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glibc/linuxthreads/internals.h
Ulrich Drepper 1d2fc9b3c5 Redesigned how cancellation unblocks a thread from internal cancellation points (sem_wait, pthread_join, pthread_cond_{wait,timedwait}). Cancellation won't eat a signal in any of these functions (*required* by POSIX and Single Unix Spec!). 
2000-01-03  Kaz Kylheku  <kaz@ashi.footprints.net>

	Redesigned how cancellation unblocks a thread from internal
	cancellation points (sem_wait, pthread_join,
	pthread_cond_{wait,timedwait}).
	Cancellation won't eat a signal in any of these functions
	(*required* by POSIX and Single Unix Spec!).
	* condvar.c: spontaneous wakeup on pthread_cond_timedwait won't eat a
	simultaneous condition variable signal (not required by POSIX
	or Single Unix Spec, but nice).
	* spinlock.c: __pthread_lock queues back any received restarts
	that don't belong to it instead of assuming ownership of lock
	upon any restart; fastlock can no longer be acquired by two threads
	simultaneously.
	* restart.h: restarts queue even on kernels that don't have
	queued real time signals (2.0, early 2.1), thanks to atomic counter,
	avoiding a rare race condition in pthread_cond_timedwait.
2000-01-05 02:09:12 +00:00

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/* Linuxthreads - a simple clone()-based implementation of Posix */
/* threads for Linux. */
/* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr) */
/* */
/* This program is free software; you can redistribute it and/or */
/* modify it under the terms of the GNU Library General Public License */
/* as published by the Free Software Foundation; either version 2 */
/* of the License, or (at your option) any later version. */
/* */
/* This program is distributed in the hope that it will be useful, */
/* but WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the */
/* GNU Library General Public License for more details. */
#ifndef _INTERNALS_H
#define _INTERNALS_H 1
/* Internal data structures */
/* Includes */
#include <limits.h>
#include <setjmp.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <bits/libc-tsd.h> /* for _LIBC_TSD_KEY_N */
#include <resolv.h> /* for per-thread resolver context */
#include "pt-machine.h"
#include "semaphore.h"
#include "../linuxthreads_db/thread_dbP.h"
#ifndef THREAD_GETMEM
# define THREAD_GETMEM(descr, member) descr->member
#endif
#ifndef THREAD_GETMEM_NC
# define THREAD_GETMEM_NC(descr, member) descr->member
#endif
#ifndef THREAD_SETMEM
# define THREAD_SETMEM(descr, member, value) descr->member = (value)
#endif
#ifndef THREAD_SETMEM_NC
# define THREAD_SETMEM_NC(descr, member, value) descr->member = (value)
#endif
/* Arguments passed to thread creation routine */
struct pthread_start_args {
void * (*start_routine)(void *); /* function to run */
void * arg; /* its argument */
sigset_t mask; /* initial signal mask for thread */
int schedpolicy; /* initial scheduling policy (if any) */
struct sched_param schedparam; /* initial scheduling parameters (if any) */
};
/* We keep thread specific data in a special data structure, a two-level
array. The top-level array contains pointers to dynamically allocated
arrays of a certain number of data pointers. So we can implement a
sparse array. Each dynamic second-level array has
PTHREAD_KEY_2NDLEVEL_SIZE
entries. This value shouldn't be too large. */
#define PTHREAD_KEY_2NDLEVEL_SIZE 32
/* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
keys in each subarray. */
#define PTHREAD_KEY_1STLEVEL_SIZE \
((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
/ PTHREAD_KEY_2NDLEVEL_SIZE)
typedef void (*destr_function)(void *);
struct pthread_key_struct {
int in_use; /* already allocated? */
destr_function destr; /* destruction routine */
};
#define PTHREAD_START_ARGS_INITIALIZER(fct) \
{ (void *(*) (void *)) fct, NULL, {{0, }}, 0, { 0 } }
/* The type of thread descriptors */
typedef struct _pthread_descr_struct * pthread_descr;
/* Callback interface for removing the thread from waiting on an
object if it is cancelled while waiting or about to wait.
