640 number_to_scaled_string is duplicated in several commands

Reviewed by: Sebastian Wiedenroth <wiedi@frubar.net>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Yuri Pankov <yuripv@gmx.com>
Approved by: Dan McDonald <danmcd@joyent.com>

22 files changed, 421 insertions, 633 deletions

diff --git a/usr/src/cmd/beadm/Makefile b/usr/src/cmd/beadm/Makefile
index 8ea7ac8cae..e19adc52bc 100644
--- a/usr/src/cmd/beadm/Makefile
+++ b/usr/src/cmd/beadm/Makefile
@@ -30,7 +30,7 @@ POFILE=		beadm.po
 
 include ../Makefile.cmd
 
-LDLIBS += -lnvpair -lbe
+LDLIBS += -lnvpair -lbe -lcmdutils
 CERRWARN += -_gcc=-Wno-parentheses
 
 $(NOT_RELEASE_BUILD)CPPFLAGS += -DDEBUG
diff --git a/usr/src/cmd/beadm/beadm.c b/usr/src/cmd/beadm/beadm.c
index 00073ae717..3667c762a4 100644
--- a/usr/src/cmd/beadm/beadm.c
+++ b/usr/src/cmd/beadm/beadm.c
@@ -25,6 +25,7 @@
  * Copyright 2015 Toomas Soome <tsoome@me.com>
  * Copyright 2015 Gary Mills
  * Copyright (c) 2015 by Delphix. All rights reserved.
+ * Copyright 2017 Jason King
  */
 
 /*
@@ -40,6 +41,8 @@
 #include <stdlib.h>
 #include <wchar.h>
 #include <sys/types.h>
+#include <sys/debug.h>
+#include <libcmdutils.h>
 
 #include "libbe.h"
 
@@ -55,6 +58,7 @@
 
 #define	DT_BUF_LEN (128)
 #define	NUM_COLS (6)
+CTASSERT(DT_BUF_LEN >= NN_NUMBUF_SZ);
 
 static int be_do_activate(int argc, char **argv);
 static int be_do_create(int argc, char **argv);
@@ -249,32 +253,6 @@ init_hdr_cols(enum be_fmt be_fmt, struct hdr_info *hdr)
 }
 
 static void
-nicenum(uint64_t num, char *buf, size_t buflen)
-{
-	uint64_t n = num;
-	int index = 0;
-	char u;
-
-	while (n >= 1024) {
-		n /= 1024;
-		index++;
-	}
-
-	u = " KMGTPE"[index];
-
-	if (index == 0) {
-		(void) snprintf(buf, buflen, "%llu", n);
-	} else {
-		int i;
-		for (i = 2; i >= 0; i--) {
-			if (snprintf(buf, buflen, "%.*f%c", i,
-			    (double)num / (1ULL << 10 * index), u) <= 5)
-				break;
-		}
-	}
-}
-
-static void
 count_widths(enum be_fmt be_fmt, struct hdr_info *hdr, be_node_list_t *be_nodes)
 {
 	size_t len[NUM_COLS];
diff --git a/usr/src/cmd/du/du.c b/usr/src/cmd/du/du.c
index 3911135b50..24ca7aca50 100644
--- a/usr/src/cmd/du/du.c
+++ b/usr/src/cmd/du/du.c
@@ -22,6 +22,7 @@
  * Copyright 2017 OmniTI Computer Consulting, Inc.  All rights reserved.
  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
+ * Copyright 2017 Jason King
  */
 
 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
@@ -66,9 +67,6 @@ static char		*name;
 static size_t		base_len = PATH_MAX + 1;    /* # of chars for base */
 static size_t		name_len = PATH_MAX + 1;    /* # of chars for name */
 
-#define	NUMBER_WIDTH	64
-typedef char		numbuf_t[NUMBER_WIDTH];
-
 /*
  * Output formats. illumos uses a tab as separator, XPG4 a space.
  */
@@ -528,75 +526,6 @@ descend(char *curname, int curfd, int *retcode, dev_t device)
 		return (blocks);
 }
 
-/*
- * Convert an unsigned long long to a string representation and place the
- * result in the caller-supplied buffer.
- * The given number is in units of "unit_from" size,
- * this will first be converted to a number in 1024 or 1000 byte size,
- * depending on the scaling factor.
- * Then the number is scaled down until it is small enough to be in a good
- * human readable format i.e. in the range 0 thru scale-1.
- * If it's smaller than 10 there's room enough to provide one decimal place.
- * The value "(unsigned long long)-1" is a special case and is always
- * converted to "-1".
- * Returns a pointer to the caller-supplied buffer.
- */
-static char *
-number_to_scaled_string(
-	numbuf_t buf,			/* put the result here */
-	unsigned long long number,	/* convert this number */
-	unsigned long long unit_from,	/* number of bytes per input unit */
-	unsigned long long scale)	/* 1024 (-h)  or 1000 (-H) */
-{
-	unsigned long long save = 0;
-	char *M = "KMGTPE"; /* Measurement: kilo, mega, giga, tera, peta, exa */
-	char *uom = M;    /* unit of measurement, initially 'K' (=M[0]) */
-
-	if ((long long)number == (long long)-1) {
-		(void) strcpy(buf, "-1");
-		return (buf);
-	}
-
-	/*
-	 * Convert number from unit_from to given scale (1024 or 1000)
-	 * This means multiply number with unit_from and divide by scale.
-	 * if number is large enough, we first divide and then multiply
-	 * 	to avoid an overflow
-	 * 	(large enough here means 100 (rather arbitrary value)
-	 *	times scale in order to reduce rounding errors)
-	 * otherwise, we first multiply and then divide
-	 * 	to avoid an underflow
-	 */
-	if (number >= 100L * scale) {
-		number = number / scale;
-		number = number * unit_from;
-	} else {
-		number = number * unit_from;
-		number = number / scale;
-	}
-
-	/*
-	 * Now we have number as a count of scale units.
-	 * Stop scaling when we reached exa bytes, then something is
-	 * probably wrong with our number.
-	 */
-	while ((number >= scale) && (*uom != 'E')) {
-		uom++; /* next unit of measurement */
-		save = number;
-		number = (number + (scale / 2)) / scale;
-	}
-
-	/* check if we should output a decimal place after the point */
-	if (save && ((save / scale) < 10)) {
-		/* sprintf() will round for us */
-		float fnum = (float)save / scale;
-		(void) sprintf(buf, "%4.1f%c", fnum, *uom);
-	} else {
-		(void) sprintf(buf, "%4llu%c", number, *uom);
-	}
-	return (buf);
-}
-
 static void
 printsize(blkcnt_t blocks, char *path)
 {
@@ -605,11 +534,10 @@ printsize(blkcnt_t blocks, char *path)
 	bsize = Aflg ? 1 : DEV_BSIZE;
 
 	if (hflg) {
-		numbuf_t numbuf;
-		unsigned long long scale = 1024L;
-		(void) printf(FORMAT1,
-		    number_to_scaled_string(numbuf, blocks, bsize, scale),
-		    path);
+	char buf[NN_NUMBUF_SZ] = { 0 };
+
+	nicenum_scale(blocks, bsize, buf, sizeof (buf), 0);
+	(void) printf(FORMAT1, buf, path);
 	} else if (kflg) {
 		(void) printf(FORMAT2, (long long)kb(blocks), path);
 	} else if (mflg) {
diff --git a/usr/src/cmd/fs.d/Makefile b/usr/src/cmd/fs.d/Makefile
index 3c36817494..2f5bd31ec7 100644
--- a/usr/src/cmd/fs.d/Makefile
+++ b/usr/src/cmd/fs.d/Makefile
@@ -87,6 +87,7 @@ CERRWARN += -_gcc=-Wno-unused-variable
 CERRWARN += -_gcc=-Wno-uninitialized
 CERRWARN += -_gcc=-Wno-unused-function
 
+$(DFPROG) :=	LDLIBS += -lcmdutils
 $(SPPROG) :=	LDLIBS += -lkstat
 
 $(ROOTETCMNTTAB) := FILEMODE = 444
diff --git a/usr/src/cmd/fs.d/df.c b/usr/src/cmd/fs.d/df.c
index 3ba4aeb832..ee7bf6e7d5 100644
--- a/usr/src/cmd/fs.d/df.c
+++ b/usr/src/cmd/fs.d/df.c
@@ -26,6 +26,9 @@
  * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
  */
 
+/*
+ * Copyright 2016 Jason King
+ */
 
 #include <dlfcn.h>
 #include <stdio.h>
@@ -48,7 +51,9 @@
 #include <sys/mkdev.h>
 #include <sys/int_limits.h>
 #include <sys/zone.h>
+#include <sys/debug.h>
 #include <libzfs.h>
+#include <libcmdutils.h>
 
 #include "fslib.h"
 
@@ -134,6 +139,7 @@ extern char *default_fstype(char *);
 					/* message */
 
 #define	NUMBER_WIDTH		40
+CTASSERT(NUMBER_WIDTH >= NN_NUMBUF_SZ);
 
 /*
  * A numbuf_t is used when converting a number to a string representation
@@ -219,7 +225,6 @@ static bool_int		o_option;
 
 static bool_int		tty_output;
 static bool_int		use_scaling;
-static int		scale;
 
 static void usage(void);
 static void do_devnm(int, char **);
@@ -591,7 +596,6 @@ parse_options(int argc, char *argv[])
 			SET_OPTION(g);
 		} else if (arg == 'h') {
 			use_scaling = TRUE;
-			scale = 1024;
 		} else if (arg == 'k' && ! k_option) {
 			SET_OPTION(k);
 		} else if (arg == 'l' && ! l_option) {
@@ -967,8 +971,7 @@ run_fs_specific_df(struct df_request request_list[], int entries)
  */
 static int
 prune_list(struct df_request request_list[],
-		size_t n_requests,
-		size_t *valid_requests)
+    size_t n_requests, size_t *valid_requests)
 {
 	size_t	i;
 	size_t	n_valid = 0;
@@ -1167,73 +1170,6 @@ number_to_string(
 }
 
