1338 lines
43 KiB
C
1338 lines
43 KiB
C
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/* Linuxthreads - a simple clone()-based implementation of Posix */
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/* threads for Linux. */
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/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
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/* */
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/* This program is free software; you can redistribute it and/or */
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/* modify it under the terms of the GNU Library General Public License */
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/* as published by the Free Software Foundation; either version 2 */
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/* of the License, or (at your option) any later version. */
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/* */
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/* This program is distributed in the hope that it will be useful, */
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/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
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/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
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/* GNU Library General Public License for more details. */
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/* Thread creation, initialization, and basic low-level routines */
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#include <errno.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/wait.h>
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#include <sys/resource.h>
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#include <sys/time.h>
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#include <shlib-compat.h>
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#include "pthread.h"
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#include "internals.h"
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#include "spinlock.h"
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#include "restart.h"
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#include "smp.h"
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#include <ldsodefs.h>
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#include <tls.h>
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#include <version.h>
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/* Sanity check. */
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#if !defined __SIGRTMIN || (__SIGRTMAX - __SIGRTMIN) < 3
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# error "This must not happen"
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#endif
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#if !(USE_TLS && HAVE___THREAD)
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/* These variables are used by the setup code. */
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extern int _errno;
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extern int _h_errno;
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/* We need the global/static resolver state here. */
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# include <resolv.h>
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# undef _res
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extern struct __res_state _res;
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#endif
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#ifdef USE_TLS
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/* We need only a few variables. */
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static pthread_descr manager_thread;
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#else
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/* Descriptor of the initial thread */
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struct _pthread_descr_struct __pthread_initial_thread = {
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.p_header.data.self = &__pthread_initial_thread,
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.p_nextlive = &__pthread_initial_thread,
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.p_prevlive = &__pthread_initial_thread,
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.p_tid = PTHREAD_THREADS_MAX,
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.p_lock = &__pthread_handles[0].h_lock,
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.p_start_args = PTHREAD_START_ARGS_INITIALIZER(NULL),
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#if !(USE_TLS && HAVE___THREAD)
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.p_errnop = &_errno,
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.p_h_errnop = &_h_errno,
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.p_resp = &_res,
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#endif
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.p_userstack = 1,
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.p_resume_count = __ATOMIC_INITIALIZER,
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.p_alloca_cutoff = __MAX_ALLOCA_CUTOFF
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};
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/* Descriptor of the manager thread; none of this is used but the error
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variables, the p_pid and p_priority fields,
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and the address for identification. */
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#define manager_thread (&__pthread_manager_thread)
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struct _pthread_descr_struct __pthread_manager_thread = {
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.p_header.data.self = &__pthread_manager_thread,
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.p_header.data.multiple_threads = 1,
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.p_lock = &__pthread_handles[1].h_lock,
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.p_start_args = PTHREAD_START_ARGS_INITIALIZER(__pthread_manager),
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#if !(USE_TLS && HAVE___THREAD)
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.p_errnop = &__pthread_manager_thread.p_errno,
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#endif
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.p_nr = 1,
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.p_resume_count = __ATOMIC_INITIALIZER,
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.p_alloca_cutoff = PTHREAD_STACK_MIN / 4
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};
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#endif
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/* Pointer to the main thread (the father of the thread manager thread) */
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/* Originally, this is the initial thread, but this changes after fork() */
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#ifdef USE_TLS
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pthread_descr __pthread_main_thread;
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#else
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pthread_descr __pthread_main_thread = &__pthread_initial_thread;
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#endif
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/* Limit between the stack of the initial thread (above) and the
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stacks of other threads (below). Aligned on a STACK_SIZE boundary. */
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char *__pthread_initial_thread_bos;
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/* File descriptor for sending requests to the thread manager. */
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/* Initially -1, meaning that the thread manager is not running. */
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int __pthread_manager_request = -1;
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int __pthread_multiple_threads attribute_hidden;
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/* Other end of the pipe for sending requests to the thread manager. */
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int __pthread_manager_reader;
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/* Limits of the thread manager stack */
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char *__pthread_manager_thread_bos;
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char *__pthread_manager_thread_tos;
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/* For process-wide exit() */
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int __pthread_exit_requested;
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int __pthread_exit_code;
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/* Maximum stack size. */
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size_t __pthread_max_stacksize;
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/* Nozero if the machine has more than one processor. */
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int __pthread_smp_kernel;
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#if !__ASSUME_REALTIME_SIGNALS
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/* Pointers that select new or old suspend/resume functions
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based on availability of rt signals. */
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void (*__pthread_restart)(pthread_descr) = __pthread_restart_old;
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void (*__pthread_suspend)(pthread_descr) = __pthread_suspend_old;
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int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *) = __pthread_timedsuspend_old;
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#endif /* __ASSUME_REALTIME_SIGNALS */
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/* Communicate relevant LinuxThreads constants to gdb */
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const int __pthread_threads_max = PTHREAD_THREADS_MAX;
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const int __pthread_sizeof_handle = sizeof(struct pthread_handle_struct);
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const int __pthread_offsetof_descr = offsetof(struct pthread_handle_struct,
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h_descr);
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const int __pthread_offsetof_pid = offsetof(struct _pthread_descr_struct,
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p_pid);
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const int __linuxthreads_pthread_sizeof_descr
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= sizeof(struct _pthread_descr_struct);
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const int __linuxthreads_initial_report_events;
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const char __linuxthreads_version[] = VERSION;
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/* Forward declarations */
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static void pthread_onexit_process(int retcode, void *arg);
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#ifndef HAVE_Z_NODELETE
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static void pthread_atexit_process(void *arg, int retcode);
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static void pthread_atexit_retcode(void *arg, int retcode);
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#endif
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static void pthread_handle_sigcancel(int sig);
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static void pthread_handle_sigrestart(int sig);
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static void pthread_handle_sigdebug(int sig);
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/* Signal numbers used for the communication.
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In these variables we keep track of the used variables. If the
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platform does not support any real-time signals we will define the
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values to some unreasonable value which will signal failing of all
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the functions below. */
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int __pthread_sig_restart = __SIGRTMIN;
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int __pthread_sig_cancel = __SIGRTMIN + 1;
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int __pthread_sig_debug = __SIGRTMIN + 2;
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extern int __libc_current_sigrtmin_private (void);
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#if !__ASSUME_REALTIME_SIGNALS
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static int rtsigs_initialized;
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static void
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init_rtsigs (void)
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{
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if (rtsigs_initialized)
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return;
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if (__libc_current_sigrtmin_private () == -1)
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{
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__pthread_sig_restart = SIGUSR1;
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__pthread_sig_cancel = SIGUSR2;
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__pthread_sig_debug = 0;
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}
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else
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{
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__pthread_restart = __pthread_restart_new;
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__pthread_suspend = __pthread_wait_for_restart_signal;
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__pthread_timedsuspend = __pthread_timedsuspend_new;
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}
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rtsigs_initialized = 1;
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}
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#endif
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/* Initialize the pthread library.
