/* Test for libio vtables and their validation.  Common code.

   Copyright (C) 2018 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/>.  */

/* This test provides some coverage for how various stdio functions

   use the vtables in FILE * objects.  The focus is mostly on which

   functions call which methods, not so much on validating data

   processing.  An initial series of tests check that custom vtables

   do not work without activation through _IO_init.

   Note: libio vtables are deprecated feature.  Do not use this test

   as a documentation source for writing custom vtables.  See

   fopencookie for a different way of creating custom stdio

   streams.  */

#include <stdbool.h>

#include <string.h>

#include <support/capture_subprocess.h>

#include <support/check.h>

#include <support/namespace.h>

#include <support/support.h>

#include <support/test-driver.h>

#include <support/xunistd.h>

#include "libioP.h"

/* Data shared between the test subprocess and the test driver in the

   parent.  Note that *shared is reset at the start of the check_call

   function.  */

struct shared

{

  /* Expected file pointer for method calls.  */

  FILE *fp;

  /* If true, assume that a call to _IO_init is needed to enable

     custom vtables.  */

  bool initially_disabled;

  /* Requested return value for the methods which have one.  */

  int return_value;

  /* A value (usually a character) recorded by some of the methods

     below.  */

  int value;

  /* Likewise, for some data.  */

  char buffer[16];

  size_t buffer_length;

  /* Total number of method calls.  */

  unsigned int calls;

  /* Individual method call counts.  */

  unsigned int calls_finish;

  unsigned int calls_overflow;

  unsigned int calls_underflow;

  unsigned int calls_uflow;

  unsigned int calls_pbackfail;

  unsigned int calls_xsputn;

  unsigned int calls_xsgetn;

  unsigned int calls_seekoff;

  unsigned int calls_seekpos;

  unsigned int calls_setbuf;

  unsigned int calls_sync;

  unsigned int calls_doallocate;

  unsigned int calls_read;

  unsigned int calls_write;

  unsigned int calls_seek;

  unsigned int calls_close;

  unsigned int calls_stat;

  unsigned int calls_showmanyc;

  unsigned int calls_imbue;

} *shared;

/* Method implementations which increment the counters in *shared.  */

static void

log_method (FILE *fp, const char *name)

{

  if (test_verbose > 0)

    printf ("info: %s (%p) called\n", name, fp);

}

static void

method_finish (FILE *fp, int dummy)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_finish;

}

static int

method_overflow (FILE *fp, int ch)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_overflow;

  shared->value = ch;

  return shared->return_value;

}

static int

method_underflow (FILE *fp)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_underflow;

  return shared->return_value;

}

static int

method_uflow (FILE *fp)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_uflow;

  return shared->return_value;

}

static int

method_pbackfail (FILE *fp, int ch)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_pbackfail;

  shared->value = ch;

  return shared->return_value;

}

static size_t

method_xsputn (FILE *fp, const void *data, size_t n)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_xsputn;

  size_t to_copy = n;

  if (n > sizeof (shared->buffer))

    to_copy = sizeof (shared->buffer);

  memcpy (shared->buffer, data, to_copy);

  shared->buffer_length = to_copy;

  return to_copy;

}

static size_t

method_xsgetn (FILE *fp, void *data, size_t n)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_xsgetn;

  return 0;

}

static off64_t

method_seekoff (FILE *fp, off64_t offset, int dir, int mode)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_seekoff;

  return shared->return_value;

}

static off64_t

method_seekpos (FILE *fp, off64_t offset, int mode)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_seekpos;

  return shared->return_value;

}

static FILE *

method_setbuf (FILE *fp, char *buffer, ssize_t length)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_setbuf;

  return fp;

}

static int

method_sync (FILE *fp)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_sync;

  return shared->return_value;

}

static int

method_doallocate (FILE *fp)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_doallocate;

  return shared->return_value;

}

static ssize_t

method_read (FILE *fp, void *data, ssize_t length)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_read;

  return shared->return_value;

}

static ssize_t

method_write (FILE *fp, const void *data, ssize_t length)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_write;

  return shared->return_value;

}

static off64_t

method_seek (FILE *fp, off64_t offset, int mode)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_seek;

  return shared->return_value;

}

static int

method_close (FILE *fp)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_close;

  return shared->return_value;

}

static int

method_stat (FILE *fp, void *buffer)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_stat;

  return shared->return_value;

}

static int

method_showmanyc (FILE *fp)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_showmanyc;

  return shared->return_value;

}

static void

method_imbue (FILE *fp, void *locale)

{

  log_method (fp, __func__);

  TEST_VERIFY (fp == shared->fp);

  ++shared->calls;

  ++shared->calls_imbue;

}

/* Our custom vtable.  */

static const struct _IO_jump_t jumps =

{

  JUMP_INIT_DUMMY,

  JUMP_INIT (finish, method_finish),

  JUMP_INIT (overflow, method_overflow),

  JUMP_INIT (underflow, method_underflow),

  JUMP_INIT (uflow, method_uflow),

  JUMP_INIT (pbackfail, method_pbackfail),

  JUMP_INIT (xsputn, method_xsputn),

  JUMP_INIT (xsgetn, method_xsgetn),

  JUMP_INIT (seekoff, method_seekoff),

  JUMP_INIT (seekpos, method_seekpos),

  JUMP_INIT (setbuf, method_setbuf),

  JUMP_INIT (sync, method_sync),

  JUMP_INIT (doallocate, method_doallocate),

  JUMP_INIT (read, method_read),

  JUMP_INIT (write, method_write),

  JUMP_INIT (seek, method_seek),

  JUMP_INIT (close, method_close),

  JUMP_INIT (stat, method_stat),

  JUMP_INIT (showmanyc, method_showmanyc),

  JUMP_INIT (imbue, method_imbue)

