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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) 2000-2008 by Hewlett-Packard Company. All rights reserved.
* Copyright (c) 2008-2022 Ivan Maidanski
*
* 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.
*/
#include "private/pthread_support.h"
/*
* 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 support code into this file.
*/
#ifdef THREADS
# ifdef GC_PTHREADS
# if defined(DARWIN) \
|| (defined(GC_WIN32_THREADS) && defined(EMULATE_PTHREAD_SEMAPHORE))
# include "private/darwin_semaphore.h"
# elif !defined(PLATFORM_THREADS) && !defined(SN_TARGET_PSP2)
# include <semaphore.h>
# endif
# include <errno.h>
# endif /* GC_PTHREADS */
# if !defined(GC_WIN32_THREADS)
# include <sched.h>
# include <time.h>
# if !defined(PLATFORM_THREADS) && !defined(SN_TARGET_PSP2)
# ifndef RTEMS
# include <sys/mman.h>
# endif
# include <fcntl.h>
# include <sys/stat.h>
# include <sys/time.h>
# endif
# if defined(GC_EXPLICIT_SIGNALS_UNBLOCK) \
|| !defined(GC_NO_PTHREAD_SIGMASK) \
|| (defined(GC_PTHREADS_PARAMARK) \
&& !defined(NO_MARKER_SPECIAL_SIGMASK))
# include <signal.h>
# endif
# endif /* !GC_WIN32_THREADS */
# ifdef E2K
# include <alloca.h>
# endif
# if defined(DARWIN) || defined(ANY_BSD)
# if defined(NETBSD) || defined(OPENBSD)
# include <sys/param.h>
# endif
# include <sys/sysctl.h>
# elif defined(DGUX)
# include <sys/_int_psem.h>
# include <sys/dg_sys_info.h>
/* sem_t is an uint in DG/UX */
typedef unsigned int sem_t;
# endif
# if defined(GC_PTHREADS) && !defined(PLATFORM_THREADS) \
&& !defined(SN_TARGET_PSP2)
/* Undefine macros used to redirect pthread primitives. */
# undef pthread_create
# ifndef GC_NO_PTHREAD_SIGMASK
# undef pthread_sigmask
# endif
# ifndef GC_NO_PTHREAD_CANCEL
# undef pthread_cancel
# endif
# ifdef GC_HAVE_PTHREAD_EXIT
# undef pthread_exit
# endif
# undef pthread_join
# undef pthread_detach
# if defined(OSF1) && 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
# ifndef GC_NO_PTHREAD_CANCEL
# define pthread_cancel __pthread_cancel
# endif
# ifdef GC_HAVE_PTHREAD_EXIT
# define pthread_exit __pthread_exit
# endif
# endif
# endif /* GC_PTHREADS */
# if !defined(GC_WIN32_THREADS) && !defined(PLATFORM_THREADS) \
&& !defined(SN_TARGET_PSP2)
/* TODO: Enable GC_USE_DLOPEN_WRAP for Cygwin? */
# ifdef GC_USE_LD_WRAP
# define WRAP_FUNC(f) __wrap_##f
# define REAL_FUNC(f) __real_##f
int REAL_FUNC(pthread_create)(pthread_t *,
GC_PTHREAD_CREATE_CONST pthread_attr_t *,
void *(*start_routine)(void *), void *);
int REAL_FUNC(pthread_join)(pthread_t, void **);
int REAL_FUNC(pthread_detach)(pthread_t);
# ifndef GC_NO_PTHREAD_SIGMASK
int REAL_FUNC(pthread_sigmask)(int, const sigset_t *, sigset_t *);
# endif
# ifndef GC_NO_PTHREAD_CANCEL
int REAL_FUNC(pthread_cancel)(pthread_t);
# endif
# ifdef GC_HAVE_PTHREAD_EXIT
void REAL_FUNC(pthread_exit)(void *) GC_PTHREAD_EXIT_ATTRIBUTE;
# endif
# elif defined(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, which redefined f to GC_f. */
/* FIXME: Needs work for DARWIN and True64 (OSF1) */
typedef int (*GC_pthread_create_t)(pthread_t *,
GC_PTHREAD_CREATE_CONST pthread_attr_t *,
void *(*)(void *), void *);
static GC_pthread_create_t REAL_FUNC(pthread_create);
# ifndef GC_NO_PTHREAD_SIGMASK
typedef int (*GC_pthread_sigmask_t)(int, const sigset_t *, sigset_t *);
