svn commit: r201546 - in head: . include lib/libc/gen
lib/libc/include lib/libthr lib/libthr/thread sys/kern sys/sys
David Xu
davidxu at FreeBSD.org
Tue Jan 5 02:37:59 UTC 2010
Author: davidxu
Date: Tue Jan 5 02:37:59 2010
New Revision: 201546
URL: http://svn.freebsd.org/changeset/base/201546
Log:
Use umtx to implement process sharable semaphore, to make this work,
now type sema_t is a structure which can be put in a shared memory area,
and multiple processes can operate it concurrently.
User can either use mmap(MAP_SHARED) + sem_init(pshared=1) or use sem_open()
to initialize a shared semaphore.
Named semaphore uses file system and is located in /tmp directory, and its
file name is prefixed with 'SEMD', so now it is chroot or jail friendly.
In simplist cases, both for named and un-named semaphore, userland code
does not have to enter kernel to reduce/increase semaphore's count.
The semaphore is designed to be crash-safe, it means even if an application
is crashed in the middle of operating semaphore, the semaphore state is
still safely recovered by later use, there is no waiter counter maintained
by userland code.
The main semaphore code is in libc and libthr only has some necessary stubs,
this makes it possible that a non-threaded application can use semaphore
without linking to thread library.
Old semaphore implementation is kept libc to maintain binary compatibility.
The kernel ksem API is no longer used in the new implemenation.
Discussed on: threads@
Added:
head/include/semaphore.h (contents, props changed)
head/lib/libc/gen/sem_new.c (contents, props changed)
head/lib/libthr/thread/thr_sem_new.c (contents, props changed)
Deleted:
head/sys/sys/semaphore.h
Modified:
head/ObsoleteFiles.inc
head/include/Makefile
head/lib/libc/gen/Makefile.inc
head/lib/libc/gen/Symbol.map
head/lib/libc/gen/_pthread_stubs.c
head/lib/libc/gen/sem.c
head/lib/libc/include/libc_private.h
head/lib/libthr/pthread.map
head/lib/libthr/thread/Makefile.inc
head/lib/libthr/thread/thr_init.c
head/lib/libthr/thread/thr_private.h
head/lib/libthr/thread/thr_sem.c
head/sys/kern/uipc_sem.c
head/sys/sys/_semaphore.h
Modified: head/ObsoleteFiles.inc
==============================================================================
--- head/ObsoleteFiles.inc Tue Jan 5 02:06:05 2010 (r201545)
+++ head/ObsoleteFiles.inc Tue Jan 5 02:37:59 2010 (r201546)
@@ -14,6 +14,8 @@
# The file is partitioned: OLD_FILES first, then OLD_LIBS and OLD_DIRS last.
#
+# 20100105: new userland semaphore implementation
+OLD_FILES+=usr/include/sys/semaphore.h
# 20100103: ntptrace(8) removed
OLD_FILES+=usr/sbin/ntptrace
OLD_FILES+=usr/share/man/man8/ntptrace.8.gz
Modified: head/include/Makefile
==============================================================================
--- head/include/Makefile Tue Jan 5 02:06:05 2010 (r201545)
+++ head/include/Makefile Tue Jan 5 02:37:59 2010 (r201546)
@@ -18,7 +18,7 @@ INCS= a.out.h ar.h assert.h bitstring.h
netdb.h nl_types.h nlist.h nss.h nsswitch.h paths.h \
printf.h proc_service.h pthread.h \
pthread_np.h pwd.h ranlib.h readpassphrase.h regex.h regexp.h \
- res_update.h resolv.h runetype.h search.h setjmp.h \
+ res_update.h resolv.h runetype.h search.h semaphore.h setjmp.h \
signal.h spawn.h stab.h \