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Initialization is split in two functions:
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- a constructor function that blocks the __pthread_sig_restart signal
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(must do this very early, since the program could capture the signal
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mask with e.g. sigsetjmp before creating the first thread);
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- a regular function called from pthread_create when needed. */
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static void pthread_initialize(void) __attribute__((constructor));
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#ifndef HAVE_Z_NODELETE
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extern void *__dso_handle __attribute__ ((weak));
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#endif
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#if defined USE_TLS && !defined SHARED
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extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
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#endif
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struct pthread_functions __pthread_functions =
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{
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#if !(USE_TLS && HAVE___THREAD)
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.ptr_pthread_internal_tsd_set = __pthread_internal_tsd_set,
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.ptr_pthread_internal_tsd_get = __pthread_internal_tsd_get,
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.ptr_pthread_internal_tsd_address = __pthread_internal_tsd_address,
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#endif
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.ptr_pthread_fork = __pthread_fork,
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.ptr_pthread_attr_destroy = __pthread_attr_destroy,
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#if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
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.ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0,
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#endif
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.ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1,
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.ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate,
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.ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate,
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.ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched,
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.ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched,
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.ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam,
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.ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam,
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.ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy,
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.ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy,
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.ptr_pthread_attr_getscope = __pthread_attr_getscope,
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.ptr_pthread_attr_setscope = __pthread_attr_setscope,
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.ptr_pthread_condattr_destroy = __pthread_condattr_destroy,
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.ptr_pthread_condattr_init = __pthread_condattr_init,
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.ptr___pthread_cond_broadcast = __pthread_cond_broadcast,
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.ptr___pthread_cond_destroy = __pthread_cond_destroy,
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.ptr___pthread_cond_init = __pthread_cond_init,
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.ptr___pthread_cond_signal = __pthread_cond_signal,
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.ptr___pthread_cond_wait = __pthread_cond_wait,
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.ptr_pthread_equal = __pthread_equal,
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.ptr___pthread_exit = __pthread_exit,
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.ptr_pthread_getschedparam = __pthread_getschedparam,
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.ptr_pthread_setschedparam = __pthread_setschedparam,
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.ptr_pthread_mutex_destroy = __pthread_mutex_destroy,
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.ptr_pthread_mutex_init = __pthread_mutex_init,
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.ptr_pthread_mutex_lock = __pthread_mutex_lock,
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.ptr_pthread_mutex_trylock = __pthread_mutex_trylock,
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.ptr_pthread_mutex_unlock = __pthread_mutex_unlock,
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.ptr_pthread_self = __pthread_self,
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.ptr_pthread_setcancelstate = __pthread_setcancelstate,
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.ptr_pthread_setcanceltype = __pthread_setcanceltype,
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.ptr_pthread_do_exit = __pthread_do_exit,
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.ptr_pthread_thread_self = __pthread_thread_self,
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.ptr_pthread_cleanup_upto = __pthread_cleanup_upto,
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.ptr_pthread_sigaction = __pthread_sigaction,
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.ptr_pthread_sigwait = __pthread_sigwait,
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.ptr_pthread_raise = __pthread_raise
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};
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#ifdef SHARED
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# define ptr_pthread_functions &__pthread_functions
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#else
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# define ptr_pthread_functions NULL
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#endif
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static int *__libc_multiple_threads_ptr;
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/* Do some minimal initialization which has to be done during the
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startup of the C library. */
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void
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__pthread_initialize_minimal(void)
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{
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#ifdef USE_TLS
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pthread_descr self;
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/* First of all init __pthread_handles[0] and [1] if needed. */
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# if __LT_SPINLOCK_INIT != 0
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__pthread_handles[0].h_lock = __LOCK_INITIALIZER;
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__pthread_handles[1].h_lock = __LOCK_INITIALIZER;
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# endif
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# ifndef SHARED
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/* Unlike in the dynamically linked case the dynamic linker has not
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taken care of initializing the TLS data structures. */
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__libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
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# elif !USE___THREAD
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if (__builtin_expect (GL(dl_tls_dtv_slotinfo_list) == NULL, 0))
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{
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tcbhead_t *tcbp;
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/* There is no actual TLS being used, so the thread register
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was not initialized in the dynamic linker. */
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/* We need to install special hooks so that the malloc and memalign
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calls in _dl_tls_setup and _dl_allocate_tls won't cause full
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malloc initialization that will try to set up its thread state. */
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extern void __libc_malloc_pthread_startup (bool first_time);
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__libc_malloc_pthread_startup (true);
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if (__builtin_expect (_dl_tls_setup (), 0)
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|| __builtin_expect ((tcbp = _dl_allocate_tls (NULL)) == NULL, 0))
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{
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static const char msg[] = "\
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cannot allocate TLS data structures for initial thread\n";
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TEMP_FAILURE_RETRY (__libc_write (STDERR_FILENO,
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msg, sizeof msg - 1));
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abort ();
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}
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const char *lossage = TLS_INIT_TP (tcbp, 0);
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if (__builtin_expect (lossage != NULL, 0))
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{
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static const char msg[] = "cannot set up thread-local storage: ";
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const char nl = '\n';
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TEMP_FAILURE_RETRY (__libc_write (STDERR_FILENO,
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msg, sizeof msg - 1));
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TEMP_FAILURE_RETRY (__libc_write (STDERR_FILENO,
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lossage, strlen (lossage)));
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TEMP_FAILURE_RETRY (__libc_write (STDERR_FILENO, &nl, 1));
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}
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/* Though it was allocated with libc's malloc, that was done without
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the user's __malloc_hook installed. A later realloc that uses
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the hooks might not work with that block from the plain malloc.
