Prepare for radical source tree reorganization.zack/build-layout-experiment

All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).

1 files changed, 255 insertions, 0 deletions

diff --git a/REORG.TODO/sysdeps/nptl/fork.c b/REORG.TODO/sysdeps/nptl/fork.c
new file mode 100644
index 0000000000..4bb87e2331
--- /dev/null
+++ b/REORG.TODO/sysdeps/nptl/fork.c
@@ -0,0 +1,255 @@
+/* Copyright (C) 2002-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   The GNU C Library 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.
+
+   The GNU C Library 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 the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <assert.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sysdep.h>
+#include <libio/libioP.h>
+#include <tls.h>
+#include <hp-timing.h>
+#include <ldsodefs.h>
+#include <stdio-lock.h>
+#include <atomic.h>
+#include <nptl/pthreadP.h>
+#include <fork.h>
+#include <arch-fork.h>
+#include <futex-internal.h>
+#include <malloc/malloc-internal.h>
+
+static void
+fresetlockfiles (void)
+{
+  _IO_ITER i;
+
+  for (i = _IO_iter_begin(); i != _IO_iter_end(); i = _IO_iter_next(i))
+    if ((_IO_iter_file (i)->_flags & _IO_USER_LOCK) == 0)
+      _IO_lock_init (*((_IO_lock_t *) _IO_iter_file(i)->_lock));
+}
+
+
+pid_t
+__libc_fork (void)
+{
+  pid_t pid;
+  struct used_handler
+  {
+    struct fork_handler *handler;
+    struct used_handler *next;
+  } *allp = NULL;
+
+  /* Determine if we are running multiple threads.  We skip some fork
+     handlers in the single-thread case, to make fork safer to use in
+     signal handlers.  POSIX requires that fork is async-signal-safe,
+     but our current fork implementation is not.  */
+  bool multiple_threads = THREAD_GETMEM (THREAD_SELF, header.multiple_threads);
+
+  /* Run all the registered preparation handlers.  In reverse order.
+     While doing this we build up a list of all the entries.  */
+  struct fork_handler *runp;
+  while ((runp = __fork_handlers) != NULL)
+    {
+      /* Make sure we read from the current RUNP pointer.  */
+      atomic_full_barrier ();
+
+      unsigned int oldval = runp->refcntr;
+
+      if (oldval == 0)
+	/* This means some other thread removed the list just after
+	   the pointer has been loaded.  Try again.  Either the list
+	   is empty or we can retry it.  */
+	continue;
+
+      /* Bump the reference counter.  */
+      if (atomic_compare_and_exchange_bool_acq (&__fork_handlers->refcntr,
+						oldval + 1, oldval))
+	/* The value changed, try again.  */
+	continue;
+
+      /* We bumped the reference counter for the first entry in the
+	 list.  That means that none of the following entries will
+	 just go away.  The unloading code works in the order of the
+	 list.
+
+	 While executing the registered handlers we are building a
+	 list of all the entries so that we can go backward later on.  */
+      while (1)
+	{
+	  /* Execute the handler if there is one.  */
+	  if (runp->prepare_handler != NULL)
+	    runp->prepare_handler ();
+
+	  /* Create a new element for the list.  */
+	  struct used_handler *newp
+	    = (struct used_handler *) alloca (sizeof (*newp));
+	  newp->handler = runp;
+	  newp->next = allp;
+	  allp = newp;
+
+	  /* Advance to the next handler.  */
+	  runp = runp->next;
+	  if (runp == NULL)
+	    break;
+
+	  /* Bump the reference counter for the next entry.  */
+	  atomic_increment (&runp->refcntr);
+	}
+
+      /* We are done.  */
+      break;
+    }
+
+  /* If we are not running multiple threads, we do not have to
+     preserve lock state.  If fork runs from a signal handler, only
+     async-signal-safe functions can be used in the child.  These data
+     structures are only used by unsafe functions, so their state does
+     not matter if fork was called from a signal handler.  */
+  if (multiple_threads)
+    {
+      _IO_list_lock ();
+
+      /* Acquire malloc locks.  This needs to come last because fork
+	 handlers may use malloc, and the libio list lock has an
+	 indirect malloc dependency as well (via the getdelim
