Module Name: src
Committed By: christos
Date: Wed Nov 21 19:19:25 UTC 2012
Modified Files:
src/lib/libpthread: pthread_int.h pthread_specific.c pthread_tsd.c
Log Message:
Replace the simple implementation of pthread_key_{create,destroy}
and pthread_{g,s}etspecific functions, to one that invalidates
values of keys in other threads when pthread_key_delete() is called.
This fixes chromium, which expects pthread_key_delete() to do
cleanup in all threads.
To generate a diff of this commit:
cvs rdiff -u -r1.87 -r1.88 src/lib/libpthread/pthread_int.h
cvs rdiff -u -r1.23 -r1.24 src/lib/libpthread/pthread_specific.c
cvs rdiff -u -r1.8 -r1.9 src/lib/libpthread/pthread_tsd.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libpthread/pthread_int.h
diff -u src/lib/libpthread/pthread_int.h:1.87 src/lib/libpthread/pthread_int.h:1.88
--- src/lib/libpthread/pthread_int.h:1.87 Sat Nov 3 19:42:27 2012
+++ src/lib/libpthread/pthread_int.h Wed Nov 21 14:19:24 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_int.h,v 1.87 2012/11/03 23:42:27 rmind Exp $ */
+/* $NetBSD: pthread_int.h,v 1.88 2012/11/21 19:19:24 christos Exp $ */
/*-
* Copyright (c) 2001, 2002, 2003, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -148,7 +148,10 @@ struct __pthread_st {
/* Thread-specific data. Large so it sits close to the end. */
int pt_havespecific;
- void *pt_specific[PTHREAD_KEYS_MAX];
+ struct pt_specific {
+ void *pts_value;
+ PTQ_ENTRY(pt_specific) pts_next;
+ } pt_specific[PTHREAD_KEYS_MAX];
/*
* Context for thread creation. At the end as it's cached
@@ -295,6 +298,7 @@ char *pthread__getenv(const char *) PTHR
__dead void pthread__cancelled(void) PTHREAD_HIDE;
void pthread__mutex_deferwake(pthread_t, pthread_mutex_t *) PTHREAD_HIDE;
int pthread__checkpri(int) PTHREAD_HIDE;
+int pthread__add_specific(pthread_t, pthread_key_t, const void *) PTHREAD_HIDE;
#ifndef pthread__smt_pause
#define pthread__smt_pause() /* nothing */
Index: src/lib/libpthread/pthread_specific.c
diff -u src/lib/libpthread/pthread_specific.c:1.23 src/lib/libpthread/pthread_specific.c:1.24
--- src/lib/libpthread/pthread_specific.c:1.23 Wed Sep 12 10:55:48 2012
+++ src/lib/libpthread/pthread_specific.c Wed Nov 21 14:19:24 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_specific.c,v 1.23 2012/09/12 14:55:48 matt Exp $ */
+/* $NetBSD: pthread_specific.c,v 1.24 2012/11/21 19:19:24 christos Exp $ */
/*-
* Copyright (c) 2001, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: pthread_specific.c,v 1.23 2012/09/12 14:55:48 matt Exp $");
+__RCSID("$NetBSD: pthread_specific.c,v 1.24 2012/11/21 19:19:24 christos Exp $");
/* Functions and structures dealing with thread-specific data */
@@ -62,18 +62,14 @@ pthread_setspecific(pthread_key_t key, c
* and return it from functions that are const void *, without
* generating a warning.
