glibc/libio/tst-ftell-active-handler.c

/* Verify that ftell returns the correct value at various points before and
   after the handler on which it is called becomes active.
   Copyright (C) 2014 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
   <http://www.gnu.org/licenses/>.  */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <locale.h>
#include <wchar.h>

static int do_test (void);

#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"

#define get_handles_fdopen(filename, fd, fp, fd_mode, mode) \
({									      \
  int ret = 0;								      \
  (fd) = open ((filename), (fd_mode), 0);				      \
  if ((fd) == -1)							      \
    {									      \
      printf ("open failed: %m\n");					      \
      ret = 1;								      \
    }									      \
  else									      \
    {									      \
      (fp) = fdopen ((fd), (mode));					      \
      if ((fp) == NULL)							      \
	{								      \
	  printf ("fdopen failed: %m\n");				      \
	  close (fd);							      \
	  ret = 1;							      \
	}								      \
    }									      \
  ret;									      \
})

#define get_handles_fopen(filename, fd, fp, mode) \
({									      \
  int ret = 0;								      \
  (fp) = fopen ((filename), (mode));					      \
  if ((fp) == NULL)							      \
    {									      \
      printf ("fopen failed: %m\n");					      \
      ret = 1;								      \
    }									      \
  else									      \
    {									      \
      (fd) = fileno (fp);						      \
      if ((fd) == -1)							      \
	{								      \
	  printf ("fileno failed: %m\n");				      \
	  ret = 1;							      \
	}								      \
    }									      \
  ret;									      \
})

/* data points to either char_data or wide_data, depending on whether we're
   testing regular file mode or wide mode respectively.  Similarly,
   fputs_func points to either fputs or fputws.  data_len keeps track of the
   length of the current data and file_len maintains the current file
   length.  */
static const void *data;
static const char *char_data = "abcdef";
static const wchar_t *wide_data = L"abcdef";
static size_t data_len;
static size_t file_len;

typedef int (*fputs_func_t) (const void *data, FILE *fp);
typedef void *(*fgets_func_t) (void *ws, int n, FILE *fp);
fputs_func_t fputs_func;
fgets_func_t fgets_func;

/* This test verifies that the offset reported by ftell is correct after the
   file is truncated using ftruncate.  ftruncate does not change the file
   offset on truncation and hence, SEEK_CUR should continue to point to the
   old offset and not be changed to the new offset.  */
static int
do_ftruncate_test (const char *filename)
{
  FILE *fp = NULL;
  int fd;
  int ret = 0;
  struct test
    {
      const char *mode;
      int fd_mode;
    } test_modes[] = {
	  {"r+", O_RDWR},
	  {"w", O_WRONLY | O_TRUNC},
	  {"w+", O_RDWR | O_TRUNC},
	  {"a", O_WRONLY},
	  {"a+", O_RDWR}
    };

  for (int j = 0; j < 2; j++)
    {
      for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
	{
	  int fileret;
	  printf ("\tftruncate: %s (file, \"%s\"): ",
		  j == 0 ? "fopen" : "fdopen",
		  test_modes[i].mode);

	  if (j == 0)
	    fileret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);
	  else
	    fileret = get_handles_fdopen (filename, fd, fp,
					  test_modes[i].fd_mode,
					  test_modes[i].mode);

	  if (fileret != 0)
	    return fileret;

	  /* Write some data.  */
	  size_t written = fputs_func (data, fp);

	  if (written == EOF)
	    {
	      printf ("fputs[1] failed to write data\n");
	      ret |= 1;
	    }

	  /* Record the offset.  */
	  long offset = ftell (fp);

	  /* Flush data to allow switching active handles.  */
	  if (fflush (fp))
	    {
	      printf ("Flush failed: %m\n");
	      ret |= 1;
	    }

	  /* Now truncate the file.  */
	  if (ftruncate (fd, 0) != 0)
	    {
	      printf ("Failed to truncate file: %m\n");
	      ret |= 1;
	    }

	  /* ftruncate does not change the offset, so there is no need to call
	     anything to be able to switch active handles.  */
	  long new_offset = ftell (fp);