static GC_pthread_sigmask_t REAL_FUNC(pthread_sigmask);
# endif
typedef int (*GC_pthread_join_t)(pthread_t, void **);
static GC_pthread_join_t REAL_FUNC(pthread_join);
typedef int (*GC_pthread_detach_t)(pthread_t);
static GC_pthread_detach_t REAL_FUNC(pthread_detach);
# ifndef GC_NO_PTHREAD_CANCEL
typedef int (*GC_pthread_cancel_t)(pthread_t);
static GC_pthread_cancel_t REAL_FUNC(pthread_cancel);
# endif
# ifdef GC_HAVE_PTHREAD_EXIT
typedef void (*GC_pthread_exit_t)(void *) GC_PTHREAD_EXIT_ATTRIBUTE;
static GC_pthread_exit_t REAL_FUNC(pthread_exit);
# endif
# else
# define WRAP_FUNC(f) GC_##f
# ifdef DGUX
# define REAL_FUNC(f) __d10_##f
# else
# define REAL_FUNC(f) f
# endif
# endif /* !GC_USE_LD_WRAP && !GC_USE_DLOPEN_WRAP */
# if defined(GC_USE_LD_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 references to the GC_ symbols, to see the right ones. */
GC_API int
GC_pthread_create(pthread_t *t, GC_PTHREAD_CREATE_CONST pthread_attr_t *a,
void *(*fn)(void *), void *arg)
{
return pthread_create(t, a, fn, arg);
}
# ifndef GC_NO_PTHREAD_SIGMASK
GC_API int
GC_pthread_sigmask(int how, const sigset_t *mask, sigset_t *old)
{
return pthread_sigmask(how, mask, old);
}
# endif /* !GC_NO_PTHREAD_SIGMASK */
GC_API int
GC_pthread_join(pthread_t t, void **res)
{
return pthread_join(t, res);
}
GC_API int
GC_pthread_detach(pthread_t t)
{
return pthread_detach(t);
}
# ifndef GC_NO_PTHREAD_CANCEL
GC_API int
GC_pthread_cancel(pthread_t t)
{
return pthread_cancel(t);
}
# endif /* !GC_NO_PTHREAD_CANCEL */
# ifdef GC_HAVE_PTHREAD_EXIT
GC_API GC_PTHREAD_EXIT_ATTRIBUTE void
GC_pthread_exit(void *retval)
{
pthread_exit(retval);
}
# endif
# endif /* GC_USE_LD_WRAP || GC_USE_DLOPEN_WRAP */
# ifdef GC_USE_DLOPEN_WRAP
STATIC GC_bool GC_syms_initialized = FALSE;
/* Resolve a symbol from the dynamic library (given by a handle) */
/* and cast it to the given functional type. */
# define TYPED_DLSYM(fn, h, name) CAST_THRU_UINTPTR(fn, dlsym(h, name))
STATIC void
GC_init_real_syms(void)
{
void *dl_handle;
GC_ASSERT(!GC_syms_initialized);
# ifdef RTLD_NEXT
dl_handle = RTLD_NEXT;
# else
dl_handle = dlopen("libpthread.so.0", RTLD_LAZY);
if (NULL == dl_handle) {
/* Retry without ".0" suffix. */
dl_handle = dlopen("libpthread.so", RTLD_LAZY);
if (NULL == dl_handle)
ABORT("Couldn't open libpthread");
}
# endif
REAL_FUNC(pthread_create)
= TYPED_DLSYM(GC_pthread_create_t, dl_handle, "pthread_create");
# ifdef RTLD_NEXT
if (REAL_FUNC(pthread_create) == 0)
ABORT("pthread_create not found"
" (probably -lgc is specified after -lpthread)");
# endif
# ifndef GC_NO_PTHREAD_SIGMASK
REAL_FUNC(pthread_sigmask)
= TYPED_DLSYM(GC_pthread_sigmask_t, dl_handle, "pthread_sigmask");
# endif
REAL_FUNC(pthread_join)
= TYPED_DLSYM(GC_pthread_join_t, dl_handle, "pthread_join");
REAL_FUNC(pthread_detach)
= TYPED_DLSYM(GC_pthread_detach_t, dl_handle, "pthread_detach");
# ifndef GC_NO_PTHREAD_CANCEL
REAL_FUNC(pthread_cancel)
= TYPED_DLSYM(GC_pthread_cancel_t, dl_handle, "pthread_cancel");
# endif
# ifdef GC_HAVE_PTHREAD_EXIT
REAL_FUNC(pthread_exit)
= TYPED_DLSYM(GC_pthread_exit_t, dl_handle, "pthread_exit");
# endif
GC_syms_initialized = TRUE;
}
# define INIT_REAL_SYMS() \
if (EXPECT(GC_syms_initialized, TRUE)) { \
} else \
GC_init_real_syms()
