ETCUPDATE(8) FreeBSD System Manager's Manual ETCUPDATE(8)
NAME
etcupdate - manage updates to system files not updated by installworld
SYNOPSIS
etcupdate [-npBF] [-d workdir] [-r | -s source | -t tarball]
[-A patterns] [-D destdir] [-I patterns] [-L logfile]
[-M options]
etcupdate build [-B] [-d workdir] [-s source] [-L logfile] [-M options]
tarball
etcupdate diff [-d workdir] [-D destdir] [-I patterns] [-L logfile]
etcupdate extract [-B] [-d workdir] [-s source | -t tarball] [-D destdir]
[-L logfile] [-M options]
etcupdate resolve [-p] [-d workdir] [-D destdir] [-L logfile]
etcupdate revert [-d workdir] [-D destdir] [-L logfile] file ...
etcupdate status [-d workdir] [-D destdir]
DESCRIPTION
The etcupdate utility is a tool for managing updates to files that are
not updated as part of `make installworld' such as files in /etc. It
manages updates by doing a three-way merge of changes made to these files
against the local versions. It is also designed to minimize the amount
of user intervention with the goal of simplifying upgrades for clusters
of machines.
To perform a three-way merge, etcupdate keeps copies of the current and
previous versions of files that it manages. These copies are stored in
two trees known as the "current" and "previous" trees. During a merge,
etcupdate compares the "current" and "previous" copies of each file to
determine which changes need to be merged into the local version of each
file. If a file can be updated without generating a conflict, etcupdate
will update the file automatically. If the local changes to a file
conflict with the changes made to a file in the source tree, then a merge
conflict is generated. The conflict must be resolved after the merge has
finished. The etcupdate utility will not perform a new merge until all
conflicts from an earlier merge are resolved.
MODES
The etcupdate utility supports several modes of operation. The mode is
specified via an optional command argument. If present, the command must
be the first argument on the command line. If a command is not
specified, the default mode is used.
Default Mode
The default mode merges changes from the source tree to the destination
directory. First, it updates the "current" and "previous" trees. Next,
it compares the two trees merging changes into the destination directory.
Finally, it displays warnings for any conditions it could not handle
automatically.
If the -r option is not specified, then the first step taken is to update
the "current" and "previous" trees. If a "current" tree already exists,
then that tree is saved as the "previous" tree. An older "previous" tree
is removed if it exists. By default the new "current" tree is built from
a source tree. However, if a tarball is specified via the -t option,
then the tree is extracted from that tarball instead.
Next, etcupdate compares the files in the "current" and "previous" trees.
If a file was removed from the "current" tree, then it will be removed
from the destination directory only if it does not have any local
modifications. If a file was added to the "current" tree, then it will
be copied to the destination directory only if it would not clobber an
existing file. If a file is changed in the "current" tree, then
etcupdate will attempt to merge the changes into the version of the file
in the destination directory. If the merge encounters conflicts, then a
version of the file with conflict markers will be saved for future
resolution. If the merge does not encounter conflicts, then the merged
version of the file will be saved in the destination directory. If
etcupdate is not able to safely merge in changes to a file other than a
merge conflict, it will generate a warning.
For each file that is updated a line will be output with a leading
character to indicate the action taken. The possible actions follow:
A Added
C Conflict
D Deleted
M Merged
U Updated
Finally, if any warnings were encountered they are displayed after the
merge has completed.
Note that for certain files etcupdate will perform post-install actions
any time that the file is updated. Specifically, pwd_mkdb(8) is invoked
if /etc/master.passwd is changed, cap_mkdb(1) is invoked to update
/etc/login.conf.db if /etc/login.conf is changed, newaliases(1) is
invoked if /etc/mail/aliases is changed, services_mkdb(8) is invoked if
/etc/services is changed, tzsetup(8) is invoked if /etc/localtime is
changed and if /var/db/zoneinfo exists, and /etc/rc.d/motd is invoked if
/etc/motd is changed. One exception is that if /etc/mail/aliases is
changed and the destination directory is not the default, then a warning
will be issued instead. This is due to a limitation of the newaliases(1)
command. Similarly, if /etc/motd is changed and the destination
directory is not the default, then /etc/rc.d/motd will not be executed
due to a limitation of that script. In this case no warning is issued as
the result of /etc/rc.d/motd is merely cosmetic and will be corrected on
the next reboot.