+	 function).  */
+      call_function_static_weak (__malloc_fork_lock_parent);
+    }
+
+#ifdef ARCH_FORK
+  pid = ARCH_FORK ();
+#else
+# error "ARCH_FORK must be defined so that the CLONE_SETTID flag is used"
+  pid = INLINE_SYSCALL (fork, 0);
+#endif
+
+
+  if (pid == 0)
+    {
+      struct pthread *self = THREAD_SELF;
+
+      /* See __pthread_once.  */
+      if (__fork_generation_pointer != NULL)
+	*__fork_generation_pointer += __PTHREAD_ONCE_FORK_GEN_INCR;
+
+#if HP_TIMING_AVAIL
+      /* The CPU clock of the thread and process have to be set to zero.  */
+      hp_timing_t now;
+      HP_TIMING_NOW (now);
+      THREAD_SETMEM (self, cpuclock_offset, now);
+      GL(dl_cpuclock_offset) = now;
+#endif
+
+#ifdef __NR_set_robust_list
+      /* Initialize the robust mutex list setting in the kernel which has
+	 been reset during the fork.  We do not check for errors because if
+	 it fails here, it must have failed at process startup as well and
+	 nobody could have used robust mutexes.
+	 Before we do that, we have to clear the list of robust mutexes
+	 because we do not inherit ownership of mutexes from the parent.
+	 We do not have to set self->robust_head.futex_offset since we do
+	 inherit the correct value from the parent.  We do not need to clear
+	 the pending operation because it must have been zero when fork was
+	 called.  */
+# ifdef __PTHREAD_MUTEX_HAVE_PREV
+      self->robust_prev = &self->robust_head;
+# endif
+      self->robust_head.list = &self->robust_head;
+# ifdef SHARED
+      if (__builtin_expect (__libc_pthread_functions_init, 0))
+	PTHFCT_CALL (ptr_set_robust, (self));
+# else
+      extern __typeof (__nptl_set_robust) __nptl_set_robust
+	__attribute__((weak));
+      if (__builtin_expect (__nptl_set_robust != NULL, 0))
+	__nptl_set_robust (self);
+# endif
+#endif
+
+      /* Reset the lock state in the multi-threaded case.  */
+      if (multiple_threads)
+	{
+	  /* Release malloc locks.  */
+	  call_function_static_weak (__malloc_fork_unlock_child);
+
+	  /* Reset the file list.  These are recursive mutexes.  */
+	  fresetlockfiles ();
+
+	  /* Reset locks in the I/O code.  */
+	  _IO_list_resetlock ();
+	}
+
+      /* Reset the lock the dynamic loader uses to protect its data.  */
+      __rtld_lock_initialize (GL(dl_load_lock));
+
+      /* Run the handlers registered for the child.  */
+      while (allp != NULL)
+	{
+	  if (allp->handler->child_handler != NULL)
+	    allp->handler->child_handler ();
+
+	  /* Note that we do not have to wake any possible waiter.
+	     This is the only thread in the new process.  The count
+	     may have been bumped up by other threads doing a fork.
+	     We reset it to 1, to avoid waiting for non-existing
+	     thread(s) to release the count.  */
+	  allp->handler->refcntr = 1;
+
+	  /* XXX We could at this point look through the object pool
+	     and mark all objects not on the __fork_handlers list as
+	     unused.  This is necessary in case the fork() happened
+	     while another thread called dlclose() and that call had
+	     to create a new list.  */
+
+	  allp = allp->next;
+	}
+
+      /* Initialize the fork lock.  */
+      __fork_lock = LLL_LOCK_INITIALIZER;
+    }
+  else
+    {
+      /* Release acquired locks in the multi-threaded case.  */
+      if (multiple_threads)
+	{
+	  /* Release malloc locks, parent process variant.  */
+	  call_function_static_weak (__malloc_fork_unlock_parent);
+
+	  /* We execute this even if the 'fork' call failed.  */
+	  _IO_list_unlock ();
+	}
+
+      /* Run the handlers registered for the parent.  */
+      while (allp != NULL)
+	{
+	  if (allp->handler->parent_handler != NULL)
+	    allp->handler->parent_handler ();
+
+	  if (atomic_decrement_and_test (&allp->handler->refcntr)
+	      && allp->handler->need_signal)
+	    futex_wake (&allp->handler->refcntr, 1, FUTEX_PRIVATE);
+
+	  allp = allp->next;
+	}
+    }
+
+  return pid;
+}
+weak_alias (__libc_fork, __fork)
+libc_hidden_def (__fork)
+weak_alias (__libc_fork, fork)