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      1 /*
      2  * Copyright (C) 2015 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 #ifndef _PRIVATE_BIONIC_GLOBALS_H
     30 #define _PRIVATE_BIONIC_GLOBALS_H
     31 
     32 #include <stdatomic.h>
     33 #include <sys/cdefs.h>
     34 #include <link.h>
     35 #include <pthread.h>
     36 
     37 #include "private/bionic_allocator.h"
     38 #include "private/bionic_elf_tls.h"
     39 #include "private/bionic_fdsan.h"
     40 #include "private/bionic_malloc_dispatch.h"
     41 #include "private/bionic_vdso.h"
     42 #include "private/WriteProtected.h"
     43 
     44 struct libc_globals {
     45   vdso_entry vdso[VDSO_END];
     46   long setjmp_cookie;
     47 
     48   // In order to allow a complete switch between dispatch tables without
     49   // the need for copying each function by function in the structure,
     50   // use a single atomic pointer to switch.
     51   // The current_dispatch_table pointer can only ever be set to a complete
     52   // table. Any dispatch table that is pointed to by current_dispatch_table
     53   // cannot be modified after that. If the pointer changes in the future,
     54   // the old pointer must always stay valid.
     55   // The malloc_dispatch_table is modified by malloc debug, malloc hooks,
     56   // and heaprofd. Only one of these modes can be active at any given time.
     57   _Atomic(const MallocDispatch*) current_dispatch_table;
     58   // This pointer is only used by the allocation limit code when both a
     59   // limit is enabled and some other hook is enabled at the same time.
     60   _Atomic(const MallocDispatch*) default_dispatch_table;
     61   MallocDispatch malloc_dispatch_table;
     62 };
     63 
     64 __LIBC_HIDDEN__ extern WriteProtected<libc_globals> __libc_globals;
     65 
     66 struct abort_msg_t;
     67 
     68 // Globals shared between the dynamic linker and libc.so.
     69 struct libc_shared_globals {
     70   // Construct the shared globals using a constexpr constructor to ensure that
     71   // the object doesn't need dynamic initialization. The object is accessed
     72   // before the dynamic linker has relocated itself.
     73   constexpr libc_shared_globals() {}
     74 
     75   FdTable fd_table;
     76 
     77   // When the linker is invoked on a binary (e.g. `linker64 /system/bin/date`),
     78   // record the number of arguments passed to the linker itself rather than to
     79   // the program it's loading. Typically 0, sometimes 1.
     80   int initial_linker_arg_count = 0;
     81 
     82   ElfW(auxv_t)* auxv = nullptr;
     83 
     84   pthread_mutex_t abort_msg_lock = PTHREAD_MUTEX_INITIALIZER;
     85   abort_msg_t* abort_msg = nullptr;
     86 
     87   StaticTlsLayout static_tls_layout;
     88   TlsModules tls_modules;
     89   BionicAllocator tls_allocator;
     90 
     91   // Values passed from the linker to libc.so.
     92   const char* init_progname = nullptr;
     93   char** init_environ = nullptr;
     94 };
     95 
     96 __LIBC_HIDDEN__ libc_shared_globals* __libc_shared_globals();
     97 __LIBC_HIDDEN__ void __libc_init_fdsan();
     98 
     99 __LIBC_HIDDEN__ void __libc_init_malloc(libc_globals* globals);
    100 __LIBC_HIDDEN__ void __libc_init_setjmp_cookie(libc_globals* globals);
    101 __LIBC_HIDDEN__ void __libc_init_vdso(libc_globals* globals);
    102 
    103 #if defined(__i386__)
    104 __LIBC_HIDDEN__ extern void* __libc_sysinfo;
    105 __LIBC_HIDDEN__ void __libc_int0x80();
    106 __LIBC_HIDDEN__ void __libc_init_sysinfo();
    107 #endif
    108 
    109 #endif
    110