In the following, `\n' refers to a linefeed and `\t' refers to a horizontal tab; requests are what the client sends and responses are what the server sends. In general, the connection is governed by the client--the server does not send responses without first receiving requests to do so; see section Introduction to Responses for more details of this convention.
It is typical, early in the connection, for the client to transmit a
Valid-responses request, containing all the responses it
supports, followed by a valid-requests request, which elicits
from the server a Valid-requests response containing all the
requests it understands. In this way, the client and server each find
out what the other supports before exchanging large amounts of data
(such as file contents).
Entries lines are transmitted as:
/ name / version / conflict / options / tag_or_date
tag_or_date is either `T' tag or `D' date or empty. If it is followed by a slash, anything after the slash shall be silently ignored.
version can be empty, or start with `0' or `-', for no user file, new user file, or user file to be removed, respectively.
conflict, if it starts with `+', indicates that the file had conflicts in it. The rest of conflict is `=' if the timestamp matches the file, or anything else if it doesn't. If conflict does not start with a `+', it is silently ignored.
options signifies the keyword expansion options (for example
`-ko'). In an Entry request, this indicates the options
that were specified with the file from the previous file updating
response (see section Introduction to Responses, for a list of file updating
responses); if the client is specifying the `-k' or `-A'
option to update, then it is the server which figures out what
overrides what.
A mode is any number of repetitions of
mode-type = data
separated by `,'.
mode-type is an identifier composed of alphanumeric characters. Currently specified: `u' for user, `g' for group, `o' for other (see below for discussion of whether these have their POSIX meaning or are more loose). Unrecognized values of mode-type are silently ignored.
data consists of any data not containing `,', `\0' or `\n'. For `u', `g', and `o' mode types, data consists of alphanumeric characters, where `r' means read, `w' means write, `x' means execute, and unrecognized letters are silently ignored.
The two most obvious ways in which the mode matters are: (1) is it writeable? This is used by the developer communication features, and is implemented even on OS/2 (and could be implemented on DOS), whose notion of mode is limited to a readonly bit. (2) is it executable? Unix CVS users need CVS to store this setting (for shell scripts and the like). The current CVS implementation on unix does a little bit more than just maintain these two settings, but it doesn't really have a nice general facility to store or version control the mode, even on unix, much less across operating systems with diverse protection features. So all the ins and outs of what the mode means across operating systems haven't really been worked out (e.g. should the VMS port use ACLs to get POSIX semantics for groups?).
In most contexts, `/' is used to separate directory and file names in filenames, and any use of other conventions (for example, that the user might type on the command line) is converted to that form. The only exceptions might be a few cases in which the server provides a magic cookie which the client then repeats verbatim, but as the server has not yet been ported beyond unix, the two rules provide the same answer (and what to do if future server ports are operating on a repository like e:/foo or CVS_ROOT:[FOO.BAR] has not been carefully thought out).
Characters outside the invariant ISO 646 character set should be avoided in filenames. This restriction may need to be relaxed to allow for characters such as `[' and `]' (see above about non-unix servers); this has not been carefully considered (and currently implementations probably use whatever character sets that the operating systems they are running on allow, and/or that users specify). Of course the most portable practice is to restrict oneself further, to the POSIX portable filename character set as specified in POSIX.1.
File contents (noted below as file transmission) can be sent in one of two forms. The simpler form is a number of bytes, followed by a linefeed, followed by the specified number of bytes of file contents. These are the entire contents of the specified file. Second, if both client and server support `gzip-file-contents', a `z' may precede the length, and the `file contents' sent are actually compressed with `gzip' (RFC1952/1951) compression. The length specified is that of the compressed version of the file.
In neither case are the file content followed by any additional data. The transmission of a file will end with a linefeed iff that file (or its compressed form) ends with a linefeed.
The encoding of file contents depends on the value for the `-k' option. If the file is binary (as specified by the `-kb' option in the appropriate place), then it is just a certain number of octets, and the protocol contributes nothing towards determining the encoding (using the file name is one widespread, if not universally popular, mechanism). If the file is text (not binary), then the file is sent as a series of lines, separated by linefeeds. If the keyword expansion is set to something other than `-ko', then it is expected that the file conform to the RCS expectations regarding keyword expansion--in particular, that it is in a character set such as ASCII in which 0x24 is a dollar sign (`$').
