Move public libraries list to a separate source file

Functions for reading the public libraries list are moved out of
library_namespace.cpp to public_libraries.cpp.

In addition, library-local symbols are moved from android namespace to
android::nativeloader namespace.

Bug: 130388701
Test: build & pass presubmit tests
Change-Id: If82419598304d56d29bfec4ef553443c788d0f53
diff --git a/libnativeloader/public_libraries.cpp b/libnativeloader/public_libraries.cpp
new file mode 100644
index 0000000..8e3f9e8
--- /dev/null
+++ b/libnativeloader/public_libraries.cpp
@@ -0,0 +1,322 @@
+/*
+ * 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 "public_libraries.h"
+#define LOG_TAG "nativeloader"
+
+#include <dirent.h>
+
+#include <algorithm>
+#include <memory>
+
+#include "android-base/file.h"
+#include "android-base/logging.h"
+#include "android-base/properties.h"
+#include "android-base/strings.h"
+#include "log/log.h"
+
+namespace android::nativeloader {
+
+using namespace std::string_literals;
+
+namespace {
+// TODO(b/130388701) simplify the names below
+constexpr const char kPublicNativeLibrariesSystemConfigPathFromRoot[] = "/etc/public.libraries.txt";
+constexpr const char kPublicNativeLibrariesExtensionConfigPrefix[] = "public.libraries-";
+constexpr const size_t kPublicNativeLibrariesExtensionConfigPrefixLen =
+    sizeof(kPublicNativeLibrariesExtensionConfigPrefix) - 1;
+constexpr const char kPublicNativeLibrariesExtensionConfigSuffix[] = ".txt";
+constexpr const size_t kPublicNativeLibrariesExtensionConfigSuffixLen =
+    sizeof(kPublicNativeLibrariesExtensionConfigSuffix) - 1;
+constexpr const char kPublicNativeLibrariesVendorConfig[] = "/vendor/etc/public.libraries.txt";
+constexpr const char kLlndkNativeLibrariesSystemConfigPathFromRoot[] = "/etc/llndk.libraries.txt";
+constexpr const char kVndkspNativeLibrariesSystemConfigPathFromRoot[] = "/etc/vndksp.libraries.txt";
+
+const std::vector<const std::string> kRuntimePublicLibraries = {
+    "libicuuc.so",
+    "libicui18n.so",
+};
+
+// TODO(b/130388701) use macro LIB to eliminate the conditional
+#if defined(__LP64__)
+constexpr const char* kRuntimeApexLibPath = "/apex/com.android.runtime/lib64";
+#else
+constexpr const char* kRuntimeApexLibPath = "/apex/com.android.runtime/lib";
+#endif
+
+std::string root_dir() {
+  static const char* android_root_env = getenv("ANDROID_ROOT");
+  return android_root_env != nullptr ? android_root_env : "/system";
+}
+
+bool debuggable() {
+  bool debuggable = false;
+  debuggable = android::base::GetBoolProperty("ro.debuggable", false);
+  return debuggable;
+}
+
+std::string vndk_version_str() {
+  std::string version = android::base::GetProperty("ro.vndk.version", "");
+  if (version != "" && version != "current") {
+    return "." + version;
+  }
+  return "";
+}
+
+void insert_vndk_version_str(std::string* file_name) {
+  CHECK(file_name != nullptr);
+  size_t insert_pos = file_name->find_last_of(".");
+  if (insert_pos == std::string::npos) {
+    insert_pos = file_name->length();
+  }
+  file_name->insert(insert_pos, vndk_version_str());
+}
+
+const std::function<bool(const std::string&, std::string*)> always_true =
+    [](const std::string&, std::string*) { return true; };
+
+bool ReadConfig(const std::string& configFile, std::vector<std::string>* sonames,
+                const std::function<bool(const std::string& /* soname */,
+                                         std::string* /* error_msg */)>& check_soname,
+                std::string* error_msg = nullptr) {
+  // Read list of public native libraries from the config file.
