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86aecdfa30032898c1764901aa687dce8ba67e36
w3m/gc/solaris_threads.c
Akinori Ito 6c63633545 Updates from 0.2.1 into 0.2.1-inu-1.5
2001-11-09 04:59:17 +00:00

947 lines
27 KiB
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/*
* Copyright (c) 1994 by Xerox Corporation. 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 for Solaris threads. Provides functionality we wish Sun
* had provided. Relies on some information we probably shouldn't rely on.
*/
/* Boehm, September 14, 1994 4:44 pm PDT */
# if defined(GC_SOLARIS_THREADS) || defined(SOLARIS_THREADS)
# include "private/gc_priv.h"
# include "private/solaris_threads.h"
# include <thread.h>
# include <synch.h>
# include <signal.h>
# include <fcntl.h>
# include <sys/types.h>
# include <sys/mman.h>
# include <sys/time.h>
# include <sys/resource.h>
# include <sys/stat.h>
# include <sys/syscall.h>
# include <sys/procfs.h>
# include <sys/lwp.h>
# include <sys/reg.h>
# define _CLASSIC_XOPEN_TYPES
# include <unistd.h>
# include <errno.h>
/*
* This is the default size of the LWP arrays. If there are more LWPs
* than this when a stop-the-world GC happens, set_max_lwps will be
* called to cope.
* This must be higher than the number of LWPs at startup time.
* The threads library creates a thread early on, so the min. is 3
*/
# define DEFAULT_MAX_LWPS 4
#undef thr_join
#undef thr_create
#undef thr_suspend
#undef thr_continue
cond_t GC_prom_join_cv; /* Broadcast when any thread terminates */
cond_t GC_create_cv; /* Signalled when a new undetached */
/* thread starts. */
#ifdef MMAP_STACKS
static int GC_zfd;
#endif /* MMAP_STACKS */
/* We use the allocation lock to protect thread-related data structures. */
/* We stop the world using /proc primitives. This makes some */
/* minimal assumptions about the threads implementation. */
/* We don't play by the rules, since the rules make this */
/* impossible (as of Solaris 2.3). Also note that as of */
/* Solaris 2.3 the various thread and lwp suspension */
/* primitives failed to stop threads by the time the request */
/* is completed. */
static sigset_t old_mask;
/* Sleep for n milliseconds, n < 1000 */
void GC_msec_sleep(int n)
{
struct timespec ts;
ts.tv_sec = 0;
ts.tv_nsec = 1000000*n;
if (syscall(SYS_nanosleep, &ts, 0) < 0) {
ABORT("nanosleep failed");
}
}
/* Turn off preemption; gross but effective. */
/* Caller has allocation lock. */
/* Actually this is not needed under Solaris 2.3 and */
/* 2.4, but hopefully that'll change. */
void preempt_off()
{
sigset_t set;
(void)sigfillset(&set);
sigdelset(&set, SIGABRT);
syscall(SYS_sigprocmask, SIG_SETMASK, &set, &old_mask);
}
void preempt_on()
{
syscall(SYS_sigprocmask, SIG_SETMASK, &old_mask, NULL);
}
int GC_main_proc_fd = -1;
struct lwp_cache_entry {
lwpid_t lc_id;
int lc_descr; /* /proc file descriptor. */
} GC_lwp_cache_default[DEFAULT_MAX_LWPS];
static int max_lwps = DEFAULT_MAX_LWPS;
static struct lwp_cache_entry *GC_lwp_cache = GC_lwp_cache_default;
static prgregset_t GC_lwp_registers_default[DEFAULT_MAX_LWPS];
static prgregset_t *GC_lwp_registers = GC_lwp_registers_default;
/* Return a file descriptor for the /proc entry corresponding */
/* to the given lwp. The file descriptor may be stale if the */
/* lwp exited and a new one was forked. */
static int open_lwp(lwpid_t id)
{
int result;
static int next_victim = 0;
register int i;
for (i = 0; i < max_lwps; i++) {
if (GC_lwp_cache[i].lc_id == id) return(GC_lwp_cache[i].lc_descr);
}
result = syscall(SYS_ioctl, GC_main_proc_fd, PIOCOPENLWP, &id);
/*
* If PIOCOPENLWP fails, try closing fds in the cache until it succeeds.
