linker_environ.h revision 4688279db5dcc4004941e7f133c4a1c3617d842c 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28#ifndef LINKER_ENVIRON_H
29#define LINKER_ENVIRON_H
30
31#ifdef __cplusplus
32extern "C" {
33#endif
34
35/* Call this function before anything else. 'vecs' must be the pointer
36 * to the environment block in the ELF data block. The function returns
37 * the start of the aux vectors after the env block.
38 */
39extern unsigned*   linker_env_init(unsigned* vecs);
40
41/* Unset a given environment variable. In case the variable is defined
42 * multiple times, unset all instances. This modifies the environment
43 * block, so any pointer returned by linker_env_get() after this call
44 * might become invalid */
45extern void        linker_env_unset(const char* name);
46
47
48/* Returns the value of environment variable 'name' if defined and not
49 * empty, or NULL otherwise. Note that the returned pointer may become
50 * invalid if linker_env_unset() or linker_env_secure() are called
51 * after this function. */
52extern const char* linker_env_get(const char* name);
53
54/* Remove insecure environment variables. This should be used when
55 * running setuid programs. */
56extern void        linker_env_secure(void);
57
58#ifdef __cplusplus
59};
60#endif
61
62#endif /* LINKER_ENVIRON_H */
63