In various contexts, for example the Argument request and the
M response, one transmits what is essentially an arbitrary
string. Often this will have been supplied by the user (for example,
the `-m' option to the ci request). The protocol has no
mechanism to specify the character set of such strings; it would be
fairly safe to stick to the invariant ISO 646 character set but the
existing practice is probably to just transmit whatever the user
specifies, and hope that everyone involved agrees which character set is
in use, or sticks to a common subset.
The protocol contains times and dates in various places.
For the `-D' option to the annotate, co, diff,
export, history, rdiff, rtag, tag,
and update requests, the server should support two formats:
26 May 1997 13:01:40 GMT ; RFC 822 as modified by RFC 1123 5/26/1997 13:01:40 GMT ; traditional
The former format is preferred; the latter however is sent by the CVS command line client (versions 1.5 through at least 1.9).
For the `-d' option to the log request, servers should at
least support RFC 822/1123 format. Clients are encouraged to use this
format too (traditionally the command line CVS client has just passed
along the date format specified by the user, however).
For Mod-time, see the description of that response.
For Notify, see the description of that request.
By convention, requests which begin with a capital letter do not elicit a response from the server, while all others do -- save one. The exception is `gzip-file-contents'. Unrecognized requests will always elicit a response from the server, even if that request begins with a capital letter.
Here are the requests:
Root pathname \n
CVSROOT to use.
Note that pathname is a local directory and not a fully
qualified CVSROOT variable. pathname must
already exist; if creating a new root, use the init request, not
Root. pathname does not include the hostname of the
server, how to access the server, etc.; by the time the CVS protocol is
in use, connection, authentication, etc., are already taken care of.
The Root request must be sent only once, and it must be sent
before any requests other than Valid-responses,
valid-requests, UseUnchanged, or init.
Valid-responses request-list \n
valid-requests \n
Valid-requests response.
Directory local-directory \n
Entry and Modified and
also for ci and the other commands; normal usage is to send
Directory for each directory in which there will be an
Entry or Modified, and then a final Directory
for the original directory, then the command.
The local-directory is relative to
the top level at which the command is occurring (i.e. the last
Directory which is sent before the command);
to indicate that top level, `.' should be sent for
local-directory.
Here is an example of where a client gets repository and
local-directory. Suppose that there is a module defined by
moddir 1dirThat is, one can check out
moddir and it will take 1dir in
the repository and check it out to moddir in the working
directory. Then an initial check out could proceed like this:
C: Root /home/kingdon/zwork/cvsroot . . . C: Argument moddir C: Directory . C: /home/kingdon/zwork/cvsroot C: co S: Clear-sticky moddir/ S: /home/kingdon/zwork/cvsroot/1dir/ . . . S: okIn this example the response shown is
Clear-sticky, but it could
be another response instead. Note that it returns two pathnames.
The first one, `moddir/', indicates the working
directory to check out into. The second one, ending in `1dir/',
indicates the directory to pass back to the server in a subsequent
Directory request. For example, a subsequent update
request might look like:
C: Directory moddir C: /home/kingdon/zwork/cvsroot/1dir . . . C: updateFor a given local-directory, the repository will be the same for each of the responses, so one can use the repository from whichever response is most convenient. Typically a client will store the repository along with the sources for each local-directory, use that same setting whenever operating on that local-directory, and not update the setting as long as the local-directory exists. A client is free to rename a local-directory at any time (for example, in response to an explicit user request). While it is true that the server supplies a local-directory to the client, as noted above, this is only the default place to put the directory. Of course, the various
Directory requests for a single command (for example,
update or ci request) should name a particular directory
with the same local-directory.
Each Directory request specifies a brand-new
local-directory and repository; that is,
local-directory and repository are never relative to paths
specified in any previous Directory request.
Max-dotdot level \n
Directory requests are relative to will be
needed. For example, if the client is planning to use a
Directory request for `../../foo', it must send a
Max-dotdot request with a level of at least 2.
Max-dotdot must be sent before the first Directory
request.
Static-directory \n
Directory should not have
additional files checked out unless explicitly requested. The client
sends this if the Entries.Static flag is set, which is controlled
by the Set-static-directory and Clear-static-directory
responses.
Sticky tagspec \n
Directory has a sticky tag or date tagspec.
The first character of tagspec is `T' for a tag, or `D'
for a date. The remainder of tagspec contains the actual tag or
date.