Build Mode
The build mode is used to build a tarball that contains a snapshot of a
"current" tree. This tarball can be used by the default and extract
modes. Using a tarball can allow etcupdate to perform a merge without
requiring a source tree that matches the currently installed world. The
tarball argument specifies the name of the file to create. The file will
be a tar(5) file compressed with bzip2(1).
Diff Mode
The diff mode compares the versions of files in the destination directory
to the "current" tree and generates a unified format diff of the changes.
This can be used to determine which files have been locally modified and
how. Note that etcupdate does not manage files that are not maintained
in the source tree such as /etc/fstab and /etc/rc.conf.
Extract Mode
The extract mode generates a new "current" tree. Unlike the default
mode, it does not save any existing "current" tree and does not modify
any existing "previous" tree. The new "current" tree can either be built
from a source tree or extracted from a tarball.
Resolve Mode
The resolve mode is used to resolve any conflicts encountered during a
merge. In this mode, etcupdate iterates over any existing conflicts
prompting the user for actions to take on each conflicted file. For each
file, the following actions are available:
(p) postpone Ignore this conflict for now.
(df) diff-full Show all changes made to the merged file as a unified
diff.
(e) edit Change the merged file in an editor.
(r) resolved Install the merged version of the file into the
destination directory.
(mf) mine-full Use the version of the file in the destination
directory and ignore any changes made to the file in
the "current" tree.
(tf) theirs-full Use the version of the file from the "current" tree and
discard any local changes made to the file.
(h) help Display the list of commands.
Revert Mode
The revert mode is used to restore the stock versions of files. In this
mode, etcupdate installs the stock version of requested files. This mode
cannot be used to restore directories, only individual files.
Status Mode
The status mode shows a summary of the results of the most recent merge.
First it lists any files for which there are unresolved conflicts. Next
it lists any warnings generated during the last merge. If the last merge
did not generate any conflicts or warnings, then nothing will be output.
OPTIONS
The following options are available. Note that most options do not apply
to all modes.
-A patterns Always install the new version of any files that match
any of the patterns listed in patterns. Each pattern
is evaluated as an sh(1) shell pattern. This option
may be specified multiple times to specify multiple
patterns. Multiple space-separated patterns may also
be specified in a single option. Note that ignored
files specified via the IGNORE_FILES variable or the
-I option will not be installed.
-B Do not build generated files in a private object tree.
Instead, reuse the generated files from a previously
built object tree that matches the source tree. This
can be useful to avoid gratuitous conflicts in
sendmail(8) configuration files when bootstrapping.
It can also be useful for building a tarball that
matches a specific world build.
-D destdir Specify an alternate destination directory as the
target of a merge. This is analogous to the DESTDIR
variable used with `make installworld'. The default
destination directory is an empty string which results
in merges updating /etc on the local machine.
-d workdir Specify an alternate directory to use as the work
directory. The work directory is used to store the
"current" and "previous" trees as well as unresolved
conflicts. The default work directory is
<destdir>/var/db/etcupdate.
-F Ignore changes in the FreeBSD ID string when comparing
files in the destination directory to files in either
of the "current" or "previous" trees. In diff mode,
this reduces noise due to FreeBSD ID string changes in
the output. During an update this can simplify
handling for harmless conflicts caused by FreeBSD ID
string changes.
Specifically, if a file in the destination directory
is identical to the same file in the "previous" tree
modulo the FreeBSD ID string, then the file is treated
as if it was unmodified and the "current" version of
the file will be installed. Similarly, if a file in
the destination directory is identical to the same
file in the "current" tree modulo the FreeBSD ID
string, then the "current" version of the file will be
installed to update the ID string. If the "previous"
and "current" versions of the file are identical, then
etcupdate will not change the file in the destination
directory.
Due to limitations in the diff(1) command, this option
may not have an effect if there are other changes in a
file that are close to the FreeBSD ID string.
