Document PT_IO

1 files changed, 39 insertions, 1 deletions

diff --git a/lib/libc/sys/ptrace.2 b/lib/libc/sys/ptrace.2
index cda3c16163b..975cc1acf49 100644
--- a/lib/libc/sys/ptrace.2
+++ b/lib/libc/sys/ptrace.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ptrace.2,v 1.8 2000/10/18 05:12:11 aaron Exp $
+.\"	$OpenBSD: ptrace.2,v 1.9 2002/03/11 14:36:27 art Exp $
 .\"	$NetBSD: ptrace.2,v 1.3 1996/02/23 01:39:41 jtc Exp $
 .\"
 .\" This file is in the public domain.
@@ -176,6 +176,44 @@ except that it does not allow
 specifying an alternate place to continue execution, and after it
 succeeds, the traced process is no longer traced and continues
 execution normally.
+.It Dv PT_IO
+This request is a more general interface that can be used instead of
+.Dv PT_READ_D ,
+.Dv PT_WRITE_D ,
+.Dv PT_READ_I
+and
+.Dv PT_WRITE_I .
+The I/O request is encoded in a
+.Dq Li "struct ptrace_io_desc"
+defined as:
+.Bd -literal -offset indent -compact
+struct ptrace_io_desc {
+	int     piod_op;
+	void    *piod_offs;
+	void    *piod_addr;
+	size_t  piod_len;
+};
+.Ed
+Where
+.Fa piod_offs
+is the offset within the traced process where the I/O operation should be
+made,
+.Fa piod_addr
+is the buffer in the parent and
+.Fa piod_len is the length of the I/O request.
+The
+.Fa piod_op
+member specifies what operation that needs to be done.
+Possible values are:
+.Bl -tag -width 18n
+.It PIOD_OP_READ_DATA
+.It PIOD_OP_WRITE_DATA
+.It PIOD_OP_READ_TEXT
+.It PIOD_OP_WRITE_TEXT
+.El
+See also the description of
+.Dv PT_READ_I
+for the difference between DATA and TEXT spaces.
 .El
 .Pp
 Additionally, machine-specific requests can exist.