Get rid of nptl/sysdeps/ entirely!

1 files changed, 238 insertions, 0 deletions

diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c
new file mode 100644
index 0000000000..70201a294c
--- /dev/null
+++ b/sysdeps/nptl/fork.c
@@ -0,0 +1,238 @@
+/* Copyright (C) 2002-2014 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 <bits/stdio-lock.h>
+#include <atomic.h>
+#include <pthreadP.h>
+#include <fork.h>
+#include <arch-fork.h>
+
+
+unsigned long int *__fork_generation_pointer;
+
+
+
+/* The single linked list of all currently registered fork handlers.  */
+struct fork_handler *__fork_handlers;
+
+
+static void
+fresetlockfiles (void)
+{
+  _IO_ITER i;
+
+  for (i = _IO_iter_begin(); i != _IO_iter_end(); i = _IO_iter_next(i))
+    _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;
+
+  /* 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;
+    }
+
+  _IO_list_lock ();
+
+#ifndef NDEBUG
+  pid_t ppid = THREAD_GETMEM (THREAD_SELF, tid);
+#endif
+
+  /* We need to prevent the getpid() code to update the PID field so
+     that, if a signal arrives in the child very early and the signal
+     handler uses getpid(), the value returned is correct.  */
+  pid_t parentpid = THREAD_GETMEM (THREAD_SELF, pid);
+  THREAD_SETMEM (THREAD_SELF, pid, -parentpid);
+
+#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;
+
+      assert (THREAD_GETMEM (self, tid) != ppid);
+
+      if (__fork_generation_pointer != NULL)
+	*__fork_generation_pointer += 4;
+
+      /* Adjust the PID field for the new process.  */
+      THREAD_SETMEM (self, pid, THREAD_GETMEM (self, tid));
+
+#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 which has been reset during
+	 the fork.  We do not check for errors since if it fails here
+	 it failed at process start as well and noone could have used
+	 robust mutexes.  We also do not have to set
+	 self->robust_head.futex_offset since we inherit the correct
+	 value from the parent.  */
+# 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 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
+    {
+      assert (THREAD_GETMEM (THREAD_SELF, tid) == ppid);
+
+      /* Restore the PID value.  */
+      THREAD_SETMEM (THREAD_SELF, pid, parentpid);
+
+      /* 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)
+	    lll_futex_wake (allp->handler->refcntr, 1, LLL_PRIVATE);
+
+	  allp = allp->next;
+	}
+    }
+
+  return pid;
+}
+weak_alias (__libc_fork, __fork)
+libc_hidden_def (__fork)
+weak_alias (__libc_fork, fork)