seccomp.2: Rework SECCOMP_GET_NOTIF_SIZES somewhat

The existing text says the structures (plural!) contain a 'struct
seccomp_data'. But this is only true for the received notification
structure (seccomp_notif). So, reword the sentence to be more
general, noting simply that the structures may evolve over time.

Add some comments to the structure definition.

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man2/seccomp.2 b/man2/seccomp.2
index c04d2c33ea282121493666ff01e6e9abe929c0ba..861a4219c44d9442791b77d93e7c450acb46ca62 100644 (file)
--- a/man2/seccomp.2
+++ b/man2/seccomp.2
@@ -264,9 +264,8 @@ must be a pointer to an unsigned 32-bit filter return action.
 .BR SECCOMP_GET_NOTIF_SIZES " (since Linux 5.0)"
 .\" commit 6a21cc50f0c7f87dae5259f6cfefe024412313f6
 Get the sizes of the seccomp user-space notification structures.
-Since the structures include a
-.I "struct seccomp_data"
-which may grow in size, this command can be used to determine how
+Since these structures may evolve and grow over time,
+this command can be used to determine how
 much memory to allocate for sending and receiving notifications.
 .IP
 The value of
@@ -277,15 +276,13 @@ must be a pointer to a
 .IR "struct seccomp_notif_sizes" ,
 which has the following form:
 .IP
-.in +4n
 .EX
 struct seccomp_notif_sizes
-    __u16 seccomp_notif;
-    __u16 seccomp_notif_resp;
-    __u16 seccomp_data;
+    __u16 seccomp_notif;      /* Size of notification structure */
+    __u16 seccomp_notif_resp; /* Size of response structure */
+    __u16 seccomp_data;       /* Size of \(aqstruct seccomp_data\(aq */
 };
 .EE
-.in
 .IP
 See
 .BR seccomp_user_notif (2)