stdbool.h stddef.h stdio.h stdlib.h string.h stringlist.h \
strings.h sysexits.h tar.h termios.h tgmath.h \
@@ -28,7 +28,7 @@ INCS= a.out.h ar.h assert.h bitstring.h
MHDRS= float.h floatingpoint.h stdarg.h
-PHDRS= sched.h semaphore.h _semaphore.h
+PHDRS= sched.h _semaphore.h
LHDRS= aio.h errno.h fcntl.h linker_set.h poll.h stdint.h syslog.h \
ucontext.h
Added: head/include/semaphore.h
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/include/semaphore.h Tue Jan 5 02:37:59 2010 (r201546)
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2010 David Xu <davidxu at freebsd.org>
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice unmodified, this list of conditions, and the following
+ * disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/* semaphore.h: POSIX 1003.1b semaphores */
+
+#ifndef _SEMAPHORE_H_
+#define _SEMAPHORE_H_
+
+#include <sys/cdefs.h>
+#include <sys/_types.h>
+#include <sys/_umtx.h>
+
+struct _sem {
+ __uint32_t _magic;
+ struct _usem _kern;
+};
+
+typedef struct _sem sem_t;
+
+#define SEM_FAILED ((sem_t *)0)
+#define SEM_VALUE_MAX __INT_MAX
+
+struct timespec;
+
+__BEGIN_DECLS
+int sem_close(sem_t *);
+int sem_destroy(sem_t *);
+int sem_getvalue(sem_t * __restrict, int * __restrict);
+int sem_init(sem_t *, int, unsigned int);
+sem_t *sem_open(const char *, int, ...);
+int sem_post(sem_t *);
+int sem_timedwait(sem_t * __restrict, const struct timespec * __restrict);
+int sem_trywait(sem_t *);
+int sem_unlink(const char *);
+int sem_wait(sem_t *);
+__END_DECLS
+
+#endif /* !_SEMAPHORE_H_ */
Modified: head/lib/libc/gen/Makefile.inc
==============================================================================
--- head/lib/libc/gen/Makefile.inc Tue Jan 5 02:06:05 2010 (r201545)
+++ head/lib/libc/gen/Makefile.inc Tue Jan 5 02:37:59 2010 (r201546)
@@ -25,7 +25,7 @@ SRCS+= __getosreldate.c __xuname.c \
pause.c pmadvise.c popen.c posix_spawn.c \
psignal.c pw_scan.c pwcache.c \
raise.c readdir.c readpassphrase.c rewinddir.c \
- scandir.c seed48.c seekdir.c sem.c semctl.c \
+ scandir.c seed48.c seekdir.c sem.c sem_new.c semctl.c \
setdomainname.c sethostname.c setjmperr.c setmode.c \
setproctitle.c setprogname.c siginterrupt.c siglist.c signal.c \
sigsetops.c sleep.c srand48.c statvfs.c stringlist.c strtofflags.c \
Modified: head/lib/libc/gen/Symbol.map
==============================================================================
--- head/lib/libc/gen/Symbol.map Tue Jan 5 02:06:05 2010 (r201545)
+++ head/lib/libc/gen/Symbol.map Tue Jan 5 02:37:59 2010 (r201546)
@@ -236,16 +236,6 @@ FBSD_1.0 {
seekdir;
user_from_uid;
group_from_gid;
- sem_init;
- sem_destroy;
- sem_open;
- sem_close;
- sem_unlink;
- sem_wait;
- sem_trywait;
- sem_timedwait;
- sem_post;
- sem_getvalue;
setdomainname;
sethostname;
longjmperror;
@@ -363,11 +353,23 @@ FBSD_1.1 {
semctl;
tcgetsid;
tcsetsid;
+ __pthread_cleanup_pop_imp;
+ __pthread_cleanup_push_imp;
};
FBSD_1.2 {
basename_r;
getpagesizes;
+ sem_close;
+ sem_destroy;
+ sem_getvalue;
+ sem_init;
+ sem_open;
+ sem_timedwait;
+ sem_trywait;
+ sem_post;
+ sem_wait;
+ sem_unlink;
};
FBSDprivate_1.0 {
@@ -456,16 +458,6 @@ FBSDprivate_1.0 {
__pw_scan; /* Used by (at least) libutil */
__raise;
_raise;
- __sem_init;
- __sem_destroy;
- __sem_open;
- __sem_close;
- __sem_unlink;