The server should remember Static-directory and Sticky
requests for a particular directory; the client need not resend them
each time it sends a Directory request for a given directory.
However, the server is not obliged to remember them beyond the context
of a single command.
Checkin-prog program \n
Directory has a checkin program program.
Such a program would have been previously set with the
Set-checkin-prog response.
Update-prog program \n
Directory has an update program program.
Such a program would have been previously set with the
Set-update-prog response.
Entry entry-line \n
Directory. If the user
is operating on only some files in a directory, Entry requests
for only those files need be included. If an Entry request is
sent without Modified, Is-modified, or Unchanged,
it means the file is
lost (does not exist in the working directory). If both Entry
and one of Modified, Is-modified, or Unchanged are
sent for the same file, Entry must be sent first. For a
given file, one can send Modified, Is-modified, or
Unchanged, but not more than one of these three.
Kopt option \n
Modified or Is-modified
request (for example `-kb' for a binary file). This is similar to
Entry, but is used for a file for which there is no entries line.
Typically this will be a file being added via an add or
import request. The client may not send both Kopt and
Entry for the same file.
Modified filename \n
Directory. If
the user is operating on only some files in a directory, only those
files need to be included. This can also be sent without Entry,
if there is no entry for the file.
Is-modified filename \n
Modified,
but used if the server only needs
to know whether the file is modified, not the contents.
The commands which can take Is-modified instead of
Modified with no known change in behavior are: admin,
diff (if and only if two `-r' or `-D' options are
specified), watch-on, watch-off, watch-add,
watch-remove, watchers, editors,
log, and annotate.
For the status command, one can send Is-modified but if
the client is using imperfect mechanisms such as timestamps to determine
whether to consider a file modified, then the behavior will be
different. That is, if one sends Modified, then the server will
actually compare the contents of the file sent and the one it derives
from to determine whether the file is genuinely modified. But if one
sends Is-modified, then the server takes the client's word for
it. A similar situation exists for tag, if the `-c' option
is specified.
Commands for which Modified is necessary are co,
ci, update, and import.
Commands which do not need to inform the server about a working
directory, and thus should not be sending either Modified or
Is-modified: rdiff, rtag, history,
init, and release.
Commands for which further investigation is warranted are:
remove, add, and export. Pending such
investigation, the more conservative course of action is to stick to
Modified.
Unchanged filename \n
Directory.
UseUnchanged \n
Notify filename \n
edit or unedit command has taken
place. The server needs to send a Notified response, but such
response is deferred until the next time that the server is sending
responses. Response expected: no. Additional data:
notification-type \t time \t clienthost \t working-dir \t watches \nwhere notification-type is `E' for edit, `U' for unedit, undefined behavior if `C', and all other letters should be silently ignored for future expansion. time is the time at which the edit or unedit took place, in a user-readable format of the client's choice (the server should treat the time as an opaque string rather than interpreting it). clienthost is the name of the host on which the edit or unedit took place, and working-dir is the pathname of the working directory where the edit or unedit took place. watches are the temporary watches to set. If watches is followed by \t then the \t and the rest of the line should be ignored, for future expansion. Note that a client may be capable of performing an
edit or
unedit operation without connecting to the server at that time,
and instead connecting to the server when it is convenient (for example,
when a laptop is on the net again) to send the Notify requests.
Even if a client is capable of deferring notifications, it should
attempt to send them immediately (one can send Notify requests
together with a noop request, for example), unless perhaps if
it can know that a connection would be impossible.
Questionable filename \n
M response) `?' followed
by the directory and filename. filename must not contain
`/'; it needs to be a file in the directory named by the most
recent Directory request.
Case \n
Entry and Modified requests for the
same file must match in case regardless of whether the Case
request is sent. The latter mechanism is more general (it could also be
used for 8.3 filenames, VMS filenames with more than one `.', and
any other situation in which there is a predictable mapping between
filenames in the working directory and filenames in the protocol), but
there are some situations it cannot handle (ignore patterns, or
situations where the user specifies a filename and the client does not
know about that file).
Argument text \n
Argumentx text \n
Global_option option \n
valid-requests, it is probably better to
make new global options separate requests, rather than trying to add
them to this request.
Gzip-stream level \n
Kerberos-encrypt \n
Gzip-stream and
the Kerberos-encrypt requests are used, the
Kerberos-encrypt request should be used first. This will make
the client and server encrypt the compressed data, as opposed to
compressing the encrypted data. Encrypted data is generally
incompressible.