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So we record this block as unfreeable just as the dynamic linker
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does when it allocates the DTV before the libc malloc exists. */
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GL(dl_initial_dtv) = GET_DTV (tcbp);
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__libc_malloc_pthread_startup (false);
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}
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# endif
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self = THREAD_SELF;
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/* The memory for the thread descriptor was allocated elsewhere as
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part of the TLS allocation. We have to initialize the data
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structure by hand. This initialization must mirror the struct
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definition above. */
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self->p_nextlive = self->p_prevlive = self;
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self->p_tid = PTHREAD_THREADS_MAX;
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self->p_lock = &__pthread_handles[0].h_lock;
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# ifndef HAVE___THREAD
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self->p_errnop = &_errno;
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self->p_h_errnop = &_h_errno;
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# endif
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/* self->p_start_args need not be initialized, it's all zero. */
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self->p_userstack = 1;
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# if __LT_SPINLOCK_INIT != 0
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self->p_resume_count = (struct pthread_atomic) __ATOMIC_INITIALIZER;
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# endif
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self->p_alloca_cutoff = __MAX_ALLOCA_CUTOFF;
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/* Another variable which points to the thread descriptor. */
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__pthread_main_thread = self;
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/* And fill in the pointer the the thread __pthread_handles array. */
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__pthread_handles[0].h_descr = self;
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#else /* USE_TLS */
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/* First of all init __pthread_handles[0] and [1]. */
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# if __LT_SPINLOCK_INIT != 0
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__pthread_handles[0].h_lock = __LOCK_INITIALIZER;
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__pthread_handles[1].h_lock = __LOCK_INITIALIZER;
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# endif
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__pthread_handles[0].h_descr = &__pthread_initial_thread;
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__pthread_handles[1].h_descr = &__pthread_manager_thread;
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/* If we have special thread_self processing, initialize that for the
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main thread now. */
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# ifdef INIT_THREAD_SELF
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INIT_THREAD_SELF(&__pthread_initial_thread, 0);
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# endif
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#endif
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#if HP_TIMING_AVAIL
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# ifdef USE_TLS
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self->p_cpuclock_offset = GL(dl_cpuclock_offset);
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# else
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__pthread_initial_thread.p_cpuclock_offset = GL(dl_cpuclock_offset);
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# endif
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#endif
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__libc_multiple_threads_ptr = __libc_pthread_init (ptr_pthread_functions);
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}
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void
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__pthread_init_max_stacksize(void)
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{
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struct rlimit limit;
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size_t max_stack;
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getrlimit(RLIMIT_STACK, &limit);
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#ifdef FLOATING_STACKS
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if (limit.rlim_cur == RLIM_INFINITY)
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limit.rlim_cur = ARCH_STACK_MAX_SIZE;
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# ifdef NEED_SEPARATE_REGISTER_STACK
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max_stack = limit.rlim_cur / 2;
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# else
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max_stack = limit.rlim_cur;
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# endif
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#else
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/* Play with the stack size limit to make sure that no stack ever grows
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beyond STACK_SIZE minus one page (to act as a guard page). */
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# ifdef NEED_SEPARATE_REGISTER_STACK
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/* STACK_SIZE bytes hold both the main stack and register backing
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store. The rlimit value applies to each individually. */
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max_stack = STACK_SIZE/2 - __getpagesize ();
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# else
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max_stack = STACK_SIZE - __getpagesize();
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# endif
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if (limit.rlim_cur > max_stack) {
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limit.rlim_cur = max_stack;
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setrlimit(RLIMIT_STACK, &limit);
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}
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#endif
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__pthread_max_stacksize = max_stack;
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if (max_stack / 4 < __MAX_ALLOCA_CUTOFF)
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{
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#ifdef USE_TLS
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pthread_descr self = THREAD_SELF;
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self->p_alloca_cutoff = max_stack / 4;
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#else
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__pthread_initial_thread.p_alloca_cutoff = max_stack / 4;
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#endif
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}
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}
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#ifdef SHARED
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# if USE___THREAD
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/* When using __thread for this, we do it in libc so as not
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to give libpthread its own TLS segment just for this. */
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|
extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
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# else
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static void ** __attribute__ ((const))
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__libc_dl_error_tsd (void)
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{
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return &thread_self ()->p_libc_specific[_LIBC_TSD_KEY_DL_ERROR];
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}
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# endif
|
|
#endif
|
|
|
|
static void pthread_initialize(void)
|
|
{
|
|
struct sigaction sa;
|
|
sigset_t mask;
|
|
|
|
/* If already done (e.g. by a constructor called earlier!), bail out */
|
|
if (__pthread_initial_thread_bos != NULL) return;
|
|
#ifdef TEST_FOR_COMPARE_AND_SWAP
|
|
/* Test if compare-and-swap is available */
|
|
__pthread_has_cas = compare_and_swap_is_available();
|
|
#endif
|
|
#ifdef FLOATING_STACKS
|
|
/* We don't need to know the bottom of the stack. Give the pointer some
|
|
value to signal that initialization happened. */
|
|
__pthread_initial_thread_bos = (void *) -1l;
|
|
#else
|
|
/* Determine stack size limits . */
|
|
__pthread_init_max_stacksize ();
|
|
# ifdef _STACK_GROWS_UP
|
|
/* The initial thread already has all the stack it needs */
|
|
__pthread_initial_thread_bos = (char *)
|
|
((long)CURRENT_STACK_FRAME &~ (STACK_SIZE - 1));
|
|
# else
|
|
/* For the initial stack, reserve at least STACK_SIZE bytes of stack
|
|
below the current stack address, and align that on a
|
|
STACK_SIZE boundary. */
|
|
__pthread_initial_thread_bos =
|
|
(char *)(((long)CURRENT_STACK_FRAME - 2 * STACK_SIZE) & ~(STACK_SIZE - 1));
|
|
# endif
|
|
#endif
|
|
#ifdef USE_TLS
|
|
/* Update the descriptor for the initial thread. */
|
|
THREAD_SETMEM (((pthread_descr) NULL), p_pid, __getpid());
|
|
# ifndef HAVE___THREAD
|
|
/* Likewise for the resolver state _res. */
|
|
THREAD_SETMEM (((pthread_descr) NULL), p_resp, &_res);
|
|
# endif
|
|
#else
|
|
/* Update the descriptor for the initial thread. */
|
|
__pthread_initial_thread.p_pid = __getpid();
|
|
/* Likewise for the resolver state _res. */
|
|
__pthread_initial_thread.p_resp = &_res;
|
|
#endif
|
|
#if !__ASSUME_REALTIME_SIGNALS
|
|
/* Initialize real-time signals. */
|
|
init_rtsigs ();
|
|
#endif
|
|
/* Setup signal handlers for the initial thread.