*/
if (result < 0 && errno == EMFILE) {
for (i = 0; i < max_lwps; i++) {
if (GC_lwp_cache[i].lc_id != 0) {
(void)syscall(SYS_close, GC_lwp_cache[i].lc_descr);
result = syscall(SYS_ioctl, GC_main_proc_fd, PIOCOPENLWP, &id);
if (result >= 0 || (result < 0 && errno != EMFILE))
break;
}
}
}
if (result < 0) {
if (errno == EMFILE) {
ABORT("Too many open files");
}
return(-1) /* exited? */;
}
if (GC_lwp_cache[next_victim].lc_id != 0)
(void)syscall(SYS_close, GC_lwp_cache[next_victim].lc_descr);
GC_lwp_cache[next_victim].lc_id = id;
GC_lwp_cache[next_victim].lc_descr = result;
if (++next_victim >= max_lwps)
next_victim = 0;
return(result);
}
static void uncache_lwp(lwpid_t id)
{
register int i;
for (i = 0; i < max_lwps; i++) {
if (GC_lwp_cache[i].lc_id == id) {
(void)syscall(SYS_close, GC_lwp_cache[id].lc_descr);
GC_lwp_cache[i].lc_id = 0;
break;
}
}
}
/* Sequence of current lwp ids */
static lwpid_t GC_current_ids_default[DEFAULT_MAX_LWPS + 1];
static lwpid_t *GC_current_ids = GC_current_ids_default;
/* Temporary used below (can be big if large number of LWPs) */
static lwpid_t last_ids_default[DEFAULT_MAX_LWPS + 1];
static lwpid_t *last_ids = last_ids_default;
#define ROUNDUP(n) WORDS_TO_BYTES(ROUNDED_UP_WORDS(n))
static void set_max_lwps(GC_word n)
{
char *mem;
char *oldmem;
int required_bytes = ROUNDUP(n * sizeof(struct lwp_cache_entry))
+ ROUNDUP(n * sizeof(prgregset_t))
+ ROUNDUP((n + 1) * sizeof(lwpid_t))
+ ROUNDUP((n + 1) * sizeof(lwpid_t));
GC_expand_hp_inner(divHBLKSZ((word)required_bytes));
oldmem = mem = GC_scratch_alloc(required_bytes);
if (0 == mem) ABORT("No space for lwp data structures");
/*
* We can either flush the old lwp cache or copy it over. Do the latter.
*/
memcpy(mem, GC_lwp_cache, max_lwps * sizeof(struct lwp_cache_entry));
GC_lwp_cache = (struct lwp_cache_entry*)mem;
mem += ROUNDUP(n * sizeof(struct lwp_cache_entry));
BZERO(GC_lwp_registers, max_lwps * sizeof(GC_lwp_registers[0]));
GC_lwp_registers = (prgregset_t *)mem;
mem += ROUNDUP(n * sizeof(prgregset_t));
GC_current_ids = (lwpid_t *)mem;
mem += ROUNDUP((n + 1) * sizeof(lwpid_t));
last_ids = (lwpid_t *)mem;
mem += ROUNDUP((n + 1)* sizeof(lwpid_t));
if (mem > oldmem + required_bytes)
ABORT("set_max_lwps buffer overflow");
max_lwps = n;
}
/* Stop all lwps in process. Assumes preemption is off. */
/* Caller has allocation lock (and any other locks he may */
/* need). */
static void stop_all_lwps()
{
int lwp_fd;
char buf[30];
prstatus_t status;
register int i;
GC_bool changed;
lwpid_t me = _lwp_self();
if (GC_main_proc_fd == -1) {
sprintf(buf, "/proc/%d", getpid());
GC_main_proc_fd = syscall(SYS_open, buf, O_RDONLY);
if (GC_main_proc_fd < 0) {
if (errno == EMFILE)
ABORT("/proc open failed: too many open files");
GC_printf1("/proc open failed: errno %d", errno);
abort();
}
}
BZERO(GC_lwp_registers, sizeof (prgregset_t) * max_lwps);
for (i = 0; i < max_lwps; i++)
last_ids[i] = 0;
for (;;) {
if (syscall(SYS_ioctl, GC_main_proc_fd, PIOCSTATUS, &status) < 0)
ABORT("Main PIOCSTATUS failed");
if (status.pr_nlwp < 1)
ABORT("Invalid number of lwps returned by PIOCSTATUS");
if (status.pr_nlwp >= max_lwps) {
set_max_lwps(status.pr_nlwp*2 + 10);
/*
* The data in the old GC_current_ids and
* GC_lwp_registers has been trashed. Cleaning out last_ids
* will make sure every LWP gets re-examined.