- __sem_wait;
- __sem_trywait;
- __sem_timedwait;
- __sem_post;
- __sem_getvalue;
__sleep;
_sleep;
_rtld_allocate_tls;
@@ -482,4 +474,23 @@ FBSDprivate_1.0 {
_wait;
__waitpid;
_waitpid;
+
+ _libc_sem_destroy;
+ _libc_sem_init;
+ _libc_sem_getvalue;
+ _libc_sem_trywait;
+ _libc_sem_wait;
+ _libc_sem_timedwait;
+ _libc_sem_post;
+
+ _libc_sem_init_compat;
+ _libc_sem_destroy_compat;
+ _libc_sem_open_compat;
+ _libc_sem_close_compat;
+ _libc_sem_unlink_compat;
+ _libc_sem_wait_compat;
+ _libc_sem_trywait_compat;
+ _libc_sem_timedwait_compat;
+ _libc_sem_post_compat;
+ _libc_sem_getvalue_compat;
};
Modified: head/lib/libc/gen/_pthread_stubs.c
==============================================================================
--- head/lib/libc/gen/_pthread_stubs.c Tue Jan 5 02:06:05 2010 (r201545)
+++ head/lib/libc/gen/_pthread_stubs.c Tue Jan 5 02:37:59 2010 (r201546)
@@ -119,6 +119,8 @@ pthread_func_entry_t __thr_jtable[PJT_MA
{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_SETSPECIFIC */
{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_SIGMASK */
{PJT_DUAL_ENTRY(stub_zero)}, /* PJT_TESTCANCEL */
+ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CLEANUP_POP_IMP */
+ {PJT_DUAL_ENTRY(stub_zero)}, /* PJT_CLEANUP_PUSH_IMP */
};
/*
@@ -265,6 +267,8 @@ STUB_FUNC2(pthread_kill, PJT_KILL, int,
STUB_FUNC2(pthread_setcancelstate, PJT_SETCANCELSTATE, int, int, void *)
STUB_FUNC2(pthread_setcanceltype, PJT_SETCANCELTYPE, int, int, void *)
STUB_FUNC(pthread_testcancel, PJT_TESTCANCEL, void)
+STUB_FUNC1(__pthread_cleanup_pop_imp, PJT_CLEANUP_POP_IMP, int, int)
+STUB_FUNC2(__pthread_cleanup_push_imp, PJT_CLEANUP_PUSH_IMP, void, void*, void *);
static int
stub_zero(void)
Modified: head/lib/libc/gen/sem.c
==============================================================================
--- head/lib/libc/gen/sem.c Tue Jan 5 02:06:05 2010 (r201545)
+++ head/lib/libc/gen/sem.c Tue Jan 5 02:37:59 2010 (r201546)
@@ -1,4 +1,5 @@
/*
+ * Copyright (C) 2010 David Xu <davidxu at freebsd.org>.
* Copyright (C) 2000 Jason Evans <jasone at freebsd.org>.
* All rights reserved.
*
@@ -59,34 +60,71 @@
#include "namespace.h"
#include <sys/types.h>
#include <sys/queue.h>
+#include <machine/atomic.h>
#include <errno.h>
+#include <sys/umtx.h>
+#include <sys/_semaphore.h>
+#include <limits.h>
#include <fcntl.h>
#include <pthread.h>
-#include <semaphore.h>
#include <stdarg.h>
#include <stdlib.h>
#include <time.h>
-#include <_semaphore.h>
#include "un-namespace.h"
#include "libc_private.h"
+/*
+ * Old semaphore definitions.
+ */
+struct sem {
+#define SEM_MAGIC ((u_int32_t) 0x09fa4012)
+ u_int32_t magic;
+ pthread_mutex_t lock;
+ pthread_cond_t gtzero;
+ u_int32_t count;
+ u_int32_t nwaiters;
+#define SEM_USER (NULL)
+ semid_t semid; /* semaphore id if kernel (shared) semaphore */
+ int syssem; /* 1 if kernel (shared) semaphore */
+ LIST_ENTRY(sem) entry;
+ struct sem **backpointer;
+};
+
+typedef struct sem* sem_t;
+
+#define SEM_FAILED ((sem_t *)0)
+#define SEM_VALUE_MAX __INT_MAX
+
+#define SYM_FB10(sym) __CONCAT(sym, _fb10)
+#define SYM_FBP10(sym) __CONCAT(sym, _fbp10)
+#define WEAK_REF(sym, alias) __weak_reference(sym, alias)
+#define SYM_COMPAT(sym, impl, ver) __sym_compat(sym, impl, ver)
+#define SYM_DEFAULT(sym, impl, ver) __sym_default(sym, impl, ver)
