Add signal handler wrapper, the reason to add it becauses there are

some cases we want to improve:
  1) if a thread signal got a signal while in cancellation point,
     it is possible the TDP_WAKEUP may be eaten by signal handler
     if the handler called some interruptibly system calls.
  2) In signal handler, we want to disable cancellation.
  3) When thread holding some low level locks, it is better to
     disable signal, those code need not to worry reentrancy,
     sigprocmask system call is avoided because it is a bit expensive.
The signal handler wrapper works in this way:
  1) libthr installs its signal handler if user code invokes sigaction
     to install its handler, the user handler is recorded in internal
     array.
  2) when a signal is delivered, libthr's signal handler is invoke,
     libthr checks if thread holds some low level lock or is in critical
     region, if it is true, the signal is buffered, and all signals are
     masked, once the thread leaves critical region, correct signal
     mask is restored and buffered signal is processed.
  3) before user signal handler is invoked, cancellation is temporarily
     disabled, after user signal handler is returned, cancellation state
     is restored, and pending cancellation is rescheduled.

1 files changed, 57 insertions, 72 deletions

diff --git a/lib/libthr/thread/thr_syscalls.c b/lib/libthr/thread/thr_syscalls.c
index 73fa56f..2327d74 100644
--- a/lib/libthr/thread/thr_syscalls.c
+++ b/lib/libthr/thread/thr_syscalls.c
@@ -169,9 +169,9 @@ __accept(int s, struct sockaddr *addr, socklen_t *addrlen)
 	int ret;
 
 	curthread = _get_curthread();
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_accept(s, addr, addrlen);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
  	return (ret);
 }
@@ -187,7 +187,7 @@ __aio_suspend(const struct aiocb * const iocbs[], int niocb, const struct
 
 	_thr_cancel_enter(curthread);
 	ret = __sys_aio_suspend(iocbs, niocb, timeout);
-	_thr_cancel_leave(curthread);
+	_thr_cancel_leave(curthread, 1);
 
 	return (ret);
 }
@@ -207,9 +207,9 @@ __close(int fd)
 	struct pthread	*curthread = _get_curthread();
 	int	ret;
 
-	_thr_cancel_enter_defer(curthread, 0);
+	_thr_cancel_enter2(curthread, 0);
 	ret = __sys_close(fd);
-	_thr_cancel_leave_defer(curthread, 1);
+	_thr_cancel_leave(curthread, 1);
 	
 	return (ret);
 }
@@ -226,9 +226,9 @@ __connect(int fd, const struct sockaddr *name, socklen_t namelen)
 	struct pthread *curthread = _get_curthread();
 	int ret;
 
-	_thr_cancel_enter_defer(curthread, 0);
+	_thr_cancel_enter(curthread);
 	ret = __sys_connect(fd, name, namelen);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
  	return (ret);
 }
@@ -245,9 +245,9 @@ ___creat(const char *path, mode_t mode)
 	struct pthread *curthread = _get_curthread();
 	int ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __creat(path, mode);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 	
 	return ret;
 }
@@ -269,30 +269,15 @@ __fcntl(int fd, int cmd,...)
 	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:
-	case F_SETFL:
-		ret = __sys_fcntl(fd, cmd, va_arg(ap, int));
-		break;
-	case F_GETFD:
-	case F_GETFL:
-		ret = __sys_fcntl(fd, cmd);
-		break;
-	case F_OSETLKW:
-	case F_SETLKW:
-		_thr_cancel_enter_defer(curthread, 1);
+	if (cmd == F_OSETLKW || cmd == F_SETLKW) {
+		_thr_cancel_enter(curthread);
 #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_defer(curthread, ret == -1);
-		break;
-	default:
+		_thr_cancel_leave(curthread, ret == -1);
+	} else {
 #ifdef SYSCALL_COMPAT
 		ret = __fcntl_compat(fd, cmd, va_arg(ap, void *));
 #else
@@ -316,9 +301,9 @@ __fsync(int fd)
 	struct pthread *curthread = _get_curthread();
 	int	ret;
 
