[Git][NTPsec/ntpsec][master] Forward-port from Classic: [Bug 2772] adj_systime overflows tv_usec

[Eric S. Raymond]

Eric S. Raymond pushed to branch master at NTPsec / ntpsec


Commits:
f6c75ecc by Juergen Perlinger at 2016-03-20T16:34:39-04:00
Forward-port from Classic: [Bug 2772] adj_systime overflows tv_usec

- - - - -


1 changed file:

- libntp/systime.c


Changes:

=====================================
libntp/systime.c
=====================================
--- a/libntp/systime.c
+++ b/libntp/systime.c
@@ -312,9 +312,18 @@ adj_systime(
 	else
 		quant = 1e-6;
 	ticks = (long)(dtemp / quant + .5);
-	adjtv.tv_usec = (long)(ticks * quant * 1e6);
-	dtemp -= adjtv.tv_usec / 1e6;
-	sys_residual = dtemp;
+	adjtv.tv_usec = (long)(ticks * quant * 1.e6 + .5);
+	/* The rounding in the conversions could us push over the
+	 * limits: make sure the result is properly normalised!
+	 * note: sign comes later, all numbers non-negative here.
+	 */
+	if (adjtv.tv_usec >= 1000000) {
+		adjtv.tv_sec  += 1;
+		adjtv.tv_usec -= 1000000;
+		dtemp         -= 1.;
+	}
+	/* set the new residual with leftover from correction */
+	sys_residual = dtemp - adjtv.tv_usec * 1.e-6;
 
 	/*
 	 * Convert to signed seconds and microseconds for the Unix



View it on GitLab: https://gitlab.com/NTPsec/ntpsec/commit/f6c75eccfe9a2e2d7a9bc56063768e5d3d4ed590
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