Note that this request does not fully prevent an attacker from hijacking
the connection, in the sense that it does not prevent hijacking the
connection between the initial authentication and the
Kerberos-encrypt request.
Gssapi-encrypt \n
Kerberos-encrypt, above, for
the relation between Gssapi-encrypt and Gzip-stream.
Note that this request does not fully prevent an attacker from hijacking
the connection, in the sense that it does not prevent hijacking the
connection between the initial authentication and the
Gssapi-encrypt request.
Gssapi-authenticate \n
Gssapi-authenticate
and Gssapi-encrypt has no effect beyond that of
Gssapi-encrypt. Unlike encrypted data, it is reasonable to
compress authenticated data.
Note that this request does not fully prevent an attacker from hijacking
the connection, in the sense that it does not prevent hijacking the
connection between the initial authentication and the
Gssapi-authenticate request.
Set variable=value \n
expand-modules \n
Module-expansion responses. Note
that the server can assume that this is checkout or export, not rtag or
rdiff; the latter do not access the working directory and thus have no
need to expand modules on the client side.
Expand may not be the best word for what this request does. It does not
necessarily tell you all the files contained in a module, for example.
Basically it is a way of telling you which working directories the
server needs to know about in order to handle a checkout of the
specified modules.
For example, suppose that the server has a module defined by
aliasmodule -a 1dirThat is, one can check out
aliasmodule and it will take
1dir in the repository and check it out to 1dir in the
working directory. Now suppose the client already has this module
checked out and is planning on using the co request to update it.
Without using expand-modules, the client would have two bad
choices: it could either send information about all working
directories under the current directory, which could be unnecessarily
slow, or it could be ignorant of the fact that aliasmodule stands
for 1dir, and neglect to send information for 1dir, which
would lead to incorrect operation.
With expand-modules, the client would first ask for the module to
be expanded:
C: Root /home/kingdon/zwork/cvsroot . . . C: Argument aliasmodule C: Directory . C: /home/kingdon/zwork/cvsroot C: expand-modules S: Module-expansion 1dir S: okand then it knows to check the `1dir' directory and send requests such as
Entry and Modified for the files in that
directory.
ci \n
diff \n
tag \n
status \n
log \n
admin \n
history \n
watchers \n
editors \n
annotate \n
Argument, Directory, Entry, or
Modified requests, if they have been sent. The
last Directory sent specifies the working directory at the time
of the operation. No provision is made for any input from the user.
This means that ci must use a -m argument if it wants to
specify a log message.
co \n
Argument, Directory, Entry, or
Modified requests, if they have been sent. Arguments to this
command are module names; the client cannot know what directories they
correspond to except by (1) just sending the co request, and then
seeing what directory names the server sends back in its responses, and
(2) the expand-modules request.
export \n
Argument, Directory, Entry, or
Modified requests, if they have been sent. Arguments to this
command are module names, as described for the co request. The
intention behind this command is that a client can get sources from a
server without storing CVS information about those sources. That is, a
client probably should not count on being able to take the entries line
returned in the Created response from an export request
and send it in a future Entry request. Note that the entries
line in the Created response must indicate whether the file is
binary or text, so the client can create it correctly.
rdiff \n
rtag \n
Argument requests, if they have been sent. The client
should not send Directory, Entry, or Modified
requests for this command; they are not used. Arguments to these
commands are module names, as described for co.
init root-name \n
CVSROOT variable. The
Root request need not have been previously sent.
update \n
cvs update command. This
uses any previous Argument, Directory, Entry,
or Modified requests, if they have been sent. The
last Directory sent specifies the working directory at the time
of the operation. The -I option is not used--files which the
client can decide whether to ignore are not mentioned and the client
sends the Questionable request for others.
import \n
cvs import command. This
uses any previous Argument, Directory, Entry, or
Modified requests, if they have been sent. The
last Directory sent specifies the working directory at the time
of the operation. The files to be imported are sent in Modified
requests (files which the client knows should be ignored are not sent;
the server must still process the CVSROOT/cvsignore file unless -I ! is
sent). A log message must have been specified with a -m
argument.
add \n
Argument, Directory, Entry, or
Modified requests, if they have been sent. The
last Directory sent specifies the working directory at the time
of the operation.