This hold a pointer to the object, and a pointer to a function
which ``extricates'' the thread from its enqueued state.
The function takes two arguments: pointer to the wait object,
and a pointer to the thread. It returns 1 if an extrication
actually occured, and hence the thread must also be signalled.
It returns 0 if the thread had already been extricated. */
typedef struct _pthread_extricate_struct {
void *pu_object;
int (*pu_extricate_func)(void *, pthread_descr);
} pthread_extricate_if;
/* Atomic counter made possible by compare_and_swap */
struct pthread_atomic {
long p_count;
int p_spinlock;
};
struct _pthread_descr_struct {
pthread_descr p_nextlive, p_prevlive;
/* Double chaining of active threads */
pthread_descr p_nextwaiting; /* Next element in the queue holding the thr */
pthread_descr p_nextlock; /* can be on a queue and waiting on a lock */
pthread_t p_tid; /* Thread identifier */
int p_pid; /* PID of Unix process */
int p_priority; /* Thread priority (== 0 if not realtime) */
struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
int p_signal; /* last signal received */
struct pthread_atomic p_resume_count; /* number of times restart() was called on thread */
sigjmp_buf * p_signal_jmp; /* where to siglongjmp on a signal or NULL */
sigjmp_buf * p_cancel_jmp; /* where to siglongjmp on a cancel or NULL */
char p_terminated; /* true if terminated e.g. by pthread_exit */
char p_detached; /* true if detached */
char p_exited; /* true if the assoc. process terminated */
void * p_retval; /* placeholder for return value */
int p_retcode; /* placeholder for return code */
pthread_descr p_joining; /* thread joining on that thread or NULL */
struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
char p_cancelstate; /* cancellation state */
char p_canceltype; /* cancellation type (deferred/async) */
char p_canceled; /* cancellation request pending */
char p_woken_by_cancel; /* cancellation performed wakeup */
pthread_extricate_if *p_extricate; /* See above */
int * p_errnop; /* pointer to used errno variable */
int p_errno; /* error returned by last system call */
int * p_h_errnop; /* pointer to used h_errno variable */
int p_h_errno; /* error returned by last netdb function */
char * p_in_sighandler; /* stack address of sighandler, or NULL */
char p_sigwaiting; /* true if a sigwait() is in progress */
struct pthread_start_args p_start_args; /* arguments for thread creation */
void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
int p_userstack; /* nonzero if the user provided the stack */
void *p_guardaddr; /* address of guard area or NULL */
size_t p_guardsize; /* size of guard area */
pthread_descr p_self; /* Pointer to this structure */
int p_nr; /* Index of descriptor in __pthread_handles */
int p_report_events; /* Nonzero if events must be reported. */
td_eventbuf_t p_eventbuf; /* Data for event. */
struct __res_state *p_resp; /* Pointer to resolver state */
struct __res_state p_res; /* per-thread resolver state */
/* New elements must be added at the end. */
} __attribute__ ((aligned(32))); /* We need to align the structure so that
doubles are aligned properly. This is 8
bytes on MIPS and 16 bytes on MIPS64.
