pthread_support.c

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/* 
 * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
 * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
 * Copyright (c) 1998 by Fergus Henderson.  All rights reserved.
 * Copyright (c) 2000-2005 by Hewlett-Packard Company.  All rights reserved.
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
 * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program
 * for any purpose,  provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 */
/*
 * Support code originally for LinuxThreads, the clone()-based kernel
 * thread package for Linux which is included in libc6.
 *
 * This code no doubt makes some assumptions beyond what is
 * guaranteed by the pthread standard, though it now does
 * very little of that.  It now also supports NPTL, and many
 * other Posix thread implementations.  We are trying to merge
 * all flavors of pthread dupport code into this file.
 */
 /* DG/UX ix86 support <[e-mail]> */
/*
 * Linux_threads.c now also includes some code to support HPUX and
 * OSF1 (Compaq Tru64 Unix, really).  The OSF1 support is based on Eric Benson's
 * patch.
 *
 * Eric also suggested an alternate basis for a lock implementation in
 * his code:
 * + #elif defined(OSF1)
 * +    unsigned long GC_allocate_lock = 0;
 * +    msemaphore GC_allocate_semaphore;
 * + #  define GC_TRY_LOCK() \
 * +    ((msem_lock(&GC_allocate_semaphore, MSEM_IF_NOWAIT) == 0) \
 * +     ? (GC_allocate_lock = 1) \
 * +     : 0)
 * + #  define GC_LOCK_TAKEN GC_allocate_lock
 */

/*#define DEBUG_THREADS 1*/

# include "private/pthread_support.h"

# if defined(GC_PTHREADS) && !defined(GC_WIN32_THREADS)

# if defined(GC_DGUX386_THREADS) && !defined(_POSIX4A_DRAFT10_SOURCE)
#   define _POSIX4A_DRAFT10_SOURCE 1
# endif

# if defined(GC_DGUX386_THREADS) && !defined(_USING_POSIX4A_DRAFT10)
#   define _USING_POSIX4A_DRAFT10 1
# endif

# include <stdlib.h>
# include <pthread.h>
# include <sched.h>
# include <time.h>
# include <errno.h>
# include <unistd.h>
# include <sys/mman.h>
# include <sys/time.h>
# include <sys/types.h>
# include <sys/stat.h>
# include <fcntl.h>
# include <signal.h>

# include "gc_inline.h"

#if defined(GC_DARWIN_THREADS)
# include "private/darwin_semaphore.h"
#else
# include <semaphore.h>
#endif /* !GC_DARWIN_THREADS */

#if defined(GC_DARWIN_THREADS) || defined(GC_FREEBSD_THREADS)
# include <sys/sysctl.h>
#endif /* GC_DARWIN_THREADS */

#if defined(GC_NETBSD_THREADS)
# include <sys/param.h>
# include <sys/sysctl.h>
#endif        /* GC_NETBSD_THREADS */

/* Allocator lock definitions.		*/
#if !defined(USE_SPIN_LOCK)
  pthread_mutex_t GC_allocate_ml = PTHREAD_MUTEX_INITIALIZER;
#endif
unsigned long GC_lock_holder = NO_THREAD;
		/* Used only for assertions, and to prevent	 */
		/* recursive reentry in the system call wrapper. */

#if defined(GC_DGUX386_THREADS)
# include <sys/dg_sys_info.h>
# include <sys/_int_psem.h>
  /* sem_t is an uint in DG/UX */
  typedef unsigned int  sem_t;
#endif /* GC_DGUX386_THREADS */

#ifndef __GNUC__
#   define __inline__
#endif

/* Undefine macros used to redirect pthread primitives. */
# undef pthread_create
# if !defined(GC_DARWIN_THREADS)
#   undef pthread_sigmask
# endif
# undef pthread_join
# undef pthread_detach
# if defined(GC_OSF1_THREADS) && defined(_PTHREAD_USE_MANGLED_NAMES_) \
     && !defined(_PTHREAD_USE_PTDNAM_)
  /* Restore the original mangled names on Tru64 UNIX.  */
#   define pthread_create __pthread_create
#   define pthread_join __pthread_join
#   define pthread_detach __pthread_detach
# endif

