; /* Initialized to make gcc happy. */
...
272 uintx = pow10 * (ender - begin);
273 if (uintx >= UINT32_MAX)
274 errx(1, "requested range too large");
...
Later on uintx is used like this:
...
283 y = arc4random_uniform(uintx) / (double)pow10;
...
Changing uintx to double fixes the issue for me (the error-condition
triggers) and it passes the tests in regress/usr.bin/jot, however
may not be the proper fix.
#(after diff)
% jot -r 10 1000000000 9999999999
jot: requested range too large
Alf
Index: usr.bin/jot/jot.c
===================================================================
RCS file: /cvs/src/usr.bin/jot/jot.c,v
retrieving revision 1.49
diff -u -p -r1.49 jot.c
--- usr.bin/jot/jot.c 27 Jun 2019 18:03:36 -0000 1.49
+++ usr.bin/jot/jot.c 29 Jul 2021 09:12:22 -0000
@@ -246,7 +246,7 @@ main(int argc, char *argv[])
} else { /* Random output: use defaults for omitted values. */
bool use_unif;
uint32_t pow10 = 1;
- uint32_t uintx = 0; /* Initialized to make gcc happy. */
+ double uintx = 0; /* Initialized to make gcc happy. */
if (prec > 9) /* pow(10, prec) > UINT32_MAX */
errx(1, "requested precision too large");
