text: /*
   *
   * Copyright 2018 gRPC authors.
   *
   * 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 <grpc/support/port_platform.h>
  
  #include <grpc/slice_buffer.h>
  #include "src/core/lib/security/security_connector/load_system_roots_linux.h"
  
  #ifdef GPR_LINUX
  
  #include "src/core/lib/security/security_connector/load_system_roots.h"
  
  #include <dirent.h>
  #include <fcntl.h>
  #include <stdbool.h>
  #include <string.h>
  #include <sys/param.h>
  #include <sys/stat.h>
  #include <sys/types.h>
  #include <unistd.h>
  
  #include <grpc/support/alloc.h>
  #include <grpc/support/log.h>
  #include <grpc/support/string_util.h>
  
  #include "src/core/lib/gpr/string.h"
  #include "src/core/lib/gpr/useful.h"
  #include "src/core/lib/gprpp/global_config.h"
  #include "src/core/lib/gprpp/inlined_vector.h"
  #include "src/core/lib/iomgr/load_file.h"
  
  GPR_GLOBAL_CONFIG_DEFINE_STRING(grpc_system_ssl_roots_dir, "",
                                  "Custom directory to SSL Roots");
  
  namespace grpc_core {
  namespace {
  
  const char* kLinuxCertFiles[] = {
      "/etc/ssl/certs/ca-certificates.crt", "/etc/pki/tls/certs/ca-bundle.crt",
      "/etc/ssl/ca-bundle.pem", "/etc/pki/tls/cacert.pem",
      "/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem"};
  const char* kLinuxCertDirectories[] = {
      "/etc/ssl/certs", "/system/etc/security/cacerts", "/usr/local/share/certs",
      "/etc/pki/tls/certs", "/etc/openssl/certs"};
  
  grpc_slice GetSystemRootCerts() {
    grpc_slice valid_bundle_slice = grpc_empty_slice();
    size_t num_cert_files_ = GPR_ARRAY_SIZE(kLinuxCertFiles);
    for (size_t i = 0; i < num_cert_files_; i++) {
      grpc_error* error =
          grpc_load_file(kLinuxCertFiles[i], 1, &valid_bundle_slice);
      if (error == GRPC_ERROR_NONE) {
        return valid_bundle_slice;
      }
    }
    return grpc_empty_slice();
  }
  
  }  // namespace
  
  void GetAbsoluteFilePath(const char* valid_file_dir,
                           const char* file_entry_name, char* path_buffer) {
    if (valid_file_dir != nullptr && file_entry_name != nullptr) {
      int path_len = snprintf(path_buffer, MAXPATHLEN, "%s/%s", valid_file_dir,
                              file_entry_name);
      if (path_len == 0) {
        gpr_log(GPR_ERROR, "failed to get absolute path for file: %s",
                file_entry_name);
      }
    }
  }
  
  grpc_slice CreateRootCertsBundle(const char* certs_directory) {
    grpc_slice bundle_slice = grpc_empty_slice();
    if (certs_directory == nullptr) {
      return bundle_slice;
    }
    DIR* ca_directory = opendir(certs_directory);
    if (ca_directory == nullptr) {
      return bundle_slice;
    }
    struct FileData {
      char path[MAXPATHLEN];
      off_t size;
    };
    InlinedVector<FileData, 2> roots_filenames;
    size_t total_bundle_size = 0;
    struct dirent* directory_entry;
    while ((directory_entry = readdir(ca_directory)) != nullptr) {
      struct stat dir_entry_stat;
      const char* file_entry_name = directory_entry->d_name;
      FileData file_data;
      GetAbsoluteFilePath(certs_directory, file_entry_name, file_data.path);
      int stat_return = stat(file_data.path, &dir_entry_stat);
      if (stat_return == -1 || !S_ISREG(dir_entry_stat.st_mode)) {
        // no subdirectories.
        if (stat_return == -1) {
          gpr_log(GPR_ERROR, "failed to get status for file: %s", file_data.path);
        }
        continue;
      }
      file_data.size = dir_entry_stat.st_size;
      total_bundle_size += file_data.size;
      roots_filenames.push_back(file_data);
    }
    closedir(ca_directory);
    char* bundle_string = static_cast<char*>(gpr_zalloc(total_bundle_size + 1));
    size_t bytes_read = 0;
    for (size_t i = 0; i < roots_filenames.size(); i++) {
      int file_descriptor = open(roots_filenames[i].path, O_RDONLY);
      if (file_descriptor != -1) {
        // Read file into bundle.
        size_t cert_file_size = roots_filenames[i].size;
        int read_ret =
            read(file_descriptor, bundle_string + bytes_read, cert_file_size);
        if (read_ret != -1) {
          bytes_read += read_ret;
        } else {
          gpr_log(GPR_ERROR, "failed to read file: %s", roots_filenames[i].path);
        }
      }
    }
    bundle_slice = grpc_slice_new(bundle_string, bytes_read, gpr_free);
    return bundle_slice;
  }
  
  grpc_slice LoadSystemRootCerts() {
    grpc_slice result = grpc_empty_slice();
    // Prioritize user-specified custom directory if flag is set.
    UniquePtr<char> custom_dir = GPR_GLOBAL_CONFIG_GET(grpc_system_ssl_roots_dir);
    if (strlen(custom_dir.get()) > 0) {
      result = CreateRootCertsBundle(custom_dir.get());
    }
    // If the custom directory is empty/invalid/not specified, fallback to
    // distribution-specific directory.
    if (GRPC_SLICE_IS_EMPTY(result)) {
      result = GetSystemRootCerts();
    }
    if (GRPC_SLICE_IS_EMPTY(result)) {
      for (size_t i = 0; i < GPR_ARRAY_SIZE(kLinuxCertDirectories); i++) {
        result = CreateRootCertsBundle(kLinuxCertDirectories[i]);
        if (!GRPC_SLICE_IS_EMPTY(result)) {
          break;
        }
      }
    }
    return result;
  }
  
  }  // namespace grpc_core
  
  #endif /* GPR_LINUX */
  