summaryrefslogtreecommitdiffhomepage
path: root/coreutils/cat.c
blob: 5f02233caa0c59e953941cf0022393a875fbf532 (plain)
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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/* vi: set sw=4 ts=4: */
/*
 * cat implementation for busybox
 *
 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
//config:config CAT
//config:	bool "cat (5.6 kb)"
//config:	default y
//config:	help
//config:	cat is used to concatenate files and print them to the standard
//config:	output. Enable this option if you wish to enable the 'cat' utility.
//config:
//config:config FEATURE_CATN
//config:	bool "Enable -n and -b options"
//config:	default y
//config:	depends on CAT
//config:	help
//config:	-n numbers all output lines while -b numbers nonempty output lines.
//config:
//config:config FEATURE_CATV
//config:	bool "cat -v[etA]"
//config:	default y
//config:	depends on CAT
//config:	help
//config:	Display nonprinting characters as escape sequences

//applet:IF_CAT(APPLET(cat, BB_DIR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_CAT) += cat.o

/* BB_AUDIT SUSv3 compliant */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/cat.html */

//usage:#if ENABLE_FEATURE_CATN || ENABLE_FEATURE_CATV
//usage:#define cat_trivial_usage
//usage:       "[-" IF_FEATURE_CATN("nb") IF_FEATURE_CATV("vteA") "] [FILE]..."
//usage:#else
//usage:#define cat_trivial_usage
//usage:       "[FILE]..."
//usage:#endif
//usage:#define cat_full_usage "\n\n"
//usage:       "Print FILEs to stdout\n"
//usage:	IF_FEATURE_CATN(
//usage:     "\n	-n	Number output lines"
//usage:     "\n	-b	Number nonempty lines"
//usage:	)
//usage:	IF_FEATURE_CATV(
//usage:     "\n	-v	Show nonprinting characters as ^x or M-x"
//usage:     "\n	-t	...and tabs as ^I"
//usage:     "\n	-e	...and end lines with $"
//usage:     "\n	-A	Same as -vte"
//usage:	)
/*
  Longopts not implemented yet:
      --number-nonblank    number nonempty output lines, overrides -n
      --number             number all output lines
      --show-nonprinting   use ^ and M- notation, except for LFD and TAB
      --show-all           equivalent to -vet
  Not implemented yet:
  -E, --show-ends          display $ at end of each line (-e sans -v)
  -T, --show-tabs          display TAB characters as ^I (-t sans -v)
  -s, --squeeze-blank      suppress repeated empty output lines
*/
//usage:
//usage:#define cat_example_usage
//usage:       "$ cat /proc/uptime\n"
//usage:       "110716.72 17.67"

#include "libbb.h"
#include "common_bufsiz.h"

#if ENABLE_FEATURE_CATV
/*
 * cat -v implementation for busybox
 *
 * Copyright (C) 2006 Rob Landley <rob@landley.net>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
/* Rob had "cat -v" implemented as a separate applet, catv.
 * See "cat -v considered harmful" at
 * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz
 * From USENIX Summer Conference Proceedings, 1983
 * """
 * The talk reviews reasons for UNIX's popularity and shows, using UCB cat
 * as a primary example, how UNIX has grown fat. cat isn't for printing
 * files with line numbers, it isn't for compressing multiple blank lines,
 * it's not for looking at non-printing ASCII characters, it's for
 * concatenating files.
 * We are reminded that ls isn't the place for code to break a single column
 * into multiple ones, and that mailnews shouldn't have its own more
 * processing or joke encryption code.
 * """
 *
 * I agree with the argument. Unfortunately, this ship has sailed (1983...).
 * There are dozens of Linux distros and each of them has "cat" which supports -v.
 * It's unrealistic for us to "reeducate" them to use our, incompatible way
 * to achieve "cat -v" effect. The actual effect would be "users pissed off
 * by gratuitous incompatibility".
 */
#define CAT_OPT_e (1<<0)
#define CAT_OPT_t (1<<1)
#define CAT_OPT_v (1<<2)
/* -A occupies bit (1<<3) */
#define CAT_OPT_n ((1<<4) * ENABLE_FEATURE_CATN)
#define CAT_OPT_b ((1<<5) * ENABLE_FEATURE_CATN)
static int catv(unsigned opts, char **argv)
{
	int retval = EXIT_SUCCESS;
	int fd;
#if ENABLE_FEATURE_CATN
	unsigned lineno = 0;
	unsigned eol_char = (opts & (CAT_OPT_n|CAT_OPT_b)) ? '\n' : 0x100;
	unsigned skip_num_on = (opts & CAT_OPT_b) ? '\n' : 0x100;
	bool eol_seen = 1;
#endif

