1 | /* Environment handling for dynamic loader. |
2 | Copyright (C) 1995-2017 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 <string.h> |
20 | #include <stdlib.h> |
21 | #include <unistd.h> |
22 | #include <ldsodefs.h> |
23 | |
24 | /* Walk through the environment of the process and return all entries |
25 | starting with `LD_'. */ |
26 | char * |
27 | internal_function |
28 | _dl_next_ld_env_entry (char ***position) |
29 | { |
30 | char **current = *position; |
31 | char *result = NULL; |
32 | |
33 | while (*current != NULL) |
34 | { |
35 | if (__builtin_expect ((*current)[0] == 'L', 0) |
36 | && (*current)[1] == 'D' && (*current)[2] == '_') |
37 | { |
38 | result = &(*current)[3]; |
39 | |
40 | /* Save current position for next visit. */ |
41 | *position = ++current; |
42 | |
43 | break; |
44 | } |
45 | |
46 | ++current; |
47 | } |
48 | |
49 | return result; |
50 | } |
51 | |
52 | |
53 | /* In ld.so __environ is not exported. */ |
54 | extern char **__environ attribute_hidden; |
55 | |
56 | int |
57 | unsetenv (const char *name) |
58 | { |
59 | char **ep; |
60 | |
61 | ep = __environ; |
62 | while (*ep != NULL) |
63 | { |
64 | size_t cnt = 0; |
65 | |
66 | while ((*ep)[cnt] == name[cnt] && name[cnt] != '\0') |
67 | ++cnt; |
68 | |
69 | if (name[cnt] == '\0' && (*ep)[cnt] == '=') |
70 | { |
71 | /* Found it. Remove this pointer by moving later ones to |
72 | the front. */ |
73 | char **dp = ep; |
74 | |
75 | do |
76 | dp[0] = dp[1]; |
77 | while (*dp++); |
78 | /* Continue the loop in case NAME appears again. */ |
79 | } |
80 | else |
81 | ++ep; |
82 | } |
83 | |
84 | return 0; |
85 | } |
86 | |