Changeset 56644 in vbox

Timestamp:

Jun 25, 2015 8:35:23 PM (9 years ago)

Author:

vboxsync

Message:

Audio/ALSA: Fix possible endless loop if the mixer buffer is already full and the ALSA capture device keeps producing samples (null capture device). Check how much we can write to the mixer buffer upfront to avoid loosing any samples

File:

• trunk/src/VBox/Devices/Audio/DrvHostALSAAudio.cpp (modified) (2 diffs)

trunk/src/VBox/Devices/Audio/DrvHostALSAAudio.cpp

@@ -825 +825 @@
     }
 
+    /*
+     * Check how much we can read from the capture device without overflowing
+     * the mixer buffer.
+     */
     Assert(cAvail);
-    size_t cbToRead = AUDIOMIXBUF_S2B(&pHstStrmIn->MixBuf, cAvail);
+    size_t cbToRead = RT_MIN(AUDIOMIXBUF_S2B(&pHstStrmIn->MixBuf, cAvail),
+                             AudioMixBufFreeBytes(&pHstStrmIn->MixBuf));
 
     LogFlowFunc(("cbToRead=%zu, cAvail=%RI32\n", cbToRead, cAvail));
@@ -886 +891 @@
                 break;
 
+            /*
+             * We should not run into a full mixer buffer or we loose samples and
+             * run into an endless loop if ALSA keeps producing samples ("null"
+             * capture device for example).
+             */
+            AssertLogRelMsgBreakStmt(cWritten > 0, ("Mixer buffer shouldn't be full at this point!\n"),
+                                     rc = VERR_INTERNAL_ERROR);
             uint32_t cbWritten = AUDIOMIXBUF_S2B(&pHstStrmIn->MixBuf, cWritten);