Date: Fri, 20 Aug 2010 05:15:39 +0000 (UTC) From: David Xu <davidxu@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r211524 - head/lib/libthr/thread Message-ID: <201008200515.o7K5Fdsq027054@svn.freebsd.org>
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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; }
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