# else
# define INIT_REAL_SYMS() (void)0
# endif /* !GC_USE_DLOPEN_WRAP */
# else
# define WRAP_FUNC(f) GC_##f
# define REAL_FUNC(f) f
# define INIT_REAL_SYMS() (void)0
# endif /* GC_WIN32_THREADS */
# if defined(MPROTECT_VDB) && defined(DARWIN)
GC_INNER int
GC_inner_pthread_create(pthread_t *t,
GC_PTHREAD_CREATE_CONST pthread_attr_t *a,
void *(*fn)(void *), void *arg)
{
INIT_REAL_SYMS();
return REAL_FUNC(pthread_create)(t, a, fn, arg);
}
# endif
# ifndef GC_ALWAYS_MULTITHREADED
GC_INNER GC_bool GC_need_to_lock = FALSE;
# endif
# 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. */
GC_INNER 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]; p != NULL; p = p->tm.next) {
if (!KNOWN_FINISHED(p))
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]; p != NULL; p = p->tm.next) {
if (!KNOWN_FINISHED(p))
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
# endif /* THREAD_LOCAL_ALLOC */
# ifdef GC_WIN32_THREADS
/* A macro for functions and variables which should be accessible */
/* from win32_threads.c but otherwise could be static. */
# define GC_INNER_WIN32THREAD GC_INNER
# else
# define GC_INNER_WIN32THREAD STATIC
# endif
# ifdef PARALLEL_MARK
# if defined(GC_WIN32_THREADS) || defined(USE_PROC_FOR_LIBRARIES) \
|| (defined(IA64) \
&& (defined(HAVE_PTHREAD_ATTR_GET_NP) \
|| defined(HAVE_PTHREAD_GETATTR_NP)))
/* The cold end of the stack for markers. */
GC_INNER_WIN32THREAD ptr_t GC_marker_sp[MAX_MARKERS - 1] = { 0 };
# endif /* GC_WIN32_THREADS || USE_PROC_FOR_LIBRARIES */
# if defined(IA64) && defined(USE_PROC_FOR_LIBRARIES)
static ptr_t marker_bsp[MAX_MARKERS - 1] = { 0 };
# endif
# if defined(DARWIN) && !defined(GC_NO_THREADS_DISCOVERY)
static mach_port_t marker_mach_threads[MAX_MARKERS - 1] = { 0 };
/* Used only by GC_suspend_thread_list(). */
GC_INNER GC_bool
GC_is_mach_marker(thread_act_t thread)
{
int i;
for (i = 0; i < GC_markers_m1; i++) {
if (marker_mach_threads[i] == thread)
return TRUE;
}
return FALSE;
}
# endif /* DARWIN && !GC_NO_THREADS_DISCOVERY */
# ifdef HAVE_PTHREAD_SETNAME_NP_WITH_TID_AND_ARG
/* For NetBSD. */
static void
set_marker_thread_name(unsigned id)
{
int err = pthread_setname_np(pthread_self(), "GC-marker-%zu",
NUMERIC_TO_VPTR(id));
if (EXPECT(err != 0, FALSE))
WARN("pthread_setname_np failed, errno= %" WARN_PRIdPTR "\n",
(GC_signed_word)err);
}
# elif defined(HAVE_PTHREAD_SETNAME_NP_WITH_TID) \
|| defined(HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID) \
|| defined(HAVE_PTHREAD_SET_NAME_NP)
# ifdef HAVE_PTHREAD_SET_NAME_NP
# include <pthread_np.h>
# endif
static void
set_marker_thread_name(unsigned id)
{
char name_buf[16]; /* pthread_setname_np may fail for longer names */
int len = sizeof("GC-marker-") - 1;
/* Compose the name manually as snprintf may be unavailable or */
/* "%u directive output may be truncated" warning may occur. */
BCOPY("GC-marker-", name_buf, len);
if (id >= 10)
name_buf[len++] = (char)('0' + (id / 10) % 10);
name_buf[len] = (char)('0' + id % 10);
name_buf[len + 1] = '\0';
# ifdef HAVE_PTHREAD_SETNAME_NP_WITHOUT_TID
/* The iOS or OS X case. */
(void)pthread_setname_np(name_buf);
# elif defined(HAVE_PTHREAD_SET_NAME_NP)
/* The OpenBSD case. */
pthread_set_name_np(pthread_self(), name_buf);
# else
/* The case of Linux, Solaris, etc. */
if (EXPECT(pthread_setname_np(pthread_self(), name_buf) != 0, FALSE))
WARN("pthread_setname_np failed\n", 0);
# endif
}
# elif defined(GC_WIN32_THREADS) && !defined(MSWINCE)
/* A pointer to SetThreadDescription() which is available since */
