git-svn-id: https://svn.musicpd.org/mpd/trunk@7218 09075e82-0dd4-0310-85a5-a0d7c8717e4f

* move set_nonblock{,ing}() into utils.c since we use it
elsewhere, too
* add proper error checking to set_nonblocking()
* use os_compat.h instead of individually #includ-ing system headers

git-svn-id: https://svn.musicpd.org/mpd/trunk@7217 09075e82-0dd4-0310-85a5-a0d7c8717e4f

When the decoder receives SIGCONT during waitNotify(), the kernel
restarts the read() system call.  This lets the decoder process block
indefinitely, while the player process waits for it to react.  This
should probably be solved with a proper signal handler which aborts
the read() system call, but for now, we just write to the pipe to make
it wake up.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7216 09075e82-0dd4-0310-85a5-a0d7c8717e4f

When the decoder process is faster than the player process, all
decodedd buffers are full at some point in time.  The decoder has to
wait for buffers to become free (finished playing).  It used to do
this by polling the buffer status 100 times a second.

This generates a lot of unnecessary CPU wakeups.  This patch adds a
way for the player process to notify the decoder process that it may
continue its work.

We could use pthread_cond for that, unfortunately inter-process
mutexes/conds are not supported by some kernels (Linux), so we cannot
use this light-weight method until mpd moves to using threads instead
of processes.  The other method would be semaphores, which
historically are global resources with a unique name; this historic
API is cumbersome, and I wanted to avoid it.

I came up with a quite naive solution for now: I create an anonymous
pipe with pipe(), and the decoder process reads on that pipe.  Until
the player process sends data on it as a signal, the decoder process
blocks.

This can be optimized in a number of ways:

- if the decoder process is still working (instead of waiting for
buffers), we could save the write() system call, since there is
nobody waiting for the notification.
[ew: I tried this using a counter in shared memory, didn't help]

- the pipe buffer will be full at some point, when the decoder thread
is too slow.  For this reason, the writer side of the pipe is
non-blocking, and mpd can ignore the resulting EWOULDBLOCK.

- since we have shared memory, we could check whether somebody is
actually waiting without a context switch, and we could just not
write the notification byte.
[ew: tried same method/result as first point above]

- if there is already a notification in the pipe, we could also not
write another one.
[ew: tried same method/result as first/third points above]

- the decoder will only consume 64 bytes at a time.  If the pipe
buffer is full, this will result in a lot of read() invocations.
This does not hurt badly, but on a heavily loaded system, this might
add a little bit more load.  The preceding optimizations however
are able eliminate the this.

- finally, we should use another method for inter process
notifications - maybe kill() or just make mpd use threads, finally.

In spite of all these possibilities to optimize this code further,
this pipe notification trick is faster than the 100 Hz poll.  On my
machine, it reduced the number of wakeups to less than 30%.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7215 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Use unsigned variables for storing the count of items or for iteration
variables.  Since there can never be a negative number of items, it
makes sense to use an unsigned data type here.  This change is safe
because the unsigned values are only used for adddressing array items.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7214 09075e82-0dd4-0310-85a5-a0d7c8717e4f

The interfaces main loop repeats the select() (non-blocking) after an
event was handled.  I do not see any reason for that, since all events
should be handled after the first select().  This double select() does
nothing than consume more CPU cycles.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7213 09075e82-0dd4-0310-85a5-a0d7c8717e4f

mpd sets a 1s select() timeout for no reason.  This makes mpd wake up
the CPU, consume some cycles just to see there is nothing to do.  We
can save that by specifying NULL instead of a timeout.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7212 09075e82-0dd4-0310-85a5-a0d7c8717e4f

* malloc() => xmalloc() for error checking
* strncpy() replaced with memcpy(),
memcpy appears perfectly safe here and mpd
does not ever use strncpy() (see r4491)

git-svn-id: https://svn.musicpd.org/mpd/trunk@7211 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This patch does the following:
-enables WVC support for streams as well,
-improves MPD inputStream <=> WavPack stream connector,
-fixes two compile warnings (which were caused by MPD API change).

