1  /*
       2   * This file is part of strace test suite.
       3   *
       4   * Copyright (c) 2016 Dmitry V. Levin <ldv@strace.io>
       5   * Copyright (c) 2016-2021 The strace developers.
       6   * All rights reserved.
       7   *
       8   * SPDX-License-Identifier: GPL-2.0-or-later
       9   */
      10  
      11  #include "tests.h"
      12  #include <assert.h>
      13  #include <limits.h>
      14  #include <stdio.h>
      15  #include <stdlib.h>
      16  #include <string.h>
      17  #include <unistd.h>
      18  
      19  unsigned long
      20  inode_of_sockfd(const int fd)
      21  {
      22  	assert(fd >= 0);
      23  
      24  	char linkpath[sizeof("/proc/self/fd/%u") + sizeof(int) * 3];
      25  	assert(snprintf(linkpath, sizeof(linkpath), "/proc/self/fd/%u", fd)
      26  	       < (int) sizeof(linkpath));
      27  
      28  	char path[PATH_MAX + 1];
      29  	const ssize_t path_len = readlink(linkpath, path, sizeof(path) - 1);
      30  	if (path_len < 0)
      31  		perror_msg_and_fail("readlink: %s", linkpath);
      32  	path[path_len] = '\0';
      33  
      34  	static const char prefix[] = "socket:[";
      35  	const size_t prefix_len = sizeof(prefix) - 1;
      36  	assert(strncmp(path, prefix, prefix_len) == 0
      37  	       && path[path_len - 1] == ']');
      38  
      39  	return strtoul(path + prefix_len, NULL, 10);
      40  }