1 files changed, 125 insertions, 0 deletions
diff --git a/lib/mbtowc-lock.h b/lib/mbtowc-lock.h
new file mode 100644
index 00000000..ecfd44e8
--- /dev/null
+++ b/lib/mbtowc-lock.h
@@ -0,0 +1,125 @@
+/* Use the internal lock used by mbrtowc and mbrtoc32.
+   Copyright (C) 2019-2022 Free Software Foundation, Inc.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2019-2020.  */
+
+/* Use a lock, so that no two threads can invoke mbtowc at the same time.  */
+
+static inline int
+mbtowc_unlocked (wchar_t *pwc, const char *p, size_t m)
+{
+  /* Put the hidden internal state of mbtowc into its initial state.
+     This is needed at least with glibc, uClibc, and MSVC CRT.
+     See <https://sourceware.org/bugzilla/show_bug.cgi?id=9674>.  */
+  mbtowc (NULL, NULL, 0);
+
+  return mbtowc (pwc, p, m);
+}
+
+/* Prohibit renaming this symbol.  */
+#undef gl_get_mbtowc_lock
+
+#if GNULIB_MBRTOWC_SINGLE_THREAD
+
+/* All uses of this function are in a single thread.  No locking needed.  */
+
+static int
+mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
+{
+  return mbtowc_unlocked (pwc, p, m);
+}
+
+#elif defined _WIN32 && !defined __CYGWIN__
+
+extern __declspec(dllimport) CRITICAL_SECTION *gl_get_mbtowc_lock (void);
+
+static int
+mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
+{
+  CRITICAL_SECTION *lock = gl_get_mbtowc_lock ();
+  int ret;
+
+  EnterCriticalSection (lock);
+  ret = mbtowc_unlocked (pwc, p, m);
+  LeaveCriticalSection (lock);
+
+  return ret;
+}
+
+#elif HAVE_PTHREAD_API /* AIX, IRIX, Cygwin */
+
+extern
+# if defined _WIN32 || defined __CYGWIN__
+  __declspec(dllimport)
+# endif
+  pthread_mutex_t *gl_get_mbtowc_lock (void);
+
+# if HAVE_WEAK_SYMBOLS /* IRIX */
+
+   /* Avoid the need to link with '-lpthread'.  */
+#  pragma weak pthread_mutex_lock
+#  pragma weak pthread_mutex_unlock
+
+   /* Determine whether libpthread is in use.  */
+#  pragma weak pthread_mutexattr_gettype
+   /* See the comments in lock.h.  */
+#  define pthread_in_use() \
+     (pthread_mutexattr_gettype != NULL || c11_threads_in_use ())
+
+# else
+#  define pthread_in_use() 1
+# endif
+
+static int
+mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
+{
+  if (pthread_in_use())
+    {
+      pthread_mutex_t *lock = gl_get_mbtowc_lock ();
+      int ret;
+
+      if (pthread_mutex_lock (lock))
+        abort ();
+      ret = mbtowc_unlocked (pwc, p, m);
+      if (pthread_mutex_unlock (lock))
+        abort ();
+
+      return ret;
+    }
+  else
+    return mbtowc_unlocked (pwc, p, m);
+}
+
+#elif HAVE_THREADS_H
+
+extern mtx_t *gl_get_mbtowc_lock (void);
+
+static int
+mbtowc_with_lock (wchar_t *pwc, const char *p, size_t m)
+{
+  mtx_t *lock = gl_get_mbtowc_lock ();
+  int ret;
+
+  if (mtx_lock (lock) != thrd_success)
+    abort ();
+  ret = mbtowc_unlocked (pwc, p, m);
+  if (mtx_unlock (lock) != thrd_success)
+    abort ();
+
+  return ret;
+}
+
+#endif