commit 1e52e63238ec0a034501dc1ba5b42495fa554a38
author Hridya Valsaraju <hridya@google.com> Wed Apr 21 16:30:20 2021 -0700
committer Hridya Valsaraju <hridya@google.com> Thu Apr 22 15:10:46 2021 -0700
tree 1b5d16593cc9282ef664e444e762a9d109a2fd92
parent 91ce32adb93003d915bc17d06ba8370165bb053e

Let the default Atrace HAL support /sys/kernel/tracing

With this change, atrace HAL will look for tracefs in
/sys/kernel/tracing first and /sys/kernel/debug/tracing second.

Test: systrace
Bug: 185427606
Change-Id: Iccc5af92db222dc422a527c14b1f2fb7bc4e7746

atrace/1.0/default/AtraceDevice.cpp

diff --git a/atrace/1.0/default/AtraceDevice.cpp b/atrace/1.0/default/AtraceDevice.cpp
index 4e82b0a..9f0c4c4 100644
--- a/atrace/1.0/default/AtraceDevice.cpp
+++ b/atrace/1.0/default/AtraceDevice.cpp
@@ -16,6 +16,7 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/stringprintf.h>
 
 #include "AtraceDevice.h"
 
@@ -39,15 +40,11 @@
         // gfx
         {
                 "gfx",
-                {"Graphics",
-                 {{"/sys/kernel/debug/tracing/events/mdss/enable", false},
-                  {"/sys/kernel/debug/tracing/events/sde/enable", false},
-                  {"/sys/kernel/debug/tracing/events/mali_systrace/enable", false}}},
+                {"Graphics", {{"mdss", false}, {"sde", false}, {"mali_systrace", false}}},
         },
         {
                 "ion",
-                {"ION allocation",
-                 {{"/sys/kernel/debug/tracing/events/kmem/ion_alloc_buffer_start/enable", false}}},
+                {"ION allocation", {{"kmem/ion_alloc_buffer_start", false}}},
         },
 };
 
@@ -65,16 +62,31 @@
     return Void();
 }
 
+AtraceDevice::AtraceDevice() {
+    struct stat st;
+
+    tracefs_event_root_ = "/sys/kernel/tracing/events/";
+    if (stat(tracefs_event_root_.c_str(), &st) != 0) {
+        tracefs_event_root_ = "/sys/kernel/debug/tracing/events/";
+        CHECK(stat(tracefs_event_root_.c_str(), &st) == 0) << "tracefs must be mounted at either"
+                                                              "/sys/kernel/tracing or "
+                                                              "/sys/kernel/debug/tracing";
+    }
+}
+
 Return<::android::hardware::atrace::V1_0::Status> AtraceDevice::enableCategories(
-    const hidl_vec<hidl_string>& categories) {
+        const hidl_vec<hidl_string>& categories) {
     if (!categories.size()) {
         return Status::ERROR_INVALID_ARGUMENT;
     }
+
     for (auto& c : categories) {
         if (kTracingMap.count(c)) {
             for (auto& p : kTracingMap.at(c).paths) {
-                if (!android::base::WriteStringToFile("1", p.first)) {
-                    LOG(ERROR) << "Failed to enable tracing on: " << p.first;
+                std::string tracefs_event_enable_path = android::base::StringPrintf(
+                        "%s%s/enable", tracefs_event_root_.c_str(), p.first.c_str());
+                if (!android::base::WriteStringToFile("1", tracefs_event_enable_path)) {
+                    LOG(ERROR) << "Failed to enable tracing on: " << tracefs_event_enable_path;
                     if (p.second) {
                         // disable before return
                         disableAllCategories();
@@ -91,10 +103,13 @@
 
 Return<::android::hardware::atrace::V1_0::Status> AtraceDevice::disableAllCategories() {
     auto ret = Status::SUCCESS;
+
     for (auto& c : kTracingMap) {
         for (auto& p : c.second.paths) {
-            if (!android::base::WriteStringToFile("0", p.first)) {
-                LOG(ERROR) << "Failed to disable tracing on: " << p.first;
+            std::string tracefs_event_enable_path = android::base::StringPrintf(
+                    "%s%s/enable", tracefs_event_root_.c_str(), p.first.c_str());
+            if (!android::base::WriteStringToFile("0", tracefs_event_enable_path)) {
+                LOG(ERROR) << "Failed to disable tracing on: " << tracefs_event_enable_path;
                 if (p.second) {
                     ret = Status::ERROR_TRACING_POINT;
                 }