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Repeat iostat header after rows-3 instead of a hardcoded 20.

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Use ioctl() to get the window size in iostat(8), and force a new
header to be prepended to the output every time the current
window size changes.  Change the number of lines before each
header to `rows - 3' when the terminal is resized, so that the
full terminal length can be used for output lines.

PR:		bin/119705
Submitted by:	keramida
Approved by:	maxim
MFC after:	2 weeks
This commit is contained in:
Giorgos Keramidas 2008-01-22 11:18:51 +00:00
parent d52a94aaf8
commit 53fbcd3a78
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=175562
1 changed files with 71 additions and 3 deletions
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74
usr.sbin/iostat/iostat.c
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@ -113,6 +113,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <limits.h>
#include <devstat.h>
@ -131,17 +132,23 @@ struct nlist namelist[] = {
{ NULL },
};
#define IOSTAT_DEFAULT_ROWS 20 /* Traditional default `wrows' */
struct statinfo cur, last;
int num_devices;
struct device_selection *dev_select;
int maxshowdevs;
volatile sig_atomic_t headercount;
volatile sig_atomic_t wresized; /* Tty resized, when non-zero. */
unsigned short wrows; /* Current number of tty rows. */
int dflag = 0, Iflag = 0, Cflag = 0, Tflag = 0, oflag = 0, Kflag = 0;
int xflag = 0, zflag = 0;
/* local function declarations */
static void usage(void);
static void needhdr(int signo);
static void needresize(int signo);
static void doresize(void);
static void phdr(void);
static void devstats(int perf_select, long double etime, int havelast);
static void cpustats(void);
@ -426,6 +433,20 @@ main(int argc, char **argv)
*/
(void)signal(SIGCONT, needhdr);
/*
* If our standard output is a tty, then install a SIGWINCH handler
* and set wresized so that our first iteration through the main
* iostat loop will peek at the terminal's current rows to find out
* how many lines can fit in a screenful of output.
*/
if (isatty(fileno(stdout)) != 0) {
wresized = 1;
(void)signal(SIGWINCH, needresize);
} else {
wresized = 0;
wrows = IOSTAT_DEFAULT_ROWS;
}
for (headercount = 1;;) {
struct devinfo *tmp_dinfo;
long tmp;
@ -451,7 +472,9 @@ main(int argc, char **argv)
if (!--headercount) {
phdr();
headercount = 20;
if (wresized != 0)
doresize();
headercount = wrows;
}
tmp_dinfo = last.dinfo;
@ -493,7 +516,9 @@ main(int argc, char **argv)
break;
case 1:
phdr();
headercount = 20;
if (wresized != 0)
doresize();
headercount = wrows;
break;
default:
break;
@ -528,7 +553,9 @@ main(int argc, char **argv)
break;
case 1:
phdr();
headercount = 20;
if (wresized != 0)
doresize();
headercount = wrows;
break;
default:
break;
@ -589,6 +616,47 @@ needhdr(int signo)
headercount = 1;
}
/*
* When the terminal is resized, force an update of the maximum number of rows
* printed between each header repetition. Then force a new header to be
* prepended to the next output.
*/
void
needresize(int signo)
{
wresized = 1;
headercount = 1;
}
/*
* Update the global `wrows' count of terminal rows.
*/
void
doresize(void)
{
int status;
struct winsize w;
for (;;) {
status = ioctl(fileno(stdout), TIOCGWINSZ, &w);
if (status == -1 && errno == EINTR)
continue;
else if (status == -1)
err(1, "ioctl");
if (w.ws_row > 3)
wrows = w.ws_row - 3;
else
wrows = IOSTAT_DEFAULT_ROWS;
break;
}
/*
* Inhibit doresize() calls until we are rescheduled by SIGWINCH.
*/
wresized = 0;
}
static void
phdr(void)
{