svn commit: r211524 - head/lib/libthr/thread
David Xu
davidxu at FreeBSD.org
Fri Aug 20 05:15:40 UTC 2010
Author: davidxu
Date: Fri Aug 20 05:15:39 2010
New Revision: 211524
URL: http://svn.freebsd.org/changeset/base/211524
Log:
In current implementation, thread cancellation is done in signal handler,
which does not know what is the state of interrupted system call, for
example, open() system call opened a file and the thread is still cancelled,
result is descriptor leak, there are other problems which can cause resource
leak or undeterminable side effect when a thread is cancelled. However, this
is no longer true in new implementation.
In defering mode, a thread is canceled if cancellation request is pending and
later the thread enters a cancellation point, otherwise, a later
pthread_cancel() just causes SIGCANCEL to be sent to the target thread, and
causes target thread to abort system call, userland code in libthr then checks
cancellation state, and cancels the thread if needed. For example, the
cancellation point open(), the thread may be canceled at start,
but later, if it opened a file descriptor, it is not canceled, this avoids
file handle leak. Another example is read(), a thread may be canceled at start
of the function, but later, if it read some bytes from a socket, the thread
is not canceled, the caller then can decide if it should still enable cancelling
or disable it and continue reading data until it thinks it has read all
bytes of a packet, and keeps a protocol stream in health state, if user ignores
partly reading of a packet without disabling cancellation, then second iteration
of read loop cause the thread to be cancelled.
An exception is that the close() cancellation point always closes a file handle
despite whether the thread is cancelled or not.
The old mechanism is still kept, for a functions which is not so easily to
fix a cancellation problem, the rough mechanism is used.
Reviewed by: kib@
Modified:
head/lib/libthr/thread/thr_cancel.c
head/lib/libthr/thread/thr_cond.c
head/lib/libthr/thread/thr_join.c
head/lib/libthr/thread/thr_private.h
head/lib/libthr/thread/thr_sig.c
head/lib/libthr/thread/thr_syscalls.c
Modified: head/lib/libthr/thread/thr_cancel.c
==============================================================================
--- head/lib/libthr/thread/thr_cancel.c Fri Aug 20 04:28:30 2010 (r211523)
+++ head/lib/libthr/thread/thr_cancel.c Fri Aug 20 05:15:39 2010 (r211524)
@@ -42,7 +42,7 @@ static inline void
testcancel(struct pthread *curthread)
{
if (__predict_false(SHOULD_CANCEL(curthread) &&
- !THR_IN_CRITICAL(curthread) && curthread->cancel_defer == 0))
+ !THR_IN_CRITICAL(curthread)))
_pthread_exit(PTHREAD_CANCELED);
}
@@ -143,40 +143,44 @@ _pthread_testcancel(void)
void
_thr_cancel_enter(struct pthread *curthread)
{
- if (curthread->cancel_enable) {
- curthread->cancel_point++;
+ curthread->cancel_point++;
+ if (curthread->cancel_enable)
testcancel(curthread);
+}
+
+void
+_thr_cancel_enter_defer(struct pthread *curthread, int maycancel)
+{
+ curthread->cancel_defer++;
+ curthread->cancel_point++;
+ if (__predict_false(SHOULD_CANCEL(curthread) &&
+ !THR_IN_CRITICAL(curthread))) {
+ if (!maycancel)
+ thr_wake(curthread->tid);
+ else
+ _pthread_exit(PTHREAD_CANCELED);
}
}
void
_thr_cancel_leave(struct pthread *curthread)
{
- if (curthread->cancel_enable)
- curthread->cancel_point--;
+ curthread->cancel_point--;
}
void
-_thr_cancel_enter_defer(struct pthread *curthread)
+_thr_cancel_leave2(struct pthread *curthread, int maycancel)
{
- if (curthread->cancel_enable) {
- curthread->cancel_point++;
+ if (curthread->cancel_enable && maycancel)
testcancel(curthread);
- curthread->cancel_defer++;
- }
+ curthread->cancel_point--;
}
void
-_thr_cancel_leave_defer(struct pthread *curthread, int check)
+_thr_cancel_leave_defer(struct pthread *curthread, int maycancel)
{
- if (curthread->cancel_enable) {
- if (!check) {
- curthread->cancel_point--;
- curthread->cancel_defer--;
- } else {
- curthread->cancel_defer--;
- testcancel(curthread);
- curthread->cancel_point--;
- }
- }
+ if (curthread->cancel_enable && maycancel)
+ testcancel(curthread);
+ curthread->cancel_point--;
+ curthread->cancel_defer--;
}
Modified: head/lib/libthr/thread/thr_cond.c
==============================================================================
--- head/lib/libthr/thread/thr_cond.c Fri Aug 20 04:28:30 2010 (r211523)
+++ head/lib/libthr/thread/thr_cond.c Fri Aug 20 05:15:39 2010 (r211524)
@@ -162,6 +162,14 @@ cond_cancel_handler(void *arg)
_mutex_cv_lock(info->mutex, info->count);
}
+/*
+ * Cancellation behaivor:
+ * Thread may be canceled at start, if thread is canceled, it means it
+ * did not get a wakeup from pthread_cond_signal(), otherwise, it is
+ * not canceled.
