libprocessgroup: Move CgroupSetupCgroups() to libprocessgroup_setup
Only init uses SetupCgroups. This functionality is
moved from libprocessgroup to its own library, and only
init links to it.
Also, merge CgroupSetupCgroups() with CgroupMap::SetupCgroups()
because the former is just an alias of the latter, and
CgroupMap does not belong to libcgrouprc_setup.
Test: boots
Bug: 123664216
Change-Id: I941dc0c415e2b22ae663d43e30dc7a464687325e
Merged-In: I941dc0c415e2b22ae663d43e30dc7a464687325e
diff --git a/libprocessgroup/setup/Android.bp b/libprocessgroup/setup/Android.bp
new file mode 100644
index 0000000..a403a23
--- /dev/null
+++ b/libprocessgroup/setup/Android.bp
@@ -0,0 +1,41 @@
+//
+// 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.
+//
+
+cc_library_shared {
+ name: "libprocessgroup_setup",
+ recovery_available: true,
+ srcs: [
+ "cgroup_map_write.cpp",
+ ],
+ export_include_dirs: [
+ "include",
+ ],
+ shared_libs: [
+ "libbase",
+ "libprocessgroup",
+ "libjsoncpp",
+ ],
+ header_libs: [
+ "libprocessgroup_headers",
+ ],
+ export_header_lib_headers: [
+ "libprocessgroup_headers",
+ ],
+ cflags: [
+ "-Wall",
+ "-Werror",
+ ],
+}
diff --git a/libprocessgroup/setup/cgroup_descriptor.h b/libprocessgroup/setup/cgroup_descriptor.h
new file mode 100644
index 0000000..185c5f9
--- /dev/null
+++ b/libprocessgroup/setup/cgroup_descriptor.h
@@ -0,0 +1,38 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+// TODO(b/123664216): Use libcgrouprc_format
+#include "../cgroup_map.h"
+
+// Complete controller description for mounting cgroups
+class CgroupDescriptor {
+ public:
+ CgroupDescriptor(uint32_t version, const std::string& name, const std::string& path,
+ mode_t mode, const std::string& uid, const std::string& gid);
+
+ const CgroupController* controller() const { return &controller_; }
+ mode_t mode() const { return mode_; }
+ std::string uid() const { return uid_; }
+ std::string gid() const { return gid_; }
+
+ private:
+ CgroupController controller_;
+ mode_t mode_ = 0;
+ std::string uid_;
+ std::string gid_;
+};
diff --git a/libprocessgroup/setup/cgroup_map_write.cpp b/libprocessgroup/setup/cgroup_map_write.cpp
new file mode 100644
index 0000000..8ecc0a4
--- /dev/null
+++ b/libprocessgroup/setup/cgroup_map_write.cpp
@@ -0,0 +1,324 @@
+/*
+ * 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "libprocessgroup"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <grp.h>
+#include <pwd.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <regex>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <json/reader.h>
+#include <json/value.h>
+#include <processgroup/processgroup.h>
+#include <processgroup/setup.h>
+
+#include "cgroup_descriptor.h"
+
+using android::base::GetBoolProperty;
+using android::base::StringPrintf;
+using android::base::unique_fd;
+
+static constexpr const char* CGROUPS_DESC_FILE = "/etc/cgroups.json";
+static constexpr const char* CGROUPS_DESC_VENDOR_FILE = "/vendor/etc/cgroups.json";
+
+static bool Mkdir(const std::string& path, mode_t mode, const std::string& uid,
+ const std::string& gid) {
+ if (mode == 0) {
+ mode = 0755;
+ }
+
+ if (mkdir(path.c_str(), mode) != 0) {
+ /* chmod in case the directory already exists */
+ if (errno == EEXIST) {
+ if (fchmodat(AT_FDCWD, path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
+ // /acct is a special case when the directory already exists
+ // TODO: check if file mode is already what we want instead of using EROFS
+ if (errno != EROFS) {
+ PLOG(ERROR) << "fchmodat() failed for " << path;
+ return false;
+ }
+ }
+ } else {
+ PLOG(ERROR) << "mkdir() failed for " << path;
+ return false;
+ }
+ }
+
+ if (uid.empty()) {
+ return true;
+ }
+
+ passwd* uid_pwd = getpwnam(uid.c_str());
+ if (!uid_pwd) {
+ PLOG(ERROR) << "Unable to decode UID for '" << uid << "'";
+ return false;
+ }
+
+ uid_t pw_uid = uid_pwd->pw_uid;
+ gid_t gr_gid = -1;
+ if (!gid.empty()) {
