[pintos-anon] / doc / devel.texi

@node Development Tools
@appendix Development Tools

Here are some tools that you might find useful while developing code.

@menu
* Tags::                        
* cscope::                      
* CVS::                         
* SourceForge::                 
* VNC::                         
@end menu

@node Tags
@section Tags

Tags are an index to the functions and global variables declared in a
program.  Many editors, including Emacs and @command{vi}, can use
them.  The @file{Makefile} in @file{pintos/src} produces Emacs-style
tags with the command @code{make TAGS} or @command{vi}-style tags with
@code{make tags}.

In Emacs, use @kbd{M-.} to follow a tag in the current window,
@kbd{C-x 4 .} in a new window, or @kbd{C-x 5 .} in a new frame.  If
your cursor is on a symbol name for any of those commands, it becomes
the default target.  If a tag name has multiple definitions, @kbd{M-0
M-.} jumps to the next one.  To jump back to where you were before
you followed the last tag, use @kbd{M-*}.

@node cscope
@section cscope

The @command{cscope} program also provides an index to functions and
variables declared in a program.  It has some features that tag
facilities lack.  Most notably, it can find all the points in a
program at which a given function is called.

The @file{Makefile} in @file{pintos/src} produces @command{cscope}
indexes when it is invoked as @code{make cscope}.  Once the index has
been generated, run @command{cscope} from a shell command line; no
command-line arguments are normally necessary.  Then use the arrow
keys to choose one of the search criteria listed near the bottom of
the terminal, type in an identifier, and hit @key{Enter}.
@command{cscope} will then display the matches in the upper part of
the terminal.  You may use the arrow keys to choose a particular
match; if you then hit @key{Enter}, @command{cscope} will invoke the
default system editor@footnote{This is typically @command{vi}.  To
exit @command{vi}, type @kbd{: q @key{Enter}}.} and position the
cursor on that match.  To start a new search, type @key{Tab}.  To exit
@command{cscope}, type @kbd{Ctrl-d}.

Emacs and some versions of @command{vi} have their own interfaces to
@command{cscope}.  For information on how to use these interface,
visit @url{http://cscope.sourceforge.net, the @command{cscope} home
page}.

@node CVS
@section CVS

CVS is a version-control system.  That is, you can use it to keep
track of multiple versions of files.  The idea is that you do some
work on your code and test it, then check it into the version-control
system.  If you decide that the work you've done since your last
check-in is no good, you can easily revert to the last checked-in
version.  Furthermore, you can retrieve any old version of your code
as of some given day and time.  The version control logs tell you who
made changes and when.

CVS is not the best version control system out there, but it's
free, it's fairly easy to use, and
it's already available on the Leland machines you're using for
the projects.

For more information, visit the @uref{https://www.cvshome.org/, , CVS
home page}.

@menu
* Setting Up CVS::              
* Using CVS::                   
* CVS Locking::                 
@end menu

@node Setting Up CVS
@subsection Setting Up CVS

To set up CVS for use with Pintos on the Leland machines, start by
choosing one group member as the keeper of the CVS repository.
Everyone in the group will be able to use the CVS repository, but the
keeper will actually create the repository, keep its files in his or
her home directory, and maintain permissions for its contents.

The keeper has to perform several steps to set up the repository.
First, create a new AFS group for the repository by executing
@samp{pts creategroup @var{keeper}:pintos-cvs}, where @var{keeper} is
the keeper's Leland username.  Then, add each group member to the new
group by repeatedly using the command @samp{pts adduser -user
@var{username} -group @var{keeper}:pintos-cvs}, where @var{username}
is the name of a group member.  After the group is created and its
members added, @samp{pts membership @var{keeper}:pintos-cvs} should
report that each group member is a member of the
@samp{@var{keeper}:pintos-cvs} group.

The keeper now creates the repository directory and gives the group
members access to it.  We will assume that the repository will be in a
directory called @file{cvs} in the keeper's home directory.  First
create this directory with @samp{mkdir $HOME/cvs}, then give group
members access to it with @samp{fs setacl -dir $HOME/cvs -acl
@var{keeper}:pintos-cvs write}.  Group members also need to be able to
look up the @file{cvs} directory in the keeper's home directory, which
can be enabled via @samp{fs setacl -dir $HOME -acl
@var{keeper}:pintos-cvs l} (that's letter ``ell,'' not digit
``one.'').@footnote{This command will allow group members to list the
files in your home directory, but not read or write them.  It should not
create a security risk unless the names of files in your home directory
are secret.}

Now initialize the repository.
To initialize the repository, execute @samp{cvs -d $HOME/cvs init}.

Finally, import the Pintos sources into the newly initialized
repository.  If you have an existing set of Pintos sources you want to
add to the repository, @samp{cd} to its @samp{pintos} directory now.
Otherwise, to import the base Pintos source tree, @samp{cd} to
@file{/usr/class/cs140/pintos/pintos} (note the doubled
@samp{pintos}).  After changing the current directory, execute this
command:
@example
cvs -d $HOME/cvs import -m "Imported sources" pintos foobar start
@end example

Here is a summary of the commands you have now executed:

@example
pts creategroup @var{keeper}:pintos-cvs
pts adduser -user @var{username} -group @var{keeper}:pintos-cvs
mkdir $HOME/cvs
fs setacl -dir $HOME/cvs -acl @var{keeper}:pintos-cvs write
fs setacl -dir $HOME -acl @var{keeper}:pintos-cvs l
cvs -d $HOME/cvs init
cd /usr/class/cs140/pintos/pintos
cvs -d $HOME/cvs import -m "Imported sources" pintos foobar start
@end example

The repository is now ready for use by any group member, as described
below.  Keep in mind that the repository should only be accessed
using CVS commands---it is not generally useful to examine them by
hand, and you should definitely not modify them yourself.