 /*
- * Convert an unsigned long long to a string representation and place the
- * result in the caller-supplied buffer.
- * The given number is in units of "unit_from" size,
- * this will first be converted to a number in 1024 or 1000 byte size,
- * depending on the scaling factor.
- * Then the number is scaled down until it is small enough to be in a good
- * human readable format i.e. in the range 0 thru scale-1.
- * If it's smaller than 10 there's room enough to provide one decimal place.
- * The value "(unsigned long long)-1" is a special case and is always
- * converted to "-1".
- * Returns a pointer to the caller-supplied buffer.
- */
-static char *
-number_to_scaled_string(
-			numbuf_t buf,		/* put the result here */
-			unsigned long long number, /* convert this number */
-			int unit_from,
-			int scale)
-{
-	unsigned long long save = 0;
-	char *M = "KMGTPE"; /* Measurement: kilo, mega, giga, tera, peta, exa */
-	char *uom = M;    /* unit of measurement, initially 'K' (=M[0]) */
-
-	if ((long long)number == (long long)-1) {
-		(void) strcpy(buf, "-1");
-		return (buf);
-	}
-
-	/*
-	 * Convert number from unit_from to given scale (1024 or 1000).
-	 * This means multiply number by unit_from and divide by scale.
-	 *
-	 * Would like to multiply by unit_from and then divide by scale,
-	 * but if the first multiplication would overflow, then need to
-	 * divide by scale and then multiply by unit_from.
-	 */
-	if (number > (UINT64_MAX / (unsigned long long)unit_from)) {
-		number = (number / (unsigned long long)scale) *
-		    (unsigned long long)unit_from;
-	} else {
-		number = (number * (unsigned long long)unit_from) /
-		    (unsigned long long)scale;
-	}
-
-	/*
-	 * Now we have number as a count of scale units.
-	 * Stop scaling when we reached exa bytes, then something is
-	 * probably wrong with our number.
-	 */
-
-	while ((number >= scale) && (*uom != 'E')) {
-		uom++; /* next unit of measurement */
-		save = number;
-		number = (number + (scale / 2)) / scale;
-	}
-	/* check if we should output a decimal place after the point */
-	if (save && ((save / scale) < 10)) {
-		/* sprintf() will round for us */
-		float fnum = (float)save / scale;
-		(void) sprintf(buf, "%2.1f%c", fnum, *uom);
-	} else {
-		(void) sprintf(buf, "%4llu%c", number, *uom);
-	}
-	return (buf);
-}
-
-/*
  * The statvfs() implementation allows us to return only two values, the total
  * number of blocks and the number of blocks free.  The equation 'used = total -
  * free' will not work for ZFS filesystems, due to the nature of pooled storage.
@@ -1488,16 +1424,19 @@ k_output(struct df_request *dfrp, struct statvfs64 *fsp)
 	adjust_total_blocks(dfrp, &total_blocks, fsp->f_frsize);
 
 	if (use_scaling) { /* comes from the -h option */
-	(void) printf("%-*s %*s %*s %*s %-*s %-s\n",
-	    FILESYSTEM_WIDTH, file_system,
-	    SCALED_WIDTH, number_to_scaled_string(total_blocks_buf,
-	    total_blocks, fsp->f_frsize, scale),
-	    SCALED_WIDTH, number_to_scaled_string(used_blocks_buf,
-	    used_blocks, fsp->f_frsize, scale),
-	    AVAILABLE_WIDTH, number_to_scaled_string(available_blocks_buf,
-	    available_blocks, fsp->f_frsize, scale),
-	    CAPACITY_WIDTH, capacity_buf,
-	    DFR_MOUNT_POINT(dfrp));
+		nicenum_scale(total_blocks, fsp->f_frsize,
+		    total_blocks_buf, sizeof (total_blocks_buf), 0);
+		nicenum_scale(used_blocks, fsp->f_frsize,
+		    used_blocks_buf, sizeof (used_blocks_buf), 0);
+		nicenum_scale(available_blocks, fsp->f_frsize,
+		    available_blocks_buf, sizeof (available_blocks_buf), 0);
+
+		(void) printf("%-*s %*s %*s %*s %-*s %-s\n",
+		    FILESYSTEM_WIDTH, file_system,
+		    SCALED_WIDTH, total_blocks_buf,
+		    SCALED_WIDTH, used_blocks_buf,
+		    AVAILABLE_WIDTH, available_blocks_buf,
+		    CAPACITY_WIDTH, capacity_buf, DFR_MOUNT_POINT(dfrp));
 		return;
 	}
 
diff --git a/usr/src/cmd/ls/ls.c b/usr/src/cmd/ls/ls.c
index 1adab128a4..876ea20117 100644
--- a/usr/src/cmd/ls/ls.c
+++ b/usr/src/cmd/ls/ls.c
@@ -26,7 +26,7 @@
  */
 
 /*
- * Copyright 2009 Jason King.  All rights reserved.
+ * Copyright 2017 Jason King.  All rights reserved.
  * Use is subject to license terms.
  */
 
@@ -125,7 +125,6 @@
 
 #undef BUFSIZ
 #define	BUFSIZ 4096
-#define	NUMBER_WIDTH 40
 #define	FMTSIZE 50
 
 struct ditem {
@@ -216,11 +215,6 @@ struct dchain {
 	struct dchain *dc_next;	/* next directory in the chain */
 };
 
-/*
- * A numbuf_t is used when converting a number to a string representation
- */
-typedef char numbuf_t[NUMBER_WIDTH];
-
 static struct dchain *dfirst;	/* start of the dir chain */
 static struct dchain *cdfirst;	/* start of the current dir chain */
 static struct dchain *dtemp;	/* temporary - used for linking */
@@ -252,9 +246,6 @@ static struct cachenode *findincache(struct cachenode **, long);
 static void		csi_pprintf(unsigned char *);
 static void		pprintf(char *, char *);
 static int		compar(struct lbuf **pp1, struct lbuf **pp2);
-static char 		*number_to_scaled_string(numbuf_t buf,
-			    unsigned long long number,
-			    long scale);
 static void		record_ancestry(char *, struct stat *, struct lbuf *,
 			    int, struct ditem *);
 static void		ls_color_init(void);
@@ -306,7 +297,7 @@ static int		atm;
 static int		mtm;
 static int		crtm;
 static int		alltm;
-static long		hscale;
+static uint_t		nicenum_flags;
 static mode_t		flags;
 static int		err = 0;	/* Contains return code */
 static int		colorflg;
@@ -481,7 +472,7 @@ main(int argc, char *argv[])
 			if (strcmp(long_options[option_index].name,
 			    "si") == 0) {
 				hflg++;
-				hscale = 1000;
+				nicenum_flags |= NN_DIVISOR_1000;
 				continue;
 			}
 
@@ -751,7 +742,6 @@ main(int argc, char *argv[])
 			continue;
 		case 'h':
 			hflg++;
-			hscale = 1024;
 			continue;
 		case 'H':
 			Hflg++;
@@ -1255,7 +1245,6 @@ static void
 pentry(struct lbuf *ap)
 {
 	struct lbuf *p;
-	numbuf_t hbuf;
 	char *dmark = "";	/* Used if -p or -F option active */
 	char *cp;
 	char *str;
@@ -1308,9 +1297,13 @@ pentry(struct lbuf *ap)
 			curcol += printf("%3u, %2u",
 			    (uint_t)major((dev_t)p->lsize),
 			    (uint_t)minor((dev_t)p->lsize));
-		} else if (hflg && (p->lsize >= hscale)) {
-			curcol += printf("%7s",
-			    number_to_scaled_string(hbuf, p->lsize, hscale));
+		} else if (hflg) {
+			char numbuf[NN_NUMBUF_SZ];
+
+			nicenum_scale(p->lsize, 1, numbuf, sizeof (numbuf),
+			    nicenum_flags);
+
+			curcol += printf("%7s", numbuf);
 		} else {
 			uint64_t bsize = p->lsize / block_size;
 
@@ -2444,85 +2437,6 @@ strcol(unsigned char *s1)
 	return (w);
 }
 
-/*
- * Convert an unsigned long long to a string representation and place the
- * result in the caller-supplied buffer.
- *
- * The number provided is a size in bytes.  The number is first
- * converted to an integral multiple of 'scale' bytes.  This new
- * number is then scaled down until it is small enough to be in a good
- * human readable format, i.e.  in the range 0 thru scale-1.  If the
- * number used to derive the final number is not a multiple of scale, and
- * the final number has only a single significant digit, we compute
- * tenths of units to provide a second significant digit.
- *
- * The value "(unsigned long long)-1" is a special case and is always
- * converted to "-1".
- *
- * A pointer to the caller-supplied buffer is returned.
- */
-static char *
-number_to_scaled_string(
-			numbuf_t buf,		/* put the result here */
-			unsigned long long number, /* convert this number */
-			long scale)
-{
-	unsigned long long save;
-	/* Measurement: kilo, mega, giga, tera, peta, exa */
-	char *uom = "KMGTPE";
-
-	if ((long long)number == (long long)-1) {
-		(void) strlcpy(buf, "-1", sizeof (numbuf_t));
-		return (buf);
-	}
-
-	save = number;
-	number = number / scale;
-
-	/*
-	 * Now we have number as a count of scale units.
-	 * If no further scaling is necessary, we round up as appropriate.
-	 *
-	 * The largest value number could have had entering the routine is
-	 * 16 Exabytes, so running off the end of the uom array should
-	 * never happen.  We check for that, though, as a guard against
-	 * a breakdown elsewhere in the algorithm.
-	 */
-	if (number < (unsigned long long)scale) {
-		if ((save % scale) >= (unsigned long long)(scale / 2)) {
-			if (++number == (unsigned long long)scale) {
-				uom++;
-				number = 1;
-			}
-		}
-	} else {
-		while ((number >= (unsigned long long)scale) && (*uom != 'E')) {
-			uom++; /* next unit of measurement */
-			save = number;
-			/*
-			 * If we're over half way to the next unit of
-			 * 'scale' bytes (which means we should round
-			 * up), then adding half of 'scale' prior to
-			 * the division will push us into that next
-			 * unit of scale when we perform the division
-			 */
-			number = (number + (scale / 2)) / scale;
-		}
-	}
-
-	/* check if we should output a decimal place after the point */
-	if ((save / scale) < 10) {
-		/* snprintf() will round for us */
-		float fnum = (float)save / scale;
-		(void) snprintf(buf, sizeof (numbuf_t), "%2.1f%c",
-		    fnum, *uom);
-	} else {
-		(void) snprintf(buf, sizeof (numbuf_t), "%4llu%c",
-		    number, *uom);
-	}
-	return (buf);
-}
-
 /* Get extended system attributes and set the display */
 