/* Windows 10. The function prototype is in processthreadsapi.h. */
static FARPROC setThreadDescription_fn;
GC_INNER void
GC_init_win32_thread_naming(HMODULE hK32)
{
if (hK32)
setThreadDescription_fn = GetProcAddress(hK32, "SetThreadDescription");
}
static void
set_marker_thread_name(unsigned id)
{
WCHAR name_buf[16];
int len = sizeof(L"GC-marker-") / sizeof(WCHAR) - 1;
HRESULT hr;
if (!setThreadDescription_fn) {
/* SetThreadDescription() is missing. */
return;
}
/* Compose the name manually as swprintf may be unavailable. */
BCOPY(L"GC-marker-", name_buf, len * sizeof(WCHAR));
if (id >= 10)
name_buf[len++] = (WCHAR)('0' + (id / 10) % 10);
name_buf[len] = (WCHAR)('0' + id % 10);
name_buf[len + 1] = 0;
/* Invoke SetThreadDescription(). Cast the function pointer to word */
/* first to avoid "incompatible function types" compiler warning. */
hr = (*(HRESULT(WINAPI *)(HANDLE, const WCHAR *))(
GC_funcptr_uint)setThreadDescription_fn)(GetCurrentThread(), name_buf);
if (hr < 0)
WARN("SetThreadDescription failed\n", 0);
}
# else
# define set_marker_thread_name(id) (void)(id)
# endif
GC_INNER_WIN32THREAD
# ifdef GC_PTHREADS_PARAMARK
void *
GC_mark_thread(void *id)
# elif defined(MSWINCE)
DWORD WINAPI
GC_mark_thread(LPVOID id)
# else
unsigned __stdcall GC_mark_thread(void *id)
# endif
{
word my_mark_no = 0;
word id_n = (word)(GC_uintptr_t)id;
IF_CANCEL(int cancel_state;)
if (id_n == GC_WORD_MAX)
return 0; /* to prevent a compiler warning */
/* Mark threads are not cancellable; they should be invisible to */
/* client. */
DISABLE_CANCEL(cancel_state);
set_marker_thread_name((unsigned)id_n);
# if defined(GC_WIN32_THREADS) || defined(USE_PROC_FOR_LIBRARIES) \
|| (defined(IA64) \
&& (defined(HAVE_PTHREAD_ATTR_GET_NP) \
|| defined(HAVE_PTHREAD_GETATTR_NP)))
GC_marker_sp[id_n] = GC_approx_sp();
# endif
# if defined(IA64) && defined(USE_PROC_FOR_LIBRARIES)
marker_bsp[id_n] = GC_save_regs_in_stack();
# endif
# if defined(DARWIN) && !defined(GC_NO_THREADS_DISCOVERY)
marker_mach_threads[id_n] = mach_thread_self();
# endif
# if !defined(GC_PTHREADS_PARAMARK)
GC_marker_Id[id_n] = thread_id_self();
# endif
/* Inform GC_start_mark_threads about completion of marker data init. */
GC_acquire_mark_lock();
/* Note: the count variable may have a negative value. */
if (0 == --GC_fl_builder_count)
GC_notify_all_builder();
/* 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 allocator lock acquisition code. Under */
/* Linux, it is 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. */
for (;; ++my_mark_no) {
if (my_mark_no - GC_mark_no > (word)2) {
/* Resynchronize if we get far off, e.g. because GC_mark_no */
/* wrapped. */
my_mark_no = GC_mark_no;
}
# ifdef DEBUG_THREADS
GC_log_printf("Starting helper for mark number %lu (thread %u)\n",
(unsigned long)my_mark_no, (unsigned)id_n);
# endif
GC_help_marker(my_mark_no);
}
}
GC_INNER_WIN32THREAD int GC_available_markers_m1 = 0;
# endif /* PARALLEL_MARK */
# ifdef GC_PTHREADS_PARAMARK
# ifdef GLIBC_2_1_MUTEX_HACK
/* Ugly workaround for a linux threads bug in the final versions */
/* of glibc 2.1. Pthread_mutex_trylock sets the mutex owner */
/* field even when it fails to acquire the mutex. This causes */
/* pthread_cond_wait to die. Should not be needed for glibc 2.2. */
/* According to the man page, we should use */
/* PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP, but that isn't actually */
/* defined. */
static pthread_mutex_t mark_mutex
= { 0, 0, 0, PTHREAD_MUTEX_ERRORCHECK_NP, { 0, 0 } };
# else
static pthread_mutex_t mark_mutex = PTHREAD_MUTEX_INITIALIZER;
# endif
# ifdef CAN_HANDLE_FORK
/* Note: this is initialized by GC_start_mark_threads_inner(). */
static pthread_cond_t mark_cv;
# else
static pthread_cond_t mark_cv = PTHREAD_COND_INITIALIZER;
# endif
GC_INNER void
GC_start_mark_threads_inner(void)
{
int i;
pthread_attr_t attr;
# ifndef NO_MARKER_SPECIAL_SIGMASK
sigset_t set, oldset;
# endif
GC_ASSERT(I_HOLD_LOCK());
ASSERT_CANCEL_DISABLED();
if (GC_available_markers_m1 <= 0 || GC_parallel) {
/* Skip if parallel markers disabled or already started. */
return;
}
GC_wait_for_gc_completion(TRUE);
# ifdef CAN_HANDLE_FORK
/* Initialize mark_cv (for the first time), or cleanup its value */
/* after forking in the child process. All the marker threads in */
/* the parent process were blocked on this variable at fork, so */
/* pthread_cond_wait() malfunction (hang) is possible in the */
/* child process without such a cleanup. */
/* TODO: This is not portable, it is better to shortly unblock */
/* all marker threads in the parent process at fork. */
{
pthread_cond_t mark_cv_local = PTHREAD_COND_INITIALIZER;
BCOPY(&mark_cv_local, &mark_cv, sizeof(mark_cv));
}
# endif
GC_ASSERT(0 == GC_fl_builder_count);
INIT_REAL_SYMS(); /* for pthread_create */
if (pthread_attr_init(&attr) != 0)
ABORT("pthread_attr_init failed");
if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) != 0)
ABORT("pthread_attr_setdetachstate failed");
# ifdef DEFAULT_STACK_MAYBE_SMALL
/* Default stack size is usually too small: increase it. */
/* Otherwise marker threads or GC may run out of space. */
{
size_t old_size;
if (pthread_attr_getstacksize(&attr, &old_size) != 0)
ABORT("pthread_attr_getstacksize failed");
if (old_size < MIN_STACK_SIZE && old_size != 0 /* stack size is known */) {
if (pthread_attr_setstacksize(&attr, MIN_STACK_SIZE) != 0)
ABORT("pthread_attr_setstacksize failed");
}
}
# endif /* DEFAULT_STACK_MAYBE_SMALL */
# ifndef NO_MARKER_SPECIAL_SIGMASK
/* Apply special signal mask to GC marker threads, and don't drop */
/* user defined signals by GC marker threads. */
if (sigfillset(&set) != 0)
ABORT("sigfillset failed");
# ifdef SIGNAL_BASED_STOP_WORLD
/* These are used by GC to stop and restart the world. */
if (sigdelset(&set, GC_get_suspend_signal()) != 0
|| sigdelset(&set, GC_get_thr_restart_signal()) != 0)
ABORT("sigdelset failed");
# endif
if (EXPECT(REAL_FUNC(pthread_sigmask)(SIG_BLOCK, &set, &oldset) != 0,
FALSE)) {
WARN("pthread_sigmask set failed, no markers started\n", 0);
GC_markers_m1 = 0;
(void)pthread_attr_destroy(&attr);
return;
}
# endif /* !NO_MARKER_SPECIAL_SIGMASK */
/* To have proper GC_parallel value in GC_help_marker. */
GC_markers_m1 = GC_available_markers_m1;
for (i = 0; i < GC_available_markers_m1; ++i) {
pthread_t new_thread;
# ifdef GC_WIN32_THREADS
GC_marker_last_stack_min[i] = ADDR_LIMIT;
# endif
if (EXPECT(REAL_FUNC(pthread_create)(&new_thread, &attr, GC_mark_thread,
NUMERIC_TO_VPTR(i))
!= 0,
FALSE)) {
WARN("Marker thread %" WARN_PRIdPTR " creation failed\n",
(GC_signed_word)i);
/* Don't try to create other marker threads. */
GC_markers_m1 = i;
break;
}
}
