[3320] | 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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