	  /* The offset should remain unchanged since ftruncate does not update
	     it.  */
	  if (offset != new_offset)
	    {
	      printf ("Incorrect offset.  Expected %zu, but got %ld\n",
		      offset, new_offset);

	      ret |= 1;
	    }
	  else
	    printf ("offset = %ld\n", offset);

	  fclose (fp);
	}
    }

  return ret;
}
/* Test that ftell output after a rewind is correct.  */
static int
do_rewind_test (const char *filename)
{
  int ret = 0;
  struct test
    {
      const char *mode;
      int fd_mode;
      size_t old_off;
      size_t new_off;
    } test_modes[] = {
	  {"w", O_WRONLY | O_TRUNC, 0, data_len},
	  {"w+", O_RDWR | O_TRUNC, 0, data_len},
	  {"r+", O_RDWR, 0, data_len},
	  /* The new offsets for 'a' and 'a+' modes have to factor in the
	     previous writes since they always append to the end of the
	     file.  */
	  {"a", O_WRONLY, 0, 3 * data_len},
	  {"a+", O_RDWR, 0, 4 * data_len},
    };

  /* Empty the file before the test so that our offsets are simple to
     calculate.  */
  FILE *fp = fopen (filename, "w");
  if (fp == NULL)
    {
      printf ("Failed to open file for emptying\n");
      return 1;
    }
  fclose (fp);

  for (int j = 0; j < 2; j++)
    {
      for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
	{
	  FILE *fp;
	  int fd;
	  int fileret;

	  printf ("\trewind: %s (file, \"%s\"): ", j == 0 ? "fdopen" : "fopen",
		  test_modes[i].mode);

	  if (j == 0)
	    fileret = get_handles_fdopen (filename, fd, fp,
					  test_modes[i].fd_mode,
					  test_modes[i].mode);
	  else
	    fileret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);

	  if (fileret != 0)
	    return fileret;

	  /* Write some content to the file, rewind and ensure that the ftell
	     output after the rewind is 0.  POSIX does not specify what the
	     behavior is when a file is rewound in 'a' mode, so we retain
	     current behavior, which is to keep the 0 offset.  */
	  size_t written = fputs_func (data, fp);

	  if (written == EOF)
	    {
	      printf ("fputs[1] failed to write data\n");
	      ret |= 1;
	    }

	  rewind (fp);
	  long offset = ftell (fp);

	  if (offset != test_modes[i].old_off)
	    {
	      printf ("Incorrect old offset.  Expected %zu, but got %ld, ",
		      test_modes[i].old_off, offset);
	      ret |= 1;
	    }
	  else
	    printf ("old offset = %ld, ", offset);

	  written = fputs_func (data, fp);

	  if (written == EOF)
	    {
	      printf ("fputs[1] failed to write data\n");
	      ret |= 1;
	    }

	  /* After this write, the offset in append modes should factor in the
	     implicit lseek to the end of file.  */
	  offset = ftell (fp);
	  if (offset != test_modes[i].new_off)
	    {
	      printf ("Incorrect new offset.  Expected %zu, but got %ld\n",
		      test_modes[i].new_off, offset);
	      ret |= 1;
	    }
	  else
	    printf ("new offset = %ld\n", offset);
	}
    }
  return ret;
}

/* Test that the value of ftell is not cached when the stream handle is not
   active.  */
static int
do_ftell_test (const char *filename)
{
  int ret = 0;
  struct test
    {
      const char *mode;
      int fd_mode;
      size_t old_off;
      size_t new_off;
      size_t eof_off;
    } test_modes[] = {
	  /* In w, w+ and r+ modes, the file position should be at the
	     beginning of the file.  After the write, the offset should be
	     updated to data_len.  We don't use eof_off in w and a modes since
	     they don't allow reading.  */
	  {"w", O_WRONLY | O_TRUNC, 0, data_len, 0},
	  {"w+", O_RDWR | O_TRUNC, 0, data_len, 2 * data_len},
	  {"r+", O_RDWR, 0, data_len, 3 * data_len},
	  /* For the 'a' mode, the initial file position should be the
	     current end of file. After the write, the offset has data_len
	     added to the old value.  For a+ mode however, the initial file
	     position is the file position of the underlying file descriptor,
	     since it is initially assumed to be in read mode.  */
	  {"a", O_WRONLY, 3 * data_len, 4 * data_len, 5 * data_len},
	  {"a+", O_RDWR, 0, 5 * data_len, 6 * data_len},
    };
  for (int j = 0; j < 2; j++)
    {
      for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
	{
	  FILE *fp;
	  int fd;
	  int fileret;

	  printf ("\tftell: %s (file, \"%s\"): ", j == 0 ? "fdopen" : "fopen",
		  test_modes[i].mode);

	  if (j == 0)
	    fileret = get_handles_fdopen (filename, fd, fp,
					  test_modes[i].fd_mode,
					  test_modes[i].mode);
	  else
	    fileret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);

	  if (fileret != 0)
	    return fileret;

	  long off = ftell (fp);
	  if (off != test_modes[i].old_off)
	    {
	      printf ("Incorrect old offset.  Expected %zu but got %ld, ",
		      test_modes[i].old_off, off);
	      ret |= 1;
	    }
	  else
	    printf ("old offset = %ld, ", off);

