libbinder: support BR_ONEWAY_SPAM_SUSPECT

This command tells userspace to dump current stack, which happened
when oneway spamming is detected in kernel. And also add an ioctl
command BINDER_ENABLE_ONEWAY_SPAM_DETECTION to enable/disable this
feature per-proc.

Bug: 181190340
Change-Id: I7afb1df46a4fbf59bc69b56649aa3ee779dfea5a

1 files changed, 15 insertions, 0 deletions

diff --git a/libs/binder/ProcessState.cpp b/libs/binder/ProcessState.cpp
index a8b2fb2ff8..ca99042342 100644
--- a/libs/binder/ProcessState.cpp
+++ b/libs/binder/ProcessState.cpp
@@ -43,6 +43,7 @@
 
 #define BINDER_VM_SIZE ((1 * 1024 * 1024) - sysconf(_SC_PAGE_SIZE) * 2)
 #define DEFAULT_MAX_BINDER_THREADS 15
+#define DEFAULT_ENABLE_ONEWAY_SPAM_DETECTION 1
 
 #ifdef __ANDROID_VNDK__
 const char* kDefaultDriver = "/dev/vndbinder";
@@ -358,6 +359,15 @@ status_t ProcessState::setThreadPoolMaxThreadCount(size_t maxThreads) {
     return result;
 }
 
+status_t ProcessState::enableOnewaySpamDetection(bool enable) {
+    uint32_t enableDetection = enable ? 1 : 0;
+    if (ioctl(mDriverFD, BINDER_ENABLE_ONEWAY_SPAM_DETECTION, &enableDetection) == -1) {
+        ALOGE("Binder ioctl to enable oneway spam detection failed: %s", strerror(errno));
+        return -errno;
+    }
+    return NO_ERROR;
+}
+
 void ProcessState::giveThreadPoolName() {
     androidSetThreadName( makeBinderThreadName().string() );
 }
@@ -388,6 +398,11 @@ static int open_driver(const char *driver)
         if (result == -1) {
             ALOGE("Binder ioctl to set max threads failed: %s", strerror(errno));
         }
+        uint32_t enable = DEFAULT_ENABLE_ONEWAY_SPAM_DETECTION;
+        result = ioctl(fd, BINDER_ENABLE_ONEWAY_SPAM_DETECTION, &enable);
+        if (result == -1) {
+            ALOGE("Binder ioctl to enable oneway spam detection failed: %s", strerror(errno));
+        }
     } else {
         ALOGW("Opening '%s' failed: %s\n", driver, strerror(errno));
     }