To add a directory, send the directory to be added using
Directory and Argument requests. For example:
C: Root /u/cvsroot . . . C: Argument nsdir C: Directory nsdir C: /u/cvsroot/1dir/nsdir C: Directory . C: /u/cvsroot/1dir C: add S: M Directory /u/cvsroot/1dir/nsdir added to the repository S: okYou will notice that the server does not signal to the client in any particular way that the directory has been successfully added. The client is supposed to just assume that the directory has been added and update its records accordingly. Note also that adding a directory is immediate; it does not wait until a
ci request as files do.
To add a file, send the file to be added using a Modified
request. For example:
C: Argument nfile C: Directory . C: /u/cvsroot/1dir C: Modified nfile C: u=rw,g=r,o=r C: 6 C: hello C: add S: E cvs server: scheduling file `nfile' for addition S: Mode u=rw,g=r,o=r S: Checked-in ./ S: /u/cvsroot/1dir/nfile S: /nfile/0/// S: E cvs server: use 'cvs commit' to add this file permanently S: okNote that the file has not been added to the repository; the only effect of a successful
add request, for a file, is to supply the client
with a new entries line containing `0' to indicate an added file.
In fact, the client probably could perform this operation without
contacting the server, although using add does cause the server
to perform a few more checks.
The client sends a subsequent ci to actually add the file to the
repository.
Another quirk of the add request is that with CVS 1.9 and older,
a pathname specified in
an Argument request cannot contain `/'. There is no good
reason for this restriction, and in fact more recent CVS servers don't
have it.
But the way to interoperate with the older servers is to ensure that
all Directory requests for add (except those used to add
directories, as described above), use `.' for
local-directory. Specifying another string for
local-directory may not get an error, but it will get you strange
Checked-in responses from the buggy servers.
remove \n
Argument, Directory, Entry, or
Modified requests, if they have been sent. The
last Directory sent specifies the working directory at the time
of the operation.
Note that this request does not actually do anything to the repository;
the only effect of a successful remove request is to supply the
client with a new entries line containing `-' to indicate a removed
file. In fact, the client probably could perform this operation without
contacting the server, although using remove may cause the server
to perform a few more checks.
The client sends a subsequent ci request to actually record the
removal in the repository.
watch-on \n
watch-off \n
watch-add \n
watch-remove \n
cvs watch on, cvs
watch off, cvs watch add, and cvs watch remove commands,
respectively. This uses any previous Argument,
Directory, Entry, or Modified
requests, if they have been sent. The last Directory sent
specifies the working directory at the time of the operation.
release \n
cvs release command has
taken place and update the history file accordingly.
noop \n
Notified responses, etc.
update-patches \n
update
request. The client must issue the -u argument to update
in order to receive patches.
gzip-file-contents level \n
Gzip-stream is suggested
instead of gzip-file-contents as it gives better compression; the
only reason to implement the latter is to provide compression with
CVS 1.8 and earlier. The gzip-file-contents request asks
the server to compress files it sends to the client using gzip
(RFC1952/1951) compression, using the specified level of compression.
If this request is not made, the server must not compress files.
This is only a hint to the server. It may still decide (for example, in
the case of very small files, or files that already appear to be
compressed) not to do the compression. Compression is indicated by a
`z' preceding the file length.
Availability of this request in the server indicates to the client that
it may compress files sent to the server, regardless of whether the
client actually uses this request.
wrapper-sendme-rcsOptions \n
Wrapper-rcsOption responses.
other-request text \n
When the client is done, it drops the connection.
After a command which expects a response, the server sends however many of the following responses are appropriate. The server should not send data at other times (the current implementation may violate this principle in a few minor places, where the server is printing an error message and exiting--this should be investigated further).
Any set of responses always ends with `error' or `ok'. This indicates that the response is over.
The responses Checked-in, New-entry, Updated,
Created, Update-existing, Merged, and
Patched are refered to as file updating responses, because
they change the status of a file in the working directory in some way.
The responses Mode, Mod-time, and Checksum are
referred to as file update modifying responses because they modify
the next file updating response. In no case shall a file update
modifying response apply to a file updating response other than the next
one. Nor can the same file update modifying response occur twice for
a given file updating response (if servers diagnose this problem, it may
aid in detecting the case where clients send an update modifying
response without following it by a file updating response).
Many of the responses contain something called pathname.