	  /* The effect of this write on the offset should be seen in the ftell
	     call that follows it.  */
	  int write_ret = write (fd, data, data_len);
	  if (write_ret != data_len)
	    {
	      printf ("write failed (%m)\n");
	      ret |= 1;
	    }
	  off = ftell (fp);

	  if (off != test_modes[i].new_off)
	    {
	      printf ("Incorrect new offset.  Expected %zu but got %ld",
		      test_modes[i].new_off, off);
	      ret |= 1;
	    }
	  else
	    printf ("new offset = %ld", off);

	  /* Read to the end, write some data to the fd and check if ftell can
	     see the new ofset.  Do this test only for files that allow
	     reading.  */
	  if (test_modes[i].fd_mode != O_WRONLY)
	    {
	      wchar_t tmpbuf[data_len];

	      rewind (fp);

	      while (fgets_func (tmpbuf, data_len, fp) && !feof (fp));

	      write_ret = write (fd, data, data_len);
	      if (write_ret != data_len)
		{
		  printf ("write failed (%m)\n");
		  ret |= 1;
		}
	      off = ftell (fp);

	      if (off != test_modes[i].eof_off)
		{
		  printf (", Incorrect offset after read EOF.  "
			  "Expected %zu but got %ld\n",
			  test_modes[i].eof_off, off);
		  ret |= 1;
		}
	      else
		printf (", offset after EOF = %ld\n", off);
	    }
	  else
	    putc ('\n', stdout);

	  fclose (fp);
	}
    }

  return ret;
}

/* This test opens the file for writing, moves the file offset of the
   underlying file, writes out data and then checks if ftell trips on it.  */
static int
do_write_test (const char *filename)
{
  FILE *fp = NULL;
  int fd;
  int ret = 0;
  struct test
    {
      const char *mode;
      int fd_mode;
    } test_modes[] = {
	  {"w", O_WRONLY | O_TRUNC},
	  {"w+", O_RDWR | O_TRUNC},
	  {"r+", O_RDWR}
    };

  for (int j = 0; j < 2; j++)
    {
      for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
	{
	  int fileret;
	  printf ("\twrite: %s (file, \"%s\"): ", j == 0 ? "fopen" : "fdopen",
		  test_modes[i].mode);

	  if (j == 0)
	    fileret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);
	  else
	    fileret = get_handles_fdopen (filename, fd, fp,
					  test_modes[i].fd_mode,
					  test_modes[i].mode);

	  if (fileret != 0)
	    return fileret;

	  /* Move offset to just before the end of the file.  */
	  off_t seek_ret = lseek (fd, file_len - 1, SEEK_SET);
	  if (seek_ret == -1)
	    {
	      printf ("lseek failed: %m\n");
	      ret |= 1;
	    }

	  /* Write some data.  */
	  size_t written = fputs_func (data, fp);

	  if (written == EOF)
	    {
	      printf ("fputs[1] failed to write data\n");
	      ret |= 1;
	    }

	  /* Verify that the offset points to the end of the file.  The length
	     of the file would be the original length + the length of data
	     written to it - the amount by which we moved the offset using
	     lseek.  */
	  long offset = ftell (fp);
	  file_len = file_len - 1 + data_len;

	  if (offset != file_len)
	    {
	      printf ("Incorrect offset.  Expected %zu, but got %ld\n",
		      file_len, offset);

	      ret |= 1;
	    }

	  printf ("offset = %ld\n", offset);
	  fclose (fp);
	}
    }

  return ret;
}

/* This test opens a file in append mode, writes some data, and then verifies
   that ftell does not trip over it.  */
static int
do_append_test (const char *filename)
{
  FILE *fp = NULL;
  int ret = 0;
  int fd;

  struct test
    {
      const char *mode;
      int fd_mode;
    } test_modes[] = {
	  {"a", O_WRONLY},
	  {"a+", O_RDWR}
    };

  for (int j = 0; j < 2; j++)
    {
      for (int i = 0; i < sizeof (test_modes) / sizeof (struct test); i++)
	{
	  int fileret;

	  printf ("\tappend: %s (file, \"%s\"): ", j == 0 ? "fopen" : "fdopen",
		  test_modes[i].mode);

	  if (j == 0)
	    fileret = get_handles_fopen (filename, fd, fp, test_modes[i].mode);
	  else
	    fileret = get_handles_fdopen (filename, fd, fp,
					  test_modes[i].fd_mode,
					  test_modes[i].mode);

	  if (fileret != 0)
	    return fileret;

