Added a description of sticky directories.

SCCS-vsn: share/man/man8/sticky.8 6.2

diff --git a/usr/src/share/man/man8/sticky.8 b/usr/src/share/man/man8/sticky.8
index d54d4ab..a860cc0 100644 (file)
--- a/usr/src/share/man/man8/sticky.8
+++ b/usr/src/share/man/man8/sticky.8
@@ -2,15 +2,21 @@
 .\" All rights reserved.  The Berkeley software License Agreement
 .\" specifies the terms and conditions for redistribution.
 .\"
 .\" All rights reserved.  The Berkeley software License Agreement
 .\" specifies the terms and conditions for redistribution.
 .\"

-.\"    @(#)sticky.8    6.1 (Berkeley) %G%
+.\"    @(#)sticky.8    6.2 (Berkeley) %G%

 .\"
 .TH STICKY 8 ""
 .UC 4
 .SH NAME
 .\"
 .TH STICKY 8 ""
 .UC 4
 .SH NAME

-sticky \- executable files with persistent text
+sticky \- persistent text and append-only directories

 .SH DESCRIPTION
 .SH DESCRIPTION

-While the `sticky bit', mode 01000 (see
-.IR chmod (2)),
+The
+.I "sticky bit"
+(file mode bit 01000, see
+.IR chmod (2))
+is used to indicate special treatment
+for certain executable files and directories.
+.SH "STICKY TEXT EXECUTABLE FILES"
+While the `sticky bit'

 is set on a sharable executable file,
 the text of that file will not be removed from the system swap area.
 Thus the file does not have to be fetched from the file system
 is set on a sharable executable file,
 the text of that file will not be removed from the system swap area.
 Thus the file does not have to be fetched from the file system


@@ -20,14 +26,15 @@ original text cannot be overwritten in the file system,
 nor can the file be deleted.
 (Directory entries can be removed so long as one link remains.)
 .PP
 nor can the file be deleted.
 (Directory entries can be removed so long as one link remains.)
 .PP

-Sharable files are made by the
+Sharable executable files are made by the

 .B \-n
 and
 .B \-z
 options of
 .IR ld (1).
 .PP
 .B \-n
 and
 .B \-z
 options of
 .IR ld (1).
 .PP

-To replace a sticky file that has been used do:
+To replace a sticky text executable file that has been used,
+perform the following steps:

 (1) Clear the sticky bit with
 .IR chmod (1).
 (2) Execute the old program to flush the swapped copy.
 (1) Clear the sticky bit with
 .IR chmod (1).
 (2) Execute the old program to flush the swapped copy.


@@ -41,10 +48,37 @@ and
 .IR chown (2).
 (4) Set the sticky bit again.
 .PP
 .IR chown (2).
 (4) Set the sticky bit again.
 .PP

-Only the super-user can set the sticky bit.
-.SH BUGS
-Are self-evident.
+Only the super-user can set the sticky bit
+on a sharable executable file.
+.SH "STICKY DIRECTORIES"
+A directory whose `sticky bit' is set
+becomes an append-only directory, or, more accurately,
+a directory in which the deletion of files is restricted.
+A file in a sticky directory may only be removed or renamed
+by a user if the user has write permission for the directory and
+the user is the owner of the file, the owner of the directory,
+or the super-user.
+This feature is usefully applied to directories such as /tmp
+which must be publicly writable but
+should deny users the license to arbitrarily
+delete or rename each others' files.

 .PP
 .PP

-Is largely unnecessary on the VAX; matters only for large programs that
-will page heavily to start, since text pages are normally cached incore
+Any user may create a sticky directory.
+See
+.IR chmod (1)
+for details about modifying file modes.
+.SH BUGS
+Sticky text executable files are
+largely unnecessary on the VAX.
+The sticky attribute is useful only for large programs that
+will page heavily to start, since text pages are normally cached in core

 as long as possible after all instances of a text image exit.
 as long as possible after all instances of a text image exit.

+.PP
+Since the text areas of sticky text executables are stashed in the swap area,
+abuse of the feature can cause a system to run out of swap.
+.PP
+Neither
+.IR open (2)
+nor
+.IR mkdir (2)
+will create a file with the sticky bit set.