+ group* gid_pwd = getgrnam(gid.c_str());
+ if (!gid_pwd) {
+ PLOG(ERROR) << "Unable to decode GID for '" << gid << "'";
+ return false;
+ }
+ gr_gid = gid_pwd->gr_gid;
+ }
+
+ if (lchown(path.c_str(), pw_uid, gr_gid) < 0) {
+ PLOG(ERROR) << "lchown() failed for " << path;
+ return false;
+ }
+
+ /* chown may have cleared S_ISUID and S_ISGID, chmod again */
+ if (mode & (S_ISUID | S_ISGID)) {
+ if (fchmodat(AT_FDCWD, path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
+ PLOG(ERROR) << "fchmodat() failed for " << path;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool ReadDescriptorsFromFile(const std::string& file_name,
+ std::map<std::string, CgroupDescriptor>* descriptors) {
+ std::vector<CgroupDescriptor> result;
+ std::string json_doc;
+
+ if (!android::base::ReadFileToString(file_name, &json_doc)) {
+ PLOG(ERROR) << "Failed to read task profiles from " << file_name;
+ return false;
+ }
+
+ Json::Reader reader;
+ Json::Value root;
+ if (!reader.parse(json_doc, root)) {
+ LOG(ERROR) << "Failed to parse cgroups description: " << reader.getFormattedErrorMessages();
+ return false;
+ }
+
+ if (root.isMember("Cgroups")) {
+ const Json::Value& cgroups = root["Cgroups"];
+ for (Json::Value::ArrayIndex i = 0; i < cgroups.size(); ++i) {
+ std::string name = cgroups[i]["Controller"].asString();
+ auto iter = descriptors->find(name);
+ if (iter == descriptors->end()) {
+ descriptors->emplace(
+ name, CgroupDescriptor(
+ 1, name, cgroups[i]["Path"].asString(),
+ std::strtoul(cgroups[i]["Mode"].asString().c_str(), 0, 8),
+ cgroups[i]["UID"].asString(), cgroups[i]["GID"].asString()));
+ } else {
+ iter->second = CgroupDescriptor(
+ 1, name, cgroups[i]["Path"].asString(),
+ std::strtoul(cgroups[i]["Mode"].asString().c_str(), 0, 8),
+ cgroups[i]["UID"].asString(), cgroups[i]["GID"].asString());
+ }
+ }
+ }
+
+ if (root.isMember("Cgroups2")) {
+ const Json::Value& cgroups2 = root["Cgroups2"];
+ auto iter = descriptors->find(CGROUPV2_CONTROLLER_NAME);
+ if (iter == descriptors->end()) {
+ descriptors->emplace(
+ CGROUPV2_CONTROLLER_NAME,
+ CgroupDescriptor(2, CGROUPV2_CONTROLLER_NAME, cgroups2["Path"].asString(),
+ std::strtoul(cgroups2["Mode"].asString().c_str(), 0, 8),
+ cgroups2["UID"].asString(), cgroups2["GID"].asString()));
+ } else {
+ iter->second =
+ CgroupDescriptor(2, CGROUPV2_CONTROLLER_NAME, cgroups2["Path"].asString(),
+ std::strtoul(cgroups2["Mode"].asString().c_str(), 0, 8),
+ cgroups2["UID"].asString(), cgroups2["GID"].asString());
+ }
+ }
+
+ return true;
+}
+
+static bool ReadDescriptors(std::map<std::string, CgroupDescriptor>* descriptors) {
+ // load system cgroup descriptors
+ if (!ReadDescriptorsFromFile(CGROUPS_DESC_FILE, descriptors)) {
+ return false;
+ }
+
+ // load vendor cgroup descriptors if the file exists
+ if (!access(CGROUPS_DESC_VENDOR_FILE, F_OK) &&
+ !ReadDescriptorsFromFile(CGROUPS_DESC_VENDOR_FILE, descriptors)) {
+ return false;
+ }
+
+ return true;
+}
+
+// To avoid issues in sdk_mac build
+#if defined(__ANDROID__)
+
+static bool SetupCgroup(const CgroupDescriptor& descriptor) {
+ const CgroupController* controller = descriptor.controller();
+
+ // mkdir <path> [mode] [owner] [group]
+ if (!Mkdir(controller->path(), descriptor.mode(), descriptor.uid(), descriptor.gid())) {
+ LOG(ERROR) << "Failed to create directory for " << controller->name() << " cgroup";
+ return false;
+ }
+
+ int result;
+ if (controller->version() == 2) {
+ result = mount("none", controller->path(), "cgroup2", MS_NODEV | MS_NOEXEC | MS_NOSUID,
+ nullptr);
+ } else {
+ // Unfortunately historically cpuset controller was mounted using a mount command
+ // different from all other controllers. This results in controller attributes not
+ // to be prepended with controller name. For example this way instead of
+ // /dev/cpuset/cpuset.cpus the attribute becomes /dev/cpuset/cpus which is what
+ // the system currently expects.
