1 /*
2  * Copyright (C) 2012 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 
29 typedef struct
30 {
31     void (**preinit_array)(void);
32     void (**init_array)(void);
33     void (**fini_array)(void);
34     void (**ctor_list)(void);
35 } structors_array_t;
36 
37 extern int main(int argc, char **argv, char **env);
38 
39 extern void __libc_init(
40   unsigned int *elfdata,
41   void (*onexit)(void),
42   int (*slingshot)(int, char**, char**),
43   structors_array_t const * const structors
44 );
45 
46 __attribute__ ((section (".preinit_array")))
47 void (*__PREINIT_ARRAY__)(void) = (void (*)(void)) -1;
48 
49 __attribute__ ((section (".init_array")))
50 void (*__INIT_ARRAY__)(void) = (void (*)(void)) -1;
51 
52 __attribute__ ((section (".fini_array")))
53 void (*__FINI_ARRAY__)(void) = (void (*)(void)) -1;
54 
55 __attribute__ ((section (".ctors")))
56 void (*__CTOR_LIST__)(void) = (void (*)(void)) -1;
57 
58 /* this is the small startup code that is first run when
59    any executable that is dynamically-linked with Bionic
60    runs.
61 
62    it's purpose is to call __libc_init with appropriate
63    arguments, which are:
64 
65     - the address of the raw data block setup by the Linux
66       kernel ELF loader
67 
68     - address of an "onexit" function, not used on any
69       platform supported by Bionic
70 
71     - address of the "main" function of the program.
72 
73     - address of the constructor list
74 */
75 
76 __attribute__((visibility("hidden")))
_start()77 void _start() {
78   structors_array_t array;
79   void *elfdata;
80 
81   array.preinit_array = &__PREINIT_ARRAY__;
82   array.init_array =    &__INIT_ARRAY__;
83   array.fini_array =    &__FINI_ARRAY__;
84   array.ctor_list =    &__CTOR_LIST__;
85 
86   elfdata = __builtin_frame_address(0) + sizeof(void *);
87   __libc_init(elfdata, (void *) 0, &main, &array);
88 }
89 
90 #include "__dso_handle.h"
91 #include "atexit.h"
92