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Commit68cbb9f

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Modestly improve pgbench's checking for invalid ranges.
The old check against MAX_RANDOM_VALUE is clearly irrelevant sincegetrand() no longer calls random(). Instead, check whether min and maxare close enough together to avoid an overflow inside getrand(), assuggested by Tom Lane. This is still somewhat silly, because we'reusing atoi(), which doesn't check for overflow anyway and (at least onmy system) will cheerfully return 0 when given "4294967296". But that'sa problem for another commit.
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‎contrib/pgbench/pgbench.c

Lines changed: 16 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1066,9 +1066,23 @@ doCustom(TState *thread, CState *st, instr_time *conn_time, FILE *logfile)
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else
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max=atoi(argv[3]);
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1069-
if (max<min||max>MAX_RANDOM_VALUE)
1069+
if (max<min)
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{
1071-
fprintf(stderr,"%s: invalid maximum number %d\n",argv[0],max);
1071+
fprintf(stderr,"%s: maximum is less than minimum\n",argv[0]);
1072+
st->ecnt++;
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return true;
1074+
}
1075+
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/*
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* getrand() neeeds to be able to subtract max from min and add
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* one the result without overflowing. Since we know max > min,
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* we can detect overflow just by checking for a negative result.
1080+
* But we must check both that the subtraction doesn't overflow,
1081+
* and that adding one to the result doesn't overflow either.
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*/
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if (max-min<0|| (max-min)+1<0)
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{
1085+
fprintf(stderr,"%s: range too large\n",argv[0]);
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st->ecnt++;
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return true;
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}

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