-I patterns Ignore any files that match any of the patterns listed
in patterns. No warnings or other messages will be
generated for those files during a merge. Each
pattern is evaluated as an sh(1) shell pattern. This
option may be specified multiple times to specify
multiple patterns. Multiple space-separated patterns
may also be specified in a single option.
-L logfile Specify an alternate path for the log file. The
etcupdate utility logs each command that it invokes
along with the standard output and standard error to
this file. By default the log file is stored in a
file named log in the work directory.
-M options Pass options as additional parameters to make(1) when
building a "current" tree. This can be used for to
set the TARGET or TARGET_ARCH variables for a cross-
build.
-n Enable "dry-run" mode. Do not merge any changes to
the destination directory. Instead, report what
actions would be taken during a merge. Note that the
existing "current" and "previous" trees will not be
changed. If the -r option is not specified, then a
temporary "current" tree will be extracted to perform
the comparison.
-p Enable "pre-world" mode. Only merge changes to files
that are necessary to successfully run `make
installworld' or `make installkernel'. When this flag
is enabled, the existing "current" and "previous"
trees are left alone. Instead, a temporary tree is
populated with the necessary files. This temporary
tree is compared against the "current" tree. This
allows a normal update to be run after `make
installworld' has completed. Any conflicts generated
during a "pre-world" update should be resolved by a
"pre-world" resolve.
-r Do not update the "current" and "previous" trees
during a merge. This can be used to "re-run" a
previous merge operation.
-s source Specify an alternate source tree to use when building
or extracting a "current" tree. The default source
tree is /usr/src.
-t tarball Extract a new "current" tree from a tarball previously
generated by the build command rather than building
the tree from a source tree.
CONFIG FILE
The etcupdate utility can also be configured by setting variables in an
optional configuration file named /etc/etcupdate.conf. Note that command
line options override settings in the configuration file. The
configuration file is executed by sh(1), so it uses that syntax to set
configuration variables. The following variables can be set:
ALWAYS_INSTALL Always install files that match any of the patterns
listed in this variable similar to the -A option.
DESTDIR Specify an alternate destination directory similar to
the -D option.
EDITOR Specify a program to edit merge conflicts.
FREEBSD_ID Ignore changes in the FreeBSD ID string similar to
the -F option. This is enabled by setting the
variable to a non-empty value.
IGNORE_FILES Ignore files that match any of the patterns listed in
this variable similar to the -I option.
LOGFILE Specify an alternate path for the log file similar to
the -L option.
MAKE_OPTIONS Pass additional options to make(1) when building a
"current" tree similar to the -M option.
SRCDIR Specify an alternate source tree similar to the -s
option.
WORKDIR Specify an alternate work directory similar to the -d
option.
ENVIRONMENT
The etcupdate utility uses the program identified in the EDITOR
environment variable to edit merge conflicts. If EDITOR is not set,
vi(1) is used as the default editor.
FILES
/etc/etcupdate.conf Optional config file.
/var/db/etcupdate Default work directory used to store trees and
other data.
/var/db/etcupdate/log Default log file.
EXIT STATUS
The etcupdate utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
To compare the files in /etc with the stock versions:
etcupdate diff
To merge changes after an upgrade via the buildworld and installworld
process:
etcupdate
To resolve any conflicts generated during a merge:
etcupdate resolve
Bootstrapping
The etcupdate utility may need to be bootstrapped before it can be used.
The diff command will fail with an error about a missing reference tree
if bootstrapping is needed.
Bootstrapping etcupdate requires a source tree that matches the currently
installed world. The easiest way to ensure this is to bootstrap
etcupdate before updating the source tree to start the next world upgrade
cycle. First, generate a reference tree:
etcupdate extract
Second, use the diff command to compare the reference tree to your
current files in /etc. Undesired differences should be removed using an
editor, patch(1), or by copying files from the reference tree (located at
/var/db/etcupdate/current by default)
If the tree at /usr/src is already newer than the currently installed
world, a new tree matching the currently installed world can be checked
out to a temporary location. The reference tree for etcupdate can then
be generated via:
etcupdate extract -s /path/to/tree
The diff command can be used as above to remove undesired differences.
