freebsd-dev/lib/libthr/thread/thr_init.c

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/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/* Allocate space for global thread variables here: */
#define GLOBAL_PTHREAD_PRIVATE
#include "namespace.h"
#include <sys/param.h>
#include <sys/types.h>
#include <machine/reg.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <sys/event.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/ttycom.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "un-namespace.h"
#include "thr_private.h"
extern void _thread_init_hack(void);
/*
* All weak references used within libc should be in this table.
* This will is so that static libraries will work.
*
* XXXTHR - Check this list.
*/
static void *references[] = {
&_thread_init_hack,
&_thread_init,
&_accept,
&_bind,
&_close,
&_connect,
&_dup,
&_dup2,
&_execve,
&_fcntl,
&_flock,
&_flockfile,
&_fstat,
&_fstatfs,
&_fsync,
&_funlockfile,
&_getdirentries,
&_getlogin,
&_getpeername,
&_getsockname,
&_getsockopt,
&_ioctl,
&_kevent,
&_listen,
&_nanosleep,
&_open,
&_pthread_getspecific,
&_pthread_key_create,
&_pthread_key_delete,
&_pthread_mutex_destroy,
&_pthread_mutex_init,
&_pthread_mutex_lock,
&_pthread_mutex_trylock,
&_pthread_mutex_unlock,
&_pthread_mutexattr_init,
&_pthread_mutexattr_destroy,
&_pthread_mutexattr_settype,
&_pthread_once,
&_pthread_setspecific,
&_read,
&_readv,
&_recvfrom,
&_recvmsg,
&_select,
&_sendmsg,
&_sendto,
&_setsockopt,
&_sigaction,
&_sigprocmask,
&_sigsuspend,
&_socket,
&_socketpair,
&_wait4,
&_write,
&_writev
};
/*
* These are needed when linking statically. All references within
* libgcc (and in the future libc) to these routines are weak, but
* if they are not (strongly) referenced by the application or other
* libraries, then the actual functions will not be loaded.
*/
static void *libgcc_references[] = {
&_thread_init_hack,
&_thread_init,
&_pthread_once,
&_pthread_key_create,
&_pthread_key_delete,
&_pthread_getspecific,
&_pthread_setspecific,
&_pthread_mutex_init,
&_pthread_mutex_destroy,
&_pthread_mutex_lock,
&_pthread_mutex_trylock,
&_pthread_mutex_unlock
};
int _pthread_guard_default;
int _pthread_page_size;
int _pthread_stack_default;
int _pthread_stack_initial;
/*
* Initialize the current thread.
*/
void
init_td_common(struct pthread *td, struct pthread_attr *attrp, int reinit)
{
/*
* Some parts of a pthread are initialized only once.
*/
if (!reinit) {
memset(td, 0, sizeof(struct pthread));
Make libthr async-signal-safe without costly signal masking. The guidlines I followed are: Only 3 functions (pthread_cancel, pthread_setcancelstate, pthread_setcanceltype) are required to be async-signal-safe by POSIX. None of the rest of the pthread api is required to be async-signal-safe. This means that only the three mentioned functions are safe to use from inside signal handlers. However, there are certain system/libc calls that are cancellation points that a caller may call from within a signal handler, and since they are cancellation points calls have to be made into libthr to test for cancellation and exit the thread if necessary. So, the cancellation test and thread exit code paths must be async-signal-safe as well. A summary of the changes follows: o Almost all of the code paths that masked signals, as well as locking the pthread structure now lock only the pthread structure. o Signals are masked (and left that way) as soon as a thread enters pthread_exit(). o The active and dead threads locks now explicitly require that signals are masked. o Access to the isdead field of the pthread structure is protected by both the active and dead list locks for writing. Either one is sufficient for reading. o The thread state and type fields have been combined into one three-state switch to make it easier to read without requiring a lock. It doesn't need a lock for writing (and therefore for reading either) because only the current thread can write to it and it is an integer value. o The thread state field of the pthread structure has been eliminated. It was an unnecessary field that mostly duplicated the flags field, but required additional locking that would make a lot more code paths require signal masking. Any truly unique values (such as PS_DEAD) have been reborn as separate members of the pthread structure. o Since the mutex and condvar pthread functions are not async-signal-safe there is no need to muck about with the wait queues when handling a signal ... o ... which also removes the need for wrapping signal handlers and sigaction(2). o The condvar and mutex async-cancellation code had to be revised as a result of some of these changes, which resulted in semi-unrelated changes which would have been difficult to work on as a separate commit, so they are included as well. The only part of the changes I am worried about is related to locking for the pthread joining fields. But, I will take a closer look at them once this mega-patch is committed.
2004-05-20 12:06:16 +00:00
td->cancelmode = M_DEFERRED;
td->cancelstate = M_DEFERRED;
td->cancellation = CS_NULL;
memcpy(&td->attr, attrp, sizeof(struct pthread_attr));
td->magic = PTHREAD_MAGIC;
TAILQ_INIT(&td->mutexq);
td->base_priority = PTHREAD_DEFAULT_PRIORITY;
td->active_priority = PTHREAD_DEFAULT_PRIORITY;
td->inherited_priority = PTHREAD_MIN_PRIORITY;
} else {
memset(&td->join_status, 0, sizeof(struct join_status));
}
td->joiner = NULL;
td->error = 0;
td->flags = 0;
}
/*
* Initialize the active and dead threads list. Any threads in the active
* list will be removed and the thread td * will be marked as the
* initial thread and inserted in the list as the only thread. Any threads
* in the dead threads list will also be removed.