+  std::string file_content;
+  if (!base::ReadFileToString(configFile, &file_content)) {
+    if (error_msg) *error_msg = strerror(errno);
+    return false;
+  }
+
+  std::vector<std::string> lines = base::Split(file_content, "\n");
+
+  for (auto& line : lines) {
+    auto trimmed_line = base::Trim(line);
+    if (trimmed_line[0] == '#' || trimmed_line.empty()) {
+      continue;
+    }
+    size_t space_pos = trimmed_line.rfind(' ');
+    if (space_pos != std::string::npos) {
+      std::string type = trimmed_line.substr(space_pos + 1);
+      if (type != "32" && type != "64") {
+        if (error_msg) *error_msg = "Malformed line: " + line;
+        return false;
+      }
+#if defined(__LP64__)
+      // Skip 32 bit public library.
+      if (type == "32") {
+        continue;
+      }
+#else
+      // Skip 64 bit public library.
+      if (type == "64") {
+        continue;
+      }
+#endif
+      trimmed_line.resize(space_pos);
+    }
+
+    if (check_soname(trimmed_line, error_msg)) {
+      sonames->push_back(trimmed_line);
+    } else {
+      return false;
+    }
+  }
+  return true;
+}
+
+void ReadExtensionLibraries(const char* dirname, std::vector<std::string>* sonames) {
+  std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(dirname), closedir);
+  if (dir != nullptr) {
+    // Failing to opening the dir is not an error, which can happen in
+    // webview_zygote.
+    while (struct dirent* ent = readdir(dir.get())) {
+      if (ent->d_type != DT_REG && ent->d_type != DT_LNK) {
+        continue;
+      }
+      const std::string filename(ent->d_name);
+      if (android::base::StartsWith(filename, kPublicNativeLibrariesExtensionConfigPrefix) &&
+          android::base::EndsWith(filename, kPublicNativeLibrariesExtensionConfigSuffix)) {
+        const size_t start = kPublicNativeLibrariesExtensionConfigPrefixLen;
+        const size_t end = filename.size() - kPublicNativeLibrariesExtensionConfigSuffixLen;
+        const std::string company_name = filename.substr(start, end - start);
+        const std::string config_file_path = dirname + "/"s + filename;
+        LOG_ALWAYS_FATAL_IF(
+            company_name.empty(),
+            "Error extracting company name from public native library list file path \"%s\"",
+            config_file_path.c_str());
+
+        std::string error_msg;
+
+        LOG_ALWAYS_FATAL_IF(
+            !ReadConfig(config_file_path, sonames,
+                        [&company_name](const std::string& soname, std::string* error_msg) {
+                          if (android::base::StartsWith(soname, "lib") &&
+                              android::base::EndsWith(soname, "." + company_name + ".so")) {
+                            return true;
+                          } else {
+                            *error_msg = "Library name \"" + soname +
+                                         "\" does not end with the company name: " + company_name +
+                                         ".";
+                            return false;
+                          }
+                        },
+                        &error_msg),
+            "Error reading public native library list from \"%s\": %s", config_file_path.c_str(),
+            error_msg.c_str());
+      }
+    }
+  }
+}
+
+}  // namespace
+
+const std::string& system_public_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    std::string config_file = root_dir() + kPublicNativeLibrariesSystemConfigPathFromRoot;
+    std::vector<std::string> sonames;
+    std::string error_msg;
+    LOG_ALWAYS_FATAL_IF(!ReadConfig(config_file, &sonames, always_true, &error_msg),
+                        "Error reading public native library list from \"%s\": %s",
+                        config_file.c_str(), error_msg.c_str());
+
+    // For debuggable platform builds use ANDROID_ADDITIONAL_PUBLIC_LIBRARIES environment
+    // variable to add libraries to the list. This is intended for platform tests only.
