add pthread_cancel, obtained from OpenBSD.

eischen (Daniel Eischen) added wrappers to protect against cancled
threads orphaning internal resources.

the cancelability code is still a bit fuzzy but works for test
programs of my own, OpenBSD's and some examples from ORA's books.

add readdir_r to both libc and libc_r

add some 'const' attributes to function parameters

Reviewed by: eischen, jasone

1 files changed, 7 insertions, 2 deletions

diff --git a/lib/libpthread/thread/thr_write.c b/lib/libpthread/thread/thr_write.c
index 9292add..09b09cd 100644
--- a/lib/libpthread/thread/thr_write.c
+++ b/lib/libpthread/thread/thr_write.c
@@ -50,9 +50,12 @@ write(int fd, const void *buf, size_t nbytes)
 	ssize_t num = 0;
 	ssize_t	ret;
 
+	_thread_enter_cancellation_point();
 	/* POSIX says to do just this: */
-	if (nbytes == 0)
+	if (nbytes == 0) {
+		_thread_leave_cancellation_point();
 		return (0);
+	}
 
 	/* Lock the file descriptor for write: */
 	if ((ret = _FD_LOCK(fd, FD_WRITE, NULL)) == 0) {
@@ -64,7 +67,8 @@ write(int fd, const void *buf, size_t nbytes)
 			/* File is not open for write: */
 			errno = EBADF;
 			_FD_UNLOCK(fd, FD_WRITE);
-			return (-1);
+		_thread_leave_cancellation_point();
+		return (-1);
 		}
 
 		/* Check if file operations are to block */
@@ -129,6 +133,7 @@ write(int fd, const void *buf, size_t nbytes)
 		}
 		_FD_UNLOCK(fd, FD_RDWR);
 	}
+	_thread_leave_cancellation_point();
 	return (ret);
 }
 #endif