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TMPREAPER(8) System Manager's Manual TMPREAPER(8)
NAME
tmpreaper - removes files which haven't been accessed for a period of time
SYNOPSIS
tmpreaper [-htvfmMsaT] [--help] [--test] [--verbose] [--force] [--delay=x] [--runtime=x]
[--showdeleted] [--ctime] [--mtime] [--mtime-dir] [--symlinks] [--all] [[--protect
'<shell_pattern>']...] <time_spec> <dirs>...
DESCRIPTION
tmpreaper recursively searches for and removes files and empty directories which haven't
been accessed for a given number of seconds. Normally, it's used to clean up directories
which are used for temporary holding space, such as "/tmp". Please read the WARNINGS sec-
tion of this manual.
When changing directories, tmpreaper is very sensitive to possible race condition security
exploits[1], and will exit with an error if one is detected. It does not follow symbolic
links in the directories it's cleaning (even if a symbolic link is given as its argument),
never performs chdir(".."), will not switch file systems, and only removes empty directo-
ries and regular files. Unless your machine is one with lots of relatively untrusted
users, such as an ISP or school, you don't need this program; `find ... -exec rm ...'
works just as well when you don't have to be concerned about people trying to exploit the
race condition on you.
tmpreaper will stop itself after almost one minute with an appropriate warning message, as
attempts to keep it running long enough so that it runs in parallel with another instance
of itself may also lead to possible vulnerabilities. Normally, tmpreaper won't need that
amount of time. If your system is so slow that it does, try to configure things so that
this doesn't happen. As a last resort, the --runtime=x option can be used to set the num-
ber of seconds after which the timeout occurs; the default setting is 55 seconds.
tmpreaper dates files by their atime, not their mtime, unless you select the --mtime op-
tion. If files aren't being removed when ls -l implies they should be, use stat(1) or ls
--time=access to examine the file's atime and see if that helps to explain the problem.
Additionally, tmpreaper can be instructed to also check the ctime (inode change time,
which is updated e.g. when the file is created or permissions are changed). This is pri-
marily useful when tmpreaper is used to clean up directories that are accessible as a
Samba share; DOS (and Windows) PCs preserve the mtime and the atime when copying to a new
file, so that it appears that the newly created file is old. tmpreaper will remove such
files is the atime is beyond the removal time, even though they were just created. This is
avoided by using the --ctime option.
As testing the contents of subdirectories will update those directories' atime, empty di-
rectories won't be removed. To circumvent this problem you can use the --mtime-dir option,
which will switch on mtime checking for directories only. Using --mtime-dir in addition to
--mtime doesn't do anything useful.
The <time_spec> parameter defines the age threshold for removing files. If the file has
not been accessed for <time_spec>, it becomes eligible for removal. The <time_spec>
should be a number, defaulting to hours, optionally suffixed by one character: `d' for
days, `h' for hours, `m' for minutes, or `s' for seconds. Following the time option, one
or more directories must be given for tmpreaper to clean up.
On linux ext2/ext3/ext4 filesystems, no errors will be given when trying to remove files
marked as immutable. A common situation for this was the ext3 .journal file. However,
there may of course be other files marked as such by the system administrator.
OPTIONS
<noargs>, -h, --help
Print a brief version, copyright, and usage statement on stderr, then exit with er-
ror status 1.
-t, --test
Don't actually remove any files, but go through the motions, checking through the
directory, then pretend to remove the eligible files.
-v, --verbose
Print a verbose display. Two levels of verbosity are available---use this option
twice to get the most verbose output. The --test option automaticly sets --verbose
once.
Higher numbers mean more output (max. is 3).
To force normal verbosity after --test, use "--verbose=0". This will generally
only show error messages. Use "--test --verbose=0 --showdeleted" to give a
shellscript-like list of actions that would have been done (see the --showdeleted
description below).
--showdeleted
Show what files and directories are deleted. The output is in the form of shell
commands, i.e. "rm /dir/dir2/file" and "rmdir /dir/dir2".
