Merge changes from topic "libprocessgroup_rc"

* changes:
  CgroupSetupCgroups -> CgroupSetup
  Add libcgrouprc to ld.config.*.txt.
  libprocessgroup: use libcgrouprc to read cgroup.rc
  libprocessgroup_setup: use libcgrouprc_format
  libprocessgroup: Move CgroupSetupCgroups() to libprocessgroup_setup
  libprocessgroup: Add libcgrouprc
  libprocessgroup: Add libcgrouprc_format

1 files changed, 106 insertions, 0 deletions

diff --git a/libprocessgroup/cgrouprc/cgroup_file.cpp b/libprocessgroup/cgrouprc/cgroup_file.cpp
new file mode 100644
index 000000000..e26d84114
--- /dev/null
+++ b/libprocessgroup/cgrouprc/cgroup_file.cpp
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+#include <memory>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <android/cgrouprc.h>
+#include <processgroup/processgroup.h>
+
+#include "cgrouprc_internal.h"
+
+using android::base::StringPrintf;
+using android::base::unique_fd;
+
+using android::cgrouprc::format::CgroupController;
+using android::cgrouprc::format::CgroupFile;
+
+static CgroupFile* LoadRcFile() {
+    struct stat sb;
+
+    unique_fd fd(TEMP_FAILURE_RETRY(open(CGROUPS_RC_PATH, O_RDONLY | O_CLOEXEC)));
+    if (fd < 0) {
+        PLOG(ERROR) << "open() failed for " << CGROUPS_RC_PATH;
+        return nullptr;
+    }
+
+    if (fstat(fd, &sb) < 0) {
+        PLOG(ERROR) << "fstat() failed for " << CGROUPS_RC_PATH;
+        return nullptr;
+    }
+
+    size_t file_size = sb.st_size;
+    if (file_size < sizeof(CgroupFile)) {
+        LOG(ERROR) << "Invalid file format " << CGROUPS_RC_PATH;
+        return nullptr;
+    }
+
+    CgroupFile* file_data = (CgroupFile*)mmap(nullptr, file_size, PROT_READ, MAP_SHARED, fd, 0);
+    if (file_data == MAP_FAILED) {
+        PLOG(ERROR) << "Failed to mmap " << CGROUPS_RC_PATH;
+        return nullptr;
+    }
+
+    if (file_data->version_ != CgroupFile::FILE_CURR_VERSION) {
+        LOG(ERROR) << CGROUPS_RC_PATH << " file version mismatch";
+        munmap(file_data, file_size);
+        return nullptr;
+    }
+
+    auto expected = sizeof(CgroupFile) + file_data->controller_count_ * sizeof(CgroupController);
+    if (file_size != expected) {
+        LOG(ERROR) << CGROUPS_RC_PATH << " file has invalid size, expected " << expected
+                   << ", actual " << file_size;
+        munmap(file_data, file_size);
+        return nullptr;
+    }
+
+    return file_data;
+}
+
+static CgroupFile* GetInstance() {
+    // Deliberately leak this object (not munmap) to avoid a race between destruction on
+    // process exit and concurrent access from another thread.
+    static auto* file = LoadRcFile();
+    return file;
+}
+
+uint32_t ACgroupFile_getVersion() {
+    auto file = GetInstance();
+    if (file == nullptr) return 0;
+    return file->version_;
+}
+
+uint32_t ACgroupFile_getControllerCount() {
+    auto file = GetInstance();
+    if (file == nullptr) return 0;
+    return file->controller_count_;
+}
+
+const ACgroupController* ACgroupFile_getController(uint32_t index) {
+    auto file = GetInstance();
+    if (file == nullptr) return nullptr;
+    CHECK(index < file->controller_count_);
+    // Although the object is not actually an ACgroupController object, all ACgroupController_*
+    // functions implicitly convert ACgroupController* back to CgroupController* before invoking
+    // member functions.
+    return static_cast<ACgroupController*>(&file->controllers_[index]);
+}