The implementation of -flags was broken and did not match the (poorly)

documented behavior.  Only a certain set of file flags were recognized,
and "no" flags did not match files that have corresponding flags bits
turned off.

Fix and extend the -flags functionality as follows:

: -flags [-|+]<flags>,<notflags>
:    The flags are specified using symbolic names (see chflags(1)).
:    Those with the "no" prefix (except "nodump") are said to be
:    <notflags>.  Flags in <flags> are checked to be set, and flags in
:    <notflags> are checked to be not set.  Note that this is different
:    from -perm, which only allows the user to specify mode bits that
:    are set.
:
:    If flags are preceded by a dash (``-''), this primary evaluates
:    to true if at least all of the bits in <flags> and none of the bits
:    in <notflags> are set in the file's flags bits.  If flags are pre-
:    ceded by a plus (``+''), this primary evaluates to true if any of
:    the bits in <flags> is set in the file's flags bits, or any of the
:    bits in <notflags> is not set in the file's flags bits.  Otherwise,
:    this primary evaluates to true if the bits in <flags> exactly match
:    the file's flags bits, and none of the <flags> bits match those of
:    <notflags>.

MFC after:	2 weeks

1 files changed, 65 insertions, 20 deletions

diff --git a/usr.bin/find/find.1 b/usr.bin/find/find.1
index 99d496720985..5945d58e7bee 100644
--- a/usr.bin/find/find.1
+++ b/usr.bin/find/find.1
@@ -243,20 +243,50 @@ The filename substituted for
 the string
 .Dq Li {}
 is not qualified.
-.It Ic -flags Op Fl Ns Ar flags
-This primary evaluates to true if exactly those flags of the file are
-set which are also set using the specified
-.Ar flags
-(if these are not preceded by a dash
-.Pq Dq Li - ,
-or if they match the specified flags (if these are preceded by a dash).
-The
-.Ar flags
-are specified using symbolic names (see
+.It Ic -flags Oo Cm - Ns | Ns Cm + Oc Ns Ar flags , Ns Ar notflags
+The flags are specified using symbolic names (see
 .Xr chflags 1 ) .
+Those with the
+.Qq Li no
+prefix (except
+.Qq Li nodump )
+are said to be
+.Ar notflags .
+Flags in
+.Ar flags
+are checked to be set, and flags in
+.Ar notflags
+are checked to be not set.
 Note that this is different from
 .Ic -perm ,
-which only allows you to specify flags which are set.
+which only allows the user to specify mode bits that are set.
+.Pp
+If flags are preceded by a dash
+.Pq Dq Li - ,
+this primary evaluates to true
+if at least all of the bits in
+.Ar flags
+and none of the bits in
+.Ar notflags
+are set in the file's flags bits.
+If flags are preceded by a plus
+.Pq Dq Li + ,
+this primary evaluates to true
+if any of the bits in
+.Ar flags
+is set in the file's flags bits,
+or any of the bits in
+.Ar notflags
+is not set in the file's flags bits.
+Otherwise,
+this primary evaluates to true
+if the bits in
+.Ar flags
+exactly match the file's flags bits,
+and none of the
+.Ar flags
+bits match those of
+.Ar notflags .
 .It Ic -fstype Ar type
 True if the file is contained in a file system of type
 .Ar type .
@@ -428,29 +458,44 @@ Slashes
 .Pq Dq Li /
 are treated as normal characters and do not have to be
 matched explicitly.
-.It Ic -perm Oo Fl Oc Ns Ar mode
+.It Ic -perm Oo Cm - Ns | Ns Cm + Oc Ns Ar mode
 The
 .Ar mode
 may be either symbolic (see
 .Xr chmod 1 )
 or an octal number.
-If the mode is symbolic, a starting value of zero is assumed and the
-mode sets or clears permissions without regard to the process' file mode
+If the
+.Ar mode
+is symbolic, a starting value of zero is assumed and the
+.Ar mode
+sets or clears permissions without regard to the process' file mode
 creation mask.
-If the mode is octal, only bits 07777
+If the
+.Ar mode
+is octal, only bits 07777
 .Pq Dv S_ISUID | S_ISGID | S_ISTXT | S_IRWXU | S_IRWXG | S_IRWXO
 of the file's mode bits participate
 in the comparison.
-If the mode is preceded by a dash
+If the
+.Ar mode
+is preceded by a dash
 .Pq Dq Li - ,
 this primary evaluates to true
-if at least all of the bits in the mode are set in the file's mode bits.
-If the mode is preceded by a plus
+if at least all of the bits in the
+.Ar mode
+are set in the file's mode bits.
+If the
+.Ar mode
+is preceded by a plus
 .Pq Dq Li + ,
 this primary evaluates to true
-if any of the bits in the mode are set in the file's mode bits.
+if any of the bits in the
+.Ar mode
+are set in the file's mode bits.
 Otherwise, this primary evaluates to true if
-the bits in the mode exactly match the file's mode bits.
+the bits in the
+.Ar mode
+exactly match the file's mode bits.
 Note, the first character of a symbolic mode may not be a dash
 .Pq Dq Li - .
 .It Ic -print