+
+#define FB10_COMPAT(func, sym) \
+ WEAK_REF(func, SYM_FB10(sym)); \
+ SYM_COMPAT(sym, SYM_FB10(sym), FBSD_1.0)
+
+#define FB10_COMPAT_PRIVATE(func, sym) \
+ WEAK_REF(func, SYM_FBP10(sym)); \
+ SYM_DEFAULT(sym, SYM_FBP10(sym), FBSDprivate_1.0)
+
static sem_t sem_alloc(unsigned int value, semid_t semid, int system_sem);
static void sem_free(sem_t sem);
-static LIST_HEAD(, sem) named_sems = LIST_HEAD_INITIALIZER(named_sems);
+static LIST_HEAD(, sem) named_sems = LIST_HEAD_INITIALIZER(&named_sems);
static pthread_mutex_t named_sems_mtx = PTHREAD_MUTEX_INITIALIZER;
-__weak_reference(__sem_init, sem_init);
-__weak_reference(__sem_destroy, sem_destroy);
-__weak_reference(__sem_open, sem_open);
-__weak_reference(__sem_close, sem_close);
-__weak_reference(__sem_unlink, sem_unlink);
-__weak_reference(__sem_wait, sem_wait);
-__weak_reference(__sem_trywait, sem_trywait);
-__weak_reference(__sem_timedwait, sem_timedwait);
-__weak_reference(__sem_post, sem_post);
-__weak_reference(__sem_getvalue, sem_getvalue);
-
+FB10_COMPAT(_libc_sem_init_compat, sem_init);
+FB10_COMPAT(_libc_sem_destroy_compat, sem_destroy);
+FB10_COMPAT(_libc_sem_open_compat, sem_open);
+FB10_COMPAT(_libc_sem_close_compat, sem_close);
+FB10_COMPAT(_libc_sem_unlink_compat, sem_unlink);
+FB10_COMPAT(_libc_sem_wait_compat, sem_wait);
+FB10_COMPAT(_libc_sem_trywait_compat, sem_trywait);
+FB10_COMPAT(_libc_sem_timedwait_compat, sem_timedwait);
+FB10_COMPAT(_libc_sem_post_compat, sem_post);
+FB10_COMPAT(_libc_sem_getvalue_compat, sem_getvalue);
static inline int
sem_check_validity(sem_t *sem)
@@ -104,8 +142,6 @@ static void
sem_free(sem_t sem)
{
- _pthread_mutex_destroy(&sem->lock);
- _pthread_cond_destroy(&sem->gtzero);
sem->magic = 0;
free(sem);
}
@@ -131,13 +167,11 @@ sem_alloc(unsigned int value, semid_t se
sem->magic = SEM_MAGIC;
sem->semid = semid;
sem->syssem = system_sem;
- sem->lock = PTHREAD_MUTEX_INITIALIZER;
- sem->gtzero = PTHREAD_COND_INITIALIZER;
return (sem);
}
int
-__sem_init(sem_t *sem, int pshared, unsigned int value)
+_libc_sem_init_compat(sem_t *sem, int pshared, unsigned int value)
{
semid_t semid;
@@ -147,26 +181,27 @@ __sem_init(sem_t *sem, int pshared, unsi
* pthread_cond_wait() is just a stub that doesn't really
* wait.
*/
- if (ksem_init(&semid, value) != 0)
+ semid = (semid_t)SEM_USER;
+ if ((pshared != 0) && ksem_init(&semid, value) != 0)
return (-1);
- (*sem) = sem_alloc(value, semid, 1);
+ *sem = sem_alloc(value, semid, pshared);
if ((*sem) == NULL) {
- ksem_destroy(semid);
+ if (pshared != 0)
+ ksem_destroy(semid);
return (-1);
}
return (0);
}
int
-__sem_destroy(sem_t *sem)
+_libc_sem_destroy_compat(sem_t *sem)
{
int retval;
if (sem_check_validity(sem) != 0)
return (-1);
- _pthread_mutex_lock(&(*sem)->lock);
/*
* If this is a system semaphore let the kernel track it otherwise
* make sure there are no waiters.
@@ -181,18 +216,14 @@ __sem_destroy(sem_t *sem)
retval = 0;
(*sem)->magic = 0;
}
- _pthread_mutex_unlock(&(*sem)->lock);
- if (retval == 0) {
- _pthread_mutex_destroy(&(*sem)->lock);
- _pthread_cond_destroy(&(*sem)->gtzero);
+ if (retval == 0)
sem_free(*sem);
- }
return (retval);
}
sem_t *
-__sem_open(const char *name, int oflag, ...)
+_libc_sem_open_compat(const char *name, int oflag, ...)
