APPLYLOG(8)APPLYLOG(8)NAME
applylog, updatelog - log-based updates
SYNOPSIS
install/applylog [ -c ] [ -e ] [ -n ] [ -s ] [ -u ] [ -g ] [ -v ] [ -T
timefile ] clientlog clientroot serverroot [ path ... ]
install/updatelog [ -p proto ] [ -r root ] [ -t now gen ] [ -c ] [ -x
path ] log [ path ... ]
DESCRIPTION
These two commands allow distribution of updates (eg, to the Inferno
tree) based on a log of changes since a previous update. Notionally,
one server system is the primary for a set of files, and one or more
client systems maintain replicas of that set, although in some applica‐
tions server and client might be the same machine.
Applylog is run on a client, to update the file tree rooted at client‐
root. The server's version of the tree is rooted at serverroot on the
client, typically by being mounted there (see bind(1)). Applylog takes
the current state of the replica from the entries in clientlog, and
applies a set of changes represented by log entries read from its stan‐
dard input. Those entries are provided by the server. Each change is
examined to see whether the file to which it applies is in the expected
state. If so, the change is applied without comment; otherwise, there
is a conflict caused by a local change to the replica tree indepen‐
dently from the primary. By default, applylog diagnoses the conflict
and does not apply the change. It accepts the following options:
-c Resolve inconsistencies in favour of the client: leave the
replica as is.
-e Exit with an error status on any error, including inconsistency
between client and server.
-n Print on standard output a list of changes that would be made,
and list any conflicts, but do not change the tree or update the
log.
-s Resolve inconsistencies in favour of the server: make the
replica match the server's state.
-u Make file ownership in the replica match that on the server.
-g Make group ownership in the replica match that on the server.
-v Print a summary of each log entry as it is examined.
-T timefile
Read a time and sequence number from timefile and apply only log
entries with stamps greater than that. On successful comple‐
tion, if the -n option is not given, update the timefile with
the stamp of the last log entry processed successfully.
The scope of an update in a tree can be restricted to a particular set
of paths listed on the command line. They should all be relative path
names.
Updatelog is run on a server to produce a sequence of log entries rep‐
resenting changes to the primary tree since a previous log was pro‐
duced. It can also be run on a client to see how its replica state
differs from that recorded in a log. It accepts the following options:
-p proto
Use proto as the prototype for the file system, as described by
proto(6) (default: /lib/proto/all).
-r root
The replica is rooted at root (default: the current directory,
.).
-t now gen
Make log entries use time now and initial sequence number gen.
The defaults are the current time and 0.
-c Produce output only for content and metadata changes, not addi‐
tions or deletions.
-x path
Exclude path and its subtrees from consideration.
By default, updatelog produces log entries describing changes, addi‐
tions and deletions to all files in root but the scope can be limited
by giving a different proto, explicitly listing trees to consider as
paths on the command line, and by giving one or more -x options to
exclude particular paths, in any desired combination.
Log file format
A log file is a text file with one line representing each change to the
tree. Each line has the form:
time gen verb path serverpath mode uid gid mtime length [ sum
... ]
where:
time, gen
are decimal numbers that order the sequence of requests:
time is typically the time in seconds of the epoch at
which the entry was made; gen is a monotonically increas‐
ing sequence number
verb is an action:
a add file path
c change the contents of file path
d delete path
m change the metadata (permissions, ownership) for
path
path the name of the file on the client
serverpath
the name of the file on the server with the contents for
path, or simply when the server and client file names are
the same
mode, uid, gid, length, mtime
the resulting metadata (except for d where the metadata
is that for the file to be deleted)
sum is the MD5 checksum of the file's contents
SOURCE
/appl/cmd/install/applylog.b
/appl/cmd/install/logs.b
/appl/cmd/install/updatelog.b
SEE ALSOfs(1), kfs(4), proto(6)APPLYLOG(8)
