--- /dev/null
+/* 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);
+}
+
+/* Exit status after abnormal termination. */
+static int termination_status;
+
+static void
+init_termination_status (void)
+{
+ pid_t pid = xfork ();
+ if (pid == 0)
+ abort ();
+ xwaitpid (pid, &termination_status, 0);
+
+ TEST_VERIFY (WIFSIGNALED (termination_status));
+ TEST_COMPARE (WTERMSIG (termination_status), SIGABRT);
+}
+
+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, termination_status,
+ 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;
+ init_termination_status ();
+
+ 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;
+}
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