1/* Environment handling for dynamic loader.
2 Copyright (C) 1995-2023 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 <https://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_'. */
26char *
27_dl_next_ld_env_entry (char ***position)
28{
29 char **current = *position;
30 char *result = NULL;
31
32 while (*current != NULL)
33 {
34 if (__builtin_expect ((*current)[0] == 'L', 0)
35 && (*current)[1] == 'D' && (*current)[2] == '_')
36 {
37 result = &(*current)[3];
38
39 /* Save current position for next visit. */
40 *position = ++current;
41
42 break;
43 }
44
45 ++current;
46 }
47
48 return result;
49}
50
51
52/* In ld.so __environ is not exported. */
53extern char **__environ attribute_hidden;
54
55int
56unsetenv (const char *name)
57{
58 char **ep;
59
60 ep = __environ;
61 while (*ep != NULL)
62 {
63 size_t cnt = 0;
64
65 while ((*ep)[cnt] == name[cnt] && name[cnt] != '\0')
66 ++cnt;
67
68 if (name[cnt] == '\0' && (*ep)[cnt] == '=')
69 {
70 /* Found it. Remove this pointer by moving later ones to
71 the front. */
72 char **dp = ep;
73
74 do
75 dp[0] = dp[1];
76 while (*dp++);
77 /* Continue the loop in case NAME appears again. */
78 }
79 else
80 ++ep;
81 }
82
83 return 0;
84}
85