1 /* This file is part of GNU paxutils
2 Copyright (C) 2005, 2007, 2010, 2023 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 3, or (at your option) any later
7 version.
8
9 This program is distributed in the hope that it will be useful, but
10 WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
12 Public License for more details.
13
14 You should have received a copy of the GNU General Public License along
15 with this program; if not, write to the Free Software Foundation, Inc.,
16 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
17
18 #include <system.h>
19 #include <hash.h>
20 #include <paxlib.h>
21
22
23 /* Hash tables of strings. */
24
25 /* Calculate the hash of a string. */
26 static size_t
27 hash_string_hasher (void const *name, size_t n_buckets)
28 {
29 return hash_string (name, n_buckets);
30 }
31
32 /* Compare two strings for equality. */
33 static bool
34 hash_string_compare (void const *name1, void const *name2)
35 {
36 return strcmp (name1, name2) == 0;
37 }
38
39 /* Return zero if TABLE contains a LEN-character long prefix of STRING,
40 otherwise, insert a newly allocated copy of this prefix to TABLE and
41 return 1. If RETURN_PREFIX is not NULL, point it to the allocated
42 copy. */
43 static bool
44 hash_string_insert_prefix (Hash_table **table, char const *string, size_t len,
45 const char **return_prefix)
46 {
47 Hash_table *t = *table;
48 char *s;
49 char *e;
50
51 if (len)
52 {
53 s = xmalloc (len + 1);
54 memcpy (s, string, len);
55 s[len] = 0;
56 }
57 else
58 s = xstrdup (string);
59
60 if (! ((t
61 || (*table = t = hash_initialize (0, 0, hash_string_hasher,
62 hash_string_compare, 0)))
63 && (e = hash_insert (t, s))))
64 xalloc_die ();
65
66 if (e == s)
67 {
68 if (return_prefix)
69 *return_prefix = s;
70 return 1;
71 }
72 else
73 {
74 free (s);
75 return 0;
76 }
77 }
78
79
80 static Hash_table *prefix_table[2];
81
82 /* Return true if file names of some members in the archive were stripped off
83 their leading components. We could have used
84 return prefix_table[0] || prefix_table[1]
85 but the following seems to be safer: */
86 bool
87 removed_prefixes_p (void)
88 {
89 return (prefix_table[0] && hash_get_n_entries (prefix_table[0]) != 0)
90 || (prefix_table[1] && hash_get_n_entries (prefix_table[1]) != 0);
91 }
92
93 /* Return a safer suffix of FILE_NAME, or "." if it has no safer
94 suffix. Check for fully specified file names and other atrocities.
95 Warn the user if we do not return NAME. If LINK_TARGET is 1,
96 FILE_NAME is the target of a hard link, not a member name.
97 If ABSOLUTE_NAMES is 0, strip filesystem prefix from the file name. */
98
99 char *
100 safer_name_suffix (char const *file_name, bool link_target,
101 bool absolute_names)
102 {
103 char const *p;
104
105 if (absolute_names)
106 p = file_name;
107 else
108 {
109 /* Skip file system prefixes, leading file name components that contain
110 "..", and leading slashes. */
111
112 size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (file_name);
113
114 for (p = file_name + prefix_len; *p; )
115 {
116 if (p[0] == '.' && p[1] == '.' && (ISSLASH (p[2]) || !p[2]))
117 prefix_len = p + 2 - file_name;
118
119 do
120 {
121 char c = *p++;
122 if (ISSLASH (c))
123 break;
124 }
125 while (*p);
126 }
127
128 for (p = file_name + prefix_len; ISSLASH (*p); p++)
129 continue;
130 prefix_len = p - file_name;
131
132 if (prefix_len)
133 {
134 const char *prefix;
135 if (hash_string_insert_prefix (&prefix_table[link_target], file_name,
136 prefix_len, &prefix))
137 {
138 static char const *const diagnostic[] =
139 {
140 N_("Removing leading `%s' from member names"),
141 N_("Removing leading `%s' from hard link targets")
142 };
143 WARN ((0, 0, _(diagnostic[link_target]), prefix));
144 }
145 }
146 }
147
148 if (! *p)
149 {
150 if (p == file_name)
151 {
152 static char const *const diagnostic[] =
153 {
154 N_("Substituting `.' for empty member name"),
155 N_("Substituting `.' for empty hard link target")
156 };
157 WARN ((0, 0, "%s", _(diagnostic[link_target])));
158 }
159
160 p = ".";
161 }
162
163 return (char *) p;
164 }