*/
for (i = 0; i < max_lwps; i++)
last_ids[i] = 0;
continue;
}
if (syscall(SYS_ioctl, GC_main_proc_fd, PIOCLWPIDS, GC_current_ids) < 0)
ABORT("PIOCLWPIDS failed");
changed = FALSE;
for (i = 0; GC_current_ids[i] != 0 && i < max_lwps; i++) {
if (GC_current_ids[i] != last_ids[i]) {
changed = TRUE;
if (GC_current_ids[i] != me) {
/* PIOCSTOP doesn't work without a writable */
/* descriptor. And that makes the process */
/* undebuggable. */
if (_lwp_suspend(GC_current_ids[i]) < 0) {
/* Could happen if the lwp exited */
uncache_lwp(GC_current_ids[i]);
GC_current_ids[i] = me; /* ignore */
}
}
}
}
/*
* In the unlikely event something does a fork between the
* PIOCSTATUS and the PIOCLWPIDS.
*/
if (i >= max_lwps)
continue;
/* All lwps in GC_current_ids != me have been suspended. Note */
/* that _lwp_suspend is idempotent. */
for (i = 0; GC_current_ids[i] != 0; i++) {
if (GC_current_ids[i] != last_ids[i]) {
if (GC_current_ids[i] != me) {
lwp_fd = open_lwp(GC_current_ids[i]);
if (lwp_fd == -1)
{
GC_current_ids[i] = me;
continue;
}
/* LWP should be stopped. Empirically it sometimes */
/* isn't, and more frequently the PR_STOPPED flag */
/* is not set. Wait for PR_STOPPED. */
if (syscall(SYS_ioctl, lwp_fd,
PIOCSTATUS, &status) < 0) {
/* Possible if the descriptor was stale, or */
/* we encountered the 2.3 _lwp_suspend bug. */
uncache_lwp(GC_current_ids[i]);
GC_current_ids[i] = me; /* handle next time. */
} else {
while (!(status.pr_flags & PR_STOPPED)) {
GC_msec_sleep(1);
if (syscall(SYS_ioctl, lwp_fd,
PIOCSTATUS, &status) < 0) {
ABORT("Repeated PIOCSTATUS failed");
}
if (status.pr_flags & PR_STOPPED) break;
GC_msec_sleep(20);
if (syscall(SYS_ioctl, lwp_fd,
PIOCSTATUS, &status) < 0) {
ABORT("Repeated PIOCSTATUS failed");
}
}
if (status.pr_who != GC_current_ids[i]) {
/* can happen if thread was on death row */
uncache_lwp(GC_current_ids[i]);
GC_current_ids[i] = me; /* handle next time. */
continue;
}
/* Save registers where collector can */
/* find them. */
BCOPY(status.pr_reg, GC_lwp_registers[i],
sizeof (prgregset_t));
}
}
}
}
if (!changed) break;
for (i = 0; i < max_lwps; i++) last_ids[i] = GC_current_ids[i];
}
}
/* Restart all lwps in process. Assumes preemption is off. */
static void restart_all_lwps()
{
int lwp_fd;
register int i;
GC_bool changed;
lwpid_t me = _lwp_self();
# define PARANOID
for (i = 0; GC_current_ids[i] != 0; i++) {
# ifdef PARANOID
if (GC_current_ids[i] != me) {
int lwp_fd = open_lwp(GC_current_ids[i]);
prstatus_t status;
if (lwp_fd < 0) ABORT("open_lwp failed");
if (syscall(SYS_ioctl, lwp_fd,
PIOCSTATUS, &status) < 0) {
ABORT("PIOCSTATUS failed in restart_all_lwps");
}
if (memcmp(status.pr_reg, GC_lwp_registers[i],
sizeof (prgregset_t)) != 0) {
int j;
for(j = 0; j < NGREG; j++)
{
GC_printf3("%i: %x -> %x\n", j,
GC_lwp_registers[i][j],
status.pr_reg[j]);
}
ABORT("Register contents changed");
}
if (!status.pr_flags & PR_STOPPED) {
ABORT("lwp no longer stopped");
}
#ifdef SPARC
{
gwindows_t windows;
if (syscall(SYS_ioctl, lwp_fd,
PIOCGWIN, &windows) < 0) {
ABORT("PIOCSTATUS failed in restart_all_lwps");
}
if (windows.wbcnt > 0) ABORT("unsaved register windows");
}
#endif
}
# endif /* PARANOID */
if (GC_current_ids[i] == me) continue;
if (_lwp_continue(GC_current_ids[i]) < 0) {