#ifdef GC_USE_LD_WRAP
#   define WRAP_FUNC(f) __wrap_##f
#   define REAL_FUNC(f) __real_##f
#else
#   ifdef GC_USE_DLOPEN_WRAP
#     include <dlfcn.h>
#     define WRAP_FUNC(f) f
#     define REAL_FUNC(f) GC_real_##f
      /* We define both GC_f and plain f to be the wrapped function.	*/
      /* In that way plain calls work, as do calls from files that	*/
      /* included gc.h, wich redefined f to GC_f.			*/
      /* FIXME: Needs work for DARWIN and True64 (OSF1) */
      typedef int (* GC_pthread_create_t)(pthread_t *, const pthread_attr_t *,
		      		          void * (*)(void *), void *);
      static GC_pthread_create_t GC_real_pthread_create;
      typedef int (* GC_pthread_sigmask_t)(int, const sigset_t *, sigset_t *);
      static GC_pthread_sigmask_t GC_real_pthread_sigmask;
      typedef int (* GC_pthread_join_t)(pthread_t, void **);
      static GC_pthread_join_t GC_real_pthread_join;
      typedef int (* GC_pthread_detach_t)(pthread_t);
      static GC_pthread_detach_t GC_real_pthread_detach;
#   else
#     define WRAP_FUNC(f) GC_##f
#     if !defined(GC_DGUX386_THREADS)
#       define REAL_FUNC(f) f
#     else /* GC_DGUX386_THREADS */
#       define REAL_FUNC(f) __d10_##f
#     endif /* GC_DGUX386_THREADS */
#   endif
#endif

#if defined(GC_USE_DL_WRAP) || defined(GC_USE_DLOPEN_WRAP)
/* Define GC_ functions as aliases for the plain ones, which will	*/
/* be intercepted.  This allows files which include gc.h, and hence	*/
/* generate referemces to the GC_ symbols, to see the right symbols.	*/
      int GC_pthread_create(pthread_t * t, const pthread_attr_t * a,
		         void * (* fn)(void *), void * arg) {
	  return pthread_create(t, a, fn, arg);
      }
      int GC_pthread_sigmask(int how, const sigset_t *mask, sigset_t *old) {
	  return pthread_sigmask(how, mask, old);
      }
      int GC_pthread_join(pthread_t t, void **res) {
	  return pthread_join(t, res);
      }
      int GC_pthread_detach(pthread_t t) {
	  return pthread_detach(t);
      }
#endif /* Linker-based interception. */

#ifdef GC_USE_DLOPEN_WRAP
  static GC_bool GC_syms_initialized = FALSE;

  void GC_init_real_syms(void)
  {
    void *dl_handle;
#   define LIBPTHREAD_NAME "libpthread.so.0"
#   define LIBPTHREAD_NAME_LEN 16 /* incl. trailing 0 */
    size_t len = LIBPTHREAD_NAME_LEN - 1;
    char namebuf[LIBPTHREAD_NAME_LEN];
    static char *libpthread_name = LIBPTHREAD_NAME;

    if (GC_syms_initialized) return;
#   ifdef RTLD_NEXT
      dl_handle = RTLD_NEXT;
#   else
      dl_handle = dlopen(libpthread_name, RTLD_LAZY);
      if (NULL == dl_handle) {
        while (isdigit(libpthread_name[len-1])) --len;
        if (libpthread_name[len-1] == '.') --len;
        memcpy(namebuf, libpthread_name, len);
        namebuf[len] = '\0';
        dl_handle = dlopen(namebuf, RTLD_LAZY);
      }
      if (NULL == dl_handle) ABORT("Couldn't open libpthread\n");
#   endif
    GC_real_pthread_create = (GC_pthread_create_t)
	    			dlsym(dl_handle, "pthread_create");
    GC_real_pthread_sigmask = (GC_pthread_sigmask_t)
	    			dlsym(dl_handle, "pthread_sigmask");
    GC_real_pthread_join = (GC_pthread_join_t)
	    			dlsym(dl_handle, "pthread_join");
    GC_real_pthread_detach = (GC_pthread_detach_t)
	    			dlsym(dl_handle, "pthread_detach");
    GC_syms_initialized = TRUE;
  }

# define INIT_REAL_SYMS() if (!GC_syms_initialized) GC_init_real_syms();
#else
# define INIT_REAL_SYMS()
#endif

void GC_thr_init(void);

static GC_bool parallel_initialized = FALSE;

GC_bool GC_need_to_lock = FALSE;

void GC_init_parallel(void);

long GC_nprocs = 1;	/* Number of processors.  We may not have	*/
			/* access to all of them, but this is as good	*/
			/* a guess as any ...				*/

#ifdef THREAD_LOCAL_ALLOC
/* We must explicitly mark ptrfree and gcj free lists, since the free 	*/
/* list links wouldn't otherwise be found.  We also set them in the 	*/
/* normal free lists, since that involves touching less memory than if	*/
/* we scanned them normally.						*/
void GC_mark_thread_local_free_lists(void)
{
    int i;
    GC_thread p;
    
    for (i = 0; i < THREAD_TABLE_SZ; ++i) {
      for (p = GC_threads[i]; 0 != p; p = p -> next) {
	GC_mark_thread_local_fls_for(&(p->tlfs));
      }
    }
}