+    if (debuggable()) {
+      const char* additional_libs = getenv("ANDROID_ADDITIONAL_PUBLIC_LIBRARIES");
+      if (additional_libs != nullptr && additional_libs[0] != '\0') {
+        std::vector<std::string> additional_libs_vector = base::Split(additional_libs, ":");
+        std::copy(additional_libs_vector.begin(), additional_libs_vector.end(),
+                  std::back_inserter(sonames));
+      }
+    }
+
+    // Remove the public libs in the runtime namespace.
+    // These libs are listed in public.android.txt, but we don't want the rest of android
+    // in default namespace to dlopen the libs.
+    // For example, libicuuc.so is exposed to classloader namespace from runtime namespace.
+    // Unfortunately, it does not have stable C symbols, and default namespace should only use
+    // stable symbols in libandroidicu.so. http://b/120786417
+    for (const std::string& lib_name : kRuntimePublicLibraries) {
+      std::string path(kRuntimeApexLibPath);
+      path.append("/").append(lib_name);
+
+      struct stat s;
+      // Do nothing if the path in /apex does not exist.
+      // Runtime APEX must be mounted since libnativeloader is in the same APEX
+      if (stat(path.c_str(), &s) != 0) {
+        continue;
+      }
+
+      auto it = std::find(sonames.begin(), sonames.end(), lib_name);
+      if (it != sonames.end()) {
+        sonames.erase(it);
+      }
+    }
+    list = android::base::Join(sonames, ':');
+    cached = true;
+  }
+  return list;
+}
+
+const std::string& runtime_public_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    list = android::base::Join(kRuntimePublicLibraries, ":");
+    // For debuggable platform builds use ANDROID_ADDITIONAL_PUBLIC_LIBRARIES environment
+    // variable to add libraries to the list. This is intended for platform tests only.
+    if (debuggable()) {
+      const char* additional_libs = getenv("ANDROID_ADDITIONAL_PUBLIC_LIBRARIES");
+      if (additional_libs != nullptr && additional_libs[0] != '\0') {
+        list = list + ':' + additional_libs;
+      }
+    }
+  }
+  return list;
+}
+
+const std::string& vendor_public_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    // This file is optional, quietly ignore if the file does not exist.
+    std::vector<std::string> sonames;
+    ReadConfig(kPublicNativeLibrariesVendorConfig, &sonames, always_true, nullptr);
+    list = android::base::Join(sonames, ':');
+    cached = true;
+  }
+  return list;
+}
+
+// read /system/etc/public.libraries-<companyname>.txt which contain partner defined
+// system libs that are exposed to apps. The libs in the txt files must be
+// named as lib<name>.<companyname>.so.
+const std::string& oem_public_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    std::vector<std::string> sonames;
+    ReadExtensionLibraries("/system/etc", &sonames);
+    list = android::base::Join(sonames, ':');
+    cached = true;
+  }
+  return list;
+}
+
+// read /product/etc/public.libraries-<companyname>.txt which contain partner defined
+// product libs that are exposed to apps.
+const std::string& product_public_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    std::vector<std::string> sonames;
+    ReadExtensionLibraries("/product/etc", &sonames);
+    list = android::base::Join(sonames, ':');
+    cached = true;
+  }
+  return list;
+}
+
+const std::string& system_llndk_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    std::string config_file = root_dir() + kLlndkNativeLibrariesSystemConfigPathFromRoot;
+    insert_vndk_version_str(&config_file);
+    std::vector<std::string> sonames;
+    ReadConfig(config_file, &sonames, always_true, nullptr);
+    list = android::base::Join(sonames, ':');
+    cached = true;
+  }
+  return list;
+}
+
+const std::string& system_vndksp_libraries() {
+  static bool cached = false;
+  static std::string list;
+  if (!cached) {
+    std::string config_file = root_dir() + kVndkspNativeLibrariesSystemConfigPathFromRoot;
+    insert_vndk_version_str(&config_file);
+    std::vector<std::string> sonames;
+    ReadConfig(config_file, &sonames, always_true, nullptr);
+    list = android::base::Join(sonames, ':');
+    cached = true;
+  }
+  return list;
+}
+
+}  // namespace android::nativeloader