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48fc3dd224
1998-03-17 00:06 Ulrich Drepper <drepper@cygnus.com> * manager.c: Fix last patch which caused core dumps. * pthread.c: Correctly handle missing SIGRTMIN.
494 lines
17 KiB
C
494 lines
17 KiB
C
/* 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 <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 "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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/* Descriptor of the initial thread */
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struct _pthread_descr_struct __pthread_initial_thread = {
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&__pthread_initial_thread, /* pthread_descr p_nextlive */
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&__pthread_initial_thread, /* pthread_descr p_prevlive */
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NULL, /* pthread_descr p_nextwaiting */
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PTHREAD_THREADS_MAX, /* pthread_t p_tid */
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0, /* int p_pid */
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0, /* int p_priority */
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&__pthread_handles[0].h_spinlock, /* int * p_spinlock */
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0, /* int p_signal */
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NULL, /* sigjmp_buf * p_signal_buf */
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NULL, /* sigjmp_buf * p_cancel_buf */
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0, /* char p_terminated */
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0, /* char p_detached */
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0, /* char p_exited */
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NULL, /* void * p_retval */
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0, /* int p_retval */
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NULL, /* pthread_descr p_joining */
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NULL, /* struct _pthread_cleanup_buffer * p_cleanup */
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0, /* char p_cancelstate */
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0, /* char p_canceltype */
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0, /* char p_canceled */
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NULL, /* int *p_errnop */
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0, /* int p_errno */
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NULL, /* int *p_h_errnop */
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0, /* int p_h_errno */
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PTHREAD_START_ARGS_INITIALIZER, /* struct pthread_start_args p_start_args */
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{NULL} /* void * p_specific[PTHREAD_KEYS_MAX] */
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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 and the address for identification. */
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struct _pthread_descr_struct __pthread_manager_thread = {
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NULL, /* pthread_descr p_nextlive */
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NULL, /* pthread_descr p_prevlive */
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NULL, /* pthread_descr p_nextwaiting */
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0, /* int p_tid */
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0, /* int p_pid */
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0, /* int p_priority */
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NULL, /* int * p_spinlock */
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0, /* int p_signal */
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NULL, /* sigjmp_buf * p_signal_buf */
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NULL, /* sigjmp_buf * p_cancel_buf */
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0, /* char p_terminated */
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0, /* char p_detached */
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0, /* char p_exited */
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NULL, /* void * p_retval */
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0, /* int p_retval */
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NULL, /* pthread_descr p_joining */
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NULL, /* struct _pthread_cleanup_buffer * p_cleanup */
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0, /* char p_cancelstate */
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0, /* char p_canceltype */
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0, /* char p_canceled */
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NULL, /* int *p_errnop */
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0, /* int p_errno */
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NULL, /* int *p_h_errnop */
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0, /* int p_h_errno */
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PTHREAD_START_ARGS_INITIALIZER, /* struct pthread_start_args p_start_args */
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{NULL} /* void * p_specific[PTHREAD_KEYS_MAX] */
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};
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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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pthread_descr __pthread_main_thread = &__pthread_initial_thread;
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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 = NULL;
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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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/* Other end of the pipe for sending requests to the thread manager. */
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int __pthread_manager_reader;
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/* PID of thread manager */
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static int __pthread_manager_pid;
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/* Limits of the thread manager stack */
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char *__pthread_manager_thread_bos = NULL;
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char *__pthread_manager_thread_tos = NULL;
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/* For process-wide exit() */
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int __pthread_exit_requested = 0;
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int __pthread_exit_code = 0;
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/* Signal numbers used for the communication. */
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int __pthread_sig_restart;
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int __pthread_sig_cancel;
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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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/* Forward declarations */
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static void pthread_exit_process(int retcode, void *arg);
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static void pthread_handle_sigcancel(int sig);
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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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static void pthread_initialize(void)
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{
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struct sigaction sa;
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sigset_t mask;
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/* If already done (e.g. by a constructor called earlier!), bail out */
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if (__pthread_initial_thread_bos != NULL) return;
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/* For the initial stack, reserve at least STACK_SIZE bytes of stack
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below the current stack address, and align that on a
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STACK_SIZE boundary. */
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__pthread_initial_thread_bos =
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(char *)(((long)CURRENT_STACK_FRAME - 2 * STACK_SIZE) & ~(STACK_SIZE - 1));
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/* Update the descriptor for the initial thread. */
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__pthread_initial_thread.p_pid = __getpid();