The name is somewhat misleading; it actually indicates a pair of
pathnames. First, a local directory name
relative to the directory in which the command was given (i.e. the last
Directory before the command). Then a linefeed and a repository
name. Then
a slash and the filename (without a `,v' ending).
For example, for a file `i386.mh'
which is in the local directory `gas.clean/config' and for which
the repository is `/rel/cvsfiles/devo/gas/config':
gas.clean/config/ /rel/cvsfiles/devo/gas/config/i386.mh
If the server wants to tell the client to create a directory, then it
merely uses the directory in any response, as described above, and the
client should create the directory if it does not exist. Note that this
should only be done one directory at a time, in order to permit the
client to correctly store the repository for each directory. Servers
can use requests such as Clear-sticky,
Clear-static-directory, or any other requests, to create
directories.
Some server
implementations may poorly distinguish between a directory which should
not exist and a directory which contains no files; in order to refrain
from creating empty directories a client should both send the `-P'
option to update or co, and should also detect the case in
which the server asks to create a directory but not any files within it
(in that case the client should remove the directory or refrain from
creating it in the first place). Note that servers could clean this up
greatly by only telling the client to create directories if the
directory in question should exist, but until servers do this, clients
will need to offer the `-P' behavior described above.
Here are the responses:
Valid-requests request-list \n
Checked-in pathname \n
New-entry pathname \n
Checked-in, but the
file is not up to date.
Updated pathname \n
Created and
Update-existing are supported.
Created pathname \n
Updated and takes the same additional data, but
is used only if no Entry, Modified, or
Unchanged request has been sent for the file in question. The
distinction between Created and Update-existing is so
that the client can give an error message in several cases: (1) there is
a file in the working directory, but not one for which Entry,
Modified, or Unchanged was sent (for example, a file which
was ignored, or a file for which Questionable was sent), (2)
there is a file in the working directory whose name differs from the one
mentioned in Created in ways that the client is unable to use to
distinguish files. For example, the client is case-insensitive and the
names differ only in case.
Update-existing pathname \n
Updated and takes the same additional data, but
is used only if a Entry, Modified, or Unchanged
request has been sent for the file in question.
This response, or Merged, indicates that the server has
determined that it is OK to overwrite the previous contents of the file
specified by pathname. Provided that the client has correctly
sent Modified or Is-modified requests for a modified file,
and the file was not modified while CVS was running, the server can
ensure that a user's modifications are not lost.
Merged pathname \n
Updated and takes the same additional data,
with the one difference that after the new copy of the file is enclosed,
it will still not be up to date. Used for the results of a merge, with
or without conflicts.
It is useful to preserve an copy of what the file looked like before the
merge. This is basically handled by the server; before sending
Merged it will send a Copy-file response. For example, if
the file is `aa' and it derives from revision 1.3, the
Copy-file response will tell the client to copy `aa' to
`.#aa.1.3'. It is up to the client to decide how long to keep this
file around; traditionally clients have left it around forever, thus
letting the user clean it up as desired. But another answer, such as
until the next commit, might be preferable.
Rcs-diff pathname \n
Updated and takes the same additional data,
with the one difference that instead of sending a new copy of the file,
the server sends an RCS change text. This change text is produced by
`diff -n' (the GNU diff `-a' option may also be used). The
client must apply this change text to the existing file. This will only
be used when the client has an exact copy of an earlier revision of a
file. This response is only used if the update command is given
the `-u' argument.
Patched pathname \n
Rcs-diff and takes the same additional data,
except that it sends a standard patch rather than an RCS change text.
The patch is produced by `diff -c' for CVS 1.6 and later (see
POSIX.2 for a description of this format), or `diff -u' for
previous versions of CVS; clients are encouraged to accept either
format. Like Rcs-diff, this response is only used if the
update command is given the `-u' argument.
The Patched response is deprecated in favor of the
Rcs-diff response. However, older clients (CVS 1.9 and earlier)
only support Patched.
Mode mode \n
Checked-in. Mode is a file update modifying response
as described in section Introduction to Responses.
Mod-time time \n
Mod-time is a file update modifying response
as described in section Introduction to Responses.
The
time is in the format specified by RFC822 as modified by RFC1123.