};

/* Our file implementation.  */

struct my_file

{

  FILE f;

  const struct _IO_jump_t *vtable;

};

struct my_file

my_file_create (void)

{

  return (struct my_file)

    {

      /* Disable locking, so that we do not have to set up a lock

         pointer.  */

      .f._flags =  _IO_USER_LOCK,

      /* Copy the offset from the an initialized handle, instead of

         figuring it out from scratch.  */

      .f._vtable_offset = stdin->_vtable_offset,

      .vtable = &jumps,

    };

}

/* Initial tests which do not enable vtable compatibility.  */

/* Inhibit GCC optimization of fprintf.  */

typedef int (*fprintf_type) (FILE *, const char *, ...);

static const volatile fprintf_type fprintf_ptr = &fprintf;

static void

without_compatibility_fprintf (void *closure)

{

  /* This call should abort.  */

  fprintf_ptr (shared->fp, " ");

  _exit (1);

}

static void

without_compatibility_fputc (void *closure)

{

  /* This call should abort.  */

  fputc (' ', shared->fp);

  _exit (1);

}

static void

without_compatibility_fgetc (void *closure)

{

  /* This call should abort.  */

  fgetc (shared->fp);

  _exit (1);

}

static void

without_compatibility_fflush (void *closure)

{

  /* This call should abort.  */

  fflush (shared->fp);

  _exit (1);

}

static void

check_for_termination (const char *name, void (*callback) (void *))

{

  struct my_file file = my_file_create ();

  shared->fp = &file.f;

  shared->return_value = -1;

  shared->calls = 0;

  struct support_capture_subprocess proc

    = support_capture_subprocess (callback, NULL);

  support_capture_subprocess_check (&proc, name, -SIGABRT,

                                    sc_allow_stderr);

  const char *message

    = "Fatal error: glibc detected an invalid stdio handle\n";

  TEST_COMPARE_BLOB (proc.err.buffer, proc.err.length,

                     message, strlen (message));

  TEST_COMPARE (shared->calls, 0);

  support_capture_subprocess_free (&proc;;

}

/* The test with vtable validation disabled.  */

/* This function does not have a prototype in libioP.h to prevent

   accidental use from within the library (which would disable vtable

   verification).  */

void _IO_init (FILE *fp, int flags);

static void

with_compatibility_fprintf (void *closure)

{

  TEST_COMPARE (fprintf_ptr (shared->fp, "A%sCD", "B"), 4);

  TEST_COMPARE (shared->calls, 3);

  TEST_COMPARE (shared->calls_xsputn, 3);

  TEST_COMPARE_BLOB (shared->buffer, shared->buffer_length,

                     "CD", 2);

}

static void

with_compatibility_fputc (void *closure)

{

  shared->return_value = '@';

  TEST_COMPARE (fputc ('@', shared->fp), '@');

  TEST_COMPARE (shared->calls, 1);

  TEST_COMPARE (shared->calls_overflow, 1);

  TEST_COMPARE (shared->value, '@');

}

static void

with_compatibility_fgetc (void *closure)

{

  shared->return_value = 'X';

  TEST_COMPARE (fgetc (shared->fp), 'X');

  TEST_COMPARE (shared->calls, 1);

  TEST_COMPARE (shared->calls_uflow, 1);

}

static void

with_compatibility_fflush (void *closure)

{

  TEST_COMPARE (fflush (shared->fp), 0);

  TEST_COMPARE (shared->calls, 1);

  TEST_COMPARE (shared->calls_sync, 1);

}

/* Call CALLBACK in a subprocess, after setting up a custom file

   object and updating shared->fp.  */

static void

check_call (const char *name, void (*callback) (void *),

            bool initially_disabled)

{

  *shared = (struct shared)

    {

     .initially_disabled = initially_disabled,

    };

  /* Set up a custom file object.  */

  struct my_file file = my_file_create ();

  shared->fp = &file.f;

  if (shared->initially_disabled)

    _IO_init (shared->fp, file.f._flags);

  if (test_verbose > 0)

    printf ("info: calling test %s\n", name);

  support_isolate_in_subprocess (callback, NULL);

}

/* Run the tests.  INITIALLY_DISABLED indicates whether custom vtables

   are disabled when the test starts.  */

static int

run_tests (bool initially_disabled)

{

  /* The test relies on fatal error messages being printed to standard

     error.  */

  setenv ("LIBC_FATAL_STDERR_", "1", 1);

  shared = support_shared_allocate (sizeof (*shared));

  shared->initially_disabled = initially_disabled;

  if (initially_disabled)

    {

      check_for_termination ("fprintf", without_compatibility_fprintf);

      check_for_termination ("fputc", without_compatibility_fputc);

      check_for_termination ("fgetc", without_compatibility_fgetc);

      check_for_termination ("fflush", without_compatibility_fflush);

    }

  check_call ("fprintf", with_compatibility_fprintf, initially_disabled);

  check_call ("fputc", with_compatibility_fputc, initially_disabled);

  check_call ("fgetc", with_compatibility_fgetc, initially_disabled);

  check_call ("fflush", with_compatibility_fflush, initially_disabled);

  support_shared_free (shared);

  shared = NULL;

  return 0;

}