+ * Thread cancellation never cause wakeup from pthread_cond_signal()
+ * to be lost.
+ */
static int
cond_wait_common(pthread_cond_t *cond, pthread_mutex_t *mutex,
const struct timespec *abstime, int cancel)
@@ -180,6 +188,8 @@ cond_wait_common(pthread_cond_t *cond, p
(ret = init_static(curthread, cond)) != 0))
return (ret);
+ _thr_testcancel(curthread);
+
cv = *cond;
THR_UMUTEX_LOCK(curthread, &cv->c_lock);
ret = _mutex_cv_unlock(mutex, &info.count);
@@ -200,10 +210,10 @@ cond_wait_common(pthread_cond_t *cond, p
if (cancel) {
THR_CLEANUP_PUSH(curthread, cond_cancel_handler, &info);
- _thr_cancel_enter_defer(curthread);
+ _thr_cancel_enter_defer(curthread, 0);
ret = _thr_ucond_wait(&cv->c_kerncv, &cv->c_lock, tsp, 1);
info.cond = NULL;
- _thr_cancel_leave_defer(curthread, ret);
+ _thr_cancel_leave_defer(curthread, (ret != 0));
THR_CLEANUP_POP(curthread, 0);
} else {
ret = _thr_ucond_wait(&cv->c_kerncv, &cv->c_lock, tsp, 0);
Modified: head/lib/libthr/thread/thr_join.c
==============================================================================
--- head/lib/libthr/thread/thr_join.c Fri Aug 20 04:28:30 2010 (r211523)
+++ head/lib/libthr/thread/thr_join.c Fri Aug 20 05:15:39 2010 (r211524)
@@ -68,6 +68,10 @@ _pthread_timedjoin_np(pthread_t pthread,
return (join_common(pthread, thread_return, abstime));
}
+/*
+ * Cancellation behavior:
+ * if the thread is canceled, joinee is not recycled.
+ */
static int
join_common(pthread_t pthread, void **thread_return,
const struct timespec *abstime)
@@ -103,10 +107,11 @@ join_common(pthread_t pthread, void **th
THREAD_LIST_UNLOCK(curthread);
THR_CLEANUP_PUSH(curthread, backout_join, pthread);
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
tid = pthread->tid;
while (pthread->tid != TID_TERMINATED) {
+ _thr_testcancel(curthread);
if (abstime != NULL) {
clock_gettime(CLOCK_REALTIME, &ts);
TIMESPEC_SUB(&ts2, abstime, &ts);
@@ -122,7 +127,7 @@ join_common(pthread_t pthread, void **th
break;
}
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, 0);
THR_CLEANUP_POP(curthread, 0);
if (ret == ETIMEDOUT) {
Modified: head/lib/libthr/thread/thr_private.h
==============================================================================
--- head/lib/libthr/thread/thr_private.h Fri Aug 20 04:28:30 2010 (r211523)
+++ head/lib/libthr/thread/thr_private.h Fri Aug 20 05:15:39 2010 (r211524)
@@ -644,7 +644,8 @@ void _thread_printf(int, const char *, .