# ifndef NO_MARKER_SPECIAL_SIGMASK
/* Restore previous signal mask. */
if (EXPECT(REAL_FUNC(pthread_sigmask)(SIG_SETMASK, &oldset, NULL) != 0,
FALSE)) {
WARN("pthread_sigmask restore failed\n", 0);
}
# endif
(void)pthread_attr_destroy(&attr);
GC_wait_for_markers_init();
GC_COND_LOG_PRINTF("Started %d mark helper threads\n", GC_markers_m1);
}
# endif /* GC_PTHREADS_PARAMARK */
/* A hash table to keep information about the registered threads. */
/* Not used if GC_win32_dll_threads is set. */
GC_INNER GC_thread GC_threads[THREAD_TABLE_SZ] = { 0 };
/* It may not be safe to allocate when we register the first thread. */
/* Note that next and status fields are unused, but there might be some */
/* other fields (crtn) to be pushed. */
static struct GC_StackContext_Rep first_crtn;
static struct GC_Thread_Rep first_thread;
/* A place to retain a pointer to an allocated object while a thread */
/* registration is ongoing. Protected by the allocator lock. */
static GC_stack_context_t saved_crtn = NULL;
# ifdef GC_ASSERTIONS
GC_INNER GC_bool GC_thr_initialized = FALSE;
# endif
GC_INNER void
GC_push_thread_structures(void)
{
GC_ASSERT(I_HOLD_LOCK());
# if !defined(GC_NO_THREADS_DISCOVERY) && defined(GC_WIN32_THREADS)
if (GC_win32_dll_threads) {
/* Unlike the other threads implementations, the thread table */
/* here contains no pointers to the collectible heap (note also */
/* that GC_PTHREADS is incompatible with DllMain-based thread */
/* registration). Thus we have no private structures we need */
/* to preserve. */
} else
# endif
/* else */ {
GC_push_all(&GC_threads, (ptr_t)(&GC_threads) + sizeof(GC_threads));
GC_ASSERT(NULL == first_thread.tm.next);
# ifdef GC_PTHREADS
GC_ASSERT(NULL == first_thread.status);
# endif
GC_PUSH_ALL_SYM(first_thread.crtn);
GC_PUSH_ALL_SYM(saved_crtn);
}
# if defined(THREAD_LOCAL_ALLOC) && defined(USE_CUSTOM_SPECIFIC)
GC_PUSH_ALL_SYM(GC_thread_key);
# endif
}
# if defined(MPROTECT_VDB) && defined(GC_WIN32_THREADS)
GC_INNER void
GC_win32_unprotect_thread(GC_thread t)
{
GC_ASSERT(I_HOLD_LOCK());
if (!GC_win32_dll_threads && GC_auto_incremental) {
GC_stack_context_t crtn = t->crtn;
if (crtn != &first_crtn) {
GC_ASSERT(SMALL_OBJ(GC_size(crtn)));
GC_remove_protection(HBLKPTR(crtn), 1, FALSE);
}
if (t != &first_thread) {
GC_ASSERT(SMALL_OBJ(GC_size(t)));
GC_remove_protection(HBLKPTR(t), 1, FALSE);
}
}
}
# endif /* MPROTECT_VDB && GC_WIN32_THREADS */
# ifdef DEBUG_THREADS
STATIC int
GC_count_threads(void)
{
int i;
int count = 0;
# if !defined(GC_NO_THREADS_DISCOVERY) && defined(GC_WIN32_THREADS)
if (GC_win32_dll_threads)
return -1; /* not implemented */
# endif
GC_ASSERT(I_HOLD_READER_LOCK());
for (i = 0; i < THREAD_TABLE_SZ; ++i) {
GC_thread p;
for (p = GC_threads[i]; p != NULL; p = p->tm.next) {
if (!KNOWN_FINISHED(p))
++count;
}
}
return count;
}
# endif /* DEBUG_THREADS */
/* Add a thread to GC_threads. We assume it wasn't already there. */
/* The id field is set by the caller. */
GC_INNER_WIN32THREAD GC_thread
GC_new_thread(thread_id_t self_id)
{
int hv = THREAD_TABLE_INDEX(self_id);
GC_thread result;
GC_ASSERT(I_HOLD_LOCK());
# ifdef DEBUG_THREADS
GC_log_printf("Creating thread %p\n", THREAD_ID_TO_VPTR(self_id));
for (result = GC_threads[hv]; result != NULL; result = result->tm.next)
if (!THREAD_ID_EQUAL(result->id, self_id)) {
GC_log_printf("Hash collision at GC_threads[%d]\n", hv);