*/
void
init_tdlist(struct pthread *td, int reinit)
{
struct pthread *tdTemp, *tdTemp2;
_thread_initial = td;
td->name = strdup("_thread_initial");
/*
* If this is not the first initialization, remove any entries
* that may be in the list and deallocate their memory. Also
* destroy any global pthread primitives (they will be recreated).
*/
if (reinit) {
TAILQ_FOREACH_SAFE(tdTemp, &_thread_list, tle, tdTemp2) {
if (tdTemp != NULL && tdTemp != td) {
TAILQ_REMOVE(&_thread_list, tdTemp, tle);
free(tdTemp);
}
}
TAILQ_FOREACH_SAFE(tdTemp, &_dead_list, dle, tdTemp2) {
if (tdTemp != NULL) {
TAILQ_REMOVE(&_dead_list, tdTemp, dle);
free(tdTemp);
}
}
_pthread_mutex_destroy(&dead_list_lock);
} else {
TAILQ_INIT(&_thread_list);
TAILQ_INIT(&_dead_list);
/* Insert this thread as the first thread in the active list */
TAILQ_INSERT_HEAD(&_thread_list, td, tle);
}
/*
* Initialize the active thread list lock and the
* dead threads list lock.
*/
memset(&thread_list_lock, 0, sizeof(spinlock_t));
if (_pthread_mutex_init(&dead_list_lock,NULL) != 0)
PANIC("Failed to initialize garbage collector primitives");
}
/*
* Threaded process initialization
*/
void
_thread_init(void)
{
struct pthread *pthread;
int fd;
size_t len;
int mib[2];
int error;
/* Check if this function has already been called: */
if (_thread_initial)
/* Only initialise the threaded application once. */
return;
_pthread_page_size = getpagesize();
_pthread_guard_default = getpagesize();
if (sizeof(void *) == 8) {
_pthread_stack_default = PTHREAD_STACK64_DEFAULT;
_pthread_stack_initial = PTHREAD_STACK64_INITIAL;
}
else {
_pthread_stack_default = PTHREAD_STACK32_DEFAULT;
_pthread_stack_initial = PTHREAD_STACK32_INITIAL;
}
pthread_attr_default.guardsize_attr = _pthread_guard_default;
pthread_attr_default.stacksize_attr = _pthread_stack_default;
/*
* Make gcc quiescent about {,libgcc_}references not being
* referenced:
*/
if ((references[0] == NULL) || (libgcc_references[0] == NULL))
PANIC("Failed loading mandatory references in _thread_init");
/*
* Check for the special case of this process running as
* or in place of init as pid = 1:
*/
if (getpid() == 1) {
/*
* Setup a new session for this process which is
* assumed to be running as root.
*/
if (setsid() == -1)
PANIC("Can't set session ID");
if (revoke(_PATH_CONSOLE) != 0)
PANIC("Can't revoke console");
if ((fd = __sys_open(_PATH_CONSOLE, O_RDWR)) < 0)
PANIC("Can't open console");
if (setlogin("root") == -1)
PANIC("Can't set login to root");
if (__sys_ioctl(fd, TIOCSCTTY, (char *) NULL) == -1)
PANIC("Can't set controlling terminal");
if (__sys_dup2(fd, 0) == -1 ||
__sys_dup2(fd, 1) == -1 ||
__sys_dup2(fd, 2) == -1)
PANIC("Can't dup2");
}
/* Allocate memory for the thread structure of the initial thread: */
if ((pthread = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
/*
* Insufficient memory to initialise this application, so
* abort:
*/
PANIC("Cannot allocate memory for initial thread");
}
init_tdlist(pthread, 0);
init_td_common(pthread, &pthread_attr_default, 0);
pthread->arch_id = _set_curthread(NULL, pthread, &error);
/* Get our thread id. */
thr_self(&pthread->thr_id);
/* Find the stack top */
mib[0] = CTL_KERN;
mib[1] = KERN_USRSTACK;
len = sizeof (_usrstack);
if (sysctl(mib, 2, &_usrstack, &len, NULL, 0) == -1)
_usrstack = (void *)USRSTACK;
/*
* Create a red zone below the main stack. All other stacks are
* constrained to a maximum size by the paramters passed to
* mmap(), but this stack is only limited by resource limits, so
* this stack needs an explicitly mapped red zone to protect the
* thread stack that is just beyond.
*/
if (mmap(_usrstack - _pthread_stack_initial -
_pthread_guard_default, _pthread_guard_default, 0,
MAP_ANON, -1, 0) == MAP_FAILED)
PANIC("Cannot allocate red zone for initial thread");
/* Set the main thread stack pointer. */
pthread->stack = _usrstack - _pthread_stack_initial;
/* Set the stack attributes. */
pthread->attr.stackaddr_attr = pthread->stack;
pthread->attr.stacksize_attr = _pthread_stack_initial;
/* Setup the context for initial thread. */
getcontext(&pthread->ctx);
pthread->ctx.uc_stack.ss_sp = pthread->stack;
pthread->ctx.uc_stack.ss_size = _pthread_stack_initial;
/* Initialize the atfork list and mutex */
TAILQ_INIT(&_atfork_list);
_pthread_mutex_init(&_atfork_mutex, NULL);
}
/*
* Special start up code for NetBSD/Alpha
*/
#if defined(__NetBSD__) && defined(__alpha__)
int
main(int argc, char *argv[], char *env);
int
_thread_main(int argc, char *argv[], char *env)
{
_thread_init();
return (main(argc, argv, env));
}
#endif