diff options
Diffstat (limited to 'sysdeps/nptl/fork.c')
| -rw-r--r-- | sysdeps/nptl/fork.c | 255 |
1 files changed, 0 insertions, 255 deletions
diff --git a/sysdeps/nptl/fork.c b/sysdeps/nptl/fork.c deleted file mode 100644 index 4bb87e2331..0000000000 --- a/sysdeps/nptl/fork.c +++ /dev/null @@ -1,255 +0,0 @@ -/* 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) |