void _thr_spinlock_init(void) __hidden;
void _thr_cancel_enter(struct pthread *) __hidden;
void _thr_cancel_leave(struct pthread *) __hidden;
-void _thr_cancel_enter_defer(struct pthread *) __hidden;
+void _thr_cancel_leave2(struct pthread *, int) __hidden;
+void _thr_cancel_enter_defer(struct pthread *, int) __hidden;
void _thr_cancel_leave_defer(struct pthread *, int) __hidden;
void _thr_testcancel(struct pthread *) __hidden;
void _thr_signal_block(struct pthread *) __hidden;
Modified: head/lib/libthr/thread/thr_sig.c
==============================================================================
--- head/lib/libthr/thread/thr_sig.c Fri Aug 20 04:28:30 2010 (r211523)
+++ head/lib/libthr/thread/thr_sig.c Fri Aug 20 05:15:39 2010 (r211524)
@@ -67,8 +67,6 @@ sigcancel_handler(int sig __unused,
{
struct pthread *curthread = _get_curthread();
- if (curthread->cancel_defer && curthread->cancel_pending)
- thr_wake(curthread->tid);
curthread->in_sigcancel_handler++;
_thr_ast(curthread);
curthread->in_sigcancel_handler--;
@@ -77,13 +75,50 @@ sigcancel_handler(int sig __unused,
void
_thr_ast(struct pthread *curthread)
{
- if (!THR_IN_CRITICAL(curthread)) {
- _thr_testcancel(curthread);
- if (__predict_false((curthread->flags &
- (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED))
- == THR_FLAGS_NEED_SUSPEND))
- _thr_suspend_check(curthread);
+
+ if (THR_IN_CRITICAL(curthread))
+ return;
+
+ if (curthread->cancel_pending && curthread->cancel_enable
+ && !curthread->cancelling) {
+ if (curthread->cancel_async) {
+ /*
+ * asynchronous cancellation mode, act upon
+ * immediately.
+ */
+ _pthread_exit(PTHREAD_CANCELED);
+ } else {
+ /*
+ * Otherwise, we are in defer mode, and we are at
+ * cancel point, tell kernel to not block the current
+ * thread on next cancelable system call.
+ *
+ * There are two cases we should call thr_wake() to
+ * turn on TDP_WAKEUP in kernel:
+ * 1) we are going to call a cancelable system call,
+ * non-zero cancel_point means we are already in
+ * cancelable state, next system call is cancelable.
+ * 2) because _thr_ast() may be called by
+ * THR_CRITICAL_LEAVE() which is used by rtld rwlock
+ * and any libthr internal locks, when rtld rwlock
+ * is used, it is mostly caused my an unresolved PLT.
+ * those routines may clear the TDP_WAKEUP flag by
+ * invoking some system calls, in those cases, we
+ * also should reenable the flag.
+ */
+ if (curthread->cancel_point) {
+ if (curthread->cancel_defer)
+ thr_wake(curthread->tid);
+ else
+ _pthread_exit(PTHREAD_CANCELED);
+ }
+ }
}
+
+ if (__predict_false((curthread->flags &
+ (THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED))
+ == THR_FLAGS_NEED_SUSPEND))
+ _thr_suspend_check(curthread);
}
void
@@ -296,6 +331,11 @@ _sigtimedwait(const sigset_t *set, sigin
return (ret);
}
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, if thread got signal,
+ * it is not canceled.
+ */
int
__sigtimedwait(const sigset_t *set, siginfo_t *info,
const struct timespec * timeout)
@@ -311,9 +351,9 @@ __sigtimedwait(const sigset_t *set, sigi
pset = &newset;
} else
pset = set;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_sigtimedwait(pset, info, timeout);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, (ret == -1));
return (ret);
}
@@ -335,6 +375,11 @@ _sigwaitinfo(const sigset_t *set, siginf
return (ret);
}
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, if thread got signal,
+ * it is not canceled.
+ */
int
__sigwaitinfo(const sigset_t *set, siginfo_t *info)
{
@@ -350,9 +395,9 @@ __sigwaitinfo(const sigset_t *set, sigin
} else
pset = set;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_sigwaitinfo(pset, info);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
@@ -374,6 +419,11 @@ _sigwait(const sigset_t *set, int *sig)
return (ret);
}
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, if thread got signal,
+ * it is not canceled.
+ */
int
__sigwait(const sigset_t *set, int *sig)
{
@@ -389,8 +439,8 @@ __sigwait(const sigset_t *set, int *sig)
} else
pset = set;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_sigwait(pset, sig);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, (ret != 0));
return (ret);
}
Modified: head/lib/libthr/thread/thr_syscalls.c
==============================================================================
--- head/lib/libthr/thread/thr_syscalls.c Fri Aug 20 04:28:30 2010 (r211523)
+++ head/lib/libthr/thread/thr_syscalls.c Fri Aug 20 05:15:39 2010 (r211524)
@@ -158,6 +158,10 @@ ssize_t __writev(int, const struct iovec
__weak_reference(__accept, accept);
+/*
+ * Cancellation behavior:
+ * If thread is canceled, no socket is created.
+ */
int
__accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
@@ -165,9 +169,9 @@ __accept(int s, struct sockaddr *addr, s
int ret;
curthread = _get_curthread();
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_accept(s, addr, addrlen);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
@@ -190,61 +194,84 @@ __aio_suspend(const struct aiocb * const
__weak_reference(__close, close);
+/*
+ * Cancellation behavior:
+ * According to manual of close(), the file descriptor is always deleted.