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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);
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#endif
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/* The errno/h_errno variable of the main thread are the global ones. */
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__pthread_initial_thread.p_errnop = &_errno;
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__pthread_initial_thread.p_h_errnop = &_h_errno;
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#ifdef SIGRTMIN
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/* Allocate the signals used. */
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__pthread_sig_restart = __libc_allocate_rtsig (1);
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__pthread_sig_cancel = __libc_allocate_rtsig (1);
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if (__pthread_sig_restart < 0 || __pthread_sig_cancel < 0)
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{
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/* The kernel does not support real-time signals. Use as before
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the available signals in the fixed set. */
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__pthread_sig_restart = SIGUSR1;
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__pthread_sig_cancel = SIGUSR2;
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}
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#endif
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/* Setup signal handlers for the initial thread.
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Since signal handlers are shared between threads, these settings
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will be inherited by all other threads. */
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sa.sa_handler = __pthread_sighandler;
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sigemptyset(&sa.sa_mask);
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sa.sa_flags = SA_RESTART; /* does not matter for regular threads, but
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better for the thread manager */
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sigaction(PTHREAD_SIG_RESTART, &sa, NULL);
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sa.sa_handler = pthread_handle_sigcancel;
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sa.sa_flags = 0;
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sigaction(PTHREAD_SIG_CANCEL, &sa, NULL);
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/* Initially, block PTHREAD_SIG_RESTART. Will be unblocked on demand. */
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sigemptyset(&mask);
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sigaddset(&mask, PTHREAD_SIG_RESTART);
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sigprocmask(SIG_BLOCK, &mask, NULL);
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/* Register an exit function to kill all other threads. */
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/* Do it early so that user-registered atexit functions are called
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before pthread_exit_process. */
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__on_exit(pthread_exit_process, NULL);
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}
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static int pthread_initialize_manager(void)
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{
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int manager_pipe[2];
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/* If basic initialization not done yet (e.g. we're called from a
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constructor run before our constructor), do it now */
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if (__pthread_initial_thread_bos == NULL) pthread_initialize();
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/* Setup stack for thread manager */
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__pthread_manager_thread_bos = malloc(THREAD_MANAGER_STACK_SIZE);
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if (__pthread_manager_thread_bos == NULL) return -1;
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__pthread_manager_thread_tos =
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__pthread_manager_thread_bos + THREAD_MANAGER_STACK_SIZE;
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/* Setup pipe to communicate with thread manager */
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if (pipe(manager_pipe) == -1) {
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free(__pthread_manager_thread_bos);
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return -1;
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}
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__pthread_manager_request = manager_pipe[1]; /* writing end */
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__pthread_manager_reader = manager_pipe[0]; /* reading end */
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/* Start the thread manager */
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__pthread_manager_pid =
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__clone(__pthread_manager, (void **) __pthread_manager_thread_tos,
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CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND,
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(void *)(long)manager_pipe[0]);
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if (__pthread_manager_pid == -1) {
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free(__pthread_manager_thread_bos);
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__libc_close(manager_pipe[0]);
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__libc_close(manager_pipe[1]);
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__pthread_manager_request = -1;
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return -1;
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}
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return 0;
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}
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/* Thread creation */
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int __pthread_create_2_1(pthread_t *thread, const pthread_attr_t *attr,
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void * (*start_routine)(void *), void *arg)
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{
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pthread_descr self = thread_self();
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struct pthread_request request;
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if (__pthread_manager_request < 0) {
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if (pthread_initialize_manager() < 0) return EAGAIN;
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}
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request.req_thread = self;
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request.req_kind = REQ_CREATE;
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request.req_args.create.attr = attr;
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request.req_args.create.fn = start_routine;
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request.req_args.create.arg = arg;
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sigprocmask(SIG_SETMASK, (const sigset_t *) NULL,
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&request.req_args.create.mask);
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__libc_write(__pthread_manager_request, (char *) &request, sizeof(request));
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suspend(self);
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if (self->p_retcode == 0) *thread = (pthread_t) self->p_retval;
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return self->p_retcode;
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}
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#if defined HAVE_ELF && defined PIC && defined DO_VERSIONING
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default_symbol_version (__pthread_create_2_1, pthread_create, GLIBC_2.1);
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int __pthread_create_2_0(pthread_t *thread, const pthread_attr_t *attr,
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void * (*start_routine)(void *), void *arg)
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{
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/* The ATTR attribute is not really of type `pthread_attr_t *'. It has
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the old size and access to the new members might crash the program.