32 bytes might give better cache
utilization. */
/* The type of thread handles. */
typedef struct pthread_handle_struct * pthread_handle;
struct pthread_handle_struct {
struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */
pthread_descr h_descr; /* Thread descriptor or NULL if invalid */
char * h_bottom; /* Lowest address in the stack thread */
};
/* The type of messages sent to the thread manager thread */
struct pthread_request {
pthread_descr req_thread; /* Thread doing the request */
enum { /* Request kind */
REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT,
REQ_POST, REQ_DEBUG
} req_kind;
union { /* Arguments for request */
struct { /* For REQ_CREATE: */
const pthread_attr_t * attr; /* thread attributes */
void * (*fn)(void *); /* start function */
void * arg; /* argument to start function */
sigset_t mask; /* signal mask */
} create;
struct { /* For REQ_FREE: */
pthread_t thread_id; /* identifier of thread to free */
} free;
struct { /* For REQ_PROCESS_EXIT: */
int code; /* exit status */
} exit;
void * post; /* For REQ_POST: the semaphore */
} req_args;
};
/* Signals used for suspend/restart and for cancellation notification. */
extern int __pthread_sig_restart;
extern int __pthread_sig_cancel;
/* Signal used for interfacing with gdb */
extern int __pthread_sig_debug;
/* Global array of thread handles, used for validating a thread id
and retrieving the corresponding thread descriptor. Also used for
mapping the available stack segments. */
extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX];
/* Descriptor of the initial thread */
extern struct _pthread_descr_struct __pthread_initial_thread;
/* Descriptor of the manager thread */
extern struct _pthread_descr_struct __pthread_manager_thread;
/* Descriptor of the main thread */
extern pthread_descr __pthread_main_thread;
/* Limit between the stack of the initial thread (above) and the
stacks of other threads (below). Aligned on a STACK_SIZE boundary.
Initially 0, meaning that the current thread is (by definition)
the initial thread. */
extern char *__pthread_initial_thread_bos;
/* Indicate whether at least one thread has a user-defined stack (if 1),
or all threads have stacks supplied by LinuxThreads (if 0). */
extern int __pthread_nonstandard_stacks;
/* File descriptor for sending requests to the thread manager.
Initially -1, meaning that __pthread_initialize_manager must be called. */
extern int __pthread_manager_request;
/* Other end of the pipe for sending requests to the thread manager. */
extern int __pthread_manager_reader;
/* Limits of the thread manager stack. */
extern char *__pthread_manager_thread_bos;
extern char *__pthread_manager_thread_tos;
/* Pending request for a process-wide exit */
extern int __pthread_exit_requested, __pthread_exit_code;
/* Set to 1 by gdb if we're debugging */
extern volatile int __pthread_threads_debug;
/* Globally enabled events. */
extern volatile td_thr_events_t __pthread_threads_events;
/* Pointer to descriptor of thread with last event. */
extern volatile pthread_descr __pthread_last_event;
/* Return the handle corresponding to a thread id */
static inline pthread_handle thread_handle(pthread_t id)
{
return &__pthread_handles[id % PTHREAD_THREADS_MAX];
}
/* Validate a thread handle. Must have acquired h->h_spinlock before. */
static inline int invalid_handle(pthread_handle h, pthread_t id)
{
return h->h_descr == NULL || h->h_descr->p_tid != id;
}
/* Fill in defaults left unspecified by pt-machine.h. */
/* The page size we can get from the system. This should likely not be
changed by the machine file but, you never know. */
#ifndef PAGE_SIZE
#define PAGE_SIZE (sysconf (_SC_PAGE_SIZE))
#endif
/* The max size of the thread stack segments. If the default
THREAD_SELF implementation is used, this must be a power of two and
a multiple of PAGE_SIZE. */
#ifndef STACK_SIZE
#define STACK_SIZE (2 * 1024 * 1024)
#endif
/* The initial size of the thread stack. Must be a multiple of PAGE_SIZE. */
#ifndef INITIAL_STACK_SIZE
#define INITIAL_STACK_SIZE (4 * PAGE_SIZE)
#endif
/* Size of the thread manager stack. The "- 32" avoids wasting space
with some malloc() implementations. */
#ifndef THREAD_MANAGER_STACK_SIZE
#define THREAD_MANAGER_STACK_SIZE (2 * PAGE_SIZE - 32)
#endif
/* The base of the "array" of thread stacks. The array will grow down from
here. Defaults to the calculated bottom of the initial application
stack. */
#ifndef THREAD_STACK_START_ADDRESS
#define THREAD_STACK_START_ADDRESS __pthread_initial_thread_bos
#endif
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */
#ifndef CURRENT_STACK_FRAME
#define CURRENT_STACK_FRAME ({ char __csf; &__csf; })
#endif
/* Recover thread descriptor for the current thread */
extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
static inline pthread_descr thread_self (void) __attribute__ ((const));
static inline pthread_descr thread_self (void)
{
#ifdef THREAD_SELF
return THREAD_SELF;
#else
char *sp = CURRENT_STACK_FRAME;
if (sp >= __pthread_initial_thread_bos)
return &__pthread_initial_thread;
else if (sp >= __pthread_manager_thread_bos
&& sp < __pthread_manager_thread_tos)
return &__pthread_manager_thread;
else if (__pthread_nonstandard_stacks)
return __pthread_find_self();
else
return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
#endif
}
/* Max number of times we must spin on a spinlock calling sched_yield().
