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
|
/* vi: set sw=4 ts=4: */
/*
* Mini readlink implementation for busybox
*
* Copyright (C) 2000,2001 Matt Kraai <kraai@alumni.carnegiemellon.edu>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config READLINK
//config: bool "readlink (3.6 kb)"
//config: default y
//config: help
//config: This program reads a symbolic link and returns the name
//config: of the file it points to
//config:
//config:config FEATURE_READLINK_FOLLOW
//config: bool "Enable canonicalization by following all symlinks (-f)"
//config: default y
//config: depends on READLINK
//config: help
//config: Enable the readlink option (-f).
//applet:IF_READLINK(APPLET(readlink, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_READLINK) += readlink.o
//usage:#define readlink_trivial_usage
//usage: IF_FEATURE_READLINK_FOLLOW("[-fnv] ") "FILE"
//usage:#define readlink_full_usage "\n\n"
//usage: "Display the value of a symlink"
//usage: IF_FEATURE_READLINK_FOLLOW( "\n"
//usage: "\n -f Canonicalize by following all symlinks"
//usage: "\n -n Don't add newline"
//usage: "\n -v Verbose"
//usage: )
#include "libbb.h"
/*
* # readlink --version
* readlink (GNU coreutils) 6.10
* # readlink --help
* -f, --canonicalize
* canonicalize by following every symlink in
* every component of the given name recursively;
* all but the last component must exist
* -e, --canonicalize-existing
* canonicalize by following every symlink in
* every component of the given name recursively,
* all components must exist
* -m, --canonicalize-missing
* canonicalize by following every symlink in
* every component of the given name recursively,
* without requirements on components existence
* -n, --no-newline do not output the trailing newline
* -q, --quiet, -s, --silent suppress most error messages
* -v, --verbose report error messages
*
* bbox supports: -f (partially) -n -v (fully), -q -s (accepts but ignores)
* Note: we export the -f flag, but our -f behaves like coreutils' -e.
* Unfortunately, there isn't a C lib function we can leverage to get this
* behavior which means we'd have to implement the full stack ourselves :(.
*/
int readlink_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int readlink_main(int argc UNUSED_PARAM, char **argv)
{
char *buf;
char *fname;
IF_FEATURE_READLINK_FOLLOW(
unsigned opt;
/* We need exactly one non-option argument. */
opt_complementary = "=1";
opt = getopt32(argv, "fnvsq");
fname = argv[optind];
)
IF_NOT_FEATURE_READLINK_FOLLOW(
const unsigned opt = 0;
if (argc != 2) bb_show_usage();
fname = argv[1];
)
/* compat: coreutils readlink reports errors silently via exit code */
if (!(opt & 4)) /* not -v */
logmode = LOGMODE_NONE;
if (opt & 1) { /* -f */
buf = xmalloc_realpath(fname);
} else {
buf = xmalloc_readlink_or_warn(fname);
}
if (!buf)
return EXIT_FAILURE;
printf((opt & 2) ? "%s" : "%s\n", buf);
if (ENABLE_FEATURE_CLEAN_UP)
free(buf);
fflush_stdout_and_exit(EXIT_SUCCESS);
}
|