	  /* Write some data.  */
	  size_t written = fputs_func (data, fp);

	  if (written == EOF)
	    {
	      printf ("fputs[1] failed to write all data\n");
	      ret |= 1;
	    }

	  /* Verify that the offset points to the end of the file.  The file
	     len is maintained by adding data_len each time to reflect the data
	     written to it.  */
	  long offset = ftell (fp);
	  file_len += data_len;

	  if (offset != file_len)
	    {
	      printf ("Incorrect offset.  Expected %zu, but got %ld\n",
		      file_len, offset);

	      ret |= 1;
	    }

	  printf ("offset = %ld\n", offset);
	  fclose (fp);
	}
    }

  /* For fdopen in 'a' mode, the file descriptor should not change if the file
     is already open with the O_APPEND flag set.  */
  fd = open (filename, O_WRONLY | O_APPEND, 0);
  if (fd == -1)
    {
      printf ("open(O_APPEND) failed: %m\n");
      return 1;
    }

  off_t seek_ret = lseek (fd, file_len - 1, SEEK_SET);
  if (seek_ret == -1)
    {
      printf ("lseek[O_APPEND][0] failed: %m\n");
      ret |= 1;
    }

  fp = fdopen (fd, "a");
  if (fp == NULL)
    {
      printf ("fdopen(O_APPEND) failed: %m\n");
      close (fd);
      return 1;
    }

  off_t new_seek_ret = lseek (fd, 0, SEEK_CUR);
  if (seek_ret == -1)
    {
      printf ("lseek[O_APPEND][1] failed: %m\n");
      ret |= 1;
    }

  printf ("\tappend: fdopen (file, \"a\"): O_APPEND: ");

  if (seek_ret != new_seek_ret)
    {
      printf ("incorrectly modified file offset to %ld, should be %ld",
	      new_seek_ret, seek_ret);
      ret |= 1;
    }
  else
    printf ("retained current file offset %ld", seek_ret);

  new_seek_ret = ftello (fp);

  if (seek_ret != new_seek_ret)
    {
      printf (", ftello reported incorrect offset %ld, should be %ld\n",
	      new_seek_ret, seek_ret);
      ret |= 1;
    }
  else
    printf (", ftello reported correct offset %ld\n", seek_ret);

  fclose (fp);

  return ret;
}

static int
do_one_test (const char *filename)
{
  int ret = 0;

  ret |= do_ftell_test (filename);
  ret |= do_write_test (filename);
  ret |= do_append_test (filename);
  ret |= do_rewind_test (filename);
  ret |= do_ftruncate_test (filename);

  return ret;
}

/* Run a set of tests for ftell for regular files and wide mode files.  */
static int
do_test (void)
{
  int ret = 0;
  FILE *fp = NULL;
  char *filename;
  size_t written;
  int fd = create_temp_file ("tst-active-handler-tmp.", &filename);

  if (fd == -1)
    {
      printf ("create_temp_file: %m\n");
      return 1;
    }

  fp = fdopen (fd, "w");
  if (fp == NULL)
    {
      printf ("fdopen[0]: %m\n");
      close (fd);
      return 1;
    }

  data = char_data;
  data_len = strlen (char_data);
  file_len = strlen (char_data);
  written = fputs (data, fp);

  if (written == EOF)
    {
      printf ("fputs[1] failed to write data\n");
      ret = 1;
    }

  fclose (fp);
  if (ret)
    return ret;

  /* Tests for regular files.  */
  puts ("Regular mode:");
  fputs_func = (fputs_func_t) fputs;
  fgets_func = (fgets_func_t) fgets;
  data = char_data;
  data_len = strlen (char_data);
  ret |= do_one_test (filename);

  /* Truncate the file before repeating the tests in wide mode.  */
  fp = fopen (filename, "w");
  if (fp == NULL)
    {
      printf ("fopen failed %m\n");
      return 1;
    }
  fclose (fp);

  /* Tests for wide files.  */
  puts ("Wide mode:");
  if (setlocale (LC_ALL, "en_US.UTF-8") == NULL)
    {
      printf ("Cannot set en_US.UTF-8 locale.\n");
      return 1;
    }
  fputs_func = (fputs_func_t) fputws;
  fgets_func = (fgets_func_t) fgetws;
  data = wide_data;
  data_len = wcslen (wide_data);
  ret |= do_one_test (filename);

  return ret;
}