with a symmetric RC4 session key. For each user of paraslash you must
create a public/secret RSA key pair for authentication.
+If para_client is started without non-option arguments, an interactive
+session (shell) is started. Command history and command completion are
+supported through libreadline.
*para_audiod*
The client program which talks to para_audiod. Used to control
para_audiod, to receive status info, or to grab the stream at any
-point of the decoding process.
+point of the decoding process. Like para_client, para_audioc supports
+interactive sessions on systems with libreadline.
*para_recv*
git clone git://git.tuebingen.mpg.de/osl
- - XREFERENCE(ftp://ftp.gnu.org/pub/gnu/gcc, gcc). The
- EMPH(gnu compiler collection) is usually shipped with the
- distro. gcc-3.3 or newer is required.
+ - XREFERENCE(ftp://ftp.gnu.org/pub/gnu/gcc, gcc) or
+ XREFERENCE(http://clang.llvm.org, clang). All gcc versions
+ >= 3.3 are currently supported. Clang version 1.1 or newer
+ should work as well.
- XREFERENCE(ftp://ftp.gnu.org/pub/gnu/make, gnu make) is
also shipped with the disto. On BSD systems the gnu make
scripts which run during compilation require the EMPH(Bourne
again shell). It is most likely already installed.
- - XREFERENCE(http://www.openssl.org/, openssl). The EMPH(Secure
- Sockets Layer) library is needed for cryptographic routines
- on both the server and the client side. It is usually shipped
- with the distro, but you might have to install the "development
- package" (called libssl-dev on debian systems) as well.
+ - XREFERENCE(http://www.openssl.org/, openssl) or
+ XREFERENCE(ftp://ftp.gnupg.org/gcrypt/libgcrypt/, libgcrypt).
+ At least one of these two libraries is needed as the backend
+ for cryptographic routines on both the server and the client
+ side. Both openssl and libgcrypt are usually shipped with the
+ distro, but you might have to install the development package
+ (libssl-dev or libgcrypt-dev on debian systems) as well.
+
+ - XREFERENCE(ftp://ftp.gnu.org/pub/gnu/gengetopt/, gengetopt)
+ is needed to generate the C code for the command line parsers
+ of all paraslash executables.
- XREFERENCE(ftp://ftp.gnu.org/pub/gnu/help2man, help2man)
is used to create the man pages.
libao). Needed to build the ao writer (ESD, PulseAudio,...).
Debian package: libao-dev.
+ - XREFERENCE(http://cnswww.cns.cwru.edu/php/chet/readline/rltop.html,
+ GNU Readline). If this library (libreadline-dev) is installed,
+ para_client and para_audioc support interactive sessions.
+
Installation
~~~~~~~~~~~~
- para_client connects to para_server and sends an
authentication request for a user. It does so by connecting
- to para_server, TCP 2990, the control port of para_server.
+ to TCP port 2990 of the server host. This port is called the
+ para_server _control port_.
- para_server accepts the connection and forks a child process
- which is supposed to handle the connection. The parent process
- keeps listening on the control port while the child process
- (also called para_server below) continues as follows.
+ which handles the incoming request. The parent process keeps
+ listening on the control port while the child process (also
+ called para_server below) continues as follows.
- para_server loads the RSA public key of that user, fills a
fixed-length buffer with random bytes, encrypts that buffer
session key.
- para_client receives the encrypted buffer and decrypts it
- using the user's private key, thereby obtaining the challenge
+ with the user's private key, thereby obtaining the challenge
buffer and the session key. It sends the SHA1 hash value of
the challenge back to para_server and stores the session key
for further use.
this point on the communication is encrypted using the RC4
stream cipher with the session key known to both peers.
-paraslash relies on the quality of openssl's cryptographically strong
-pseudo-random bytes, on the security of the implementation of the
-openssl RSA and RC4 crypto routines and on the infeasibility to invert
-the SHA1 function.
+paraslash relies on the quality of the pseudo-random bytes provided
+by the crypto library (openssl or libgcrypt), on the security of
+the implementation of the RSA and RC4 crypto routines and on the
+infeasibility to invert the SHA1 function.