 int
diff --git a/usr/src/cmd/stat/fsstat/Makefile b/usr/src/cmd/stat/fsstat/Makefile
index 26bfdb023b..b86e2cc8f7 100644
--- a/usr/src/cmd/stat/fsstat/Makefile
+++ b/usr/src/cmd/stat/fsstat/Makefile
@@ -33,7 +33,7 @@ include $(SRC)/cmd/stat/Makefile.stat
 COMMON_OBJS = common.o timestamp.o
 COMMON_SRCS = $(COMMON_OBJS:%.o=$(STATCOMMONDIR)/%.c)
 
-LDLIBS += -lkstat
+LDLIBS += -lkstat -lcmdutils
 CFLAGS += $(CCVERBOSE) -I${STATCOMMONDIR}
 CERRWARN += -_gcc=-Wno-parentheses
 FILEMODE= 0555
diff --git a/usr/src/cmd/stat/fsstat/fsstat.c b/usr/src/cmd/stat/fsstat/fsstat.c
index 5563f410ca..6bf07e333e 100644
--- a/usr/src/cmd/stat/fsstat/fsstat.c
+++ b/usr/src/cmd/stat/fsstat/fsstat.c
@@ -22,6 +22,7 @@
  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
  * Copyright (c) 2016 by Delphix. All rights reserved.
+ * Copyright 2017 Jason King
  */
 
 #include <stdio.h>
@@ -41,12 +42,14 @@
 #include <sys/fstyp.h>
 #include <sys/fsid.h>
 #include <sys/mnttab.h>
+#include <sys/debug.h>
 #include <values.h>
 #include <poll.h>
 #include <ctype.h>
 #include <libintl.h>
 #include <locale.h>
 #include <signal.h>
+#include <libcmdutils.h>
 
 #include "statcommon.h"
 
@@ -73,12 +76,7 @@
 #define	HEADERLINES	12	/* Number of lines between display headers */
 
 #define	LBUFSZ		64	/* Generic size for local buffer */
-
-/*
- * The following are used for the nicenum() function
- */
-#define	KILO_VAL	1024
-#define	ONE_INDEX	3
+CTASSERT(LBUFSZ >= NN_NUMBUF_SZ);
 
 #define	NENTITY_INIT	1	/* Initial number of entities to allocate */
 
@@ -112,9 +110,6 @@ typedef struct entity {
 #define	ENTYPE_FSTYPE	1
 #define	ENTYPE_MNTPT	2
 
-/* If more sub-one units are added, make sure to adjust ONE_INDEX above */
-static char units[] = "num KMGTPE";
-
 char		*cmdname;	/* name of this command */
 int		caught_cont = 0;	/* have caught a SIGCONT */
 
@@ -131,70 +126,14 @@ usage()
 	exit(2);
 }
 
-/*
- * Given a 64-bit number and a starting unit (e.g., n - nanoseconds),
- * convert the number to a 5-character representation including any
- * decimal point and single-character unit.  Put that representation
- * into the array "buf" (which had better be big enough).
- */
-char *
-nicenum(uint64_t num, char unit, char *buf)
-{
-	uint64_t n = num;
-	int unit_index;
-	int index;
-	char u;
-
-	/* If the user passed in a NUL/zero unit, use the blank value for 1 */
-	if (unit == '\0')
-		unit = ' ';
-
-	unit_index = 0;
-	while (units[unit_index] != unit) {
-		unit_index++;
-		if (unit_index > sizeof (units) - 1) {
-			(void) sprintf(buf, "??");
-			return (buf);
-		}
-	}
-
-	index = 0;
-	while (n >= KILO_VAL) {
-		n = (n + (KILO_VAL / 2)) / KILO_VAL; /* Round up or down */
-		index++;
-		unit_index++;
-	}
-
-	if (unit_index >= sizeof (units) - 1) {
-		(void) sprintf(buf, "??");
-		return (buf);
-	}
-
-	u = units[unit_index];
-
-	if (unit_index == ONE_INDEX) {
-		(void) sprintf(buf, "%llu", (u_longlong_t)n);
-	} else if (n < 10 && (num & (num - 1)) != 0) {
-		(void) sprintf(buf, "%.2f%c",
-		    (double)num / (1ULL << 10 * index), u);
-	} else if (n < 100 && (num & (num - 1)) != 0) {
-		(void) sprintf(buf, "%.1f%c",
-		    (double)num / (1ULL << 10 * index), u);
-	} else {
-		(void) sprintf(buf, "%llu%c", (u_longlong_t)n, u);
-	}
-
-	return (buf);
-}
-
-
 #define	RAWVAL(ptr, member) ((ptr)->member.value.ui64)
 #define	DELTA(member)	\
 	(newvsp->member.value.ui64 - (oldvsp ? oldvsp->member.value.ui64 : 0))
 
-#define	PRINTSTAT(isnice, nicestring, rawstring, rawval, unit, buf)	\
+#define	PRINTSTAT(isnice, nicestring, rawstring, rawval, buf)		\
 	(isnice) ?	 						\
-		(void) printf((nicestring), nicenum(rawval, unit, buf))	\
+		nicenum(rawval, buf, sizeof (buf)),			\
+		(void) printf((nicestring), (buf))			\
 	:								\
 		(void) printf((rawstring), (rawval))
 
@@ -256,17 +195,17 @@ dflt_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 " file remov  chng   get   set    ops   ops   ops bytes   ops bytes\n");
 	}
 
-	PRINTSTAT(niceflag, "%5s ", "%lld:", nnewfile, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", nnamerm, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", nnamechg, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", nattrret, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", nattrchg, ' ', buf);
-	PRINTSTAT(niceflag, " %5s ", "%lld:", nlookup, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", nreaddir, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", ndataread, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", readthruput, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", ndatawrite, ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", writethruput, ' ', buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", nnewfile, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", nnamerm, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", nnamechg, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", nattrret, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", nattrchg, buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", nlookup, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", nreaddir, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", ndataread, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", readthruput, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", ndatawrite, buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", writethruput, buf);
 	(void) printf("%s\n", name);
 }
 
@@ -282,17 +221,17 @@ io_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 "  ops bytes   ops bytes   ops bytes    ops     ops\n");
 	}
 
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nread), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(read_bytes), ' ', buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nread), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(read_bytes), buf);
 
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nwrite), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(write_bytes), ' ', buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nwrite), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(write_bytes), buf);
 
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nreaddir), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(readdir_bytes), ' ', buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nreaddir), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(readdir_bytes), buf);
 
-	PRINTSTAT(niceflag, " %5s   ", "%lld:", DELTA(nrwlock), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nrwunlock), ' ', buf);
+	PRINTSTAT(niceflag, " %5s   ", "%lld:", DELTA(nrwlock), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nrwunlock), buf);
 
 	(void) printf("%s\n", name);
 }
@@ -307,12 +246,12 @@ vm_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 		(void) printf("  map addmap delmap getpag putpag pagio\n");
 	}
 
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nmap), ' ', buf);
-	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(naddmap), ' ', buf);
-	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(ndelmap), ' ', buf);
-	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(ngetpage), ' ', buf);
-	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(nputpage), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(npageio), ' ', buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nmap), buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(naddmap), buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(ndelmap), buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(ngetpage), buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(nputpage), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(npageio), buf);
 	(void) printf("%s\n", name);
 }
 
@@ -326,10 +265,10 @@ attr_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 		(void) printf("getattr setattr getsec  setsec\n");
 	}
 
-	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(ngetattr), ' ', buf);
-	PRINTSTAT(niceflag, "  %5s ", "%lld:", DELTA(nsetattr), ' ', buf);
-	PRINTSTAT(niceflag, "  %5s ", "%lld:", DELTA(ngetsecattr), ' ', buf);
-	PRINTSTAT(niceflag, "  %5s ", "%lld:", DELTA(nsetsecattr), ' ', buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(ngetattr), buf);
+	PRINTSTAT(niceflag, "  %5s ", "%lld:", DELTA(nsetattr), buf);
+	PRINTSTAT(niceflag, "  %5s ", "%lld:", DELTA(ngetsecattr), buf);
+	PRINTSTAT(niceflag, "  %5s ", "%lld:", DELTA(nsetsecattr), buf);
 
 	(void) printf("%s\n", name);
 }
@@ -345,16 +284,16 @@ naming_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 	"lookup creat remov  link renam mkdir rmdir rddir symlnk rdlnk\n");
 	}
 
-	PRINTSTAT(niceflag, "%5s  ", "%lld:", DELTA(nlookup), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(ncreate), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nremove), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nlink), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nrename), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nmkdir), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nrmdir), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nreaddir), ' ', buf);
-	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(nsymlink), ' ', buf);
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nreadlink), ' ', buf);
+	PRINTSTAT(niceflag, "%5s  ", "%lld:", DELTA(nlookup), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(ncreate), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nremove), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nlink), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nrename), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nmkdir), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nrmdir), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nreaddir), buf);
+	PRINTSTAT(niceflag, " %5s ", "%lld:", DELTA(nsymlink), buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(nreadlink), buf);
 	(void) printf("%s\n", name);
 }
 