ABORT("Failed to restart lwp");
}
}
if (i >= max_lwps) ABORT("Too many lwps");
}
GC_bool GC_multithreaded = 0;
void GC_stop_world()
{
preempt_off();
if (GC_multithreaded)
stop_all_lwps();
}
void GC_start_world()
{
if (GC_multithreaded)
restart_all_lwps();
preempt_on();
}
void GC_thr_init(void);
GC_bool GC_thr_initialized = FALSE;
size_t GC_min_stack_sz;
size_t GC_page_sz;
/*
* stack_head is stored at the top of free stacks
*/
struct stack_head {
struct stack_head *next;
ptr_t base;
thread_t owner;
};
# define N_FREE_LISTS 25
struct stack_head *GC_stack_free_lists[N_FREE_LISTS] = { 0 };
/* GC_stack_free_lists[i] is free list for stacks of */
/* size GC_min_stack_sz*2**i. */
/* Free lists are linked through stack_head stored */ /* at top of stack. */
/* Return a stack of size at least *stack_size. *stack_size is */
/* replaced by the actual stack size. */
/* Caller holds allocation lock. */
ptr_t GC_stack_alloc(size_t * stack_size)
{
register size_t requested_sz = *stack_size;
register size_t search_sz = GC_min_stack_sz;
register int index = 0; /* = log2(search_sz/GC_min_stack_sz) */
register ptr_t base;
register struct stack_head *result;
while (search_sz < requested_sz) {
search_sz *= 2;
index++;
}
if ((result = GC_stack_free_lists[index]) == 0
&& (result = GC_stack_free_lists[index+1]) != 0) {
/* Try next size up. */
search_sz *= 2; index++;
}
if (result != 0) {
base = GC_stack_free_lists[index]->base;
GC_stack_free_lists[index] = GC_stack_free_lists[index]->next;
} else {
#ifdef MMAP_STACKS
base = (ptr_t)mmap(0, search_sz + GC_page_sz,
PROT_READ|PROT_WRITE, MAP_PRIVATE |MAP_NORESERVE,
GC_zfd, 0);
if (base == (ptr_t)-1)
{
*stack_size = 0;
return NULL;
}
mprotect(base, GC_page_sz, PROT_NONE);
/* Should this use divHBLKSZ(search_sz + GC_page_sz) ? -- cf */
GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));
base += GC_page_sz;
#else
base = (ptr_t) GC_scratch_alloc(search_sz + 2*GC_page_sz);
if (base == NULL)
{
*stack_size = 0;
return NULL;
}
base = (ptr_t)(((word)base + GC_page_sz) & ~(GC_page_sz - 1));
/* Protect hottest page to detect overflow. */
# ifdef SOLARIS23_MPROTECT_BUG_FIXED
mprotect(base, GC_page_sz, PROT_NONE);
# endif
GC_is_fresh((struct hblk *)base, divHBLKSZ(search_sz));
base += GC_page_sz;
#endif
}
*stack_size = search_sz;
return(base);
}
/* Caller holds allocationlock. */
void GC_stack_free(ptr_t stack, size_t size)
{
register int index = 0;
register size_t search_sz = GC_min_stack_sz;
register struct stack_head *head;
#ifdef MMAP_STACKS
/* Zero pointers */
mmap(stack, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_NORESERVE|MAP_FIXED,
GC_zfd, 0);
#endif
while (search_sz < size) {
search_sz *= 2;
index++;
}
if (search_sz != size) ABORT("Bad stack size");
head = (struct stack_head *)(stack + search_sz - sizeof(struct stack_head));
head->next = GC_stack_free_lists[index];
head->base = stack;
GC_stack_free_lists[index] = head;
}
void GC_my_stack_limits();
/* Notify virtual dirty bit implementation that known empty parts of */
/* stacks do not contain useful data. */
/* Caller holds allocation lock. */
void GC_old_stacks_are_fresh()
{
/* No point in doing this for MMAP stacks - and pointers are zero'd out */
/* by the mmap in GC_stack_free */
