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