@@ -362,7 +301,7 @@ naming_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 #define	PRINT_VOPSTAT_CMN(niceflag, vop)				\
 	if (niceflag)							\
 		(void) printf("%10s ", #vop);				\
-	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(n##vop), ' ', buf);
+	PRINTSTAT(niceflag, "%5s ", "%lld:", DELTA(n##vop), buf);
 
 #define	PRINT_VOPSTAT(niceflag, vop) 					\
 	PRINT_VOPSTAT_CMN(niceflag, vop);				\
@@ -372,7 +311,7 @@ naming_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
 #define	PRINT_VOPSTAT_IO(niceflag, vop)					\
 	PRINT_VOPSTAT_CMN(niceflag, vop);				\
 	PRINTSTAT(niceflag, " %5s\n", "%lld:",				\
-		DELTA(vop##_bytes), ' ', buf);
+		DELTA(vop##_bytes), buf);
 
 static void
 vop_display(char *name, vopstats_t *oldvsp, vopstats_t *newvsp, int dispflag)
diff --git a/usr/src/cmd/swap/Makefile.com b/usr/src/cmd/swap/Makefile.com
index 3734d8ac58..0514c15e62 100644
--- a/usr/src/cmd/swap/Makefile.com
+++ b/usr/src/cmd/swap/Makefile.com
@@ -43,7 +43,7 @@ CLEANFILES += $(OBJS)
 
 all: $(PROG)
 
-LDLIBS	+=	-ldiskmgt
+LDLIBS	+=	-ldiskmgt -lcmdutils
 $(PROG): $(OBJS)
 	$(LINK.c) $(OBJS) -o $@ $(LDLIBS)
 	$(POST_PROCESS)
diff --git a/usr/src/cmd/swap/swap.c b/usr/src/cmd/swap/swap.c
index 91cecd5cb4..6b4522745d 100644
--- a/usr/src/cmd/swap/swap.c
+++ b/usr/src/cmd/swap/swap.c
@@ -36,7 +36,9 @@
  * contributors.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
+/*
+ * Copyright 2017 Jason King.
+ */
 
 /*
  * 	Swap administrative interface
@@ -64,6 +66,8 @@
 #include	<libintl.h>
 #include	<libdiskmgt.h>
 #include	<sys/fs/zfs.h>
+#include	<libcmdutils.h>
+#include	<sys/debug.h>
 
 #define	LFLAG	0x01	/* swap -l (list swap devices) */
 #define	DFLAG	0x02	/* swap -d (delete swap device) */
@@ -75,6 +79,8 @@
 #define	KFLAG	0x80	/* swap -k (size in kilobytes) */
 
 #define	NUMBER_WIDTH	64
+/* make sure nicenum_scale() has enough space */
+CTASSERT(NUMBER_WIDTH >= NN_NUMBUF_SZ);
 typedef char numbuf_t[NUMBER_WIDTH];
 
 static char *prognamep;
@@ -85,9 +91,6 @@ static void usage(void);
 static int doswap(int flag);
 static int valid(char *, off_t, off_t);
 static int list(int flag);
-static char *number_to_scaled_string(numbuf_t buf, unsigned long long number,
-		unsigned long long unit_from, unsigned long long scale);
-
 
 int
 main(int argc, char **argv)
@@ -253,7 +256,7 @@ main(int argc, char **argv)
 		}
 		if ((ret = valid(pathname,
 		    s_offset * 512, length * 512)) == 0) {
-		    ret = add(pathname, s_offset, length, flag);
+			ret = add(pathname, s_offset, length, flag);
 		}
 	}
 	if (!(flag & ~HFLAG & ~KFLAG)) {
@@ -271,16 +274,16 @@ usage(void)
 	(void) fprintf(stderr, gettext("Usage:\t%s -l\n"), prognamep);
 	(void) fprintf(stderr, gettext("\tsub option :\n"));
 	(void) fprintf(stderr, gettext("\t\t-h : displays size in human "
-				"readable format\n"));
+	    "readable format\n"));
 	(void) fprintf(stderr, gettext("\t\t-k : displays size in KB\n"));
 	(void) fprintf(stderr, "\t%s -s\n", prognamep);
 	(void) fprintf(stderr, gettext("\tsub option :\n"));
 	(void) fprintf(stderr, gettext("\t\t-h : displays size in human "
-				"readable format rather than KB\n"));
+	    "readable format rather than KB\n"));
 	(void) fprintf(stderr, gettext("\t%s -d <file name> [low block]\n"),
-				prognamep);
+	    prognamep);
 	(void) fprintf(stderr, gettext("\t%s -a <file name> [low block]"
-				" [nbr of blocks]\n"), prognamep);
+	    " [nbr of blocks]\n"), prognamep);
 }
 
 /*
@@ -305,7 +308,6 @@ doswap(int flag)
 	struct anoninfo ai;
 	pgcnt_t allocated, reserved, available;
 	numbuf_t numbuf;
-	unsigned long long scale = 1024L;
 
 	/*
 	 * max = total amount of swap space including physical memory
@@ -339,24 +341,25 @@ doswap(int flag)
 
 	if (flag & HFLAG) {
 		int factor = (int)(sysconf(_SC_PAGESIZE));
-		(void) printf(gettext("total: %s allocated + "),
-				number_to_scaled_string(numbuf, allocated,
-				factor, scale));
-		(void) printf(gettext("%s reserved = "),
-				number_to_scaled_string(numbuf, reserved,
-				factor, scale));
-		(void) printf(gettext("%s used, "),
-				number_to_scaled_string(numbuf,
-				allocated + reserved, factor, scale));
-		(void) printf(gettext("%s available\n"),
-				number_to_scaled_string(numbuf, available,
-				factor, scale));
+
+		nicenum_scale(allocated, factor, numbuf, sizeof (numbuf), 0);
+		(void) printf(gettext("total: %s allocated + "), numbuf);
+
+		nicenum_scale(reserved, factor, numbuf, sizeof (numbuf), 0);
+		(void) printf(gettext("%s reserved = "), numbuf);
+
+		nicenum_scale(allocated + reserved, factor, numbuf,
+		    sizeof (numbuf), 0);
+		(void) printf(gettext("%s used, "), numbuf);
+
+		nicenum_scale(available, factor, numbuf, sizeof (numbuf), 0);
+		(void) printf(gettext("%s available\n"), numbuf);
 	} else {
 		(void) printf(gettext("total: %luk bytes allocated + %luk"
-				" reserved = %luk used, %luk available\n"),
-				ctok(allocated), ctok(reserved),
-				ctok(reserved) + ctok(allocated),
-				ctok(available));
+		    " reserved = %luk used, %luk available\n"),
+		    ctok(allocated), ctok(reserved),
+		    ctok(reserved) + ctok(allocated),
+		    ctok(available));
 	}
 
 	return (0);
@@ -373,7 +376,6 @@ list(int flag)
 	char		fullpath[MAXPATHLEN+1];
 	int		num;
 	numbuf_t numbuf;
-	unsigned long long scale = 1024L;
 
 	if ((num = swapctl(SC_GETNSWP, NULL)) == -1) {
 		perror(prognamep);
@@ -387,13 +389,13 @@ list(int flag)
 	if ((st = malloc(num * sizeof (swapent_t) + sizeof (int)))
 	    == NULL) {
 		(void) fprintf(stderr,
-			gettext("Malloc failed. Please try later.\n"));
+		    gettext("Malloc failed. Please try later.\n"));
 		perror(prognamep);
 		return (2);
 	}
 	if ((path = malloc(num * MAXPATHLEN)) == NULL) {
 		(void) fprintf(stderr,
-			gettext("Malloc failed. Please try later.\n"));
+		    gettext("Malloc failed. Please try later.\n"));
 		perror(prognamep);
 		return (2);
 	}
@@ -431,17 +433,17 @@ list(int flag)
 	for (i = 0; i < num; i++, swapent++) {
 		if (*swapent->ste_path != '/')
 			(void) snprintf(fullpath, sizeof (fullpath),
-				"/dev/%s", swapent->ste_path);
+			    "/dev/%s", swapent->ste_path);
 		else
 			(void) snprintf(fullpath, sizeof (fullpath),
-				"%s", swapent->ste_path);
+			    "%s", swapent->ste_path);
 		if (stat64(fullpath, &statbuf) < 0)
 			if (*swapent->ste_path != '/')
 				(void) printf(gettext("%-20s  -  "),
-					swapent->ste_path);
+				    swapent->ste_path);
 			else
 				(void) printf(gettext("%-20s ?,? "),
-					fullpath);
+				    fullpath);
 		else {
 			if (S_ISBLK(statbuf.st_mode) ||
 			    S_ISCHR(statbuf.st_mode)) {
@@ -455,34 +457,31 @@ list(int flag)
 		}
 		{
 		int diskblks_per_page =
-			(int)(sysconf(_SC_PAGESIZE) >> DEV_BSHIFT);
+		    (int)(sysconf(_SC_PAGESIZE) >> DEV_BSHIFT);
 		if (flag & HFLAG) {
-			(void) printf(gettext(" %8s"),
-					number_to_scaled_string(numbuf,
-					swapent->ste_start, DEV_BSIZE,
-					scale));
-			(void) printf(gettext(" %8s"),
-					number_to_scaled_string(numbuf,
-					swapent->ste_pages *
-						diskblks_per_page,
-					DEV_BSIZE, scale));
-			(void) printf(gettext(" %8s"),
-					number_to_scaled_string(numbuf,
-					swapent->ste_free *
-						diskblks_per_page,
-					DEV_BSIZE, scale));
+			nicenum_scale(swapent->ste_start, DEV_BSIZE, numbuf,
+			    sizeof (numbuf), 0);
+			(void) printf(gettext(" %8s"), numbuf);
+
+			nicenum_scale(swapent->ste_pages, DEV_BSIZE *
+			    diskblks_per_page, numbuf, sizeof (numbuf), 0);
+			(void) printf(gettext(" %8s"), numbuf);
+
+			nicenum_scale(swapent->ste_free, DEV_BSIZE *
+			    diskblks_per_page, numbuf, sizeof (numbuf), 0);
+			(void) printf(gettext(" %8s"), numbuf);
 		} else if (flag & KFLAG) {
 			(void) printf(gettext(" %7luK %7luK %7luK"),
-					swapent->ste_start * DEV_BSIZE / 1024,
-					swapent->ste_pages * diskblks_per_page *
-						DEV_BSIZE / 1024,
-					swapent->ste_free * diskblks_per_page *
-						DEV_BSIZE / 1024);
+			    swapent->ste_start * DEV_BSIZE / 1024,
+			    swapent->ste_pages * diskblks_per_page *
+			    DEV_BSIZE / 1024,
+			    swapent->ste_free * diskblks_per_page *
+			    DEV_BSIZE / 1024);
 		} else {
 			(void) printf(gettext(" %8lu %8lu %8lu"),
-					swapent->ste_start,
-					swapent->ste_pages * diskblks_per_page,
-					swapent->ste_free * diskblks_per_page);
+			    swapent->ste_start,
+			    swapent->ste_pages * diskblks_per_page,
+			    swapent->ste_free * diskblks_per_page);
 		}
 		}
 		if (swapent->ste_flags & ST_INDEL)
@@ -493,64 +492,6 @@ list(int flag)
 	return (0);
 }
 
