Improve size readability.

Preserve more space for swap devise names.
Prevent line overflow with long devise name.
Don't draw a bar when swap is not used at all.
Simplify and optimize code.
Change the label to end at end of 100%.
PR:		251655
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D27496

(cherry picked from commit 8d06c3e7a40831ac139d83b85b282206229b426f)

4 files changed, 51 insertions, 92 deletions

diff --git a/lib/libc/gen/getbsize.3 b/lib/libc/gen/getbsize.3
index c0b46bf9e235..acbe409a8456 100644
--- a/lib/libc/gen/getbsize.3
+++ b/lib/libc/gen/getbsize.3
@@ -45,10 +45,9 @@ The
 .Fn getbsize
 function returns a preferred block size for reporting by system utilities
 .Xr df 1 ,
-.Xr du 1 ,
-.Xr ls 1
+.Xr du 1
 and
-.Xr systat 1 ,
+.Xr ls 1 ,
 based on the value of the
 .Ev BLOCKSIZE
 environment variable.
diff --git a/usr.bin/systat/extern.h b/usr.bin/systat/extern.h
index 6e3117bece4e..322065f79312 100644
--- a/usr.bin/systat/extern.h
+++ b/usr.bin/systat/extern.h
@@ -168,6 +168,7 @@ char	*sysctl_dynread(const char *, size_t *);
 void	 sysputpage(WINDOW* , int, int, int, uint64_t, int);
 void	 sysputspaces(WINDOW* , int, int, int);
 void	 sysputstrs(WINDOW* , int, int, int);
+void	 sysputXs(WINDOW* , int, int, int);
 void	 sysputuint64(WINDOW* , int, int, int, uint64_t, int);
 void	 sysputwuint64(WINDOW* , int, int, int, uint64_t, int);
 
diff --git a/usr.bin/systat/swap.c b/usr.bin/systat/swap.c
index fc44db7d7d42..29b04df0157f 100644
--- a/usr.bin/systat/swap.c
+++ b/usr.bin/systat/swap.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 1980, 1992, 1993
  *	The Regents of the University of California.  All rights reserved.
- * Copyright (c) 2017 Yoshihiro Ota
+ * Copyright (c) 2017, 2020 Yoshihiro Ota
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -58,22 +58,19 @@ static const char sccsid[] = "@(#)swap.c	8.3 (Berkeley) 4/29/95";
 #include "extern.h"
 #include "devs.h"
 
-static char *header;
-static long blocksize;
-static int dlen, odlen;
-static int hlen;
-static int ulen, oulen;
-static int pagesize;
+static int pathlen;
 
 WINDOW *
 openswap(void)
 {
-	return (subwin(stdscr, LINES-3-1, 0, MAINWIN_ROW, 0));
+
+	return (subwin(stdscr, LINES - 3 - 1, 0, MAINWIN_ROW, 0));
 }
 
 void
 closeswap(WINDOW *w)
 {
+
 	if (w == NULL)
 		return;
 	wclear(w);
@@ -92,29 +89,6 @@ closeswap(WINDOW *w)
 static struct kvm_swap kvmsw[NSWAP];
 static int kvnsw, okvnsw;
 
-static void calclens(void);
-
-#define CONVERT(v)	((int)((int64_t)(v) * pagesize / blocksize))
-
-static void
-calclens(void)
-{
-	int i, n;
-	int len;
-
-	dlen = sizeof("Disk");
-	for (i = 0; i < kvnsw; ++i) {
-		len = strlen(kvmsw[i].ksw_devname);
-		if (dlen < len)
-			dlen = len;
-	}
-
-	ulen = sizeof("Used");
-	for (n = CONVERT(kvmsw[kvnsw].ksw_used), len = 2; n /= 10; ++len);
-	if (ulen < len)
-		ulen = len;
-}
-
 int
 initswap(void)
 {
@@ -123,22 +97,13 @@ initswap(void)
 	if (once)
 		return (1);
 
-	header = getbsize(&hlen, &blocksize);
-	pagesize = getpagesize();
-
 	if ((kvnsw = kvm_getswapinfo(kd, kvmsw, NSWAP, 0)) < 0) {
 		error("systat: kvm_getswapinfo failed");
 		return (0);
 	}
-	okvnsw = kvnsw;
-
-	calclens();
-	odlen = dlen;
-	oulen = ulen;
-
-	once = 1;
-
+	pathlen = 80 - 50 /* % */ - 5 /* Used */ - 5 /* Size */ - 3 /* space */;
 	dsinit(12);
+	once = 1;
 
 	return (1);
 }
@@ -146,16 +111,13 @@ initswap(void)
 void
 fetchswap(void)
 {
+
 	okvnsw = kvnsw;
 	if ((kvnsw = kvm_getswapinfo(kd, kvmsw, NSWAP, 0)) < 0) {
 		error("systat: kvm_getswapinfo failed");
 		return;
 	}
 
