diff options
author | Tanu Kaskinen <tanu.kaskinen@digia.com> | 2011-02-24 16:16:43 +0200 |
---|---|---|
committer | Colin Guthrie <cguthrie@mandriva.org> | 2011-02-26 10:40:06 +0000 |
commit | 6bd34156b130c07b130de10111a12ef6dab18b52 (patch) | |
tree | 08d635f07c2165c669eed2bfcd1310babed74e38 /src/modules | |
parent | b3644c1bcd5f5d73fd2dc7b898e66b11ca3ad588 (diff) |
virtual-sink: Fix a crash when moving the sink to a new master right after setup.
If the virtual sink is moved to a new master right after it has been created,
then the virtual sink input's memblockq can be rewound to a negative read
index. The data written prior to the move starts from index zero, so after the
rewind there's a bit of silence. If the memblockq doesn't have a silence
memchunk set, then pa_memblockq_peek() will return zero in such case, and the
returned memchunk's memblock pointer will be NULL.
That scenario wasn't taken into account in the implementation of
sink_input_pop_cb. Setting a silence memchunk for the memblockq solves this
problem, because pa_memblock_peek() will now return a valid memblock if the
read index happens to point to a hole in the memblockq.
I believe this isn't the best possible solution, though. It doesn't really make
sense to rewind the sink input's memblockq beyond index 0 in the first place,
because now when the stream starts to play to the new master sink, there's some
unnecessary silence before the actual data starts. This is a small problem,
though, and I don't grok the rewinding system well enough to know how to fix
this issue properly.
I went through all files that call pa_memblockq_peek() to see if there are more
similar bugs. play-memblockq.c was the only one that looked to me like it might
be broken in the same way. I didn't try reproducing the bug with
play-memblockq.c, though, so I just added a FIXME comment there.
Diffstat (limited to 'src/modules')
-rw-r--r-- | src/modules/module-virtual-sink.c | 10 | ||||
-rw-r--r-- | src/modules/rtp/rtp.h | 3 |
2 files changed, 8 insertions, 5 deletions
diff --git a/src/modules/module-virtual-sink.c b/src/modules/module-virtual-sink.c index bad159ce..58ea932d 100644 --- a/src/modules/module-virtual-sink.c +++ b/src/modules/module-virtual-sink.c @@ -483,6 +483,7 @@ int pa__init(pa_module*m) { pa_sink_new_data sink_data; pa_bool_t use_volume_sharing = FALSE; pa_bool_t force_flat_volume = FALSE; + pa_memchunk silence; pa_assert(m); @@ -606,12 +607,11 @@ int pa__init(pa_module*m) { u->sink->input_to_master = u->sink_input; - /* (9) IF YOU REQUIRE A FIXED BLOCK SIZE MAKE SURE TO PASS A - * SILENCE MEMBLOCK AS LAST PARAMETER - * HERE. pa_sink_input_get_silence() IS USEFUL HERE. */ - u->memblockq = pa_memblockq_new(0, MEMBLOCKQ_MAXLENGTH, 0, pa_frame_size(&ss), 1, 1, 0, NULL); + pa_sink_input_get_silence(u->sink_input, &silence); + u->memblockq = pa_memblockq_new(0, MEMBLOCKQ_MAXLENGTH, 0, pa_frame_size(&ss), 1, 1, 0, &silence); + pa_memblock_unref(silence.memblock); - /* (10) INITIALIZE ANYTHING ELSE YOU NEED HERE */ + /* (9) INITIALIZE ANYTHING ELSE YOU NEED HERE */ pa_sink_put(u->sink); pa_sink_input_put(u->sink_input); diff --git a/src/modules/rtp/rtp.h b/src/modules/rtp/rtp.h index b197e82f..e975e750 100644 --- a/src/modules/rtp/rtp.h +++ b/src/modules/rtp/rtp.h @@ -40,6 +40,9 @@ typedef struct pa_rtp_context { } pa_rtp_context; pa_rtp_context* pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint32_t ssrc, uint8_t payload, size_t frame_size); + +/* If the memblockq doesn't have a silence memchunk set, then the caller must + * guarantee that the current read index doesn't point to a hole. */ int pa_rtp_send(pa_rtp_context *c, size_t size, pa_memblockq *q); pa_rtp_context* pa_rtp_context_init_recv(pa_rtp_context *c, int fd, size_t frame_size); |