-/* Copied from du.c */
-static char *
-number_to_scaled_string(
-	numbuf_t buf,			/* put the result here */
-	unsigned long long number,	/* convert this number */
-	unsigned long long unit_from,	/* number of byes per input unit */
-	unsigned long long scale)	/* 1024 (-h) or 1000 (-H) */
-{
-	unsigned long long save = 0;
-	char *M = "KMGTPE"; /* Measurement: kilo, mega, giga, tera, peta, exa */
-	char *uom = M;	/* unit of measurement, initially 'K' (=M[0]) */
-
-	if ((long long)number == (long long) -1) {
-		(void) strcpy(buf, "-1");
-		return (buf);
-	}
-
-	/*
-	 * Convert number from unit_from to given scale (1024 or 1000)
-	 * This means multiply number with unit_from and divide by scale.
-	 * if number is large enough, we first divide and then multiply
-	 * to avoid an overflow (large enough here means 100 (rather arbitrary
-	 * value) times scale in order to reduce rounding errors)
-	 * otherwise, we first multiply and then divide to avoid an underflow.
-	 */
-	if (number >= 100L * scale) {
-		number = number / scale;
-		number = number * unit_from;
-	} else {
-		number = number * unit_from;
-		number = number / scale;
-	}
-
-	/*
-	 * Now we have number as a count of scale units.
-	 * Stop scaling when we reached exa bytes, then something is
-	 * probably wrong with our number.
-	 */
-	while ((number >= scale) && (*uom != 'E')) {
-		uom++;	/* Next unit of measurement */
-		save = number;
-		number = (number + (scale / 2)) / scale;
-	}
-
-	/* Check if we should output a decimal place after the point */
-	if (save && ((save / scale) < 10)) {
-		/* sprintf() will round for us */
-		float fnum = (float)save / scale;
-		(void) sprintf(buf, "%.1f%c", fnum, *uom);
-	} else {
-		(void) sprintf(buf, "%llu%c", number, *uom);
-	}
-	return (buf);
-}
-
-
-
-
 static void
 dumpadm_err(const char *warning)
 {
@@ -701,7 +642,7 @@ add(char *path, off_t offset, off_t cnt, int flags)
 	    statvfs("/etc", &fsb) == 0 && !(fsb.f_flag & ST_RDONLY)) {
 
 		(void) printf(
-			gettext("operating system crash dump was previously "
+		    gettext("operating system crash dump was previously "
 		    "disabled --\ninvoking dumpadm(1M) -d swap to select "
 		    "new dump device\n"));
 
@@ -726,7 +667,7 @@ valid(char *pathname, off_t offset, off_t length)
 	}
 
 	if (!((S_ISREG(f.st_mode) && (f.st_mode & S_ISVTX) == S_ISVTX) ||
-		S_ISBLK(f.st_mode))) {
+	    S_ISBLK(f.st_mode))) {
 		(void) fprintf(stderr,
 		    gettext("\"%s\" is not valid for swapping.\n"
 		    "It must be a block device or a regular file with the\n"
@@ -753,8 +694,8 @@ valid(char *pathname, off_t offset, off_t length)
 
 		if (offset < 0) {
 			(void) fprintf(stderr,
-				gettext("%s: low block is invalid\n"),
-				pathname);
+			    gettext("%s: low block is invalid\n"),
+			    pathname);
 			return (EINVAL);
 		}
 
diff --git a/usr/src/cmd/zdb/Makefile.com b/usr/src/cmd/zdb/Makefile.com
index 63b8366c80..022c984dbe 100644
--- a/usr/src/cmd/zdb/Makefile.com
+++ b/usr/src/cmd/zdb/Makefile.com
@@ -23,6 +23,7 @@
 # Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 # Use is subject to license terms.
 # Copyright (c) 2012 by Delphix. All rights reserved.
+# Copyright 2017 Joyent, Inc.
 #
 
 PROG:sh=	cd ..; basename `pwd`
@@ -36,7 +37,7 @@ INCS += -I../../../lib/libzpool/common
 INCS +=	-I../../../uts/common/fs/zfs
 INCS +=	-I../../../common/zfs
 
-LDLIBS += -lzpool -lumem -lnvpair -lzfs -lavl
+LDLIBS += -lzpool -lumem -lnvpair -lzfs -lavl -lcmdutils
 
 C99MODE=	-xc99=%all
 C99LMODE=	-Xc99=%all
diff --git a/usr/src/cmd/zdb/zdb.c b/usr/src/cmd/zdb/zdb.c
index a2e0a67e11..5dcb12f5bf 100644
--- a/usr/src/cmd/zdb/zdb.c
+++ b/usr/src/cmd/zdb/zdb.c
@@ -63,6 +63,7 @@
 #include <sys/abd.h>
 #include <sys/blkptr.h>
 #include <zfs_comutil.h>
+#include <libcmdutils.h>
 #undef verify
 #include <libzfs.h>
 
@@ -276,12 +277,12 @@ dump_history_offsets(objset_t *os, uint64_t object, void *data, size_t size)
 }
 
 static void
-zdb_nicenum(uint64_t num, char *buf)
+zdb_nicenum(uint64_t num, char *buf, size_t buflen)
 {
 	if (dump_opt['P'])
-		(void) sprintf(buf, "%llu", (longlong_t)num);
+		(void) snprintf(buf, buflen, "%llu", (longlong_t)num);
 	else
-		nicenum(num, buf);
+		nicenum(num, buf, sizeof (buf));
 }
 
 const char histo_stars[] = "****************************************";
@@ -458,12 +459,17 @@ dump_bpobj(objset_t *os, uint64_t object, void *data, size_t size)
 	bpobj_phys_t *bpop = data;
 	char bytes[32], comp[32], uncomp[32];
 
+	/* make sure the output won't get truncated */
+	CTASSERT(sizeof (bytes) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (comp) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (uncomp) >= NN_NUMBUF_SZ);
+
 	if (bpop == NULL)
 		return;
 
-	zdb_nicenum(bpop->bpo_bytes, bytes);
-	zdb_nicenum(bpop->bpo_comp, comp);
-	zdb_nicenum(bpop->bpo_uncomp, uncomp);
+	zdb_nicenum(bpop->bpo_bytes, bytes, sizeof (bytes));
+	zdb_nicenum(bpop->bpo_comp, comp, sizeof (comp));
+	zdb_nicenum(bpop->bpo_uncomp, uncomp, sizeof (uncomp));
 
 	(void) printf("\t\tnum_blkptrs = %llu\n",
 	    (u_longlong_t)bpop->bpo_num_blkptrs);
@@ -756,7 +762,10 @@ dump_metaslab_stats(metaslab_t *msp)
 	avl_tree_t *t = &msp->ms_size_tree;
 	int free_pct = range_tree_space(rt) * 100 / msp->ms_size;
 
-	zdb_nicenum(metaslab_block_maxsize(msp), maxbuf);
+	/* max sure nicenum has enough space */
+	CTASSERT(sizeof (maxbuf) >= NN_NUMBUF_SZ);
+
+	zdb_nicenum(metaslab_block_maxsize(msp), maxbuf, sizeof (maxbuf));
 
 	(void) printf("\t %25s %10lu   %7s  %6s   %4s %4d%%\n",
 	    "segments", avl_numnodes(t), "maxsize", maxbuf,
@@ -773,7 +782,8 @@ dump_metaslab(metaslab_t *msp)
 	space_map_t *sm = msp->ms_sm;
 	char freebuf[32];
 
-	zdb_nicenum(msp->ms_size - space_map_allocated(sm), freebuf);
+	zdb_nicenum(msp->ms_size - space_map_allocated(sm), freebuf,
+	    sizeof (freebuf));
 
 	(void) printf(
 	    "\tmetaslab %6llu   offset %12llx   spacemap %6llu   free    %5s\n",
@@ -1331,6 +1341,9 @@ dump_dsl_dir(objset_t *os, uint64_t object, void *data, size_t size)
 	time_t crtime;
 	char nice[32];
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (nice) >= NN_NUMBUF_SZ);
+
 	if (dd == NULL)
 		return;
 