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We convert the struct now. */
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pthread_attr_t new_attr;
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if (attr != NULL)
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{
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size_t ps = __getpagesize ();
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memcpy (&new_attr, attr, (size_t) &(((pthread_attr_t*)NULL)->guardsize));
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new_attr.guardsize = ps;
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new_attr.stackaddr_set = 0;
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new_attr.stackaddr = NULL;
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new_attr.stacksize = STACK_SIZE - ps;
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attr = &new_attr;
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}
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return __pthread_create_2_1 (thread, attr, start_routine, arg);
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}
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symbol_version (__pthread_create_2_0, pthread_create, GLIBC_2.0);
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#else
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strong_alias (__pthread_create_2_1, pthread_create)
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#endif
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/* Simple operations on thread identifiers */
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pthread_t pthread_self(void)
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{
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pthread_descr self = thread_self();
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return self->p_tid;
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}
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int pthread_equal(pthread_t thread1, pthread_t thread2)
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{
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return thread1 == thread2;
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}
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/* Thread scheduling */
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int pthread_setschedparam(pthread_t thread, int policy,
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const struct sched_param *param)
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{
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pthread_handle handle = thread_handle(thread);
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pthread_descr th;
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acquire(&handle->h_spinlock);
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if (invalid_handle(handle, thread)) {
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release(&handle->h_spinlock);
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return ESRCH;
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}
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th = handle->h_descr;
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if (__sched_setscheduler(th->p_pid, policy, param) == -1) {
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release(&handle->h_spinlock);
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return errno;
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}
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th->p_priority = policy == SCHED_OTHER ? 0 : param->sched_priority;
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release(&handle->h_spinlock);
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return 0;
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}
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int pthread_getschedparam(pthread_t thread, int *policy,
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struct sched_param *param)
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{
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pthread_handle handle = thread_handle(thread);
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int pid, pol;
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acquire(&handle->h_spinlock);
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if (invalid_handle(handle, thread)) {
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release(&handle->h_spinlock);
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return ESRCH;
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}
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pid = handle->h_descr->p_pid;
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release(&handle->h_spinlock);
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pol = __sched_getscheduler(pid);
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if (pol == -1) return errno;
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if (__sched_getparam(pid, param) == -1) return errno;
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*policy = pol;
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return 0;
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}
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/* Process-wide exit() request */
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static void pthread_exit_process(int retcode, void *arg)
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{
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struct pthread_request request;
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pthread_descr self = thread_self();
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if (__pthread_manager_request >= 0) {
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request.req_thread = self;
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request.req_kind = REQ_PROCESS_EXIT;
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request.req_args.exit.code = retcode;
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__libc_write(__pthread_manager_request,
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(char *) &request, sizeof(request));
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suspend(self);
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/* Main thread should accumulate times for thread manager and its
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children, so that timings for main thread account for all threads. */
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if (self == __pthread_main_thread)
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waitpid(__pthread_manager_pid, NULL, __WCLONE);
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}
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}
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/* The handler for the RESTART signal just records the signal received
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in the thread descriptor, and optionally performs a siglongjmp
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(for pthread_cond_timedwait). Also used in sigwait.