+ * Here, thread is only canceled after the system call, so the file
+ * descriptor is always deleted despite whether the thread is canceled
+ * or not.
+ */
int
__close(int fd)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 0);
ret = __sys_close(fd);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, 1);
return (ret);
}
__weak_reference(__connect, connect);
+/*
+ * Cancellation behavior:
+ * If the thread is canceled, connection is not made.
+ */
int
__connect(int fd, const struct sockaddr *name, socklen_t namelen)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 0);
ret = __sys_connect(fd, name, namelen);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
__weak_reference(___creat, creat);
+/*
+ * Cancellation behavior:
+ * If thread is canceled, file is not created.
+ */
int
___creat(const char *path, mode_t mode)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __creat(path, mode);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(__fcntl, fcntl);
+/*
+ * Cancellation behavior:
+ * According to specification, only F_SETLKW is a cancellation point.
+ * Thread is only canceled at start, or canceled if the system call
+ * is failure, this means the function does not generate side effect
+ * if it is canceled.
+ */
int
__fcntl(int fd, int cmd,...)
{
struct pthread *curthread = _get_curthread();
int ret;
va_list ap;
-
+
va_start(ap, cmd);
switch (cmd) {
case F_DUPFD:
+ case F_DUP2FD:
ret = __sys_fcntl(fd, cmd, va_arg(ap, int));
break;
case F_SETFD:
@@ -255,16 +282,15 @@ __fcntl(int fd, int cmd,...)
case F_GETFL:
ret = __sys_fcntl(fd, cmd);
break;
-
case F_OSETLKW:
case F_SETLKW:
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
#ifdef SYSCALL_COMPAT
ret = __fcntl_compat(fd, cmd, va_arg(ap, void *));
#else
ret = __sys_fcntl(fd, cmd, va_arg(ap, void *));
#endif
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
break;
default:
#ifdef SYSCALL_COMPAT
@@ -280,30 +306,38 @@ __fcntl(int fd, int cmd,...)
__weak_reference(__fsync, fsync);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled after system call.
+ */
int
__fsync(int fd)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 0);
ret = __sys_fsync(fd);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, 1);
return (ret);
}
__weak_reference(__msync, msync);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled after system call.
+ */
int
__msync(void *addr, size_t len, int flags)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 0);
ret = __sys_msync(addr, len, flags);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, 1);
return ret;
}
@@ -326,6 +360,10 @@ __nanosleep(const struct timespec *time_
__weak_reference(__open, open);
+/*
+ * Cancellation behavior:
+ * If the thread is canceled, file is not opened.
+ */
int
__open(const char *path, int flags,...)
{
@@ -334,8 +372,6 @@ __open(const char *path, int flags,...)
int mode = 0;
va_list ap;
- _thr_cancel_enter(curthread);
-
/* Check if the file is being created: */
if (flags & O_CREAT) {
/* Get the creation mode: */
@@ -344,15 +380,19 @@ __open(const char *path, int flags,...)
va_end(ap);
}
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_open(path, flags, mode);
-
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(__openat, openat);
+/*
+ * Cancellation behavior:
+ * If the thread is canceled, file is not opened.
+ */
int
__openat(int fd, const char *path, int flags, ...)
{
@@ -361,7 +401,6 @@ __openat(int fd, const char *path, int f
int mode = 0;
va_list ap;
- _thr_cancel_enter(curthread);
/* Check if the file is being created: */
if (flags & O_CREAT) {
@@ -371,30 +410,40 @@ __openat(int fd, const char *path, int f
va_end(ap);
}
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_openat(fd, path, flags, mode);
-
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(__poll, poll);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns something,
+ * the thread is not canceled.
+ */
int
__poll(struct pollfd *fds, unsigned int nfds, int timeout)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_poll(fds, nfds, timeout);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(___pselect, pselect);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns something,
+ * the thread is not canceled.
+ */
int
___pselect(int count, fd_set *rfds, fd_set *wfds, fd_set *efds,
const struct timespec *timo, const sigset_t *mask)
@@ -402,45 +451,59 @@ ___pselect(int count, fd_set *rfds, fd_s
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_pselect(count, rfds, wfds, efds, timo, mask);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
__weak_reference(__read, read);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call got some data,
+ * the thread is not canceled.
+ */
ssize_t
__read(int fd, void *buf, size_t nbytes)
{
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_read(fd, buf, nbytes);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(__readv, readv);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call got some data,
+ * the thread is not canceled.
