1/* Handling of dynamic sring tokens.
2 Copyright (C) 1999-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include "trusted-dirs.h"
20
21/* Determine the number of DST elements in the name. Only if IS_PATH is
22 nonzero paths are recognized (i.e., multiple, ':' separated filenames). */
23#define DL_DST_COUNT(name) \
24 ({ \
25 size_t __cnt = 0; \
26 const char *__sf = strchr (name, '$'); \
27 \
28 if (__glibc_unlikely (__sf != NULL)) \
29 __cnt = _dl_dst_count (__sf); \
30 \
31 __cnt; })
32
33
34#ifdef SHARED
35# define IS_RTLD(l) (l) == &GL(dl_rtld_map)
36#else
37# define IS_RTLD(l) 0
38#endif
39/* Guess from the number of DSTs the length of the result string. */
40#define DL_DST_REQUIRED(l, name, len, cnt) \
41 ({ \
42 size_t __len = (len); \
43 size_t __cnt = (cnt); \
44 \
45 if (__cnt > 0) \
46 { \
47 size_t dst_len; \
48 /* Now we make a guess how many extra characters on top of the \
49 length of S we need to represent the result. We know that \
50 we have CNT replacements. Each at most can use \
51 MAX (MAX (strlen (ORIGIN), strlen (_dl_platform)), \
52 strlen (DL_DST_LIB)) \
53 minus 4 (which is the length of "$LIB"). \
54 \
55 First get the origin string if it is not available yet. \
56 This can only happen for the map of the executable or, when \
57 auditing, in ld.so. */ \
58 if ((l)->l_origin == NULL) \
59 { \
60 assert ((l)->l_name[0] == '\0' || IS_RTLD (l)); \
61 (l)->l_origin = _dl_get_origin (); \
62 dst_len = ((l)->l_origin && (l)->l_origin != (char *) -1 \
63 ? strlen ((l)->l_origin) : 0); \
64 } \
65 else \
66 dst_len = (l)->l_origin == (char *) -1 \
67 ? 0 : strlen ((l)->l_origin); \
68 dst_len = MAX (MAX (dst_len, GLRO(dl_platformlen)), \
69 strlen (DL_DST_LIB)); \
70 if (dst_len > 4) \
71 __len += __cnt * (dst_len - 4); \
72 } \
73 \
74 __len; })
75