procps/watch.c

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5.7 KiB
C
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2002-02-02 04:17:29 +05:30
/* watch -- execute a program repeatedly, displaying output fullscreen
*
* Based on the original 1991 'watch' by Tony Rems <rembo@unisoft.com>
* (with mods and corrections by Francois Pinard).
*
* Substantially reworked, new features (differences option, SIGWINCH
* handling, unlimited command length, long line handling) added Apr 1999 by
* Mike Coleman <mkc@acm.org>.
*/
#define VERSION "0.2.0"
#include <ctype.h>
#include <getopt.h>
#include <signal.h>
#include <ncurses.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <time.h>
#include <unistd.h>
#include <locale.h>
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static struct option longopts[] =
{
{ "differences", optional_argument, 0, 'd' },
{ "help", no_argument, 0, 'h' },
{ "interval", required_argument, 0, 'n' },
{ "version", no_argument, 0, 'v' },
{ 0, 0, 0, 0 }
};
static char usage[] = "Usage: %s [-dhnv] [--differences[=cumulative]] [--help] [--interval=<n>] [--version] <command>\n";
static char *progname;
static int curses_started = 0;
static int height=24, width=80;
static int screen_size_changed=0;
static int first_screen=1;
#define min(x,y) ((x) > (y) ? (y) : (x))
static void
do_usage(void)
{
fprintf(stderr, usage, progname);
exit(1);
}
static void
do_exit(int status) {
if (curses_started)
endwin();
exit(status);
}
/* signal handler */
static void
die(int notused)
{
(void)notused;
do_exit(0);
}
static void
winch_handler(int notused)
{
(void)notused;
screen_size_changed = 1;
}
static void
get_terminal_size(void)
{
struct winsize w;
if (ioctl(2, TIOCGWINSZ, &w) == 0)
{
if (w.ws_row > 0)
height = w.ws_row;
if (w.ws_col > 0)
width = w.ws_col;
}
}
int
main(int argc, char *argv[])
{
int optc;
int option_differences=0,
option_differences_cumulative=0,
option_help=0,
option_version=0;
int interval=2;
char *command;
int command_length=0; /* not including final \0 */
setlocale(LC_ALL,"");
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progname = argv[0];
while ((optc = getopt_long(argc, argv, "+d::hn:v", longopts, (int *) 0))
!= EOF)
{
switch (optc)
{
case 'd':
option_differences = 1;
if (optarg)
option_differences_cumulative = 1;
break;
case 'h':
option_help = 1;
break;
case 'n':
{
char *str;
interval = strtol(optarg, &str, 10);
if (!*optarg || *str)
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do_usage();
}
break;
case 'v':
option_version = 1;
break;
default:
do_usage();
break;
}
}
if (option_version)
{
fprintf (stderr, "%s\n", VERSION);
if (!option_help)
exit(0);
}
if (option_help)
{
fprintf(stderr, usage, progname);
fputs(" -d, --differences[=cumulative]\thighlight changes between updates\n", stderr);
fputs("\t\t(cumulative means highlighting is cumulative)\n", stderr);
fputs(" -h, --help\t\t\t\tprint a summary of the options\n", stderr);
fputs(" -n, --interval=<seconds>\t\tseconds to wait between updates\n", stderr);
fputs(" -v, --version\t\t\t\tprint the version number\n", stderr);
exit(0);
}
if (optind >= argc)
do_usage();
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command = strdup(argv[optind++]);
command_length = strlen(command);
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for (;optind<argc;optind++)
{
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char *endp;
int s = strlen(argv[optind]);
command = realloc(command, command_length+s+2); /* space and \0 */
endp = command + command_length;
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*endp = ' ';
memcpy(endp+1, argv[optind],s);
command_length += 1+s; /* space then string length */
command[command_length] = '\0';
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}
get_terminal_size();
/* Catch keyboard interrupts so we can put tty back in a sane state. */
signal(SIGINT, die);
signal(SIGTERM, die);
signal(SIGHUP, die);
signal(SIGWINCH, winch_handler);
/* Set up tty for curses use. */
curses_started = 1;
initscr();
nonl();
noecho();
cbreak();
for(;;)
{
time_t t = time(NULL);
char *ts = ctime(&t);
int tsl = strlen(ts);
char *header;
FILE *p;
int x, y;
if (screen_size_changed)
{
get_terminal_size();
resizeterm(height, width);
clear();
/* redrawwin(stdscr); */
screen_size_changed = 0;
first_screen = 1;
}
/* left justify interval and command, right justify time, clipping all
to fit window width */
asprintf(&header, "Every %ds: %.*s",
interval, min(width-1, command_length), command);
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mvaddstr(0, 0, header);
if (strlen(header) > (size_t)(width - tsl - 1))
mvaddstr(0, width - tsl - 4, "... ");
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mvaddstr(0, width - tsl + 1, ts);
free(header);
if (!(p = popen(command, "r")))
{
perror("popen");
do_exit(2);
}
for (y=2; y<height; y++)
{
int eolseen = 0, tabpending = 0;
for (x=0; x<width; x++)
{
int c = ' ';
int attr = 0;
if (!eolseen)
{
/* if there is a tab pending, just spit spaces until the
next stop instead of reading characters */
if (!tabpending)
do
c = getc(p);
while (c != EOF && !isprint(c) && c != '\n' && c != '\t');
if (c == '\n')
if (x == 0) {
x=-1;
continue;
} else
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eolseen = 1;
else if (c == '\t')
tabpending = 1;
if (c == EOF || c == '\n' || c == '\t')
c = ' ';
if (tabpending && (((x + 1) % 8) == 0))
tabpending = 0;
}
move(y, x);
if (option_differences)
{
int oldch = inch();
char oldc = oldch & A_CHARTEXT;
attr = !first_screen
&& (c != oldc
|| (option_differences_cumulative
&& (oldch & A_ATTRIBUTES)));
}
if (attr)
standout();
addch(c);
if (attr)
standend();
}
}
pclose(p);
first_screen = 0;
refresh();
sleep(interval);
}
endwin();
return 0;
}