break;
}
# endif
if (EXPECT(NULL == first_thread.crtn, FALSE)) {
result = &first_thread;
first_thread.crtn = &first_crtn;
GC_ASSERT(NULL == GC_threads[hv]);
# if defined(CPPCHECK) && defined(THREAD_SANITIZER) \
&& defined(SIGNAL_BASED_STOP_WORLD)
GC_noop1((unsigned char)first_crtn.dummy[0]);
# endif
} else {
GC_stack_context_t crtn;
GC_ASSERT(!GC_win32_dll_threads);
GC_ASSERT(!GC_in_thread_creation);
GC_in_thread_creation = TRUE; /* OK to collect from unknown thread */
crtn = (GC_stack_context_t)GC_INTERNAL_MALLOC(
sizeof(struct GC_StackContext_Rep), NORMAL);
/* The current stack is not scanned until the thread is */
/* registered, thus crtn pointer is to be retained in the */
/* global data roots for a while (and pushed explicitly if */
/* a collection occurs here). */
GC_ASSERT(NULL == saved_crtn);
saved_crtn = crtn;
result
= (GC_thread)GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL);
/* No more collections till thread is registered. */
saved_crtn = NULL;
GC_in_thread_creation = FALSE;
if (NULL == crtn || NULL == result)
ABORT("Failed to allocate memory for thread registering");
result->crtn = crtn;
}
/* The id field is not set here. */
# ifdef USE_TKILL_ON_ANDROID
result->kernel_id = gettid();
# endif
result->tm.next = GC_threads[hv];
GC_threads[hv] = result;
# ifdef NACL
GC_nacl_initialize_gc_thread(result);
# endif
GC_ASSERT(0 == result->flags);
if (EXPECT(result != &first_thread, TRUE))
GC_dirty(result);
return result;
}
/* Delete a thread from GC_threads. We assume it is there. (The code */
/* intentionally traps if it was not.) It is also safe to delete the */
/* main thread. If GC_win32_dll_threads is set, it should be called */
/* only from the thread being deleted. 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 thread id - this is OK because we */
/* delete a specific one. */
GC_INNER_WIN32THREAD void
GC_delete_thread(GC_thread t)
{
# if defined(GC_WIN32_THREADS) && !defined(MSWINCE)
CloseHandle(t->handle);
# endif
# if !defined(GC_NO_THREADS_DISCOVERY) && defined(GC_WIN32_THREADS)
if (GC_win32_dll_threads) {
/* This is intended to be lock-free. It is either called */
/* synchronously from the thread being deleted, or by the joining */
/* thread. In this branch asynchronous changes to (*t) are */
/* possible. Note that it is not allowed to call GC_printf (and */
/* the friends) here, see GC_stop_world() in win32_threads.c for */
/* the information. */
t->crtn->stack_end = NULL;
t->id = 0;
/* The thread is not suspended. */
t->flags = 0;
# ifdef RETRY_GET_THREAD_CONTEXT
t->context_sp = NULL;
# endif
AO_store_release(&t->tm.in_use, FALSE);
} else
# endif
/* else */ {
thread_id_t id = t->id;
int hv = THREAD_TABLE_INDEX(id);
GC_thread p;
GC_thread prev = NULL;
GC_ASSERT(I_HOLD_LOCK());
# if defined(DEBUG_THREADS) && !defined(MSWINCE) \
&& (!defined(MSWIN32) || defined(CONSOLE_LOG))
GC_log_printf("Deleting thread %p, n_threads= %d\n", THREAD_ID_TO_VPTR(id),
GC_count_threads());
# endif
for (p = GC_threads[hv]; p != t; p = p->tm.next) {
prev = p;
}
if (NULL == prev) {
GC_threads[hv] = p->tm.next;
} else {
GC_ASSERT(prev != &first_thread);
prev->tm.next = p->tm.next;
GC_dirty(prev);
}
if (EXPECT(p != &first_thread, TRUE)) {
# ifdef DARWIN
mach_port_deallocate(mach_task_self(), p->mach_thread);
# endif
GC_ASSERT(p->crtn != &first_crtn);