@@ -1346,15 +1359,15 @@ dump_dsl_dir(objset_t *os, uint64_t object, void *data, size_t size)
 	    (u_longlong_t)dd->dd_origin_obj);
 	(void) printf("\t\tchild_dir_zapobj = %llu\n",
 	    (u_longlong_t)dd->dd_child_dir_zapobj);
-	zdb_nicenum(dd->dd_used_bytes, nice);
+	zdb_nicenum(dd->dd_used_bytes, nice, sizeof (nice));
 	(void) printf("\t\tused_bytes = %s\n", nice);
-	zdb_nicenum(dd->dd_compressed_bytes, nice);
+	zdb_nicenum(dd->dd_compressed_bytes, nice, sizeof (nice));
 	(void) printf("\t\tcompressed_bytes = %s\n", nice);
-	zdb_nicenum(dd->dd_uncompressed_bytes, nice);
+	zdb_nicenum(dd->dd_uncompressed_bytes, nice, sizeof (nice));
 	(void) printf("\t\tuncompressed_bytes = %s\n", nice);
-	zdb_nicenum(dd->dd_quota, nice);
+	zdb_nicenum(dd->dd_quota, nice, sizeof (nice));
 	(void) printf("\t\tquota = %s\n", nice);
-	zdb_nicenum(dd->dd_reserved, nice);
+	zdb_nicenum(dd->dd_reserved, nice, sizeof (nice));
 	(void) printf("\t\treserved = %s\n", nice);
 	(void) printf("\t\tprops_zapobj = %llu\n",
 	    (u_longlong_t)dd->dd_props_zapobj);
@@ -1364,7 +1377,8 @@ dump_dsl_dir(objset_t *os, uint64_t object, void *data, size_t size)
 	    (u_longlong_t)dd->dd_flags);
 
 #define	DO(which) \
-	zdb_nicenum(dd->dd_used_breakdown[DD_USED_ ## which], nice); \
+	zdb_nicenum(dd->dd_used_breakdown[DD_USED_ ## which], nice, \
+	    sizeof (nice)); \
 	(void) printf("\t\tused_breakdown[" #which "] = %s\n", nice)
 	DO(HEAD);
 	DO(SNAP);
@@ -1383,15 +1397,22 @@ dump_dsl_dataset(objset_t *os, uint64_t object, void *data, size_t size)
 	char used[32], compressed[32], uncompressed[32], unique[32];
 	char blkbuf[BP_SPRINTF_LEN];
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (used) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (compressed) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (uncompressed) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (unique) >= NN_NUMBUF_SZ);
+
 	if (ds == NULL)
 		return;
 
 	ASSERT(size == sizeof (*ds));
 	crtime = ds->ds_creation_time;
-	zdb_nicenum(ds->ds_referenced_bytes, used);
-	zdb_nicenum(ds->ds_compressed_bytes, compressed);
-	zdb_nicenum(ds->ds_uncompressed_bytes, uncompressed);
-	zdb_nicenum(ds->ds_unique_bytes, unique);
+	zdb_nicenum(ds->ds_referenced_bytes, used, sizeof (used));
+	zdb_nicenum(ds->ds_compressed_bytes, compressed, sizeof (compressed));
+	zdb_nicenum(ds->ds_uncompressed_bytes, uncompressed,
+	    sizeof (uncompressed));
+	zdb_nicenum(ds->ds_unique_bytes, unique, sizeof (unique));
 	snprintf_blkptr(blkbuf, sizeof (blkbuf), &ds->ds_bp);
 
 	(void) printf("\t\tdir_obj = %llu\n",
@@ -1450,12 +1471,15 @@ dump_bptree(objset_t *os, uint64_t obj, char *name)
 	bptree_phys_t *bt;
 	dmu_buf_t *db;
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (bytes) >= NN_NUMBUF_SZ);
+
 	if (dump_opt['d'] < 3)
 		return;
 
 	VERIFY3U(0, ==, dmu_bonus_hold(os, obj, FTAG, &db));
 	bt = db->db_data;
-	zdb_nicenum(bt->bt_bytes, bytes);
+	zdb_nicenum(bt->bt_bytes, bytes, sizeof (bytes));
 	(void) printf("\n    %s: %llu datasets, %s\n",
 	    name, (unsigned long long)(bt->bt_end - bt->bt_begin), bytes);
 	dmu_buf_rele(db, FTAG);
@@ -1487,13 +1511,18 @@ dump_full_bpobj(bpobj_t *bpo, char *name, int indent)
 	char comp[32];
 	char uncomp[32];
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (bytes) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (comp) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (uncomp) >= NN_NUMBUF_SZ);
+
 	if (dump_opt['d'] < 3)
 		return;
 
-	zdb_nicenum(bpo->bpo_phys->bpo_bytes, bytes);
+	zdb_nicenum(bpo->bpo_phys->bpo_bytes, bytes, sizeof (bytes));
 	if (bpo->bpo_havesubobj && bpo->bpo_phys->bpo_subobjs != 0) {
-		zdb_nicenum(bpo->bpo_phys->bpo_comp, comp);
-		zdb_nicenum(bpo->bpo_phys->bpo_uncomp, uncomp);
+		zdb_nicenum(bpo->bpo_phys->bpo_comp, comp, sizeof (comp));
+		zdb_nicenum(bpo->bpo_phys->bpo_uncomp, uncomp, sizeof (uncomp));
 		(void) printf("    %*s: object %llu, %llu local blkptrs, "
 		    "%llu subobjs in object %llu, %s (%s/%s comp)\n",
 		    indent * 8, name,
@@ -1547,6 +1576,11 @@ dump_deadlist(dsl_deadlist_t *dl)
 	char comp[32];
 	char uncomp[32];
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (bytes) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (comp) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (uncomp) >= NN_NUMBUF_SZ);
+
 	if (dump_opt['d'] < 3)
 		return;
 
@@ -1555,9 +1589,9 @@ dump_deadlist(dsl_deadlist_t *dl)
 		return;
 	}
 
-	zdb_nicenum(dl->dl_phys->dl_used, bytes);
-	zdb_nicenum(dl->dl_phys->dl_comp, comp);
-	zdb_nicenum(dl->dl_phys->dl_uncomp, uncomp);
+	zdb_nicenum(dl->dl_phys->dl_used, bytes, sizeof (bytes));
+	zdb_nicenum(dl->dl_phys->dl_comp, comp, sizeof (comp));
+	zdb_nicenum(dl->dl_phys->dl_uncomp, uncomp, sizeof (uncomp));
 	(void) printf("\n    Deadlist: %s (%s/%s comp)\n",
 	    bytes, comp, uncomp);
 
@@ -1860,6 +1894,13 @@ dump_object(objset_t *os, uint64_t object, int verbosity, int *print_header)
 	char aux[50];
 	int error;
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (iblk) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (dblk) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (lsize) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (asize) >= NN_NUMBUF_SZ);
+	CTASSERT(sizeof (bonus_size) >= NN_NUMBUF_SZ);
+
 	if (*print_header) {
 		(void) printf("\n%10s  %3s  %5s  %5s  %5s  %5s  %6s  %s\n",
 		    "Object", "lvl", "iblk", "dblk", "dsize", "lsize",
@@ -1880,11 +1921,11 @@ dump_object(objset_t *os, uint64_t object, int verbosity, int *print_header)
 	}
 	dmu_object_info_from_dnode(dn, &doi);
 
-	zdb_nicenum(doi.doi_metadata_block_size, iblk);
-	zdb_nicenum(doi.doi_data_block_size, dblk);
-	zdb_nicenum(doi.doi_max_offset, lsize);
-	zdb_nicenum(doi.doi_physical_blocks_512 << 9, asize);
-	zdb_nicenum(doi.doi_bonus_size, bonus_size);
+	zdb_nicenum(doi.doi_metadata_block_size, iblk, sizeof (iblk));
+	zdb_nicenum(doi.doi_data_block_size, dblk, sizeof (dblk));
+	zdb_nicenum(doi.doi_max_offset, lsize, sizeof (lsize));
+	zdb_nicenum(doi.doi_physical_blocks_512 << 9, asize, sizeof (asize));
+	zdb_nicenum(doi.doi_bonus_size, bonus_size, sizeof (bonus_size));
 	(void) sprintf(fill, "%6.2f", 100.0 * doi.doi_fill_count *
 	    doi.doi_data_block_size / (object == 0 ? DNODES_PER_BLOCK : 1) /
 	    doi.doi_max_offset);
@@ -1947,6 +1988,8 @@ dump_object(objset_t *os, uint64_t object, int verbosity, int *print_header)
 
 		for (;;) {
 			char segsize[32];
+			/* make sure nicenum has enough space */
+			CTASSERT(sizeof (segsize) >= NN_NUMBUF_SZ);
 			error = dnode_next_offset(dn,
 			    0, &start, minlvl, blkfill, 0);
 			if (error)
@@ -1954,7 +1997,7 @@ dump_object(objset_t *os, uint64_t object, int verbosity, int *print_header)
 			end = start;
 			error = dnode_next_offset(dn,
 			    DNODE_FIND_HOLE, &end, minlvl, blkfill, 0);
-			zdb_nicenum(end - start, segsize);
+			zdb_nicenum(end - start, segsize, sizeof (segsize));
 			(void) printf("\t\tsegment [%016llx, %016llx)"
 			    " size %5s\n", (u_longlong_t)start,
 			    (u_longlong_t)end, segsize);
@@ -1985,6 +2028,9 @@ dump_dir(objset_t *os)
 	int print_header = 1;
 	int i, error;
 
+	/* make sure nicenum has enough space */
+	CTASSERT(sizeof (numbuf) >= NN_NUMBUF_SZ);
+
 	dsl_pool_config_enter(dmu_objset_pool(os), FTAG);
 	dmu_objset_fast_stat(os, &dds);
 	dsl_pool_config_exit(dmu_objset_pool(os), FTAG);
@@ -2003,7 +2049,7 @@ dump_dir(objset_t *os)
 