+ if (!strcmp(controller->name(), "cpuset")) {
+ // mount cpuset none /dev/cpuset nodev noexec nosuid
+ result = mount("none", controller->path(), controller->name(),
+ MS_NODEV | MS_NOEXEC | MS_NOSUID, nullptr);
+ } else {
+ // mount cgroup none <path> nodev noexec nosuid <controller>
+ result = mount("none", controller->path(), "cgroup", MS_NODEV | MS_NOEXEC | MS_NOSUID,
+ controller->name());
+ }
+ }
+
+ if (result < 0) {
+ PLOG(ERROR) << "Failed to mount " << controller->name() << " cgroup";
+ return false;
+ }
+
+ return true;
+}
+
+#else
+
+// Stubs for non-Android targets.
+static bool SetupCgroup(const CgroupDescriptor&) {
+ return false;
+}
+
+#endif
+
+// WARNING: This function should be called only from SetupCgroups and only once.
+// It intentionally leaks an FD, so additional invocation will result in additional leak.
+static bool WriteRcFile(const std::map<std::string, CgroupDescriptor>& descriptors) {
+ // WARNING: We are intentionally leaking the FD to keep the file open forever.
+ // Let init keep the FD open to prevent file mappings from becoming invalid in
+ // case the file gets deleted somehow.
+ int fd = TEMP_FAILURE_RETRY(open(CGROUPS_RC_PATH, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC,
+ S_IRUSR | S_IRGRP | S_IROTH));
+ if (fd < 0) {
+ PLOG(ERROR) << "open() failed for " << CGROUPS_RC_PATH;
+ return false;
+ }
+
+ CgroupFile fl;
+ fl.version_ = CgroupFile::FILE_CURR_VERSION;
+ fl.controller_count_ = descriptors.size();
+ int ret = TEMP_FAILURE_RETRY(write(fd, &fl, sizeof(fl)));
+ if (ret < 0) {
+ PLOG(ERROR) << "write() failed for " << CGROUPS_RC_PATH;
+ return false;
+ }
+
+ for (const auto& [name, descriptor] : descriptors) {
+ ret = TEMP_FAILURE_RETRY(write(fd, descriptor.controller(), sizeof(CgroupController)));
+ if (ret < 0) {
+ PLOG(ERROR) << "write() failed for " << CGROUPS_RC_PATH;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+CgroupDescriptor::CgroupDescriptor(uint32_t version, const std::string& name,
+ const std::string& path, mode_t mode, const std::string& uid,
+ const std::string& gid)
+ : controller_(version, name, path), mode_(mode), uid_(uid), gid_(gid) {}
+
+bool CgroupSetupCgroups() {
+ std::map<std::string, CgroupDescriptor> descriptors;
+
+ if (getpid() != 1) {
+ LOG(ERROR) << "Cgroup setup can be done only by init process";
+ return false;
+ }
+
+ // Make sure we do this only one time. No need for std::call_once because
+ // init is a single-threaded process
+ if (access(CGROUPS_RC_PATH, F_OK) == 0) {
+ LOG(WARNING) << "Attempt to call SetupCgroups more than once";
+ return true;
+ }
+
+ // load cgroups.json file
+ if (!ReadDescriptors(&descriptors)) {
+ LOG(ERROR) << "Failed to load cgroup description file";
+ return false;
+ }
+
+ // setup cgroups
+ for (const auto& [name, descriptor] : descriptors) {
+ if (!SetupCgroup(descriptor)) {
+ // issue a warning and proceed with the next cgroup
+ // TODO: mark the descriptor as invalid and skip it in WriteRcFile()
+ LOG(WARNING) << "Failed to setup " << name << " cgroup";
+ }
+ }
+
+ // mkdir <CGROUPS_RC_DIR> 0711 system system
+ if (!Mkdir(android::base::Dirname(CGROUPS_RC_PATH), 0711, "system", "system")) {
+ LOG(ERROR) << "Failed to create directory for " << CGROUPS_RC_PATH << " file";
+ return false;
+ }
+
+ // Generate <CGROUPS_RC_FILE> file which can be directly mmapped into
+ // process memory. This optimizes performance, memory usage
+ // and limits infrormation shared with unprivileged processes
+ // to the minimum subset of information from cgroups.json
+ if (!WriteRcFile(descriptors)) {
+ LOG(ERROR) << "Failed to write " << CGROUPS_RC_PATH << " file";
+ return false;
+ }
+
+ // chmod 0644 <CGROUPS_RC_PATH>
+ if (fchmodat(AT_FDCWD, CGROUPS_RC_PATH, 0644, AT_SYMLINK_NOFOLLOW) < 0) {
+ PLOG(ERROR) << "fchmodat() failed";
+ return false;
+ }
+
+ return true;
+}
diff --git a/libprocessgroup/setup/include/processgroup/setup.h b/libprocessgroup/setup/include/processgroup/setup.h
new file mode 100644
index 0000000..b488217
--- /dev/null
+++ b/libprocessgroup/setup/include/processgroup/setup.h
@@ -0,0 +1,19 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+bool CgroupSetupCgroups();