The server may specify any timezone it chooses; clients will want to
convert that to their own timezone as appropriate. An example of this
format is:
26 May 1997 13:01:40 -0400There is no requirement that the client and server clocks be synchronized. The server just sends its recommendation for a timestamp (based on its own clock, presumably), and the client should just believe it (this means that the time might be in the future, for example).
Checksum checksum\n
Checksum is a file update modifying response
as described in section Introduction to Responses).
In the case of
Patched, the checksum applies to the file after being patched,
not to the patch itself. The client should compute the checksum itself,
after receiving the file or patch, and signal an error if the checksums
do not match. The checksum is the 128 bit MD5 checksum represented as
32 hex digits (MD5 is described in RFC1321).
This response is optional, and is only used if the
client supports it (as judged by the Valid-responses request).
Copy-file pathname \n
CVS/Entries.
This can optionally be implemented as a rename instead of a copy. The
only use for it which currently has been identified is prior to a
Merged response as described under Merged. Clients can
probably assume that is how it is being used, if they want to worry
about things like how long to keep the newname file around.
Removed pathname \n
Remove-entry pathname \n
CVS/Entries, but the file
itself is already gone (this happens in response to a ci request
which involves committing the removal of a file).
Set-static-directory pathname \n
Entries.Static flag, which
it should then send back to the server in a Static-directory
request whenever the directory is operated on. pathname ends in a
slash; its purpose is to specify a directory, not a file within a
directory.
Clear-static-directory pathname \n
Set-static-directory, but clear, not set, the flag.
Set-sticky pathname \n
Sticky request for
future operations. pathname ends in a slash; its purpose is to
specify a directory, not a file within a directory. The client should
store tagspec and pass it back to the server as-is, to allow for
future expansion. The first character of tagspec is `T' for
a tag, `D' for a date, or something else for future expansion. The
remainder of tagspec contains the actual tag or date.
Clear-sticky pathname \n
Set-sticky.
Template pathname \n
Set-checkin-prog dir \n
Checkin-prog request
for future operations.
Set-update-prog dir \n
Update-prog request
for future operations.
Notified pathname \n
Notify
request; if there are several Notify requests for a single file,
the requests should be processed in order; the first Notified
response pertains to the first Notify request, etc.
Module-expansion pathname \n
co request (for example, if the modules file
contains the `-d' option, it will be the directory specified with
`-d', not the name of the module).
Wrapper-rcsOption pattern -k 'option' \n
Valid-responses).
M text \n
Mbinary \n
E text \n
M but send to stderr not stdout.
F \n
MT tagname data \n
+bold +italic text -italic
-bold but not +bold +italic text
-bold -italic). A particular start and end tag may be
documented to constrain the tagged text responses which are valid
between them.
Note that if data is present there will always be exactly one
space between tagname and data; if there is more than one
space, then the spaces beyond the first are part of data.
Here is an example of some tagged text responses. Note that there is
a trailing space after `Checking in' and `initial revision:'
and there are two trailing spaces after `<--'. Such trailing
spaces are, of course, part of data.
MT +checking-in MT text Checking in MT fname gz.tst MT text ; MT newline MT rcsfile /home/kingdon/zwork/cvsroot/foo/gz.tst,v MT text <-- MT fname gz.tst MT newline MT text initial revision: MT init-rev 1.1 MT newline MT text done MT newline MT -checking-inIf the client does not support the `MT' response, the same responses might be sent as:
M Checking in gz.tst; M /home/kingdon/zwork/cvsroot/foo/gz.tst,v <-- gz.tst M initial revision: 1.1 M doneFor a list of specific tags, see section Tags for the MT tagged text response.
error errno-code ` ' text \n
ENOENT); if the server doesn't support this
feature, or if it's not appropriate for this particular message, it just
omits the errno-code (in that case there are two spaces after
`error'). Text is an error message such as that provided by
strerror(), or any other message the server wants to use.
ok \n
The MT response, as described in section Responses, offers a
way for the server to send tagged text to the client. This section
describes specific tags. The intention is to update this section as
servers add new tags.
In the following descriptions, text and newline tags are
omitted. Such tags contain information which is intended for users (or
to be discarded), and are subject to change at the whim of the server.
To avoid being vulnerable to such whim, clients should look for the tags
listed here, not text, newline, or other tags.
The following tag means to indicate to the user that a file has been
updated. It is more or less redundant with the Created and
Update-existing responses, but we don't try to specify here
whether it occurs in exactly the same circumstances as Created
and Update-existing. The name is the pathname of the file
being updated relative to the directory in which the command is
occurring (that is, the last Directory request which is sent
before the command).