*/
- /*LINTED const cast*/
- self->pt_specific[key] = (void *) value;
- self->pt_havespecific = 1;
-
- return 0;
+ return pthread__add_specific(self, key, value);
}
void *
pthread_getspecific(pthread_key_t key)
{
- return pthread__self()->pt_specific[key];
+ return pthread__self()->pt_specific[key].pts_value;
}
unsigned int
Index: src/lib/libpthread/pthread_tsd.c
diff -u src/lib/libpthread/pthread_tsd.c:1.8 src/lib/libpthread/pthread_tsd.c:1.9
--- src/lib/libpthread/pthread_tsd.c:1.8 Fri Mar 2 13:11:53 2012
+++ src/lib/libpthread/pthread_tsd.c Wed Nov 21 14:19:24 2012
@@ -1,4 +1,4 @@
-/* $NetBSD: pthread_tsd.c,v 1.8 2012/03/02 18:11:53 joerg Exp $ */
+/* $NetBSD: pthread_tsd.c,v 1.9 2012/11/21 19:19:24 christos Exp $ */
/*-
* Copyright (c) 2001, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__RCSID("$NetBSD: pthread_tsd.c,v 1.8 2012/03/02 18:11:53 joerg Exp $");
+__RCSID("$NetBSD: pthread_tsd.c,v 1.9 2012/11/21 19:19:24 christos Exp $");
/* Functions and structures dealing with thread-specific data */
#include <errno.h>
@@ -38,14 +38,23 @@ __RCSID("$NetBSD: pthread_tsd.c,v 1.8 20
#include "pthread.h"
#include "pthread_int.h"
+
static pthread_mutex_t tsd_mutex = PTHREAD_MUTEX_INITIALIZER;
static int nextkey;
-void *pthread__tsd_alloc[PTHREAD_KEYS_MAX];
+
+PTQ_HEAD(pthread__tsd_list, pt_specific)
+ pthread__tsd_list[PTHREAD_KEYS_MAX];
void (*pthread__tsd_destructors[PTHREAD_KEYS_MAX])(void *);
__strong_alias(__libc_thr_keycreate,pthread_key_create)
__strong_alias(__libc_thr_keydelete,pthread_key_delete)
+static void
+/*ARGSUSED*/
+null_destructor(void *p)
+{
+}
+
int
pthread_key_create(pthread_key_t *key, void (*destructor)(void *))
{
@@ -54,10 +63,14 @@ pthread_key_create(pthread_key_t *key, v
/* Get a lock on the allocation list */
pthread_mutex_lock(&tsd_mutex);
- /* Find an available slot */
+ /* Find an available slot:
+ * The condition for an available slot is one with the destructor
+ * not being NULL. If the desired destructor is NULL we set it to
+ * our own internal destructor to satisfy the non NULL condition.
+ */
/* 1. Search from "nextkey" to the end of the list. */
for (i = nextkey; i < PTHREAD_KEYS_MAX; i++)
- if (pthread__tsd_alloc[i] == NULL)
+ if (pthread__tsd_destructors[i] == NULL)
break;
if (i == PTHREAD_KEYS_MAX) {
@@ -65,7 +78,7 @@ pthread_key_create(pthread_key_t *key, v
* of the list back to "nextkey".
*/
for (i = 0; i < nextkey; i++)
- if (pthread__tsd_alloc[i] == NULL)
+ if (pthread__tsd_destructors[i] == NULL)
break;
if (i == nextkey) {
@@ -78,15 +91,60 @@ pthread_key_create(pthread_key_t *key, v
}
/* Got one. */
- pthread__tsd_alloc[i] = (void *)__builtin_return_address(0);
+ pthread__assert(PTQ_EMPTY(&pthread__tsd_list[i]));
+ pthread__tsd_destructors[i] = destructor ? destructor : null_destructor;
+
nextkey = (i + 1) % PTHREAD_KEYS_MAX;
- pthread__tsd_destructors[i] = destructor;
pthread_mutex_unlock(&tsd_mutex);
*key = i;
return 0;
}
+/*
+ * Each thread holds an array of PTHREAD_KEYS_MAX pt_specific list
+ * elements. When an element is used it is inserted into the appropriate
+ * key bucket of pthread__tsd_list. This means that ptqe_prev == NULL,
+ * means that the element is not threaded, ptqe_prev != NULL it is
+ * already part of the list. When we set to a NULL value we delete from the
+ * list if it was in the list, and when we set to non-NULL value, we insert
+ * in the list if it was not already there.
