TMPFILES.D(5) tmpfiles.d TMPFILES.D(5)
NAME
tmpfiles.d - Configuration for creation, deletion and cleaning of
volatile and temporary files
SYNOPSIS
/etc/tmpfiles.d/*.conf
/run/tmpfiles.d/*.conf
/usr/lib/tmpfiles.d/*.conf
DESCRIPTION
systemd-tmpfiles uses the configuration files from the above
directories to describe the creation, cleaning and removal of volatile
and temporary files and directories which usually reside in directories
such as /run or /tmp.
Volatile and temporary files and directories are those located in /run
(and its alias /var/run), /tmp, /var/tmp, the API file systems such as
/sys or /proc, as well as some other directories below /var.
System daemons frequently require private runtime directories below
/run to place communication sockets and similar in. For these, consider
declaring them in their unit files using RuntimeDirectory= (see
systemd.exec(5) for details), if this is feasible.
CONFIGURATION FORMAT
Each configuration file shall be named in the style of package.conf or
package-part.conf. The second variant should be used when it is
desirable to make it easy to override just this part of configuration.
Files in /etc/tmpfiles.d override files with the same name in
/usr/lib/tmpfiles.d and /run/tmpfiles.d. Files in /run/tmpfiles.d
override files with the same name in /usr/lib/tmpfiles.d. Packages
should install their configuration files in /usr/lib/tmpfiles.d. Files
in /etc/tmpfiles.d are reserved for the local administrator, who may
use this logic to override the configuration files installed by vendor
packages. All configuration files are sorted by their filename in
lexicographic order, regardless of which of the directories they reside
in. If multiple files specify the same path, the entry in the file with
the lexicographically earliest name will be applied. All other
conflicting entries will be logged as errors. When two lines are prefix
and suffix of each other, then the prefix is always processed first,
the suffix later. Otherwise, the files/directories are processed in the
order they are listed.
If the administrator wants to disable a configuration file supplied by
the vendor, the recommended way is to place a symlink to /dev/null in
/etc/tmpfiles.d/ bearing the same filename.
The configuration format is one line per path containing type, path,
mode, ownership, age, and argument fields:
#Type Path Mode UID GID Age Argument
d /run/user 0755 root root 10d -
L /tmp/foobar - - - - /dev/null
Type
The type consists of a single letter and optionally an exclamation
mark.
The following line types are understood:
f
Create a file if it does not exist yet. If the argument parameter
is given, it will be written to the file.
F
Create or truncate a file. If the argument parameter is given, it
will be written to the file.
w
Write the argument parameter to a file, if the file exists. Lines
of this type accept shell-style globs in place of normal path
names. The argument parameter will be written without a trailing
newline. C-style backslash escapes are interpreted.
d
Create a directory if it does not exist yet.
D
Create or empty a directory.
e
Clean directory contents based on the age argument. Lines of this
type accept shell-style globs in place of normal path names.
v
Create a subvolume if the path does not exist yet and the file
system supports this (btrfs). Otherwise create a normal directory,
in the same way as d.
p, p+
Create a named pipe (FIFO) if it does not exist yet. If suffixed
with + and a file already exists where the pipe is to be created,
it will be removed and be replaced by the pipe.
L, L+
Create a symlink if it does not exist yet. If suffixed with + and a
file already exists where the symlink is to be created, it will be
removed and be replaced by the symlink. If the argument is omitted,
symlinks to files with the same name residing in the directory
/usr/share/factory/ are created. Note that permissions and
ownership on symlinks are ignored.
c, c+
Create a character device node if it does not exist yet. If
suffixed with + and a file already exists where the device node is
to be created, it will be removed and be replaced by the device
node. It is recommended to suffix this entry with an exclamation
mark to only create static device nodes at boot, as udev will not
manage static device nodes that are created at runtime.
b, b+
Create a block device node if it does not exist yet. If suffixed
with + and a file already exists where the device node is to be
created, it will be removed and be replaced by the device node. It
is recommended to suffix this entry with an exclamation mark to
only create static device nodes at boot, as udev will not manage
static device nodes that are created at runtime.
C
Recursively copy a file or directory, if the destination files or
directories do not exist yet. Note that this command will not
descend into subdirectories if the destination directory already
exists. Instead, the entire copy operation is skipped. If the
argument is omitted, files from the source directory
/usr/share/factory/ with the same name are copied.
x
Ignore a path during cleaning. Use this type to exclude paths from
clean-up as controlled with the Age parameter. Note that lines of
this type do not influence the effect of r or R lines. Lines of
this type accept shell-style globs in place of normal path names.
X
Ignore a path during cleaning. Use this type to exclude paths from
clean-up as controlled with the Age parameter. Unlike x, this
parameter will not exclude the content if path is a directory, but
only directory itself. Note that lines of this type do not
influence the effect of r or R lines. Lines of this type accept
shell-style globs in place of normal path names.
r
Remove a file or directory if it exists. This may not be used to
remove non-empty directories, use R for that. Lines of this type
accept shell-style globs in place of normal path names.
R
Recursively remove a path and all its subdirectories (if it is a
directory). Lines of this type accept shell-style globs in place of
normal path names.
z
Adjust the access mode, group and user, and restore the SELinux
security context of a file or directory, if it exists. Lines of
this type accept shell-style globs in place of normal path names.
