Annotation of /tags/mkinitrd-6_3_1/busybox/coreutils/head.c
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Thu Aug 19 12:44:27 2010 UTC (14 years, 1 month ago) by niro
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File size: 2749 byte(s)
Thu Aug 19 12:44:27 2010 UTC (14 years, 1 month ago) by niro
File MIME type: text/plain
File size: 2749 byte(s)
tagged 'mkinitrd-6_3_1'
1 | niro | 532 | /* vi: set sw=4 ts=4: */ |
2 | /* | ||
3 | * head implementation for busybox | ||
4 | * | ||
5 | * Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org> | ||
6 | * | ||
7 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. | ||
8 | */ | ||
9 | |||
10 | /* BB_AUDIT SUSv3 compliant */ | ||
11 | /* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */ | ||
12 | /* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */ | ||
13 | |||
14 | niro | 816 | #include "libbb.h" |
15 | niro | 532 | |
16 | niro | 816 | static const char head_opts[] ALIGN1 = |
17 | niro | 532 | "n:" |
18 | #if ENABLE_FEATURE_FANCY_HEAD | ||
19 | "c:qv" | ||
20 | #endif | ||
21 | ; | ||
22 | |||
23 | static const struct suffix_mult head_suffixes[] = { | ||
24 | { "b", 512 }, | ||
25 | { "k", 1024 }, | ||
26 | { "m", 1024*1024 }, | ||
27 | niro | 984 | { "", 0 } |
28 | niro | 532 | }; |
29 | |||
30 | niro | 1123 | #define header_fmt_str "\n==> %s <==\n" |
31 | niro | 532 | |
32 | niro | 816 | int head_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
33 | niro | 532 | int head_main(int argc, char **argv) |
34 | { | ||
35 | unsigned long count = 10; | ||
36 | unsigned long i; | ||
37 | #if ENABLE_FEATURE_FANCY_HEAD | ||
38 | int count_bytes = 0; | ||
39 | int header_threshhold = 1; | ||
40 | #endif | ||
41 | FILE *fp; | ||
42 | const char *fmt; | ||
43 | char *p; | ||
44 | int opt; | ||
45 | int c; | ||
46 | int retval = EXIT_SUCCESS; | ||
47 | |||
48 | #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD | ||
49 | /* Allow legacy syntax of an initial numeric option without -n. */ | ||
50 | niro | 984 | if (argv[1] && argv[1][0] == '-' |
51 | niro | 532 | && isdigit(argv[1][1]) |
52 | ) { | ||
53 | --argc; | ||
54 | ++argv; | ||
55 | p = (*argv) + 1; | ||
56 | goto GET_COUNT; | ||
57 | } | ||
58 | #endif | ||
59 | |||
60 | /* No size benefit in converting this to getopt32 */ | ||
61 | while ((opt = getopt(argc, argv, head_opts)) > 0) { | ||
62 | switch (opt) { | ||
63 | #if ENABLE_FEATURE_FANCY_HEAD | ||
64 | case 'q': | ||
65 | header_threshhold = INT_MAX; | ||
66 | break; | ||
67 | case 'v': | ||
68 | header_threshhold = -1; | ||
69 | break; | ||
70 | case 'c': | ||
71 | count_bytes = 1; | ||
72 | /* fall through */ | ||
73 | #endif | ||
74 | case 'n': | ||
75 | p = optarg; | ||
76 | #if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD | ||
77 | GET_COUNT: | ||
78 | #endif | ||
79 | count = xatoul_sfx(p, head_suffixes); | ||
80 | break; | ||
81 | default: | ||
82 | bb_show_usage(); | ||
83 | } | ||
84 | } | ||
85 | |||
86 | niro | 816 | argc -= optind; |
87 | niro | 532 | argv += optind; |
88 | niro | 816 | if (!*argv) |
89 | *--argv = (char*)"-"; | ||
90 | niro | 532 | |
91 | fmt = header_fmt_str + 1; | ||
92 | #if ENABLE_FEATURE_FANCY_HEAD | ||
93 | niro | 816 | if (argc <= header_threshhold) { |
94 | niro | 532 | header_threshhold = 0; |
95 | } | ||
96 | #else | ||
97 | niro | 816 | if (argc <= 1) { |
98 | fmt += 11; /* "" */ | ||
99 | niro | 532 | } |
100 | /* Now define some things here to avoid #ifdefs in the code below. | ||
101 | * These should optimize out of the if conditions below. */ | ||
102 | #define header_threshhold 1 | ||
103 | #define count_bytes 0 | ||
104 | #endif | ||
105 | |||
106 | do { | ||
107 | fp = fopen_or_warn_stdin(*argv); | ||
108 | if (fp) { | ||
109 | if (fp == stdin) { | ||
110 | *argv = (char *) bb_msg_standard_input; | ||
111 | } | ||
112 | if (header_threshhold) { | ||
113 | printf(fmt, *argv); | ||
114 | } | ||
115 | i = count; | ||
116 | while (i && ((c = getc(fp)) != EOF)) { | ||
117 | if (count_bytes || (c == '\n')) { | ||
118 | --i; | ||
119 | } | ||
120 | putchar(c); | ||
121 | } | ||
122 | if (fclose_if_not_stdin(fp)) { | ||
123 | niro | 984 | bb_simple_perror_msg(*argv); |
124 | niro | 532 | retval = EXIT_FAILURE; |
125 | } | ||
126 | die_if_ferror_stdout(); | ||
127 | niro | 984 | } else { |
128 | retval = EXIT_FAILURE; | ||
129 | niro | 532 | } |
130 | fmt = header_fmt_str; | ||
131 | } while (*++argv); | ||
132 | |||
133 | fflush_stdout_and_exit(retval); | ||
134 | } |