#ifndef MMAP_STACKS
register int i;
register struct stack_head *s;
register ptr_t p;
register size_t sz;
register struct hblk * h;
int dummy;
for (i = 0, sz= GC_min_stack_sz; i < N_FREE_LISTS;
i++, sz *= 2) {
for (s = GC_stack_free_lists[i]; s != 0; s = s->next) {
p = s->base;
h = (struct hblk *)(((word)p + HBLKSIZE-1) & ~(HBLKSIZE-1));
if ((ptr_t)h == p) {
GC_is_fresh((struct hblk *)p, divHBLKSZ(sz));
} else {
GC_is_fresh((struct hblk *)p, divHBLKSZ(sz) - 1);
BZERO(p, (ptr_t)h - p);
}
}
}
#endif /* MMAP_STACKS */
GC_my_stack_limits();
}
/* The set of all known threads. We intercept thread creation and */
/* joins. We never actually create detached threads. We allocate all */
/* new thread stacks ourselves. These allow us to maintain this */
/* data structure. */
# define THREAD_TABLE_SZ 128 /* Must be power of 2 */
volatile GC_thread GC_threads[THREAD_TABLE_SZ];
void GC_push_thread_structures GC_PROTO((void))
{
GC_push_all((ptr_t)(GC_threads), (ptr_t)(GC_threads)+sizeof(GC_threads));
}
/* Add a thread to GC_threads. We assume it wasn't already there. */
/* Caller holds allocation lock. */
GC_thread GC_new_thread(thread_t id)
{
int hv = ((word)id) % THREAD_TABLE_SZ;
GC_thread result;
static struct GC_Thread_Rep first_thread;
static GC_bool first_thread_used = FALSE;
if (!first_thread_used) {
result = &first_thread;
first_thread_used = TRUE;
/* Dont acquire allocation lock, since we may already hold it. */
} else {
result = (struct GC_Thread_Rep *)
GC_INTERNAL_MALLOC(sizeof(struct GC_Thread_Rep), NORMAL);
}
if (result == 0) return(0);
result -> id = id;
result -> next = GC_threads[hv];
GC_threads[hv] = result;
/* result -> finished = 0; */
(void) cond_init(&(result->join_cv), USYNC_THREAD, 0);
return(result);
}
/* Delete a thread from GC_threads. We assume it is there. */
/* (The code intentionally traps if it wasn't.) */
/* Caller holds allocation lock. */
void GC_delete_thread(thread_t id)
{
int hv = ((word)id) % THREAD_TABLE_SZ;
register GC_thread p = GC_threads[hv];
register GC_thread prev = 0;
while (p -> id != id) {
prev = p;
p = p -> next;
}
if (prev == 0) {
GC_threads[hv] = p -> next;
} else {
prev -> next = p -> next;
}
}
/* Return the GC_thread correpsonding to a given thread_t. */
/* Returns 0 if it's not there. */
/* Caller holds allocation lock. */
GC_thread GC_lookup_thread(thread_t id)
{
int hv = ((word)id) % THREAD_TABLE_SZ;
register GC_thread p = GC_threads[hv];
while (p != 0 && p -> id != id) p = p -> next;
return(p);
}
# define MAX_ORIG_STACK_SIZE (8 * 1024 * 1024)
word GC_get_orig_stack_size() {
struct rlimit rl;
static int warned = 0;
int result;
if (getrlimit(RLIMIT_STACK, &rl) != 0) ABORT("getrlimit failed");
result = (word)rl.rlim_cur & ~(HBLKSIZE-1);
if (result > MAX_ORIG_STACK_SIZE) {
if (!warned) {
WARN("Large stack limit(%ld): only scanning 8 MB\n", result);
warned = 1;
}
result = MAX_ORIG_STACK_SIZE;
}
return result;
}
/* Notify dirty bit implementation of unused parts of my stack. */
/* Caller holds allocation lock. */
void GC_my_stack_limits()
{
int dummy;
register ptr_t hottest = (ptr_t)((word)(&dummy) & ~(HBLKSIZE-1));
register GC_thread me = GC_lookup_thread(thr_self());
register size_t stack_size = me -> stack_size;
register ptr_t stack;
