MFC r315526

Add clock_nanosleep()

Add a clock_nanosleep() syscall, as specified by POSIX.
Make nanosleep() a wrapper around it.

Attach the clock_nanosleep test from NetBSD. Adjust it for the
FreeBSD behavior of updating rmtp only when interrupted by a signal.
I believe this to be POSIX-compliant, since POSIX mentions the rmtp
parameter only in the paragraph about EINTR. This is also what
Linux does. (NetBSD updates rmtp unconditionally.)

Copy the whole nanosleep.2 man page from NetBSD because it is complete
and closely resembles the POSIX description. Edit, polish, and reword it
a bit, being sure to keep any relevant text from the FreeBSD page.

Regenerate syscall files.

Relnotes:	yes
Sponsored by:	Dell EMC

2 files changed, 19 insertions, 0 deletions

diff --git a/lib/libthr/thread/thr_private.h b/lib/libthr/thread/thr_private.h
index 9bea65f..56ecdb4 100644
--- a/lib/libthr/thread/thr_private.h
+++ b/lib/libthr/thread/thr_private.h
@@ -865,6 +865,8 @@ int	__sys_sigwaitinfo(const sigset_t *set, siginfo_t *info);
 
 /* #include <time.h> */
 #ifdef	_TIME_H_
+int	__sys_clock_nanosleep(clockid_t, int, const struct timespec *,
+	    struct timespec *);
 int	__sys_nanosleep(const struct timespec *, struct timespec *);
 #endif
 
diff --git a/lib/libthr/thread/thr_syscalls.c b/lib/libthr/thread/thr_syscalls.c
index 362826c..92d0c99 100644
--- a/lib/libthr/thread/thr_syscalls.c
+++ b/lib/libthr/thread/thr_syscalls.c
@@ -260,6 +260,22 @@ __thr_msync(void *addr, size_t len, int flags)
 }
 
 static int
+__thr_clock_nanosleep(clockid_t clock_id, int flags,
+    const struct timespec *time_to_sleep, struct timespec *time_remaining)
+{
+	struct pthread *curthread;
+	int ret;
+
+	curthread = _get_curthread();
+	_thr_cancel_enter(curthread);
+	ret = __sys_clock_nanosleep(clock_id, flags, time_to_sleep,
+	    time_remaining);
+	_thr_cancel_leave(curthread, 1);
+
+	return (ret);
+}
+
+static int
 __thr_nanosleep(const struct timespec *time_to_sleep,
     struct timespec *time_remaining)
 {
@@ -668,6 +684,7 @@ __thr_interpose_libc(void)
 	SLOT(ppoll);
 	SLOT(map_stacks_exec);
 	SLOT(fdatasync);
+	SLOT(clock_nanosleep);
 #undef SLOT
 	*(__libc_interposing_slot(
 	    INTERPOS__pthread_mutex_init_calloc_cb)) =