{
sem_t *sem;
sem_t s;
@@ -255,7 +286,7 @@ err:
}
int
-__sem_close(sem_t *sem)
+_libc_sem_close_compat(sem_t *sem)
{
if (sem_check_validity(sem) != 0)
@@ -280,68 +311,156 @@ __sem_close(sem_t *sem)
}
int
-__sem_unlink(const char *name)
+_libc_sem_unlink_compat(const char *name)
{
return (ksem_unlink(name));
}
-int
-__sem_wait(sem_t *sem)
+static int
+enable_async_cancel(void)
{
+ int old;
- if (sem_check_validity(sem) != 0)
+ _pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
+ return (old);
+}
+
+static void
+restore_async_cancel(int val)
+{
+ _pthread_setcanceltype(val, NULL);
+}
+
+static int
+_umtx_wait_uint(volatile unsigned *mtx, unsigned id, const struct timespec *timeout)
+{
+ if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
+ timeout->tv_nsec <= 0))) {
+ errno = ETIMEDOUT;
return (-1);
+ }
+ return _umtx_op(__DEVOLATILE(void *, mtx),
+ UMTX_OP_WAIT_UINT_PRIVATE, id, NULL, __DECONST(void*, timeout));
+}
- return (ksem_wait((*sem)->semid));
+static int
+_umtx_wake(volatile void *mtx)
+{
+ return _umtx_op(__DEVOLATILE(void *, mtx), UMTX_OP_WAKE_PRIVATE,
+ 1, NULL, NULL);
+}
+
+#define TIMESPEC_SUB(dst, src, val) \
+ do { \
+ (dst)->tv_sec = (src)->tv_sec - (val)->tv_sec; \
+ (dst)->tv_nsec = (src)->tv_nsec - (val)->tv_nsec; \
+ if ((dst)->tv_nsec < 0) { \
+ (dst)->tv_sec--; \
+ (dst)->tv_nsec += 1000000000; \
+ } \
+ } while (0)
+
+
+static void
+sem_cancel_handler(void *arg)
+{
+ sem_t *sem = arg;
+
+ atomic_add_int(&(*sem)->nwaiters, -1);
+ if ((*sem)->nwaiters && (*sem)->count)
+ _umtx_wake(&(*sem)->count);
}
int
-__sem_trywait(sem_t *sem)
+_libc_sem_timedwait_compat(sem_t * __restrict sem,
+ const struct timespec * __restrict abstime)
{
- int retval;
+ struct timespec ts, ts2;
+ int val, retval, saved_cancel;
if (sem_check_validity(sem) != 0)
return (-1);
- if ((*sem)->syssem != 0)
- retval = ksem_trywait((*sem)->semid);
- else {
- _pthread_mutex_lock(&(*sem)->lock);
- if ((*sem)->count > 0) {
- (*sem)->count--;
- retval = 0;
- } else {
- errno = EAGAIN;
- retval = -1;
+ if ((*sem)->syssem != 0) {
+ saved_cancel = enable_async_cancel();
+ retval = ksem_wait((*sem)->semid);
+ restore_async_cancel(saved_cancel);
+ return (retval);
+ }
+
+ retval = 0;
+ _pthread_testcancel();
+ for (;;) {
+ while ((val = (*sem)->count) > 0) {
+ if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+ return (0);
+ }
+ if (retval)
+ break;
+ if (abstime) {
+ if (abstime->tv_nsec >= 1000000000 || abstime->tv_nsec < 0) {
+ errno = EINVAL;
+ return (-1);
+ }
+ clock_gettime(CLOCK_REALTIME, &ts);
+ TIMESPEC_SUB(&ts2, abstime, &ts);
}
- _pthread_mutex_unlock(&(*sem)->lock);
+ atomic_add_int(&(*sem)->nwaiters, 1);
+ pthread_cleanup_push(sem_cancel_handler, sem);
+ saved_cancel = enable_async_cancel();
+ retval = _umtx_wait_uint(&(*sem)->count, 0, abstime ? &ts2 : NULL);
+ restore_async_cancel(saved_cancel);
+ pthread_cleanup_pop(0);
+ atomic_add_int(&(*sem)->nwaiters, -1);
}
return (retval);
}
int
-__sem_timedwait(sem_t * __restrict sem,
- const struct timespec * __restrict abs_timeout)
+_libc_sem_wait_compat(sem_t *sem)
{
+ return _libc_sem_timedwait_compat(sem, NULL);
+}
+
