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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 #ifndef __BIONIC_PRIVATE_BIONIC_TLS_H_
     30 #define __BIONIC_PRIVATE_BIONIC_TLS_H_
     31 
     32 #include <locale.h>
     33 #include <mntent.h>
     34 #include <stdio.h>
     35 #include <sys/cdefs.h>
     36 #include <sys/param.h>
     37 
     38 #include "bionic_macros.h"
     39 #include "__get_tls.h"
     40 #include "grp_pwd.h"
     41 
     42 __BEGIN_DECLS
     43 
     44 /** WARNING WARNING WARNING
     45  **
     46  ** This header file is *NOT* part of the public Bionic ABI/API
     47  ** and should not be used/included by user-serviceable parts of
     48  ** the system (e.g. applications).
     49  **
     50  ** It is only provided here for the benefit of the system dynamic
     51  ** linker and the OpenGL sub-system (which needs to access the
     52  ** pre-allocated slot directly for performance reason).
     53  **/
     54 
     55 // Well-known TLS slots. What data goes in which slot is arbitrary unless otherwise noted.
     56 enum {
     57   TLS_SLOT_SELF = 0, // The kernel requires this specific slot for x86.
     58   TLS_SLOT_THREAD_ID,
     59   TLS_SLOT_ERRNO,
     60 
     61   // These two aren't used by bionic itself, but allow the graphics code to
     62   // access TLS directly rather than using the pthread API.
     63   TLS_SLOT_OPENGL_API = 3,
     64   TLS_SLOT_OPENGL = 4,
     65 
     66   // This slot is only used to pass information from the dynamic linker to
     67   // libc.so when the C library is loaded in to memory. The C runtime init
     68   // function will then clear it. Since its use is extremely temporary,
     69   // we reuse an existing location that isn't needed during libc startup.
     70   TLS_SLOT_BIONIC_PREINIT = TLS_SLOT_OPENGL_API,
     71 
     72   TLS_SLOT_STACK_GUARD = 5, // GCC requires this specific slot for x86.
     73   TLS_SLOT_DLERROR,
     74 
     75   // Fast storage for Thread::Current() in ART.
     76   TLS_SLOT_ART_THREAD_SELF,
     77 
     78   // Lets TSAN avoid using pthread_getspecific for finding the current thread
     79   // state.
     80   TLS_SLOT_TSAN,
     81 
     82   BIONIC_TLS_SLOTS // Must come last!
     83 };
     84 
     85 // ~3 pages.
     86 struct bionic_tls {
     87   locale_t locale;
     88 
     89   char basename_buf[MAXPATHLEN];
     90   char dirname_buf[MAXPATHLEN];
     91 
     92   mntent mntent_buf;
     93   char mntent_strings[BUFSIZ];
     94 
     95   char ptsname_buf[32];
     96   char ttyname_buf[64];
     97 
     98   char strerror_buf[NL_TEXTMAX];
     99   char strsignal_buf[NL_TEXTMAX];
    100 
    101   group_state_t group;
    102   passwd_state_t passwd;
    103 };
    104 
    105 #define BIONIC_TLS_SIZE (__BIONIC_ALIGN(sizeof(bionic_tls), PAGE_SIZE))
    106 
    107 /*
    108  * Bionic uses some pthread keys internally. All pthread keys used internally
    109  * should be created in constructors, except for keys that may be used in or
    110  * before constructors.
    111  *
    112  * We need to manually maintain the count of pthread keys used internally, but
    113  * pthread_test should fail if we forget.
    114  *
    115  * These are the pthread keys currently used internally by libc:
    116  *  _res_key               libc (constructor in BSD code)
    117  */
    118 
    119 #define LIBC_PTHREAD_KEY_RESERVED_COUNT 1
    120 
    121 /* Internally, jemalloc uses a single key for per thread data. */
    122 #define JEMALLOC_PTHREAD_KEY_RESERVED_COUNT 1
    123 #define BIONIC_PTHREAD_KEY_RESERVED_COUNT (LIBC_PTHREAD_KEY_RESERVED_COUNT + JEMALLOC_PTHREAD_KEY_RESERVED_COUNT)
    124 
    125 /*
    126  * Maximum number of pthread keys allocated.
    127  * This includes pthread keys used internally and externally.
    128  */
    129 #define BIONIC_PTHREAD_KEY_COUNT (BIONIC_PTHREAD_KEY_RESERVED_COUNT + PTHREAD_KEYS_MAX)
    130 
    131 __END_DECLS
    132 
    133 #if defined(__cplusplus)
    134 class KernelArgumentBlock;
    135 extern void __libc_init_main_thread(KernelArgumentBlock&);
    136 #endif
    137 
    138 #endif /* __BIONIC_PRIVATE_BIONIC_TLS_H_ */
    139