Mantis #1660 <http://musicpd.org/mantis/view.php?id=1660>

git-svn-id: https://svn.musicpd.org/mpd/trunk@7210 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Basically, I don't trust myself nor Max to not have bugs in our
code when switching over to unsigned types, so I've added more
assertions which will hopefully trip and force us to fix these
bugs before somebody can exploit them :)

Some cleanups for parameter parsing using strtol
and error reporting to the user.  Also, fix some completely
garbled indentation in inputStream_http.c

git-svn-id: https://svn.musicpd.org/mpd/trunk@7209 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@7208 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Terminals are 80 columns and that's a hard limit, no exceptions

git-svn-id: https://svn.musicpd.org/mpd/trunk@7207 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This patch moves code which initializes the OutputBuffer struct to
outputBuffer.c.  Although this is generally a good idea, it prepares
the following patch.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7206 09075e82-0dd4-0310-85a5-a0d7c8717e4f

When dealing with in-memory lengths, the standard type "size_t" should
be used.  Missing one can be quite dangerous, because an attacker
could provoke an integer under-/overflow, which may provide an attack
vector.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7205 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Just one more assertion.  There should be more of that!

git-svn-id: https://svn.musicpd.org/mpd/trunk@7204 09075e82-0dd4-0310-85a5-a0d7c8717e4f

we do not save anything by limiting a variable to an unsigned char,
since the compiler aligns it at machine word size anyway.  however by
using the full machine word, we save one instruction, and we remove
the useless artificial limitation to 255.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7203 09075e82-0dd4-0310-85a5-a0d7c8717e4f

The local variable eof can actually be replaced with a simple "break".
With a negative ret, the value of chunkpos can be invalidated, I am
not sure if this might have been a bug.

[ew: no, a negative ret will correspond to ret == OV_HOLE and ret
will be reset to zero leaving chunkpos untouched (code cleaned up
to make this more obvious]

git-svn-id: https://svn.musicpd.org/mpd/trunk@7202 09075e82-0dd4-0310-85a5-a0d7c8717e4f

The database parser does not check whether the song object has been
initialized yet, which may lead to a NULL pointer dereference.  Add
this check.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7201 09075e82-0dd4-0310-85a5-a0d7c8717e4f

strtok() may return NULL if the input is an empty string.  The
playlist parser did not check for that.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7200 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Local variables which are never read before the first assignment don't
need initialization.  Saves a few bytes of text.  Also don't reset
variables which are never read until function return.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7199 09075e82-0dd4-0310-85a5-a0d7c8717e4f

When we expect an integer as result, why would we use the double
precision floating point parser?  strtol() is a better match, although
we should probably check for overflows...

git-svn-id: https://svn.musicpd.org/mpd/trunk@7198 09075e82-0dd4-0310-85a5-a0d7c8717e4f

There is unreachable code at several positions, e.g. after an
#if/#end, or after an endless loop.  Remove that.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7197 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Tools like "sparse" check for missing downcasts, since implicit cast
may be dangerous.  Although that does not change the compiler result,
it may make the code more readable (IMHO), because you always see when
there may be data cut off.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7196 09075e82-0dd4-0310-85a5-a0d7c8717e4f

The while() loop only checks for interrupted system calls (which woudl
never happen if the signal mask were set up properly), but nobody
checks if the fopen() actually succeeds.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7195 09075e82-0dd4-0310-85a5-a0d7c8717e4f

Although it may not happen in mpd code, it is perfectly possible for a
newly allocated file descriptor to be zero.  For theoretical
correctness, allow 0.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7194 09075e82-0dd4-0310-85a5-a0d7c8717e4f

For code unification: for me, it looks ugly to do a break in the
command in a while() block.  This belongs into the while condition.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7193 09075e82-0dd4-0310-85a5-a0d7c8717e4f

From <http://wiki.xiph.org/index.php/MIME_Types_and_File_Extensions>:
> .oga - audio/ogg
>
>    * Ogg Audio Profile (audio in Ogg container)
>    * Applications supporting .oga, .ogv SHOULD support decoding
>      from muxed Ogg streams
>    * Covers Ogg FLAC, Ghost, and OggPCM
>    * Although they share the same MIME type, Vorbis and Speex
>      use different file extensions.
>    * SHOULD contain a Skeleton logical bitstream.
>    * Vorbis and Speex may use .oga, but it is not the
>      prefered(sic) method of distributing these files because of
>      backwards-compatibility issues.

Thanks to Qball and Rasi for the patch.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7191 09075e82-0dd4-0310-85a5-a0d7c8717e4f

ChangeLog and TODO have been updated to reflect "addid"
improvement.

esd support has been removed from the TODO, PulseAudio
supercedes esd and we already have a PulseAudio output.

