liblog: print message payload of zero length
logcat will crash if the log message payload is of zero length. Side
effect of possible log messages from LogKlog in eng and userdebug
builds, or lower level logging calls.
NB: The referenced bug cited an example of this native crash, this
does not fix the problem cited in the bug about the
com.android.music shutdown.
Bug: 25774695
Change-Id: I5c7a6ad8db640ba9bc8d34fab04ba7cc2a9a426a
diff --git a/liblog/logprint.c b/liblog/logprint.c
index ad52a81..40e13f4 100644
--- a/liblog/logprint.c
+++ b/liblog/logprint.c
@@ -500,14 +500,14 @@
}
if (msgEnd == -1) {
/* incoming message not null-terminated; force it */
- msgEnd = buf->len - 1;
+ msgEnd = buf->len - 1; /* may result in msgEnd < msgStart */
msg[msgEnd] = '\0';
}
entry->priority = msg[0];
entry->tag = msg + 1;
entry->message = msg + msgStart;
- entry->messageLen = msgEnd - msgStart;
+ entry->messageLen = (msgEnd < msgStart) ? 0 : (msgEnd - msgStart);
return 0;
}