freebsd-nq/lib/libpthread/thread/thr_init.c
Jason Evans 0a3fa43c7e Implement continuations to correctly handle [sig|_]longjmp() inside of a
signal handler.  Explicitly check for jumps to anywhere other than the
current stack, since such jumps are undefined according to POSIX.

While we're at it, convert thread cancellation to use continuations, since
it's cleaner than the original cancellation code.

Avoid delivering a signal to a thread twice.  This was a pre-existing bug,
but was likely unexposed until these other changes were made.

Defer signals generated by pthread_kill() so that they can be delivered on
the appropriate stack.  deischen claims that this is unnecessary, which is
likely true, but without this change, pthread_kill() can cause undefined
priority queue states and/or PANICs in [sig|_]longjmp(), so I'm leaving
this in for now.  To compile this code out and exercise the bug, define
the _NO_UNDISPATCH cpp macro.  Defining _PTHREADS_INVARIANTS as well will
cause earlier crashes.

PR:			kern/14685
Collaboration with:	deischen
2000-01-19 07:04:50 +00:00

391 lines
12 KiB
C

/*
* 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 <errno.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <paths.h>
#include <poll.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/sysctl.h>
#include <sys/time.h>
#include <sys/ttycom.h>
#include <sys/param.h>
#include <sys/user.h>
#include <sys/mman.h>
#ifdef _THREAD_SAFE
#include <machine/reg.h>
#include <pthread.h>
#include "pthread_private.h"
#ifdef GCC_2_8_MADE_THREAD_AWARE
typedef void *** (*dynamic_handler_allocator)();
extern void __set_dynamic_handler_allocator(dynamic_handler_allocator);
static pthread_key_t except_head_key;
typedef struct {
void **__dynamic_handler_chain;
void *top_elt[2];
} except_struct;
static void ***dynamic_allocator_handler_fn()
{
except_struct *dh = (except_struct *)pthread_getspecific(except_head_key);
if(dh == NULL) {
dh = (except_struct *)malloc( sizeof(except_struct) );
memset(dh, '\0', sizeof(except_struct));
dh->__dynamic_handler_chain= dh->top_elt;
pthread_setspecific(except_head_key, (void *)dh);
}
return &dh->__dynamic_handler_chain;
}
#endif /* GCC_2_8_MADE_THREAD_AWARE */
/*
* Threaded process initialization
*/
void
_thread_init(void)
{
int fd;
int flags;
int i;
size_t len;
int mib[2];
struct timeval tv;
struct clockinfo clockinfo;
struct sigaction act;
/* Check if this function has already been called: */
if (_thread_initial)
/* Only initialise the threaded application once. */
return;
/*
* 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 = _thread_sys_open(_PATH_CONSOLE, O_RDWR)) < 0)
PANIC("Can't open console");
if (setlogin("root") == -1)
PANIC("Can't set login to root");
if (_thread_sys_ioctl(fd,TIOCSCTTY, (char *) NULL) == -1)
PANIC("Can't set controlling terminal");
if (_thread_sys_dup2(fd,0) == -1 ||
_thread_sys_dup2(fd,1) == -1 ||
_thread_sys_dup2(fd,2) == -1)
PANIC("Can't dup2");
}
/* Get the standard I/O flags before messing with them : */
for (i = 0; i < 3; i++)
if (((_pthread_stdio_flags[i] =
_thread_sys_fcntl(i,F_GETFL, NULL)) == -1) &&
(errno != EBADF))
PANIC("Cannot get stdio flags");
/*
* Create a pipe that is written to by the signal handler to prevent
* signals being missed in calls to _select:
*/
if (_thread_sys_pipe(_thread_kern_pipe) != 0) {
/* Cannot create pipe, so abort: */
PANIC("Cannot create kernel pipe");
}
/* Get the flags for the read pipe: */