+int
+_libc_sem_trywait_compat(sem_t *sem)
+{
+ int val;
+
if (sem_check_validity(sem) != 0)
return (-1);
- return (ksem_timedwait((*sem)->semid, abs_timeout));
+ if ((*sem)->syssem != 0)
+ return ksem_trywait((*sem)->semid);
+
+ while ((val = (*sem)->count) > 0) {
+ if (atomic_cmpset_acq_int(&(*sem)->count, val, val - 1))
+ return (0);
+ }
+ errno = EAGAIN;
+ return (-1);
}
int
-__sem_post(sem_t *sem)
+_libc_sem_post_compat(sem_t *sem)
{
if (sem_check_validity(sem) != 0)
return (-1);
- return (ksem_post((*sem)->semid));
+ if ((*sem)->syssem != 0)
+ return ksem_post((*sem)->semid);
+
+ atomic_add_rel_int(&(*sem)->count, 1);
+
+ if ((*sem)->nwaiters)
+ return _umtx_wake(&(*sem)->count);
+ return (0);
}
int
-__sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
+_libc_sem_getvalue_compat(sem_t * __restrict sem, int * __restrict sval)
{
int retval;
@@ -351,10 +470,7 @@ __sem_getvalue(sem_t * __restrict sem, i
if ((*sem)->syssem != 0)
retval = ksem_getvalue((*sem)->semid, sval);
else {
- _pthread_mutex_lock(&(*sem)->lock);
*sval = (int)(*sem)->count;
- _pthread_mutex_unlock(&(*sem)->lock);
-
retval = 0;
}
return (retval);
Added: head/lib/libc/gen/sem_new.c
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/lib/libc/gen/sem_new.c Tue Jan 5 02:37:59 2010 (r201546)
@@ -0,0 +1,470 @@
+/*
+ * Copyright (C) 2010 David Xu <davidxu at freebsd.org>.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice(s), this list of conditions and the following disclaimer as
+ * the first lines of this file unmodified other than the possible
+ * addition of one or more copyright notices.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice(s), this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
+ * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include "namespace.h"
+#include <sys/types.h>
+#include <sys/queue.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <machine/atomic.h>
+#include <sys/umtx.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <semaphore.h>
+#include <unistd.h>
+#include "un-namespace.h"
+
+__weak_reference(_libc_sem_close, sem_close);
+__weak_reference(_libc_sem_close, _sem_close);
+__weak_reference(_libc_sem_destroy, sem_destroy);
+__weak_reference(_libc_sem_destroy, _sem_destroy);
+__weak_reference(_libc_sem_getvalue, sem_getvalue);
+__weak_reference(_libc_sem_getvalue, _sem_getvalue);
+__weak_reference(_libc_sem_init, sem_init);
+__weak_reference(_libc_sem_init, _sem_init);
+__weak_reference(_libc_sem_open, sem_open);
+__weak_reference(_libc_sem_open, _sem_open);
+__weak_reference(_libc_sem_post, sem_post);
+__weak_reference(_libc_sem_post, _sem_post);
+__weak_reference(_libc_sem_timedwait, sem_timedwait);
+__weak_reference(_libc_sem_timedwait, _sem_timedwait);
+__weak_reference(_libc_sem_trywait, sem_trywait);
+__weak_reference(_libc_sem_trywait, _sem_trywait);
+__weak_reference(_libc_sem_unlink, sem_unlink);
+__weak_reference(_libc_sem_unlink, _sem_unlink);
+__weak_reference(_libc_sem_wait, sem_wait);
+__weak_reference(_libc_sem_wait, _sem_wait);
+
+#define SEM_PREFIX "/tmp/SEMD"
+#define SEM_MAGIC ((u_int32_t)0x73656d31)
+
+struct sem_nameinfo {