#if defined(GC_ASSERTIONS)
    /* Check that all thread-local free-lists are completely marked.	*/
    /* also check that thread-specific-data structures are marked.	*/
    void GC_check_tls(void) {
	int i;
	GC_thread p;
	
	for (i = 0; i < THREAD_TABLE_SZ; ++i) {
	  for (p = GC_threads[i]; 0 != p; p = p -> next) {
	    GC_check_tls_for(&(p->tlfs));
	  }
	}
#       if defined(USE_CUSTOM_SPECIFIC)
	  if (GC_thread_key != 0)
	    GC_check_tsd_marks(GC_thread_key);
#	endif 
    }
#endif /* GC_ASSERTIONS */

#endif /* Thread_local_alloc */

#ifdef PARALLEL_MARK

# ifndef MAX_MARKERS
#   define MAX_MARKERS 16
# endif

static ptr_t marker_sp[MAX_MARKERS] = {0};
#ifdef IA64
  static ptr_t marker_bsp[MAX_MARKERS] = {0};
#endif

void * GC_mark_thread(void * id)
{
  word my_mark_no = 0;

  marker_sp[(word)id] = GC_approx_sp();
# ifdef IA64
    marker_bsp[(word)id] = GC_save_regs_in_stack();
# endif
  for (;; ++my_mark_no) {
    /* GC_mark_no is passed only to allow GC_help_marker to terminate	*/
    /* promptly.  This is important if it were called from the signal	*/
    /* handler or from the GC lock acquisition code.  Under Linux, it's	*/
    /* not safe to call it from a signal handler, since it uses mutexes	*/
    /* and condition variables.  Since it is called only here, the 	*/
    /* argument is unnecessary.						*/
    if (my_mark_no < GC_mark_no || my_mark_no > GC_mark_no + 2) {
	/* resynchronize if we get far off, e.g. because GC_mark_no	*/
	/* wrapped.							*/
	my_mark_no = GC_mark_no;
    }
#   ifdef DEBUG_THREADS
	GC_printf("Starting mark helper for mark number %lu\n", my_mark_no);
#   endif
    GC_help_marker(my_mark_no);
  }
}

extern long GC_markers;		/* Number of mark threads we would	*/
				/* like to have.  Includes the 		*/
				/* initiating thread.			*/

pthread_t GC_mark_threads[MAX_MARKERS];

#define PTHREAD_CREATE REAL_FUNC(pthread_create)

static void start_mark_threads(void)
{
    unsigned i;
    pthread_attr_t attr;

    if (GC_markers > MAX_MARKERS) {
	WARN("Limiting number of mark threads\n", 0);
	GC_markers = MAX_MARKERS;
    }
    if (0 != pthread_attr_init(&attr)) ABORT("pthread_attr_init failed");
	
    if (0 != pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED))
	ABORT("pthread_attr_setdetachstate failed");

#   if defined(HPUX) || defined(GC_DGUX386_THREADS)
      /* Default stack size is usually too small: fix it. */
      /* Otherwise marker threads or GC may run out of	  */
      /* space.						  */
#     define MIN_STACK_SIZE (8*HBLKSIZE*sizeof(word))
      {
	size_t old_size;
	int code;

        if (pthread_attr_getstacksize(&attr, &old_size) != 0)
	  ABORT("pthread_attr_getstacksize failed\n");
	if (old_size < MIN_STACK_SIZE) {
	  if (pthread_attr_setstacksize(&attr, MIN_STACK_SIZE) != 0)
		  ABORT("pthread_attr_setstacksize failed\n");
	}
      }
#   endif /* HPUX || GC_DGUX386_THREADS */
    if (GC_print_stats) {
	GC_log_printf("Starting %ld marker threads\n", GC_markers - 1);
    }
    for (i = 0; i < GC_markers - 1; ++i) {
      if (0 != PTHREAD_CREATE(GC_mark_threads + i, &attr,
			      GC_mark_thread, (void *)(word)i)) {
	WARN("Marker thread creation failed, errno = %ld.\n", errno);
      }
    }
}

#endif /* PARALLEL_MARK */

GC_bool GC_thr_initialized = FALSE;

volatile GC_thread GC_threads[THREAD_TABLE_SZ];

void GC_push_thread_structures(void)
{
    GC_ASSERT(I_HOLD_LOCK());
    GC_push_all((ptr_t)(GC_threads), (ptr_t)(GC_threads)+sizeof(GC_threads));
#   if defined(THREAD_LOCAL_ALLOC)
      GC_push_all((ptr_t)(&GC_thread_key),
	  (ptr_t)(&GC_thread_key)+sizeof(&GC_thread_key));
#   endif
}