if (stack_size == 0) {
/* original thread */
/* Empirically, what should be the stack page with lowest */
/* address is actually inaccessible. */
stack_size = GC_get_orig_stack_size() - GC_page_sz;
stack = GC_stackbottom - stack_size + GC_page_sz;
} else {
stack = me -> stack;
}
if (stack > hottest || stack + stack_size < hottest) {
ABORT("sp out of bounds");
}
GC_is_fresh((struct hblk *)stack, divHBLKSZ(hottest - stack));
}
/* We hold allocation lock. Should do exactly the right thing if the */
/* world is stopped. Should not fail if it isn't. */
void GC_push_all_stacks()
{
register int i;
register GC_thread p;
register ptr_t sp = GC_approx_sp();
register ptr_t bottom, top;
struct rlimit rl;
# define PUSH(bottom,top) \
if (GC_dirty_maintained) { \
GC_push_selected((bottom), (top), GC_page_was_ever_dirty, \
GC_push_all_stack); \
} else { \
GC_push_all_stack((bottom), (top)); \
}
GC_push_all_stack((ptr_t)GC_lwp_registers,
(ptr_t)GC_lwp_registers
+ max_lwps * sizeof(GC_lwp_registers[0]));
for (i = 0; i < THREAD_TABLE_SZ; i++) {
for (p = GC_threads[i]; p != 0; p = p -> next) {
if (p -> stack_size != 0) {
bottom = p -> stack;
top = p -> stack + p -> stack_size;
} else {
/* The original stack. */
bottom = GC_stackbottom - GC_get_orig_stack_size() + GC_page_sz;
top = GC_stackbottom;
}
if ((word)sp > (word)bottom && (word)sp < (word)top) bottom = sp;
PUSH(bottom, top);
}
}
}
int GC_is_thread_stack(ptr_t addr)
{
register int i;
register GC_thread p;
register ptr_t bottom, top;
for (i = 0; i < THREAD_TABLE_SZ; i++) {
for (p = GC_threads[i]; p != 0; p = p -> next) {
if (p -> stack_size != 0) {
if (p -> stack <= addr &&
addr < p -> stack + p -> stack_size)
return 1;
}
}
}
return 0;
}
/* The only thread that ever really performs a thr_join. */
void * GC_thr_daemon(void * dummy)
{
void *status;
thread_t departed;
register GC_thread t;
register int i;
register int result;
for(;;) {
start:
result = thr_join((thread_t)0, &departed, &status);
LOCK();
if (result != 0) {
/* No more threads; wait for create. */
for (i = 0; i < THREAD_TABLE_SZ; i++) {
for (t = GC_threads[i]; t != 0; t = t -> next) {
if (!(t -> flags & (DETACHED | FINISHED))) {
UNLOCK();
goto start; /* Thread started just before we */
/* acquired the lock. */
}
}
}
cond_wait(&GC_create_cv, &GC_allocate_ml);
UNLOCK();
} else {
t = GC_lookup_thread(departed);
GC_multithreaded--;
if (!(t -> flags & CLIENT_OWNS_STACK)) {
GC_stack_free(t -> stack, t -> stack_size);
}
if (t -> flags & DETACHED) {
GC_delete_thread(departed);
} else {
t -> status = status;
t -> flags |= FINISHED;
cond_signal(&(t -> join_cv));
cond_broadcast(&GC_prom_join_cv);
}
UNLOCK();
}
}
}
/* We hold the allocation lock, or caller ensures that 2 instances */
/* cannot be invoked concurrently. */
void GC_thr_init(void)
{
GC_thread t;
thread_t tid;
if (GC_thr_initialized)
return;
GC_thr_initialized = TRUE;
GC_min_stack_sz = ((thr_min_stack() + 32*1024 + HBLKSIZE-1)
& ~(HBLKSIZE - 1));
GC_page_sz = sysconf(_SC_PAGESIZE);
#ifdef MMAP_STACKS
GC_zfd = open("/dev/zero", O_RDONLY);
if (GC_zfd == -1)
ABORT("Can't open /dev/zero");
#endif /* MMAP_STACKS */
cond_init(&GC_prom_join_cv, USYNC_THREAD, 0);
cond_init(&GC_create_cv, USYNC_THREAD, 0);
/* Add the initial thread, so we can stop it. */