-	odlen = dlen;
-	oulen = ulen;
-	calclens();
-
 	struct devinfo *tmp_dinfo;
 
 	tmp_dinfo = last_dev.dinfo;
@@ -172,24 +134,23 @@ labelswap(void)
 	const char *name;
 	int i;
 
-	fetchswap();
-
 	werase(wnd);
 
-	mvwprintw(wnd, 0, 0, "%*s%*s%*s %s",
-	    -dlen, "Disk", hlen, header, ulen, "Used",
-	    "/0%  /10  /20  /30  /40  /50  /60  /70  /80  /90  /100");
+	dslabel(12, 0, 18);
+
+	if (kvnsw <= 0) {
+		mvwprintw(wnd, 0, 0, "(swap not configured)");
+		return;
+	}
+
+	mvwprintw(wnd, 0, 0, "%*s%5s %5s %s",
+	    -pathlen, "Device/Path", "Size", "Used",
+	    "|0%  /10  /20  /30  /40  / 60\\  70\\  80\\  90\\ 100|");
 
 	for (i = 0; i <= kvnsw; ++i) {
-		if (i == kvnsw) {
-			if (kvnsw == 1)
-				break;
-			name = "Total";
-		} else
-			name = kvmsw[i].ksw_devname;
-		mvwprintw(wnd, i + 1, 0, "%*s", -dlen, name);
+		name = i == kvnsw ? "Total" : kvmsw[i].ksw_devname;
+		mvwprintw(wnd, 1 + i, 0, "%-*.*s", pathlen, pathlen - 1, name);
 	}
-	dslabel(12, 0, 18);
 }
 
 void
@@ -198,36 +159,23 @@ showswap(void)
 	int count;
 	int i;
 
-	if (kvnsw != okvnsw || dlen != odlen || ulen != oulen)
+	if (kvnsw != okvnsw)
 		labelswap();
 
-	for (i = 0; i <= kvnsw; ++i) {
-		if (i == kvnsw) {
-			if (kvnsw == 1)
-				break;
-		}
-
-		if (kvmsw[i].ksw_total == 0) {
-			mvwprintw(
-			    wnd,
-			    i + 1,
-			    dlen + hlen + ulen + 1,
-			    "(swap not configured)"
-			);
-			continue;
-		}
-
-		wmove(wnd, i + 1, dlen);
+	dsshow(12, 0, 18, &cur_dev, &last_dev);
 
-		wprintw(wnd, "%*d", hlen, CONVERT(kvmsw[i].ksw_total));
-		wprintw(wnd, "%*d", ulen, CONVERT(kvmsw[i].ksw_used));
+	if (kvnsw <= 0)
+		return;
 
-		count = 50.0 * kvmsw[i].ksw_used / kvmsw[i].ksw_total + 1;
+	for (i = 0; i <= kvnsw; ++i) {
+		sysputpage(wnd, i + 1, pathlen, 5, kvmsw[i].ksw_total, 0);
+		sysputpage(wnd, i + 1, pathlen + 5 + 1, 5, kvmsw[i].ksw_used,
+		    0);
 
-		waddch(wnd, ' ');
-		while (count--)
-			waddch(wnd, 'X');
+		if (kvmsw[i].ksw_used > 0) {
+			count = 50 * kvmsw[i].ksw_used / kvmsw[i].ksw_total;
+			sysputXs(wnd, i + 1, pathlen + 5 + 1 + 5 + 1, count);
+		}
 		wclrtoeol(wnd);
 	}
-	dsshow(12, 0, 18, &cur_dev, &last_dev);
 }
diff --git a/usr.bin/systat/sysput.c b/usr.bin/systat/sysput.c
index 31c9127a83b7..10401cee772a 100644
--- a/usr.bin/systat/sysput.c
+++ b/usr.bin/systat/sysput.c
@@ -1,5 +1,5 @@
 /*-
- * Copyright (c) 2019 Yoshihiro Ota
+ * Copyright (c) 2019, 2020 Yoshihiro Ota
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -43,17 +43,28 @@ __FBSDID("$FreeBSD$");
 void
 sysputspaces(WINDOW *wd, int row, int col, int width)
 {
-	static char str40[] = "                                        ";
+	static char str60[] = "                    "
+	    "                                        ";
 
-	mvwaddstr(wd, row, col, str40 + sizeof(str40) - width - 1);
+	mvwaddstr(wd, row, col, str60 + sizeof(str60) - width - 1);
 }
 
 void
 sysputstrs(WINDOW *wd, int row, int col, int width)
 {
-	static char str40[] = "****************************************";
+	static char str60[] = "********************"
+	    "****************************************";
 
-	mvwaddstr(wnd, row, col, str40 + sizeof(str40) - width - 1);
+	mvwaddstr(wnd, row, col, str60 + sizeof(str60) - width - 1);
+}
+
+void
+sysputXs(WINDOW *wd, int row, int col, int width)
+{
+	static char str60[] = "XXXXXXXXXXXXXXXXXXXX"
+	    "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
+
+	mvwaddstr(wnd, row, col, str60 + sizeof(str60) - width - 1);
 }
 
 void