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/* vi: set sw=4 ts=4: */
/*
* Mini watch implementation for busybox
*
* Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de>
* Copyrigjt (C) Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org)
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config WATCH
//config: bool "watch (4.1 kb)"
//config: default y
//config: help
//config: watch is used to execute a program periodically, showing
//config: output to the screen.
//applet:IF_WATCH(APPLET(watch, BB_DIR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_WATCH) += watch.o
//usage:#define watch_trivial_usage
//usage: "[-n SEC] [-t] PROG ARGS"
//usage:#define watch_full_usage "\n\n"
//usage: "Run PROG periodically\n"
//usage: "\n -n Loop period in seconds (default 2)"
//usage: "\n -t Don't print header"
//usage:
//usage:#define watch_example_usage
//usage: "$ watch date\n"
//usage: "Mon Dec 17 10:31:40 GMT 2000\n"
//usage: "Mon Dec 17 10:31:42 GMT 2000\n"
//usage: "Mon Dec 17 10:31:44 GMT 2000"
/* BB_AUDIT SUSv3 N/A */
/* BB_AUDIT GNU defects -- only option -n is supported. */
#include "libbb.h"
#define ESC "\033"
// procps 2.0.18:
// watch [-d] [-n seconds]
// [--differences[=cumulative]] [--interval=seconds] command
//
// procps-3.2.3:
// watch [-dt] [-n seconds]
// [--differences[=cumulative]] [--interval=seconds] [--no-title] command
//
// (procps 3.x and procps 2.x are forks, not newer/older versions of the same)
int watch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int watch_main(int argc UNUSED_PARAM, char **argv)
{
unsigned opt;
unsigned period = 2;
unsigned width, new_width;
char *header;
char *cmd;
#if 0 // maybe ENABLE_DESKTOP?
// procps3 compat - "echo TEST | watch cat" doesn't show TEST:
close(STDIN_FILENO);
xopen("/dev/null", O_RDONLY);
#endif
// "+": stop at first non-option (procps 3.x only); -n NUM
// at least one param
opt = getopt32(argv, "^+" "dtn:+" "\0" "-1", &period);
argv += optind;
// watch from both procps 2.x and 3.x does concatenation. Example:
// watch ls -l "a /tmp" "2>&1" - ls won't see "a /tmp" as one param
cmd = *argv;
while (*++argv)
cmd = xasprintf("%s %s", cmd, *argv); // leaks cmd
width = (unsigned)-1; // make sure first time new_width != width
header = NULL;
while (1) {
/* home; clear to the end of screen */
printf(ESC"[H" ESC"[J");
if (!(opt & 0x2)) { // no -t
const unsigned time_len = sizeof("1234-67-90 23:56:89");
// STDERR_FILENO is procps3 compat:
// "watch ls 2>/dev/null" does not detect tty size
new_width = get_terminal_width(STDERR_FILENO);
if (new_width != width) {
width = new_width;
free(header);
header = xasprintf("Every %us: %-*s", period, (int)width, cmd);
}
if (time_len < width) {
strftime_YYYYMMDDHHMMSS(
header + width - time_len,
time_len,
/*time_t*:*/ NULL
);
}
// compat: empty line between header and cmd output
printf("%s\n\n", header);
}
fflush_all();
// TODO: 'real' watch pipes cmd's output to itself
// and does not allow it to overflow the screen
// (taking into account linewrap!)
system(cmd);
sleep(period);
}
return 0; // gcc thinks we can reach this :)
}
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