sandboxed-api/sandboxed_api/sandbox2/testcases/print_fds.cc

// Copyright 2019 Google LLC
//
// 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
//
//     https://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.

// A binary that prints its opened file descriptors.

#include <fcntl.h>

#include <cstdio>

int main(int argc, char** argv) {
  for (int fd = 0; fd < 4096; fd++) {
    if (fcntl(fd, F_GETFD) != -1) {
      printf("%d\n", fd);
    }
  }
}