Add getthrname(2) manpage

ok jmc@ schwarze@

2 files changed, 149 insertions, 2 deletions

diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index 2f70b2b9463..a405654bca1 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile.inc,v 1.168 2023/01/07 05:24:58 guenther Exp $
+#	$OpenBSD: Makefile.inc,v 1.169 2023/01/08 04:54:50 guenther Exp $
 #	$NetBSD: Makefile.inc,v 1.35 1995/10/16 23:49:07 jtc Exp $
 #	@(#)Makefile.inc	8.1 (Berkeley) 6/17/93
 
@@ -185,7 +185,8 @@ MAN+=	__get_tcb.2 __thrsigdivert.2 __thrsleep.2 _exit.2 accept.2 \
 	getfh.2 getfsstat.2 getgid.2 getgroups.2 getitimer.2 getlogin.2 \
 	getpeername.2 getpgrp.2 getpid.2 getpriority.2 getrlimit.2 \
 	getrtable.2 getrusage.2 getsid.2 getsockname.2 getsockopt.2 \
-	getthrid.2 gettimeofday.2 getuid.2 intro.2 ioctl.2 issetugid.2 \
+	getthrid.2 getthrname.2 gettimeofday.2 getuid.2 \
+	intro.2 ioctl.2 issetugid.2 \
 	kbind.2 kill.2 kqueue.2 ktrace.2 link.2 listen.2 lseek.2 madvise.2 \
 	mimmutable.2 minherit.2 mkdir.2 mkfifo.2 mknod.2 mlock.2 \
 	mlockall.2 mmap.2 mount.2 mprotect.2 mquery.2 msyscall.2 msgctl.2 \
diff --git a/lib/libc/sys/getthrname.2 b/lib/libc/sys/getthrname.2
new file mode 100644
index 00000000000..86b3b72b128
--- /dev/null
+++ b/lib/libc/sys/getthrname.2
@@ -0,0 +1,146 @@
+.\"	$OpenBSD: getthrname.2,v 1.1 2023/01/08 04:54:50 guenther Exp $
+.\"
+.\" Copyright (c) 2023 Philip Guenther <guenther@openbsd.org>
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.Dd $Mdocdate: January 8 2023 $
+.Dt GETTHRNAME 2
+.Os
+.Sh NAME
+.Nm getthrname ,
+.Nm setthrname
+.Nd get and set thread name
+.Sh SYNOPSIS
+.In unistd.h
+.Ft int
+.Fo getthrname
+.Fa "pid_t tid"
+.Fa "char *name"
+.Fa "size_t namelen"
+.Fc
+.Ft int
+.Fo setthrname
+.Fa "pid_t tid"
+.Fa "const char *name"
+.Fc
+.Sh DESCRIPTION
+The
+.Fn getthrname
+system call stores the name of
+.Fa tid ,
+a thread in the current process,
+into the buffer
+.Fa name ,
+which must be of at least
+.Fa namelen
+bytes long.
+The buffer should be large enough to store the thread name and a
+trailing NUL
+(typically
+.Dv MAXCOMLEN+1
+bytes).
+The
+.Fn setthrname
+system call sets the name of
+.Fa tid
+to the supplied
+.Fa name .
+For both functions, if
+.Fa tid
+is zero then the current thread is operated on.
+.Pp
+Thread names have no inherent meaning in the system and are
+intended for display and debugging only.
+They are not secret but rather are visible to other processes using
+.Xr sysctl 2
+or
+.Xr kvm_getprocs 3
+and in
+.Ic ps Fl H
+output.
+.Pp
+After
+.Xr execve 2 ,
+the name of the process's only thread is reset to the empty string.
+Similarly, additional threads created with
+.Xr __tfork 3
+start with the empty name.
+After
+.Xr fork 2 ,
+the new process's only thread has the same name as the thread that
+invoked
+.Xr fork 2 .
+.Sh RETURN VALUES
+Upon successful completion, the value 0 is returned;
+otherwise the error number is returned.
+.Sh ERRORS
+.Fn getthrname
+and
+.Fn setthrname
+will succeed unless:
+.Bl -tag -width Er
+.It Bq Er EFAULT
+The
+.Fa name
+argument points to an
+invalid address.
+.El
+.Pp
+In addition,
+.Fn getthrname
+may return the following error:
+.Bl -tag -width Er
+.It Bq Er ERANGE
+The value of
+.Fa namelen
+is not large enough to store the thread name and a trailing NUL.
+.El
+.Pp
+.Fn setthrname
+may return the following errors:
+.Bl -tag -width Er
+.It Bq Er EINVAL
+The
+.Fa name
+argument
+pointed to a string that was too long.
+Thread names are limited to
+.Dv MAXCOMLEN
+characters, currently 23.
+.El
+.Sh SEE ALSO
+.Xr execve 2 ,
+.Xr fork 2 ,
+.Xr sysctl 2 ,
+.Xr __tfork 3 ,
+.Xr kvm_getprocs 3 ,
+.Xr pthread_set_name_np 3
+.Sh STANDARDS
+The
+.Fn getthrname
+and
+.Fn setthrname
+system calls are specific to
+.Ox ;
+.Xr pthread_get_name_np 3
+and
+.Xr pthread_set_name_np 3
+operate on the same thread name in a more portable way.
+.Sh HISTORY
+The
+.Fn getthrname
+and
+.Fn setthrname
+system calls first appeared in
+.Ox 7.3 .