|
|
Since signal handlers are shared between threads, these settings
|
|
will be inherited by all other threads. */
|
|
sa.sa_handler = pthread_handle_sigrestart;
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags = 0;
|
|
__libc_sigaction(__pthread_sig_restart, &sa, NULL);
|
|
sa.sa_handler = pthread_handle_sigcancel;
|
|
// sa.sa_flags = 0;
|
|
__libc_sigaction(__pthread_sig_cancel, &sa, NULL);
|
|
if (__pthread_sig_debug > 0) {
|
|
sa.sa_handler = pthread_handle_sigdebug;
|
|
sigemptyset(&sa.sa_mask);
|
|
// sa.sa_flags = 0;
|
|
__libc_sigaction(__pthread_sig_debug, &sa, NULL);
|
|
}
|
|
/* Initially, block __pthread_sig_restart. Will be unblocked on demand. */
|
|
sigemptyset(&mask);
|
|
sigaddset(&mask, __pthread_sig_restart);
|
|
sigprocmask(SIG_BLOCK, &mask, NULL);
|
|
/* Register an exit function to kill all other threads. */
|
|
/* Do it early so that user-registered atexit functions are called
|
|
before pthread_*exit_process. */
|
|
#ifndef HAVE_Z_NODELETE
|
|
if (__builtin_expect (&__dso_handle != NULL, 1))
|
|
__cxa_atexit ((void (*) (void *)) pthread_atexit_process, NULL,
|
|
__dso_handle);
|
|
else
|
|
#endif
|
|
__on_exit (pthread_onexit_process, NULL);
|
|
/* How many processors. */
|
|
__pthread_smp_kernel = is_smp_system ();
|
|
|
|
#ifdef SHARED
|
|
/* Transfer the old value from the dynamic linker's internal location. */
|
|
*__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
|
|
GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
|
|
#endif
|
|
}
|
|
|
|
void __pthread_initialize(void)
|
|
{
|
|
pthread_initialize();
|
|
}
|
|
|
|
int __pthread_initialize_manager(void)
|
|
{
|
|
int manager_pipe[2];
|
|
int pid;
|
|
struct pthread_request request;
|
|
int report_events;
|
|
pthread_descr mgr;
|
|
#ifdef USE_TLS
|
|
tcbhead_t *tcbp;
|
|
#endif
|
|
|
|
__pthread_multiple_threads = 1;
|
|
#if TLS_MULTIPLE_THREADS_IN_TCB || !defined USE_TLS || !TLS_DTV_AT_TP
|
|
__pthread_main_thread->p_multiple_threads = 1;
|
|
#endif
|
|
*__libc_multiple_threads_ptr = 1;
|
|
|
|
#ifndef HAVE_Z_NODELETE
|
|
if (__builtin_expect (&__dso_handle != NULL, 1))
|
|
__cxa_atexit ((void (*) (void *)) pthread_atexit_retcode, NULL,
|
|
__dso_handle);
|
|
#endif
|
|
|
|
if (__pthread_max_stacksize == 0)
|
|
__pthread_init_max_stacksize ();
|
|
/* If basic initialization not done yet (e.g. we're called from a
|
|
constructor run before our constructor), do it now */
|
|
if (__pthread_initial_thread_bos == NULL) pthread_initialize();
|
|
/* Setup stack for thread manager */
|
|
__pthread_manager_thread_bos = malloc(THREAD_MANAGER_STACK_SIZE);
|
|
if (__pthread_manager_thread_bos == NULL) return -1;
|
|
__pthread_manager_thread_tos =
|
|
__pthread_manager_thread_bos + THREAD_MANAGER_STACK_SIZE;
|
|
/* Setup pipe to communicate with thread manager */
|
|
if (pipe(manager_pipe) == -1) {
|
|
free(__pthread_manager_thread_bos);
|
|
return -1;
|
|
}
|
|
|
|
#ifdef USE_TLS
|
|
/* Allocate memory for the thread descriptor and the dtv. */
|
|
tcbp = _dl_allocate_tls (NULL);
|
|
if (tcbp == NULL) {
|
|
free(__pthread_manager_thread_bos);
|
|
__libc_close(manager_pipe[0]);
|
|
__libc_close(manager_pipe[1]);
|
|
return -1;
|
|
}
|
|
|
|
# if TLS_TCB_AT_TP
|
|
mgr = (pthread_descr) tcbp;
|
|
# elif TLS_DTV_AT_TP
|
|
/* pthread_descr is located right below tcbhead_t which _dl_allocate_tls
|
|
returns. */
|
|
mgr = (pthread_descr) tcbp - 1;
|
|
# endif
|
|
__pthread_handles[1].h_descr = manager_thread = mgr;
|
|
|
|
/* Initialize the descriptor. */
|
|
#if !defined USE_TLS || !TLS_DTV_AT_TP
|
|
mgr->p_header.data.tcb = tcbp;
|
|
mgr->p_header.data.self = mgr;
|
|
mgr->p_header.data.multiple_threads = 1;
|
|
#elif TLS_MULTIPLE_THREADS_IN_TCB
|
|
mgr->p_multiple_threads = 1;
|
|
#endif
|
|
mgr->p_lock = &__pthread_handles[1].h_lock;
|
|
# ifndef HAVE___THREAD
|
|
mgr->p_errnop = &mgr->p_errno;
|
|
# endif
|
|
mgr->p_start_args = (struct pthread_start_args) PTHREAD_START_ARGS_INITIALIZER(__pthread_manager);
|
|
mgr->p_nr = 1;
|
|
# if __LT_SPINLOCK_INIT != 0
|
|
self->p_resume_count = (struct pthread_atomic) __ATOMIC_INITIALIZER;
|
|
# endif
|
|
mgr->p_alloca_cutoff = PTHREAD_STACK_MIN / 4;
|
|
#else
|
|
mgr = &__pthread_manager_thread;
|
|
#endif
|
|
|
|
__pthread_manager_request = manager_pipe[1]; /* writing end */
|
|
__pthread_manager_reader = manager_pipe[0]; /* reading end */
|
|
|
|
/* Start the thread manager */
|
|
pid = 0;
|
|
#ifdef USE_TLS
|
|
if (__linuxthreads_initial_report_events != 0)
|
|
THREAD_SETMEM (((pthread_descr) NULL), p_report_events,
|
|
__linuxthreads_initial_report_events);
|
|
report_events = THREAD_GETMEM (((pthread_descr) NULL), p_report_events);
|
|
#else
|
|
if (__linuxthreads_initial_report_events != 0)
|
|
__pthread_initial_thread.p_report_events
|
|
= __linuxthreads_initial_report_events;
|
|
report_events = __pthread_initial_thread.p_report_events;
|
|
#endif
|
|
if (__builtin_expect (report_events, 0))
|
|
{
|
|
/* It's a bit more complicated. We have to report the creation of
|
|
the manager thread. */
|
|
int idx = __td_eventword (TD_CREATE);
|
|
uint32_t mask = __td_eventmask (TD_CREATE);
|
|
uint32_t event_bits;
|
|
|
|
#ifdef USE_TLS
|
|
event_bits = THREAD_GETMEM_NC (((pthread_descr) NULL),
|
|
p_eventbuf.eventmask.event_bits[idx]);
|
|
#else
|
|
event_bits = __pthread_initial_thread.p_eventbuf.eventmask.event_bits[idx];
|
|
#endif
|
|
|
|
if ((mask & (__pthread_threads_events.event_bits[idx] | event_bits))
|
|
!= 0)
|
|
{
|
|
__pthread_lock(mgr->p_lock, NULL);
|
|
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
pid = __clone2(__pthread_manager_event,
|
|
(void **) __pthread_manager_thread_bos,
|
|
THREAD_MANAGER_STACK_SIZE,
|
|
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