/* It may not be safe to allocate when we register the first thread.	*/
static struct GC_Thread_Rep first_thread;

/* Add a thread to GC_threads.  We assume it wasn't already there.	*/
/* Caller holds allocation lock.					*/
GC_thread GC_new_thread(pthread_t id)
{
    int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
    GC_thread result;
    static GC_bool first_thread_used = FALSE;
    
    GC_ASSERT(I_HOLD_LOCK());
    if (!first_thread_used) {
    	result = &first_thread;
    	first_thread_used = TRUE;
    } else {
        result = (struct GC_Thread_Rep *)
        	 GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL);
	GC_ASSERT(result -> flags == 0);
    }
    if (result == 0) return(0);
    result -> id = id;
    result -> next = GC_threads[hv];
    GC_threads[hv] = result;
    GC_ASSERT(result -> flags == 0 && result -> thread_blocked == 0);
    return(result);
}

/* Delete a thread from GC_threads.  We assume it is there.	*/
/* (The code intentionally traps if it wasn't.)			*/
void GC_delete_thread(pthread_t id)
{
    int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
    register GC_thread p = GC_threads[hv];
    register GC_thread prev = 0;
    
    GC_ASSERT(I_HOLD_LOCK());
    while (!THREAD_EQUAL(p -> id, id)) {
        prev = p;
        p = p -> next;
    }
    if (prev == 0) {
        GC_threads[hv] = p -> next;
    } else {
        prev -> next = p -> next;
    }
#   ifdef GC_DARWIN_THREADS
	mach_port_deallocate(mach_task_self(), p->stop_info.mach_thread);
#   endif
    GC_INTERNAL_FREE(p);
}

/* If a thread has been joined, but we have not yet		*/
/* been notified, then there may be more than one thread 	*/
/* in the table with the same pthread id.			*/
/* This is OK, but we need a way to delete a specific one.	*/
void GC_delete_gc_thread(GC_thread gc_id)
{
    pthread_t id = gc_id -> id;
    int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
    register GC_thread p = GC_threads[hv];
    register GC_thread prev = 0;

    GC_ASSERT(I_HOLD_LOCK());
    while (p != gc_id) {
        prev = p;
        p = p -> next;
    }
    if (prev == 0) {
        GC_threads[hv] = p -> next;
    } else {
        prev -> next = p -> next;
    }
#   ifdef GC_DARWIN_THREADS
	mach_port_deallocate(mach_task_self(), p->stop_info.mach_thread);
#   endif
    GC_INTERNAL_FREE(p);
}

/* Return a GC_thread corresponding to a given pthread_t.	*/
/* Returns 0 if it's not there.					*/
/* Caller holds  allocation lock or otherwise inhibits 		*/
/* updates.							*/
/* If there is more than one thread with the given id we 	*/
/* return the most recent one.					*/
GC_thread GC_lookup_thread(pthread_t id)
{
    int hv = NUMERIC_THREAD_ID(id) % THREAD_TABLE_SZ;
    register GC_thread p = GC_threads[hv];
    
    while (p != 0 && !THREAD_EQUAL(p -> id, id)) p = p -> next;
    return(p);
}

#ifdef HANDLE_FORK
/* Remove all entries from the GC_threads table, except the	*/
/* one for the current thread.  We need to do this in the child	*/
/* process after a fork(), since only the current thread 	*/
/* survives in the child.					*/
void GC_remove_all_threads_but_me(void)
{
    pthread_t self = pthread_self();
    int hv;
    GC_thread p, next, me;

    for (hv = 0; hv < THREAD_TABLE_SZ; ++hv) {
      me = 0;
      for (p = GC_threads[hv]; 0 != p; p = next) {
	next = p -> next;
	if (THREAD_EQUAL(p -> id, self)) {
	  me = p;
	  p -> next = 0;
	} else {
#	  ifdef THREAD_LOCAL_ALLOC
	    if (!(p -> flags & FINISHED)) {
	      GC_destroy_thread_local(&(p->tlfs));
	    }
#	  endif /* THREAD_LOCAL_ALLOC */
	  if (p != &first_thread) GC_INTERNAL_FREE(p);
	}
      }
      GC_threads[hv] = me;
    }
}
#endif /* HANDLE_FORK */

#ifdef USE_PROC_FOR_LIBRARIES
GC_bool GC_segment_is_thread_stack(ptr_t lo, ptr_t hi)
{
    int i;
    GC_thread p;