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      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 /* Call this function before anything else. 'vecs' must be the pointer
     32  * to the environment block in the ELF data block. The function returns
     33  * the start of the aux vectors after the env block.
     34  */
     35 extern unsigned*   linker_env_init(unsigned* vecs);
     36 
     37 /* Unset a given environment variable. In case the variable is defined
     38  * multiple times, unset all instances. This modifies the environment
     39  * block, so any pointer returned by linker_env_get() after this call
     40  * might become invalid */
     41 extern void        linker_env_unset(const char* name);
     42 
     43 
     44 /* Returns the value of environment variable 'name' if defined and not
     45  * empty, or NULL otherwise. Note that the returned pointer may become
     46  * invalid if linker_env_unset() or linker_env_secure() are called
     47  * after this function. */
     48 extern const char* linker_env_get(const char* name);
     49 
     50 /* Remove unsecure environment variables. This should be used when
     51  * running setuid programs. */
     52 extern void        linker_env_secure(void);
     53 
     54 #endif /* LINKER_ENVIRON_H */
     55