+ int open_count;
+ char *name;
+ sem_t *sem;
+ LIST_ENTRY(sem_nameinfo) next;
+};
+
+static pthread_once_t once = PTHREAD_ONCE_INIT;
+static pthread_mutex_t sem_llock;
+static LIST_HEAD(,sem_nameinfo) sem_list = LIST_HEAD_INITIALIZER(sem_list);
+
+static void
+sem_prefork()
+{
+
+ _pthread_mutex_lock(&sem_llock);
+}
+
+static void
+sem_postfork()
+{
+ _pthread_mutex_unlock(&sem_llock);
+}
+
+static void
+sem_child_postfork()
+{
+ _pthread_mutex_unlock(&sem_llock);
+}
+
+static void
+sem_module_init(void)
+{
+ pthread_mutexattr_t ma;
+
+ _pthread_mutexattr_init(&ma);
+ _pthread_mutexattr_settype(&ma, PTHREAD_MUTEX_RECURSIVE);
+ _pthread_mutex_init(&sem_llock, &ma);
+ _pthread_mutexattr_destroy(&ma);
+ _pthread_atfork(sem_prefork, sem_postfork, sem_child_postfork);
+}
+
+static inline int
+sem_check_validity(sem_t *sem)
+{
+
+ if (sem->_magic == SEM_MAGIC)
+ return (0);
+ else {
+ errno = EINVAL;
+ return (-1);
+ }
+}
+
+int
+_libc_sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+
+ if (value > SEM_VALUE_MAX) {
+ errno = EINVAL;
+ return (-1);
+ }
+
+ bzero(sem, sizeof(sem_t));
+ sem->_magic = SEM_MAGIC;
+ sem->_kern._count = (u_int32_t)value;
+ sem->_kern._has_waiters = 0;
+ sem->_kern._flags = pshared ? USYNC_PROCESS_SHARED : 0;
+ return (0);
+}
+
+sem_t *
+_libc_sem_open(const char *name, int flags, ...)
+{
+ char path[PATH_MAX];
+
+ struct stat sb;
+ va_list ap;
+ struct sem_nameinfo *ni = NULL;
+ sem_t *sem = NULL;
+ int fd = -1, mode, len;
+
+ if (name[0] != '/') {
+ errno = EINVAL;
+ return (NULL);
+ }
+ name++;
+
+ if (flags & ~(O_CREAT|O_EXCL)) {
+ errno = EINVAL;
+ return (NULL);
+ }
+
+ _pthread_once(&once, sem_module_init);
+
+ _pthread_mutex_lock(&sem_llock);
+ LIST_FOREACH(ni, &sem_list, next) {
+ if (strcmp(name, ni->name) == 0) {
+ ni->open_count++;
+ sem = ni->sem;
+ _pthread_mutex_unlock(&sem_llock);
+ return (sem);
+ }
+ }
+
+ if (flags & O_CREAT) {
+ va_start(ap, flags);
+ mode = va_arg(ap, int);
+ va_end(ap);
+ }
+
+ len = sizeof(*ni) + strlen(name) + 1;
+ ni = (struct sem_nameinfo *)malloc(len);
+ if (ni == NULL) {
+ errno = ENOSPC;
+ goto error;
+ }
+
+ ni->name = (char *)(ni+1);
+ strcpy(ni->name, name);
+
+ strcpy(path, SEM_PREFIX);
+ if (strlcat(path, name, sizeof(path)) >= sizeof(path)) {
+ errno = ENAMETOOLONG;
+ goto error;
+ }
+
+ fd = _open(path, flags|O_RDWR, mode);
+ if (fd == -1)
+ goto error;
+ if (flock(fd, LOCK_EX) == -1)
+ goto error;
+ if (_fstat(fd, &sb)) {
+ flock(fd, LOCK_UN);
+ goto error;
+ }
+ if (sb.st_size < sizeof(sem_t)) {
+ sem_t tmp;
+
+ tmp._magic = SEM_MAGIC;
+ tmp._kern._has_waiters = 0;
+ tmp._kern._count = 0;
+ tmp._kern._flags = USYNC_PROCESS_SHARED | SEM_NAMED;
+ if (_write(fd, &tmp, sizeof(tmp)) != sizeof(tmp)) {
+ flock(fd, LOCK_UN);
+ goto error;
+ }
+ }
+ flock(fd, LOCK_UN);
+ sem = (sem_t *)mmap(NULL, sizeof(sem_t), PROT_READ|PROT_WRITE,
+ MAP_SHARED|MAP_NOSYNC, fd, 0);
+ if (sem == MAP_FAILED) {
+ sem = NULL;
+ if (errno == ENOMEM)
+ errno = ENOSPC;
+ goto error;
+ }
+ if (sem->_magic != SEM_MAGIC) {
+ errno = EINVAL;
+ goto error;
+ }
+ ni->open_count = 1;
+ ni->sem = sem;
+ LIST_INSERT_HEAD(&sem_list, ni, next);