|
|
mgr);
|
|
#elif _STACK_GROWS_UP
|
|
pid = __clone(__pthread_manager_event,
|
|
(void **) __pthread_manager_thread_bos,
|
|
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
|
|
mgr);
|
|
#else
|
|
pid = __clone(__pthread_manager_event,
|
|
(void **) __pthread_manager_thread_tos,
|
|
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
|
|
mgr);
|
|
#endif
|
|
|
|
if (pid != -1)
|
|
{
|
|
/* Now fill in the information about the new thread in
|
|
the newly created thread's data structure. We cannot let
|
|
the new thread do this since we don't know whether it was
|
|
already scheduled when we send the event. */
|
|
mgr->p_eventbuf.eventdata = mgr;
|
|
mgr->p_eventbuf.eventnum = TD_CREATE;
|
|
__pthread_last_event = mgr;
|
|
mgr->p_tid = 2* PTHREAD_THREADS_MAX + 1;
|
|
mgr->p_pid = pid;
|
|
|
|
/* Now call the function which signals the event. */
|
|
__linuxthreads_create_event ();
|
|
}
|
|
|
|
/* Now restart the thread. */
|
|
__pthread_unlock(mgr->p_lock);
|
|
}
|
|
}
|
|
|
|
if (__builtin_expect (pid, 0) == 0)
|
|
{
|
|
#ifdef NEED_SEPARATE_REGISTER_STACK
|
|
pid = __clone2(__pthread_manager, (void **) __pthread_manager_thread_bos,
|
|
THREAD_MANAGER_STACK_SIZE,
|
|
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND, mgr);
|
|
#elif _STACK_GROWS_UP
|
|
pid = __clone(__pthread_manager, (void **) __pthread_manager_thread_bos,
|
|
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND, mgr);
|
|
#else
|
|
pid = __clone(__pthread_manager, (void **) __pthread_manager_thread_tos,
|
|
CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND, mgr);
|
|
#endif
|
|
}
|
|
if (__builtin_expect (pid, 0) == -1) {
|
|
free(__pthread_manager_thread_bos);
|
|
__libc_close(manager_pipe[0]);
|
|
__libc_close(manager_pipe[1]);
|
|
return -1;
|
|
}
|
|
mgr->p_tid = 2* PTHREAD_THREADS_MAX + 1;
|
|
mgr->p_pid = pid;
|
|
/* Make gdb aware of new thread manager */
|
|
if (__builtin_expect (__pthread_threads_debug, 0) && __pthread_sig_debug > 0)
|
|
{
|
|
raise(__pthread_sig_debug);
|
|
/* We suspend ourself and gdb will wake us up when it is
|
|
ready to handle us. */
|
|
__pthread_wait_for_restart_signal(thread_self());
|
|
}
|
|
/* Synchronize debugging of the thread manager */
|
|
request.req_kind = REQ_DEBUG;
|
|
TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
|
|
(char *) &request, sizeof(request)));
|
|
return 0;
|
|
}
|
|
|
|
/* Thread creation */
|
|
|
|
int __pthread_create_2_1(pthread_t *thread, const pthread_attr_t *attr,
|
|
void * (*start_routine)(void *), void *arg)
|
|
{
|
|
pthread_descr self = thread_self();
|
|
struct pthread_request request;
|
|
int retval;
|
|
if (__builtin_expect (__pthread_manager_request, 0) < 0) {
|
|
if (__pthread_initialize_manager() < 0) return EAGAIN;
|
|
}
|
|
request.req_thread = self;
|
|
request.req_kind = REQ_CREATE;
|
|
request.req_args.create.attr = attr;
|
|
request.req_args.create.fn = start_routine;
|
|
request.req_args.create.arg = arg;
|
|
sigprocmask(SIG_SETMASK, (const sigset_t *) NULL,
|
|
&request.req_args.create.mask);
|
|
TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
|
|
(char *) &request, sizeof(request)));
|
|
suspend(self);
|
|
retval = THREAD_GETMEM(self, p_retcode);
|
|
if (__builtin_expect (retval, 0) == 0)
|
|
*thread = (pthread_t) THREAD_GETMEM(self, p_retval);
|
|
return retval;
|
|
}
|
|
|
|
versioned_symbol (libpthread, __pthread_create_2_1, pthread_create, GLIBC_2_1);
|
|
|
|
#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
|
|
|
|
int __pthread_create_2_0(pthread_t *thread, const pthread_attr_t *attr,
|
|
void * (*start_routine)(void *), void *arg)
|
|
{
|
|
/* The ATTR attribute is not really of type `pthread_attr_t *'. It has
|
|
the old size and access to the new members might crash the program.
|
|
We convert the struct now. */
|
|
pthread_attr_t new_attr;
|
|
|
|
if (attr != NULL)
|
|
{
|
|
size_t ps = __getpagesize ();
|
|
|
|
memcpy (&new_attr, attr,
|
|
(size_t) &(((pthread_attr_t*)NULL)->__guardsize));
|
|
new_attr.__guardsize = ps;
|
|
new_attr.__stackaddr_set = 0;
|
|
new_attr.__stackaddr = NULL;
|
|
new_attr.__stacksize = STACK_SIZE - ps;
|
|
attr = &new_attr;
|
|
}
|
|
return __pthread_create_2_1 (thread, attr, start_routine, arg);
|
|
}
|
|
compat_symbol (libpthread, __pthread_create_2_0, pthread_create, GLIBC_2_0);
|
|
#endif
|
|
|
|
/* Simple operations on thread identifiers */
|
|
|
|
pthread_descr __pthread_thread_self(void)
|
|
{
|
|
return thread_self();
|
|
}
|
|
|
|
pthread_t __pthread_self(void)
|
|
{
|
|
pthread_descr self = thread_self();
|
|
return THREAD_GETMEM(self, p_tid);
|
|
}
|
|
strong_alias (__pthread_self, pthread_self);
|
|
|
|
int __pthread_equal(pthread_t thread1, pthread_t thread2)
|
|
{
|
|
return thread1 == thread2;
|
|
}
|
|
strong_alias (__pthread_equal, pthread_equal);
|
|
|
|
/* Helper function for thread_self in the case of user-provided stacks */
|
|
|
|
#ifndef THREAD_SELF
|
|
|
|
pthread_descr __pthread_find_self(void)
|
|
{
|
|
char * sp = CURRENT_STACK_FRAME;
|
|
pthread_handle h;
|
|
|
|
/* __pthread_handles[0] is the initial thread, __pthread_handles[1] is
|
|
the manager threads handled specially in thread_self(), so start at 2 */
|
|
h = __pthread_handles + 2;
|
|
while (! (sp <= (char *) h->h_descr && sp >= h->h_bottom)) h++;
|
|
return h->h_descr;
|
|
}
|
|
|
|
#else
|
|
|
|
static pthread_descr thread_self_stack(void)
|
|
{
|
|
char *sp = CURRENT_STACK_FRAME;
|
|
pthread_handle h;
|
|
|
|
if (sp >= __pthread_manager_thread_bos && sp < __pthread_manager_thread_tos)
|
|
return manager_thread;
|
|
h = __pthread_handles + 2;
|
|
# ifdef USE_TLS
|
|
while (h->h_descr == NULL
|
|
|| ! (sp <= (char *) h->h_descr->p_stackaddr && sp >= h->h_bottom))
|
|
h++;
|
|
# else
|