When used together with --test, this option will still cause the "shell commands"
to be printed, although nothing is really done. Note that this may show more than
without --test, as problems removing the file won't be detected (e.g. immutable
files).
-f, --force
Remove files even if EUID doesn't have write access (akin to rm -f). Normally,
files owned by the current EUID, with no write bit set are not removed.
--delay=x
Delay execution at the start for a random time, up to x seconds; if no value is
specified, the default maximum time to delay is 256 seconds. This is an option
useful in cron scripts to make the execution of tmpreaper less predictable, thus
making things a little harder for those who would attempt to use tmpreaper to
thwart security.
-T x, --runtime=x
Execution of tmpreaper will aborted after x seconds; this is to prevent attacks
that create many, many files. By default the timeout is set to 55 seconds. A
value of 0 will disable this feature, which is not advised as this feature prevents
possible race-conditions between different instances of tmpreaper.
-m, --mtime
Base the decision of whether to remove the file on its mtime, rather than on its
atime.
-M, --mtime-dir
Base the decision of whether to remove the directory on its mtime, rather than on
its atime.
-c, --ctime
Base the decision of whether to remove the file on its ctime, in addition to its
atime. Only applicable if the --mtime options is not given!
-s, --symlinks
Remove symlinks too, not just regular files and directories.
-a, --all
Remove all file types, not just regular files, symlinks, and directories.
--protect '<shell_pattern>'
Protect the files that match the <shell_pattern> from deletion. This option may be
used more than once. It has no one letter abbreviation, you must spell out the
full word "protect".
If you do not enclose the <shell_pattern> in single quotes, the shell will perform
the expansion before tmpreaper reads its argument array. The program does not sup-
port that syntax, so you must use single quotes around the glob pattern.
tmpreaper will chdir(2) into each of the directories you've specified for cleanup,
and check for files matching the <shell_pattern> there. It then builds a list of
them, and uses that to protect them from removal. For example:
tmpreaper --test --verbose --protect \
'.X*-{lock,unix,unix/*}' --protect '.ICE-{unix{/*,}}' \
5d /tmp # 5 day grace period
TIPS
As long as there are files present inside a subdirectory, it won't get removed. You can
use a non-writable, self-owned file, perhaps named ".tmpreaper", or, if you are su, a file
that has the ext2fs immutable attribute set, to keep a subdirectory from being deleted.
Of course, you could just as easily use use the --protect option to obtain the same re-
sult.
Because the command line argument processing is implemented with GNU getopt_long(3)[2],
you may order the arguments thusly, if it pleases you:
tmpreaper --test --verbose 5h \
--protect './tmp/{blah?,dir{/blah4,}}' ./tmp \
--protect '/tmp/.X*' /tmp
... Note that if you use --all or --symlinks, it will have global effect. If you only
want it turned on for one directory, you must use separate commands.
WARNINGS
Please do not ever run tmpreaper on `/'!!! There are no safeguards against this built into
the program, because that would make it difficult to use in a chrooted environment.
SEE ALSO
chattr(1) chdir(2) chroot(8) cron(1) getopt_long(3) ls(1) lsattr(1) rm(1) stat(1)
[1] http://seclists.org/lists/bugtraq/1996/May/0046.html or
http://www.security-express.com/archives/bugtraq/1996_2/0054.html
http://linuxgazette.net/18/tmp.html
(formerly http://www.linuxgazette.com/issue18/tmp.html)
http://linuxgazette.net/20/followup.html
[2] info:(libc)Long Options
AUTHOR
Karl M. Hegbloom <karlheg AT debian.org>
Mostly based on `tmpwatch-1.2/1.4', by:
Erik Troan <ewt AT redhat.com>
Now being maintained for Debian by:
Paul Slootman <paul AT debian.org>
4th Berkeley Distribution Sat Jan 5 2019 TMPREAPER(8)
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