glibc/linuxthreads/internals.h

/* 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 */

#define __RES_PTHREAD_INTERNAL
#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;
};

/* Context info for read write locks. The pthread_rwlock_info structure
   is information about a lock that has been read-locked by the thread
   in whose list this structure appears. The pthread_rwlock_context
   is embedded in the thread context and contains a pointer to the
   head of the list of lock info structures, as well as a count of
   read locks that are untracked, because no info structure could be
   allocated for them. */

struct _pthread_rwlock_t;

typedef struct _pthread_rwlock_info {
  struct _pthread_rwlock_info *pr_next;
  struct _pthread_rwlock_t *pr_lock;
  int pr_lock_count;
} pthread_readlock_info;

struct _pthread_descr_struct {
  union {
    struct {
      pthread_descr self;	/* Pointer to this structure */
    } data;
    void *__padding[16];
  } p_header;
  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 */
  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 */
  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 */
  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 pthread_atomic p_resume_count; /* number of times restart() was
					   called on thread */
  char p_woken_by_cancel;       /* cancellation performed wakeup */
  pthread_extricate_if *p_extricate; /* See above */
  pthread_readlock_info *p_readlock_list;  /* List of readlock info structs */
  pthread_readlock_info *p_readlock_free;  /* Free list of structs */
  int p_untracked_readlock_count;	/* Readlocks not tracked by list */
  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_KICK
  } 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;

/* Flag which tells whether we are executing on SMP kernel. */
extern int __pthread_smp_kernel;

/* 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 || h->h_descr->p_terminated;
}

static inline int nonexisting_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.  */

/* We round up a value with page size. */
#ifndef page_roundup
#define page_roundup(v,p) ((((size_t) (v)) + (p) - 1) & ~((p) - 1))
#endif

/* 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
}

/* If MEMORY_BARRIER isn't defined in pt-machine.h, assume the architecture
   doesn't need a memory barrier instruction (e.g. Intel x86).  Some
   architectures distinguish between full, read and write barriers.  */

#ifndef MEMORY_BARRIER
#define MEMORY_BARRIER()
#endif
#ifndef READ_MEMORY_BARRIER
#define READ_MEMORY_BARRIER() MEMORY_BARRIER()
#endif
#ifndef WRITE_MEMORY_BARRIER
#define WRITE_MEMORY_BARRIER() MEMORY_BARRIER()
#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 __pthread_once_fork_prepare(void);
void __pthread_once_fork_parent(void);
void __pthread_once_fork_child(void);
void __flockfilelist(void);
void __funlockfilelist(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);
int __pthread_timedsuspend_old(pthread_descr self, const struct timespec *abs);

void __pthread_restart_new(pthread_descr th);
void __pthread_suspend_new(pthread_descr self);
int __pthread_timedsuspend_new(pthread_descr self, const struct timespec *abs);

void __pthread_wait_for_restart_signal(pthread_descr self);

int __pthread_yield (void);

/* Global pointers to old or new suspend functions */

extern void (*__pthread_restart)(pthread_descr);
extern void (*__pthread_suspend)(pthread_descr);
extern int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *);

/* 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 */