Give hostapd a hint that it is about to die

Give hostapd SIGTERM and some time do take itself down
before dropping SIGKILL on it.  This is blocking, and
we'll eventually replace it with an asynchronous interface
but it keeps us healthy for now.

Bug: 30311493
Change-Id: Iadbd3a4fd5c49c42d9bba12f19cfcd65ee567a67
Test: Integration tests finally pass reliably

diff --git a/ap_interface_impl.cpp b/ap_interface_impl.cpp
index 3c80da4..59cb7e8 100644 (file)
--- a/ap_interface_impl.cpp
+++ b/ap_interface_impl.cpp
@@ -16,6 +16,8 @@
 
 #include "wificond/ap_interface_impl.h"
 
+#include <android-base/logging.h>
+
 #include "wificond/ap_interface_binder.h"
 
 using android::net::wifi::IApInterface;
@@ -49,6 +51,24 @@ bool ApInterfaceImpl::StartHostapd() {
 }
 
 bool ApInterfaceImpl::StopHostapd() {
+  pid_t hostapd_pid;
+  if (hostapd_manager_->GetHostapdPid(&hostapd_pid)) {
+    // We do this because it was found that hostapd would leave the driver in a
+    // bad state if init killed it harshly with a SIGKILL. b/30311493
+    if (kill(hostapd_pid, SIGTERM) == -1) {
+      LOG(ERROR) << "Error delivering signal to hostapd: " << strerror(errno);
+    }
+    // This should really be asynchronous: b/30465379
+    for (int tries = 0; tries < 10; tries++) {
+      // Try to give hostapd some time to go down.
+      if (!hostapd_manager_->IsHostapdRunning()) {
+        break;
+      }
+      usleep(10 * 1000);  // Don't busy wait.
+    }
+  }
+
+  // Always drop a SIGKILL on hostapd on the way out, just in case.
   return hostapd_manager_->StopHostapd();
 }