+ *
+ * We keep this global array of lists of threads that have called
+ * pthread_set_specific with non-null values, for each key so that
+ * we don't have to check all threads for non-NULL values in
+ * pthread_key_destroy
+ *
+ * We could keep an accounting of the number of specific used
+ * entries per thread, so that we can update pt_havespecific when we delete
+ * the last one, but we don't bother for now
+ */
+int
+pthread__add_specific(pthread_t self, pthread_key_t key, const void *value)
+{
+ struct pt_specific *pt;
+
+ pthread__assert(key >= 0 && key < PTHREAD_KEYS_MAX);
+
+ pthread_mutex_lock(&tsd_mutex);
+ pthread__assert(pthread__tsd_destructors[key] != NULL);
+ pt = &self->pt_specific[key];
+ self->pt_havespecific = 1;
+ if (value) {
+ if (pt->pts_next.ptqe_prev == NULL)
+ PTQ_INSERT_HEAD(&pthread__tsd_list[key], pt, pts_next);
+ } else {
+ if (pt->pts_next.ptqe_prev != NULL) {
+ PTQ_REMOVE(&pthread__tsd_list[key], pt, pts_next);
+ pt->pts_next.ptqe_prev = NULL;
+ }
+ }
+ pt->pts_value = __UNCONST(value);
+ pthread_mutex_unlock(&tsd_mutex);
+
+ return 0;
+}
+
int
pthread_key_delete(pthread_key_t key)
{
@@ -157,8 +215,38 @@ pthread_key_delete(pthread_key_t key)
* apply in general, just to this implementation.
*/
- /* For the momemt, we're going with option 1. */
+ /*
+ * We do option 3; we find the list of all pt_specific structures
+ * threaded on the key we are deleting, unthread them, set the
+ * pointer to NULL, and call the destructor on a saved pointer.
+ * Finally we unthread the entry, freeing it from further use.
+ */
+ struct pt_specific *pt;
+ void (*destructor)(void *);
+
+ pthread__assert(key >= 0 && key < PTHREAD_KEYS_MAX);
+
pthread_mutex_lock(&tsd_mutex);
+
+ pthread__assert(pthread__tsd_destructors[key] != NULL);
+
+ destructor = pthread__tsd_destructors[key];
+ if (destructor == null_destructor)
+ destructor = NULL;
+
+ while ((pt = PTQ_FIRST(&pthread__tsd_list[key])) != NULL) {
+ void *v;
+ PTQ_REMOVE(&pthread__tsd_list[key], pt, pts_next);
+ v = pt->pts_value;
+ pt->pts_value = NULL;
+ pt->pts_next.ptqe_prev = NULL;
+ if (destructor && v) {
+ pthread_mutex_unlock(&tsd_mutex);
+ (*destructor)(v);
+ pthread_mutex_lock(&tsd_mutex);
+ }
+ }
+
pthread__tsd_destructors[key] = NULL;
pthread_mutex_unlock(&tsd_mutex);
@@ -206,17 +294,24 @@ pthread__destroy_tsd(pthread_t self)
do {
done = 1;
for (i = 0; i < PTHREAD_KEYS_MAX; i++) {
- if (self->pt_specific[i] != NULL) {
- pthread_mutex_lock(&tsd_mutex);
+ struct pt_specific *pt = &self->pt_specific[i];
+ if (pt->pts_next.ptqe_prev == NULL)
+ continue;
+ pthread_mutex_lock(&tsd_mutex);
+
+ if (pt->pts_next.ptqe_prev != NULL) {
+ PTQ_REMOVE(&pthread__tsd_list[i], pt, pts_next);
+ val = pt->pts_value;
+ pt->pts_value = NULL;
+ pt->pts_next.ptqe_prev = NULL;
destructor = pthread__tsd_destructors[i];
- pthread_mutex_unlock(&tsd_mutex);
- if (destructor != NULL) {
- done = 0;
- val = self->pt_specific[i];
- /* See above */
- self->pt_specific[i] = NULL;
- (*destructor)(val);
- }
+ } else
+ destructor = NULL;
+
+ pthread_mutex_unlock(&tsd_mutex);
+ if (destructor != NULL) {
+ done = 0;
+ (*destructor)(val);
}
}
} while (!done && iterations--);