-	_thr_cancel_enter_defer(curthread, 0);
+	_thr_cancel_enter2(curthread, 0);
 	ret = __sys_fsync(fd);
-	_thr_cancel_leave_defer(curthread, 1);
+	_thr_cancel_leave(curthread, 1);
 
 	return (ret);
 }
@@ -335,9 +320,9 @@ __msync(void *addr, size_t len, int flags)
 	struct pthread *curthread = _get_curthread();
 	int	ret;
 
-	_thr_cancel_enter_defer(curthread, 0);
+	_thr_cancel_enter2(curthread, 0);
 	ret = __sys_msync(addr, len, flags);
-	_thr_cancel_leave_defer(curthread, 1);
+	_thr_cancel_leave(curthread, 1);
 
 	return ret;
 }
@@ -353,7 +338,7 @@ __nanosleep(const struct timespec *time_to_sleep,
 
 	_thr_cancel_enter(curthread);
 	ret = __sys_nanosleep(time_to_sleep, time_remaining);
-	_thr_cancel_leave(curthread);
+	_thr_cancel_leave(curthread, 1);
 
 	return (ret);
 }
@@ -380,9 +365,9 @@ __open(const char *path, int flags,...)
 		va_end(ap);
 	}
 	
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_open(path, flags, mode);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
 	return ret;
 }
@@ -410,9 +395,9 @@ __openat(int fd, const char *path, int flags, ...)
 		va_end(ap);
 	}
 	
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_openat(fd, path, flags, mode);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
 	return ret;
 }
@@ -430,9 +415,9 @@ __poll(struct pollfd *fds, unsigned int nfds, int timeout)
 	struct pthread *curthread = _get_curthread();
 	int ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_poll(fds, nfds, timeout);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
 	return ret;
 }
@@ -451,9 +436,9 @@ ___pselect(int count, fd_set *rfds, fd_set *wfds, fd_set *efds,
 	struct pthread *curthread = _get_curthread();
 	int ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_pselect(count, rfds, wfds, efds, timo, mask);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
 	return (ret);
 }
@@ -471,9 +456,9 @@ __read(int fd, void *buf, size_t nbytes)
 	struct pthread *curthread = _get_curthread();
 	ssize_t	ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_read(fd, buf, nbytes);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 
 	return ret;
 }
@@ -491,9 +476,9 @@ __readv(int fd, const struct iovec *iov, int iovcnt)
 	struct pthread *curthread = _get_curthread();
 	ssize_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_readv(fd, iov, iovcnt);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 	return ret;
 }
 
@@ -511,9 +496,9 @@ __recvfrom(int s, void *b, size_t l, int f, struct sockaddr *from,
 	struct pthread *curthread = _get_curthread();
 	ssize_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_recvfrom(s, b, l, f, from, fl);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 	return (ret);
 }
 
@@ -530,9 +515,9 @@ __recvmsg(int s, struct msghdr *m, int f)
 	struct pthread *curthread = _get_curthread();
 	ssize_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_recvmsg(s, m, f);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 	return (ret);
 }
 
@@ -550,9 +535,9 @@ __select(int numfds, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
 	struct pthread *curthread = _get_curthread();
 	int ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_select(numfds, readfds, writefds, exceptfds, timeout);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 	return ret;
 }
 
@@ -569,9 +554,9 @@ __sendmsg(int s, const struct msghdr *m, int f)
 	struct pthread *curthread = _get_curthread();
 	ssize_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_sendmsg(s, m, f);
-	_thr_cancel_leave_defer(curthread, ret <= 0);
+	_thr_cancel_leave(curthread, ret <= 0);
 	return (ret);
 }
 