After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
#ifndef MAX_SPIN_COUNT
#define MAX_SPIN_COUNT 50
#endif
/* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
after MAX_SPIN_COUNT iterations of sched_yield().
With the 2.0 and 2.1 kernels, this MUST BE > 2ms.
(Otherwise the kernel does busy-waiting for realtime threads,
giving other threads no chance to run.) */
#ifndef SPIN_SLEEP_DURATION
#define SPIN_SLEEP_DURATION 2000001
#endif
/* Debugging */
#ifdef DEBUG
#include <assert.h>
#define ASSERT assert
#define MSG __pthread_message
#else
#define ASSERT(x)
#define MSG(msg,arg...)
#endif
/* Internal global functions */
void __pthread_destroy_specifics(void);
void __pthread_perform_cleanup(void);
int __pthread_initialize_manager(void);
void __pthread_message(char * fmt, ...);
int __pthread_manager(void *reqfd);
int __pthread_manager_event(void *reqfd);
void __pthread_manager_sighandler(int sig);
void __pthread_reset_main_thread(void);
void __fresetlockfiles(void);
void __pthread_manager_adjust_prio(int thread_prio);
void __pthread_set_own_extricate_if(pthread_descr self, pthread_extricate_if *peif);
extern int __pthread_attr_setguardsize (pthread_attr_t *__attr,
size_t __guardsize);
extern int __pthread_attr_getguardsize (const pthread_attr_t *__attr,
size_t *__guardsize);
extern int __pthread_attr_setstackaddr (pthread_attr_t *__attr,
void *__stackaddr);
extern int __pthread_attr_getstackaddr (const pthread_attr_t *__attr,
void **__stackaddr);
extern int __pthread_attr_setstacksize (pthread_attr_t *__attr,
size_t __stacksize);
extern int __pthread_attr_getstacksize (const pthread_attr_t *__attr,
size_t *__stacksize);
extern int __pthread_getconcurrency (void);
extern int __pthread_setconcurrency (int __level);
extern int __pthread_mutexattr_gettype (const pthread_mutexattr_t *__attr,
int *__kind);
extern void __pthread_kill_other_threads_np (void);
void __pthread_restart_old(pthread_descr th);
void __pthread_suspend_old(pthread_descr self);
void __pthread_restart_new(pthread_descr th);
void __pthread_suspend_new(pthread_descr self);
void __pthread_wait_for_restart_signal(pthread_descr self);
void __pthread_init_condvar(int rt_sig_available);
/* Global pointers to old or new suspend functions */
extern void (*__pthread_restart)(pthread_descr);
extern void (*__pthread_suspend)(pthread_descr);
/* Prototypes for the function without cancelation support when the
normal version has it. */
extern int __libc_close (int fd);
extern int __libc_nanosleep (const struct timespec *requested_time,
struct timespec *remaining);
extern pid_t __libc_waitpid (pid_t pid, int *stat_loc, int options);
/* Prototypes for some of the new semaphore functions. */
extern int __new_sem_post (sem_t * sem);
/* The functions called the signal events. */
extern void __linuxthreads_create_event (void);
extern void __linuxthreads_death_event (void);
extern void __linuxthreads_reap_event (void);
#endif /* internals.h */
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