| 1 | /* Return the internal lock used by setlocale_null_r. |
| 2 | Copyright (C) 2019-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | This program is free software: you can redistribute it and/or modify |
| 5 | it under the terms of the GNU General Public License as published by |
| 6 | the Free Software Foundation; either version 3 of the License, or |
| 7 | (at your option) any later version. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | /* Written by Bruno Haible <bruno@clisp.org>, 2019. */ |
| 18 | |
| 19 | #include <config.h> |
| 20 | |
| 21 | /* When it is known that the gl_get_setlocale_null_lock function is defined |
| 22 | by a dependency library, it should not be defined here. */ |
| 23 | #if OMIT_SETLOCALE_LOCK |
| 24 | |
| 25 | /* This declaration is solely to ensure that after preprocessing |
| 26 | this file is never empty. */ |
| 27 | typedef int dummy; |
| 28 | |
| 29 | #else |
| 30 | |
| 31 | /* This file defines the internal lock used by setlocale_null_r. |
| 32 | It is a separate compilation unit, so that only one copy of it is |
| 33 | present when linking statically. */ |
| 34 | |
| 35 | /* Prohibit renaming this symbol. */ |
| 36 | # undef gl_get_setlocale_null_lock |
| 37 | |
| 38 | /* Macro for exporting a symbol (function, not variable) defined in this file, |
| 39 | when compiled into a shared library. */ |
| 40 | # ifndef DLL_EXPORTED |
| 41 | # if HAVE_VISIBILITY |
| 42 | /* Override the effect of the compiler option '-fvisibility=hidden'. */ |
| 43 | # define DLL_EXPORTED __attribute__((__visibility__("default"))) |
| 44 | # elif defined _WIN32 || defined __CYGWIN__ |
| 45 | # define DLL_EXPORTED __declspec(dllexport) |
| 46 | # else |
| 47 | # define DLL_EXPORTED |
| 48 | # endif |
| 49 | # endif |
| 50 | |
| 51 | # if defined _WIN32 && !defined __CYGWIN__ |
| 52 | |
| 53 | # define WIN32_LEAN_AND_MEAN /* avoid including junk */ |
| 54 | # include <windows.h> |
| 55 | |
| 56 | # include "windows-initguard.h" |
| 57 | |
| 58 | /* The return type is a 'CRITICAL_SECTION *', not a 'glwthread_mutex_t *', |
| 59 | because the latter is not guaranteed to be a stable ABI in the future. */ |
| 60 | |
| 61 | /* Make sure the function gets exported from DLLs. */ |
| 62 | DLL_EXPORTED CRITICAL_SECTION *gl_get_setlocale_null_lock (void); |
| 63 | |
| 64 | static glwthread_initguard_t guard = GLWTHREAD_INITGUARD_INIT; |
| 65 | static CRITICAL_SECTION lock; |
| 66 | |
| 67 | /* Returns the internal lock used by setlocale_null_r. */ |
| 68 | CRITICAL_SECTION * |
| 69 | gl_get_setlocale_null_lock (void) |
| 70 | { |
| 71 | if (!guard.done) |
| 72 | { |
| 73 | if (InterlockedIncrement (&guard.started) == 0) |
| 74 | { |
| 75 | /* This thread is the first one to need the lock. Initialize it. */ |
| 76 | InitializeCriticalSection (&lock); |
| 77 | guard.done = 1; |
| 78 | } |
| 79 | else |
| 80 | { |
| 81 | /* Don't let guard.started grow and wrap around. */ |
| 82 | InterlockedDecrement (&guard.started); |
| 83 | /* Yield the CPU while waiting for another thread to finish |
| 84 | initializing this mutex. */ |
| 85 | while (!guard.done) |
| 86 | Sleep (0); |
| 87 | } |
| 88 | } |
| 89 | return &lock; |
| 90 | } |
| 91 | |
| 92 | # elif HAVE_PTHREAD_API |
| 93 | |
| 94 | # include <pthread.h> |
| 95 | |
| 96 | static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; |
| 97 | |
| 98 | /* Make sure the function gets exported from shared libraries. */ |
| 99 | DLL_EXPORTED pthread_mutex_t *gl_get_setlocale_null_lock (void); |
| 100 | |
| 101 | /* Returns the internal lock used by setlocale_null_r. */ |
| 102 | pthread_mutex_t * |
| 103 | gl_get_setlocale_null_lock (void) |
| 104 | { |
| 105 | return &mutex; |
| 106 | } |
| 107 | |
| 108 | # elif HAVE_THREADS_H |
| 109 | |
| 110 | # include <threads.h> |
| 111 | # include <stdlib.h> |
| 112 | |
| 113 | static int volatile init_needed = 1; |
| 114 | static once_flag init_once = ONCE_FLAG_INIT; |
| 115 | static mtx_t mutex; |
| 116 | |
| 117 | static void |
| 118 | atomic_init (void) |
| 119 | { |
| 120 | if (mtx_init (&mutex, mtx_plain) != thrd_success) |
| 121 | abort (); |
| 122 | init_needed = 0; |
| 123 | } |
| 124 | |
| 125 | /* Make sure the function gets exported from shared libraries. */ |
| 126 | DLL_EXPORTED mtx_t *gl_get_setlocale_null_lock (void); |
| 127 | |
| 128 | /* Returns the internal lock used by setlocale_null_r. */ |
| 129 | mtx_t * |
| 130 | gl_get_setlocale_null_lock (void) |
| 131 | { |
| 132 | if (init_needed) |
| 133 | call_once (&init_once, atomic_init); |
| 134 | return &mutex; |
| 135 | } |
| 136 | |
| 137 | # endif |
| 138 | |
| 139 | # if (defined _WIN32 || defined __CYGWIN__) && !defined _MSC_VER |
| 140 | /* Make sure the '__declspec(dllimport)' in setlocale_null.c does not cause |
| 141 | a link failure when no DLLs are involved. */ |
| 142 | # if defined _WIN64 || defined _LP64 |
| 143 | # define IMP(x) __imp_##x |
| 144 | # else |
| 145 | # define IMP(x) _imp__##x |
| 146 | # endif |
| 147 | void * IMP(gl_get_setlocale_null_lock) = &gl_get_setlocale_null_lock; |
| 148 | # endif |
| 149 | |
| 150 | #endif |