	BUILD_BUG_ON(CAT_OPT_e != VISIBLE_ENDLINE);
	BUILD_BUG_ON(CAT_OPT_t != VISIBLE_SHOW_TABS);
#if 0 /* These consts match, we can just pass "opts" to visible() */
	if (opts & CAT_OPT_e)
		flags |= VISIBLE_ENDLINE;
	if (opts & CAT_OPT_t)
		flags |= VISIBLE_SHOW_TABS;
#endif

#define read_buf bb_common_bufsiz1
	setup_common_bufsiz();
	do {
		fd = open_or_warn_stdin(*argv);
		if (fd < 0) {
			retval = EXIT_FAILURE;
			continue;
		}
		for (;;) {
			int i, res;

			res = read(fd, read_buf, COMMON_BUFSIZE);
			if (res < 0)
				retval = EXIT_FAILURE;
			if (res <= 0)
				break;
			for (i = 0; i < res; i++) {
				unsigned char c = read_buf[i];
				char buf[sizeof("M-^c")];
#if ENABLE_FEATURE_CATN
				if (eol_seen && c != skip_num_on)
					printf("%6u  ", ++lineno);
				eol_seen = (c == eol_char);
#endif
				visible(c, buf, opts);
				fputs(buf, stdout);
			}
		}
		if (ENABLE_FEATURE_CLEAN_UP && fd)
			close(fd);
	} while (*++argv);

	fflush_stdout_and_exit(retval);
}
#undef CAT_OPT_n
#undef CAT_OPT_b
#endif

int cat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cat_main(int argc UNUSED_PARAM, char **argv)
{
#if ENABLE_FEATURE_CATV || ENABLE_FEATURE_CATN
	unsigned opts;

	opts =
#endif
	getopt32(argv, IF_FEATURE_CATV("^")
		/* -u is ignored ("unbuffered") */
		IF_FEATURE_CATV("etvA")IF_FEATURE_CATN("nb")"u"
		IF_FEATURE_CATV("\0" "Aetv" /* -A == -vet */)
	);
	argv += optind;

	/* Read from stdin if there's nothing else to do. */
	if (!argv[0])
		*--argv = (char*)"-";

#if ENABLE_FEATURE_CATV
	if (opts & 7)
		return catv(opts, argv);
	opts >>= 4;
#endif

#if ENABLE_FEATURE_CATN
# define CAT_OPT_n (1<<0)
# define CAT_OPT_b (1<<1)
	if (opts & (CAT_OPT_n|CAT_OPT_b)) { /* -n or -b */
		struct number_state ns;

		ns.width = 6;
		ns.start = 1;
		ns.inc = 1;
		ns.sep = "\t";
		ns.empty_str = "\n";
		ns.all = !(opts & CAT_OPT_b); /* -n without -b */
		ns.nonempty = (opts & CAT_OPT_b); /* -b (with or without -n) */
		do {
			print_numbered_lines(&ns, *argv);
		} while (*++argv);
		fflush_stdout_and_exit(EXIT_SUCCESS);
	}
	/*opts >>= 2;*/
#endif

	return bb_cat(argv);
}