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      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 
     42 extern unsigned __get_sp(void);
     43 extern pid_t    gettid(void);
     44 
     45 char*  __progname;
     46 char **environ;
     47 
     48 /* from asm/page.h */
     49 unsigned int __page_size = PAGE_SIZE;
     50 unsigned int __page_shift = PAGE_SHIFT;
     51 
     52 
     53 int __system_properties_init(void);
     54 
     55 void __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 main 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  */
     95 void __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