MT +updated MT fname name MT -updated
Here is an example; lines are prefixed by `C: ' to indicate the client sends them or `S: ' to indicate the server sends them.
The client starts by connecting, sending the root, and completing the protocol negotiation. In actual practice the lists of valid responses and requests would be longer.
C: Root /u/cvsroot C: Valid-responses ok error Checked-in M E C: valid-requests S: Valid-requests Root Directory Entry Modified Argument Argumentx ci co S: ok C: UseUnchanged
The client wants to check out the supermunger module into a fresh
working directory. Therefore it first expands the supermunger
module; this step would be omitted if the client was operating on a
directory rather than a module.
C: Argument supermunger C: Directory . C: /u/cvsroot C: expand-modules
The server replies that the supermunger module expands to the
directory supermunger (the simplest case):
S: Module-expansion supermunger S: ok
The client then proceeds to check out the directory. The fact that it
sends only a single Directory request which specifies `.'
for the working directory means that there is not already a
supermunger directory on the client.
C: Argument -N C: Argument supermunger C: Directory . C: /u/cvsroot C: co
The server replies with the requested files. In this example, there is
only one file, `mungeall.c'. The Clear-sticky and
Clear-static-directory requests are sent by the current
implementation but they have no effect because the default is for those
settings to be clear when a directory is newly created.
S: Clear-sticky supermunger/
S: /u/cvsroot/supermunger/
S: Clear-static-directory supermunger/
S: /u/cvsroot/supermunger/
S: E cvs server: Updating supermunger
S: M U supermunger/mungeall.c
S: Created supermunger/
S: /u/cvsroot/supermunger/mungeall.c
S: /mungeall.c/1.1///
S: u=rw,g=r,o=r
S: 26
S: int mein () { abort (); }
S: ok
The current client implementation would break the connection here and make a new connection for the next command. However, the protocol allows it to keep the connection open and continue, which is what we show here.
After the user modifies the file and instructs the client to check it back in. The client sends arguments to specify the log message and file to check in:
C: Argument -m C: Argument Well, you see, it took me hours and hours to find C: Argumentx this typo and I searched and searched and eventually C: Argumentx had to ask John for help. C: Argument mungeall.c
It also sends information about the contents of the working directory,
including the new contents of the modified file. Note that the user has
changed into the `supermunger' directory before executing this
command; the top level directory is a user-visible concept because the
server should print filenames in M and E responses
relative to that directory.
C: Directory .
C: /u/cvsroot/supermunger
C: Entry /mungeall.c/1.1///
C: Modified mungeall.c
C: u=rw,g=r,o=r
C: 26
C: int main () { abort (); }
And finally, the client issues the checkin command (which makes use of the data just sent):
C: ci
And the server tells the client that the checkin succeeded:
S: M Checking in mungeall.c; S: E /u/cvsroot/supermunger/mungeall.c,v <-- mungeall.c S: E new revision: 1.2; previous revision: 1.1 S: E done S: Mode u=rw,g=r,o=r S: Checked-in ./ S: /u/cvsroot/supermunger/mungeall.c S: /mungeall.c/1.2/// S: ok
The following are part of every known implementation of the CVS protocol
(except obsolete, pre-1.5, versions of CVS) and it is considered
reasonable behavior to completely fail to work if you are connected with
an implementation which attempts to not support them. Requests:
Root, Valid-responses, valid-requests,
Directory, Entry, Modified, Unchanged,
Argument, Argumentx, ci, co, update.
Responses: ok, error, Valid-requests,
Checked-in, Updated, Merged, Removed,
M, E.
A server need not implement Repository, but in order to interoperate
with CVS 1.5 through 1.9 it must claim to implement it (in
Valid-requests). The client will not actually send the request.
This section briefly describes protocol elements which are obsolete. There is no attempt to document them in full detail.
There was a Repository request which was like Directory
except it only provided repository, and the local directory was
assumed to be similarly named.
If the UseUnchanged request was not sent, there was a Lost
request which was sent to indicate that a file did not exist in the
working directory, and the meaning of sending Entries without
Lost or Modified was different. All current clients (CVS
1.5 and later) will send UseUnchanged if it is supported.
Go to the first, previous, next, last section, table of contents.