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-rw-r--r--sysdeps/nptl/fork.c238
-rw-r--r--sysdeps/nptl/fork.h59
-rw-r--r--sysdeps/nptl/jmp-unwind.c38
-rw-r--r--sysdeps/nptl/lowlevellock.h83
4 files changed, 418 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)
diff --git a/sysdeps/nptl/fork.h b/sysdeps/nptl/fork.h
new file mode 100644
index 0000000000..8e28a76098
--- /dev/null
+++ b/sysdeps/nptl/fork.h
@@ -0,0 +1,59 @@
+/* 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 <lowlevellock.h>
+
+/* The fork generation counter, defined in libpthread. */
+extern unsigned long int __fork_generation attribute_hidden;
+
+/* Pointer to the fork generation counter in the thread library. */
+extern unsigned long int *__fork_generation_pointer attribute_hidden;
+
+/* Lock to protect allocation and deallocation of fork handlers. */
+extern int __fork_lock attribute_hidden;
+
+/* Elements of the fork handler lists. */
+struct fork_handler
+{
+ struct fork_handler *next;
+ void (*prepare_handler) (void);
+ void (*parent_handler) (void);
+ void (*child_handler) (void);
+ void *dso_handle;
+ unsigned int refcntr;
+ int need_signal;
+};
+
+/* The single linked list of all currently registered for handlers. */
+extern struct fork_handler *__fork_handlers attribute_hidden;
+
+
+/* Function to call to unregister fork handlers. */
+extern void __unregister_atfork (void *dso_handle) attribute_hidden;
+#define UNREGISTER_ATFORK(dso_handle) __unregister_atfork (dso_handle)
+
+
+/* C library side function to register new fork handlers. */
+extern int __register_atfork (void (*__prepare) (void),
+ void (*__parent) (void),
+ void (*__child) (void),
+ void *dso_handle);
+libc_hidden_proto (__register_atfork)
+
+/* Add a new element to the fork list. */
+extern void __linkin_atfork (struct fork_handler *newp) attribute_hidden;
diff --git a/sysdeps/nptl/jmp-unwind.c b/sysdeps/nptl/jmp-unwind.c
new file mode 100644
index 0000000000..b3a960c980
--- /dev/null
+++ b/sysdeps/nptl/jmp-unwind.c
@@ -0,0 +1,38 @@
+/* Clean up stack frames unwound by longjmp. Linux version.
+ Copyright (C) 1995-2014 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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 <setjmp.h>
+#include <stddef.h>
+#include <pthreadP.h>
+
+extern void __pthread_cleanup_upto (__jmp_buf env, char *targetframe);
+#pragma weak __pthread_cleanup_upto
+
+
+void
+_longjmp_unwind (jmp_buf env, int val)
+{
+#ifdef SHARED
+ if (__libc_pthread_functions_init)
+ PTHFCT_CALL (ptr___pthread_cleanup_upto, (env->__jmpbuf,
+ CURRENT_STACK_FRAME));
+#else
+ if (__pthread_cleanup_upto != NULL)
+ __pthread_cleanup_upto (env->__jmpbuf, CURRENT_STACK_FRAME);
+#endif
+}
diff --git a/sysdeps/nptl/lowlevellock.h b/sysdeps/nptl/lowlevellock.h
new file mode 100644
index 0000000000..7d1913a58d
--- /dev/null
+++ b/sysdeps/nptl/lowlevellock.h
@@ -0,0 +1,83 @@
+/* Low level locking macros used in NPTL implementation. Stub version.
+ 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 <atomic.h>
+
+
+/* Mutex lock counter:
+ bit 31 clear means unlocked;
+ bit 31 set means locked.
+
+ All code that looks at bit 31 first increases the 'number of
+ interested threads' usage counter, which is in bits 0-30.
+
+ All negative mutex values indicate that the mutex is still locked. */
+
+
+static inline void
+__generic_mutex_lock (int *mutex)
+{
+ unsigned int v;
+
+ /* Bit 31 was clear, we got the mutex. (this is the fastpath). */
+ if (atomic_bit_test_set (mutex, 31) == 0)
+ return;
+
+ atomic_increment (mutex);
+
+ while (1)
+ {
+ if (atomic_bit_test_set (mutex, 31) == 0)
+ {
+ atomic_decrement (mutex);
+ return;
+ }
+
+ /* We have to wait now. First make sure the futex value we are
+ monitoring is truly negative (i.e. locked). */
+ v = *mutex;
+ if (v >= 0)
+ continue;
+
+ lll_futex_wait (mutex, v,
+ // XYZ check mutex flag
+ LLL_SHARED);
+ }
+}
+
+
+static inline void
+__generic_mutex_unlock (int *mutex)
+{
+ /* Adding 0x80000000 to the counter results in 0 if and only if
+ there are not other interested threads - we can return (this is
+ the fastpath). */
+ if (atomic_add_zero (mutex, 0x80000000))
+ return;
+
+ /* There are other threads waiting for this mutex, wake one of them
+ up. */
+ lll_futex_wake (mutex, 1,
+ // XYZ check mutex flag
+ LLL_SHARED);
+}
+
+
+#define lll_mutex_lock(futex) __generic_mutex_lock (&(futex))
+#define lll_mutex_unlock(futex) __generic_mutex_unlock (&(futex))
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-20 13:30:54 +0000