1/* vi: set sw=4 ts=4: */ 2/* 3 * Mini watch implementation for busybox 4 * 5 * Copyright (C) 2001 by Michael Habermann <mhabermann@gmx.de> 6 * Copyrigjt (C) Mar 16, 2003 Manuel Novoa III (mjn3@codepoet.org) 7 * 8 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. 9 */ 10 11/* BB_AUDIT SUSv3 N/A */ 12/* BB_AUDIT GNU defects -- only option -n is supported. */ 13 14#include "libbb.h" 15 16// procps 2.0.18: 17// watch [-d] [-n seconds] 18// [--differences[=cumulative]] [--interval=seconds] command 19// 20// procps-3.2.3: 21// watch [-dt] [-n seconds] 22// [--differences[=cumulative]] [--interval=seconds] [--no-title] command 23// 24// (procps 3.x and procps 2.x are forks, not newer/older versions of the same) 25 26int watch_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 27int watch_main(int argc UNUSED_PARAM, char **argv) 28{ 29 unsigned opt; 30 unsigned period = 2; 31 unsigned width, new_width; 32 char *header; 33 char *cmd; 34 35#if 0 // maybe ENABLE_DESKTOP? 36 // procps3 compat - "echo TEST | watch cat" doesn't show TEST: 37 close(STDIN_FILENO); 38 xopen("/dev/null", O_RDONLY); 39#endif 40 41 opt_complementary = "-1:n+"; // at least one param; -n NUM 42 // "+": stop at first non-option (procps 3.x only) 43 opt = getopt32(argv, "+dtn:", &period); 44 argv += optind; 45 46 // watch from both procps 2.x and 3.x does concatenation. Example: 47 // watch ls -l "a /tmp" "2>&1" - ls won't see "a /tmp" as one param 48 cmd = *argv; 49 while (*++argv) 50 cmd = xasprintf("%s %s", cmd, *argv); // leaks cmd 51 52 width = (unsigned)-1; // make sure first time new_width != width 53 header = NULL; 54 while (1) { 55 /* home; clear to the end of screen */ 56 printf("\033[H""\033[J"); 57 if (!(opt & 0x2)) { // no -t 58 const unsigned time_len = sizeof("1234-67-90 23:56:89"); 59 time_t t; 60 61 // STDERR_FILENO is procps3 compat: 62 // "watch ls 2>/dev/null" does not detect tty size 63 get_terminal_width_height(STDERR_FILENO, &new_width, NULL); 64 if (new_width != width) { 65 width = new_width; 66 free(header); 67 header = xasprintf("Every %us: %-*s", period, (int)width, cmd); 68 } 69 time(&t); 70 if (time_len < width) 71 strftime(header + width - time_len, time_len, 72 "%Y-%m-%d %H:%M:%S", localtime(&t)); 73 74 // compat: empty line between header and cmd output 75 printf("%s\n\n", header); 76 } 77 fflush_all(); 78 // TODO: 'real' watch pipes cmd's output to itself 79 // and does not allow it to overflow the screen 80 // (taking into account linewrap!) 81 system(cmd); 82 sleep(period); 83 } 84 return 0; // gcc thinks we can reach this :) 85} 86