 	ASSERT3U(usedobjs, ==, BP_GET_FILL(os->os_rootbp));
 
-	zdb_nicenum(refdbytes, numbuf);
+	zdb_nicenum(refdbytes, numbuf, sizeof (numbuf));
 
 	if (verbosity >= 4) {
 		(void) snprintf(blkbuf, sizeof (blkbuf), ", rootbp ");
@@ -2648,6 +2694,9 @@ zdb_blkptr_cb(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 		int sec_remaining =
 		    (zcb->zcb_totalasize - bytes) / 1024 / kb_per_sec;
 
+		/* make sure nicenum has enough space */
+		CTASSERT(sizeof (buf) >= NN_NUMBUF_SZ);
+
 		zfs_nicenum(bytes, buf, sizeof (buf));
 		(void) fprintf(stderr,
 		    "\r%5s completed (%4dMB/s) "
@@ -2997,6 +3046,14 @@ dump_block_stats(spa_t *spa)
 			char avg[32], gang[32];
 			char *typename;
 
+			/* make sure nicenum has enough space */
+			CTASSERT(sizeof (csize) >= NN_NUMBUF_SZ);
+			CTASSERT(sizeof (lsize) >= NN_NUMBUF_SZ);
+			CTASSERT(sizeof (psize) >= NN_NUMBUF_SZ);
+			CTASSERT(sizeof (asize) >= NN_NUMBUF_SZ);
+			CTASSERT(sizeof (avg) >= NN_NUMBUF_SZ);
+			CTASSERT(sizeof (gang) >= NN_NUMBUF_SZ);
+
 			if (t < DMU_OT_NUMTYPES)
 				typename = dmu_ot[t].ot_name;
 			else
@@ -3030,12 +3087,17 @@ dump_block_stats(spa_t *spa)
 				    zcb.zcb_type[ZB_TOTAL][t].zb_asize)
 					continue;
 
-				zdb_nicenum(zb->zb_count, csize);
-				zdb_nicenum(zb->zb_lsize, lsize);
-				zdb_nicenum(zb->zb_psize, psize);
-				zdb_nicenum(zb->zb_asize, asize);
-				zdb_nicenum(zb->zb_asize / zb->zb_count, avg);
-				zdb_nicenum(zb->zb_gangs, gang);
+				zdb_nicenum(zb->zb_count, csize,
+				    sizeof (csize));
+				zdb_nicenum(zb->zb_lsize, lsize,
+				    sizeof (lsize));
+				zdb_nicenum(zb->zb_psize, psize,
+				    sizeof (psize));
+				zdb_nicenum(zb->zb_asize, asize,
+				    sizeof (asize));
+				zdb_nicenum(zb->zb_asize / zb->zb_count, avg,
+				    sizeof (avg));
+				zdb_nicenum(zb->zb_gangs, gang, sizeof (gang));
 
 				(void) printf("%6s\t%5s\t%5s\t%5s\t%5s"
 				    "\t%5.2f\t%6.2f\t",
diff --git a/usr/src/cmd/ztest/ztest.c b/usr/src/cmd/ztest/ztest.c
index f83db2d139..32ecef6b18 100644
--- a/usr/src/cmd/ztest/ztest.c
+++ b/usr/src/cmd/ztest/ztest.c
@@ -24,6 +24,7 @@
  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  * Copyright (c) 2014 Integros [integros.com]
+ * Copyright 2017 Joyent, Inc.
  */
 
 /*
@@ -123,6 +124,7 @@
 #include <math.h>
 #include <sys/fs/zfs.h>
 #include <libnvpair.h>
+#include <libcmdutils.h>
 
 static int ztest_fd_data = -1;
 static int ztest_fd_rand = -1;
@@ -554,12 +556,13 @@ usage(boolean_t requested)
 {
 	const ztest_shared_opts_t *zo = &ztest_opts_defaults;
 
-	char nice_vdev_size[10];
-	char nice_gang_bang[10];
+	char nice_vdev_size[NN_NUMBUF_SZ];
+	char nice_gang_bang[NN_NUMBUF_SZ];
 	FILE *fp = requested ? stdout : stderr;
 
-	nicenum(zo->zo_vdev_size, nice_vdev_size);
-	nicenum(zo->zo_metaslab_gang_bang, nice_gang_bang);
+	nicenum(zo->zo_vdev_size, nice_vdev_size, sizeof (nice_vdev_size));
+	nicenum(zo->zo_metaslab_gang_bang, nice_gang_bang,
+	    sizeof (nice_gang_bang));
 
 	(void) fprintf(fp, "Usage: %s\n"
 	    "\t[-v vdevs (default: %llu)]\n"
@@ -3156,10 +3159,10 @@ ztest_vdev_LUN_growth(ztest_ds_t *zd, uint64_t id)
 		    old_class_space, new_class_space);
 
 	if (ztest_opts.zo_verbose >= 5) {
-		char oldnumbuf[6], newnumbuf[6];
+		char oldnumbuf[NN_NUMBUF_SZ], newnumbuf[NN_NUMBUF_SZ];
 
-		nicenum(old_class_space, oldnumbuf);
-		nicenum(new_class_space, newnumbuf);
+		nicenum(old_class_space, oldnumbuf, sizeof (oldnumbuf));
+		nicenum(new_class_space, newnumbuf, sizeof (newnumbuf));
 		(void) printf("%s grew from %s to %s\n",
 		    spa->spa_name, oldnumbuf, newnumbuf);
 	}
@@ -6201,7 +6204,7 @@ main(int argc, char **argv)
 	ztest_info_t *zi;
 	ztest_shared_callstate_t *zc;
 	char timebuf[100];
-	char numbuf[6];
+	char numbuf[NN_NUMBUF_SZ];
 	spa_t *spa;
 	char *cmd;
 	boolean_t hasalt;
@@ -6338,7 +6341,7 @@ main(int argc, char **argv)
 
 			now = MIN(now, zs->zs_proc_stop);
 			print_time(zs->zs_proc_stop - now, timebuf);
-			nicenum(zs->zs_space, numbuf);
+			nicenum(zs->zs_space, numbuf, sizeof (numbuf));
 
 			(void) printf("Pass %3d, %8s, %3llu ENOSPC, "
 			    "%4.1f%% of %5s used, %3.0f%% done, %8s to go\n",
diff --git a/usr/src/lib/libcmdutils/Makefile.com b/usr/src/lib/libcmdutils/Makefile.com
index ffe3c9cba5..9cb35f8795 100644
--- a/usr/src/lib/libcmdutils/Makefile.com
+++ b/usr/src/lib/libcmdutils/Makefile.com
@@ -26,7 +26,7 @@
 LIBRARY=	libcmdutils.a
 VERS=		.1
 CMD_OBJS=	avltree.o sysattrs.o writefile.o process_xattrs.o uid.o gid.o \
-		custr.o
+		custr.o nicenum.o
 COM_OBJS=	list.o
 OBJECTS=	$(CMD_OBJS) $(COM_OBJS)
 
diff --git a/usr/src/lib/libcmdutils/common/mapfile-vers b/usr/src/lib/libcmdutils/common/mapfile-vers
index 1f63d4eee0..0ac77eb010 100644
--- a/usr/src/lib/libcmdutils/common/mapfile-vers
+++ b/usr/src/lib/libcmdutils/common/mapfile-vers
@@ -72,6 +72,8 @@ SYMBOL_VERSION SUNWprivate_1.1 {
 	list_remove_head;
 	list_remove_tail;
 	list_tail;
+	nicenum;
+	nicenum_scale;
 	tnode_compare;
 	sysattr_type;
 	sysattr_support;
diff --git a/usr/src/lib/libcmdutils/common/nicenum.c b/usr/src/lib/libcmdutils/common/nicenum.c
new file mode 100644
index 0000000000..8e3202f792
--- /dev/null
+++ b/usr/src/lib/libcmdutils/common/nicenum.c
@@ -0,0 +1,130 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright 2017 Jason king
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/debug.h>
+#include "libcmdutils.h"
+
+/* The largest suffix that can fit, aka an exabyte (2^60 / 10^18) */
+#define	INDEX_MAX	(6)
+
+/* Verify INDEX_MAX fits */
+CTASSERT(INDEX_MAX * 10 < sizeof (uint64_t) * 8);
+
+void
+nicenum_scale(uint64_t n, size_t units, char *buf, size_t buflen,
+    uint32_t flags)
+{
+	uint64_t divamt = 1024;
+	uint64_t divisor = 1;
+	int index = 0;
+	int rc = 0;
+	char u;
+
+	if (units == 0)
+		units = 1;
+
+	if (n > 0) {
+		n *= units;
+		if (n < units)
+			goto overflow;
+	}
+
+	if (flags & NN_DIVISOR_1000)
+		divamt = 1000;
+
+	/*
+	 * This tries to find the suffix S(n) such that
+	 * S(n) <= n < S(n+1), where S(n) = 2^(n*10) | 10^(3*n)
+	 * (i.e. 1024/1000, 1,048,576/1,000,000, etc).  Stop once S(n)
+	 * is the largest prefix supported (i.e. don't bother computing
+	 * and checking S(n+1).  Since INDEX_MAX should be the largest
+	 * suffix that fits (currently an exabyte), S(INDEX_MAX + 1) is
+	 * never checked as it would overflow.
+	 */
+	while (index < INDEX_MAX) {
+		uint64_t newdiv = divisor * divamt;
+
+		/* CTASSERT() guarantee these never trip */
+		VERIFY3U(newdiv, >=, divamt);
+		VERIFY3U(newdiv, >=, divisor);
+
+		if (n < newdiv)
+			break;
+
+		divisor = newdiv;
+		index++;
+	}
+
+	u = " KMGTPE"[index];
+
+	if (index == 0) {
+		rc = snprintf(buf, buflen, "%llu", n);
+	} else if (n % divisor == 0) {
+		/*
+		 * If this is an even multiple of the base, always display
+		 * without any decimal precision.
+		 */
+		rc = snprintf(buf, buflen, "%llu%c", n / divisor, u);
+	} else {
+		/*
+		 * We want to choose a precision that reflects the best choice
+		 * for fitting in 5 characters.  This can get rather tricky
+		 * when we have numbers that are very close to an order of
+		 * magnitude.  For example, when displaying 10239 (which is
+		 * really 9.999K), we want only a single place of precision
+		 * for 10.0K.  We could develop some complex heuristics for
+		 * this, but it's much easier just to try each combination
+		 * in turn.
+		 */
+		int i;
+		for (i = 2; i >= 0; i--) {
+			if ((rc = snprintf(buf, buflen, "%.*f%c", i,
+			    (double)n / divisor, u)) <= 5)
+				break;
+		}
+	}
+
+	if (rc + 1 > buflen || rc < 0)
+		goto overflow;
+
+	return;
+
+overflow:
+	/* prefer a more verbose message if possible */
+	if (buflen > 10)
+		(void) strlcpy(buf, "<overflow>", buflen);
+	else
+		(void) strlcpy(buf, "??", buflen);
+}
+
+void
+nicenum(uint64_t num, char *buf, size_t buflen)
+{
+	nicenum_scale(num, 1, buf, buflen, 0);
+}
diff --git a/usr/src/lib/libcmdutils/libcmdutils.h b/usr/src/lib/libcmdutils/libcmdutils.h
index 933ceb0fde..5f9957b861 100644
--- a/usr/src/lib/libcmdutils/libcmdutils.h
+++ b/usr/src/lib/libcmdutils/libcmdutils.h
@@ -216,6 +216,14 @@ extern void custr_reset(custr_t *);
  */
 extern const char *custr_cstr(custr_t *str);
 
