glibc/io/tst-fcntl.c

/* Tests for fcntl.
   Copyright (C) 2000-2024 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>


/* Prototype for our test function.  */
extern void do_prepare (int argc, char *argv[]);
extern int do_test (int argc, char *argv[]);

/* We have a preparation function.  */
#define PREPARE do_prepare

#include "../test-skeleton.c"


/* Name of the temporary files.  */
static char *name;

/* File descriptor to temporary file.  */
static int fd;

void
do_prepare (int argc, char *argv[])
{
   size_t name_len;

   name_len = strlen (test_dir);
   name = xmalloc (name_len + sizeof ("/fcntlXXXXXX"));
   mempcpy (mempcpy (name, test_dir, name_len),
	    "/fcntlXXXXXX", sizeof ("/fcntlXXXXXX"));
  /* Create the temporary file.  */
  fd = mkstemp (name);
  if (fd == -1)
    {
      printf ("cannot open temporary file: %m\n");
      exit (1);
    }
   add_temp_file (name);
}


int
do_test (int argc, char *argv[])
{
  int fd2;
  int fd3;
  struct stat64 st;
  int val;
  int result = 0;

  if (fstat64 (fd, &st) != 0)
    {
      printf ("cannot stat test file: %m\n");
      return 1;
    }
  if (! S_ISREG (st.st_mode) || st.st_size != 0)
    {
      puts ("file not created correctly");
      return 1;
    }

  /* Get the flags with fcntl().  */
  val = fcntl (fd, F_GETFL);
  if (val == -1)
    {
      printf ("fcntl(fd, F_GETFL) failed: %m\n");
      result = 1;
    }
  else if ((val & O_ACCMODE) != O_RDWR)
    {
      puts ("temporary file not opened for read and write");
      result = 1;
    }

  /* Set the flags to something else.  */
  if (fcntl (fd, F_SETFL, O_RDONLY) == -1)
    {
      printf ("fcntl(fd, F_SETFL, O_RDONLY) failed: %m\n");
      result = 1;
    }

  val = fcntl (fd, F_GETFL);
  if (val == -1)
    {
      printf ("fcntl(fd, F_GETFL) after F_SETFL failed: %m\n");
      result = 1;
    }
  else if ((val & O_ACCMODE) != O_RDWR)
    {
      puts ("temporary file access mode changed");
      result = 1;
    }

  /* Set the flags to something else.  */
  if (fcntl (fd, F_SETFL, O_APPEND) == -1)
    {
      printf ("fcntl(fd, F_SETFL, O_APPEND) failed: %m\n");
      result = 1;
    }

  val = fcntl (fd, F_GETFL);
  if (val == -1)
    {
      printf ("fcntl(fd, F_GETFL) after second F_SETFL failed: %m\n");
      result = 1;
    }
  else if ((val & O_APPEND) == 0)
    {
      puts ("O_APPEND not set");
      result = 1;
    }

  val = fcntl (fd, F_GETFD);
  if (val == -1)
    {
      printf ("fcntl(fd, F_GETFD) failed: %m\n");
      result = 1;
    }
  else if (fcntl (fd, F_SETFD, val | FD_CLOEXEC) == -1)
    {
      printf ("fcntl(fd, F_SETFD, FD_CLOEXEC) failed: %m\n");
      result = 1;
    }
  else
    {
      val = fcntl (fd, F_GETFD);
      if (val == -1)
	{
	  printf ("fcntl(fd, F_GETFD) after F_SETFD failed: %m\n");
	  result = 1;
	}
      else if ((val & FD_CLOEXEC) == 0)
	{
	  puts ("FD_CLOEXEC not set");
	  result = 1;
	}
    }

  /* Get a number of a free descriptor.  If /dev/null is not available
     don't continue testing.  */
  fd2 = open (_PATH_DEVNULL, O_RDWR);
  if (fd2 == -1)
    return result;
  close (fd2);

  fd3 = fcntl (fd, F_DUPFD, fd2 + 1);
  if (fd3 == -1)
    {
      printf ("fcntl(fd, F_DUPFD, %d) failed: %m\n", fd2 + 1);
      result = 1;
    }
  else if (fd3 <= fd2)
    {
      printf ("F_DUPFD returned %d which is not larger than %d\n", fd3, fd2);
      result = 1;
    }

  if (fd3 != -1)
    {
      val = fcntl (fd3, F_GETFD);
      if (val == -1)
	{
	  printf ("fcntl(fd3, F_GETFD) after F_DUPFD failed: %m\n");
	  result = 1;
	}
      else if ((val & FD_CLOEXEC) != 0)
	{
	  puts ("FD_CLOEXEC still set");
	  result = 1;
	}

      close (fd3);
    }

  return result;
}