Neither para_server or para_client create RSA keys on their own. This
has to be done once for each user as sketched in REFERENCE(Quick start,
The user_list file
~~~~~~~~~~~~~~~~~~
-At startup para_server reads the user list file which must contain
-one line per user. The default location of the user list file may be
+At startup para_server reads the user list file which contains one
+line per user. The default location of the user list file may be
changed with the --user_list option.
There should be at least one user in this file. Each user must have
maintains tables containing images (e.g. album cover art) and lyrics
that can be associated with one or more audio files.
-AFS uses libosl, the object storage layer, as the backend library
-for storing information on audio files, playlists, etc. This library
-offers functionality similar to a relational database, but is much
-more lightweight than a full database backend.
+AFS uses XREFERENCE(http://systemlinux.org/~maan/osl/, libosl), the
+object storage layer library, as the backend library for storing
+information on audio files, playlists, etc. This library offers
+functionality similar to a relational database, but is much more
+lightweight than a full database backend.
In this chapter we sketch the setup of the REFERENCE(The AFS process,
AFS process) during server startup and proceed with the description
in detail and contains pratical examples. The way REFERENCE(File
renames and content changes, file renames and content changes) are
detected is discussed briefly before the REFERENCE(Troubleshooting,
-Troubleshooting) section which concludes the chapter.
+Troubleshooting) section concludes the chapter.
The AFS process
~~~~~~~~~~~~~~~
para_client setatt test- /path/to/the/audio/file
Instead of a path you may use a shell wildcard pattern. The attribute
-is applied to all audio files matching that pattern:
+is applied to all audio files matching this pattern:
para_client setatt test+ '/test/directory/*'
Note that the images and lyrics are not interpreted at all, and also
the playlist and the mood blobs are only investigated when the mood
-or playlist is activated by using the select command.
+or playlist is activated with the select command.
*The score table*
last_played and the num_played fields in the audio file table.
The score table is recomputed by the select command which loads a
-new mood or playlist.
+mood or playlist. Audio files are chosen for streaming from the rows
+of the score table on a highest-score-first basis.
+
Playlists and moods
~~~~~~~~~~~~~~~~~~~
audio file table. As an example, a mood can define a filename pattern,
which is then matched against the names of audio files in the table.
-Selecting a mood or playlist means the generation of a ranking
-(a score table) for the set of admissible files. Audio files are
-then selected on a highest-score-first basis. The score table is
-recomputed at the moment the mood or playlist is selected.
-
*Playlists*
Playlists are accommodated in the playlist table of the afs database,
-using the aforementioned blob format for tables. A new filelist is
-created using the addpl command, by specifying the full (absolute)
-paths of all desired audio files, separated by newlines. For example
+using the aforementioned blob format for tables. A new playlist is
+created with the addpl command by specifying the full (absolute)
+paths of all desired audio files, separated by newlines. Example:
find /my/mp3/dir -name "*.mp3" | para addpl my_playlist
a set of *mood lines* containing expressions in terms of attributes
and other data contained in the database.
-At any time, at most one mood can be *active* which means that
+At any time at most one mood can be *active* which means that
para_server is going to select only files from that subset of
admissible files.
has no year tag or the content of the year tag is not a number. Such
audio files never match. Another difference is the special treatment
if the year tag is a two-digit number. In this case either 1900 or
-2000 are added to the tag value depending on whether the number is
+2000 is added to the tag value, depending on whether the number is
greater than 2000 plus the current year.
paraslash development. It is necessary for cloning the git repository
and for getting updates.
-ftp://ftp.gnu.org/pub/gnu/gengetopt/ (gengetopt). The C code for
-the command line parsers of all paraslash executables is generated
-by gengetopt. The generated C files are shipped in the tarballs but
-are not contained in the git repository.
-
ftp://ftp.gnu.org/pub/gnu/m4/ (m4). Some input files for gengetopt
are generated from templates by the m4 macro processor.
"git log next"). You should be able to safely build on top of them.
However, at times "next" will be rebuilt from the tip of "master" to
-get rid of merge commits that will never be in "master. The commit
+get rid of merge commits that will never be in "master". The commit
that replaces "next" will usually have the identical tree, but it
will have different ancestry from the tip of "master".
projects / paraslash.git / blobdiff