dumpstate: attach more than 1 trace to BR

perfetto now allows stopping multiple ongoing traces by using
`--save-all-for-bugreport`. This change serializes all the
traces, not just the main one, in the BR.

Bug: 321196572
Flag: perfetto.flags.save_all_traces_in_bugreport
Test: atest dumpstate_smoke_test  -- --test-arg com.android.tradefed.testtype.GTest:native-test-flag:"--gtest_filter=DumpstateTracingTest*"

Change-Id: Ibf6e2c7d9620f49cd50a49716586b9b29c94e6a7
diff --git a/cmds/dumpstate/dumpstate.cpp b/cmds/dumpstate/dumpstate.cpp
index 888fb67..9e3e2b0 100644
--- a/cmds/dumpstate/dumpstate.cpp
+++ b/cmds/dumpstate/dumpstate.cpp
@@ -57,6 +57,7 @@
 #include <log/log_read.h>
 #include <math.h>
 #include <openssl/sha.h>
+#include <perfetto_flags.h>
 #include <poll.h>
 #include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
@@ -190,7 +191,7 @@
 #define SNAPSHOTCTL_LOG_DIR "/data/misc/snapshotctl_log"
 #define LINKERCONFIG_DIR "/linkerconfig"
 #define PACKAGE_DEX_USE_LIST "/data/system/package-dex-usage.list"
-#define SYSTEM_TRACE_SNAPSHOT "/data/misc/perfetto-traces/bugreport/systrace.pftrace"
+#define SYSTEM_TRACE_DIR "/data/misc/perfetto-traces/bugreport"
 #define CGROUPFS_DIR "/sys/fs/cgroup"
 #define SDK_EXT_INFO "/apex/com.android.sdkext/bin/derive_sdk"
 #define DROPBOX_DIR "/data/system/dropbox"
@@ -359,6 +360,31 @@
     return CopyFileToFd(input_file, out_fd.get());
 }
 
+template <typename Func>
+size_t ForEachTrace(Func func) {
+    std::unique_ptr<DIR, decltype(&closedir)> traces_dir(opendir(SYSTEM_TRACE_DIR), closedir);
+
+    if (traces_dir == nullptr) {
+        MYLOGW("Unable to open directory %s: %s\n", SYSTEM_TRACE_DIR, strerror(errno));
+        return 0;
+    }
+
+    size_t traces_found = 0;
+    struct dirent* entry = nullptr;
+    while ((entry = readdir(traces_dir.get()))) {
+        if (entry->d_type != DT_REG) {
+            continue;
+        }
+        std::string trace_path = std::string(SYSTEM_TRACE_DIR) + "/" + entry->d_name;
+        if (access(trace_path.c_str(), F_OK) != 0) {
+            continue;
+        }
+        ++traces_found;
+        func(trace_path);
+    }
+    return traces_found;
+}
+
 }  // namespace
 }  // namespace os
 }  // namespace android
@@ -1101,20 +1127,16 @@
     // This function copies into the .zip the system trace that was snapshotted
     // by the early call to MaybeSnapshotSystemTraceAsync(), if any background
     // tracing was happening.
-    bool system_trace_exists = access(SYSTEM_TRACE_SNAPSHOT, F_OK) == 0;
-    if (!system_trace_exists) {
-        // No background trace was happening at the time MaybeSnapshotSystemTraceAsync() was invoked
-        if (!PropertiesHelper::IsUserBuild()) {
-            MYLOGI(
-                "No system traces found. Check for previously uploaded traces by looking for "
-                "go/trace-uuid in logcat")
-        }
-        return;
+    size_t traces_found = android::os::ForEachTrace([&](const std::string& trace_path) {
+        ds.AddZipEntry(ZIP_ROOT_DIR + trace_path, trace_path);
+        android::os::UnlinkAndLogOnError(trace_path);
+    });
+
+    if (traces_found == 0 && !PropertiesHelper::IsUserBuild()) {
+        MYLOGI(
+            "No system traces found. Check for previously uploaded traces by looking for "
+            "go/trace-uuid in logcat")
     }
-    ds.AddZipEntry(
-            ZIP_ROOT_DIR + SYSTEM_TRACE_SNAPSHOT,
-            SYSTEM_TRACE_SNAPSHOT);
-    android::os::UnlinkAndLogOnError(SYSTEM_TRACE_SNAPSHOT);
 }
 
 static void DumpVisibleWindowViews() {
@@ -3412,8 +3434,8 @@
     // duration is logged into MYLOG instead.
     PrintHeader();
 
-    bool system_trace_exists = access(SYSTEM_TRACE_SNAPSHOT, F_OK) == 0;
-    if (options_->use_predumped_ui_data && !system_trace_exists) {
+    size_t trace_count = android::os::ForEachTrace([](const std::string&) {});
+    if (options_->use_predumped_ui_data && trace_count == 0) {
         MYLOGW("Ignoring 'use predumped data' flag because no predumped data is available");
         options_->use_predumped_ui_data = false;
     }
@@ -3560,20 +3582,24 @@
     }
 
     // If a stale file exists already, remove it.
-    unlink(SYSTEM_TRACE_SNAPSHOT);
+    android::os::ForEachTrace([&](const std::string& trace_path) { unlink(trace_path.c_str()); });
 
     MYLOGI("Launching async '%s'", SERIALIZE_PERFETTO_TRACE_TASK.c_str())
+
     return std::async(
         std::launch::async, [this, outPath = std::move(outPath), outFd = std::move(outFd)] {
-            // If a background system trace is happening and is marked as "suitable for
-            // bugreport" (i.e. bugreport_score > 0 in the trace config), this command
-            // will stop it and serialize into SYSTEM_TRACE_SNAPSHOT. In the (likely)
-            // case that no trace is ongoing, this command is a no-op.
+            // If one or more background system traces are happening and are marked as
+            // "suitable for bugreport" (bugreport_score > 0 in the trace config), this command
+            // will snapshot them into SYSTEM_TRACE_DIR.
+            // In the (likely) case that no trace is ongoing, this command is a no-op.
             // Note: this should not be enqueued as we need to freeze the trace before
             // dumpstate starts. Otherwise the trace ring buffers will contain mostly
             // the dumpstate's own activity which is irrelevant.
+            const char* cmd_arg = perfetto::flags::save_all_traces_in_bugreport()
+                                      ? "--save-all-for-bugreport"
+                                      : "--save-for-bugreport";
             RunCommand(
-                SERIALIZE_PERFETTO_TRACE_TASK, {"perfetto", "--save-for-bugreport"},
+                SERIALIZE_PERFETTO_TRACE_TASK, {"perfetto", cmd_arg},
                 CommandOptions::WithTimeout(30).DropRoot().CloseAllFileDescriptorsOnExec().Build(),
                 false, outFd);
             // MaybeAddSystemTraceToZip() will take care of copying the trace in the zip