1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
/* vi: set sw=4 ts=4: */
/*
* head implementation for busybox
*
* Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */
#include "libbb.h"
static const char head_opts[] =
"n:"
#if ENABLE_FEATURE_FANCY_HEAD
"c:qv"
#endif
;
#if ENABLE_FEATURE_FANCY_HEAD
static const struct suffix_mult head_suffixes[] = {
{ "b", 512 },
{ "k", 1024 },
{ "m", 1024*1024 },
{ }
};
#endif
static const char header_fmt_str[] = "\n==> %s <==\n";
int head_main(int argc, char **argv);
int head_main(int argc, char **argv)
{
unsigned long count = 10;
unsigned long i;
#if ENABLE_FEATURE_FANCY_HEAD
int count_bytes = 0;
int header_threshhold = 1;
#endif
FILE *fp;
const char *fmt;
char *p;
int opt;
int c;
int retval = EXIT_SUCCESS;
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD
/* Allow legacy syntax of an initial numeric option without -n. */
if (argc > 1 && argv[1][0] == '-'
&& isdigit(argv[1][1])
) {
--argc;
++argv;
p = (*argv) + 1;
goto GET_COUNT;
}
#endif
/* No size benefit in converting this to getopt32 */
while ((opt = getopt(argc, argv, head_opts)) > 0) {
switch (opt) {
#if ENABLE_FEATURE_FANCY_HEAD
case 'q':
header_threshhold = INT_MAX;
break;
case 'v':
header_threshhold = -1;
break;
case 'c':
count_bytes = 1;
/* fall through */
#endif
case 'n':
p = optarg;
#if ENABLE_INCLUDE_SUSv2 || ENABLE_FEATURE_FANCY_HEAD
GET_COUNT:
#endif
#if !ENABLE_FEATURE_FANCY_HEAD
count = xatoul(p);
#else
count = xatoul_sfx(p, head_suffixes);
#endif
break;
default:
bb_show_usage();
}
}
argv += optind;
if (!*argv) {
*--argv = (char*)"-";
}
fmt = header_fmt_str + 1;
#if ENABLE_FEATURE_FANCY_HEAD
if (argc - optind <= header_threshhold) {
header_threshhold = 0;
}
#else
if (argc <= optind + 1) {
fmt += 11;
}
/* Now define some things here to avoid #ifdefs in the code below.
* These should optimize out of the if conditions below. */
#define header_threshhold 1
#define count_bytes 0
#endif
do {
fp = fopen_or_warn_stdin(*argv);
if (fp) {
if (fp == stdin) {
*argv = (char *) bb_msg_standard_input;
}
if (header_threshhold) {
printf(fmt, *argv);
}
i = count;
while (i && ((c = getc(fp)) != EOF)) {
if (count_bytes || (c == '\n')) {
--i;
}
putchar(c);
}
if (fclose_if_not_stdin(fp)) {
bb_perror_msg("%s", *argv); /* Avoid multibyte problems. */
retval = EXIT_FAILURE;
}
die_if_ferror_stdout();
}
fmt = header_fmt_str;
} while (*++argv);
fflush_stdout_and_exit(retval);
}
|