else if ((flags = _thread_sys_fcntl(_thread_kern_pipe[0], F_GETFL, NULL)) == -1) {
/* Abort this application: */
PANIC("Cannot get kernel read pipe flags");
}
/* Make the read pipe non-blocking: */
else if (_thread_sys_fcntl(_thread_kern_pipe[0], F_SETFL, flags | O_NONBLOCK) == -1) {
/* Abort this application: */
PANIC("Cannot make kernel read pipe non-blocking");
}
/* Get the flags for the write pipe: */
else if ((flags = _thread_sys_fcntl(_thread_kern_pipe[1], F_GETFL, NULL)) == -1) {
/* Abort this application: */
PANIC("Cannot get kernel write pipe flags");
}
/* Make the write pipe non-blocking: */
else if (_thread_sys_fcntl(_thread_kern_pipe[1], F_SETFL, flags | O_NONBLOCK) == -1) {
/* Abort this application: */
PANIC("Cannot get kernel write pipe flags");
}
/* Allocate and initialize the ready queue: */
else if (_pq_alloc(&_readyq, PTHREAD_MIN_PRIORITY, PTHREAD_MAX_PRIORITY) != 0) {
/* Abort this application: */
PANIC("Cannot allocate priority ready queue.");
}
/* Allocate memory for the thread structure of the initial thread: */
else if ((_thread_initial = (pthread_t) malloc(sizeof(struct pthread))) == NULL) {
/*
* Insufficient memory to initialise this application, so
* abort:
*/
PANIC("Cannot allocate memory for initial thread");
} else {
/* Zero the global kernel thread structure: */
memset(&_thread_kern_thread, 0, sizeof(struct pthread));
_thread_kern_thread.flags = PTHREAD_FLAGS_PRIVATE;
memset(_thread_initial, 0, sizeof(struct pthread));
/* Initialize the waiting and work queues: */
TAILQ_INIT(&_waitingq);
TAILQ_INIT(&_workq);
/* Initialize the scheduling switch hook routine: */
_sched_switch_hook = NULL;
/* Give this thread default attributes: */
memcpy((void *) &_thread_initial->attr, &pthread_attr_default,
sizeof(struct pthread_attr));
/* Initialize the thread stack cache: */
SLIST_INIT(&_stackq);
/*
* 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((void *) USRSTACK - PTHREAD_STACK_INITIAL -
PTHREAD_STACK_GUARD, PTHREAD_STACK_GUARD, 0, MAP_ANON,
-1, 0) == MAP_FAILED)
PANIC("Cannot allocate red zone for initial thread");
/* Set the main thread stack pointer. */
_thread_initial->stack = (void *) USRSTACK -
PTHREAD_STACK_INITIAL;
/* Set the stack attributes: */
_thread_initial->attr.stackaddr_attr = _thread_initial->stack;
_thread_initial->attr.stacksize_attr = PTHREAD_STACK_INITIAL;
/*
* Write a magic value to the thread structure
* to help identify valid ones:
*/
_thread_initial->magic = PTHREAD_MAGIC;
/* Set the initial cancel state */
_thread_initial->cancelflags = PTHREAD_CANCEL_ENABLE |
PTHREAD_CANCEL_DEFERRED;
/* Default the priority of the initial thread: */
_thread_initial->base_priority = PTHREAD_DEFAULT_PRIORITY;
_thread_initial->active_priority = PTHREAD_DEFAULT_PRIORITY;
_thread_initial->inherited_priority = 0;
/* Initialise the state of the initial thread: */
_thread_initial->state = PS_RUNNING;
/* Initialise the queue: */
TAILQ_INIT(&(_thread_initial->join_queue));
/* Initialize the owned mutex queue and count: */
TAILQ_INIT(&(_thread_initial->mutexq));
_thread_initial->priority_mutex_count = 0;
/* Initialize last active time to now: */
gettimeofday(&tv, NULL);
_thread_initial->last_active.tv_sec = tv.tv_sec;
_thread_initial->last_active.tv_usec = tv.tv_usec;
/* Initialise the rest of the fields: */
_thread_initial->poll_data.nfds = 0;
_thread_initial->poll_data.fds = NULL;
_thread_initial->sig_defer_count = 0;
_thread_initial->yield_on_sig_undefer = 0;
_thread_initial->specific_data = NULL;
