Adds the gpu_counter_producer command.

This is a small binary that will load a GPU vendor provided shared
library called libgpudataproducer.so, look for the "start" symbol in
that library, and call it. This can be used to start the GPU hardware
counter Perfetto producer that will allow tracing of GPU profiling data
via Perfetto.

See go/gpu-profiling-arch for more details on the GPU profiling
architecture design.

Test: manual
Bug: b/273907878
Change-Id: Iacccb562d0ef154c105de034c8801642cab72532

3 files changed, 187 insertions, 0 deletions

diff --git a/cmds/gpu_counter_producer/Android.bp b/cmds/gpu_counter_producer/Android.bp
new file mode 100644
index 000000000000..5b118ce62679
--- /dev/null
+++ b/cmds/gpu_counter_producer/Android.bp
@@ -0,0 +1,26 @@
+package {
+    // See: http://go/android-license-faq
+    default_applicable_licenses: ["frameworks_base_license"],
+}
+
+cc_binary {
+    name: "gpu_counter_producer",
+
+    srcs: ["main.cpp"],
+
+    shared_libs: [
+        "libdl",
+        "liblog",
+    ],
+
+    cflags: [
+        "-Wall",
+        "-Werror",
+        "-Wunused",
+        "-Wunreachable-code",
+        "-fPIE",
+        "-pie",
+    ],
+
+    soc_specific: true,
+}
diff --git a/cmds/gpu_counter_producer/OWNERS b/cmds/gpu_counter_producer/OWNERS
new file mode 100644
index 000000000000..892c2fb81cde
--- /dev/null
+++ b/cmds/gpu_counter_producer/OWNERS
@@ -0,0 +1 @@
+pmuetschard@google.com
diff --git a/cmds/gpu_counter_producer/main.cpp b/cmds/gpu_counter_producer/main.cpp
new file mode 100644
index 000000000000..1054cba74a6b
--- /dev/null
+++ b/cmds/gpu_counter_producer/main.cpp
@@ -0,0 +1,160 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "gpu_counters"
+
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <log/log.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define _LOG(level, msg, ...)                                 \
+    do {                                                      \
+        fprintf(stderr, #level ": " msg "\n", ##__VA_ARGS__); \
+        ALOG##level(msg, ##__VA_ARGS__);                      \
+    } while (false)
+
+#define LOG_ERR(msg, ...) _LOG(E, msg, ##__VA_ARGS__)
+#define LOG_WARN(msg, ...) _LOG(W, msg, ##__VA_ARGS__)
+#define LOG_INFO(msg, ...) _LOG(I, msg, ##__VA_ARGS__)
+
+#define NELEM(x) (sizeof(x) / sizeof(x[0]))
+
+typedef void (*FN_PTR)(void);
+
+const char* kProducerPaths[] = {
+        "libgpudataproducer.so",
+};
+const char* kPidFileName = "/data/local/tmp/gpu_counter_producer.pid";
+
+static FN_PTR loadLibrary(const char* lib) {
+    char* error;
+
+    LOG_INFO("Trying %s", lib);
+    void* handle = dlopen(lib, RTLD_GLOBAL);
+    if ((error = dlerror()) != nullptr || handle == nullptr) {
+        LOG_WARN("Error loading lib: %s", error);
+        return nullptr;
+    }
+
+    FN_PTR startFunc = (FN_PTR)dlsym(handle, "start");
+    if ((error = dlerror()) != nullptr) {
+        LOG_ERR("Error looking for start symbol: %s", error);
+        dlclose(handle);
+        return nullptr;
+    }
+    return startFunc;
+}
+
+static void killExistingProcess() {
+    int fd = open(kPidFileName, O_RDONLY);
+    if (fd == -1) {
+        return;
+    }
+    char pidString[10];
+    if (read(fd, pidString, 10) > 0) {
+        int pid = -1;
+        sscanf(pidString, "%d", &pid);
+        if (pid > 0) {
+            kill(pid, SIGINT);
+        }
+    }
+    close(fd);
+}
+
+static bool writeToPidFile() {
+    killExistingProcess();
+    int fd = open(kPidFileName, O_CREAT | O_WRONLY | O_TRUNC,
+                  S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
+    if (fd == -1) {
+        return false;
+    }
+    pid_t pid = getpid();
+    char pidString[10];
+    sprintf(pidString, "%d", pid);
+    write(fd, pidString, strlen(pidString));
+    close(fd);
+    return true;
+}
+
+static void clearPidFile() {
+    unlink(kPidFileName);
+}
+
+static void usage(const char* pname) {
+    fprintf(stderr,
+            "Starts the GPU hardware counter profiling Perfetto data producer.\n\n"
+            "usage: %s [-hf]\n"
+            "   -f: run in the foreground.\n"
+            "   -h: this message.\n",
+            pname);
+}
+
+// Program to load the GPU Perfetto producer .so and call start().
+int main(int argc, char** argv) {
+    const char* pname = argv[0];
+    bool foreground = false;
+    int c;
+    while ((c = getopt(argc, argv, "fh")) != -1) {
+        switch (c) {
+            case 'f':
+                foreground = true;
+                break;
+            case '?':
+            case ':':
+            case 'h':
+                usage(pname);
+                return 1;
+        }
+    }
+
+    if (optind < argc) {
+        usage(pname);
+        return 1;
+    }
+
+    if (!foreground) {
+        daemon(0, 0);
+    }
+
+    if (!writeToPidFile()) {
+        LOG_ERR("Could not open %s", kPidFileName);
+        return 1;
+    }
+
+    dlerror(); // Clear any possibly ignored previous error.
+    FN_PTR startFunc = nullptr;
+    for (int i = 0; startFunc == nullptr && i < NELEM(kProducerPaths); i++) {
+        startFunc = loadLibrary(kProducerPaths[i]);
+    }
+
+    if (startFunc == nullptr) {
+        LOG_ERR("Did not find the producer library");
+        LOG_ERR("LD_LIBRARY_PATH=%s", getenv("LD_LIBRARY_PATH"));
+        clearPidFile();
+        return 1;
+    }
+
+    LOG_INFO("Calling start at %p", startFunc);
+    (*startFunc)();
+    LOG_WARN("Producer has exited.");
+
+    clearPidFile();
+    return 0;
+}