@@ -589,9 +574,9 @@ __sendto(int s, const void *m, size_t l, int f, const struct sockaddr *t,
 	struct pthread *curthread = _get_curthread();
 	ssize_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_sendto(s, m, l, f, t, tl);
-	_thr_cancel_leave_defer(curthread, ret <= 0);
+	_thr_cancel_leave(curthread, ret <= 0);
 	return (ret);
 }
 
@@ -605,7 +590,7 @@ ___sleep(unsigned int seconds)
 
 	_thr_cancel_enter(curthread);
 	ret = __sleep(seconds);
-	_thr_cancel_leave(curthread);
+	_thr_cancel_leave(curthread, 1);
 	
 	return (ret);
 }
@@ -620,7 +605,7 @@ ___system(const char *string)
 
 	_thr_cancel_enter(curthread);
 	ret = __system(string);
-	_thr_cancel_leave(curthread);
+	_thr_cancel_leave(curthread, 1);
 	
 	return ret;
 }
@@ -638,9 +623,9 @@ ___tcdrain(int fd)
 	struct pthread *curthread = _get_curthread();
 	int	ret;
 	
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __tcdrain(fd);
-	_thr_cancel_leave_defer(curthread, ret == -1);
+	_thr_cancel_leave(curthread, ret == -1);
 	return (ret);
 }
 
@@ -654,7 +639,7 @@ ___usleep(useconds_t useconds)
 
 	_thr_cancel_enter(curthread);
 	ret = __usleep(useconds);
-	_thr_cancel_leave(curthread);
+	_thr_cancel_leave(curthread, 1);
 	
 	return (ret);
 }
@@ -672,9 +657,9 @@ ___wait(int *istat)
 	struct pthread *curthread = _get_curthread();
 	pid_t	ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __wait(istat);
-	_thr_cancel_leave_defer(curthread, ret <= 0);
+	_thr_cancel_leave(curthread, ret <= 0);
 
 	return ret;
 }
@@ -692,9 +677,9 @@ __wait3(int *status, int options, struct rusage *rusage)
 	struct pthread *curthread = _get_curthread();
 	pid_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = _wait4(WAIT_ANY, status, options, rusage);
-	_thr_cancel_leave_defer(curthread, ret <= 0);
+	_thr_cancel_leave(curthread, ret <= 0);
 
 	return (ret);
 }
@@ -712,9 +697,9 @@ __wait4(pid_t pid, int *status, int options, struct rusage *rusage)
 	struct pthread *curthread = _get_curthread();
 	pid_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_wait4(pid, status, options, rusage);
-	_thr_cancel_leave_defer(curthread, ret <= 0);
+	_thr_cancel_leave(curthread, ret <= 0);
 
 	return ret;
 }
@@ -732,9 +717,9 @@ ___waitpid(pid_t wpid, int *status, int options)
 	struct pthread *curthread = _get_curthread();
 	pid_t	ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __waitpid(wpid, status, options);
-	_thr_cancel_leave_defer(curthread, ret <= 0);
+	_thr_cancel_leave(curthread, ret <= 0);
 	
 	return ret;
 }
@@ -752,9 +737,9 @@ __write(int fd, const void *buf, size_t nbytes)
 	struct pthread *curthread = _get_curthread();
 	ssize_t	ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_write(fd, buf, nbytes);
-	_thr_cancel_leave_defer(curthread, (ret <= 0));
+	_thr_cancel_leave(curthread, (ret <= 0));
 	return ret;
 }
 
@@ -771,8 +756,8 @@ __writev(int fd, const struct iovec *iov, int iovcnt)
 	struct pthread *curthread = _get_curthread();
 	ssize_t ret;
 
-	_thr_cancel_enter_defer(curthread, 1);
+	_thr_cancel_enter(curthread);
 	ret = __sys_writev(fd, iov, iovcnt);
-	_thr_cancel_leave_defer(curthread, (ret <= 0));
+	_thr_cancel_leave(curthread, (ret <= 0));
 	return ret;
 }