_thread_initial->cleanup = NULL;
_thread_initial->flags = 0;
_thread_initial->error = 0;
TAILQ_INIT(&_thread_list);
TAILQ_INSERT_HEAD(&_thread_list, _thread_initial, tle);
_thread_run = _thread_initial;
/* Initialise the global signal action structure: */
sigfillset(&act.sa_mask);
act.sa_handler = (void (*) ()) _thread_sig_handler;
act.sa_flags = 0;
/* Initialize signal handling: */
_thread_sig_init();
/* Enter a loop to get the existing signal status: */
for (i = 1; i < NSIG; i++) {
/* Check for signals which cannot be trapped: */
if (i == SIGKILL || i == SIGSTOP) {
}
/* Get the signal handler details: */
else if (_thread_sys_sigaction(i, NULL,
&_thread_sigact[i - 1]) != 0) {
/*
* Abort this process if signal
* initialisation fails:
*/
PANIC("Cannot read signal handler info");
}
}
/*
* Install the signal handler for the most important
* signals that the user-thread kernel needs. Actually
* SIGINFO isn't really needed, but it is nice to have.
*/
if (_thread_sys_sigaction(_SCHED_SIGNAL, &act, NULL) != 0 ||
_thread_sys_sigaction(SIGINFO, &act, NULL) != 0 ||
_thread_sys_sigaction(SIGCHLD, &act, NULL) != 0) {
/*
* Abort this process if signal initialisation fails:
*/
PANIC("Cannot initialise signal handler");
}
/* Get the kernel clockrate: */
mib[0] = CTL_KERN;
mib[1] = KERN_CLOCKRATE;
len = sizeof (struct clockinfo);
if (sysctl(mib, 2, &clockinfo, &len, NULL, 0) == 0)
_clock_res_nsec = clockinfo.tick * 1000;
/* Get the table size: */
if ((_thread_dtablesize = getdtablesize()) < 0) {
/*
* Cannot get the system defined table size, so abort
* this process.
*/
PANIC("Cannot get dtablesize");
}
/* Allocate memory for the file descriptor table: */
if ((_thread_fd_table = (struct fd_table_entry **) malloc(sizeof(struct fd_table_entry *) * _thread_dtablesize)) == NULL) {
/* Avoid accesses to file descriptor table on exit: */
_thread_dtablesize = 0;
/*
* Cannot allocate memory for the file descriptor
* table, so abort this process.
*/
PANIC("Cannot allocate memory for file descriptor table");
}
/* Allocate memory for the pollfd table: */
if ((_thread_pfd_table = (struct pollfd *) malloc(sizeof(struct pollfd) * _thread_dtablesize)) == NULL) {
/*
* Cannot allocate memory for the file descriptor
* table, so abort this process.
*/
PANIC("Cannot allocate memory for pollfd table");
} else {
/*
* Enter a loop to initialise the file descriptor
* table:
*/
for (i = 0; i < _thread_dtablesize; i++) {
/* Initialise the file descriptor table: */
_thread_fd_table[i] = NULL;
}
/* Initialize stdio file descriptor table entries: */
for (i = 0; i < 3; i++) {
if ((_thread_fd_table_init(i) != 0) &&
(errno != EBADF))
PANIC("Cannot initialize stdio file "
"descriptor table entry");
}
}
}
#ifdef GCC_2_8_MADE_THREAD_AWARE
/* Create the thread-specific data for the exception linked list. */
if(pthread_key_create(&except_head_key, NULL) != 0)
PANIC("Failed to create thread specific execption head");
/* Setup the gcc exception handler per thread. */
__set_dynamic_handler_allocator( dynamic_allocator_handler_fn );
#endif /* GCC_2_8_MADE_THREAD_AWARE */
/* Initialise the garbage collector mutex and condition variable. */
if (pthread_mutex_init(&_gc_mutex,NULL) != 0 ||
pthread_cond_init(&_gc_cond,NULL) != 0)
PANIC("Failed to initialise garbage collector mutex or condvar");
gettimeofday(&kern_inc_prio_time, NULL);
return;
}
/*
* 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
#else
/*
* A stub for non-threaded programs.
*/
void
_thread_init(void)
{
}
#endif