|
while (! (sp <= (char *) h->h_descr && sp >= h->h_bottom))
|
|
h++;
|
|
# endif
|
|
return h->h_descr;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* Thread scheduling */
|
|
|
|
int __pthread_setschedparam(pthread_t thread, int policy,
|
|
const struct sched_param *param)
|
|
{
|
|
pthread_handle handle = thread_handle(thread);
|
|
pthread_descr th;
|
|
|
|
__pthread_lock(&handle->h_lock, NULL);
|
|
if (__builtin_expect (invalid_handle(handle, thread), 0)) {
|
|
__pthread_unlock(&handle->h_lock);
|
|
return ESRCH;
|
|
}
|
|
th = handle->h_descr;
|
|
if (__builtin_expect (__sched_setscheduler(th->p_pid, policy, param) == -1,
|
|
0)) {
|
|
__pthread_unlock(&handle->h_lock);
|
|
return errno;
|
|
}
|
|
th->p_priority = policy == SCHED_OTHER ? 0 : param->sched_priority;
|
|
__pthread_unlock(&handle->h_lock);
|
|
if (__pthread_manager_request >= 0)
|
|
__pthread_manager_adjust_prio(th->p_priority);
|
|
return 0;
|
|
}
|
|
strong_alias (__pthread_setschedparam, pthread_setschedparam);
|
|
|
|
int __pthread_getschedparam(pthread_t thread, int *policy,
|
|
struct sched_param *param)
|
|
{
|
|
pthread_handle handle = thread_handle(thread);
|
|
int pid, pol;
|
|
|
|
__pthread_lock(&handle->h_lock, NULL);
|
|
if (__builtin_expect (invalid_handle(handle, thread), 0)) {
|
|
__pthread_unlock(&handle->h_lock);
|
|
return ESRCH;
|
|
}
|
|
pid = handle->h_descr->p_pid;
|
|
__pthread_unlock(&handle->h_lock);
|
|
pol = __sched_getscheduler(pid);
|
|
if (__builtin_expect (pol, 0) == -1) return errno;
|
|
if (__sched_getparam(pid, param) == -1) return errno;
|
|
*policy = pol;
|
|
return 0;
|
|
}
|
|
strong_alias (__pthread_getschedparam, pthread_getschedparam);
|
|
|
|
int __pthread_yield (void)
|
|
{
|
|
/* For now this is equivalent with the POSIX call. */
|
|
return sched_yield ();
|
|
}
|
|
weak_alias (__pthread_yield, pthread_yield)
|
|
|
|
/* Process-wide exit() request */
|
|
|
|
static void pthread_onexit_process(int retcode, void *arg)
|
|
{
|
|
if (__builtin_expect (__pthread_manager_request, 0) >= 0) {
|
|
struct pthread_request request;
|
|
pthread_descr self = thread_self();
|
|
|
|
request.req_thread = self;
|
|
request.req_kind = REQ_PROCESS_EXIT;
|
|
request.req_args.exit.code = retcode;
|
|
TEMP_FAILURE_RETRY(__libc_write(__pthread_manager_request,
|
|
(char *) &request, sizeof(request)));
|
|
suspend(self);
|
|
/* Main thread should accumulate times for thread manager and its
|
|
children, so that timings for main thread account for all threads. */
|
|
if (self == __pthread_main_thread)
|
|
{
|
|
#ifdef USE_TLS
|
|
waitpid(manager_thread->p_pid, NULL, __WCLONE);
|
|
#else
|
|
waitpid(__pthread_manager_thread.p_pid, NULL, __WCLONE);
|
|
#endif
|
|
/* Since all threads have been asynchronously terminated
|
|
(possibly holding locks), free cannot be used any more. */
|
|
/*free (__pthread_manager_thread_bos);*/
|
|
__pthread_manager_thread_bos = __pthread_manager_thread_tos = NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifndef HAVE_Z_NODELETE
|
|
static int __pthread_atexit_retcode;
|
|
|
|
static void pthread_atexit_process(void *arg, int retcode)
|
|
{
|
|
pthread_onexit_process (retcode ?: __pthread_atexit_retcode, arg);
|
|
}
|
|
|
|
static void pthread_atexit_retcode(void *arg, int retcode)
|
|
{
|
|
__pthread_atexit_retcode = retcode;
|
|
}
|
|
#endif
|
|
|
|
/* The handler for the RESTART signal just records the signal received
|
|
in the thread descriptor, and optionally performs a siglongjmp
|
|
(for pthread_cond_timedwait). */
|
|
|
|
static void pthread_handle_sigrestart(int sig)
|
|
{
|
|
pthread_descr self = thread_self();
|
|
THREAD_SETMEM(self, p_signal, sig);
|
|
if (THREAD_GETMEM(self, p_signal_jmp) != NULL)
|
|
siglongjmp(*THREAD_GETMEM(self, p_signal_jmp), 1);
|
|
}
|
|
|
|
/* The handler for the CANCEL signal checks for cancellation
|
|
(in asynchronous mode), for process-wide exit and exec requests.
|
|
For the thread manager thread, redirect the signal to
|
|
__pthread_manager_sighandler. */
|
|
|
|
static void pthread_handle_sigcancel(int sig)
|
|
{
|
|
pthread_descr self = thread_self();
|
|
sigjmp_buf * jmpbuf;
|
|
|
|
if (self == manager_thread)
|
|
{
|
|
#ifdef THREAD_SELF
|
|
/* A new thread might get a cancel signal before it is fully
|
|
initialized, so that the thread register might still point to the
|
|
manager thread. Double check that this is really the manager
|
|
thread. */
|
|
pthread_descr real_self = thread_self_stack();
|
|
if (real_self == manager_thread)
|
|
{
|
|
__pthread_manager_sighandler(sig);
|
|
return;
|
|
}
|
|
/* Oops, thread_self() isn't working yet.. */
|
|
self = real_self;
|
|
# ifdef INIT_THREAD_SELF
|
|
INIT_THREAD_SELF(self, self->p_nr);
|
|
# endif
|
|
#else
|
|
__pthread_manager_sighandler(sig);
|
|
return;
|
|
#endif
|
|
}
|
|
if (__builtin_expect (__pthread_exit_requested, 0)) {
|
|
/* Main thread should accumulate times for thread manager and its
|
|
children, so that timings for main thread account for all threads. */
|
|
if (self == __pthread_main_thread) {
|
|
#ifdef USE_TLS
|
|
waitpid(manager_thread->p_pid, NULL, __WCLONE);
|
|
#else
|
|
waitpid(__pthread_manager_thread.p_pid, NULL, __WCLONE);
|
|
#endif
|
|
}
|
|
_exit(__pthread_exit_code);
|
|
}
|
|
if (__builtin_expect (THREAD_GETMEM(self, p_canceled), 0)
|
|
&& THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) {
|
|
if (THREAD_GETMEM(self, p_canceltype) == PTHREAD_CANCEL_ASYNCHRONOUS)
|
|
__pthread_do_exit(PTHREAD_CANCELED, CURRENT_STACK_FRAME);
|
|
jmpbuf = THREAD_GETMEM(self, p_cancel_jmp);
|
|
if (jmpbuf != NULL) {
|
|
THREAD_SETMEM(self, p_cancel_jmp, NULL);
|
|
siglongjmp(*jmpbuf, 1);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Handler for the DEBUG signal.