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For the thread manager thread, redirect the signal to
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__pthread_manager_sighandler. */
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void __pthread_sighandler(int sig)
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{
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pthread_descr self = thread_self();
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if (self == &__pthread_manager_thread) {
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__pthread_manager_sighandler(sig);
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} else {
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self->p_signal = sig;
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if (self->p_signal_jmp != NULL) siglongjmp(*self->p_signal_jmp, 1);
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}
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}
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/* The handler for the CANCEL signal checks for cancellation
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(in asynchronous mode) and for process-wide exit and exec requests. */
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static void pthread_handle_sigcancel(int sig)
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{
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pthread_descr self = thread_self();
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sigjmp_buf * jmpbuf;
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if (__pthread_exit_requested) {
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/* Main thread should accumulate times for thread manager and its
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children, so that timings for main thread account for all threads. */
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if (self == __pthread_main_thread)
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waitpid(__pthread_manager_pid, NULL, __WCLONE);
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_exit(__pthread_exit_code);
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}
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if (self->p_canceled && self->p_cancelstate == PTHREAD_CANCEL_ENABLE) {
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if (self->p_canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
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pthread_exit(PTHREAD_CANCELED);
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jmpbuf = self->p_cancel_jmp;
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if (jmpbuf != NULL) {
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self->p_cancel_jmp = NULL;
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siglongjmp(*jmpbuf, 1);
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}
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}
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}
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/* Reset the state of the thread machinery after a fork().
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Close the pipe used for requests and set the main thread to the forked
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thread.
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Notice that we can't free the stack segments, as the forked thread
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may hold pointers into them. */
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void __pthread_reset_main_thread()
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{
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pthread_descr self = thread_self();
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if (__pthread_manager_request != -1) {
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/* Free the thread manager stack */
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free(__pthread_manager_thread_bos);
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__pthread_manager_thread_bos = __pthread_manager_thread_tos = NULL;
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/* Close the two ends of the pipe */
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__libc_close(__pthread_manager_request);
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__libc_close(__pthread_manager_reader);
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__pthread_manager_request = __pthread_manager_reader = -1;
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}
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/* Update the pid of the main thread */
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self->p_pid = __getpid();
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/* Make the forked thread the main thread */
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__pthread_main_thread = self;
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self->p_nextlive = self;
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self->p_prevlive = self;
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/* Now this thread modifies the global variables. */
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self->p_errnop = &_errno;
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self->p_h_errnop = &_h_errno;
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}
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/* Process-wide exec() request */
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void __pthread_kill_other_threads_np(void)
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{
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/* Terminate all other threads and thread manager */
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pthread_exit_process(0, NULL);
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/* Make current thread the main thread in case the calling thread
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changes its mind, does not exec(), and creates new threads instead. */
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__pthread_reset_main_thread();
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}
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weak_alias (__pthread_kill_other_threads_np, pthread_kill_other_threads_np)
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/* Concurrency symbol level. */
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static int current_level;
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int __pthread_setconcurrency(int level)
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{
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/* We don't do anything unless we have found a useful interpretation. */
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current_level = level;
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return 0;
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}
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weak_alias (__pthread_setconcurrency, pthread_setconcurrency)
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int __pthread_getconcurrency(void)
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{
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return current_level;
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}
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weak_alias (__pthread_getconcurrency, pthread_getconcurrency)
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/* Debugging aid */
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#ifdef DEBUG
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#include <stdarg.h>
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void __pthread_message(char * fmt, long arg)
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{
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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);
|
|
__libc_write(2, buffer, strlen(buffer));
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
#ifndef PIC
|
|
/* We need a hook to force the cancelation wrappers to be linked in when
|
|
static libpthread is used. */
|
|
extern const int __pthread_provide_wrappers;
|
|
static const int *const __pthread_require_wrappers =
|
|
&__pthread_provide_wrappers;
|
|
#endif
|