GC_INTERNAL_FREE(p->crtn);
GC_INTERNAL_FREE(p);
}
}
}
/* Return a GC_thread corresponding to a given thread id, or */
/* NULL if it is not there. Caller holds the allocator lock */
/* at least in the reader mode or otherwise inhibits updates. */
/* If there is more than one thread with the given id, we */
/* return the most recent one. */
GC_INNER GC_thread
GC_lookup_thread(thread_id_t id)
{
GC_thread p;
# if !defined(GC_NO_THREADS_DISCOVERY) && defined(GC_WIN32_THREADS)
if (GC_win32_dll_threads)
return GC_win32_dll_lookup_thread(id);
# endif
for (p = GC_threads[THREAD_TABLE_INDEX(id)]; p != NULL; p = p->tm.next) {
if (EXPECT(THREAD_ID_EQUAL(p->id, id), TRUE))
break;
}
return p;
}
/* Same as GC_self_thread_inner() but acquires the allocator lock (in */
/* the reader mode). */
STATIC GC_thread
GC_self_thread(void)
{
GC_thread p;
READER_LOCK();
p = GC_self_thread_inner();
READER_UNLOCK();
return p;
}
# ifndef GC_NO_FINALIZATION
/* Called by GC_finalize() (in case of an allocation failure observed). */
GC_INNER void
GC_reset_finalizer_nested(void)
{
GC_ASSERT(I_HOLD_LOCK());
GC_self_thread_inner()->crtn->finalizer_nested = 0;
}
/* Checks and updates the thread-local level of finalizers recursion. */
/* Returns NULL if GC_invoke_finalizers() should not be called by the */
/* collector (to minimize the risk of a deep finalizers recursion), */
/* otherwise returns a pointer to the thread-local finalizer_nested. */
/* Called by GC_notify_or_invoke_finalizers() only. */
GC_INNER unsigned char *
GC_check_finalizer_nested(void)
{
GC_thread me;
GC_stack_context_t crtn;
unsigned nesting_level;
GC_ASSERT(I_HOLD_LOCK());
me = GC_self_thread_inner();
# if defined(INCLUDE_LINUX_THREAD_DESCR) && defined(REDIRECT_MALLOC)
/* As noted in GC_pthread_start, an allocation may happen in */
/* GC_get_stack_base, causing GC_notify_or_invoke_finalizers */
/* to be called before the thread gets registered. */
if (EXPECT(NULL == me, FALSE))
return NULL;
# endif
crtn = me->crtn;
nesting_level = crtn->finalizer_nested;
if (nesting_level) {
/* We are inside another GC_invoke_finalizers(). */
/* Skip some implicitly-called GC_invoke_finalizers() */
/* depending on the nesting (recursion) level. */
if ((unsigned)(++crtn->finalizer_skipped) < (1U << nesting_level))
return NULL;
crtn->finalizer_skipped = 0;
}
crtn->finalizer_nested = (unsigned char)(nesting_level + 1);
return &crtn->finalizer_nested;
}
# endif /* !GC_NO_FINALIZATION */
# define ADDR_INSIDE_OBJ(p, obj) \
ADDR_INSIDE(p, (ptr_t)(&(obj)), (ptr_t)(&(obj)) + sizeof(obj))
# if defined(GC_ASSERTIONS) && defined(THREAD_LOCAL_ALLOC)
/* This is called from thread-local GC_malloc(). */
GC_bool
GC_is_thread_tsd_valid(void *tsd)
{
GC_thread me = GC_self_thread();
return ADDR_INSIDE_OBJ((ptr_t)tsd, me->tlfs);
}
# endif /* GC_ASSERTIONS && THREAD_LOCAL_ALLOC */
GC_API int GC_CALL
GC_thread_is_registered(void)
{
/* TODO: Use GC_get_tlfs() instead. */
GC_thread me = GC_self_thread();
return me != NULL && !KNOWN_FINISHED(me);
}
GC_API void GC_CALL
GC_register_altstack(void *normstack, size_t normstack_size, void *altstack,
size_t altstack_size)
{
# ifdef GC_WIN32_THREADS
/* TODO: Implement */
UNUSED_ARG(normstack);
UNUSED_ARG(normstack_size);
UNUSED_ARG(altstack);
UNUSED_ARG(altstack_size);
# else
GC_thread me;
GC_stack_context_t crtn;
READER_LOCK();
me = GC_self_thread_inner();