1/* This file is part of GNU paxutils
2   Copyright (C) 2005 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 2, 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.  */
26static size_t
27hash_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.  */
33static bool
34hash_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. */
43bool
44hash_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/* Return zero if TABLE contains a copy of STRING; otherwise, insert a
80   copy of STRING to TABLE and return 1.  */
81bool
82hash_string_insert (Hash_table **table, char const *string)
83{
84  return hash_string_insert_prefix (table, string, 0, NULL);
85}
86
87/* Return 1 if TABLE contains STRING.  */
88bool
89hash_string_lookup (Hash_table const *table, char const *string)
90{
91  return table && hash_lookup (table, string);
92}
93
94
95static Hash_table *prefix_table[2];
96
97/* Return true if file names of some members in the archive were stripped off
98   their leading components. We could have used
99        return prefix_table[0] || prefix_table[1]
100   but the following seems to be safer: */
101bool
102removed_prefixes_p (void)
103{
104  return (prefix_table[0] && hash_get_n_entries (prefix_table[0]) != 0)
105         || (prefix_table[1] && hash_get_n_entries (prefix_table[1]) != 0);
106}
107
108/* Return a safer suffix of FILE_NAME, or "." if it has no safer
109   suffix.  Check for fully specified file names and other atrocities.
110   Warn the user if we do not return NAME.  If LINK_TARGET is 1,
111   FILE_NAME is the target of a hard link, not a member name.
112   If ABSOLUTE_NAMES is 0, strip filesystem prefix from the file name. */
113
114char *
115safer_name_suffix (char const *file_name, bool link_target, bool absolute_names)
116{
117  char const *p;
118
119  if (absolute_names)
120    p = file_name;
121  else
122    {
123      /* Skip file system prefixes, leading file name components that contain
124	 "..", and leading slashes.  */
125
126      size_t prefix_len = FILE_SYSTEM_PREFIX_LEN (file_name);
127
128      for (p = file_name + prefix_len; *p; )
129	{
130          if (p[0] == '.' && p[1] == '.' && (ISSLASH (p[2]) || !p[2]))
131	    prefix_len = p + 2 - file_name;
132
133	  do
134	    {
135	      char c = *p++;
136	      if (ISSLASH (c))
137		break;
138	    }
139	  while (*p);
140	}
141
142      for (p = file_name + prefix_len; ISSLASH (*p); p++)
143	continue;
144      prefix_len = p - file_name;
145
146      if (prefix_len)
147	{
148         const char *prefix;
149         if (hash_string_insert_prefix (&prefix_table[link_target], file_name,
150                                        prefix_len, &prefix))
151	    {
152	      static char const *const diagnostic[] =
153	      {
154		N_("Removing leading `%s' from member names"),
155		N_("Removing leading `%s' from hard link targets")
156	      };
157	      WARN ((0, 0, _(diagnostic[link_target]), prefix));
158	    }
159	}
160    }
161
162  if (! *p)
163    {
164      if (p == file_name)
165	{
166	  static char const *const diagnostic[] =
167	  {
168	    N_("Substituting `.' for empty member name"),
169	    N_("Substituting `.' for empty hard link target")
170	  };
171	  WARN ((0, 0, "%s", _(diagnostic[link_target])));
172	}
173
174      p = ".";
175    }
176
177  return (char *) p;
178}
179