Moving NAS, SUN, OSX mixer/output off into the unknown because
nobody seems to use them or care enough to implement them (I
sure don't).

git-svn-id: https://svn.musicpd.org/mpd/trunk@7187 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@7182 09075e82-0dd4-0310-85a5-a0d7c8717e4f

We need to ensure we're working with signed types when assigning
them.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7181 09075e82-0dd4-0310-85a5-a0d7c8717e4f

[ew: cleaned up the dirty union hack a bit]
Signed-off-by: Eric Wong <normalperson@yhbt.net>

git-svn-id: https://svn.musicpd.org/mpd/trunk@7180 09075e82-0dd4-0310-85a5-a0d7c8717e4f

There are still other ways to run the mpd server out of disk-space,
so permissions are still recommended to protect against malicious
users.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7179 09075e82-0dd4-0310-85a5-a0d7c8717e4f

If we keep processing expired interfaces in a loop,
we'll eventually close it and get fd < 0, causing
assertions to fail.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7168 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@7167 09075e82-0dd4-0310-85a5-a0d7c8717e4f

git-svn-id: https://svn.musicpd.org/mpd/trunk@7166 09075e82-0dd4-0310-85a5-a0d7c8717e4f

It's too ugly and broken (both technically and usability-wise)
to be worth supporting in any stable release.

In one sentence: The queue is a very crippled version of the
playlist that takes precedence over the normal playlist.

How is it crippled?

* The "queueid" command only allows the queuing of songs
ALREADY IN THE PLAYLIST!  This promotes having the entire mpd
database of songs in the playlist, which is a stupid practice
to begin with.

* It doesn't allow for meaningful rearranging and movement
of songs within the queue.  To move a song, you'd need to
dequeue and requeue it (and other songs on the list).
Why?  The playlist already allows _all_ these features
and shows everything a client needs to know about the ordering
of songs in a _single_ command!

* Random was a stupid idea to begin with and unfortunately
we're stuck supporting it since we've always had it.  Users
should learn to use "shuffle" instead and not look at their
playlists.  Implementing queue because we have the problem of
random is just a bandage fix and digging ourselves a new hole.

This protocol addition was never in a stable release of mpd, so
reverting it will only break things for people following trunk;
which I'm not too worried about.  I am however worried about
long-term support of this misfeature, so I'm removing it.

Additionally, there are other points:

* It's trivially DoS-able:

(while true; do echo queueid $song_id; done) | nc $MPD_HOST $MPD_PORT

The above commands would cause the queue to become infinitely
expanding, taking up all available memory in the system.  The
mpd playlist was implemented as an array with a fixed (but
configurable) size limit for this reason.

* It's not backwards-compatible.  All clients would require
upgrades (and additional complexity) to even know what the
next song in the playlist is.  mpd is a shared architecture,
and we should not violate the principle of least astonishment
here.

This removes the following commands:
queueid, dequeue, queueinfo

Additionally, the status field of "playlistqueue: " is removed
from the status command.

While this DoS is trivial to fix, the design is simply too
broken to ever support in a real release.

The overloading of the "addid" command and the allowing of
negative numbers to be used as offsets is far more flexible.

This improved "addid" is completely backwards-compatible with
all clients, and does not require clients to have UI changes or
run additional commands to display the queue.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7155 09075e82-0dd4-0310-85a5-a0d7c8717e4f

While mpd has always protected against the infinite expansion of
the main playlist by limiting its size in memory, however the
new storedPlaylist code has never checked for this limit.

Malicious (or clumsy) users could repeatedly append songs to
stored playlists, causing files to grow increasingly large
on disk.  Attempting to load extremely large files into memory
will require mpd to slurp that all into memory, and ultimately
the file would be unusable by mpd because of the configurable
playlist size limit.

Now we limit stored playlists to the max_playlist_length
configuration variable set by the user (default is 16384).  We
will refuse to append to playlist files if they hit that limit;
and also refuse to load more than the specified amount of songs
into memory.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7154 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This disables moving the bonkered moving of the current song to
a (negative) offset of itself (introduced in the last commit).

This also short circuits no-op moves when (from == to) and
avoid needless increasing of the playlist version and causes
clients to issue pointless no-op plchanges commands.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7153 09075e82-0dd4-0310-85a5-a0d7c8717e4f

If (and only if) there is a current song in the playlist,
(player could be stopped), allow the move destination
argument to be specified as a negative number.

This means moving any song (besides the current one) to the -1
position will allow it to be moved to the next song in the
playlist.  Moving any song to position -2 will move it
to the song after the next, and so forth.

Moving a song to -playlist.length will move it to the song
_before_ the current song on the playlist; so this will
work for repeating playlists, too.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7152 09075e82-0dd4-0310-85a5-a0d7c8717e4f

This will allow "addid \"song_url\" <pos>" to atomically insert a
song at any given playlist position.

If the add succeeds, but the actual movement fails (due to
invalid position), then the song_id will be deleted before
the command returns back to the client, and the client
will get an error response.

git-svn-id: https://svn.musicpd.org/mpd/trunk@7151 09075e82-0dd4-0310-85a5-a0d7c8717e4f