While reading file(1)'s code in #openbsd-daily mulander noted that the
'name' and 'use' types were missing from magic(5).
I'm not entirely sure yet whether this is complete, so here's what I
did:
magic(5) provided by devel/magic documents version 5.31 while base's
magic(5) is at 4.24. Here are the types found in 5.31 but not ours as
well as those of the missing ones that are actually implemented but
undocumented as of now:
$ grep -i "TYPE_($(grep -F 'It Dv' $(man -w magic) |
cut -d' ' -f3 | sort | uniq -u | paste -sd\| - |
tee /dev/stderr))" magic.h
beid3|beqwdate|clear|indirect|leid3|leqwdate|name|qwdate|use
MAGIC_TYPE_CLEAR,
MAGIC_TYPE_NAME,
MAGIC_TYPE_USE,
What about the current version being 4.21? We're clearly ahead of this,
it seems magic(5) wasn't updated when nicm@ reimplemented things.
This patch documents the respective types.
Feedback/OK?
Index: magic.5
===================================================================
RCS file: /cvs/src/usr.bin/file/magic.5,v
retrieving revision 1.17
diff -u -p -r1.17 magic.5
--- magic.5 24 Apr 2016 07:02:07 -0000 1.17
+++ magic.5 29 Jun 2017 17:41:56 -0000
@@ -218,6 +218,31 @@ This is intended to be used with the tes
.Em x
(which is always true) and a message that is to be used if there are
no other matches.
+.It Dv clear
+This test is always true and clears the match flag for that continuation
+level.
+It is intended to be used with the default test.
+.It Dv name
+Define a
+.Dq named
+magic instance that can be called from another
+.Dv use
+magic entry, like a subroutine call.
+Named instance direct magic offsets are relative to the offset of the
+previous matched entry, but indirect offsets are relative to the
+beginning of the file as usual.
+Named magic entries always match.
+.It Dv use
+Recursively call the named magic starting from the current offset.
+If the name of the referenced begins with a
+.Dv ^
+then the endianness of the magic is switched; if the magic mentioned
+.Dv leshort
+for example,
+it is treated as
+.Dv beshort
+and vice versa.
+This is useful to avoid duplicating the rules for different endianness.
.El
.Pp
Each top-level magic pattern (see below for an explanation of levels)