Afterwards, the changes in the tree at /usr/src can be merged via a
regular merge.
DIAGNOSTICS
The following warning messages may be generated during a merge. Note
that several of these warnings cover obscure cases that should occur
rarely if at all in practice. For example, if a file changes from a file
to a directory in the "current" tree and the file was modified in the
destination directory, then a warning will be triggered. In general,
when a warning references a pathname, the corresponding file in the
destination directory is not changed by a merge operation.
Directory mismatch: <path> (<type>) An attempt was made to create a
directory at path but an existing file of type "type" already exists for
that path name.
Modified link changed: <file> (<old> became <new>) The target of a
symbolic link named file was changed from "old" to "new" in the "current"
tree. The symbolic link has been modified to point to a target that is
neither "old" nor "new" in the destination directory.
Modified mismatch: <file> (<new> vs <dest>) A file named file of type
"new" was modified in the "current" tree, but the file exists as a
different type "dest" in the destination directory.
Modified <type> changed: <file> (<old> became <new>) A file named file
changed type from "old" in the "previous" tree to type "new" in the
"current" tree. The file in the destination directory of type "type" has
been modified, so it could not be merged automatically.
Modified <type> remains: <file> The file of type "type" named file has
been removed from the "current" tree, but it has been locally modified.
The modified version of the file remains in the destination directory.
Needs update: /etc/localtime (required manual update via tzsetup(8)) The
/var/db/zoneinfo file does not exist, so etcupdate was not able to
refresh /etc/localtime from its source file in /usr/share/zoneinfo.
Running tzsetup(8) will both refresh /etc/localtime and generate
/var/db/zoneinfo permitting future updates to refresh /etc/localtime
automatically.
Needs update: /etc/mail/aliases.db (required manual update via
newaliases(1)) The file /etc/mail/aliases was updated during a merge
with a non-empty destination directory. Due to a limitation of the
newaliases(1) command, etcupdate was not able to automatically update the
corresponding aliases database.
New file mismatch: <file> (<new> vs <dest>) A new file named file of
type "new" has been added to the "current" tree. A file of that name
already exists in the destination directory, but it is of a different
type "dest".
New link conflict: <file> (<new> vs <dest>) A symbolic link named file
has been added to the "current" tree that links to "new". A symbolic
link of the same name already exists in the destination directory, but it
links to a different target "dest".
Non-empty directory remains: <file> The directory file was removed from
the "current" tree, but it contains additional files in the destination
directory. These additional files as well as the directory remain.
Remove mismatch: <file> (<old> became <new>) A file named file changed
from type "old" in the "previous" tree to type "new" in the "current"
tree, but it has been removed in the destination directory.
Removed file changed: <file> A file named file was modified in the
"current" tree, but it has been removed in the destination directory.
Removed link changed: <file> (<old> became <new>) The target of a
symbolic link named file was changed from "old" to "new" in the "current"
tree, but it has been removed in the destination directory.
SEE ALSO
cap_mkdb(1), diff(1), make(1), newaliases(1), sh(1), mergemaster(8),
pwd_mkdb(8), services_mkdb(8), tzsetup(8)
HISTORY
The etcupdate utility first appeared in FreeBSD 10.0.
AUTHORS
The etcupdate utility was written by John Baldwin <jhb@FreeBSD.org>.
BUGS
Rerunning a merge does not automatically delete conflicts left over from
a previous merge. Any conflicts must be resolved before the merge can be
rerun. It is not clear if this is a feature or a bug.
There is no way to easily automate conflict resolution for specific
files. For example, one can imagine a syntax along the lines of
etcupdate resolve tf /some/file
to resolve a specific conflict in an automated fashion.
Bootstrapping etcupdate often results in gratuitous diffs in
/etc/mail/*.cf that cause conflicts in the first merge. If an object
tree that matches the source tree is present when bootstrapping, then
passing the -B flag to the extract command can work around this.
FreeBSD 13.1-RELEASE-p6 April 20, 2021 FreeBSD 13.1-RELEASE-p6
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