@node Using CVS
@subsection Using CVS

To use CVS, start by check out a working copy of the contents of the
CVS repository into a directory named @file{@var{dir}}.  To do so, execute
@samp{cvs -d ~@var{keeper}/cvs checkout -d @var{dir} pintos}, where
@var{keeper} is the CVS keeper's Leland username.

(If this fails due to some kind of permission problem, then run
@command{aklog} and try again.  If it still doesn't work, log out and
back in.  If that still doesn't fix the problem, the CVS repository may
not be initialized properly.)

At this point, you can modify any of the files in the working copy.
You can see the changes you've made with @samp{cvs diff -u}.  If you
want to commit these changes back to the repository, making them
visible to the other group members, you can use the CVS commit
command.  Within the @file{pintos} directory, execute @samp{cvs
commit}.  This will figure out the files that have been changed and
fire up a text editor for you to describe the changes.  By default,
this editor is @file{vi}, but you can select a different editor by
setting the @env{CVSEDITOR} environment variable, e.g.@: with
@samp{setenv CVSEDITOR emacs} (add this line to your @file{.cvsrc} to
make it permanent).

Suppose another group member has committed changes.  You can see the
changes committed to the repository since the time you checked it out
(or updated from it) with @samp{cvs diff -u -r BASE -r HEAD}.  You can
merge those change into your working copy using @samp{cvs update}.  If
any of your local changes conflict with the committed changes, the CVS
command output should tell you.  In that case, edit the files that
contain conflicts, looking for @samp{<<<} and @samp{>>>} that denote
the conflicts, and fix the problem.

You can view the history of @var{file} in your working directory,
including the log messages, with @samp{cvs log @var{file}}.

You can give a particular set of file versions a name called a
@dfn{tag}.  First @samp{cd} to the root of the working copy, then
execute @samp{cvs tag @var{name}}.  It's best to have no local changes
in the working copy when you do this, because the tag will not include
uncommitted changes.  To recover the tagged repository later, use the
@samp{checkout} command in the form @samp{cvs -d ~@var{keeper}/cvs
checkout -r @var{tag} -d @var{dir} pintos}, where @var{keeper} is the
username of the CVS keeper and @var{dir} is the directory to put the
tagged repository into.

If you add a new file to the source tree, you'll need to add it to the
repository with @samp{cvs add @var{file}}.  This command does not have
lasting effect until the file is committed later with @samp{cvs
commit}.

To remove a file from the source tree, first remove it from the file
system with @command{rm}, then tell CVS with @samp{cvs remove
@var{file}}.  Again, only @samp{cvs commit} will make the change
permanent.

To discard your local changes for a given file, without committing
them, use @samp{cvs update -C @var{file}}.

To check out a version of your repository as of a particular date, use
the command @samp{cvs -d ~@var{keeper}/cvs checkout -D '@var{date}' -d
@var{dir} pintos}, where @var{keeper} is the username of the CVS
keeper and @var{dir} is the directory to put the tagged repository
into..  A typical format for @var{date} is @samp{YYYY-MM-DD HH:MM},
but CVS accepts several formats, even something like @samp{1 hour
ago}.

For more information, visit the @uref{https://www.cvshome.org/, , CVS
home page}.

@node CVS Locking
@subsection CVS Locking

You might occasionally see a message like this while using CVS:

@example
waiting for blp's lock in /afs/ir/users/b/l/blp/cvs
@end example

This normally means that more than one user is accessing the repository
at the same time.  CVS should automatically retry after 30 seconds, at
which time the operation should normally be able to continue.

If you encounter a long wait for a lock, of more than a minute or so, it
may indicate that a CVS command did not complete properly and failed to
remove its locks.  If you think that this is the case, ask the user in
question about it.  If it appears that an operation did go awry, then
you (or the named user) can delete files whose names start with
@file{#cvs.rfl}, @file{#cvs.wfl}, or @file{#cvs.lock} in the directory
mentioned in the message.  Doing so should allow your operation to
proceed.  Do not delete or modify other files.

@node SourceForge
@section SourceForge

SourceForge is a web-based system for facilitating software
development.  It provides you with a version-control system (typically
CVS, as described above) and other tools for tracking your software.
You can use it to store files, track bugs, and post notes about
development progress.  You can set up your own
project in SourceForge at @uref{http://sourceforge.net, ,
sourceforge.net}.

@node VNC
@section VNC

VNC stands for Virtual Network Computing.  It is, in essence, a remote
display system which allows you to view a computing ``desktop''
environment not only on the machine where it is running, but from
anywhere on the Internet and from a wide variety of machine
architectures.  It is already installed on the Leland machines.  For
more information, look at the @uref{http://www.realvnc.com/, , VNC
Home Page}.