Z
Recursively set the access mode, group and user, and restore the
SELinux security context of a file or directory if it exists, as
well as of its subdirectories and the files contained therein (if
applicable). Lines of this type accept shell-style globs in place
of normal path names.
t
Set extended attributes. Lines of this type accept shell-style
globs in place of normal path names. This can be useful for setting
SMACK labels.
T
Recursively set extended attributes. Lines of this type accept
shell-style globs in place of normal path names. This can be useful
for setting SMACK labels.
a, a+
Set POSIX ACLs (access control lists). If suffixed with +,
specified entries will be added to the existing set.
systemd-tmpfiles will automatically add the required base entries
for user and group based on the access mode of the file, unless
base entries already exist or are explictly specified. The mask
will be added if not specified explicitly or already present. Lines
of this type accept shell-style globs in place of normal path
names. This can be useful for allowing additional access to certain
files.
A, A+
Same as a and a+, but recursive.
If the exclamation mark is used, this line is only safe of execute
during boot, and can break a running system. Lines without the
exclamation mark are presumed to be safe to execute at any time, e.g.
on package upgrades. systemd-tmpfiles will execute line with an
exclamation mark only if option --boot is given.
For example:
# Make sure these are created by default so that nobody else can
d /tmp/.X11-unix 1777 root root 10d
# Unlink the X11 lock files
r! /tmp/.X[0-9]*-lock
The second line in contrast to the first one would break a running
system, and will only be executed with --boot.
Path
The file system path specification supports simple specifier expansion.
The following expansions are understood:
Table 1. Specifiers available
+----------+----------------+---------------------+
|Specifier | Meaning | Details |
+----------+----------------+---------------------+
|"%m" | Machine ID | The machine ID of |
| | | the running system, |
| | | formatted as |
| | | string. See |
| | | machine-id(5) for |
| | | more information. |
+----------+----------------+---------------------+
|"%b" | Boot ID | The boot ID of the |
| | | running system, |
| | | formatted as |
| | | string. See |
| | | random(4) for more |
| | | information. |
+----------+----------------+---------------------+
|"%H" | Host name | The hostname of the |
| | | running system. |
+----------+----------------+---------------------+
|"%v" | Kernel release | Identical to uname |
| | | -r output. |
+----------+----------------+---------------------+
|"%%" | Escaped % | Single percent |
| | | sign. |
+----------+----------------+---------------------+
Mode
The file access mode to use when creating this file or directory. If
omitted or when set to "-", the default is used: 0755 for directories,
0644 for all other file objects. For z, Z lines, if omitted or when set
to "-", the file access mode will not be modified. This parameter is
ignored for x, r, R, L, t, and a lines.
Optionally, if prefixed with "~", the access mode is masked based on
the already set access bits for existing file or directories: if the
existing file has all executable bits unset, all executable bits are
removed from the new access mode, too. Similarly, if all read bits are
removed from the old access mode, they will be removed from the new
access mode too, and if all write bits are removed, they will be
removed from the new access mode too. In addition, the sticky/SUID/SGID
bit is removed unless applied to a directory. This functionality is
particularly useful in conjunction with Z.
UID, GID
The user and group to use for this file or directory. This may either
be a numeric user/group ID or a user or group name. If omitted or when
set to "-", the default 0 (root) is used. For z, Z lines, when omitted
or when set to "-", the file ownership will not be modified. These
parameters are ignored for x, r, R, L, t, and a lines.
Age
The date field, when set, is used to decide what files to delete when
cleaning. If a file or directory is older than the current time minus
the age field, it is deleted. The field format is a series of integers
each followed by one of the following postfixes for the respective time
units: s, m or min, h, d, w, ms, us, respectively meaning seconds,
minutes, hours, days, weeks, milliseconds, and microseconds. Full names
of the time units can be used too.
If multiple integers and units are specified, the time values are
summed. If an integer is given without a unit, s is assumed.
When the age is set to zero, the files are cleaned unconditionally.
The age field only applies to lines starting with d, D, e and x. If
omitted or set to "-", no automatic clean-up is done.
If the age field starts with a tilde character "~", the clean-up is
only applied to files and directories one level inside the directory
specified, but not the files and directories immediately inside it.
Argument
For L lines determines the destination path of the symlink. For c, b
determines the major/minor of the device node, with major and minor
formatted as integers, separated by ":", e.g. "1:3". For f, F, and w
may be used to specify a short string that is written to the file,
suffixed by a newline. For C, specifies the source file or directory.
For t determines extended attributes to be set. For a determines ACL
attributes to be set. Ignored for all other lines.
EXAMPLE
Example 1. /etc/tmpfiles.d/screen.conf example
screen needs two directories created at boot with specific modes and
ownership.
d /run/screens 1777 root root 10d
d /run/uscreens 0755 root root 10d12h
t /run/screen - - - - user.name="John Smith" security.SMACK64=screen
Example 2. /etc/tmpfiles.d/abrt.conf example
abrt needs a directory created at boot with specific mode and ownership
and its content should be preserved.
d /var/tmp/abrt 0755 abrt abrt
x /var/tmp/abrt/*
SEE ALSO
systemd(1), systemd-tmpfiles(8), systemd-delta(1), systemd.exec(5),
attr(5), getfattr(1), setfattr(1), setfacl(1), getfacl(1)
systemd 219 TMPFILES.D(5)
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