[ntpsec commit] Make sprintb() in util/ntptime safe and re-entrant.

[Eric S. Raymond]

Module:    ntpsec
Branch:    master
Commit:    309f9bc277aa8d3a177b8a93ad07db501c00ec20
Changeset: http://git.ntpsec.org/ntpsec/commit/?id=309f9bc277aa8d3a177b8a93ad07db501c00ec20

Author:    Eric S. Raymond <esr at thyrsus.com>
Date:      Sun Oct 18 06:07:30 2015 -0400

Make sprintb() in util/ntptime safe and re-entrant.

Eventually we'll have more uses for it.

---

 devel-docs/TODO |  5 ++---
 util/ntptime.c  | 18 +++++++++++-------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/devel-docs/TODO b/devel-docs/TODO
index 6eea9d6..7b524b6 100644
--- a/devel-docs/TODO
+++ b/devel-docs/TODO
@@ -146,9 +146,8 @@ they are salvageable.
 * seccomp sandboxing fails to build under Ubuntu due to some confusion
   in the Linux headers.  Investigate.
 
-* Adapt BSD snprintb into a better dumper for flag words like flash
-  codes (throwing out the old-format support) and use it
-  systematically to make reports more readable.
+* Use the snprintb in util/ntptime for flag words like flash
+  codes and use it systematically to make reports more readable.
 
 * Timer events need, as much as possible, to be eliminated - they eat
   power on laptops and mobile devices, usually unnecessarily.  At least
diff --git a/util/ntptime.c b/util/ntptime.c
index e1b2895..44907b3 100644
--- a/util/ntptime.c
+++ b/util/ntptime.c
@@ -49,7 +49,7 @@
 /*
  * Function prototypes
  */
-const char *	sprintb		(u_int, const char *);
+const char *	snprintb	(size_t, char *, u_int, const char *);
 const char *	timex_state	(int);
 
 #ifdef SIGSYS
@@ -324,6 +324,7 @@ main(
 		   "Must be root to set kernel values\nntp_adjtime() call fails" :
 		   "ntp_adjtime() call fails");
 	} else {
+		char binbuf[132];
 		/* oldstyle formats */
 		char *ofmt7 = "ntp_adjtime() returns code %d (%s)\n";
 		char *ofmt8 = "  modes %s,\n";
@@ -347,7 +348,8 @@ main(
 
 		flash = ntx.status;
 		printf(json ? jfmt7 : ofmt7, status, timex_state(status));
-		printf(json ? jfmt8 : ofmt8, sprintb(ntx.modes, TIMEX_MOD_BITS));
+		printf(json ? jfmt8 : ofmt8,
+		       snprintb(sizeof(binbuf), binbuf, ntx.modes, TIMEX_MOD_BITS));
 		ftemp = (double)ntx.offset;
 #ifdef STA_NANO
 		if (flash & STA_NANO)
@@ -359,7 +361,8 @@ main(
 		printf(json ? jfmt11 : ofmt11,
 		     (u_long)ntx.maxerror, (u_long)ntx.esterror);
 		printf(json ? jfmt12 : ofmt12,
-		       sprintb((u_int)ntx.status, TIMEX_STA_BITS));
+		       snprintb(sizeof(binbuf), binbuf,
+			       (u_int)ntx.status, TIMEX_STA_BITS));
 		ftemp = (double)ntx.tolerance / SCALE_FREQ;
 		gtemp = (double)ntx.precision;
 #ifdef STA_NANO
@@ -421,7 +424,9 @@ pll_trap(
  * Print a value a la the %b format of the kernel's printf
  */
 const char *
-sprintb(
+snprintb(
+	size_t		buflen,
+	char *		buf,
 	u_int		v,
 	const char *	bits
 	)
@@ -431,12 +436,11 @@ sprintb(
 	int i;
 	bool any;
 	char c;
-	static char buf[132];
 
 	if (bits != NULL && *bits == 8)
-		snprintf(buf, sizeof(buf), "0%o", v);
+		snprintf(buf, buflen, "0%o", v);
 	else
-		snprintf(buf, sizeof(buf), "0x%x", v);
+		snprintf(buf, buflen, "0x%x", v);
 	cp = buf + strlen(buf);
 	cplim = buf + sizeof(buf);
 	if (bits != NULL) {