libc_init_common.c revision 1df986c21ee52c6756846b4a5e45cb316f772112 
1/*
2 * Copyright (C) 2008 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#include <stddef.h>
30#include <stdio.h>
31#include <stdlib.h>
32#include <stdint.h>
33#include <elf.h>
34#include <asm/page.h>
35#include "pthread_internal.h"
36#include "atexit.h"
37#include "libc_init_common.h"
38
39#include <bionic_tls.h>
40#include <errno.h>
41
42extern unsigned __get_sp(void);
43extern pid_t    gettid(void);
44
45char*  __progname;
46char **environ;
47
48/* from asm/page.h */
49unsigned int __page_size = PAGE_SIZE;
50unsigned int __page_shift = PAGE_SHIFT;
51
52
53int __system_properties_init(void);
54
55void __libc_init_common(uintptr_t *elfdata)
56{
57    int     argc = *elfdata;
58    char**  argv = (char**)(elfdata + 1);
59    char**  envp = argv + argc + 1;
60
61    pthread_attr_t             thread_attr;
62    static pthread_internal_t  thread;
63    static void*               tls_area[BIONIC_TLS_SLOTS];
64
65    /* setup pthread runtime and maint thread descriptor */
66    unsigned stacktop = (__get_sp() & ~(PAGE_SIZE - 1)) + PAGE_SIZE;
67    unsigned stacksize = 128 * 1024;
68    unsigned stackbottom = stacktop - stacksize;
69
70    pthread_attr_init(&thread_attr);
71    pthread_attr_setstack(&thread_attr, (void*)stackbottom, stacksize);
72    _init_thread(&thread, gettid(), &thread_attr, (void*)stackbottom);
73    __init_tls(tls_area, &thread);
74
75    /* clear errno - requires TLS area */
76    errno = 0;
77
78    /* set program name */
79    __progname = argv[0] ? argv[0] : "<unknown>";
80
81    /* setup environment pointer */
82    environ = envp;
83
84    /* setup system properties - requires environment */
85    __system_properties_init();
86}
87
88/* This function will be called during normal program termination
89 * to run the destructors that are listed in the .fini_array section
90 * of the executable, if any.
91 *
92 * 'fini_array' points to a list of function addresses. The first
93 * entry in the list has value -1, the last one has value 0.
94 */
95void __libc_fini(void* array)
96{
97    int count;
98    void** fini_array = array;
99    const size_t  minus1 = ~(size_t)0; /* ensure proper sign extension */
100
101    /* Sanity check - first entry must be -1 */
102    if (array == NULL || (size_t)fini_array[0] != minus1) {
103        return;
104    }
105
106    /* skip over it */
107    fini_array += 1;
108
109    /* Count the number of destructors. */
110    for (count = 0; fini_array[count] != NULL; count++);
111
112    /* Now call each destructor in reverse order. */
113    while (count > 0) {
114        void (*func)() = (void (*)) fini_array[--count];
115
116        /* Sanity check, any -1 in the list is ignored */
117        if ((size_t)func == minus1)
118            continue;
119
120        func();
121    }
122}
123