t = GC_new_thread(thr_self());
t -> stack_size = 0;
t -> flags = DETACHED | CLIENT_OWNS_STACK;
if (thr_create(0 /* stack */, 0 /* stack_size */, GC_thr_daemon,
0 /* arg */, THR_DETACHED | THR_DAEMON,
&tid /* thread_id */) != 0) {
ABORT("Cant fork daemon");
}
thr_setprio(tid, 126);
}
/* We acquire the allocation lock to prevent races with */
/* stopping/starting world. */
/* This is no more correct than the underlying Solaris 2.X */
/* implementation. Under 2.3 THIS IS BROKEN. */
int GC_thr_suspend(thread_t target_thread)
{
GC_thread t;
int result;
LOCK();
result = thr_suspend(target_thread);
if (result == 0) {
t = GC_lookup_thread(target_thread);
if (t == 0) ABORT("thread unknown to GC");
t -> flags |= SUSPENDED;
}
UNLOCK();
return(result);
}
int GC_thr_continue(thread_t target_thread)
{
GC_thread t;
int result;
LOCK();
result = thr_continue(target_thread);
if (result == 0) {
t = GC_lookup_thread(target_thread);
if (t == 0) ABORT("thread unknown to GC");
t -> flags &= ~SUSPENDED;
}
UNLOCK();
return(result);
}
int GC_thr_join(thread_t wait_for, thread_t *departed, void **status)
{
register GC_thread t;
int result = 0;
LOCK();
if (wait_for == 0) {
register int i;
register GC_bool thread_exists;
for (;;) {
thread_exists = FALSE;
for (i = 0; i < THREAD_TABLE_SZ; i++) {
for (t = GC_threads[i]; t != 0; t = t -> next) {
if (!(t -> flags & DETACHED)) {
if (t -> flags & FINISHED) {
goto found;
}
thread_exists = TRUE;
}
}
}
if (!thread_exists) {
result = ESRCH;
goto out;
}
cond_wait(&GC_prom_join_cv, &GC_allocate_ml);
}
} else {
t = GC_lookup_thread(wait_for);
if (t == 0 || t -> flags & DETACHED) {
result = ESRCH;
goto out;
}
if (wait_for == thr_self()) {
result = EDEADLK;
goto out;
}
while (!(t -> flags & FINISHED)) {
cond_wait(&(t -> join_cv), &GC_allocate_ml);
}
}
found:
if (status) *status = t -> status;
if (departed) *departed = t -> id;
cond_destroy(&(t -> join_cv));
GC_delete_thread(t -> id);
out:
UNLOCK();
return(result);
}
int
GC_thr_create(void *stack_base, size_t stack_size,
void *(*start_routine)(void *), void *arg, long flags,
thread_t *new_thread)
{
int result;
GC_thread t;
thread_t my_new_thread;
word my_flags = 0;
void * stack = stack_base;
LOCK();
if (!GC_thr_initialized)
{
GC_thr_init();
}
GC_multithreaded++;
if (stack == 0) {
if (stack_size == 0) stack_size = 1024*1024;
stack = (void *)GC_stack_alloc(&stack_size);
if (stack == 0) {
GC_multithreaded--;
UNLOCK();
return(ENOMEM);
}
} else {
my_flags |= CLIENT_OWNS_STACK;
}
if (flags & THR_DETACHED) my_flags |= DETACHED;
if (flags & THR_SUSPENDED) my_flags |= SUSPENDED;
result = thr_create(stack, stack_size, start_routine,
arg, flags & ~THR_DETACHED, &my_new_thread);
if (result == 0) {
t = GC_new_thread(my_new_thread);
t -> flags = my_flags;
if (!(my_flags & DETACHED)) cond_init(&(t -> join_cv), USYNC_THREAD, 0);
t -> stack = stack;
t -> stack_size = stack_size;
if (new_thread != 0) *new_thread = my_new_thread;
cond_signal(&GC_create_cv);
} else {
GC_multithreaded--;
if (!(my_flags & CLIENT_OWNS_STACK)) {
GC_stack_free(stack, stack_size);
}
}
UNLOCK();
return(result);
}
# else /* SOLARIS_THREADS */
#ifndef LINT
int GC_no_sunOS_threads;
#endif
#endif
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