|
|
The debugging strategy is as follows:
|
|
On reception of a REQ_DEBUG request (sent by new threads created to
|
|
the thread manager under debugging mode), the thread manager throws
|
|
__pthread_sig_debug to itself. The debugger (if active) intercepts
|
|
this signal, takes into account new threads and continue execution
|
|
of the thread manager by propagating the signal because it doesn't
|
|
know what it is specifically done for. In the current implementation,
|
|
the thread manager simply discards it. */
|
|
|
|
static void pthread_handle_sigdebug(int sig)
|
|
{
|
|
/* Nothing */
|
|
}
|
|
|
|
/* Reset the state of the thread machinery after a fork().
|
|
Close the pipe used for requests and set the main thread to the forked
|
|
thread.
|
|
Notice that we can't free the stack segments, as the forked thread
|
|
may hold pointers into them. */
|
|
|
|
void __pthread_reset_main_thread(void)
|
|
{
|
|
pthread_descr self = thread_self();
|
|
|
|
if (__pthread_manager_request != -1) {
|
|
/* Free the thread manager stack */
|
|
free(__pthread_manager_thread_bos);
|
|
__pthread_manager_thread_bos = __pthread_manager_thread_tos = NULL;
|
|
/* Close the two ends of the pipe */
|
|
__libc_close(__pthread_manager_request);
|
|
__libc_close(__pthread_manager_reader);
|
|
__pthread_manager_request = __pthread_manager_reader = -1;
|
|
}
|
|
|
|
/* Update the pid of the main thread */
|
|
THREAD_SETMEM(self, p_pid, __getpid());
|
|
/* Make the forked thread the main thread */
|
|
__pthread_main_thread = self;
|
|
THREAD_SETMEM(self, p_nextlive, self);
|
|
THREAD_SETMEM(self, p_prevlive, self);
|
|
#if !(USE_TLS && HAVE___THREAD)
|
|
/* Now this thread modifies the global variables. */
|
|
THREAD_SETMEM(self, p_errnop, &_errno);
|
|
THREAD_SETMEM(self, p_h_errnop, &_h_errno);
|
|
THREAD_SETMEM(self, p_resp, &_res);
|
|
#endif
|
|
|
|
#ifndef FLOATING_STACKS
|
|
/* This is to undo the setrlimit call in __pthread_init_max_stacksize.
|
|
XXX This can be wrong if the user set the limit during the run. */
|
|
{
|
|
struct rlimit limit;
|
|
if (getrlimit (RLIMIT_STACK, &limit) == 0
|
|
&& limit.rlim_cur != limit.rlim_max)
|
|
{
|
|
limit.rlim_cur = limit.rlim_max;
|
|
setrlimit(RLIMIT_STACK, &limit);
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/* Process-wide exec() request */
|
|
|
|
void __pthread_kill_other_threads_np(void)
|
|
{
|
|
struct sigaction sa;
|
|
/* Terminate all other threads and thread manager */
|
|
pthread_onexit_process(0, NULL);
|
|
/* Make current thread the main thread in case the calling thread
|
|
changes its mind, does not exec(), and creates new threads instead. */
|
|
__pthread_reset_main_thread();
|
|
|
|
/* Reset the signal handlers behaviour for the signals the
|
|
implementation uses since this would be passed to the new
|
|
process. */
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags = 0;
|
|
sa.sa_handler = SIG_DFL;
|
|
__libc_sigaction(__pthread_sig_restart, &sa, NULL);
|
|
__libc_sigaction(__pthread_sig_cancel, &sa, NULL);
|
|
if (__pthread_sig_debug > 0)
|
|
__libc_sigaction(__pthread_sig_debug, &sa, NULL);
|
|
}
|
|
weak_alias (__pthread_kill_other_threads_np, pthread_kill_other_threads_np)
|
|
|
|
/* Concurrency symbol level. */
|
|
static int current_level;
|
|
|
|
int __pthread_setconcurrency(int level)
|
|
{
|
|
/* We don't do anything unless we have found a useful interpretation. */
|
|
current_level = level;
|
|
return 0;
|
|
}
|
|
weak_alias (__pthread_setconcurrency, pthread_setconcurrency)
|
|
|
|
int __pthread_getconcurrency(void)
|
|
{
|
|
return current_level;
|
|
}
|
|
weak_alias (__pthread_getconcurrency, pthread_getconcurrency)
|
|
|
|
/* Primitives for controlling thread execution */
|
|
|
|
void __pthread_wait_for_restart_signal(pthread_descr self)
|
|
{
|
|
sigset_t mask;
|
|
|
|
sigprocmask(SIG_SETMASK, NULL, &mask); /* Get current signal mask */
|
|
sigdelset(&mask, __pthread_sig_restart); /* Unblock the restart signal */
|
|
THREAD_SETMEM(self, p_signal, 0);
|
|
do {
|
|
sigsuspend(&mask); /* Wait for signal */
|
|
} while (THREAD_GETMEM(self, p_signal) !=__pthread_sig_restart);
|
|
|
|
READ_MEMORY_BARRIER(); /* See comment in __pthread_restart_new */
|
|
}
|
|
|
|
#if !__ASSUME_REALTIME_SIGNALS
|
|
/* The _old variants are for 2.0 and early 2.1 kernels which don't have RT
|
|
signals.
|
|
On these kernels, we use SIGUSR1 and SIGUSR2 for restart and cancellation.
