| 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * tac implementation for busybox
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| 4 | *
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| 5 | * Copyright (C) 2003 Yang Xiaopeng <yxp at hanwang.com.cn>
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| 6 | * Copyright (C) 2007 Natanael Copa <natanael.copa@gmail.com>
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| 7 | * Copyright (C) 2007 Tito Ragusa <farmatito@tiscali.it>
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| 8 | *
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| 9 | * Licensed under GPLv2, see file LICENSE in this source tree.
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| 10 | *
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| 11 | */
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| 12 |
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| 13 | /* tac - concatenate and print files in reverse */
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| 14 |
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| 15 | /* Based on Yang Xiaopeng's (yxp at hanwang.com.cn) patch
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| 16 | * http://www.uclibc.org/lists/busybox/2003-July/008813.html
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| 17 | */
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| 18 |
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| 19 | //usage:#define tac_trivial_usage
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| 20 | //usage: "[FILE]..."
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| 21 | //usage:#define tac_full_usage "\n\n"
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| 22 | //usage: "Concatenate FILEs and print them in reverse"
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| 23 |
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| 24 | #include "libbb.h"
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| 25 |
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| 26 | /* This is a NOEXEC applet. Be very careful! */
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| 27 |
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| 28 | struct lstring {
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| 29 | int size;
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| 30 | char buf[1];
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| 31 | };
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| 32 |
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| 33 | int tac_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 34 | int tac_main(int argc UNUSED_PARAM, char **argv)
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| 35 | {
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| 36 | char **name;
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| 37 | FILE *f;
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| 38 | struct lstring *line = NULL;
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| 39 | llist_t *list = NULL;
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| 40 | int retval = EXIT_SUCCESS;
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| 41 |
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| 42 | #if ENABLE_DESKTOP
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| 43 | /* tac from coreutils 6.9 supports:
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| 44 | -b, --before
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| 45 | attach the separator before instead of after
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| 46 | -r, --regex
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| 47 | interpret the separator as a regular expression
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| 48 | -s, --separator=STRING
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| 49 | use STRING as the separator instead of newline
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| 50 | We support none, but at least we will complain or handle "--":
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| 51 | */
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| 52 | getopt32(argv, "");
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| 53 | argv += optind;
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| 54 | #else
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| 55 | argv++;
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| 56 | #endif
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| 57 | if (!*argv)
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| 58 | *--argv = (char *)"-";
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| 59 | /* We will read from last file to first */
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| 60 | name = argv;
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| 61 | while (*name)
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| 62 | name++;
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| 63 |
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| 64 | do {
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| 65 | int ch, i;
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| 66 |
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| 67 | name--;
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| 68 | f = fopen_or_warn_stdin(*name);
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| 69 | if (f == NULL) {
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| 70 | /* error message is printed by fopen_or_warn_stdin */
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| 71 | retval = EXIT_FAILURE;
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| 72 | continue;
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| 73 | }
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| 74 |
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| 75 | errno = i = 0;
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| 76 | do {
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| 77 | ch = fgetc(f);
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| 78 | if (ch != EOF) {
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| 79 | if (!(i & 0x7f))
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| 80 | /* Grow on every 128th char */
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| 81 | line = xrealloc(line, i + 0x7f + sizeof(int) + 1);
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| 82 | line->buf[i++] = ch;
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| 83 | }
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| 84 | if (ch == '\n' || (ch == EOF && i != 0)) {
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| 85 | line = xrealloc(line, i + sizeof(int));
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| 86 | line->size = i;
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| 87 | llist_add_to(&list, line);
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| 88 | line = NULL;
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| 89 | i = 0;
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| 90 | }
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| 91 | } while (ch != EOF);
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| 92 | /* fgetc sets errno to ENOENT on EOF, we don't want
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| 93 | * to warn on this non-error! */
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| 94 | if (errno && errno != ENOENT) {
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| 95 | bb_simple_perror_msg(*name);
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| 96 | retval = EXIT_FAILURE;
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| 97 | }
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| 98 | } while (name != argv);
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| 99 |
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| 100 | while (list) {
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| 101 | line = (struct lstring *)list->data;
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| 102 | xwrite(STDOUT_FILENO, line->buf, line->size);
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| 103 | if (ENABLE_FEATURE_CLEAN_UP) {
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| 104 | free(llist_pop(&list));
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| 105 | } else {
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| 106 | list = list->link;
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| 107 | }
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| 108 | }
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| 109 |
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| 110 | return retval;
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| 111 | }
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