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