+ _pthread_mutex_unlock(&sem_llock);
+ _close(fd);
+ return (sem);
+
+error:
+ _pthread_mutex_unlock(&sem_llock);
+ if (fd != -1)
+ _close(fd);
+ if (sem != NULL)
+ munmap(sem, sizeof(sem_t));
+ free(ni);
+ return (SEM_FAILED);
+}
+
+int
+_libc_sem_close(sem_t *sem)
+{
+ struct sem_nameinfo *ni;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if (!(sem->_kern._flags & SEM_NAMED)) {
+ errno = EINVAL;
+ return (-1);
+ }
+
+ _pthread_mutex_lock(&sem_llock);
+ LIST_FOREACH(ni, &sem_list, next) {
+ if (sem == ni->sem) {
+ if (--ni->open_count > 0) {
+ _pthread_mutex_unlock(&sem_llock);
+ return (0);
+ }
+ else
+ break;
+ }
+ }
+
+ if (ni) {
+ LIST_REMOVE(ni, next);
+ _pthread_mutex_unlock(&sem_llock);
+ munmap(sem, sizeof(*sem));
+ free(ni);
+ return (0);
+ }
+ _pthread_mutex_unlock(&sem_llock);
+ return (-1);
+}
+
+int
+_libc_sem_unlink(const char *name)
+{
+ char path[PATH_MAX];
+
+ if (name[0] != '/') {
+ errno = ENOENT;
+ return -1;
+ }
+ name++;
+
+ strcpy(path, SEM_PREFIX);
+ if (strlcat(path, name, sizeof(path)) >= sizeof(path)) {
+ errno = ENAMETOOLONG;
+ return (-1);
+ }
+ return unlink(path);
+}
+
+int
+_libc_sem_destroy(sem_t *sem)
+{
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ if (sem->_kern._flags & SEM_NAMED) {
+ errno = EINVAL;
+ return (-1);
+ }
+ sem->_magic = 0;
+ return (0);
+}
+
+int
+_libc_sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
+{
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ *sval = (int)sem->_kern._count;
+ return (0);
+}
+
+static int
+usem_wake(struct _usem *sem)
+{
+ if (!sem->_has_waiters)
+ return (0);
+ return _umtx_op(sem, UMTX_OP_SEM_WAKE, 0, NULL, NULL);
+}
+
+static int
+usem_wait(struct _usem *sem, const struct timespec *timeout)
+{
+ if (timeout && (timeout->tv_sec < 0 || (timeout->tv_sec == 0 &&
+ timeout->tv_nsec <= 0))) {
+ errno = ETIMEDOUT;
+ return (-1);
+ }
+ return _umtx_op(sem, UMTX_OP_SEM_WAIT, 0, NULL,
+ __DECONST(void*, timeout));
+}
+
+int
+_libc_sem_trywait(sem_t *sem)
+{
+ int val;
+
+ if (sem_check_validity(sem) != 0)
+ return (-1);
+
+ while ((val = sem->_kern._count) > 0) {
+ if (atomic_cmpset_acq_int(&sem->_kern._count, val, val - 1))
+ return (0);
+ }
+ errno = EAGAIN;
+ return (-1);
+}
+
+static void
+sem_cancel_handler(void *arg)
+{
+ sem_t *sem = arg;
+
+ if (sem->_kern._has_waiters && sem->_kern._count)
+ usem_wake(&sem->_kern);
+}
+
+#define TIMESPEC_SUB(dst, src, val) \
+ do { \
+ (dst)->tv_sec = (src)->tv_sec - (val)->tv_sec; \
+ (dst)->tv_nsec = (src)->tv_nsec - (val)->tv_nsec; \
+ if ((dst)->tv_nsec < 0) { \
+ (dst)->tv_sec--; \
+ (dst)->tv_nsec += 1000000000; \
+ } \
+ } while (0)
+
+
+static int
+enable_async_cancel(void)
+{
+ int old;
+
+ _pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &old);
+ return (old);
+}
+
+static void
+restore_async_cancel(int val)
+{
+ _pthread_setcanceltype(val, NULL);
+}
+
+int
+_libc_sem_timedwait(sem_t * __restrict sem,
+ const struct timespec * __restrict abstime)
+{
+ struct timespec ts, ts2;
+ int val, retval, saved_cancel;
+
*** DIFF OUTPUT TRUNCATED AT 1000 LINES ***
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