|
|
Since the restart signal does not queue, we use an atomic counter to create
|
|
queuing semantics. This is needed to resolve a rare race condition in
|
|
pthread_cond_timedwait_relative. */
|
|
|
|
void __pthread_restart_old(pthread_descr th)
|
|
{
|
|
if (atomic_increment(&th->p_resume_count) == -1)
|
|
kill(th->p_pid, __pthread_sig_restart);
|
|
}
|
|
|
|
void __pthread_suspend_old(pthread_descr self)
|
|
{
|
|
if (atomic_decrement(&self->p_resume_count) <= 0)
|
|
__pthread_wait_for_restart_signal(self);
|
|
}
|
|
|
|
int
|
|
__pthread_timedsuspend_old(pthread_descr self, const struct timespec *abstime)
|
|
{
|
|
sigset_t unblock, initial_mask;
|
|
int was_signalled = 0;
|
|
sigjmp_buf jmpbuf;
|
|
|
|
if (atomic_decrement(&self->p_resume_count) == 0) {
|
|
/* Set up a longjmp handler for the restart signal, unblock
|
|
the signal and sleep. */
|
|
|
|
if (sigsetjmp(jmpbuf, 1) == 0) {
|
|
THREAD_SETMEM(self, p_signal_jmp, &jmpbuf);
|
|
THREAD_SETMEM(self, p_signal, 0);
|
|
/* Unblock the restart signal */
|
|
sigemptyset(&unblock);
|
|
sigaddset(&unblock, __pthread_sig_restart);
|
|
sigprocmask(SIG_UNBLOCK, &unblock, &initial_mask);
|
|
|
|
while (1) {
|
|
struct timeval now;
|
|
struct timespec reltime;
|
|
|
|
/* Compute a time offset relative to now. */
|
|
__gettimeofday (&now, NULL);
|
|
reltime.tv_nsec = abstime->tv_nsec - now.tv_usec * 1000;
|
|
reltime.tv_sec = abstime->tv_sec - now.tv_sec;
|
|
if (reltime.tv_nsec < 0) {
|
|
reltime.tv_nsec += 1000000000;
|
|
reltime.tv_sec -= 1;
|
|
}
|
|
|
|
/* Sleep for the required duration. If woken by a signal,
|
|
resume waiting as required by Single Unix Specification. */
|
|
if (reltime.tv_sec < 0 || __libc_nanosleep(&reltime, NULL) == 0)
|
|
break;
|
|
}
|
|
|
|
/* Block the restart signal again */
|
|
sigprocmask(SIG_SETMASK, &initial_mask, NULL);
|
|
was_signalled = 0;
|
|
} else {
|
|
was_signalled = 1;
|
|
}
|
|
THREAD_SETMEM(self, p_signal_jmp, NULL);
|
|
}
|
|
|
|
/* Now was_signalled is true if we exited the above code
|
|
due to the delivery of a restart signal. In that case,
|
|
we know we have been dequeued and resumed and that the
|
|
resume count is balanced. Otherwise, there are some
|
|
cases to consider. First, try to bump up the resume count
|
|
back to zero. If it goes to 1, it means restart() was
|
|
invoked on this thread. The signal must be consumed
|
|
and the count bumped down and everything is cool. We
|
|
can return a 1 to the caller.
|
|
Otherwise, no restart was delivered yet, so a potential
|
|
race exists; we return a 0 to the caller which must deal
|
|
with this race in an appropriate way; for example by
|
|
atomically removing the thread from consideration for a
|
|
wakeup---if such a thing fails, it means a restart is
|
|
being delivered. */
|
|
|
|
if (!was_signalled) {
|
|
if (atomic_increment(&self->p_resume_count) != -1) {
|
|
__pthread_wait_for_restart_signal(self);
|
|
atomic_decrement(&self->p_resume_count); /* should be zero now! */
|
|
/* woke spontaneously and consumed restart signal */
|
|
return 1;
|
|
}
|
|
/* woke spontaneously but did not consume restart---caller must resolve */
|
|
return 0;
|
|
}
|
|
/* woken due to restart signal */
|
|
return 1;
|
|
}
|
|
#endif /* __ASSUME_REALTIME_SIGNALS */
|
|
|
|
void __pthread_restart_new(pthread_descr th)
|
|
{
|
|
/* The barrier is proabably not needed, in which case it still documents
|
|
our assumptions. The intent is to commit previous writes to shared
|
|
memory so the woken thread will have a consistent view. Complementary
|
|
read barriers are present to the suspend functions. */
|
|
WRITE_MEMORY_BARRIER();
|
|
kill(th->p_pid, __pthread_sig_restart);
|
|
}
|
|
|
|
/* There is no __pthread_suspend_new because it would just
|
|
be a wasteful wrapper for __pthread_wait_for_restart_signal */
|
|
|
|
int
|
|
__pthread_timedsuspend_new(pthread_descr self, const struct timespec *abstime)
|
|
{
|
|
sigset_t unblock, initial_mask;
|
|
int was_signalled = 0;
|
|
sigjmp_buf jmpbuf;
|
|
|
|
if (sigsetjmp(jmpbuf, 1) == 0) {
|
|
THREAD_SETMEM(self, p_signal_jmp, &jmpbuf);
|
|
THREAD_SETMEM(self, p_signal, 0);
|
|
/* Unblock the restart signal */
|
|
sigemptyset(&unblock);
|
|
sigaddset(&unblock, __pthread_sig_restart);
|
|
sigprocmask(SIG_UNBLOCK, &unblock, &initial_mask);
|
|
|
|
while (1) {
|
|
struct timeval now;
|
|
struct timespec reltime;
|
|
|
|
/* Compute a time offset relative to now. */
|
|
__gettimeofday (&now, NULL);
|
|
reltime.tv_nsec = abstime->tv_nsec - now.tv_usec * 1000;
|
|
reltime.tv_sec = abstime->tv_sec - now.tv_sec;
|
|
if (reltime.tv_nsec < 0) {
|
|
reltime.tv_nsec += 1000000000;
|
|
reltime.tv_sec -= 1;
|
|
}
|
|
|
|
/* Sleep for the required duration. If woken by a signal,
|
|
resume waiting as required by Single Unix Specification. */
|
|
if (reltime.tv_sec < 0 || __libc_nanosleep(&reltime, NULL) == 0)
|
|
break;
|
|
}
|
|
|
|
/* Block the restart signal again */
|
|
sigprocmask(SIG_SETMASK, &initial_mask, NULL);
|
|
was_signalled = 0;
|
|
} else {
|
|
was_signalled = 1;
|
|
}
|
|
THREAD_SETMEM(self, p_signal_jmp, NULL);
|
|
|
|
/* Now was_signalled is true if we exited the above code
|
|
due to the delivery of a restart signal. In that case,
|
|
everything is cool. We have been removed from whatever
|
|
we were waiting on by the other thread, and consumed its signal.
|
|
|
|
Otherwise we this thread woke up spontaneously, or due to a signal other
|
|
than restart. This is an ambiguous case that must be resolved by
|
|
the caller; the thread is still eligible for a restart wakeup
|
|
so there is a race. */
|
|
|
|
READ_MEMORY_BARRIER(); /* See comment in __pthread_restart_new */
|
|
return was_signalled;
|
|
}
|
|
|
|
|
|
/* Debugging aid */
|
|
|
|
#ifdef DEBUG
|
|
#include <stdarg.h>
|
|
|
|
void __pthread_message(const char * fmt, ...)
|
|
{
|
|
char buffer[1024];
|
|
va_list args;
|
|
sprintf(buffer, "%05d : ", __getpid());
|
|
va_start(args, fmt);
|
|
vsnprintf(buffer + 8, sizeof(buffer) - 8, fmt, args);
|
|
va_end(args);
|
|
TEMP_FAILURE_RETRY(__libc_write(2, buffer, strlen(buffer)));
|
|
}
|
|
|
|
#endif
|