+#define	NN_DIVISOR_1000		(1U << 0)
+
+/* Minimum size for the output of nicenum, including NULL */
+#define	NN_NUMBUF_SZ		(6)
+
+void nicenum(uint64_t, char *, size_t);
+void nicenum_scale(uint64_t, size_t, char *, size_t, uint32_t);
+
 #ifdef	__cplusplus
 }
 #endif
diff --git a/usr/src/lib/libzfs/Makefile.com b/usr/src/lib/libzfs/Makefile.com
index 31619b01c1..6eaf4332f2 100644
--- a/usr/src/lib/libzfs/Makefile.com
+++ b/usr/src/lib/libzfs/Makefile.com
@@ -70,7 +70,7 @@ INCS += -I../../libc/inc
 C99MODE=	-xc99=%all
 C99LMODE=	-Xc99=%all
 LDLIBS +=	-lc -lm -ldevid -lgen -lnvpair -luutil -lavl -lefi \
-	-ladm -lidmap -ltsol -lmd -lumem -lzfs_core
+	-ladm -lidmap -ltsol -lmd -lumem -lzfs_core -lcmdutils
 CPPFLAGS +=	$(INCS) -D_LARGEFILE64_SOURCE=1 -D_REENTRANT
 $(NOT_RELEASE_BUILD)CPPFLAGS += -DDEBUG
 
diff --git a/usr/src/lib/libzfs/common/libzfs_util.c b/usr/src/lib/libzfs/common/libzfs_util.c
index bcb48094f6..aba044add5 100644
--- a/usr/src/lib/libzfs/common/libzfs_util.c
+++ b/usr/src/lib/libzfs/common/libzfs_util.c
@@ -45,6 +45,7 @@
 #include <sys/mnttab.h>
 #include <sys/mntent.h>
 #include <sys/types.h>
+#include <libcmdutils.h>
 
 #include <libzfs.h>
 #include <libzfs_core.h>
@@ -572,42 +573,7 @@ zfs_strdup(libzfs_handle_t *hdl, const char *str)
 void
 zfs_nicenum(uint64_t num, char *buf, size_t buflen)
 {
-	uint64_t n = num;
-	int index = 0;
-	char u;
-
-	while (n >= 1024) {
-		n /= 1024;
-		index++;
-	}
-
-	u = " KMGTPE"[index];
-
-	if (index == 0) {
-		(void) snprintf(buf, buflen, "%llu", n);
-	} else if ((num & ((1ULL << 10 * index) - 1)) == 0) {
-		/*
-		 * If this is an even multiple of the base, always display
-		 * without any decimal precision.
-		 */
-		(void) snprintf(buf, buflen, "%llu%c", n, u);
-	} else {
-		/*
-		 * We want to choose a precision that reflects the best choice
-		 * for fitting in 5 characters.  This can get rather tricky when
-		 * we have numbers that are very close to an order of magnitude.
-		 * For example, when displaying 10239 (which is really 9.999K),
-		 * we want only a single place of precision for 10.0K.  We could
-		 * develop some complex heuristics for this, but it's much
-		 * easier just to try each combination in turn.
-		 */
-		int i;
-		for (i = 2; i >= 0; i--) {
-			if (snprintf(buf, buflen, "%.*f%c", i,
-			    (double)num / (1ULL << 10 * index), u) <= 5)
-				break;
-		}
-	}
+	nicenum(num, buf, buflen);
 }
 
 void
diff --git a/usr/src/lib/libzpool/common/llib-lzpool b/usr/src/lib/libzpool/common/llib-lzpool
index 3636b4e76e..27d01fd54d 100644
--- a/usr/src/lib/libzpool/common/llib-lzpool
+++ b/usr/src/lib/libzpool/common/llib-lzpool
@@ -62,6 +62,7 @@
 #include <sys/dsl_userhold.h>
 #include <sys/blkptr.h>
 #include <sys/abd.h>
+#include <libcmdutils.h>
 
 extern uint64_t metaslab_gang_bang;
 extern uint64_t metaslab_df_alloc_threshold;
diff --git a/usr/src/lib/libzpool/common/sys/zfs_context.h b/usr/src/lib/libzpool/common/sys/zfs_context.h
index b858ea719b..6e063b9c17 100644
--- a/usr/src/lib/libzpool/common/sys/zfs_context.h
+++ b/usr/src/lib/libzpool/common/sys/zfs_context.h
@@ -543,7 +543,7 @@ extern void kernel_init(int);
 extern void kernel_fini(void);
 
 struct spa;
-extern void nicenum(uint64_t num, char *buf);
+extern void nicenum(uint64_t num, char *buf, size_t);
 extern void show_pool_stats(struct spa *);
 extern int set_global_var(char *arg);
 
diff --git a/usr/src/lib/libzpool/common/util.c b/usr/src/lib/libzpool/common/util.c
index e929aa5645..363940677c 100644
--- a/usr/src/lib/libzpool/common/util.c
+++ b/usr/src/lib/libzpool/common/util.c
@@ -38,33 +38,6 @@
  * Routines needed by more than one client of libzpool.
  */
 
-void
-nicenum(uint64_t num, char *buf)
-{
-	uint64_t n = num;
-	int index = 0;
-	char u;
-
-	while (n >= 1024) {
-		n = (n + (1024 / 2)) / 1024; /* Round up or down */
-		index++;
-	}
-
-	u = " KMGTPE"[index];
-
-	if (index == 0) {
-		(void) sprintf(buf, "%llu", (u_longlong_t)n);
-	} else if (n < 10 && (num & (num - 1)) != 0) {
-		(void) sprintf(buf, "%.2f%c",
-		    (double)num / (1ULL << 10 * index), u);
-	} else if (n < 100 && (num & (num - 1)) != 0) {
-		(void) sprintf(buf, "%.1f%c",
-		    (double)num / (1ULL << 10 * index), u);
-	} else {
-		(void) sprintf(buf, "%llu%c", (u_longlong_t)n, u);
-	}
-}
-
 static void
 show_vdev_stats(const char *desc, const char *ctype, nvlist_t *nv, int indent)
 {
@@ -97,15 +70,17 @@ show_vdev_stats(const char *desc, const char *ctype, nvlist_t *nv, int indent)
 
 		sec = MAX(1, vs->vs_timestamp / NANOSEC);
 
-		nicenum(vs->vs_alloc, used);
-		nicenum(vs->vs_space - vs->vs_alloc, avail);
-		nicenum(vs->vs_ops[ZIO_TYPE_READ] / sec, rops);
-		nicenum(vs->vs_ops[ZIO_TYPE_WRITE] / sec, wops);
-		nicenum(vs->vs_bytes[ZIO_TYPE_READ] / sec, rbytes);
-		nicenum(vs->vs_bytes[ZIO_TYPE_WRITE] / sec, wbytes);
-		nicenum(vs->vs_read_errors, rerr);
-		nicenum(vs->vs_write_errors, werr);
-		nicenum(vs->vs_checksum_errors, cerr);
+		nicenum(vs->vs_alloc, used, sizeof (used));
+		nicenum(vs->vs_space - vs->vs_alloc, avail, sizeof (avail));
+		nicenum(vs->vs_ops[ZIO_TYPE_READ] / sec, rops, sizeof (rops));
+		nicenum(vs->vs_ops[ZIO_TYPE_WRITE] / sec, wops, sizeof (wops));
+		nicenum(vs->vs_bytes[ZIO_TYPE_READ] / sec, rbytes,
+		    sizeof (rbytes));
+		nicenum(vs->vs_bytes[ZIO_TYPE_WRITE] / sec, wbytes,
+		    sizeof (wbytes));
+		nicenum(vs->vs_read_errors, rerr, sizeof (rerr));
+		nicenum(vs->vs_write_errors, werr, sizeof (werr));
+		nicenum(vs->vs_checksum_errors, cerr, sizeof (cerr));
 
 		(void) printf("%*s%s%*s%*s%*s %5s %5s %5s %5s %5s %5s %5s\n",
 		    indent, "",