blob: 94d669de1955f474ede99a2fb3c65fe2a4895b40
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * tac implementation for busybox |
4 | * |
5 | * Copyright (C) 2003 Yang Xiaopeng <yxp at hanwang.com.cn> |
6 | * Copyright (C) 2007 Natanael Copa <natanael.copa@gmail.com> |
7 | * Copyright (C) 2007 Tito Ragusa <farmatito@tiscali.it> |
8 | * |
9 | * Licensed under GPLv2, see file LICENSE in this source tree. |
10 | * |
11 | */ |
12 | |
13 | /* tac - concatenate and print files in reverse */ |
14 | |
15 | /* Based on Yang Xiaopeng's (yxp at hanwang.com.cn) patch |
16 | * http://www.uclibc.org/lists/busybox/2003-July/008813.html |
17 | */ |
18 | |
19 | //usage:#define tac_trivial_usage |
20 | //usage: "[FILE]..." |
21 | //usage:#define tac_full_usage "\n\n" |
22 | //usage: "Concatenate FILEs and print them in reverse" |
23 | |
24 | #include "libbb.h" |
25 | |
26 | /* This is a NOEXEC applet. Be very careful! */ |
27 | |
28 | struct lstring { |
29 | int size; |
30 | char buf[1]; |
31 | }; |
32 | |
33 | int tac_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
34 | int tac_main(int argc UNUSED_PARAM, char **argv) |
35 | { |
36 | char **name; |
37 | FILE *f; |
38 | struct lstring *line = NULL; |
39 | llist_t *list = NULL; |
40 | int retval = EXIT_SUCCESS; |
41 | |
42 | #if ENABLE_DESKTOP |
43 | /* tac from coreutils 6.9 supports: |
44 | -b, --before |
45 | attach the separator before instead of after |
46 | -r, --regex |
47 | interpret the separator as a regular expression |
48 | -s, --separator=STRING |
49 | use STRING as the separator instead of newline |
50 | We support none, but at least we will complain or handle "--": |
51 | */ |
52 | getopt32(argv, ""); |
53 | argv += optind; |
54 | #else |
55 | argv++; |
56 | #endif |
57 | if (!*argv) |
58 | *--argv = (char *)"-"; |
59 | /* We will read from last file to first */ |
60 | name = argv; |
61 | while (*name) |
62 | name++; |
63 | |
64 | do { |
65 | int ch, i; |
66 | |
67 | name--; |
68 | f = fopen_or_warn_stdin(*name); |
69 | if (f == NULL) { |
70 | /* error message is printed by fopen_or_warn_stdin */ |
71 | retval = EXIT_FAILURE; |
72 | continue; |
73 | } |
74 | |
75 | errno = i = 0; |
76 | do { |
77 | ch = fgetc(f); |
78 | if (ch != EOF) { |
79 | if (!(i & 0x7f)) |
80 | /* Grow on every 128th char */ |
81 | line = xrealloc(line, i + 0x7f + sizeof(int) + 1); |
82 | line->buf[i++] = ch; |
83 | } |
84 | if (ch == '\n' || (ch == EOF && i != 0)) { |
85 | line = xrealloc(line, i + sizeof(int)); |
86 | line->size = i; |
87 | llist_add_to(&list, line); |
88 | line = NULL; |
89 | i = 0; |
90 | } |
91 | } while (ch != EOF); |
92 | /* fgetc sets errno to ENOENT on EOF, we don't want |
93 | * to warn on this non-error! */ |
94 | if (errno && errno != ENOENT) { |
95 | bb_simple_perror_msg(*name); |
96 | retval = EXIT_FAILURE; |
97 | } |
98 | } while (name != argv); |
99 | |
100 | while (list) { |
101 | line = (struct lstring *)list->data; |
102 | xwrite(STDOUT_FILENO, line->buf, line->size); |
103 | if (ENABLE_FEATURE_CLEAN_UP) { |
104 | free(llist_pop(&list)); |
105 | } else { |
106 | list = list->link; |
107 | } |
108 | } |
109 | |
110 | return retval; |
111 | } |
112 |