+ */
ssize_t
__readv(int fd, const struct iovec *iov, int iovcnt)
{
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_readv(fd, iov, iovcnt);
- _thr_cancel_leave(curthread);
-
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(__recvfrom, recvfrom);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call got some data,
+ * the thread is not canceled.
+ */
ssize_t
__recvfrom(int s, void *b, size_t l, int f, struct sockaddr *from,
socklen_t *fl)
@@ -448,28 +511,38 @@ __recvfrom(int s, void *b, size_t l, int
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_recvfrom(s, b, l, f, from, fl);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
__weak_reference(__recvmsg, recvmsg);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call got some data,
+ * the thread is not canceled.
+ */
ssize_t
__recvmsg(int s, struct msghdr *m, int f)
{
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_recvmsg(s, m, f);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
__weak_reference(__select, select);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns something,
+ * the thread is not canceled.
+ */
int
__select(int numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
struct timeval *timeout)
@@ -477,28 +550,38 @@ __select(int numfds, fd_set *readfds, fd
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_select(numfds, readfds, writefds, exceptfds, timeout);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret == -1);
return ret;
}
__weak_reference(__sendmsg, sendmsg);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call sent
+ * data, the thread is not canceled.
+ */
ssize_t
__sendmsg(int s, const struct msghdr *m, int f)
{
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_sendmsg(s, m, f);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret <= 0);
return (ret);
}
__weak_reference(__sendto, sendto);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call sent some
+ * data, the thread is not canceled.
+ */
ssize_t
__sendto(int s, const void *m, size_t l, int f, const struct sockaddr *t,
socklen_t tl)
@@ -506,9 +589,9 @@ __sendto(int s, const void *m, size_t l,
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_sendto(s, m, l, f, t, tl);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret <= 0);
return (ret);
}
@@ -544,16 +627,20 @@ ___system(const char *string)
__weak_reference(___tcdrain, tcdrain);
+/*
+ * Cancellation behavior:
+ * If thread is canceled, the system call is not completed,
+ * this means not all bytes were drained.
+ */
int
___tcdrain(int fd)
{
struct pthread *curthread = _get_curthread();
int ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __tcdrain(fd);
- _thr_cancel_leave(curthread);
-
+ _thr_cancel_leave_defer(curthread, ret == -1);
return (ret);
}
@@ -574,90 +661,118 @@ ___usleep(useconds_t useconds)
__weak_reference(___wait, wait);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns
+ * a child pid, the thread is not canceled.
+ */
pid_t
___wait(int *istat)
{
struct pthread *curthread = _get_curthread();
pid_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __wait(istat);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret <= 0);
return ret;
}
__weak_reference(__wait3, wait3);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns
+ * a child pid, the thread is not canceled.
+ */
pid_t
__wait3(int *status, int options, struct rusage *rusage)
{
struct pthread *curthread = _get_curthread();
pid_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = _wait4(WAIT_ANY, status, options, rusage);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret <= 0);
return (ret);
}
__weak_reference(__wait4, wait4);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns
+ * a child pid, the thread is not canceled.
+ */
pid_t
__wait4(pid_t pid, int *status, int options, struct rusage *rusage)
{
struct pthread *curthread = _get_curthread();
pid_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_wait4(pid, status, options, rusage);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret <= 0);
return ret;
}
__weak_reference(___waitpid, waitpid);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the system call returns
+ * a child pid, the thread is not canceled.
+ */
pid_t
___waitpid(pid_t wpid, int *status, int options)
{
struct pthread *curthread = _get_curthread();
pid_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __waitpid(wpid, status, options);
- _thr_cancel_leave(curthread);
+ _thr_cancel_leave_defer(curthread, ret <= 0);
return ret;
}
__weak_reference(__write, write);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the thread wrote some data,
+ * it is not canceled.
+ */
ssize_t
__write(int fd, const void *buf, size_t nbytes)
{
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_write(fd, buf, nbytes);
- _thr_cancel_leave(curthread);
-
+ _thr_cancel_leave_defer(curthread, (ret <= 0));
return ret;
}
__weak_reference(__writev, writev);
+/*
+ * Cancellation behavior:
+ * Thread may be canceled at start, but if the thread wrote some data,
+ * it is not canceled.
+ */
ssize_t
__writev(int fd, const struct iovec *iov, int iovcnt)
{
struct pthread *curthread = _get_curthread();
ssize_t ret;
- _thr_cancel_enter(curthread);
+ _thr_cancel_enter_defer(curthread, 1);
ret = __sys_writev(fd, iov, iovcnt);
- _thr_cancel_leave(curthread);
-
+ _thr_cancel_leave_defer(curthread, (ret <= 0));
return ret;
}
More information about the svn-src-head
mailing list